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HOME HELP ORNL-TM- 728

Contract No. W-7405-eng-26

Reactor Division

MSRE DESIGN AND OpERclTIONS REPORT

PART I .,-

DESCRIPTION OF REACTOR DESIGN R. C. Robertson

A---- ,

JANUARY 1965 5-

OAK RIDGE NATIONAL LABORATORY O a k Ridge, Tennessee

operated by UNION CARBIDE CORPORATION for the U.S. ATOMIC ENERGY COMMISSION

iii

Reactor Vessel i n Transport J i g P r i o r t o I n s t a l l a t i o n .

PREFACE The r e p o r t on t h e Molten-Salt Reactor Experiment (MSRE) has been arranged i n t o twelve major p a r t s a s shown i n t h e General Index.

Each

of these covers a p a r t i c u l a r phase of t h e p r o j e c t , such as t h e design, s a f e t y analysis, operating procedures, e t c .

An attempt has thus been

made t o avoid much of t h e duplication of material that would r e s u l t i f separate and independent r e p o r t s were prepared on each of these major aspects. 3

Detailed references t o supporting documents, working drawings, and other information sources have been made throughout t h e r e p o r t t o make it o f maximum value t o ORNL personnel.

Each of t h e major d i v i -

sions of t h e r e p o r t contains t h e bibliographical and other appendix information necessary f o r t h a t p a r t . The f i n a l volumes of t h e report, P a r t XII, contain t h e r a t h e r ext e n s i v e l i s t i n g s o f working drawings, specifications, schedules, tabbulations, e t c .

These have been given a more limited d i s t r i b u t i o n .

Most o f t h e reference material i s a v a i l a b l e through t h e Division

of Technical Information Extension, Atonic Energy Commission, P. 0. Box 62, Oak Ridge, Tennessee.

For material not a v a i l a b l e through t h i s

source, such an inter-laboratory correspondence, etc., s p e c i a l arrangements can be made for those having a p a r t i c u l a r i n t e r e s t . None of t h e information contained i n t h i s report i s of a c l a s s i f i e d nature.

vii ACKNOWLEDGMENT The list of biographical references provides an indication of ORNL personnel contributing most valuably to the MSRE literature, and thus to this report. Either directly, or indirectly, all of the forty to fifty engineers and scientists in the Reactor Division assigned to the MSRFi project helped to prepare this material. Personnel in the Chemistry, Metallurgy, Physics, Engineering and Maintenance, and Instrumentation and Controls Divisions of the Laboratory also made extensive contributions. In this broad-based team effort it is impossible to single out individuals more deserving to be mentioned here than others.

-=+

c L

. \I

ix GENERAL INDEX This r e p o r t i s one of a s e r i e s t h a t describes t h e design and operat i o n of t h e Molten-Salt Reactor Experiment. A l l t h e r e p o r t s a r e l i s t e d below.

ORNL-TM-~~~"

MSRE Design and Operations Report, P a r t I, Description of Reactor Design by R . C Robertson

OWL-'151-729

MSRE Design and Operations Report, P a r t 11, Nuclear and Process Instrumentation, by J . R . Tallackson

ORNL-TM-730*

MSRE Design and Operations Report, P a r t 111, Nuclear Analysis, by P. N . Haubenreich and J. R . Engel, B. E. Prince, and H. C . Claiborne

ORNL-TM-731

MSRE Design and Operations Report, P a r t N, Chemistry and Materials, by F. F. Blankenship and A . Taboada

ORNL-TM-73P

MSRE Design and Operations Report, P a r t V, Reactor Safety Analysis Report, by S. E. Beall, P . N . Haubenreich, R . B. Lindauer, and J . R . Tallackson

ORNL-TM-733

MSRE Design and Operations Report, P a r t V I , Operating L i m i t s , by S. E . Beall and R. H. Guymon

MSRE Design and Operations Report, P a r t V I I , Fuel Handling and Processing P l a n t , by R. B. Lindauer

MSRE Design and Operations Report, P a r t V I I I , Operating Procedures, by R. H. Guymon MSRE Design and Operations Report, P a r t M, Safety Procedures and Ehergency Plans, by R . H. Guymon

om-TM-910"

MSRE Design and Operations Report, P a r t X, Maintenanee Fquipment and Procedures, by E. C . Hise and R. Blumberg

*Is sued. **These r e p o r t s w i l l be t h e l a s t i n t h e s e r i e s t o be published

omL-TM-gll**

MSRE Design and Operations Report, P a r t X I , Test Program, by R . H. Guymon and P . N. Haubenreich

MSRE Design and Operations Report, P a r t X I I , L i s t s : Drawings, Specifications, Line Schedules, Instrument Tabulations ( V o l 1 and 2 )

xi f Ld

CONTENTS

...................................................... A C I C N O W I E E ~ ................................................ GEWRAL INDEX ................................................. LIST OF FIGURES ............................................... PREFACE

................................................ 1. INTRODUCTION .............................................. 2 . G E " J IIESCRIPTION ....................................... 2.1 Type ................................................. 2.2 Location ............................................ 2.3 Fuel and Coolant Salts .............................. 2.4 E q u i p e n t and Processes ............................. 2.4.1 Reactor ...................................... 2.4.2 Fuel Pump ................................... 2.4.3 Heat Exchanger .............................. 2.4.4 Coolant Pump ................................ 2.4.5 Radiator .................................... 2.4.6 Drain Tank Systems .......................... 2.4.7 Piping and Flanges .......................... 2.4.8 Heaters ..................................... 2.4.9 Materials ................................... 2.4.10 Cover- and Off-Gas System ................... 2.4.11 I n s t m n t a t i o n and Control Systems ......... 2.5 Fuel Processing ..................................... 2.6 Plant Arrangement ................................... 3 . SITE ...................................................... LIST OF TABLES

-a

4 !'f

. PLANT ..................................................... 4.1 General ............................................. 4.2 Offices ............................................. 4.3 Building ............................................ 4.3.1 4.3.2 4.3.3 4.3.4 4.3.5 4.3.6 4.3.7

3 I

................................

Reactor Cell Drain Tank C e l l Coolant Cell and Coolant Drain Tank C e l l Special Equipment Room Pump Room Service Tunnel Transmitter Room and E l e c t r i c Service Areas 4.3.8 Auxiliary Cells 4.3.9 High-Bay Containment Enclosure 4.3.10 Maintenance Control Room

............................. .... ...................... ...................;............... .............................. . ............................. .............. ....................

vii

ix xxiii

xxix 3

7 7 7 7 9 9 12

14 14 14 17 17 19 19 19 21

23 24 27 35 35 38 38

43 47 51 53 54 54

55 55 56 58

xii Page

........................................ .......................................... .............................. ........................................

4.4 .Of f-Gas Area 4.5 Stack Area 4.6 Vapor-Condensing Tanks 4.7 .Blower House 4.8 Store Room and Cooling Tower 4.9 Diesel House 4.10 Switch House and Motor Generator House 4.11 I n l e t A i r F i l t e r House

........................ ........................................ .............. .............................. 5 . FUEL CIRCULATING SYSTEM ................................... 5.1 ;L&yOUt.............................................. 5.2 Flowsheet ........................................... 5.3 Reactor Vessel and Core ............................. 5.3.1 Description ................................. 5.3.2 Graphite .................................... 5.3.3 Fluid Dynamics. Temperature D i s t r i b u t i o n and Solids Deposition ...................... 5.3.3.1 General ........................... 5.3.3.2 Model Studies ..................... 5.3.3.3 Overall Pressure Drop Across Reactor .......................... 5.3.3.4 Flow D i s t r i b u t o r .................. 5.3.3.5 Cooling Annulus ................... 5.3.3.6 5.3.3.7 5.3.3.8

5;3:4 5.3.5

Reactor Access Nozzle. Plug. and S t r a i n e r Control Rods 5.3.5.1 5.3.5.2 5.3.5.3

5.3.6 5.3.7 5.3.8 5.3.9 5.3.10

Control Rod Worth

.........

Mechanical Design of Reactor Vessel Tubes f o r Neutron Source and Special Detectors support Thermal Shield

.................................... ..................................... .............................. ........................

........................... ................. ..........

..................................... Fuel Circulating Pump ............................... 5.3.11

...

................................ Introduction ...................... Description .......................

Structural Cooling Mechanical Design Shielding Considerations

Heaters

63 63

66 75 75 86 90 90 91 91 93 93 96 98

103

................. Graphite Sampler ............................

5.3.10.1 5.3.10.2 5.3.10.3 5.3.10.4 5.4

........................ .............................. ........................

Lower Head core Upper Head

58 60 60 60 61 61 62 62

104

106 106 107 112

113

118 121 122 125 127 129 130

130 131 133

bctl

xiii Page

-5.4.1

Description

........... ......................... ....................... ............ .................... Hydraulics .................................. Mechanical Design Considerations ............ 5.4.3.1 Volute and Impellers ... ....... . . .. 5.4.3.2 Shaf’t ............................. 5.4.3.3 Bearings .......................... 5.4.3.4 Pump Bowl and Nozzles . ........ .... Thermal-Stress Design Considerations ........ m p supports .,...... .. ........ ..... ....... Heaters ..................................... Fuel-Pump Overflow Tank ........... .. ..... ... 5.4.7.1 Overflow Pipe ..................... 5.4.7.2 Overflow Tank ..................... 5.4.7.3 Tank Support ...................... 5.4.1.1 5.4.1.2 5.4.1.3 5.4.1.4 5.4.1.5

5.4.2 5.4.3

5.4.4 5.4.5 5.4.6 5.4.7

Fuel Heat Exchanger

Description Design Considerations

5.5.3

5.5.4 5.6 f,

.................................

................................. ....................... 5.5.2.1 Heat Transfer ..................... 5.5.2.2 Pressure Drops .................... 5.5.2.3 S t r e s s e s .......................... 5.5.2.4 Vibration ......................... Supports .................................... Heaters .....................................

5.5.1 5.5.2

Rotary-Element Assembly Pump Bowl Drive Motor Lubricating-Oil System O i l Catch Tank

5!5

.......... . .....................

Primary C i r c u l a t i n g System Piping, Supports, Heaters, I n s u l a t i o n , Freeze Flanges ana Freeze Valves

5.6.1 5.6.2 5.6.3 . 5.6.4 ’

............................................. Piping ...................................... Piping S t r e s s e s and F l e x i b i l i t y A n d y s i s .... Supports ..................................... Freeze Flanges ............................... 5.6.4.1 Flanges ........................... 5.6.4.2 R i n g Gasket ....................... 5.6.4.3 S a l t Screen ....................... Clamps ............................ Clanping Frame ... ................. 5.6.4.6 5.6.4.7

Gas leak Rates During Thermal Cycling Loading and S t r e s s e s

..........................

..............

136 137 139 143 14.4 147 149 151 151 151

152 152 154 155 155 158 158 158 160

162 162 168 168 164

170 171 171 172

173 173 174 175 178 180 181 182 183 184 187 188

xiv

. Page

. 5.6.5

190

5.6.5.1 5.6.5.2

190

Definitions of "Deep Frozen, Frozen, Thawed" Thermocouples Freeze Valve 103 Freeze Valves 104, 105 and 106 Freeze Valves 107, 108, 109, 110, 111 and 112 Freeze Valves 205 and 206

.................. ..................... .................. .... ................. 5.6.5.7 ......... Pipe I n s u l a t i o n and Heaters ................. 5.6.5.3 5.6.5.4 5.6.5.5 5.6.5.6

5.6.6

............................... General Description ...............

Freeze Valves

5.6.6.1

General Description and Design Considerations Pipe Heaters Thermal I n s u l a t i o n Pipe Line Thermocouples

...................

...................... . ................ ........... 6 . FUEZ DRAIN TANK SYSTFM .................................... 6.1 General Description and Layout ...................... 6.2 Flowsheet ........................................... 6.3 Drain Tanks Nos . 1 and 2 ............................ 6.3.1 Descrtption .................................. 6.3.2 Design ...................................... 6.3.3 Decay Heat Removal System ................... 6.3.4 Drain Tank E l e c t r i c Heaters and I n s u l a t i o n .. 6.3.5 Supports f o r Drain Tanks .................... 6.4 Fuel Flush Tank ..................................... 6.5 Salt-Transfer Pipe Line Supports .................... 7. SAMPLE3-ENRICHER SYSTEN ................................... 7.1 Brief Description of Operation ...................... 7.2 Design Criteria ..................................... 7.2.1 Sampling .................................... 7.2.2 Enriching ................................... 7.2.3 Poisoning ................................... 7.2.4 Addition of Contaminants .................... 7.2.5 "Containment ................................. 7.2.6 S t r e s s e s .................................... 7.3 Description of Equipment ............................ 7.3.1 Capsules .................................... 7.3.1.1 Sampling Capsules ................. 7.3.1.2 Enriching Capsule ................. 5.6.6.2 5.6.6.3 5.6.6.4

193 193 194 196 198 201

. i.

205 205 208 215 218 220 220 222 226 226 234 234 237 238 240 242

244 244 245 245

246 246 246 246 247 247 247

247 249

. xv Page

. 7.3.2

7.3.3 7.3.4

................... 7.3.2.1 Latchkey ........................... 7.3.2.2. Latch .............................. -Cable ........................................ Pump Bowl Equipment .......................... 7.3.4.1 Capsule Guide Cage ................. 7.3.4.2 Lower Latch Stop ................... Capsule Latch and Latchkey

............................. Transfer Tube ................................ 7.3.5.1 Expansion J o i n t .................... 7.3.5.2 Sleeve ............................. 7.3.5.3 Upper Terminus ..................... Operational and Maintenance Valve Box ........ 7.3.6.1 Valve Box .......................... 7.3.6.2 Valves ............................. Transfer Box ................................. 7.3.7.1 Capsule Access Chamber ............. 7.3.7.2 Capsule Drive Unit &d Box ......... '7.3.7.3 Transfer Box Layout and Cont r u c t i o n .......................... 7.3.7.4 Manipulator ........................ 7.3.7.5 Viewing P o r t s and Periscope ........ 7.3.7.6 Capsule Removal Valve .............. 7.3.7.7 Capsule Removal Tube Assembly ...... Capsule Transporting Equipment ............... 7.3.8.1 Sample Transport Container ......... 7.3.4.3

7.3.5 i

7.3.6

7.3.7

7.3.8

Baffle

249 250 250 250 250 250 252 252 252 252 254 254 254 255 256

256

258 259

260 260 261 262 262

263 263 263 264

... ..................... 7.4 Containment .......................................... 264 '7.5 Shielding ............................................ 267 267 7.6 S t r e s s e s ............................................. 269 7.7 Cover-Gas and Leak-Detection System .................. 7.8 Off-Gas System ....................................... 271 271 7,8.1 System No . 1 ................................. 7.8.2 System No . 2 ................................. 273 7.8.3 Exhaust Hood .................................. 273 7.9 Electrical ........................................... 274 7.10 Coolant-Salt Sampler-Enricher System ................. 274 7.3.8.2 7.3.8.3

Transport Container Removal Tool Transport Cask

. COOLANT-SALT CIRCULATING SYSTESI ............................ 8.1 8.2

....................... ............................................

Layout and General Description Flowsheet

2'77 277 279

mi Page

. 8.3

Coolant-Salt Circulating Pump

285

8.3.1

....................... Description .................................

Hydraulics Stresses Pump Supports Heaters Thermal I n s u l a t i o n

285 289 289

289

8.3.2 8.3.3

8.3.4 8.3.5 8.3.6

8.4

.................................. .................................... ............................... .....................................

.......................... Radiator ............................................ 8.4.1 Description ................................. 8.4.1.1 Coil .............................. 8.4.1.2 Ehclosure and I n s u l a t i o n .......... 8.4.1.3 Doors and Door Mechanism .......... 8.4.1.4 Cooling A i r Blowers, Ducting and Dampers .......................... 8.4.2 S t r e s s ...................................... 8.4.3 8.4.4

................................. Heaters .....................................

Performance

........ ......................... ............................... ................................... ...................... Secondary Circulating System Piping and Supports .... 8.6 Piping Stresses and F l e x i b i l i t y Analysis .... 8.6.1 8.6.2 Coolant-Salt Piping Supports ................ 9 . COOLANT-SALT STORAGE SYSTEM ............................... 9.1 Layout and General Description ...................... 9.2 Flowsheet ........................................... 9.3 Coolant-Salt Drain Tank ............................. 9.3.1 Tank ........................................ 9.3.2 Supports and Weigh Cells .................... 9.3.3 E l e c t r i c Heaters and I n s u l a t i o n ............. 9.3.4 Thermocouples ............................... 9.4 Coolant-Salt Transfer Line 203 ...................... 9.4.1 Upper Flange on Line 203 .................... 9.4.2 Lower Flange on Line 203 .................... LO . C O W - G A S SYsllEM .......................................... 10.1 Layout and General Description ...................... 10.2 System Requirements ................................. 10.3 Flowsheet ........................................... 8.5

C e l l W a l l Penetrations f o r Lines 200 and 201 8.5.1 Reactor C e l l Sleeve 8.5.2 Anchor Sleeve 8.5.3 Shielding 8.5.4 Heaters and I n s u l a t i o n

291 291 291 292 292 297 29'7 299 300 300 308 309 309 309 310 310 311 312 312 315

315 316

318 318 319 321 322 323 323 323

325 325 325 327

.. ~

mii

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Page

. . 10.4 10.5 10.6 10.7

10.8 10.9

...................................... ............................................. ......................................... ............................... ........................

Helium Supply Dryers Preheaters Oxygen Removal Units Treated-Helium Storage Tank Bubblers f o r Indicating the S a l t Levels i n t h e Fuel and Coolant Pump Bowls Overflow Tank

......... 10.9.1 Layout and General Description ............. 10.9.2 Containment Tank ........................... 10.10 Piping, Valves, and A p p u r t e w c e s ..................

. LEAK DETECTOR SYSTEM ...................................... 11.1 Layout and General Description ..................... 11.2 Flowsheet .......................................... 11.3 Headers ............................................ 11.4 Valves .............................................

........................................ ............................... 12 . OFF'-GAS DISPOSAL S Y S " ..................................... 12.1 Layout and General Description ..................... 12.2 Flowsheet ........................................... 12.3 Holdup Volumes ..................................... 12.4 O f f - G a s Charcoal Beds .............................. 12.4.1 Main Charcoal Beds ......................... ll.5

11.6

Disconnects Local Leak Detectors

.................... Piping. Valves and F i l t e r s ......................... 12.5.1 Piping ..................................... 12.4.2

12.5

..r

Auxiliary Charcoal Beds

..................................... .................................... 12.5.3.1 Porous Metal F i l t e r i n Line 522 .. 12.5.3.2 Porous Metal F i l t e r i n Lines 524, 526, 528, and-569 .......... 13 . CONTAINMENT VENTILATION SYSTEM ............................ 13.1 Layout and General Description ..................... 13.2 Flowsheet .......................................... 13.3 Description of Equipment ........................... 13.3.1 Inlet-Air F i l t e r House ..................... 13.3.1.1 House ............................ 13.3.1.2 Heating Coils .................... 13.3.1.3 Air-Supply F i l t e r s ............... 13.3.1.4 Louvers .......................... 12.5.2 12.5.3

Valves Filters

13.3.1.5

Dampers and Ducts

................

332 332 333 334 336 337 337 338 339 344

344 349 352 353 353 355 356 359 361 368 369 369 374 376 376 376 377 377 377

383 383 387 391 391 391 392 392 392 392

xviii

.................. ................................ ................................ 13.3.4.1 Roughing F i l t e r ................ 13.3.4.2 Absolute F i l t e r s ............... 13.3.5 Stack Fans ................................ 13.3.6 Stack ..................................... 13.4 Criteria ........................................... 14. LIQUID WASTE EXslTEM ....................................... 14.1 Layout and General Description ..................... 14.1.1 Liquid Waste C e l l ......................... 14.1.2 Decontamination C e l l ...................... 14.1.3 Remote Maintenance Practice C e l l ........... 14.1.4 Sump Roon ................................. 14.2 Flowsheet .......................................... 14.3 Description of Equipment ........................... 14.3.1 Liquid Waste Storage Tank ................. 14.3.2 Waste F i l t e r .............................. 14.3.3 Waste Punrp ................................ 14.3.4 Sump Pumps ................................ 14.3.5 P i t Pump .................................. 14.3.6 J e t Pumps ................................. 14.4 Design C r i t e r i a .................................... 15 . COOLING W m R S Y S " ...................................... 15.1 Layout and General Description ..................... 15.2 Flowsheet .......................................... 15.2.1 Potable and Process Water ................. 15.2.2 Cooling Tower Water System ................ 15.2.3 Treated Water System ...................... 15.2.4 Condensate System ......................... 13.3.2 13.3.3 13.3.4

15.3

Liquid-Waste Tank Blower Vent House Filter Pit

........................... Condensate Storage Tank No . 1 ............. Condensate Storage Tank No . 2 ............. Treated Water Surge Tank ..................

Description of Equipment

15.3.1 15.3.2 15.3.3 15.3.4 15.3.5 15.3.6 15.3.7 15.3.8 15.3.9

.............................. ...................... ........... ....................... ...................................

Cooling Tower Treated Water Cooler Treated Water Circulating Pumps Cooling Tower Pumps Steam Condenser for Condensate System Space Coolers

393 393 393 393 394

394 394

396 397 397 397 397 398 398

-1

398

404 404 404 405

405 405 405 405 408 408 410 410 412 413 416 416 416 417 417 417 418 418 420 420 420

xix

Page 7

........... ................. 15.3.10 Piping. Valves and Appurtenances .......... 15.3.10.1 Piping ......................... 15.3.10.2 Valves ......................... 15.3.10.3 Backflow Preventers ............ 15.3.10.4 S t r a i n e r ....................... 15.3.11 Treated Water F i l t e r ...................... 15.3.9.1 15.3.9.2

Coolant C e l l Coolers ReacBor and Drain Tank C e l l Space Coolers

. COMPONENT COOLING SYSTEMS ................................. 16.1 General Description and Layout ..................... 16.1.1 Circulating G a s System .................... 16.1.2 Cooling Air Supply ........................ 16.2 Flowsheet ........................................... 16.3 Description of Equipment ........................... 16.3.1 G a s Blowers CCP-1 and CCP-2 and Containment Tanks ........................... 16.3.2 Air Blower, CCP-3 ......................... 16.3.3 Gas Cooler, GC ............................. 16.3.4 Valves .................................... 16.3.5 Piping .................................... 1 7. CONTAINMEXT ............................................... 1 7 . 1 General Design Considerations ...................... 17.2 Reactor and Drain Tank C e l l s ....................... 17.2.1 C e l l Leak Rate ............................ 17.2.2 C e l l Atmosphere ........................... 17.2.3 Penetrations and Methods of Sealing ....... 16

............................ 1 8 . BIOIQGICAL SHIELDING ...................................... 18.1 General Description ................................ 1 9. ELECTRICAL-mVICES ....................................... 19.1 General Description ................................. 19.2 Transmission Lines and Substation .................. 19.3 Emergency Diesel-Generators ........................ 19.3.1 Diesel-Generator Units No . 3 and N o . 4 .... 19.3.2 Diesel-Generator Unit No . 5 ............... 19.4 Process E l e c t r i c a l C i r c u i t s ........................ 17.3

Vapor Condensing System

19.4.1

Switchgear Equipment

......................

420 423 423 423 423 424 424 427 428 428 428 430 430 434 434 436 436 436 438 439 439 440

441 441 442 444 449 450 453 454 459 460 460 461 462 462

Page

19.4.1.1

............... ............ ............ ............ Motor-Control Centers ...................... 19.4.2.1 TVA Motor Control Centers ....... 19.4.2.2 Generator No. 3 Motor-Control Center ......................... 19.4.2.3 Generator No. 4 Motor-Control Center ......................... 19.4.2.4 Generator No. 5 Motor-Control Center ......................... 19.4.1.2 19.4.1.3 19.4.1.4

19.4.2

19.5

19.6

........................... 19.5.1 Building Service Panel No. 1 *.............. 19.5.2 Building Service Panel No. 2 ............... Direct-Current E l e c t r i c a l Systems ................... Battery, M - G Set and D i s t r i b u t i o n Panel 19.6.1 f o r 250-v DC System ....................... 19.6.1.1 AC-DC, 125-kw, 250-v MotorGenerator Set E-1 ............. 19.6.1.2 Battery ......................... Building Service C i r c u i t s

19.6.1.3

19.6.2

467 467 467

471 471 471 471

476 476 476 476

477

AC -E, 3-kw, Motor-Generator Sets Battery f o r 48-v System Control Panel f o r 48-v System

477 477 477

E - A C 25-kw Motor-Generator Set &E-4 and Connected Load

............................

477

.............................

479

...........................

......... ...

C i r c u i t Breaker Panels G5-l.A, G5-1C, G5-U), T2-V and T2-W

19.7.1.1 19.7.1.2

...................... Transformers G 5 - l A and G5-1C, 1 1 2 . 5 - k n ...................... Transformers G5-U), T2-V and T2-W, 75-kva C i r c u i t Breakers

...................

................ C i r c u i t Breaker Panels G5-BB, TI-A, T1-B, T1-C, T2-Y andG5-2Y ...................... 19.7.1.3

19.7.2

467

477

Heater Control C i r c u i t s

19.7.1

..............

462 465 465 465

............................

19.6.2.2 19.6.2.3 19.6.3

D i s t r i b u t i o n Panel

Battery, M-G Set and Control Panel f o r 4%-vDC System

19.6.2.1

19.7

TVA Switchgear Bus and CurrentLimiting Reactor Switchgear Bus No. 3 Switchgear Bus No. 4 Switchgear Bus No. 5

479 479 479 480 480

xxi Page

19.7.3

C i r c u i t Breaker Panels GT-2X and Drain Line 103 Heater Circuit

..................

.............. ................... 19.7.4 Heater Control Panels and Equipment ....... 19.7.4.1 Type 136 "Powerstat" ........... 19.7.4.2 Type 1256 "Powerstat" .......... 19.7.4.3 Motor-Operated Type 1256-1035 "Powerstat" ................... 19.7.4.4 Induction Regulator ............ 19.7.4,5 Three-phase 30-kva Transformer . 19,7.4.6 Single-Phase LO-kva Transformers ....................... 19.7.4.7 Heater Breaker Panels .......... 19.7.5 Heater Leads .............................. 19.8 C e l l Wall Penetrations f o r Electrical. Leads ........ 19.8.1 Sheathed Cables ........................... 19.8.2 Cable Sleeves ............................. 19.8.3 Reactor C e l l Penetration Plug and Sleeve .. 20 . BUILDING SEZLVICES ......................................... 20.1 Potable Water ...................................... 20.2 Process Water ...................................... 20.3 Building Lighting .................................. 20.4 Fencing ............................................ 20.5 S t e m Supply ....................................... 20.6 Rod, Fozmdation and Floor Drains .................. 20.7 S a n i t a r y Disposal .................................. 20.8 Air Conaitioners ................................... 20.9 F i r e Protection System ............................. APPENDIX ....................................................... L i s t of References Used i n P a r t I ......................... Abbreviations ............................................. Equipment and Location Abbreviations ...................... Symbols Used o n ,EIISRE Process Flowsheets ................... 19.7.3.1 19.7.3.2

Saturable Reactdr Special 25-kva High-Current Transformer

c /

Symbols Used i n MSRE Drawing I d e n t i f i c a t i o n Number

........

480 480 481

481 481 490 490 490 493 493 493 494 502

502 502

504 506 506 506

50% 508 508 509 509 509

509 513 515 526 529

532 534

xxiii LIST OF FIGURES Page

-Reactor Vessel i n Transport J i g P r i o r t o I n s t a l lation

iii

Construction Photograph MSRE Reactor C e l l

MSRE Flow Diagram

React o r Ve sse1

?BRE Fuel Pump

13 15

Fig.

2-1 2.2 2.3 2.4 2.5 2-6 3.1 3.2 3.3 3.4 3.5

Fig.

4.1

Front View of Building 7503

Fig.

4.2

Rear View of Building 7503 During MSRE: Construction

Fig.

4.3

Plan a t 852-ft Elevation

Fig.

4.4

Plan a t &$O-Pt Elevation

Fig.

Elevation Building 7503 ,

Fig.

4.5 4.6

Shield Block Arrangement a t Top of Reactor C e l l

41 45

Fig.

4.7

Block Arrangement on Top of Drain Tank C e l l

Fig.

5.1

Reactor C e l l Plan

Fig.

Reactor C e l l Elevation

Fig.

5.2 5.3

Fuel-Salt System Process Flowsheet

Fig.

5.4

Cross Section MSRE Reactor Vessel and Access Nozzle

Fig.

Elevation of Control Rod Drive Housings

Typical Graphite S t r i n g e r Arrangement

Fig.

5;5 5.6 5.7

L a t t i c e Arrangement a t Control Rods

Fig.

5.8

Graphite-INOR-8 Sample Assembly

Fig.

5.9

Full-scale Model of Reactor Vessel

Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig. Fig.

Fig.

Primary Heat Exchanger Fuel-Salt Drain Tank

16 18

ORNL Area Map

P l o t Plan Molten S a l t Reactor Experiment Building 7503

Potable Water Supply t o MSRE E l e c t r i c a l Distribution System t o MSRE

31 33

Steam Supply t o MSRE

34 36 37 39 40

Radiator Coil and Enclosure

xxiv Page Fig. 5.10 Pressure Drop Through Reactor Core Fig. 5.11 Centerline Velocity Distribution in Volute of MSRE Full-scale Model of Core Fig. 5.12 Flow Distribution in Reactor Core Fuel Passages at Total Flow Rate of 1200 gpm in Full-Scale Model Fig. 5.13 Control Rod Poison Element Fig. 5.14 Control Rod and Drive Assembly Fig. 5.15 Diagram of Control Rod Drive

94 95 99

108 109 111

Schematic of Reactor Access Shown Ready for Removal of Specimen Assembly

115

Fig. 5.17 Work Shield for Graphite Sampler Fig. 5.18 Criteria for Establishing Static Design Stresses in INOR-8

117

Fig. 5.19 Reactor Vessel H a n g e r Rods Fig. 5.20 Thermal Shield Prior to Installation

123

Fig. 5.16

Fig. 5.21 Fig. 5.22

Exterior View of Fuel Pump Showing Flange Bolt Extensions Fuel-Salt PLmrp Bridge and Impeller Seal Clearances

Fig. 5.23

Lubricating Oil System Flowsheet

120

126 134

140 145

Fig. 5.24 Hydraulic Performnce of Fuel hurrp

150

Fig. 5.25

156

Fig. 5.26 Fig. 5.27

Fuel hurrp Support Fuel Pump Overflow Tank

h-imary Heat Exchanger Subassemblies Fig. 5.28 Tube to Tube-Sheet Joint in MSRE Primary Heat Exchanger Fig. 5.29

Freeze Flange and Clamp

Fig. 5.30 Freeze Flange Clamping Frame Showing Assembly and Disassembly Fig. 5.31 Freeze Valve and Line 103 Fig. 5.32 Freeze Valve and Lines 107, 108, 109, 110

159

163 167

179 185

Fig. 6.1

Fuel Drain Tank System Process Flowsheet

195 199 200 202 204 223

Fig. 6.2

Fuel Processing System Flowsheet

227

Fig. 5.33

Freeze Valve and Lines 111 and 112

Fig. 5.34

Freeze Valve and Lines 204 and 206 Remonble Heater for %in. Pipe

Fig.

5.35

Page Fig. 6.3: Fig, 6.4

7.1 Fig. 7.2 Fig. 7.3 Fig.

Fig. 7.4 Fig. 7.5 Fig. 7.6 Fig.

7.7

Fig. 8.1 Fig. 8.2

8.3 8.4 8.5 8.6 8.7 Fig. 8.8 Fig. Fig. Fig. Fig. Fig.

Fig. 8.9 Fig. 10.1 Fig. 10.2 Fig. 10.3 Fig. ll.1 Fig. 11.2 Fig. 11.3 Fig. 11.4 Fig. 11.5 P I

Fig. 12.1 Fig. 12.2

Fuel Drain Tank Steam Dome Bayonet Assembly Bayonet Cooling Thimble for Fuel Drain Tank Sampling (left) and Enriching (right) Capsules Sampling Capsule Cable Latch Schematic Representation Fuel-Salt SarrrplerEnricher Dry Box Capsule Access Chamber Transfer Cask for Sampler-Enricher Transport Container Effect of Thickness on Effectiveness of Sampler Shielding Flow Diagram of Cover-Gas, Off-Gas and Leak Detection Systems for Sanrpler-Enricher Coolant-Salt System Process Flowsheet Performance Curves for Coolant-Salt Pump Radiator Coil Configuration Radiator Tube Matrix Radiator Tube Supports Characteristics of Radiator Duct Annulus Fans Radiator Air Flow Characteristics Radiator Air Flow Characteristics at Various Steps in Load Regulation Est-ted Performance of Both Wdiator Supply Air Fans Operating in Parallel Flow Diagram of Cover-Gas System Cover-Gas System Process Flowsheet Oxygen Removal Unit Cover-Gas System General Routing of Leak Detector Lines Schematic Diagram of Leak-Detected Flange Closure Method 09 Utilizing One Leak Detector Line to Serve Two Flanges in Series Leak Detector System Process Flowsheet Leak Detector System Block Disconnects with Yoke Schematic Diagram of Off-Gas System Off-Gas System Process Flowsheet

231

232

248 251 253

257 265

268

270 280 290 293 294 295 301 303 304 306

326

328 335 346 347 348

350 354 360 363

Page Fig. 12.3

Activity of Fission-Product Isotopes of Xenon and Krypton In hunp Bowl Off-Gas

370

Fig. 12.4

Estimated Charcoal Bed Temperatures as Function of Flow Rate Through the Bed

371

Fig. 12.5

Concentration of Xenon and -ton at Off-Gas Stack Outlet Maximum Estimated Temperature in First Section of Charcoal Bed vs Pipe Diameter

372

Fig. 12.7 Fig. 13.1

Porous Metal Filter in Off-Gas Line 522 Schematic of Air Flow Diagram Containment Ventilation System

381. 385

Fig. 13.2

Stack Fan Performance Curves Liquid Waste System Process Flowsheet Cooling Water System Process Flowsheet Characteristic Curves Treated Water Circulating

395

Fig. 12,6

Fig. 14.1 Fig. 15.1 Fig. 15.2 Fig. 15.3

pumps Characteristic Curves - Cooling Tower Water Circu-

375

399 411

419 421

lating Pumps Fig. 15.4

Cross Section Backflow Preventers in Water Lines

425

819 and 890

Fig. 15.5 Fig. 17.1 Fig. 19.1

Capacity of Backflow. Preventers in Water System Diagram of MSRE Vapor-Condensing System Simplified One-Line Diagram of Electrical Supply System

Fig. 19.2

Process Equipment Electrical Distribution System

Fig. 19.3

Building Services Electrical Distribution System

456 458

Fig. 19.4

Location of Equipment in Switch House

463

Fig. 19.5

Typical Schematic Diagram for Type 136 Powerstat

482

Fig. 19.6

Typical Schematic Diagram for Type 1256-1035 Powerstat Motor-Operated

491

Fig. 19.7

Motor-Operated Induction Regulator

Fig. 19.8

Male and Female Electrical Disconnects for Heater Leads Inside Cells

492 495

Fig. 19.9

Typical Electrical Lead Penetration of Reactor Cell Wall Water Services to Building 7503

Fig. 20.1

426

445 455

505 507

xxvii

r 4,

Page Fig. 20.2

Schematic Diagram Building 7503 Drainage System

510

Fig. A . 1

Symbols Used on MSRE Process Flowsheets Symbols Used on MSRE Process Flowsheets

532

Fig.

A.2

533

UST OF TABUS Page -Table

2.1

Composition and Physical P r o p e r t i e s of t h e Fuel, Flush, and Coolant S a l t s

Table

2.2

Composition and P r o p e r t i e s of INOR-8

Table

2.3

R e a c t i v i t y Requiremnts

Table

4.1

Reactor C e l l Penetrations

Table

4.2

Drain Tank C e l l Penetrations

Table

4.3

Auxiliary C e l l Dimensions

Table

5.1

D i s t r i b u t i o n of H e l i u m Supply t o Fuel Pump

Table

5.2

Reactor Vessel and Core Design Data and Dimensions

Table

5.3

P r o p e r t i e s of MSRF: Core Graphite

Table

5.4

Summary of Reactor Physics Data

87 101

Table

5.5

Fuel-Salt Circulation Pump Design Data

135

Table

5.6

Lubricating-Oil System Design Data

146

Table

5.7

Lubricating O i l P r o p e r t i e s

148

Table

5.8

Estimated S t r e s s e s i n MSRE Fuel-Pump Shaft ( p s i )

153

Table

5.9

Design Data f o r Primary Heat Exchanger

164

Table

5.10

Variable Spring Supports f o r Fuel and Coolant-Salt Piping I n s i d e Reactor Cell

- CGB

Table

5.11 MSRE Freeze Valves

177 191

Table

5.12

MSRE Pipe Line Heaters

209

Table

5.13

Thermal I n s 7 d a t i o n on Major MSRF: Salt Piping

216

Table

6.1

Design Data f o r Drain Tanks No. 1 and 2

229

Table

6.2

Design Data f o r Condensers i n Drain Tank Heat Removal Systems

236

Table

6.3

Design D a t a f o r Fuel System Flush S a l t Tank

241

Table

6.4

Salt Transfer Pipe Line Supports

243

Table

7.1

3elim Supply Lines and R e s t r i c t o r s i n Fuel-Salt Sampler-Enriche r System

272

Table

8.1

Coolant-Salt C i r c u l a t i n g Pump

286

Table

8.2

Radiator Design Data

296

Table

8.3

Possible Steps f o r Controlling Heat Removal Rate from t h e Radiator

307

Page Table

8.4

Coolant C e l l S a l t Piping Supports

314

Table

9.1

Design Data f o r Coolant-Salt Drain Tank

320

Table 1 0 . 1

Cover G a s System Hand Valves

340

Table 10.2

Cover G a s System Check Valves

341

Table 10.3

Cover Gas System Control Valves and Regulators

342

Table ll.l

351 357

Table 12.2

Leak Detector System Headers Design Data O f f - G a s Disposal System Atom Flow Rate Emerging from Fuel Pump Bowl

Table 12.3

Off-Gas System Air-Dperated Valves

378

Table 12.4

Off-Gas System Check Valves

379

Table 12.5

O f f -Gas System Hand Valves

380

Table 13.1

Estimated Containment Ventilation System A i r Flow Rates During Normal Reactor Opemtions (cf’m)

384

Table 1 4 . 1

Lines Emptying i n t o Sump i n Room

403

Table 14.2

Sump Ejector C h a r a c t e r i s t i c s

406

Table 1 5 . 1

Equipment Cooled by Cooling Tower Water

409

Table 15.2

Equipment Cooled by Treated Water

409

Table 15.3

Design Data Beactor and Drain TakiK C e l l Space Coolers

422

Table 16.1

Gas-Cooled Components

429

Table 16.2

A i r -Cooled Component s

431

Table 16.3

Component Cooling System Valves

437

Table 19.1

Switchgear Bus and Breaker Data

464

Table 19.2

Connections t o Switchgear Bus No. 3

466

Table 19.3

Equipment Connections t o TVA Motor Control Centers

468

Table 19.4

Equipment Connections t o Motor Control Center G-3

469

Table 19.5

Equipment Connections t o Motor Control Center G-4

470

Table 19.6

Equipment Connections t o Motor Control Centers G-5-1 and G-5-2

472

Table 19.7

Connections t o Building Service Panel No. 1

473

Table 19.8

Connections t o Lighting Distribution Panels IA and I A l

Table 12.1

Table 19.9

Connections t o Building Service Panel No. 2

Table 19.10 Heater Control Panels

373

474 475 483

Table 19.11 Heater E l e c t r i c a l Lead C e l l W a l l Penetrations Table 19.12

Summary of E l e c t r i c a l Lead Penetrations i n Reactor Cell

Summary of E l e c t r i c a l Lead Penetrations i n Drain Tank C e l l Table 19.14 General Cable Company MI Cable Numbers

496 503

Table 19.13

503 503

b w),

MOLTEN-SALT REACTOR EXPERIMENT

PART I DESCRIPTION OF REACTOR DESIGN

Volume I

3 1.

INTRODUCTION

The Molten-Salt Reactor Experiment (MSRE) was undertaken by the

Oak Ridge National Laboratory t o demonstrate t h a t t h e desirable f e a t u r e s of t h e molten-salt concept could be embodied i n a p r a c t i c a l r e a c t o r t h a t could be constructed and maintained without undue d i f f i c u l t y and one t h a t could be operated s a f e l y and r e l i a b l y .

Additional important objectives

were t o provide t h e f i r s t large-scale, long-term, high-temperature t e s t s

i n a r e a c t o r environment of t h e f u e l s a l t , graphite, moderator, and highnickel-base a l l o y (INOR-8). Operating data from t h e MSRF: should provide important information regarding t h e f e a s i b i l i t y of large-scale moltens a l t reactors

Molten-salt r e a c t o r s were f i r s t investigated a s a means of providing a compact high-temperature power plant f o r nuclear-powered a i r c r a f t .

1954 an A i r c r a f t Reactor Experiment (ARE) was constructed a t ORNL which demonstrated t h e nuclear f e a s i b i l i t y of operating a molten-salt-fueled r e a c t o r a t high temperature.

Fuel entered t h e ARE core a t 120OoF and

l e f t a t 15OO0F when t h e r e a c t o r power l e v e l was 2.5 Mw. Immediately a f t e r the successful operation of t h e ARE, t h e A i r c r a f t Reactor Test (ART) was s t a r t e d a t ORNL a s p a r t of t h e A i r c r a f t Nuclear Propulsion Program (ANP). This t e s t was discontinued i n 1957 when t h e ANP Program was revised, but t h e high promise of t h e molten-salt r e a c t o r type f o r achieving low e l e c t r i c power generating c o s t s i n c e n t r a l power s t a t i o n s l e d ORNL t o continue p a r t s of t h e b a s i c study programs.

Features

of t h e molten-salt concept which deserve s p e c i a l mention w i t h regard t o i t s f u t u r e propects are:

The f u e l i s f l u i d a t r e a c t o r temperatures, thus eliminating t h e

e x t r a c o s t s associated w i t h t h e f a b r i c a t i o n , handling, and reprocessing of s o l i d f u e l elements.

Burnup i n t h e f u e l i s not l i m i t e d by r a d i a t i o n

damage o r r e a c t i v i t y loss.

The f u e l can be reprocessed continuously i n

a s i d e stream f o r removal of f i s s i o n products, and new f i s s i o n a b l e mat e r i a l can be added while t h e r e a c t o r i s i n operation.

Molten-salt r e a c t o r s can operate a t high temperatures and pro-

duce high-pressure superheated steam t o achieve thermal e f f i c i e n c i e s i n t h e heat-power cycle equal t o t h e b e s t f o s s i l - f u e l - f i r e d p l a n t s .

The

r e l a t i v e l y low vapor pressure of t h e s a l t permits use of low pressure containers and piping

The negative temperature c o e f f i c i e n t of t h e r e a c t o r and t h e

low excess r e a c t i v i t y a r e such t h a t t h e nuclear s a f e t y i s not primarily dependent upon fast-acting control rods.

The fuel s a l t has a low cross section f o r t h e p a r a s i t i c ab-

sorption of neutrons, and when used w i t h bare graphite as t h e moderator, very good neutron economies can be achieved.

Molten-salt r e a c t o r s a r e

thus a t t r a c t i v e as highly e f f i c i e n t converters and breeders on t h e Th-.?34J cycle.

5 . The fluoride salts used as t h e f l u i d f u e l mixture have good thermal and r a d i a t i o n s t a b i l i t y and do not undergo v i o l e n t chemical r e actions w i t h water o r a i r .

They a r e compatible w i t h t h e graphite moder-

a t o r and can be contained s a t i s f a c t o r i l y i n a s p e c i a l l y developed highn i c k e l alloy, INOR-8. The volumetric heat capacity, viscosity, thermal conductivity, and other physical properties are a l s o within desirable ranges.

U s e of r e l a t i v e l y high c i r c u l a t i o n rates and temperature d i f -

ferences r e s u l t s i n high mean power density, high s p e c i f i c power, and low f u e l inventory. These a t t r a c t i v e features of t h e molten-salt r e a c t o r concept are p a r t i a l l y o f f s e t by t h e disadvantages that: 1. The f u e l salt mixture melts a t about 840°F, so means must be

provided f o r maintaining a l l salt-containing portions o f t h e system above t h i s temperature. 2.

The f l u o r i d e salts r e a c t with oxygen t o p r e c i p i t a t e f u e l con-

s t i t u e n t s as oxides.

Although zirconium t e t r a f l u o r i d e i s included i n

t h e salt mixture so that ZrO w i l l p r e c i p i t a t e i n preference t o U02, care 2 must be taken t o prevent t h e f u e l from being contaminated with a i r , water,

o r other oxygen-containing materials.

The r a d i o a c t i v i t y i n any f l u i d - f u e l system i s i n a mobile form,

and s p e c i a l provisions must be taken f o r containment and maintenance.

During the period 195”(-60, investigations were carried out at OWL on the fuel salt chemistry, metallurgy of containment materials, the design of salt-circulating pumps, and on remote maintenance techniques. The results ofthis work lent additional encouragement, and in 1959 studies 2 were made by H. G. MacF’herson’ and L. G. Alexander et al. pertaining to the applicability of the molten-salt concept to central power station reactors. The studies resulted in a proposal3 to the AEC for construction

of a molten-salt experiment to investigate remaining areas of uncertainty that could be resolved only by actually building and operating a moltensalt reactor. In April, 1961, ORNL received a directive4 from the AEC to design, construct, and operate the Molten-Salt Reactor Experiment (MSRE ), the subject of this report. Early in the design phases it was decided that the MSRE was to have as its primary purpose the investigation of the practicality of the molten-

salt concept for central power station applications. As such, the MSRE

was envisioned as a straightforward-type of installation, uncomplicated by the inclusion of experimental apparatus which might jeopardize reliable, long-term operation. It was a l s o necessary that the MSRE be of a largeenough capacity for the experimental findings to be meaningfully extrapolated to the full-scale plants. It was decided that a reactor of 10 MW thermal output would satisfy the criterion. Conversion of the 10 Mw of heat to useful electricity was not considered t o be n e c e s s a r y t o demonstrate the concept, so e x i s t i n g blowers

and stack were used to dissipate the heat to the atmosphere. Containment requirements dictated a double barrier between the highly radioactive fuel salt and the environment, and a salt very similar to the fie1 salt in composition and physical properties was chosen to transport the heat from the fuel salt to air-cooled surfaces.

An expanded plant layout was adopted in order to provide access to equipment and to facilitate maintenance operations, The MSRE was installed in an existing building in the 7503 Area at ORNLthat was constructed specifically for the AFU3 and ART.

This arrangement provided some savings and

expedited construction in that the building included a containment vessel which, with modification, was suitable for the ERE. A significant amount of usable auxiliary equipment was also on hand, including air blowers and

6 a s t a c k f o r d i s s i p a t i o n o f heat t o t h e atmosphere, emergency d i e s e l -

e l e c t r i c power supply, heavy-duty cranes, e t c .

Shop, office, washroom,

and control room spaces were a l s o available, and some o f t h e heavy conc r e t e shielding was adaptable t o t h e MSRE.

F i t t i n g t h e MSRE design t o

t h e e x i s t i n g f a c i l i t i e s required numerous design compromises, but no ex-

treme d i f f i c u l t i e s were encountered. Construction of t h e MSRE o f f i c i a l l y s t a r t e d i n July, 1961, although

much of t h e advance thinking and preliminary design work were well under way by that time.

Major building modifications were s t a r t e d i n 1961 and

were completed by t h e end of 1962.

Iack of funds and l a t e d e l i v e r y of

t h e graphite moderator delayed i n s t a l l a t i o n of major equipment u n t i l e a r l y

1964. The i n s t a l l a t i o n was scheduled f o r completion i n t h e e a r l y summer of 1964, and t h e t a r g e t date t o achieve c r i t i c a l i t y was s e t f o r t h e end o f t h a t year.

- w

GEKERAL DESCRIPTION

2.1

Type

The Molten-Salt Reactor Experiment ( E R E ) i s a single-region, unclad, graphite-moderated, f l u i d - f u e l type of r e a c t o r w i t h a design.heat generation r a t e of 10 Mw.

The c i r c u l a t i n g f u e l i s a mixture of lithium,

beryllium, and zirconium f l u o r i d e salts t h a t contains uranium o r thorium and uranium f l u o r i d e s .

Reactor heat i s t r a n s f e r r e d from t h e f u e l s a l t

t o a s i m i l a r coolant s a l t and i s then dissipated t o t h e atmosphere.

.,.

2.2. Location

The Ekperiment i s located i n t h e 7503 Area of t h e Oak Ridge National Iaboratory, Oak Ridge, Tennessee.

The s i t e i s about one-half

mile south of t h e main Laboratory buildings, i n a wooded, secluded bend of t h e Clinch River t h a t i s reserved f o r s p e c i a l r e a c t o r i n s t a l l a t i o n s . 2.3

Fuel and Coolant S a l t s

The composition and physical properties o f various f u e l and coolant salts a r e given i n Table 2.1.

Favorable neutron absorption and chemical

and physical properties were important requirements f o r t h e compositions selected.

Beryllium f l u o r i d e i s used t o obtain a low melting p o i n t .

L i t h i u m f l u o r i d e (99.99% Li7 i n both f u e l and coolant s a l t s ) imparts

good f l u i d flow properties t o t h e mixture.

Zirconium fluoride p r o t e c t s

t h e f u e l s a l t against p r e c i p i t a t i o n of U02 *om

contamination by a i r and

moisture. Fuel salts containing throium a r e o f i n t e r e s t for future l a r g e s c a l e thorium breeder r e a c t o r s .

The first experiments i n t h e MS-

will

be run with p a r t i a l l y enriched uranium because t h e r e a r e fewer uncert a i n t i e s concerning t h e chemical behavior of t h a t f u e l .

Later t h e

r e a c t o r w i l l be operated with t h e highly enriched uranium f u e l and then with t h e thorium-uranium f u e l .

Table 2.1

Composition and Physical Properties of the Fuel, Flush, and Coolant S a l t s 5 Fuel S a l t Thorim Uranium

Highly Enriched Uranium

P a r t i a l l y Enriched Uranium

Flush and Coolant S a l t

66.8

29.1

ZrF4

70 23.6 5

Tm4

0.4

0.2

0.9

1200"F

1060"F

Density, l b / f t 3 , a t 1200°F

140

130

134

120

Viscosity, l b / f t - h r Heat Capacity, Btu/lb- "F

0.45 ( a t 1200 "F )

0.48

0.47

0.53 ( a t 1200"F )

3.21 840

3- 2

3.2

3.5

840

850

Composition, mole LiF (99.994 L i 7 ) BeF2

Physical Properties, a t

Thermal Conductivity, Btu/hr2 ("F/ft) Liquidus Temperature, "F

2.4

Equipment and Process

The major items of equipment i n t h e MSRE a r e shown on a simplified flowsheet i n Fig. 2.1. primary system.

The f'uel-salt-circulating system i s t h e r e a c t o r

It c o n s i s t s of t h e r e a c t o r v e s s e l where t h e nuclear

heat i s generated, t h e f u e l heat exchanger i n which heat i s t r a n s f e r r e d from f u e l t o coolant, t h e f u e l c i r c u l a t i n g pump, and t h e interconnecting piping.

The coolant system i s t h e r e a c t o r secondary system.

c o n s i s t s of t h e coolant pump, a r a d i a t o r i n which heat i s t r a n s f e r r e d from coolant s a l t t o a i r , and t h e piping between t h e pump, t h e r a d i a t o r , and t h e f u e l heat exchanger.

There a r e a l s o drain-tank systems f o r con-

t a i n i n g t h e f u e l and coolant s a l t s when t h e c i r c u l a t i n g systems a r e not i n operat i o n . 2.4.1

Reactor The r e a c t o r v e s s e l i s a 5-f't-diam by 8-f't-high tank t h a t contains

a 33-in.-diam

by 64-in.-high graphite core s t r u c t u r e .

ing o f t h e r e a c t o r i s shown i n Fig. 2.2.

A cutaway draw-

Under design conditions of

10 Mw of r e a c t o r heat, t h e f'uel s a l t e n t e r s t h e flow d i s t r i b u t o r a t t h e

top of t h e v e s s e l a t 1175OF and 20 p s i g .

The f u e l i s d i s t r i b u t e d evenly

around t h e circumference of t h e v e s s e l and then flows t u r b u l e n t l y downward i n a s p i r a l path through a l - i n . annulus between t h e v e s s e l w a l l and t h e core can.

The wall o f t h e v e s s e l i s thus cooled t o within about

5 O F o f t h e bulk temperature o f t h e entering s a l t .

The salt loses i t s

r o t a t i o n a l motion i n t h e straightening vanes i n t h e lower plenun and

turns and flows upward through t h e graphite matrix i n t h e core can. The graphite matrix i s an assembly of v e r t i c a l bars, 2 i n . by 2

i n . by about 67 i n . long.

Fissioning of 23% i n t h e f u e l occurs a s it

flows i n 0.4-in. by 1.2-in. channels that a r e formed by grooves i n t h e s i d e s o f t h e bars. There are about 1140 of t h e s e passages. The nominal core volume within t h e ??-in.-diam by @-in.-high core

3 , of which 20 f% 3 i s f'uel and 70 f't 3 i s graphite.

s t r u c t u r e i s 9 f't

A t 10 Mw, and with no f u e l absorbed by t h e graphite,

generated i n t h e f u e l outside t h e nominal core,

-'w

1.4 Mw of heat i s

0.6 Mw i s generated i n

t h e graphite, and 8.0 Mw i s generated i n t h e f u e l within t h e core.

This

UNCLASSIFIED

OWL-Dwc 634209R

F i g . 2.1.

MSRE Flow Diagram.

UNCLASSIFIED ORNL-LR-DW 6109711

SAMPLE ACCESS POR

FLEXIBLE CONDUIT TO CONTROL ROD DRIVES

COOLING AIR LINES

ACCESS PORT COOLING JAC KETS FUEL OUTLET

REACTOR ACCESS PORT

CONTROL ROD THIMBLES

CENTERING GRI

FLOW DISTRIBUTOR

REACTOR CORE CA REACTOR VESSE

ANTI-SWIRL VANES VESSEL DRAIN L I N E

Fig. 2.2.

Reactor Vessel.

corresponds t o an average f u e l power d e n s i t y of 14 kw/liter i n t h e nominal

The maximum f u e l power d e n s i t y i s 31 kw/liter.

core.

Flow i n t h e coolant channels i s l a m i n a r , but both t h e graphite and t h e f u e l have good thermal conductivities, so t h e maximum temperature of t h e graphite i s only about 60°F above t h e mixed mean temperature of t h e adjacent f u e l .

The nuclear average and t h e maximum temperatures, respec-

t i v e l y , of t h e graphite are estimated t o be about l255'F

and 1300°F.

The

temperature of t h e f i e 1 leaving t h e h o t t e s t channel i n t h e core i s about 1260'F. Fuel leaves t h e top o f t h e r e a c t o r a t 1225'F

and 7 p s i g through t h e c

s i d e o u t l e t of a s p e c i a l f i t t i n g designed as an access p o r t f o r i n s e r t i o n of graphite and metal samples and f o r t h r e e 2-in.-diam control rod thimbles. The poison elements i n t h e c o n t r o l rods a r e short hollow cylinders of gadolinium oxide 1 i n . i n diameter, clad with Inconel and arranged on a f l e x i b l e Inconel hose t o permit passage through two bends t h a t form an o f f s e t i n each thimble.

The c o n t r o l rods and drives a r e cooled by c i r c u -

l a t i o n of c e l l atmosphere through t h e f l e x i b l e hoses and thimbles. A 1-1/2-in.-diam

o u t l e t l i n e i s provided a t t h e bottom of t h e r e a c t o r

vessel f o r discharging salt t o t h e d r a i n tanks. 2.4.2

Fuel Pump The f u e l s a l t f r o m t h e r e a c t o r flows d i r e c t l y t o t h e c e n t r i f u g a l

sump-type pump shown i n Fig. 2.3.

The pump has a v e r t i c a l shaft and

overhung impeller and operates a t a speed of 1160 rpm t o d e l i v e r 1200 gpm a t a discharge head of 49 f't.

The pump bowl i s about 36 i n . i n d i -

amter, and t h e purrrp and 75-hp motor assembly i s about 8 ft high. Devices are provided i n t h e pump bowl t o measure t h e l i q u i d l e v e l as a means of determining t h e inventory of s a l t i n t h e system.

Small

capsules can be lowered i n t o t h e bowl t o take a 10-g sample of s a l t f o r a n a l y s i s o r t o add 120 g of m e l t 0 t h e system.

About 65 gpm of t h e

pump out-put i s c i r c u l a t e d i n t e r n a l l y t o t h e pump bowl f o r r e l e a s e o f ent r a i n e d o r dissolved gases f r o m t h e s a l t . Helium flows through t h e gas space i n t h e bowl a t a r a t e of about 200 f't 3/day ( S T P ) t o sweep t h e highly radioactive xenon and krypton t o t h e off-gas disposal system. clude a i r and water vapor.

The helium a l s o a c t s as a cover gas t o ex-

UNCLASSIFIED ORNL-LR-DWG-56043-BR

FIG. 2.3. MSRE FUEL PUMP

14 The pump i s equipped with b a l l bearings t h a t a r e lubricated and cooled with o i l circulated by an e x t e r n a l pumping system.

The o i l i s

confined t o t h e bearing housing by mechanical s h a f t s e a l s .

A helium

purge enters below t h e lower s e a l .

A small p a r t of t h i s helium flows up-

ward along t h e s h a f t and leaves j u s t below t h e lower s e a l , carrying with

it any o i l vapors t h a t l e a k through t h e seal.

The remainder flows down-

ward along t h e s h a f t t o t h e pump bowl and subsequently t o t h e off-gas system.

This prevents radioactive gases from reaching t h e o i l .

Cooling o i l i s a l s o c i r c u l a t e d through a metal block above t h e pump bowl which s h i e l d s t h e l u b r i c a t i n g o i l and the pwlrp motor.

The motor and t h e bearing s h a f t and impeller assembly a r e remova-

b l e separately t o f a c i l i t a t e maintenance. An overflow tank of 5.5-f't 3 volume i s i n s t a l l e d below t h e pump t o 4

provide s u f f i c i e n t volume for f r e e expansion of s a l t under a l l foreseen conditions 2.4.3

Heat &changer

S a l t discharged by t h e f u e l pump flows through t h e s h e l l s i d e of t h e horizontal shell-and-tube heat exchanger shown i n Fig. 2.4, where

it i s cooled from l225'F t o ll75OF. The exchanger i s about 16 i n . i n diameter and 8 ft long and contains one hundred sixty-three 1/2-in.-OD U-tubes with an e f f e c t i v e surface of 259 f t2 The coolant s a l t circu-

l a t e s through t h e tubes a t a r a t e of 8% gpm, entering a t 1025'F

and

leaving a t UOOOF. 2.4.4

Coolant Pump The coolant s a l t i s c i r c u l a t e d by a c e n t r i f i g a l pump i d e n t i c a l i n

most respects t o t h e f u e l pump.

The pump has a 75-hp, l75O-rpm motor

and d e l i v e r s 850 g p m against a head of 78 ft. 2.4.5

Radiator The r a d i a t o r i s shown i n Fig. 2.5.

Seven hundred square feet of

cooling surface i s provided by 120 tubes 0.75 i n . i n diameter by 30 t'f long.

Cooling a i r i s supplied t o t h e r a d i a t o r by two 2%-hp a x i a l

blowers with a combined capacity of 200,000 cf'm. a t o r a t llOO°F and leaves a t 1025'F. is 200°F a t design power.

S a l t enters the radi-

The temperature r i s e of t h e a i r

To guard against freezing t h e s a l t i n t h e

UNCLASSIFIED

ORNL-LR-WG 5203612

FUEL INLET

1/2-in.-OD TUBES

'd c

CROSS BAFFl.ES THERMAL-BARRIER PLATE

46.4-in. OD II 0.2-in. WALL x 8 - f t LONG

COOLANT-STREAM SEPARll,XING BAFFLE

COOLANT OUTLET

FUEL OUTLET

Fig. 2.4.

Primary Heat Exchanger.

UNCLASSIFIED ORNL-LR-DWG 55841R2

Fig. 2.5.

Radiator Coil and Enclosure.

17 r a d i a t o r tubes on sudden reduction of r e a c t o r power, quick-closing doors a r e provided t o shut o f f t h e a i r flow, and t h e r a d i a t o r i s heated by e l e c t r i c a l heaters inside t h e enclosure.

The opening of t h e doors can

be adjusted, and some of t h e a i r can be bypassed around t h e r a d i a t o r t o regulate t h e heat removal r a t e . 2.4.6

Drain Tank Systems

Four tanks a r e provided f o r s a f e storage of t h e s a l t mixtures when they a r e not i n use i n t h e f u e l - and coolant-salt c i r c u l a t i n g systems. Two f u e l - s a l t d r a i n tanks and a f l u s h - s a l t tank a r e connected t o the

r e a c t o r by means of t h e fill and drain l i n e .

One drain tank i s provided

f o r t h e coolant s a l t . A f u e l drain tank i s shown i n Fig. 2.6.

The tank i s

in. in

diameter by 86 i n . high and has a volume of about 80 f t 3, s u f f i c i e n t t o hold i n a n o n - c r i t i c a l geometry a l l t h e s a l t that can be contained i n t h e f u e l c i r c u l a t i n g system.

The tank i s provided with a cooling

system capable of removing 100 kw of fission-product decay heat, t h e cooling being accomplished by b o i l i n g water i n 32 bayonet tubes t h a t a r e i n s e r t e d i n thimbles i n t h e tank. The f l u s h - s a l t tank i s s i m i l a r t o t h e f u e l - s a l t tank except t h a t it has no thimbles or cooling system.

New f l u s h s a l t i s l i k e f u e l s a l t

but without f i s s i l e or f e r t i l e material.

It i s used t o wash t h e f u e l

c i r c u l a t i n g system before f u e l i s added and a f t e r f u e l i s drained, and t h e only decay heating i s by t h e small q u a n t i t y o f f i s s i o n products t h a t it removes from t h e equipment. The coolant-salt tank resembles t h e f l u s h - s a l t tank, but it i s 40 i n . i n diameter by 78 i n . high and t h e volume i s 9 f% 3

The tanks are provided with devices t o i n d i c a t e high and low l i q u i d l e v e l s and with weigh c e l l s t o i n d i c a t e t h e weight of t h e tanks and t h e i r contents. 2.4.7

Piping and Flanges The major components i n t h e s a l t c i r c u l a t i n g systems a r e i n t e r -

connected by 5-in. sched-40 piping.

Flanged j o i n t s between u n i t s i n

t h e primary system f a c i l i t a t e removal and replacement of components by remotely operated t o o l s .

These flanges, c a l l e d freeze flanges, u t i l i z e

18 WUASSIFIED OWL-LR-DWG 617t9

INSPECTION, SAMPLER, AND LEVEL PROBE ACCESS

FUELSALTSYSTEM

FILL AND DRAIN UM

TANK FILL LINE

Fig. 2.6.

Fuel-Salt Drain Tank.

a frozen salt s e a l between t h e flange faces a s well as a conventional 0-ring-type j o i n t t o form a helium-buffered,

leak-detected type of

closure. The f i l l and drain l i n e s are 1-1/2-in.

sched-40 piping and contain

t h e only "valves" t h a t come i n contact with salt.

The valves, c a l l e d

freeze valves, have no moving p a r t s , unmodulated flow control being achieved by freezing or thawing salt i n a short, p a r t i a l l y f l a t t e n e d section of pipe t h a t can be heated and cooled. 2.4.8

Heaters

A l l p a r t s of t h e salt-containing systems are heated e l e c t r i c a l l y t o maintain t h e s a l t s above the liquidus temperature of 840 t o 85OoF. The equipment i s preheated before salt i s added and t h e heaters a r e energized continuously during r e a c t o r operation t o make sure t h a t t h e r e

i s no uncontrolled freezing i n any of t h e piping and t h a t t h e salt can be drained when necessary.

The t o t a l capacity of t h e h e a t e r s i s about

1930 kw, but t h e a c t u a l power consumption i s somewhat l e s s than h a l f of t h i s .

About 300 kw of heat can be provided by t h e d i e s e l e l e c t r i c

emergency power supply.

2.4.9

Materials The salt-containing piping and equipment a r e made of INOR--a

s p e c i a l high-nickel and molybdenum a l l o y having a good r e s i s t a n c e t o a t t a c k by f u e l and coolant s a l t s at temperatures a t l e a s t as high as

1500%.

The mechanical p r o p e r t i e s a r e superior t o those of many austen-

i t i c stainless s t e e l s , and t h e a l l o y i s weldable by established procedures.

The chemical composition and some of t h e physical p r o p e r t i e s

Most of t h e INOR equipment was designed f o r 13OO0F and 50 psig, w i t h an allowable s t r e s s of 2750 p s i , w e given i n Table 2.2.

S t a i n l e s s s t e e l piping and valves were used i n t h e helium supply and i n t h e off-gas systems. 2.4.10

Cover- and O f f - G a s Systems

A helium cover-gas system p r o t e c t s t h e oxygen-sensitive f u e l from

contact with a i r o r moisture.

b, ??

Commerical helium i s suppled i n a tank

truck and i s passed through a p u r i f i c a t i o n system t o reduce t h e oxygen and water content below 1 ppm before it i s admitted t o t h e reactor.

Table 2.2. Compos tion and Properties of LNOR-~ Chemical Properties:

66-71$

1.0%

15-18

Si, max

1.0

6-8

Cu, max

0.35

Fe, m8x

06010

0.Ob0 -08

W, m a x

0.50 0.015

Ti + A l , max

0.50

0.02

co, max

0.20

Physical Properties: Density, lb/in.3

0.317

Melting point, OF

2470-2555

Thermal conductivity, Btu/hr-ft2(F/ft) at l3OO'F

12.7

Modulus of elasticity at -1300°F, psi

24.8 x 106

Specific heat, Btu/lb-"F at l3OO'F

0.138

Mean coefficient of thermal expansion, 70-1300'F range, in./in.-'F

8.0 x io6

Mechanical Properties: a Maximum allowable stress, psi:

at lOOO'F 1100°F

17,ooo

L200"F 1300'~

6,ooo

a ASME Boiler and Pressure Vessel Code Case 1315.

13,000

3,500

21 A flow of 200 f t 3/day (STP) i s passed continuously through t h e

systems.

f u e l pump bowl t o transport the f i s s i o n product gases t o activated charcoal adsorber beds.

The radioactive xenon i s retained on t h e charcoal f o r a

minimum of 90 days, and t h e krypton f o r 7-l/Z' days, which i s s u f f i c i e n t f o r all but t h e 85Kr t o decay t o i n s i g n i f i c a n t l e v e l s . The 85Kr i s maintained well within tolerance, t h e e f f l u e n t gas being d i l u t e d w i t h 21,000 cfm of a i r , f i l t e r e d , monitored, and dispersed from a 3-ft-dim by 100-ft steel-cont ainment v e n t i l a t i o n stack. The cover-gas system i s a l s o used t o pressurize t h e drain tanks t o move molten s a l t s i n t o t h e f u e l and coolant c i r c u l a t i n g systems.

Gas

from these operations i s passed through charcoal beds and f i l t e r s before

it i s discharged through t h e off-gas stack. L

2.4.11

Instrumentation and Control Systems

Nuclear and process control are both important t o t h e operation of t h e MSRE.

The reactor has a negative temperature coefficient of 6.4 t o

9.9 x

(Ak/k)/OF,

depending on t h e type of f u e l t h a t i s being used.

The excess r e a c t i v i t y requirements are l i s t e d i n Table 2.3,

and they

a r e not expected t o exceed 4 x lom2Ak/k at the normal operating temperature.

The t h r e e control rods have a combined worth of 5.6 t o 7.6 % Ak/k,

depending upon the f u e l composition.

Their major functions a r e t o elimi-

nate t h e w i d e temperature v a r i a t i o n s t h a t would otherwise accompany changes i n power and xenon poison l e v e l and t o make it possible t o hold t h e r e a c t o r s u b c r i t i c a l t o a temperature 200 t o 300°F below t h e normal

operating temperature.

They have some s a f e t y functions, most of which

a r e concerned with t h e s t a r t u p of t h e reactor.

Rapid action i s not re-

quired of t h e control rods; however, a magnetic clutch i s provided i n t h e drive t r a i n t o permit t h e rods t o drop i n t o t h e thimbles w i t h an acc e l e r a t i o n of 0.5 g as a convenient way of providing i n s e r t i o n r a t e s t h a t are more rapid than t h e removal r a t e s .

Burnup and growth of long-

l i v e d f i s s i o n product poisons i s compensated by adding f u e l through t h e sampler enricher.

Complete shutdown of t h e reactor i s accomplished by

draining t h e fuel. When t h e reactor i s operated a t power l e v e l s above a few hundred kilowatts, t h e power i s controlled by regulating t h e a i r flow, and

Table 2.3.

Reactivity Requirements

Reactivity, % &/k Loss of delayed neutrons by c i r c u l a t i n g f i e 1

-0. 3

Entrained gas

-0.2

Power coefficient (from r i s e i n graphite temperature)

-0.1

Xenon poisoning (steady s t a t e at 10MW)

-0.7

S amarium-149 t r a n s i e n t

-0.1

Burnup (120 g of f'uel)

-0.1

Margin f o r operation of control rods

4.4

-1.9

Total Uncertainty i n estimates (primarily xenon) Total

(+)-LO

t o (-)-0.4

-2.9 t o -1.5

thereby t h e r a t e of heat removal, at t h e radiator.

The power l e v e l i s

determined by measuring t h e flow r a t e and temperature difference i n t h e coolant s a l t system.

The control rods operate t o hold t h e f u e l o u t l e t

temperature from t h e reactor constant, and t h e i n l e t temperature i s perA t low power t h e control rods operate

mitted t o vary with power level.

t o hold t h e neutron flux constant, and t h e heat w i t h d r a w a l a t t h e radia t o r o r t h e input t o t h e heaters on piping and equipment i s adjusted t o keep t h e temperature within a specified range. Preventing t h e salts from freezing, except at freeze flanges and valves, and protecting t h e equipment from overheating, a r e among t h e most important control functions.

Over one thousand thermocouples a r e

i n s t a l l e d throughout t h e f u e l and coolant s a l t systems, and about threefourths of these serve indication, a l a r m , or control functions.

The

heating and cooling equipment i s controlled t o maintain temperatures (throughout t h e systems) within specified ranges. D i g i t a l computer and data handling equipment a r e included i n t h e instrumentation t o provide r a p i d compilation and analysis of t h e process data.

This equipment has no control function but gives current infor-

mation about a l l important variables and warns of abnormal conditions.

2.5

Fuel Processing

Batches of f u e l or f l u s h salt which have been removed from t h e r e a c t o r c i r c u l a t i n g system can be processed i n separate equipment t o per-

m i t t h e i r reuse o r t o recover t h e uranium. S a l t s t h a t have been contaminated with oxygen t o t h e s a t u r a t i o n point (about 80 ppm of %), and t h u s tend t o p r e c i p i t a t e t h e f u e l constituents

as oxides, can be t r e a t e d with a hydrogen-hydrogen f l u o r i d e gas mixture t o remove t h e oxygen as water vapor.

These salts can then be reused.

A salt batch unacceptably contaminated w i t h f i s s i o n products, or one i n which it i s desirable t o d r a s t i c a l l y change t h e uranium content, can be t r e a t e d w i t h f l u o r i n e gas t o separate t h e uranium fram t h e c a r r i e r

salt by v o l a t i l i z a t i o n of UF6.

I n some instances t h e c a r r i e r salt w i l l

be discarded; i n others uranium of a d i f f e r e n t enrichment, thorium, o r other constituents w i l l be added t o give t h e desired composition.

hi?J L

The processing system c o n s i s t s of a salt storage and processing tank, supply tanks f o r t h e H2, HF, and F t r e a t i n g gases, a high temper2

a t u r e (750OF) sodium f l u o r i d e adsorber f o r decontaminating t h e UF6’ several low-temperature portable adsorbers f o r Ul? a caustic scrubber,

6’

and associated piping and instrumentation.

A l l except t h e UF6 adsorbers

a r e located i n t h e f’ue1,processing c e l l below t h e operating f l o o r o f Bldg. 7503, as shown i n Fig. 4.4 After t h e uranium has been t r a n s f e r r e d t o t h e UF6 adsorbers, they a r e transported t o t h e ORNL V o l a t i l i t y P i l o t Plant a t X-10, where t h e

6 is t r a n s f e r r e d t o product cylinders f o r r e t u r n t o the‘&C. , pToduction

plants.

2.6 Plant Arrangement The general arrangement of Building 7503 i s shown i n Fig. 4 . 3 . main entrance i s a t t h e north end.

The

Reactor equipment and major a u x i l -

i a r y f a c i l i t i e s occupy t h e west half of t h e building i n t h e high-bay area.

The e a s t half of t h e building contains t h e c o n t r o l room, o f f i c e s ,

change rooms, instrument and general maintenance shops, and storage areas.

Additional o f f i c e s a r e provided i n a separate building t o t h e

e a s t of t h e main building. Equipment f o r v e n t i l a t i n g t h e operating and experimental areas i s located south of t h e main building.

A small cooling tower and small

buildings t o house s t o r e s and t h e d i e s e l - e l e c t r i c emergency power equipment a r e located west of t h e main building. The r e a c t o r primary system and t h e d r a i n tank system are i n s t a l l e d i n shielded, pressure-tight r e a c t o r and d r a i n tank c e l l s , which occupy most of t h e south half of t h e high-bay a r e a .

These c e l l s a r e connected

by an open 3-ft-diam duct and a r e thus both constructed t o withstand t h e same design pressure of 40 psig, with a leakage r a t e of less than 1 vol % per day.

A vapor-condensing system, buried i n the ground south

of t h e building, i s provided t o keep t h e pressure below 40 psig‘during t h e maximum c r e d i b l e accident by condensing t h e steam i n vapors t h a t a r e discharged from t h e r e a c t o r c e l l .

When t h e r e a c t o r i s operating,

t h e r e a c t o r and d r a i n tank c e l l s are sealed, purged w i t h nitrogen t o

obtain an a t d p h e r e that i s l e s s than 5% oxygen, and maintained a t about 2 p s i below atmospheric pressure. The r e a c t o r c e l l i s a carbon s t e e l containment v e s s e l 24 f% in d i ameter alzd 33 f t i n o v e r a l l height.

The t o p i s f l a t and c o n s i s t s of two

l a y e r s of removable concrete plugs and beams, f o r a t o t a l thickness of

7 ft. A t h i n stainless s t e e l membrane i s i n s t a l l e d between t h e two l a y e r s o f plugs and welded t o t h e w a l l of t h e s t e e l v e s s e l t o provide a t i g h t s e a l during operat ion. The r e a c t o r c e l l v e s s e l i s located within a 30-ft-diam s t e e l tank. The annular space i s f i l l e d with a magnetite sand and water mixture,

and t h e r e i s ‘a minimum of 2 f t of concrete shielding around t h e outer

I n addition t o t h i s shielding t h e r e a c t o r v e s s e l i s surrounded by a 14-in.-thick steel-and-water thermal s h i e l d . tank.

The drain tank c e l l adjoins t h e r e a c t o r c e l l on t h e north.

It i s

a 17-1/2-f% by 21-1/2-ft by 29-ft-high rectangular tank made of r e i n forced concrete and l i n e d w i t h s t a i n l e s s s t e e l . The roof s t r u c t u r e , i n cluding t h e membrane, i s s i m i l a r t o that o f t h e r e a c t o r c e l l . The coolant c e l l abuts t h e r e a c t o r c e l l on t h e south.

It i s a

shielded area with controlled v e n t i l a t i o n but i s not sealed. The blowers t h a t supply cooling a i r t o t h e r a d i a t o r are i n s t a l l e d i n an e x i s t i n g blower house along t h e west w a l l of t h e coolant c e l l .

Rooms containing a u x i l i a r y and s e r v i c e equipment, instrument t r a n s mitters, and e l e c t r i c a l equipment a r e located along t h e east wall of t h e reactor, d r a i n tank and coolant c e l l s ,

Ventilation of t h e s e rooms is

controlled, and some are provided w i t h shielding. The north half of t h e building contains s e v e r a l small shielded c e l l s i n which t h e v e n t i l a t i o n i s controlled, but which a r e not g a s - t i g h t . These c e l l s are used for s t o r i n g and processing t h e f u e l , handling and s t o r i n g l l q u i d wastes, and s t o r i n g and decontaminating r e a c t o r equip-

ment. The high-bay a r e a of t h e building over t h e c e l l s mentioned above i s l i n e d with metal, has a l l b u t t h e smaller openings sealed, and i s provided with a i r locks.

-W w

Ventilation i s controlled and t h e area i s normally

operated a t s l i g h t l y below atmospheric pressure.

The e f f l u e n t a i r from

26 t h i s area and from a l l other controlled-ventilation areas i s f i l t e r e d , and monitored before it i s discharged t o t h e atmosphere.

The contain-

ment v e n t i l a t i o n equipment consists of a f i l t e r p i t , two fans, and a 100-ft-high f i e 1 stack.

They a r e located south of t h e main building

and a r e connected t o it by a v e n t i l a t i o n duct t o t h e bottom of t h e r e a c t o r c e l l and another along t h e east s i d e of t h e high bay. The vent house and charcoal beds f o r handling t h e gaseous f i s s i o n products from t h e r e a c t o r systems a r e near t h e southwest corner of t h e main building.

The carbon beds a r e i n s t a l l e d i n an e x i s t i n g p i t that

i s f i l l e d with water and covered with concrete slabs. and p i t are a l s o controlled-ventilation a r e a s .

The vent house

Gases fYom t h e carbon

beds a r e discharged i n t o t h e v e n t i l a t i o n system upstream of t h e f i l t e r .

Maintenance of equipment i n t h e fuel c i r c u l a t i n g and d r a i n tank systems w i l l be by removal of one o r more of t h e concrete roof plugs and use of remote handling and viewing equipment.

A heavily shielded

maintenance c o n t r o l room w i t h viewing windows i s located above t h e operating f l o o r f o r operation of t h e cranes and other remotely cont r o l l e d equipment.

This room w i l l be used primarily when a l a r g e num-

ber of t h e roof plugs a r e removed and a piece of highly radioactive equipment i s t o be t r a n s f e r r e d t o a storage c e l l . EQuipment i n t h e coolant c e l l cannot be approached when t h e rep a c t o r i s operating, but since t h e induced a c t i v i t y i n t h e coolant salts i s short l i v e d , t h e coolant c e l l can be entered f o r d i r e c t maintenance

s h o r t l y a f t e r r e a c t o r shutdown.

cc%i

SITE

The Molten-Salt Reactor Ekperiment is located i n Melton Valley about one-half mile southeast of t h e main X-10 area of t h e Oak Ridge National Laboratory, Oak Ridge, Tennessee.

The s i t e can be approached from e i t h e r

t h e northeast o r southwest on t h e asphalt-surfaced 7 9 0 Road.

A location

map i s shown i n Fig. 3.1. It may be noted t h a t i n t h e p l o t plan, Fig. 3.2, and on a l l con-

s t r u c t i o n drawings, t h a t t h e long a x i s of t h e building has been taken as c

t h e reference, o r p l a n t , north. this

The t r u e north l i e s about 30° e a s t of

.* The b r i e f d e s c r i p t i v e remarks made here regarding t h e MSRE s i t e a r e

s u f f i c i e n t only t o o u t l i n e some o f t h e f a c t o r s influencing design of t h e experiment.

The meteorology, climatology, geology, hydrology, seismology,

and t h e general s u i t a b i l i t y of t h e location from a s a f e t y standpoint a r e discussed i n d e t a i l i n t h e Safety Analysis Report, P a r t V, o f t h i s r e p o r t . m e location i s a s a f e one6,7,8 f o r construction of r e a c t o r equipment, a s

i s evidenced by t h e s e v e r a l other r e a c t o r s i n s t a l l e d i n t h e a r e a and t h e f a c t t h a t t h e ARE and t h e 60-Mw(thermal) ART experiments were approved f o r t h e same s i t e . The t e r r a i n consists of wooded h i l l s and v a l l e y s . t h e MSRE s i t e i s about 8 9 f't above sea l e v e l .

The elevation of

Haw Ridge, which l i e s

between t h e MSRF: and t h e main X-10 area, has an average elevation along t h e top of about 980 f't

. The Clinch River (Melton H i l l Reservoir) l i e s

two o r more miles t o t h e e a s t and south and marks t h e boundary of t h e

ORNL reservation.

The e i g h t or t e n square miles included i n t h i s bend

o f t h e r i v e r are a l s o occupied by s i x other ORNL r e a c t o r i n s t a l l a t i o n s . These are, i n most instances, separated from each other by intervening h i l l s and distances of one-half mile o r more.

The i n s t a l l a t i o n s include

t h e Tower Shielding F a c i l i t y , t h e Health Physics Research Reactor (HPRR),

*In most instances t h i s r e p o r t gives compass d i r e c t i o n s only t o ind i c a t e a general relationship, and t h e d i s t i n c t i o n between p l a n t north and t r u e north i s not important. I n general, unless otherwise s t a t e d , t h e d i r e c t i o n s given a r e r e f e r r e d t o p l a n t north. Should t h e reader have need f o r exact compass bearings, care should be taken t o i d e n t i f y t h e north used i n a p a r t i c u l a r reference o r drawing.

28 UNCLASSIFIED OR N L-LR- DWG 4406 R

F i g . 3.1.

ORNL Area Map.

MELTON VALLEY DRIVE

-18,900

48.800

UTILITY BUILDING

i f i

18 700

18.600

QOO

FIG. 3.2 P L O T PLAN OLTEN SALT REACTOR E X P E R I M E N T BUILDING 7503

!%LOO

t h e High-Flux Isotope Reactor (HFIR), and t h e associated Trans-Uranium F a c i l i t y (TRUF), t h e Experimental Gas-Cooled Reactor (EGCR), and t h e now dismantled Homogeneous Reactor Experiment (HRE-2, o r HRT)

The d i r e c t i o n of t h e prevailing wind i s from t h e southwest, but close t o t h e ground i n Melton Valley during t h e night, o r i n s t a b l e cond i t i o n s , t h e wind tends t o be from t h e northeast regardless of t h e d i r e c t i o n of t h e gradient wind.

Very strong winds a l o f t , however, do con-

t r o l t h e d i r e c t i o n and v e l o c i t y of t h e v a l l e y wind.

A frequently en-

countered condition i s f o r up-valley l i g h t a i r movement from t h e southwest during t h e day followed by a down-valley movement a t night. 9,10 The s o i l i s l a r g e l y Conasauga shale, and t h e r e a r e no p e r s i s t e n t

limestone beds i n t h e area t o cause rapid movement of underground water through solution channels o r caverns.

The shale i s r e l a t i v e l y imper-

meable t o water, and such ground flow as might e x i s t i s probably limited t o a few f e e t per week.

Surface water has a n a t u r a l drainage t o t h e

south i n t o a small spring-fed t r i b u t a r y of Melton Branch, which i n t u r n , empties i n t o Whiteoak Creek. 9 , l O Only one o r two very s l i g h t earthquakes occur per year i n t h e Tennessee Valley, and it has been judged highly improbable t h a t a major shock w i l l occur i n t h e Oak Ridge area f o r s e v e r a l thousand years. 9 , l O The MSRE i s supplied with potable water *om system.

t h e X-10 d i s t r i b u t i o n

The source of t h e water i s t h e Clinch River.

After treatment

t h e water i s stored i n a 7-million-gal r e s e r v o i r located near t h e Y - 1 2 Plant.

This supply serves t h e main laboratory complex and a l s o f’urnishes

water t o a 16-in. l i n e which makes a complete loop t o t h e south of X-10 t o supply t h e several r e a c t o r s i t e s , a s shown i n Fig. 3.3.*

Two 1.7-

million-gal tanks, with maximum water l e v e l of 1055 f t elevation, a r e located a t t h e top o f Haw Ridge as p a r t o f t h i s loop system.

The MSRE

normally receives water through a 12-in. main l a i d along 7 9 0 Road t o t h e e a s t of t h e MSRE r e a c t o r Building 7503 and joining t h e 16-in. loop where it crosses t h e road.

An e x i s t i n g 6-in. l i n e along t h e same road

t o t h e west o f Bldg. 7503 serves as an a l t e r n a t i v e supply l i n e . t o t a l a v a i l a b l e capacity probably exceeds 4000 gpm.

The

Building services

*See ORNL Dwg F-4692 for complete layout of t h e X-10 water supply system.

Unclassified ORNL-DWG 64-8806

c 4

E T H E L CHURCH

BUILDING 7500

HEALTH WYSICS RESEARCH REACTOR ACCESS R O L D

GI4 FLUX ISOTOPE REACTOR

,-*-.AEC-TVA

FENCE

Figure 3.3.

Y E L T O N VALLEV ACCESS R O A D

Potable Water Supply t o MSRE

32 and t h e f i r e protection system d r a w d i r e c t l y from t h e potable supply. Process w a t e r a l s o comes f'rom t h e same supply, but a backflow preventer i s i n s t a l l e d i n t h e process water l i n e t o p r o t e c t t h e potable water

system. The MSRE i s supplied with e l e c t r i c power f'romthe 19-kTVA system through a substation located j u s t north of t h e main X-10 area, a s shown

i n Fig. 3.4.

The 13.8-kv transmission l i n e from t h e substation t o t h e

MSRE ( O m Circuit 234) s k i r t s t h e western side of X-10 along F i r s t

Street.

A 13.8-kv feeder l i n e from another 1% t o 13.8-kv transformer

a t t h e same substation (ORNL Circuit 294) passes t o t h e e a s t of X-10 t o supply t h e HFIR a r e a .

This l i n e passes close t o t h e MSRE, and t h e

two c i r c u i t s are connected together through automatic t r a n s f e r switches on poles a t t h e MSRE s o t h a t each can serve as an a l t e r n a t i v e t o t h e other.

The MSRE i s normally supplied through C i r c u i t 234.

The l3.8-kv, 3-phase, @-cycle input t o t h e MSRE serves process equipment through a new lpo-kva, 13.8 kv t o 480 v, transformer located on t h e west s i d e of Bldg. 7503.

An e x i s t i n g bank of t h r e e 250-kva,

13.8 kv t o 480 v, transformers on t h e e a s t s i d e of t h e building supplies t h e building l i g h t i n g , a i r conditioning, and other general purpose loads. Diesel-driven generators serve as a n a d d i t i o n a l source of emergency power.

These were o r i g i n a l l y i n s t a l l e d f o r t h e ARE and t h e ART.

There

are two 1200-rpm engine-generator s e t s of 300-kw capacity and one s e t

with a generator name-plate r a t i n g of 1200-kw but having a continuous duty, limited by t h e s i z e of t h e d i e s e l engine, of 300 kw.

The t o t a l

emergency generating capacity f o r t h e MSRE i s thus 9 0 kw.

"hese u n i t s ,

together with t h e a i r compressors and compressed a i r tanks used f o r s t a r t i n g t h e l a r g e engine and t h e b a t t e r i e s f o r s t a r t i n g t h e two smaller units are housed i n a generator house j u s t w e s t o f Bldg. 7503.

Saturated steam a t about 250 p s i g i s supplied t o t h e MSRE through a 6-in. main fYom t h e X-10 power p l a n t as shown i n Fig. 3.5. condensate r e t u r n .

There i s no

The chief uses f o r t h e steam a r e building heat and

a f e w d i s t i l l a t i o n processes.

Sanitary disposal f a c i l i t i e s consist of a s e p t i c tank and a drainage f i e l d west of t h e building.

. c Unclassified ORNL-DWG 64-8807

IS.0 KV -

+ II ;I

234

‘.... I

‘9ql

Figure

3.4.

I I

ELectricsJ

Distribution

System to MSHB

J‘

Unclassified ORNL DWG 64-8808

Wwe

3.5.

Stem Supply to MSRE

PLANT

4.1 General General views of Bldg. 7503 a r e shown i n Figs. 4.1 and 4.2. Since some of t h e building spaces serve no functions which a r e c l e a r l y r e l a t e d t o t h e requirements of t h e MSRE, a t t e n t i o n i s again c a l l e d t o t h e f a c t that t h e 7503 Area w a s o r i g i n a l l y constructed f o r t h e ARE and l a t e r modified f o r t h e AH?. It was not occupied between cancellation of t h e AF€ll i n 1957 and t h e present usage.

Although some

accommodations i n t h e MSHE design were necessary t o f i t t h e experiment i n t o t h e e x i s t i n g s t r u c t u r e s , considerable savings i n time and expense were gained by t h e i r use. Office, control room, shop and washroom spaces could be used almost without change, and t h e heat r e j e c t i o n equipment, which included a x i a l blowers, ducting and stack, were a valuable a s s e t .

The e x i s t i n g con-

tainment vessel height was increased by about 8-1/2 f t , and t h e shielding w a l l s , roof plugs, c e l l w a l l penetrations, supports, and other s t r u c t u r a l f e a t u r e s were extensively modified.

Considerable excavation

w a s needed within t h e high bay t o make room f o r t h e drain tank c e l l . I n modifying t h e e x i s t i n g buildings f o r t h e MSRE, t h e areas were divided i n t o f i v e c l a s s i f i c a t i o n s (see Ref. 11 f o r d e t a i l e d description): Class I .

These areas have high r a d i a t i o n l e v e l s a t a l l times

once t h e r e a c t o r has operated a t power and highly radioactive f u e l or

wastes have been handled i n t h e equipment.

They include t h e r e a c t o r

c e l l , d r a i n tank c e l l , f u e l processing c e l l , l i q u i d waste c e l l , charcoal bed p i t , e t c .

The equipment i n these areas must withstand r e l a t i v e l y

high r a d i a t i o n l e v e l s and i n most cases must be maintained by remote maintenance methods.

Direct maintenance w i l l be possible i n t h e f u e l

processing and l i q u i d waste c e l l s , but t h e equipment must first be decontaminated. Class 11. Areas i n t h i s c l a s s i f i c a t i o n a r e not accessible when f u e l salt i s i n t h e primary c i r c u l a t i n g system but can be entered withi n a short time a f t e r t h e salt has been drained.

The coolant s a l t area,

which includes t h e r a d i a t o r , coolant pump, and coolant-salt d r a i n tank, a r e i n t h i s category.

The west tunnel and t h e unshielded areas of t h e

cr\

0 In

4 bo *a

. T

blower house a r e other examples.

Equipment i n these areas can be re-

paired by d i r e c t approach.

Class 111. These a r e areas t h a t are accessible during periods of low-power operation of t h e reactor, such as t h e s p e c i a l equipment room and south e l e c t r i c service area, but cannot be entered i f t h e power i s above 1 M w .

The equipment i n these areas can be inspected and repaired

without draining t h e r e a c t o r . Class IV.

These are areas that a r e accessible o r habitable a t a l l

times except under t h e conditions described i n Class V, below.

These

areas include o f f i c e spaces, control rooms, e t c .

Class V.

The maintenance control room w i l l be t h e only habitable

areas during maintenance operations when large, radioactive components a r e being removed from t h e r e a c t o r c e l l .

must be evacuated.

The rest of t h e E R E s i t e

This shielded room contains remote control u n i t s

f o r t h e cranes and TV cameras. 4.2

Offices

Offices f o r t h e operational personnel a r e located i n Bldg. 7503 (see Section 4.3).

Administrative and supporting personnel are located

i n Bldg. 7509, which adjoins Bldg. 7503 on t h e e a s t s i d e .

Bldg. 7509

i s a new one-story, 43-ft x 87-ft concrete-block building equipped w i t h c e n t r a l a i r conditioning.

The main entrance f o r v i s i t o r s t o t h e MSRE

i s a t t h e e a s t end of t h i s building.

4.3 Building Above grade, Building 7503 i s constructed of s t e e l framing and asbestos cement type of corrugated siding with a sheet metal i n t e r i o r finish.

Reinforced concrete i s used i n almost a l l cases below t h e

850-ft elevation. Floor plans a t t h e 852- and 840-ft l e v e l s a r e shown i n Figs. 4.3 and 4.4.

The general location of equipment i s a l s o shown i n Fig. 4.3.

An elevation view i s shown i n Fig. 4.5. The w e s t half of t h e building above t h e 852-ft elevation i s about 42 f t wide, 157 f t long, and 33 f t high.

This high, o r crane, bay a r e a

houses t h e r e a c t o r c e l l , d r a i n tank c e l l , coolant salt penthouse, and most of t h e a u x i l i a r y c e l l s (see Section 4.3.9).

bpf

UNCLASSIFIED ORNL-DWG 64-8726

BUILDING 7509

UNCLASSIFIED ORNL DWB. 65-4547

Fig. 4 . 4 .

Plan a t 8404%Elevation.

, h'

UNCLASSIFIED ORNL DWG 64-597

Fig. 4.5. Elevation Building 7503.

42 The e a s t e r n half of t h e building above t h e 852-ft elevation i s 38 f t wide, 157 f t long, and about 1 2 f t high.

Offices f o r operational

personnel a r e located along t h e e a s t w a l l of t h e north end.

The main

control room, a u x i l i a r y control room, and a room used f o r t h e logger, computer, and f o r t h e s h i f t supervisor on duty a r e located across t h e h a l l on t h e western s i d e .

observation gallery.

The l a r g e h a l l provides ample space f o r an

Windows behind t h e control panel enable t h e

operating personnel t o view t h e t o p of t h e r e a c t o r c e l l and other operating areas of the high bay. t h e center of t h e building.

The change rooms a r e located near

The southeastern corner i s used f o r an

instrument shop, instrument s t o r e s and o f f i c e s f o r instrument depart-

ment supervisory personnel. Most of t h e western half of t h e building a t t h e 840 l e v e l i s 4

occupied by t h e reactor c e l l , d r a i n tank c e l l , and a u x i l i a r y c e l l s . The emergency nitrogen-cylinder s t a t i o n i s located against t h e west w a l l i n t h e northwest corner of t h i s l e v e l .

Switch boxes used i n t h e

heater c i r c u i t s a r e located across t h e aisle between columns A and C (see F i g . 4.3).

Behind these switch boxes i s an 8-ft x 40-1/2-ft

with a f l o o r elevation of 831-1/2 f t .

pit

This p i t contains heater c i r c u i t

induction regulators with some heater transformers mounted above.

i s accessible from t h e 840-ft l e v e l by stairs located a t t h e e a s t end.

Additional induction regulators and r h e o s t a t s a r e located a t column l i n e C between columns 2 and 3. The heater control panels and thermocouple scanner panels a r e located along column l i n e C between columns 3 and 4. The b a t t e r i e s f o r t h e 48- and 250-volt DC emergency power supply a r e i n an 18-ft x 18-ft b a t t e r y room i n t h e northeast corner.

The motor

generators and control panels for t h e 48-v system a r e i n an area west of t h e b a t t e r y room.

The main valves and controls f o r t h e f i r e pro-

t e c t i o n s p r i n k l e r system a r e i n s t a l l e d along t h e north w a l l . A maintenance shop area i s provided between columns 2 and 4.

The

process water backflow preventer i s i n s t a l l e d on t h e east w a l l between columns 2 and 3. The area between column l i n e s 4 and 6 houses t h e main l i g h t i n g breakers, switch boxes and transformers, t h e intercom control panel,

6:- I

43 water h e a t e r and a i r conditioners f o r t h e main control room and t r a n s m i t t e r room, as well a s a lunch room and meeting room f o r maintenance personnel.

The t r a n s m i t t e r room located between column l i n e s

5 and 6 i s described i n Section 4.3.7. The service room, a 16-ft by 27-ft room, located a t t h e northeast corner of t h e 840-ft l e v e l , serves as a small chemistry laboratory and access t o t h e service tunnel (Section 4.3.6).

The instrument panels

f o r the f u e l and coolant lube o i l systems a r e located i n t h i s a r e a .

4.3.1

Reactor C e l l The r e a c t o r c e l l , shown i n Fig. 4.5, i s a c y l i n d r i c a l carbon steel

v e s s e l 24 f t i n diameter and 33 f t i n o v e r a l l height (extending from t h e

819 t o 852-ft elevation), with a hemispherical bottom and a f l a t top. The lower 24-1/2 f t (819 t o 843-1/2-ft i n 1956.

It was designed f o r 195 p s i g a t 565°F and was t e s t e d hydro-

s t a t i c a l l y a t 300 pig.’:! thick.

elevation) was b u i l t f o r t h e ARI

The hemispherical bottom i s 1 t o 1-1/4 i n .

The c y l i n d r i c a l portion i s 2 i n . t h i c k except f o r t h e s e c t i o n

that contains t h e l a r g e penetrations, where it i s 4 i n . t h i c k .

This vessel was modified f o r t h e MSRE i n 1962 by lenghtening t h e Several c y l i n d r i c a l s e c t i o n 8-1/2 f t (843-1/2 t o 852-ft elevation)

new penetrations were i n s t a l l e d , and a 12-in. s e c t i o n of 8-in. sched-80 pipe closed by a pipe cap was welded i n t o t h e bottom of t h e vessel t o form a sump.

The extension t o t h e vessel was 2 i n . t h i c k except f o r t h e

top seceion, which was made as a 7-1/4-in.

t h e t o p s h i e l d beams i n place.

by 14-in. flange f o r b o l t i n g

The flange and t o p s h i e l d s t r u c t u r e

were designed f o r 40 psig, measured a t t h e t o p of t h e c e l l .

Both t h e

o r i g i n a l v e s s e l and t h e extension were made of ASTM A201, Grade B, f i r e box q u a l i t y steel.

Material f o r t h e extension was purchased t o speci-

f i c a t i o n ASTM A300 t o obtain steel with good impact properties a t low temperature.

S t e e l f o r t h e o r i g i n a l vessel was purchased t o s p e c i f i -

c a t i o n ASTM A201.

All the welds on t h e r e a c t o r c e l l vessel were inspected by magn e t i c particle methods if they were i n carbon s t e e l , o r by l i q u i d penetrant methods if they were i n s t a i n l e s s s t e e l . penetration welds were radiographed.

All b u t t welds and

A f t e r a l l t h e welding w a s completed,

t h e v e s s e l w a s s t r e s s relieved by heating t o 1150 t o 1200V f o r 7-l/2 h r .

Calculated s t r e s s e s i n t h e vessel were well below those permitted by ASME Boiler and Pressure Vessel Code Case 1272N-3. (49) Allowable s t r e s s e s f o r ASTM A-201 Grade B s t e e l were taken as 16,500 p s i f o r general membrane s t r e s s e s , 24,750 f o r general membrane plus general bending plus l o c a l membrane s t r e s s e s , and 45,000 p s i f o r combined primary and secondary s t r e s s e s . (13) The t o p of t h e c e l l i s constructed of two lqyers of 3-1/2-fhthick, reinforced concrete blocks, with a s t a i n l e s s s t e e l membrane between, as shown i n Figure 4.6.

The t o p l a y e r i s ordinary concrete with a d e n s i t y

of 150 lb/ft3, and t h e bottom l a y e r i s magnetite concrete with a d e n s i t y of 220 l b / f t 3

. Blocks i n both l a y e r s run east and west. To a i d i n

remote maintenance, the bottom l a y e r i s divided i n t o t h r e e rows of blocks.

Blocks i n t h e outer rows a r e supported on one end by a l 3 - i n .

by 4-in.-channel

i r o n r i n g w e l d e d t o t h e i n s i d e of t h e c e l l w a l l .

The

c a v i t y i n t h e channel i s f i l l e d w i t h s t e e l shot t o provide shielding f o r t h e . c r a c k s betwken edges of t h e blocks and t h e c e l l w a l l . s t e e l p l a t e s t i f f e n e r s a r e i n s t a l l e d a t 9" i n t e r v a l s .

One-half-inch

The t o p of t h e

channel i s at t h e 848-1/2-ft elevation. Two beams provide t h e rest of t h e support f o r t h e bottom l a y e r of blocks.

These beams were b u i l t of 36-in. WF l5O-lb I-beams w i t h angle

i r o n and s t e e l p l a t e s t i f f e n e r s . c r e t e f o r shielding.

The c a v i t i e s were f i l l e d w i t h con-

The beams rest on a b u i l t - u p support plant

assembly, which i s welded t o t h e s i d e of t h e c e l l a t t h e 847-ft-7-in. Offsets 6-1/4-in.

elevation.

by 26 i n . are provided i n t h e ends of t h e

bottom blocks t o f i t over t h e support beams. i r o n assure proper alignment.

Guides formed by angle

Several of t h e bottom blocks have stepped

plugs f o r access t o selected parts of t h e c e l l f o r remote maintenance. These a r e described i n P a r t X. The s i d e s of t h e blocks a r e recessed 1/2 i n . f o r 14 i n , down from t h e top.

With blocks s e t s i d e by side and with a 1/2-in. gap between,

a 1-1/2-in.

s l o t i s formed a t t h e top.

One-inch-thick s t e e l p l a t e 12 i n .

high i s placed i n t h e s l o t s f o r shielding.

The 11-gage, ASTM-A240 304

s t a i n l e s s s t e e l membrane i s placed on t o p of t h e bottom l a y e r of blocks and i s seal-welded t o t h e s i d e s of t h e c e l l . over each access plug.

Cover p l a t e s a r e provided

These a r e bolted t o t h e membrane and a r e sealed c

-LJ

UNCLASSIFIED ORNL DWG. 64-598

-ourruni

!\CELL

uLn

WALL S E C T I ON

Fig. 4 . 6 .

X X"

ANNu LUs-'

Shield Block Arraagement at Top of Reactor Cell.

46 by neoprene O-rings.

A 1/8-in. l a y e r of masonite i s placed on t o p of

the membrane t o protect it from damage by t h e t o p l a y e r of blocks.

The t o p blocks a r e beams that reach from one s i d e of t h e c e l l t o the other.

The ends of these blocks a r e bolted t o t h e t o p r i n g of t h e

c e l l by use of f i f t y 2-1/2-in.

No.

4 NC-2 studs, 57-1/4 i n . long, made

from ASTM-A32O, Grade L7, b o l t i n g s t e e l . i

These studs pass through holes

that were formed by c a s t i n g 3-in. sched-40 pipes i n t h e ends of t h e blocks.

Cold-rolled s t e e l washers, 9 i n . by 9 i n . by 1 i n . thick, and

standard 2-1/2-in.

No.

4 NC-2 nuts a r e used on each stud.

A removable structural steel platform (elevation 823-1/2 f t a t top)

forms a f l o o r i n t h e reactor c e l l vessel and a base f o r supporting major pieces of equipment. The reactor c e l l vessel i s i n s t a l l e d i n another c y l i n d r i c a l s t e e l tank that i s referred t o here as t h e s h i e l d tank.

This tank i s 30 f t

i n diameter by 35-1/2 f t high (elevation 816-1/2 t o 852 f t ) .

The

f l a t bottom i s 3/4 i n . thick, and t h e c y l i n d r i c a l s e c t i o n i s 3/8 i n . thick.

The s h i e l d tank s i t s on a reinforced concrete foundation t h a t

i s 34-1/2 f t i n diameter by 2-1/2 f t t h i c k .

The r e a c t o r vessel c e l l

i s centered i n t h e s h i e l d tank and supported by a 15-ft-dim by 5-ft-

high c y l i n d r i c a l s k i r t made on 1-in.-thick steel plate reinforced by appropriate rings and s t i f f e n e r s .

The skirt i s joined t o t h e hemispheri-

c a l bottom of t h e reactor c e l l i n a manner t h a t provides f o r some f l e x i b i l i t y and d i f f e r e n t i a l expansion and i s anchored t o t h e concrete foundation with eighteen 2-in.-diam b o l t s . From elevation 816-1/2 t o 846 f t , the annulus between t h e s h i e l d tank and t h e reactor c e l l vessel and skirt i s f i l l e d with magnetite

sand and water f o r shxelding.

The water contains about 200 ppm of a

chromate-type r u s t inhiWtor, Nalco-360.

A b-in.-diam

overflow l i n e

t o the coolant c e l l controls t h e water l e v e l i n t h e annulus. The region beneath the reactor c e l l vessel i n s i d e the s k i r t cont a i n s o n l y water, and steam will be produced t h e r e i f a l a r g e quantity of salt i s s p i l l e d i n t o t h e bottom of t h e r e a c t o r c e l l . An 8-in.-diam vent pipe i s provided t o permit t h e steam t o escape a t low pressure. (14)

This pipe connects i n t o t h e skirt a t t h e junction with t h e r e a c t o r c e l l and extends t o elevation 846 f t where it passes through t h e wall of t h e s h i e l d tank and terminates as an open pipe i n t h e coolant c e l l .

ICJ

_ __

. .. . ..

.. . ... _.

.__ .

__ __

_._"

, .,

. ,. , ,

,...

., . .".". . . .

L I

c r e t e ring improves t h e shielding a t t h e operating f l o o r l e v e l and provides some s t i f f e n i n g f o r the top of the reactor c e l l vessel. The

MSRE !eactor Cell Penetration Ntrber

Former Nmiber

R-4

Reactor Leak Detector

R-3

Electrical

I11

R-2

Electrical

R-1

Thermocouples

Instrumentation

concrete r i n g i s supported off t h e w a l l of the shield tank, and the Identification

V I

Sampler Offgas (918,

VI1

Sampler (999)

VI11

s-1

reactor c e l l w a l l i s f r e e t o move through the r i n g and t o expand and contract r e l a t i v e t o t h e shield tank. Numerous penetrations a r e required through t h e w a l l s of t h e reactor c e l l and shield tank t o provide f o r process and service piping, e l e c t r i c a l and instrument leads, and f o r other accesses.

t o 36-in.-diam pipe sleeves welded i n t o the walls of t h e reactor c e l l and t h e shield tank.

s-3

FP (516, 519, 524, 60

XI1

s-4

Component Coolant Air

Since t h e reactor c e l l w i l l be near 1 5 0 9 when

the reactor i s operating, and t h e temperature of t h e shield tank may a t t i m e s be as low as 609, bellows were incorporated i n most; of t h e sleeves t o permit radial and axial movement of one tank r e l a t i v e t o the The bellows are covered other without- p 've--stress.

;

(590, 7033 704, 70 Fp Level ( 5 9 2 3 ' 593,

The penetrations a r e 4-

Neutron Instrument fi

Ix X

with partial sleeves t o prevent t h e sand from packing t i g h t l y around

them.

Several other l i n e s a r e i n s t a l l e d i n the penetrations d i r e c t l y

XI11

Coolant Salt t o HX ( 2

XTV

Water Lines (830, 831

Spare

XVI

Water Lines (844, 845

XVII

Water Lines (838, 846 Water Lines (840, 841 * Coolant Salt t o Radia

w i t h welded s e a l s a t one o r both ends, o r they are grouped i n plugs

which a r e f i l l e d with concrete and inserted i n the penetrations. The major openings a r e the 36-in.-diam neutron instrument tube and

drain tank interconnection and t h e 30-in.-diam duct f o r ventilating

XVIII XIX

the c e l l when maintenance i s i n progress.

Offgas (522)

XXI

Offgas (561)

lMII

CeU Exhaust Duct (93 Themcouple

R-7

The original tank contained

several other 8-in. -and 24-in. -diam penetrations, and they were e i t h e r removed o r closed and f i l l e d with shielding. The penetrations, t h e i r

xx XXIII

From elevation 846 t o 852 f t , the annulus between t h e reactor c e l l and shield tank i s f i l l e d w i t h a ring of magnetite concrete. The con-

s i z e s and functions are l i s t e d i n Table 4.1. 4.3.2

Drain Tank Cell The drain tank c e l l shown i n Fig. 4.3 i s 17 f t , 7 i n . by 21 f t ,

2-1/2 in., with t h e corners beveled a t 45" angles f o r 2-1/2 f t .

Drain Tank Cell I n t e r connection (103, 33 521, 561, 920)

The f l a t f l o o r i s a t t h e 814-ft elevation, and the s t a i n l e s s s t e e l membrane between t h e two layers of top blocks i s a t t h e 838-ft-6-in. elevation. i

The open p i t extends t o the 852-ft elevation.

The c e l l w a s designed f o r 40 psig and when completed i n 1962, it

was hydrostatically t e s t e d a t 48 psig (measured a t the elevation of t h e membrane at 838-1/2 f t ) .

e.,

- _,__

""_

.. "... . . ._.

-. . .

Table 4.1.

" . .

.".

.. ... "

I . -

Reactor C e l l Penetrations

MSRE ieactor Cell Penetration Nuniber

Former Ntmzber

Identification

t e Location actor Cell Arc ( N = Oo Ref.)

APProX i n the Elevation

(ft)

Access Area

Penetration Size, ID ( i n *1

Shieldii ~~

Reactor Leak Detectors

R-4 R-3

I11

R-2

Electrical

R-1

Thermocouples

Instrumentation

FP Level (592; 593, 596) FP (516, 519, 524, 606) Component Coolant Air (917)

836 834 836 834 836 847 847 836-9" 834-5" 844-6" 836-9" 829-10"

XIII

Coolant S a l t t o HX (200)

840-10"

XIV

Water Lines (830, 831)

Spare

Water Lines (844, 845)

XVII

Water Lines (838, 846)

XVIII

Water Lines (840,841)

839-9" 839-9" 839-9" 839-9" 839-9" 837 839-9" 839-9" 824-iot1

Electrical

V I

Sampler Offgas (918, 542)

VI1

Sampler (999)

VI11

s-1

Fl? (590, 703, 704, 706) Neutron I n s t m e n t Tube

M X XI

s-3

XI1

xrx

Coolant S a l t t o Radiator (201)

XK XXI

Offgas (522)

XXII

Cell m u s t Duct (930)

XXIII XXIV

Offgas (561)

R-7

Thermocouple Drain Tank Cell I n t e r connection (103, 333, 521, 561, 920)

836 825 -2"

I I

24 24 24 24 24 4 6 18

Magnetite grout

Water i n penetration

Coolant Cell

36 4 18 6 24 8 8

205

Coolant C e l l

S t e e l shot except f o r s

210

Coolant C e l l

S t e e l shot except f o r s

220

Coolant Cell

220

Coolant Cell

225

Coolant C e l l

230

Coolant C e l l

8 8 24 6 6

245

CM! Cell

S t e e l p l a t e i n reactor 1

325

West Tunnel

Magnetite grout

330

Drain Tank C e l l

None needed

S. Elec. Serv. Area

45 60

S. Elec. Sew. Area S. Elec. S e n . Area S. Elec. Sew. Area

S. Elec. Serv. Area

110

High B a y

115 3-25 145 155 160

Hi€# B Y

165 170

SER

Coolant C e l l

185

Coolant C e l l

200

Service Tunnel High Bay SER SER

Magnetite grout Magnetite grout Magnet ite'grout Magnetite grout Fuel Sampler Steel plates Sand and water from ami

Tube f i l l e d with magnet:

Tube f i l l e d with sand 81 Lead i n annulus

S t e e l except f o r pipe ai

S t e e l shot except f o r s 1

S t e e l shot except f o r s

S t e e l shot except f o r s S t e e l except f o r pipe ai S t e e l shot except for s S t e e l shot except for s

Reference D r a w i n g s 3

lus

te grout d water f r o m annulus d heaters

raight-through pipes raight-through pipes raight -through pipes

might-through pipes raight-through pipes

d heaters raight -through pipes might-through p i p s

ell

(General References : EGGD-40704, 41487, 41489, 414%)

The bottom and s i d e s have a 3/16-in.-thick

stainless s t e e l l i n e r

backed up by heavily reinforced concrete, magnetite concrete being used where required f o r b i o l o g i c a l shielding.

The l i n e r i s welded t o an

angle-iron g r i d work a t approximately 8-in. spacing, with 1/2-in. plug welds.

The angle i r o n s a r e welded t o reinforcement rods embedded i n

t h e concrete. Vertical columns i n t h e north and south w a l l s a r e welded t o horizontal beams embedded i n t h e concrete of t h e c e l l f l o o r .

The tops

of t h e columns a r e welded t o horizontal 36-in. WF 160 I-beams a t elevation 842 f t 1 i n . t o 842 f t 4-3/8 i n . by welding a 1-1/4-in. p l a t e t o t h e web of t h e beam.

Eighty-two 3-1/4-in. by 4-1/2-in.

10-in. s t e e l keys a r e wedged i n t o t h i s s l o t t o hold down t h e t o p blocks. The t o p of t h e c e l l i s constructed using two l a y e r s of reinforced concrete blocks with an 11-gauge (A-204, 304 s t a i n l e s s s t e e l ) membrane between.

Both l a y e r s of blocks a r e ordinary concrete (density 150

lb/ft3).

The bottom l a y e r i s 4 f t t h i c k and t h e t o p l a y e r i s 3-1/2 f t

thick. The block arrangement shown i n Fig. 4.7 w a s selected t o f a c i l i t a t e remote maintenance.

One s i d e of t h e lower blocks, which run e a s t and

west, i s supported by a ledge a t an elevation of 834-1/2 f t .

The

other s i d e of these and t h e ends of t h e north-south blocks are supported by beams that extend from the e a s t t o t h e west side of t h e c e l l . These beams a r e b u i l t up of 24-in., lo5 .g-lb I-beams w i t h angle i r o n and steel p l a t e stiffeners. ‘The c a v i t i e s are poured f u l l of concrete f o r shielding.

These rest on a b u i l t - u p support p l a t e assembly, which

i s welded t o the s i d e of t h e s t a i n l e s s s t e e l l i n e r and i s anchored i n t o t h e concrete w a l l s .

Offsets, 4-1/4 i n . by 25-l/2 in., a r e pro-

vided i n t h e ends of the bottom blocks t o f i t over t h e support beams. 1f

V 11 grooves formed by angle i r o n s assure proper alignment.

The s i d e s

of t h e bottom blocks a r e recessed 1/2 i n . f o r 14 i n . down from t h e top. With two blocks side by side, with a 1/2-in. gap between t h e s i d e s

a t t h e bottom, a 1-1/2-in.

s l o t is formed a t t h e top.

One-inch s t e e l

p l a t e s , 12-in, high a r e put i n t o the s l o t s t o provide biological shielding.

Unclassified ORNL-DWG 64-881

“X r

9’

SECTION “XX” Fig. 4.7. Block Arrangement on Top of Drain Tank Cell.

.-.

..._...."".. .,.

., ,

,__._

i .

., , .. ,

.. .

The 11-gauge (ASTM A-240, 304 s t a i n l e s s s t e e l ) s e a l pan i s placed on t o p of the bottom blocks (elevation 838 f t 6 i n . ) , and i s sealwelded t o t h e sides of t h e c e l l .

A 1/8-in. layer of Masonite i s placed

on t o p of the s e a l pan t o protect it from damage during i n s t a l l a t i o n

of t h e t o p blocks.

The t o p blocks a r e beams that reach from t h e north

t o the south s i d e of t h e c e l l . 3-1/4-in.

by 4-1/2-in.

They are held down by t h e eighty-two

by 10-in. s t e e l keys discussed previously.

These a r e inserted i n t o s l o t s i n the top beams of t h e north and south s i d e s of the c e l l and a r e driven i n approximately 4 i n . , leaving approximately c,

5 i n . bearing on-the ends of the blocks. There a r e approximately four keys f o r each end of each block. A 1-1/2-in., 6 NC square nut i s welded t o t h e t o p of each key t o a i d i n removing t h e keys f o r handling. The f l o o r elevation i s 814 f t a t t h e highest point along the west w a l l and slopes 1/8 i n . / f t t o a trench along t h e e a s t wall. The trench slopes 1/8 i n . / f t toward the south and terminates i n a sump located i n t h e southeast corner.

The sump consists of a 10-in.-long section of

b i n . sched-40 pipe and a b i n . butt-welded cap (347 s t a i n l e s s s t e e l ) . Numerous l i n e s a r e required through t h e walls of t h e drain tank c e l l t o 'provide f o r process and service piping, e l e c t r i c a l and i n s t r u ment leads, and f o r other accesses. These enter through 3/4- t o 6-in. pipe o r pipe sleeve penetrations t h a t a r e welded t o the s t a i n l e s s s t e e l l i n e r and c a s t i n t o t h e concrete walls.

Lines a r e i n s t a l l e d

i n these individually o r grouped i n plugs that a r e f i l l e d w i t h conc r e t e and inserted.

The penetrations, t h e i r sizes, and functions a r e

given i n Table 4.2. 4 . 3 . 3 Coolant Cell and Coolant Drain Tank Cell Expect f o r l i n e 200 and 201 i n the reactor c e l l , a l l coolant s a l t piping i s located i n t h e coolant and coolant drain tank c e l l , shown i n Fig. 4.3. The t o p section of the coolant c e l l i s a concrete enclosure (penthouse) which r i s e s from the southwest corner of the high bay t o an elevation of 863 f t 3 i n .

The walls a r e ordinary reinforced, 24-in.-

t h i c k concrete except f o r t h e south corner, which i s l5-l/2 i n . t h i c k . Additional shielding f o r t h i s corner i s provided by the 2-ft-thick base f o r t h e stack, which goes t o the 859-ft elevation. A b i n . ledge a t elevation 861 f t 9 i n . on the southeast and northeast sides of the

Table 4.2.

Drain Tank Cell Penetrations

MSRE Drain

Xknk Cell Penetration Number 1 2

3 4

Identification Steam (804) Steam (805) Condensate (806) Condensate (807) Water (837) Water (836)

Location in Draw Tank Cell

Access Area

south wall

buth m c .

Penetration Size, I. D.

DKKDJcog48,

mD-55425

n n

iam. +a

na~n-40948,DKKB-41253

m-40948

8 9

13 14 15 l6 17 18

faste Cell

West Wall n

20 21 22

North Wall

23 24 -- 25 -26 27

m-40948, ~ ~ ~ - 4 1 2 8mu3-41281 0,

w. of Blag. n

Proc. Cell

__ n - -

B-1 to 36

c-i to 36 D-1 t o 36 E-1 to 36 A-37 to 60 B-37 to 60 c.-37 to 60

D-37 to 60 E-37 to 60 F-37 to 60

East wall Instrumentation Thermocouples Thermocouples Themcouples Electrical Electrical Electrical Electrical Electrical Electrical

mc. em. Age6 I.

spare

spare Cover Oas (572, 574, 576)

Spare

K L

spare spare

Component Coolant Air

East Wall

Component Coolant Air

(9U, 912, 913)

Elec. em. Area

(920) P

DP Cell (UI 806 and 807)

Leak Detector

Elec. em. Area n

Dm-9

DKKD-40948, DKKB-41280

a---n--

A-1 to 36

References (Oeneral References: EXD-40708 W W , 40882, 415329 41513;

53 penthouse supports t h e bottom l a y e r of t h e t o p s h i e l d blocks.

These

a r e constructed of 12-in.-thick reinforced regular concrete.

The 12-

i n . - t h i c k t o p shielding blocks rest on t h e bottom blocks.

The 1/2-in.

gaps between plugs i n each l a y e r a r e staggered f o r b e t t e r shielding. Ledges a t t h e 862-ft-+in. 861-ft-9-in.

elevation on t h e northeast side and a t t h e

elevation on t h e other s i d e s a r e provided f o r shielding.

The bottom of t h e coolant r a d i a t o r i s a t elevation 836 f t 1-3/4 i n . The f l o o r of t h e coolant s t a c k enclosure, located south of t h e r a d i a t o r ,

i s a t elevation 835 f t 5 i n . , and t h e 2 - f t - t h i c k reinforced regular concrete walls extend t o t h e 859-ft elevation. A 1-1/4-in.

s t e e l g r a t i n g and/or ll-gauge sheet metal pan a t

elevation 834 f t 11 i n . separates t h e coolant c e l l from t h e coolant d r a i n tank c e l l .

Thus, t h e coolant d r a i n tank c e l l i s below ground

l e v e l on a l l s i d e s .

The elevation of t h e concrete f l o o r i s 820 f t .

It i s bounded by t h e r e a c t o r c e l l annulus on t h e northeast and by t h e s p e c i a l equipment room on t h e e a s t . Penetrations No. X I I I t o XXII from t h e r e a c t o r c e l l terminate i n t h e coolant c e l l o r coolant d r a i n tank c e l l .

The w a l l between t h e

coolant and coolant d r a i n tank c e l l s and t h e s p e c i a l equipment room i s 16-in. t h i c k t o t h e 835-ft-5-in.

elevation and 12 i n . t h i c k above t h i s .

Existing openings between t h e c e l l s (2 f t by 2 fti; 3 f t by 4 f t 6 i n . ;

9 f t by 5 f t 5 in.;

and 5 f t by 3 f t ) a r e closed by stacked magnetite

concrete blocks t o enable proper v e n t i l a t i o n of both areas and t o

provide adequpte shielding.

A 6-ftdwide concrete ramp with 2 - f t stairs

i n t h e center (slope 7 i n 12) extends from t h e northwest corner of t h e coolant d r a i n tank c e l l (west northwest t o t h e blower house a t t h e

840-ft elevation.

This i s closed o f f by stacked magnetite blocks.

Shielding from t h e coolant pump and piping i s provided by 8 f t of barytes blocks stacked above t h e 835-ft elevation between t h e radia t o r housing and r e a c t o r shield.

4.3.4

Special Equipment Room The major items of equipment located i n t h e s p e c i a l equipment room

a r e t h e component coolant blowers, t h e containment boxes f o r the f u e l pump, cover gas and babbler l i n e s , t h e W-in.-diam c e l l v e n t i l a t i o n l i n e and t h e rupture d i s c s and l i n e s t o t h e vapor-condensing system.

This c e l l i s

54 located southeast of t h e r e a c t o r c e l l and, as discussed previously, has a comon w a l l with coolant c e l l and coolant drain tank c e l l .

The other

w a l l s are 12-in.-thick reinforced concrete below ground l e v e l .

The

c e l l i s 1 5 f t 11 i n . by 17 f t .

The f l o o r elevation i s 828 f t 7 i n .

except f o r a 5-ft by 1 5 - f t - l l - i n . by 3-ft-deep p i t which runs e a s t and west 2 f t 3 i n . f r o m t h e south w a l l . The t o p c o n s i s t s of 2 rows of removable concrete s h i e l d plugs Each row of blocks i s one f o o t t h i c k .

w i t h staggered j o i n t s .

The

bottom row i s supported by a b i n . ledge a t t h e 850-ft elevation. Containment i s provided by v e n t i l a t i o n from the s t a c k fans. Penetrations No. X, XI, and XI1 from t h e reactor c e l l terminate i n t h e s p e c i a l equipment room.

A t y p i c a l e l e c t r i c a l lead penetration

i s shown i n Fig. 19.10.

4.3.5

,Pump Room

The p i t pump and sump pumps a r e located i n t h e pump room. room

This

i s located under t h e north end of t h e s p e c i a l equipment room.

It i s 7-l/2 f t by 1 5 f t 3 i n . by 6 f t 7 i n . high, w i t h a f l o o r

elevation of 820 f t .

A 3-ft by 3-ft sump located near center of

t h e north w a l l extends t o t h e 811-ft elevation.

Access t o t h e pump

room i s through a 3-ft by 4 - f t hatch located near column C-8.

4.3.6

Service Tunnel The f u e l and coolant lube o i l systems and t h e r e a c t o r c e l l v e n t i l a -

t i o n block valves (HCV 930 A and B) a r e located i n t h e service tunnel. This tunnel i s 7 f t wide by 11 f t high by approximately 67 f t long.

It i s located under t h e southeast corner of t h e 7503 building and

extends south and west outside t h e building.

833 f t 3 i n .

The f l o o r elevation i s

Normal access i s from t h e service room on t h e 840-ft

level;. however, a 3 - f t by 3 - f t hatch located near t h e west end provides access from outside t h e building.

This hatch i s normally closed by

a sheet-metal-covered wood l i d .

Containment i s by v e n t i l a t i o n from t h e

stgck fans. Penetration V I 1 1 from t h e reactor c e l l terminates in t h e service tunnel.

4.3.7 Transmitter Room and E l e c t r i c Service Areas The area north and west of t h e reactor c e l l annulus a t elevation

831 f t (west tunnel) connects by a narrow passage t o a similar a r e a north and e a s t of t h e reactor c e l l annulus ( e a s t tunnel).

These extend

eastward under t h e 840-ft f l o o r t o a 24-in.-thick concrete w a l l 12 f t north of column l i n e 6. service area.

This e n t i r e area i s c a l l e d t h e south e l e c t r i c

S i x penetrations (No. I, 11, 111, IV, V, and XXIII)

frim t h e r e a c t o r c e l l and eighteen (No. Q and R and 1 t o 16) from t h e d r a i n tank c e l l terminate i n t h i s a r e a .

The walls, except f o r those

joining t h e r e a c t o r o r drain tank c e l l s , a r e located below ground level.

The c e i l i n g , which connects w i t h the t r a n s m i t t e r room, i s 24-

i n . -thhck reinforced concrete w i t h a 3-ft-7-1/2-in.

by 6-ft-7-1/2

i n . by

24-in.-thick concrete plug f o r access t o t h e a r e a .

This plug has a

b i n . by 12-in. o f f s e t on a l l s i d e s f o r shielding. The north e l e c t r i c service area i s located north of t h e 24-in.-

t h i c k concrete w a l l mentioned above. 824-ft elevation.

Most of t h e remaining drain tank c e l l penetrations

terminate i n t h i s area (see Table 4.2) cell.

The f l o o r of t h i s room i s a t t h e

as well as some from the spare

The c e i l i n g of t h i s a r e a and t h e f l o o r of t h e t r a n s m i t t e r room

above i s 2- t o &-in.-thick reinforced concrete poured on "Q" decking

No. 3-16.

Containment i s by v e n t i l a t i o n from t h e s t a c k fans.

A 2-ft

by 3-ft manhole with hinged s t e e l door provides access from t h e t r a n s m i t t e r room.

The f l o o r of t h e t r a n s m i t t e r room i s ,at t h e 840-ft elevation. The 5-in. f l o o r of t h e high-bay, 852-ft elevation i s t h e c e i l i n g of t h e t r a n s m i t t e r room.

A 5-ft by 9-ft-3-1/2-ine

plug can be removed from

t h e high-bay f l o o r s o that t h e high-bay crane can be used t o remove

t h e shielding plug on t h e 840-ft l e v e l between t h e t r a n s m i t t e r room and t h e south e l e c t r i c service a r e a .

This room i s approximately 16 f t

by 20 f t and contains t h e l e a k d e t e c t o r system and instrumentation f o r t h e d r a i n tank weigh c e l l s , pump l e v e l and speed, sump l e v e l , component

cooling air, e t c .

4.3.8

A a d l i a r y Cells S i x smaller c e l l s a r e located between columns 2-5 and A-C.

Removable

concrete blocks provide access from t h e high bay area a t t h e 852-ft e l e -

vation.

General information regarding these c e l l s a r e given i n Table 4.3.

Containment of each i s by v e n t i l a t i o n from t h e s t a c k fans.

kid *

Descriptions

of t h e i r projected uses a r e given below. Fuel Processing C e l l .

The f u e l storage tank and other i n c e l l equip-

ment f o r hydrofluorinating o r f l u o r i n a t i n g t h e f u e l o r f l u s h salt a r e located i n t h i s c e l l .

The absorber cubicle i s located e a s t of t h i s c e l l

at t h e 852-ft l e v e l . Decontamination Cell. Both

T h i s c e l l contains a decontamination tank.

tank and c e l l a r e used f o r underwater maintenance and storage of

contaminated equipment. Liquid Waste C e l l .

The l i q u i d waste tank, sand f i l t e r , and c e l l

sump j e t block valves a r e located i n t h i s c e l l . Remote Maintenance C e l l .

The l i q u i d waste pump and waste tank

exhaust blower a r e located i n t h i s c e l l .

It w i l l a l s o be used as a

remote maintenance p r a c t i c e c e l l . Hot Storage C e l l .

This c e l l w i l l be used t o s t o r e contaminated

e q u i p e n t removed from t h e reactor or d r a i n tank c e l l . Spare C e l l .

The absolute f i l t e r i n t h e chemical processing c e l l

a i r exhaust l i n e and t h e flame a r r e s t e r i n t h e chemical processing o f f gas l i n e i s located i n t h i s c e l l .

4.3.9

High-Bay Containment Enclosure The high-bay containment enclosure between columns 2-8 and A-C i s

42 f t by 136 f t w i t h a c e i l i n g elevation of 885 f t 4 i n .

The containment

extends e a s t near column 8 t o include t h e neutron instrument tube and provide room f o r t h e f u e l salt sampler.

A f a l s e c e i l i n g and containment s e a l i s i n s t a l l e d 1 5 ft above t h e

f l o o r between columns 8-9 and B-C.

The containment walls extend from

t h i s elevation t o 885 f t 4 i n . along column l i n e C from columns 8 t o 9, then west along calumn l i n e 9 t o column A, then north along column A t o column 8.

Thus t h e coolant c e l l penthouse i s included i n t h e high

bay a r e a and t h e high-bay crane can be used f o r handling equipment and shielding blocks i n t h i s c e l l .

A 1 0 - f t by 1 2 - f t loading hatch and Bilco

door i n t h e f a l s e c e i l i n g of t h e area between columns 8-9 and B-C i s used

for moving small equipment i n t o or out of t h e containment enclosure

-LJ

Table 4.3.

Auxiliary Cell Dimensions

Location

Inside Dimensions

~~~~

Concrete Wall Thickness

Floor

Thickness of Top Blocks (in.)

N - S

E - W

N - S xE - W

Elevation

Columns

( ft-in.)

(in.)

Fuel Processing Cell

4- 5

A - B

12~-10"x14'-3"

83i1-0"

18*

12*

Decontamination Cell

3 - 4

A - B

15'-O"x1k1-3"

832' -6"

Liquid Waste Cell

2 - 3

A - B

131-o"x2ii -0"

8281-0"

-3

C - D

13' - 0 ~ ~ ~-0"2 1

831 1 -0"

Hot Storage Cell**

3 - 4

C - D

15 1 - 0 ~ ~ 1~-3" 14

832 -6"

12*

Spare Cell

4 - 5

C - D

131- 6 1 i ~ 1 -3" 4

831 -0"

18*

Name of Cell

Remote Maintenance Cell 2

*Plus additional stacked blocks as required. *Whe hot storage cell is lined with 11 gauge SS to the elevation of 8361-6".

a 58 and f o r removal of fuel and coolant s a l t samples.

A 12-ft by 1 2 - f t

door located a t column l i n e 2 i s used f o r l a r g e r equipment removal. The framework of t h e high bay i s Stran S t e e l construction w i t h a 16-

gage mild i r o n sheet m e t a l skin skip-welded t o it. The cracks were sealed with f i b e r g l a s s tape and Carboline paint t o f a c i l i t a t e decon-

tamination. Emergency e x i t s are provided a t t h e southeast corner and near t h e center of t h e east w a l l .

Since t h i s area i s considered as a contami-

nated zone, normal entrance and e x i t i s through t h e hot change house located east of t h e high bay between columns 5 and 7 and through t h e regular change room. 4.3.10

Maintenance Control Room

A lg-ft-8-in.

by 14-ft-9-in.

maintenance control room i s located

along t h e w e s t s i d e of t h e high-bay containment between t h e reactor and d r a i n tank c e l l s . 870-1/2 f t .

The floor elevation i s 862 f t and t h e c e i l i n g

The west side i s corrugated asbestos t o match t h e building.

The roof i s 12-in.-thick concrete, t h e south s i d e 2-ft-thick concrete,

and t h e north and south s i d e s 3- t o 3-1/2-ft-thick

concrete for shielding.

A zinc-bromide-filled viewing window i s located on t h e w e s t s i d e near

t h e south end and another on t h e northwest corner of t h e room f o r use during remote maintenance.

Access t o t h e maintenance control room i s

v i a stairs which terminate a t ground l e v e l w e s t of t h e building. A 6-ft by lg-ft-8-in.

e l e c t r i c equipment room' located below t h e

maintenance room has a f l o o r elevation of 852 f t .

This i s accessible

through a hatch i n t h e southeast corner of t h e maintenance control room.

4.4 O f f - G a s Area The off-gas area consisting of a vent house and absorber p i t i s shown i n Fig. 4.4. The vent house i s 12 f t by 1 5 f t with an operating f l o o r l e v e l of

848 f t . The sloping roof attaches t o t h e south end of t h e 7503 building a t t h e 857-1/2-ft

elevation.

A 5-ft by 9-ft by 3-ft-deep containment enclosure i s located along

t h e east s i d e of t h e venthouse.

This contains t h e reactor and d r a i n

-t

tank off-gas l i n e s , instruments, valves, e t c . The bottom of t h i s enclosure i s a t t h e 839-1/2-ft elevation. The e a s t and w e s t sides a r e reinforced concrete, t h e north and south ends and t o p a t t h e 842-1/2-ft elevation a r e constructed of m i l d s t e e l angle i r o n s and 1/8-in. p l a t e

(ASTM A - 7 ) .

The j o i n t s are caulked t o prevent leakage.

Hand valves

have shielded extension handles which permit them t o be operated from t h e venthouse f l o o r .

Pipe caps a r e i n s t a l l e d f o r containment when t h e

valves a r e not being operated.

Five f e e t of barytes blocks a r e A lT-in.-diam removable

stacked on t o p of t h e containment enclosure.

plug i s i n s t a l l e d above t h e control valves and check valves t o f a c i l i t a t e remote maintenance. The west s i d e of t h e venthouse has a f l o o r elevation of 844-1/2 f t and i s used f o r off-gas l i n e s not requiring shielding and f o r stacked block shielding f o r t h e r e a c t o r and d r a i n tank off-gas l i n e s . A 5-ft by l 5 - f t valve p i t w i t h t h e bottom a t an elevation of 841 f t i s located south of t h e venthouse.

The off-gas l i n e s pass through

t h i s p i t before e n t e r i n g t h e absorber beds.

located i n t h i s p i t .

The o u t l e t l i n e s a r e also

The i n l e t valves a r e contained i n a 2-1/2-ft

4 - f t by 2-ft-high containment box which has a t o p elevation of 845-3/4 ft.

Seventeen inches of s t e e l p l a t e i s used above t h i s box f o r shielding.

Shielded extension handles permit operation of t h e valves from t h e opera t i n g f l o o r a t an elevation of 848 f t .

Pipe caps a r e i n s t a l l e d for

containment when t h e valves are not being operated.

The l i n e r between

t h e charcoal beds and t h e p i t go through a 9-in. by 18-in. penetration where they a r e grouted i n place using Embeco Expansion Grout. The charcoal bed p i t i s 10 f t i n s i d e diameter with lb-in.-thick concrete walls.

The bottom of t h e p i t i s a t an elevation of 823 f t 9 i n .

The p i t i s f i l l e d with water t o an e l e v a t i o n of 846 f t f o r shielding. Two l0-1/2-ft-diam

by 18-in.-thick bar>%esconcrete blocks a r e sup-

ported by a ledge a t t h e 846-1/2-ft elevation. caulked t o obtain a n a i r t i g h t s e a l .

The t o p block i s

Additional barytes concrete blocks

are stacked on t o p of these t o give a minimum of 5-l/2-ft

of shielding.

A 4 - f t annulus around t h e outside of t h e charcoal bed p i t i s f i l l e d with s t a b i l i z e d aggregate from t h e 848-ft t o t h e 849-ft-5-in.

elevation.

The off-gas from t h e charcoal bed goes through t h e valve p i t

mentioned previously, where unshielded extension handles permit operation from t h e 848-ft elevation.

4.5

Stack Area

The stack a r e a i s located south of Building 7503.

A l l off-gas

and containment v e n t i l a t i o n a i r passes through roughing and absolute f i l t e r s before being discharged up t h e containment stack. These containment s t a c k f i l t e r s a r e located i n a p i t 60 f t south The p i t i s 26-1/2 f t by 18-3/4 f t w i t h a sloping

of Building 7503. floor.

The f l o o r elevation a t t h e north end i s 850 f t and t h e south

end i s 848 f t .

The w a l l s a r e 1 - f t - t h i c k concrete.

The roof plugs

a r e 18-in.-thick concrete w i t h a 3-in. o f f s e t a t t h e center.

This

o f f s e t r e s t s on a ledge 9 i n . down from t h e t o p of t h e p i t .

The

elevation of t h e t o p of t h e p i t i s 857 f t .

The roof blocks a r e caulked

t o prevent leakage. A 3-ft-3-in.

by 5-ft-6-in.

valve p i t i s attached t o t h e f i l t e r p i t

on t h e southeast corner.

This houses t h e f i l t e r p i t d r a i n valves and

water l e v e l i n d i c a t o r s .

The w a l l s and removable roof plug a r e 8-in.-

t h i c k concrete.

The f l o o r and roof a r e a t 845 and 857-ft elevations.

The two 21,000-cfm containment v e n t i l a t i o n s t a c k fans and t h e associated 3-ft-dim by 100-ft-high s t e e l s t a c k a r e located south of the f i l t e r pit.

4.6 Vapor-Condensing Tanks The vapor-condensing system water tank, expansion tank, and associa t e d piping,

a r e located west of t h e s t a c k a r e a .

As mentioned previously,

t h e rupture d i s c s and connections t o t h e reactor c e l l exhaust duct are located i n t h e s p e c i a l e q u i p e n t room.

4.7 Blower House The blower house i s 36 f t by 43 f t w i t h f l o o r and c e i l i n g elevations of 838 and 856 f t , respectively. The north, south, and west w a l l s a r e louvered t o provide a i r i n l e t t o t h e two coolant blowers and two annulus blowers located i n t h e south half of t h e room.

The a i r from t h e blowers

passes through t h e r a d i a t o r a r e a of t h e coolant c e l l and out t h e 10-ft-

diam by 70-ft-high s t e e l stack located j u s t north of t h e venthouse. Top elevation of t h i s stack i s 930 f t .

61 Gas coolant pump No. 3, which supplies a r t o f r e e z e valves i n t h e coolant drain tank c e l l and f u e l processing c e l l , i s located between cohmn l i n e s 7 and 8.

A ramp leading t o t h e coolant drain tank c e l l begins a t t h e northwest corner of t h e blower house. The cooling water equipment room housing t h e cooling water control panel, storage tanks, flow meters, and t r e a t e d water c i r c u l a t i o n pumps i s located i n t h e southwest corner of t h e blower house.

The stairs leading t o t h e maintenance control room a r e located j u s t west of t h e blower house.

The area under t h e stairs i s used f o r

t h e f l u o r i n e gas trailer, hydrogen and hydrogen f l u o r i d e gas cylinders, e t c . , which are used i n processing t h e f u e l salt.

4.8 Store Room and Cooling Tower A 32-ft by 74-ft corrugated asbestos building located west of t h e blower house i s used as an ORNL substores.

Some of t h e switch gear

f o r t h e blowers i n t h e blower house a r e located i n t h i s building. The cooling tower and cooling tower pumps are located north of t h e s t o r e room.

The base f o r t h e cooling tower i s at t h e 845-1/2-ft

elevation, and t h e fans a r e a t 854 f t .

4.9 Diesel House The 3 O - f t by 72-ft d i e s e l house i s located 36 f t west of Building

7503 between column lines 3 and 5 and adjoins t h e switch house on t h e It has corrugated asbestos s i d i n g and a pitched roof with an

east.

e l e v a t i o n of 858 f t a t t h e c e n t e r and 852 f t a t t h e sides.

The t h r e e d i e s e l generator u n i t s and t h e i r auxiliaries a r e located a t t h e east end of the north half of t h e building. The 5000-gal d i e s e l f u e l storage tank i s located approximately 100 f t north of t h e diesel house. The helium cover-gas treatment equipment and emergency helium supply cylinders a r e located j u s t west of t h e d i e s e l s . The helium supply t r a i l e r i s located outside t h e west end of t h e building.

The tower-water-to-treated-water

heat exchanger i s located along

t h e west end i n s i d e t h e building. The instrument a i r compressors and a u x i l i a r y a i r compressor a r e along t h e south s i d e .

% t

4.10 Switch House and Motor Generator House The switch house, which i s 30 f t by 36 f t , adjoins t h e d i e s e l house on t h e west and Building 7503 on t h e e a s t .

It has corrugated

asbestos s i d i n g w i t h a f l a t roof a t t h e 852-ft elevation.

The f l o o r

elevation i s 840 f t . The main switch gear f o r t h e 480-v feeder l i n e s and t h e d i e s e l generator controls a r e located i n t h i s area. A l 5 - f t by 16-ft motor generator room, located north of t h e e a s t

end of t h e switch house and accessible from t h e switch house, contains two motor generators (MG1 and 4) and t h e i r control panels. The process power substation i s located west of t h e motor generator room.

4.11 I n l e t Air F i l t e r House The high-bay i n l e t a i r f i l t e r and steam-heating u n i t s a r e located i n t h e i n l e t f i l t e r house.

T h i s 1 2 - f t by 20-ft concrete block building

i s located j u s t north of t h e 7503 Building between column l i n e s 2 and 3 . The f l o o r elevation i s 840 f t 6 i n . , and t h e f l a t roof i s a t an e l e vation of 850 f t 11 i n .

... .

. .I_*

. .

___

. . .

..... ~..

.I_._

.- .,...

".~ .. .. ,

, .

5. FUEL CIRCULATING SYSTEM 5.1 Layout The f u e l c i r c u l a t i n g system consists of t h e reactor vessel, t h e f u e l pump, t h e heat exchanger, interconnecting piping, and a u x i l i a r i e s and services.

The major components of t h i s system are contained within

t h e reactor c e l l , as indicated i n Fig. 5.1 and Fig. 5.2,

ORNL Dwgs

. E-GG-A-40700 (plan) and E-GG-B-40701 (elev, ) .

and shown on

The f u e l pump bowl i s a t the highest elevation i n the primary circuc. A

l a t i n g system and serves a s an expansion volume f o r the s a l t .

The l e v e l of t h e molten-salt i n t e r f a c e i n the bowl i s an indication of t h e inven-

t o r y of t h e salt i n t h e system. The heat exchanger and a l l piping i n the c i r c u l a t i o n system p i t c h downward a t about 3" with the horizontal t o promote drainage of t h e s a l t t o the reactor vessel.

A drain l i n e from t h e bottom of t h e reactor

a l s o pitches downward a t 3" and leads t h e salt t o the drain tanks i n the adjoining c e l l ,

The l e v e l of radioactivity i n t h e reactor and drain tank c e l l s prevents d i r e c t approach f o r maintenance of equipnent.

The items most l i k e l y t o require servicing a r e therefore arranged t o be accessible from

above when using remotely operated tooling.

I n many cases t h e flanges, e l e c t r i c a l disconnects, e t c . , are provided with special bolting, clamps, and l i f t i n g bails t o f a c i l i t a t e remote manipulation.

Five frozen-seal type flanges ("freeze flanges") a r e provided i n t h e main f u e l and coolant s a l t c i r c u i t s t o allow removal and replacement of major components. The d r a i n l i n e from t h e reactor vessel can be cut and rejoined by brazing, using specially developed, remotely operated t o o l s and viewing equipment. The procedures used i n maintenance operations a r e f u l l y described i n P a r t X.

I n general, the thermal expansion i n the primary c i r c u l a t i n g loop i s accommodated by allowing t h e pump and heat exchanger t o move.

The coolant s a l t piping and the drain l i n e a r e s u f f i c i e n t l y f l e x i b l e i n themselves t o absorb t h e displacements.

The e f f e c t of temperature changes on piping and equipment movements and s t r e s s e s i s discussed subsequently i n Sec. 5.6.2.

f--

i :

w if

66 5.2

Flowsheet

A detailed process flowsheet of the f u e l c i r c u l a t i n g system i s shown

i n Fig. 5.3 (ORNL Dwg. AA-A-40880) .15 An explanation of t h e symbols used on the flowsheet i s given i n the Appendix. l i n e schedule,"

The data sheets,16 t h e

and the instrument application diagrams supply t h e

supplemental information needed f o r detailed study of t h e flowsheet. Thermocouple information i s tabulated on ORNL Dwg. A-AA-B-40511

(51

sheets). I n t h e following discussion of the process flowsheet shown i n Fig. 5.3, detailed descriptions of t h e reactor, heat exchanger, and pump a r e reserved f o r Secs. 5.3, 5.4, and 5.5. The instrumentation and controls

t. .i

a r e mentioned i n t h i s section only t o t h e extent necessary t o explain t h e flowsheet.

A detailed description of the instrumentation, including

t h e interlocking controls, e t c . , i s given i n Part 11, During operation of the reactor, f u e l salt i s circulated through t h e f u e l system a t a r a t e of 1200 gpm. The base pressure i n the system i s 5 psig--the pressure of the helium cover gas a t t h e surface of t h e

s a l t i n the pump bowl. A t design conditions of 10 Mw power l e v e l , f u e l e n t e r s the reactor a t 1175°F and 35 psig, flows through the reactor vessel and t h e reactor core, and leaves a t l225'F and 7 psig. It flows through l i n e 100 t o t h e suction of the f u e l pump and i s discharged by the pump through l i n e 1 0 1 t o the heat exchanger. The f u e l enters t h e s h e l l side of the heat exchanger at l225OF and 55 psig and leaves a t 1175'F and

35 psig. Coolant s a l t i s circulated through t h e tubes, entering at 1025°F and 77 psig and leaving a t llOOOF and 47 psig. Fuel from the heat exchanger i s returned t o t h e reactor vessel through l i n e 102.

The pipe

l i n e s i n the c i r c u l a t i n g system a r e a l l 5-in. sched-40 INOR-8 pipe, and t h e flow velocity i s about 20 f t / s e c .

The t o t a l volume of salt i n piping

and primary c i r c u l a t i n g system equipment under normal operating conditions i s about 73 f t3

Line lo3 i s provided t o drain t h e coqtents of t h e f u e l salt through freeze valve lo3 i n t o t h e f u e l drain tank system. An overflow tank under t h e pump bowl, and connected t o t h e bowl through l i n e 520, provides 5.5

f t3 of additional volume f o r expansion of salt and f o r protection against *

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68 o v e r f i l l i n g of the system.

The drain and overflow l i n e s are 1-1/2-in.

sched-40 INOR-8pipe. The reactor vessel i s i n s t a l l e d i n a s t a i n l e s s steel thermal shield that supports t h e reactor vessel and forms t h e outer w a l l of t h e reactor

furnace.

The thermal shield i s 16 i n . t h i c k and contains about 50$ s t e e l

and 5 6 water, which absorbs most of t h e neutron and gama ray leakage from t h e reactor.

Water c i r c u l a t e s through t h e shield a t a r a t e of 100 gpm

and removes 180 kw of heat.

It enters through l i n e 844 and leaves through

l i n e 845, with an estimated maximum temperature rise of 12'F.

The

t r e a t e d water supply i s described i n Sec. 15. A nuclear instrument thimble penetrates t h e w a l l of the reactor c e l l

I./'

vessel, the outer w a l l of t h e thermal shield, and terminates a t t h e inner This thimble i s f i l l e d w i t h water and contains two compensated ion

wall.

chambers, two f i s s i o n chambers, and t h r e e s a f e t y chambers f o r monitoring t h e nuclear performance of the reactor.

The inside of t h e thermal shield i s l i n e d with 6 i n . of high temperat u r e insulation, and the annulus between t h e reactor vessel and t h e i n s u l a t i o n contains 126 v e r t i c a l tubular heaters.

The heaters a r e divided

between three c i r c u i t s w i t h a t o t a l capacity of 60 kw. Temperatures a r e monitored a t 48 locations on t h e reactor vessel and t o p head assembly, most of which have spares, giving a t o t a l of 80 thermocouples (see ORNL Dwg. D-HE-B 40528)

. Temperatures a t 25 of these locations

a r e scanned continuously and a r e used as a guide t o control the operation of t h e heaters, A flanged nozzle on the t o p of t h e reactor vessel passes through t h e

t o p of the thermal shield and provides access t o the core f o r the control rod thimbies and f o r i n s e r t i o n of graphite and metal specimens f o r i r r a d i ation.

The access nozzle and plug a r e cooled by gas t o provide frozen

salt s e a l s i n the annulus between them and i n t h e sample port annulus. G a s coolant i s supplied through l i n e s 961, 962, and 963 a t a r a t e of 10

scfm through each and i s discharged d i r e c t l y t o the c e l l atmosphere.

Gas coolant f o r the t h r e e control rods i s supplied a t a r a t e of 1 5 scfm through

l i n e 915 and i s discharged t o the c e l l atmosphere through l i n e 956. Valves are provided i n t h e i n l e t and o u t l e t l i n e s t o block the flow and prevent f u e l s a l t from being discharged i n t o t h e c e l l i f a thimble develops a leak.

. . . ~. . . . .

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The system f o r c i r c u l a t i n g t h e cooling gas, which i s ~ 9 5 % nitrogen and

e$oxygen (and i s a l s o t h e atmosphere i n t h e reactor and d r a i n tank

c e l l s ) , i s described i n Sec. 16. The sample port i n t h e access nozzle opens i n t o t h e graphite sampler housing.

This i s a s t e e l tank i n which t h e atmosphere can be controlled

t o prevent the r e a c t o r and t h e samples from being contaminated by oxygen and moisture as the samples a r e t r a n s f e r r e d i n t o and out of t h e core. The t r a n s f e r must be done with t h e r e a c t o r shut down and drained.

Line

918 v e n t i l a t e s t h e sampler housing t o t h e reactor offgas system. Dry E?

helium o r nitrogen i s supplied t o t h e housing through t h e s e a l s on $he

cover.

Line 100 connects t h e o u t l e t of t h e r e a c t o r vessel t o t h e suction of c

t h e f u e l pump.

Thermocouples near t h e entrance t o l i n e 100 a r e used f o r

alarm and control c i r c u i t s and t o sense t h e r e a c t o r o u t l e t temperature, which i s recorded and logged on t h e data logger.

Line 100 has a f r e e z e

flange j o i n t (FF-100). The buffer zone of t h e r i n g j o i n t s e a l i s supplied w i t h helium and monitored f o r leakage through l i n e 410.

Three pairs of

thermocouples are i n s t a l l e d on t h e flanges with one thermocouple of each

pair serving as a spare.

Thermocouples a t two locations a r e connected

t o temperature switches t o annunciate an alarm i f t h e temperature f a l l s below a preset value (see Instrument Application Diagram, P a r t 11, o r

ORNL Dwg. D-AA-B-40500). c

The l e a k detector and thermocouple i n s t a l l a t i o n s

on FF-100 are duplicated on all other freeze flanges i n the r e a c t o r

system.

A pipeline h e a t e r of 4-kw capacity and a spare are i n s t a l l e d between 1

t h e r e a c t o r v e s s e l and FF-100. A similar h e a t e r of 4-kw capacity i s i n s t a l l e d on t h e horizontal s e c t i o n of t h e pipe between FF-100 and the pump bowl.

The v e r t i c a l s e c t i o n of pipe beneath t h e pump bowl i s i n t h e

pump furnace.

The pipeline heaters, described i n d e t a i l i n Sec. 5.6.4,

are small furnaces t h a t a r e assembled from ceramic heaters and r e f l e c t i v e i n s u l a t i o n and are made t o be e a s i l y removable f o r maintenance. Thermocouples a r e attached t o t h e pipe under each h e a t e r u n i t t o monitor t h e temperature and a r e used a s a guide t o control t h e heaters. The f u e l pump i s a v e r t i c a l sump-type pump t h a t c i r c u l a t e s 1200 g p m of s a l t against a head of 49 f t when operated a t a speed of 1150 rpm.

About 65 gpm i s recirculated i n t e r n a l l y i n t o t h e pump bowl, 1 5 gpm along

-=%Id

--1

t h e shaft and 50 gpm i n a spray i n t o t h e gas space, f o r removing krypton and xenon.

The l i q u i d l e v e l i n t h e pump bowl i s determined by means of

two bubblers.

H e l i u m i s introduced near t h e bottom of t h e pump bowl

through l i n e s 593 and 596.

Line 592 i s a reference l i n e t h a t connects t o

t h e expansion volume i n t h e pump bowl near t h e t o p and i s purged with helium t o prevent back diffusion of radioactive gases.

Signals from t h e

l e v e l indicators a r e monitored continuously, logged on t h e data logger, and used f o r alarm and control c i r c u i t s . The main purge of helium through t h e pump bowl e n t e r s through l i n e

516 j u s t below t h e lower shaft s e a l i n t h e bearing housing.

Most of t h e

gas flows downward through t h e labyrinth between t h e s h a f t and t h e s h i e l d

block i n t h e neck of t h e bowl t o prevent l a r g e amounts of radioactive gas from reaching t h e s e a l .

This helium combines with t h e helium from

t h e bubblers and c a r r i e s t h e radioactive gases out of t h e pump house through l i n e 522.

Line 522 i s enlarged from 1/2-in. pipe t o b i n . pipe

t o provide a holdup volume of 6 f t 3 and one hour of delay f o r t h e decay of t h e short-lived radioactive isotopes before t h e gas leaves t h e reactor c e l l and enters t h e offgas disposal system. i s described i n Sec. 10.4.

The helium supply system

The offgas system i s described i n Sec. 1 2 .

The d i s t r i b u t i o n of helium t o t h e pump i s l i s t e d i n Table 5.1, below. Table 5.1.

Distribution of Helium Supply t o Fuel Pump 5

Pum@bowl bubblers

Line 593 Line 596 Line 592

0.37 l i t e r / m i n 0.37 l i t e r / m i n

1300 l i t e r l d a y

0.15 l i t e r / m i n

Pump bowl purge - Line 516 Down shaft annulus Out l i n e 524

*0.1 l i t e r / m i n

3400 l i t e r / d a y

0.37 l i t e r / m i n 0.37 l i t e r / m i n

1300 l i t e r / d a y

’

Overflow tank bubblers Line 599 Line 600 Line 589

0.15 liter/min Total

6000 l i t e r / d a y

71 Line 521 connects t h e pump offgas l i n e t o t h e gas l i n e s i n t h e d r a i n tank system t o equalize t h e gas pressures i n t h e d r a i n tanks during normal

operation and f a c i l i t a t e t h e t r a n s f e r of gas between systems during a r e a c t o r drain. A small amount of helium t h a t e n t e r s t h e pump bowl through l i n e 516

flows upward through t h e labyrinth, combines w i t h a small amount of o i l that leaks through t h e lower shaft s e a l , and t h e mixture passes out of

t h e r e a c t o r c e l l through t h e lead-shielded (1-1/2) l i n e 524 t o the oil catch tank located i n t h e s p e c i a l equipment room.

After leaving the o i l

catch tank, t h e gas flows on t o t h e offgas system through l i n e 524, which

i s f i t t e d with a pressure reducing c a p i l l a r y , a f i l t e r , and a flow i n d i cating instrument. c

Signals from t h i s instrument i n i t i a t e an alarm i f t h e

flow i s outside a specified range. The maximum height of t h e l i q u i d l e v e l i n t h e pump bowl i s l i m i t e d by overflow i n t o l i n e 520, which connects t o a 5.5-ft 3 tank beneath t h e pump.

T h i s tank i s provided with helium bubblers that operate through l i n e s 599 and 600 and reference l i n e 589.

Indication of high l e v e l i n t h e overflow

tank causes t h e r e a c t o r system t o be drained.

Helium leaves t h e over-

flow tank through l i n e 523, which connects t o l i n e 522.

Valves HCV-523

and HV-523 a r e used t o block t h e vent l i n e so t h a t t h e overflow tank can be pressurized through t h e bubbler l i n e s and salt can be discharged t o t h e pump bowl. -*. 4

Line 999 connects t h e pump b o w l t o t h e sampler enricher.

Capsules

are used t o remove samples of f u e l f r o m t h e pump bowl through t h i s 1-1/2-in. l i n e , and small slugs of fuel may a l s o be added through it. The sampler enricher is described i n d e t a i l i n Sec. 7.0. The lower two-thirds of t h e pump bowl, t h e overflow l i n e and tank, and

t h e v e r t i c a l s e c t i o n of t h e suction l i n e t o t h e pump are i n s t a l l e d i n t h e pump furnace.

The furnace i s divided i n t o an upper zone around t h e pump

bowl and a lower zone around the overflow tank.

The upper zone has nine

v e r t i c a l t u b u l a r heaters with a t o t a l of 22.5-kw capacity, and t h e lower zone has f i v e similar, but longer, heaters with a t o t a l of 22.5-kw capacity. There a r e 22 thermocouples and

spares on t h e pump, eight thermocouples

on t h e overflow tank, and two thermocouples on l i n e 100 i n s i d e t h e furnace, f o r use i n monitoring t h e temperatures and c o n t r o l l i n g t h e heaters. E

72 The upper part of t h e pump bowl i s not cooled by t h e c i r c u l a t i n g f u e l salt and must therefore be cooled by gas c i r c u l a t e d over t h e outer surface of t h e pump bowl t o remove the heat generated by absorption of beta and gamma radiation.

The cooling gas i s supplied through 3-in.

l i n e 903 a t a maximum flow rate of 400 scfm.

The gas flow i s confined

by a shroud around t h e bowl and i s discharged t o t h e c e l l atmosphere. Temperatures of t h e t o p of t h e pump bowl and t h e flanged neck a r e used i n controlling t h e flow of coolant. O i l i s used t o cool and l u b r i c a t e t h e pump bearings and t o cool t h e

s h i e l d block i n the neck of t h e pump bowl.

Lubricating o i l f o r t h e

bearings enters t h e t o p of the bearing housing through l i n e 703 a t a r a t e of 4 gpm, and coolant f o r t h e s h i e l d block e n t e r s through l i n e 704 at a rate of 8 gpm.

O i l leaves t h e s h i e l d block through l i n e 707 and

passes through an eJector where it induces flow of o i l from t h e bearings through l i n e 705.

The combined flow leaves t h e pump through l i n e 706.

The temperature of t h e o i l supply i s 150°F and t h e r e t u r n temperature i s

160OF. Line 590 i s a breather pipe that connects t h e t o p of t h e l u b r i cating o i l supply tank t o t h e topmost passages i n t h e bearing housing t o equalize t h e pressure between t h e two points. o i l system a r e discussed i n See. 5.4.1.4.

Details of t h e l u b r i c a t i n g

Temperatures i n t h e o i l

system on t h e pump a r e monitored by two thermocouples on t h e o u t l e t o i l lines. The f u e l pump i s driven by a 75-hp, 1150-rpm, 440-v, three-phase e l e c t r i c motor.

The motor i s i n s t a l l e d i n a s t e e l housing that w i l l con-

t a i n o i l and radioactive gases i f e i t h e r o r both were t o leak through t h e upper s e a l i n t h e bearing housing.

The motor i s cooled by 5 gpm of process

water t h a t i s c i r c u l a t e d through a c o i l on t h e outside of t h e housing. Water e n t e r s t h e c o i l through l i n e 830 and leaves through l i n e 831. A microphone, XdbS, permits pump noises t o be monitored i n t h e control room. The e l e c t r i c a l input t o t h e pump motor i s instrumented f o r voltage,

current, and power readings.

The motor speed i s monitored and motor tem-

peratures a r e measured by a thermocouple ( w i t h spare). A l l t h e l i n e s t o t h e pump bowl have flanged j o i n t s , and t h e pump i s

assembled by means of two large flanged j o i n t s .

The r i n g - j o i n t s e a l s on

t h e flanges are connected t o t h e l e a k detector system (see Sec. 11.0).

rJ t

Fuel salt flows from the pump t o t h e heat exchanger through l i n e 101. The l i n e i s provided with a freeze flange j o i n t FF-101.

There a r e two

pipeline heaters, one of 4-kw and t h e other of 5-kw capacity, on t h e s e c t i o n of l i n e between t h e pump and t h e flange, and one 4-kw heater between t h e freeze flange and t h e heat exchanger.

Thermocouples a r e

attached t o t h e pipe under each heater t o monitor t h e temperature and a r e used as a guide t o control t h e heaters. The f u e l heat exchanger i s of t h e horizontal shell-and-tube type with t h e f u e l salt i n t h e shell and t h e coolant salt i n t h e tubes.

The

exchanger has t h r e e e l e c t r i c a l heater u n i t s that a r e similar i n construe-

The

t i o n t o those used on t h e pipelines but a r e considepably l a r g e r . t o t a l heater capacity i s 30 kw.

Sixteen thermocouples a r e d i s t r i b u t e d

between t e n locations on t h e heat exchanger s h e l l and nozzles.

Fuel s a l t

leaves t h e heat exchanger and returns t o t h e reactor i n l e t through l i n e 102.

Coolant salt e n t e r s through l i n e 200 and leaves through l i n e 201.

Freeze-flange disconnects FF-200 and FF-201 a r e i n s t a l l e d i n those l i n e s close t o t h e exchanger. Line 102 contains FF-102 t o j o i n t h e heat exchanger and r e a c t o r vessel.

The v e r t i c a l section of l i n e 102, d i r e c t l y below t h e heat

exchanger, i s heated by t h r e e calrod heaters that a r e attached permanently and have a capacity of 6 kw.

Three spare heaters with an addition-

a l 6 kw capacity a r e i n s t a l l e d on t h i s section of l i n e .

The horizontal

s e c t i o n of t h e l i n e t o t h e freeze flange has three removable p i p e l i n e heaters with a t o t a l of 16 kw capacity.

One pipeline heater of 4 kw

capacity i s provided between FF-102 and t h e thermal Shield. The temperatures on l i n e 102 a r e monitored by eleven thermocouples d i s t r i b u t e d between f i v e locations.

Four of t h e thermocouples a r e in-

stalled near t h e l o c a t i o n where t h e l i n e e n t e r s t h e thermal s h i e l d and

serve t o i n d i c a t e t h e f u e l temperature a t t h e i n l e t t o t h e r e a c t o r f o r

a l l control and s a f e t y purposes. S a l t i s introduced i n t o t h e primary c i r c u l a t i n g system o r drained from it through l i n e 103, which runs from t h e bottom of t h e reactor vessel i n t h e r e a c t o r c e l l t o t h e d r a i n tanks i n t h e d r a i n tank c e l l . 4.

The l i n e has a freeze valve, FV-103, t o provide "on-off" control of t h e

salt flow.

The valve i s located within t h e reactor furnace so t h a t i n

74 t h e emergency s i t u a t i o n of l o s s of e l e c t r i c a l power, t h e residual heat

i n t h e furnace w i l l be s u f f i c i e n t t o m e l t t h e salt i n t h e valve and cause t h e system t o drain.

A cooling gas stream of 25 t o 75 scfm i s supplied

through l i n e 919 and d i r e c t e d against t h e valve t o maintain a frozen plug of s a l t .

A l.5-kw e l e c t r i c a l heater i s i n s t a l l e d on t h e valve t o e f f e c t

a quick t h a w under normal circumstances. The freeze valve has t h r e e thermocouples, each w i t h a spare, t o monitor and control t h e operation of t h e cooling gas and t h e heater. Line lo3 i s insulated and heated by passing an e l e c t r i c current through t h e pipe w a l l .

The heating capacity i s 0 . 3 kw/ft, r e s u l t i n g i n a t o t a l

load of 17 kw.

The l i n e temperatures a r e monitored by twelve thermocouples.

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ORNL IlwG 64-8812

COOLING GAS OUTLET

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SALT OUTLET TO CIRCULATING PUMP SAMPLE HOLD-DOWN ROD UTLET STRAINER REMOVABLE GRAPHITE STRINGERS ( 5 )

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GRAPH IT€ STRINGERS 513 FULL SIZE 104 FRACTIONAL SIZE

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FILL AND DRAIN L I N E

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Unclassified

ORNL DWG 64-8813

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COOLANT GAS INLETS

CONTROL ROD DRIVE MOTOR HOUSING

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INOR-8

Reactor Vessel and Core Design Data and Dimensions

Construction material

Table 5.2.

I n l e t nozzle, sched-40, in., IPS

59-118 (60 i n . max) 58 9/16

Outlet nozzle, sched-40, i n . , IPS Core vessel OD, i n . ID, i n .

Wall thickness, i n .

Fuel i n l e t temperature, OF

Design temperature, OF

Design pressure, p s i

Head thickness i n .

1225

1175

50 1300

100-314

Fuel o u t l e t temperature, OF

Constant area distributor

6 of 5-in. nozzle)

Inlet

Overall height, i n . ( t o

Cooling annulus I D , i n .

56 58 Cooling annulus OD, i n .

L' $

55-114

Diameter, i n .

1140

Graphite core Number of f u e l channels (equivalent)

1 . 2 x 0.4 (rounded corners) Id, in.

56 114 68

55-112

Fuel channel s i z e , i n .

OD, i n .

Core container

Wall thickness, i n .

-e d

Height, i n .

IC;, CL

78 Table 5.2.

Reactor Vessel and Core Design Data and Dimensions

Construction material

INOR-8

I n l e t nozzle, sched-40, i n . , IPS

! i

-3 j{

Outlet nozzle, sched-40, i n . , IPS Core vessel OD, i n .

ID, in. Wall thickness, i n .

Overall height, i n . ( t o

L of 5-in. nozzle)

59-1/8 (60 i n . max) 58 9/16 100- 314

Head thickness i n .

Design pressure, p s i

50 1300

Design temperature, OF Fuel i n l e t temperature, Fuel o u t l e t temperature,

O F

1.175 1225

Inlet

Constant area distributor

Cooling annulus I D , i n .

56 58

Cooling annulus OD, i n .

u i .

c C

Graphite core Diameter, i n .

Number of f u e l channels (equivalent) Fuel channel s i z e , i n .

5544 1140 1 . 2 x 0.4 (rounded corners)

Core container Id, i n .

5542

OD, i n .

56 1/4 68

Wall thickness, i n .

Height, i n .

c;,

79 3ld

The reactor vessel 1-1/2-in.

sched-40 drain l i n e extends about

2-3/4 i n . i n t o t h e inside of t h e vessel at t h e c e n t e r l i n e and i s covered with a protective hood t o prevent debris on t h e bottom of t h e vessel from dropping i n t o t h e opening.

A 1/2-in.-dim

tube i s

mounted through t h e w a l l of t h e portion of t h e d r a i n l i n e protruding inside t h e vessel t o allow t h e s a l t t o d r a i n completely (see ORNL Dwg. D-BB-B-40405).

This tube extends through t h e d r a i n l i n e (103)

and t h e freeze valve, FV-103. -:

The core can, or s h e l l , i s 55-1/2 i n . I D and 67-15/16 i n . high and w a s r o l l e d from l/k-in.-thick 40410).

INOR-8p l a t e (see ORNL Dwg. D-BB-B-

The can i s supported, and a l s o held down when s a l t i s i n t h e

reactor, by a r i n g a t t h e t o p of t h e can which i s bolted t o 36 lugs welded t o t h e inside w a l l of t h e reactor vessel.

The can, i n turn,

supports t h e graphite used as a moderator material i n t h e reactor. The properties of t h e graphite a r e discussed i n Section 5.3.2. The reactor core i s formed of 513 graphite core blocks, or s t r i n g e r s , each 2 x 2 i n . i n cross section and about 67 i n . long, overall, mounted i n a v e r t i c a l close-packed array, as shown i n Figure 5.6 and ORNL Dwg D-BB-B-40416. periphery.

I n addition t h e r e a r e 104 fractional-sized blocks a t t h e

Half-channels are machined i n t h e four faces of each s t r i n g e r

t o form flow passages i n t h e assembly about 0.4 by 1 . 2 i n . i n cross section.

There are 1108 f u l l - s i z e d passages and, counting f r a c t i o n a l

s i z e s , t h e equivalent t o t a l of 1140 f u l l - s i z e d passages.

The dimensions

of these flow channels were chosen t o provide a passage t h a t would not be blocked by small pieces of graphite and a l s o t o obtain a nearly optimum r a t i o of f u e l t o graphite i n t h e core.

The volume f r a c t i o n of

f u e l i s 0.225; t h e mass of fissionable material i n t h e reactor i s near t h e minimum, and t h e e f f e c t of t h e f u e l soaking i n t o t h e pores i n t h e 20 graphite i s small. When not buoyed up by being immersed i n t h e fuel s a l t , t h e v e r t i c a l graphite s t r i n g e r s rest on a l a t t i c e of graphite blocks, about 1 by 1-5/8 i n . i n cross section, l a i d horizontally i n two l a y e r s

a t r i g h t angles t o each other (see ORNL Dwg. D-BB-B-40420).

Holes i n

t h e l a t t i c e blocks, with k8-30' t a p e r and 1.040 i n . i n smallest diam-

eter, accept t h e 1.000-in.-dim doweled section a t t h e lower end of c

UNCLASSIFIED ORNL-LR-DWG 56874R

MODERATOR STRINGERS SAMPLE PIECE

- I

FIG. 5.6. TYPICAL GRAPHITE STRINGER ARRANGEMENT

each s t r i n g e r with s u f f i c i e n t clearance t o allow both angular and l a t e r a l displacement.

The upper horizontal surfaces of t h e graphite

l a t t i c e bars and s t r i n g e r s a r e tapered s o t h a t salt w i l l not stand on them a f t e r a reactor drain. The l a t t i c e blocks a r e supported by a g r i d of 1/2-in. t h i c k

INOR-8p l a t e s , s e t on edge v e r t i c a l l y , and varying i n height from about 1-5/8 i n . a t t h e core periphery t o about 5-9/16 i n . a t the center. (See ORNL Dwg D-BB-B-40413). This supporting g r i d i s fastened t o t h e rc

bottom of t h e core can and moves downward as t h e can elongates on a temperature r i s e . The regular pattern of t h e graphite s t r i n g e r s i n t h e core i s disrupted a t t h e center where the control rod thimbles and the graphite and INOR-8samples a r e located, see Figure 5.7.

The control rod thimbles

a r e supported from above and t h e samples a r e supported from below when no s a l t i s i n t h e reactor. The INOR-8 and graphite samples a r e contained i n t h r e e baskets i n t h e l a t t i c e position shown i n Figure 5.7. Each basket can be withdrawn independently of t h e others. A basket must be i n place a t each of t h e t h r e e locations during reactor operation, however. Each basket i s formed of 1/32-in. -thick INOR-8plate, perforated w i t h 3/32-in.-diam

holes.

The t o p f i t t i n g i s d r i l l e d with 1/8-in.-diam

holes on 1/4-in. centers f o r c i r c u l a t i o n of t h e s a l t and i s provided w i t h a T-shaped l i f t i n g b a i l .

This b a i l permits t h e sample removing t o o l t o

r o t a t e as well as l i f t t h e basket f o r b e t t e r maneuverability.

The upper

portion of t h e basket assembly extends from 1/2 t o 1-in. i n t o t h e f u e l -

salt o u t l e t s t r a i n e r and i s held i n position by it. The lower end of t h e basket i s provided with an INOR-8 f i t t i n g , a l s o d r i l l e d with 1/8-in. diam holes, which, i n conjunction with t h e other two baskets, forms a dowel t o fit i n t o t h e lower graphite l a t t i c blocks i n t h e same manner as t h e graphite s t r i n g e r s previously described. Each basket contains four 0.250-in. - d i m x 5-1/2-ft long samples of

INOR-8and f i v e graphite sample bars, 0.250 i n . x 0.470 i n . , as shown i n Figure 5.8. The graphite bars are divided i n t o samples of varying length (up t o about 12 i n . ) , which l a i d end t o end t o t a l about 5-l/2 f t .

The

-I

1.2 -4

Unclassified

64-8814

I-**

TYPICAL FUEL PASSAGE

Nom STRINGERS NOS. 7.60 AND 61 (FIVE) ARE REMOVABLE

T" --

arrangement of t h e baskets and contents i s experimental i n nature and

w i l l be varied during operation of t h e MSRE.

A thermocouple i s i n s t a l l e d

on the hold-down rod t o indicate t h e s a l t temperature leaving the reactor. I n addition t o t h e graphite samples i n t h e baskets, t h e f i v e graphite stringers a t the center of t h e core can be removed, although w i t h considerable more d i f f i c u l t y .

indicated i n Figure 5.7.

The location of these s t r i n g e r s i s

The f i v e s t r i n g e r s a r e of a special design

(Types 7, 60 and 61 on ORNL Dwgs D-BB-B-40416, 40418 and 40581).

They

rb.

a r e 2-in. x 2-in. i n cross section but a r e 64-1/2 i n . long r a t h e r than the 62-1/8 i n . of the average s t r i n g e r .

They do not have t h e dowel

section a t t h e bottom and the hole f o r the hold-down rods and they r e s t

-l

d i r e c t l y on the INOR-8supporting grid r a t h e r than on the graphite l a t t i c e blocks.

The l a t t i c e blocks do not extend across t h e f i v e

s t r i n g e r locations, t h e opening thus provided through the blocks permitting insertion of a viewing device through t h e core to permit observation of the lower head should t h i s prove desirable. Each of t h e f i v e s t r i n g e r s i s d r i l l e d and tapped w i t h a 3/4-in.

6 Acme thread on the upper end f o r an INOR-8 l i f t i n g knob, o r stud, which can engage a Snaptite quick-disconnect coupling.

00 I

They a r e pre-

vented from f l o a t i n g i n t h e f u e l s a l t by 1/8 i n . x 1/2 i n . hold-down bars welded t o t h e s t r a i n e r assembly a t a l e v e l even w i t h t h e t o p of

the graphite core.

(See ORNL Dwg E-BB-B-40598).

The graphite core matrix i s s u f f i c i e n t l y unrestrained so t h a t on

a temperature r i s e the induced s t r e s s e s due t o expansion of t h e graphite w i l l be minimized. The coefficient of expansion f o r t h e graphite i s 1.3 -6 in./in.-OF t o 1 . 7 x 10 in./in.-OF, whereas f o r INOR-8 it i s 7.8 x ( i n the 70-1200°F range),

This difference causes the core can t o move

3/16 i n . r a d i a l l y away from the graphite core blocks on heatup of t h e reactor.

To prevent an excessive amount of salt flow i n t h e annuluar

space thus created, an INOR-8r e s t r i c t o r ring, 1/2 x 1/2 x 54-1/2 i n .

cjr

I D , surrounds t h e bundle of graphite s t r i n g e r s a t the bottom (see ORNL Dwg. D-BB-B-40427). The s t r i n g e r s are restrained from excessive

arrangement of the baskets and contents i s experimental i n nature and

w i l l be varied during operation of t h e MSRE.

The sample baskets a r e held down by a cup mounted on a 5/16-in. diam rod which i s an extension of the nozzle access plug, as shown i n Figure 5.4. The cup r e s t s on the T-shaped l i f t i n g b a i l s . A thermocouple i s i n s t a l l e d on the hold-down rod t o indicate t h e s a l t temperature leaving the reactor. I n addition t o the graphite samples i n t h e baskets, t h e f i v e graphite s t r i n g e r s a t the center of t h e core can be removed, although w i t h considerable more d i f f i c u l t y .

The location of these s t r i n g e r s i s

indicated i n Figure 5.7. The f i v e s t r i n g e r s a r e of a special design (Types 7, 60 and 61 on ORNL Dwgs D-BB-B-40416, 40418 and 40581). They 5.

a r e 2-in. x 2-in. i n cross section but a r e 64-1/2 i n . long rather t h a n the 62-1/8 i n . of the average s t r i n g e r . They do not have the dowel section a t t h e bottom and t h e hole f o r t h e hold-down rods and they r e s t

d i r e c t l y on t h e INOR-8supporting grid rather than on t h e graphite l a t t i c e blocks.

The l a t t i c e blocks do not extend across t h e f i v e

s t r i n g e r locations, t h e opening thus provided through t h e blocks permitting i n s e r t i o n of a viewing device through t h e core to permit observation of the lower head should this.prove desirable. Each of t h e f i v e s t r i n g e r s i s d r i l l e d and tapped with a 3/4-in.

6 Acme thread on t h e upper end f o r an INOR-8l i f t i n g knob, o r stud, which can engage a Snaptite quick-disconnect coupling.

They a r e pre-

vented from f l o a t i n g i n t h e f u e l s a l t by 1/8 i n . x 1/2 i n . hold-down bars welded t o the s t r a i n e r assembly at a l e v e l even with t h e t o p of t h e graphite core.

(See ORNL Dwg E-BB-B-40598).

The graphite core matrix i s s u f f i c i e n t l y unrestrained so that on

00 I

I\*

a temperature rise t h e induced s t r e s s e s due t o expansion of t h e graphite w i l l be minimized.

The coefficient of expansion f o r t h e graphite i s 1.3

-6 t o 1 . 7 x 10 in./in.-OF,

whereas f o r INOR-8 it i s 7.8 x

( i n the 70-1200°F range).

This difference causes t h e core can t o move

in./in.-v

3/16 i n . r a d i a l l y away from the graphite core blocks on heatup of t h e reactor.

To prevent an excessive amount of salt flow i n t h e annuluar

space thus created, an INOR-8r e s t r i c t o r ring, 1 / 2 x 1/2 x 54-1/2 i n . cjr

I D , surrounds the bundle of graphite s t r i n g e r s a t the bottom (see ORNL Dwg. D-BB-B-40427).

The s t r i n g e r s a r e restrained from excessive

. P

85 movement a t t h e t o p by a graphite r e t a i n e r ring, 1 x 2 x 53-1/4 i n . ID.

This ring, i n turn, i s held i n place by an INOR-8r e t a i n e r ring,

3/4 x 3/4 x 53-1/4 i n . I D (see ORNL Dwg. D-BB-B-40428 f o r both r i n g s ) . A t t h e t o p of t h e graphite blocks a centering bridge holds a row of

s t r i n g e r s i n p o s i t i o n on two diameters a t r i g h t angles t o each other. T h i s bridge helps t o prevent s h i f t i n g of t h e e n t i r e s t r i n g e r assembly

(see ORNL Dwg. D-BB-B-40424)

A 5/16-in. - d i m INOR-8rod passes through a 0.010-in. -wall-thickness I 4

bushing placed i n a 0.375-in.-diam

hole i n t h e dowel s e c t i o n a t t h e

bottom of each graphite s t r i n g e r .

These rods a l s o pass through t h e

INOR-8 grid-supporting s t r u c t u r e and prevent each graphite s t r i n g e r from f l o a t i n g i n t h e f u e l s a l t . L

If a graphite s t r i n g e r were t o break

i n two, t h e t o p portion would tend t o f l o a t away and leave a r e l a t i v e l y stagnant pocket of f u e l s a l t which might reach a higher temperature than desired.

The e f f e c t of t h i s on t h e r e a c t i v i t y and on t h e tempera-

t u r e s i n t h e r e a c t o r has been studied.*

To guard against t h i s eventu-

a l i t y , a 1/16-in.-diam INOR-8 wire i s passed through a l/8-in.-diam

INOR-8i n s e r t about 1 i n . from t h e t o p of each graphite s t r i n g e r , f a s t e n i n g t h e tops together and t o t h e core can. To prevent possible overheating i n a region that might otherwise have been stagnant, about 24 gpm of t h e salt entering t h e r e a c t o r i s diverted i n t o t h e region j u s t above t h e core-can support flange i n t h e annulus between t h e pressure vessel ami t h e core can.

This i s accom-

plished through 18 s l o t s o r channels, 0.2 by 0.2 i n . , cut i n t h e corecan flange.

These s l o t s a r e machined at an angle of 30" t o promote

b e t t e r miximg i n the region.

I n addition, a by-pass flow of 3-22 gpm

of salt w i l l pass through t h e annular clearances a t t h e core can support ring. 39 The salt leaves t h e r e a c t o r core and flows through t h e upper head t o t h e 10-in. nozzle opening.

It i s diverted through a 5-in.

*If a graphite s t r i n g e r were t o break i n two near khe center of t h e core and t h e upper half f l o a t e d away, t h e r e a c t i v i t y increase would be 0.004$ 6k/k for each 1 i n , of s t r i n g e r replaced by t h e f u e l . If t h e e n t i r e c e n t r a l s t r i n g e r were replaced by f u e l , t h e r e a c t i v i t y i n crease would be only 0.1% 6k/k and no power o r temperature excursion of consequence should r e s u l t .

86 opening i n t h e s i d e of the nozzle t o flow t o the f u e l c i r c u l a t i n g pump. The 10-in. nozzle a l s o serves as an access port and support f o r t h e t h r e e control rods and f o r taking and placing of t h e four graphitesample rods i n t h e core matrix.

A s t r a i n e r made from 16-gage INOR-8

p l a t e , with a staggered p a t t e r n of 3/32-in.-diam

holes on 9/64-in.

centers, i s b u i l t i n t o t h e t o p head and access plug assembly t o prevent l a r g e chips of graphite from c i r c u l a t i n g w i t h the f u e l s a l t . The control rods a r e discussed subsequently i n Section 5.3.5 and t h e graphite sampler i n Section 5.3.6. 5.3.2

Graphite A moderator i s d e s i r a b l e i n a molten-salt type r e a c t o r t o achieve

good neutron economy and low inventory of f i s s i l e material.

It i s

p a r t i c u l a r l y desirable that t h e moderator be used without cladding i n order t o obtain high breeding o r conversion ratios. Graphite i s compatible with molten s a l t , making it possible t o design t h e

MSRE with a heterogeneous type core, using unclad graphite a s t h e

moderator. A 2 by 2-in. cross s e c t i o n w a s adopted f o r t h e graphite core

s t r i n g e r s i n t h e MSRE l a r g e l y because it was believed that t h i s w a s about t h e l a r g e s t s i z e of high-density low-permeability graphite of reactor grade t h a t could be made a v a i l a b l e within a reasonable 20 amount of development time. The graphite f o r t h e MSRE w a s ordered from t h e National Carbon Company (New York),21 t h e only bidder, t o ORNL Specification MET-HM-1. I

The graphite i s a special grade, given t h e designation "CGB" by t h e

National Carbon Company, and new techniques and f a c i l i t i e s were required t o produce it. The graphite manufactured f o r t h e MSRE s a t i s f i e d a l l t h e requirements of t h e s p e c i f i c a t i o n s except f o r freedom from cracks and spalls.

Some of t h i s graphite was examined and t e s t e d ,

and the a c t u a l requirements of the MSRE were c a r e f u l l y restudied, w i t h t h e r e s u l t that material with some cracks and spalls w a s accepted 22

f o r use i n t h e reactor.

The physical and mechanical properties of t h e MSRE graphite are summarized i n Table 5.3.

The graphite i s discussed i n d e t a i l i n

P a r t I V , but some of t h e features, p a r t i c u l a r l y those r e l a t i n g t o t h e design, a r e b r i e f l y mentioned here.

87 Table 5.3.

Properties of MSRE Core Graphite - CGB

Physical Properties: BU density, g/m3 Porosity Accessible ( t o kerosene), $ Inaccessible, $

7*9 9.8 17.7

Total,

Them& conductivity, Btu/ft -hr-OF

With grain at 68°F (calculated) Normal t o grain at 68°F (calculated) 9

Temp. coefficient of expansion, i n . / i n . OF

With grain at 68°F Normal t o grain at 68°F

. L

116 63

0.56 x 1%-6

1.7 x io

Specific heat, Btu/lb-"F 0°F 200°F 600°F 1000°F 1200°F

0.14 0.22 0.33 0.39 0.42

Matrix coefficient of ermeability t o helium at 70°F, cm2$ec S a l t absorption a t 150 psig, vol $ Mechanical Strength (at 68°F) : T e n s i l e strength, psi With g r a i n Normal t o grain

3 0.20

Flexural strength, p s i With grain

Normal t o grain Modulus of e l a s t i c i t y , p s i With grain Normal t o grain Compressive strength, p s i chemical Purity: Ash, w t $ Boron, w t 4 Vanadium, w t 6 Sulfur, w t 4 Oxygen, cc of cd/100 cc graphite

0.0005 . 0 .oooo8

0 .000g 0.0005

6 .o

Irradiation Data: (Exposure: 1.65 x 10" nvt, 0.1 MeV) With grain Across g r a i n Shrinkage, $ -0.34 -0.24 650 700"c lO€?O"C -0 .og +o.io t o -0.07

88 Use of unclad graphite i n t h e MSRE required t h a t t h e graphite be compatible with t h e f u e l salt, f i s s i o n products, and INOR-8. The graphite must not introduce prohibitive amounts of contaminants, such as oxygen, i n t o t h e system.

Further, t h e graphite must not

d i s i n t e g r a t e o r undergo excessive dimensional changes and d i s t o r t i o n .

I t s thermal conductivity should not decrease t o o much with time.

A most important c h a r a c t e r i s t i c i s t h a t t h e penetration of s a l t i n t o

t h e voids i n t h e graphite be a minimum, since t h i s degree of salt permeation determines t h e graphite temperature both during operation and a f t e r shutdown.

The extent of absorption of fission-product

gases i s of concern i n t h a t t h e 135Xe contributes s i g n i f i c a n t l y t o t h e poison fraction. 23 Both in-pile and out-of-pile loop and capsule t e s t s demonstrated t h a t t h e r e need be no concern f o r solution of t h e graphite by the s a l t , and t h a t t h e r e are no apparent corrosion problems. 24

Other t e s t s demonstrated t h a t the d i s i n t e g r a t i o n of the graphite does not occur w i t h o r without chemical additions of f i s s i o n products, e i t h e r i n or

out of a radioactive e n ~ i r o n m e n t . ~Although ~ t h e temperatures are not thought high enough t o cause t h e graphite t o carburize t h e INOR-8,where t h e two a r e i n d i r e c t contact and there i s any likelihood of f a i l u r e of the INOR-8due t o embrittlemerit, an INOR-8i n s e r t has been placed between t h e load carrying piece and t h e graphite. The graphite w i l l be c a r e f u l l y heated i n dry helium t o desorb water vapor a f t e r i n s t a l l a t i o n i n t h e reactor.

A purge s a l t w i l l be

thoroughly c i r c u l a t e d through t h e primary system t o remove a l l but t r a c e amounts of oxygen before any f u e l s a l t i s introduced. It i s estimated t h a t the oxygen i n compounds i n the CGB graphite and i n the oxide f i l m on the INOR-8surfaces, does not exceed about l3O ppm of t h e purge salt, by weight.

The purge s a l t , on an as-received basis, i s estimated t o contain no more than 200 ppm of oxide ion; thus, t h e

s a l t , with i t s oxide s a t u r a t i o n l i m i t of about 1000 ppm, can reduce t h e oxygen i n t h e primary system t o s a t i s f a c t o r y l e v e l s before t h e uraniumbearing s a l t i s added. 25, 26, 27 The thermal conductivity of t h e graphite w i l l probably decrease by about a f a c t o r of three, based on data taken i n high-temperature

irradiation tests.

This loss was taken i n t o account i n t h e reactor

design and an even g r e a t e r reduction could be t o l e r a t e d without encountering undue d i f f i c u l t i e s . 23 Shrinkage i n t h e graphite w i l l occur i n proportion t o t h e i n t e grated fast neutron flux.

The radial f l u x gradient i n t h e core w i l l

cause t h e inner s t r i n g e r s t o shorten at a g r e a t e r r a t e , r e s u l t i n g i n t h e t o p of t h e graphite core matrix gradually becoming s l i g h t l y dished. Based on data taken on similar graphite, t h e a x i a l shrinkage r a t e of a z

s t r i n g e r located a t t h e point of maximum f l u x i n t h e MSRE f o r one year of operation a t t h e 10-Mw r e a c t o r power l e v e l w a s estimated t o be 0.14 in./yr.

The radial shrinkage was estimated t o be roughly one-half of

that i n t h e axial d i r e c t i o n .

The radial f l u x gradient i n t h e core w i l l

cause uneven shrinkage i n each s t r i n g e r , and t h e r e s u l t i n g unsymmetrical A

d i s t r i b u t i o n of s t r e s s e s w i l l tend t o bow t h e s t r i n g e r s outward t o give

a s l i g h t b a r r e l shape t o t h e core.

The maximum bowing e f f e c t w a s e s t i -

mated t o be about 0.1 in./yr f o r a s t r i n g e r a t t h e point of maximum f l u x and with continuous operation a t 10 Mw.

The widening of t h e f u e l

passages, and o t h e r r e l a t e d e f f e c t s of graphite shrinkage, were studied from t h e nuclear standpoint and found t o amount t o changes i n t h e react i v i t y e f f e c t of l e s s than 0.e Ak/k per year of full-power operation, and a r e not of consequence. 28, 29 The nuclear aspects of graphite 7

shrinkage a r e discussed i n d e t a i l i n Section 14.2 of P a d 111. I n designing t h e graphite s t r i n g e r s f o r s t r e s s e s induced by t e m perature gradients, it was decided t o l i m i t t h e r a t e of temperature rise t o about 60OF/hr.

Preheating i s accomplished by c i r c u l a t i o n of helium

i n t h e primary system, using t h e f u e l pump as a n i n e f f i c i e n t blower.

Heat i s introduced through use of t h e e l e c t r i c resistance heaters i n s t a l l e d throughout t h e primary and secondary systems. 30 Even though t h e MSRE grgrphite has a density of about 1.87, it cont a i n s about 1% by volume of t o t a l voids and @ by volume of voids t h a t

are interconnected and accessible from t h e surface.

The graphite, as

produced f o r t h e MSRE, however, has pore openings that average less than

0.3 p in diamter.

Since t h e salt does not wet t h e graphite, t h e surface

tension and contact angle a r e such as t o l i m i t t h e salt penetration t o l e s s than t h e permitted amount of 0.5$ by volume of t h e graphite a t 165

90 psia.

The heat produced i n t h e graphite by t h i s quantity of f u e l salt

$Id

under full-power conditions of 10 Mw increases t h e average graphite temperature by about 1”F.31 Fission products entrapped i n t h e graphite with the salt w i l l continue t o generate heat a f t e r t h e remainder of

t h e f u e l salt has been drained from t h e reactor.

With t h e cooling

medium thus withdrawn, and with no other means of heat removal e f f e c t i v e ,

it has been estimated that t h e temperature r i s e of t h e graphite would 32 be l e s s than 100°F i n 48 hr. Despite t h e considerable amount of preliminary t e s t i n g expended i n development of a graphite f o r use i n t h e MSRE, it i s recognized that some uncertainties e x i s t that can be resolved only by operation

of t h e reactor.33

The behavior of t h e graphite w i l l be monitored by

periodic removal and examination of samples placed near t h e center of t h e core.

Full-sized pieces located i n t h e core adjacent t o t h e

samples can be examined i n place by means of a periscope, or can be withdrawn infrequently f o r hot-cell examination by removing t h e

reactor vessel access nozzle plug and control rod thimble assembly.

5.3.3 Fluid Dynamics, Temperature Distribution, and Solids Deposition 5.3.3.1 General. A general description of t h e flow through t h e reactor vessel and core i s given i n Section 5.3.1. Models were used t o investigate t h e f l u i d dynamics and heat t r a n s f e r within t h e reactor vessel, but p r i o r t o these studies, several

decisions were made e a r l y i n t h e project t o i n i t i a t e t h e design e f f o r t . One of these w a s t o choose a r i g h t c y l i n d r i c a l shape f o r t h e vessel, mainly because of t h e ease of manufacture and because t h e flow p a t t e r n could be f a i r l y w e l l predicted,

Preliminary studies of t h e vessel

s i z e as a function of the c r i t i c a l mass required indicated an acceptable diameter range of 4 t o 5 f t .

A r e l a t i v e l y large mass flow r a t e

w a s decided upon i n order t o obtain hydraulic c h a r a c t e r i s t i c s more nearly approximating those t h a t would e x i s t i n a f u l l - s c a l e reactor. Early studies, subsequently confirmed, indicated a reasonable -temperat u r e r i s e f o r t h e salt passing through t h e reactor i f t h e flow rate 20 were 1200 gpm. Another e a r l y decision was t h a t t h e flow should be upwards through t h e core i n order t o f a c i l i t a t e removal of gases from t h e core passages

;

91 and upper plenum.

Preliminary estimates of t h e heat generation rate

i n t h e reactor vessel w a l l indicated that cooling would be necessary. It appeared b e s t t o cool t h e w a l l with t h e incoming f u e l , by c i r c u l a t -

i n g t h e salt between t h e vessel wall and t h e reactor core container can.34

Because of t h e heat generation within t h e salt i.n t h i s annulus,

t h e so-called Poppendiek e f f e c t , 35 flow r a t e s well within t h e turbulent range were needed.

T h i s l e d t o adoption of t h e s p i r a l flow p a t t e r n i n

t h e annulus and t h e annulus width, somewhat a r b i t r a r i l y taken, of 1 i n . 34 Regularly shaped, f l a t passages through t h e graphite were selected

j z

as being b e t t e r than c i r c u l a r ones i n reducing r a d i a l temperature gradiL

ents.

This geometry a l s o reduces t h e tendency of t h e salt, with a

Reynolds number i n t h e t r a n s i t i o n region, t o f l u c t u a t e between laminar and turbulent flow a s t h e Reynolds number increases w i t h temperature i-

during passage through t h e core. 36 5.3.3.2

Model Studies.

One-fifth and f u l l - s c a l e model s t u d i e s were

made, t o i n v e s t i g a t e t h e flow d i s t r i b u t i o n i n t h e reactor, t o v e r i f y the pressure drop estimates, and t o study t h e s e t t l i n g of s o l i d s o r sludge and t h e efficacy of i t s removal through the reactor drain l i n e .

Heat

t r a n s f e r studies were a l s o made through use of a heat meter. 37 The small model w a s made of c l e a r p l a s t i c and used water as t h e c i r culating fluid.

The f u l l - s c a l e model, Fig. 5.9, was made of carbon s t e e l

with aluminum core blocks. s t

Water was used as t h e c i r c u l a t i n g f l u i d i n

t h e f i r s t t e s t runs of t h e f u l l - s c a l e model; l a t e r , a g e l w a s added t o t h e water t o duplicate t h e v i s c o s i t y (but not t h e density) of t h e f u e l s a l t a t operating temperature.

A l l t e s t i n g w a s at room temperature

with e s s e n t i a l l y no heat t r a n s f e r t o o r from t h e c i r c u l a t i n g l i q u i d . Both models were f l u i d dynamically similar t o t h e reactor system, operated

a t t h e same Reynolds number as t h e salt, and could be r e l a t e d with simple proportionality constants.

The f u l l - s c a l e model served t o r e f i n e t h e data

taken from t h e one-fifth-scale i n s t a l l a t i o n .

There were no major differen-

ces between t h e findings from t h e two models, most variations being due t o t h e d i f f i c u l t y of obtaining good geometric s i m i l a r i t y i n t h e small model.

5.3.3.3

Overall Pressure Drop Across Reactor.

The o v e r a l l pres-

sure drop from t h e reactor vessel i n l e t t o t h e o u t l e t was measured on t h e f u l l - s c a l e model and found t o be about 9.2 f t o r f l u i d a t a

c L

Fig. 5.9.

Full-scale Model of Reactor Vessel.

flow r a t e of 1200 a m .

The overall pressure drop varied a s t h e square

of t h e flow r a t e , a s shown graphically i n Fig. 5.10.

An o v e r a l l pressure

drop very nearly proportional t o t h e velocity squared implies t h a t t h e controlling pressure l o s s ( i n t h e flow d i s t r i b u t o r ) i s almost independent of t h e Reynolds number over t h e range of flows t h a t a r e of i n t e r e s t . 38

. I

5.3.3.4 Flow Distributor. The flow d i s t r i b u t o r was described i n Section 5.3.1. Full-scale model studies showed t h a t t h e centerline v e l o c i t y i n t h e d i s t r i b u t o r varied from 9 t o 23 fps, a s shown graphically i n Fig. 5.11. The increase i n v e l o c i t y immediately following t h e i n l e t opening i s due t o t h e r e c i r c u l a t i o n of l i q u i d around t h e d i s t r i b u t o r .

Within t h e limits of experimental error, t h e velocity decreased l i n e a r l y with distance from t h e i n l e t , indicating t h a t t h e flow was being dist r i b u t e d uniformly t o t h e cooling annulus around t h e circumference of t h e vessel. Based on an equivalent diameter of 5 . 1 i n . f o r t h e d i s t r i b u t o r , t h e

Reynolds number i s e s s e n t i a l l y equal t o 1.29 x 10 per f t / s e c of velocity. The residence time of t h e f u e l i n t h e d i s t r i b u t o r i s -1.1 sec, and t h e average temperature increase i s estimated t o be only 0.004OF a t r a t e d conditions ( s e e Chapter 11, Ref. 18). The 3/4-in.-diam holes through which t h e f u e l s a l t flows from t h e d i s t r i b u t o r t o t h e annular space i n t h e v e s s e l are d r i l l e d a t an angle of 30' with a tangent t o t h e v e s s e l t o conserve much of t h e circumf e r e n t i a l v e l o c i t y developed i n t h e d i s t r i b u t o r .

The v e r t i c a l rows of

holes a r e spaced 5'

apart at t h e upstream end, but t h e spacing i s in-

creased t o 22 1/2'

a t t h e downstream end because t h e f l u i d s t a t i c

pressure i s greater.

A t r a t e d flow of 1200 gpm, t h e v e l o c i t y through

t h e upstream holes i s estimated t o be -3.7 fps, and a t t h e downstream holes i s -18.5 spectively.

5.3.3.5

fps,

giving Reynolds numbers of 7050 and 35,250, re-

(See Chapter I1 of Ref. 18.) Cooling Annulus.

A s t h e f l u i d moves downward i n t h e wall-

cooling annulus, t h e s w i r l component of t h e v e l o c i t y decreases and t h e t o t a l v e l o c i t y becomes l e s s .

(The t o t a l v e l o c i t y i s t h e vector

sum of t h e axial and circumferential components.)

The midplane

velocity of 5 . 1 fps gives a Reynolds number of 25,800 and an e s t i mated heat t r a n s f e r coefficient of 2090 Btu/hr-ft2-?.

A t design

bi c

UNCLASSIFlED ORNL- LR- DWG 78809 20

MEASURED WITH HIGH-RANGE DIFFERENTIAL PRESSURE CELL MEASURED WITH LOW-RANGE DIFFERENTIAL PRESSURE CELL

-._ 0

3 -

r L

c r

W LL 0

v) LL

L n 0

u 0

W LL

W v)

0.5

I LL W

0 >

0.2

n -.r.

2000

4000

500

200

4 00

FLOW RATE (gpm)

Fig. 5.10. Pressure Drop Through Reactor Core.

W 0

5 16 >

s W

> 12

0 0

4 35

(80

225

270

315

360

8. ANGLE FROM INLET TANGENT (deg)

Fig. 5.11. Center-Line Velocity Distribution i n Volute of MSRE F u l l Scale Core Model.

power of 10 Mw t h e average heat generation i n t h e vessel w a l l i s estimated t o be 0.054 w/cc.

The temperature difference between t h e

inside w a l l surface and t h e bulk f u e l temperature i s thus only about 0.12oF (Chapt. 11, Ref. 18). The lowest t o t a l v e l o c i t y i s a t t h e bottom of t h e annulus and i s estimated t o b e d 4 . 2 f p s , a value t h a t i s e s s e n t i a l l y constant

around t h e circumference. The residence t i m e i n t h e annulus i s estimated t o be 2.43 sec and t h e temperature increase t o b e ~ 1 , 1 3 " Fa t r a t e d power and flow rate (see Chapt

. I1 of Ref. 18). A conservative estimate i s t h a t

t h e pressure-vessel w a l l i s cooled t o an average temperature of no more than 5'F above t h e bulk temperature of t h e entering s a l t (1175°F).

5.3.3.6

Lower Head.

After leaving t h e cooling annulus t h e

fuel salt e n t e r s t h e lower head of t h e vessel, which serves as a

plenum i n which t h e s a l t i s d i s t r i b u t e d t o t h e reactor core passages. The 48 vanes i n t h e head have a r a d i a l length of about 11 i n . , or about 3@ of t h e vessel radius.

The vanes check t h e s w i r l developed

i n t h e annulus t o reduce t h e r a d i a l f l u i d pressure gradient i n t h e lower head t o l e s s than 2 i n . of f l u i d .

This small gradient i s

judged t o have a negligible e f f e c t on t h e d i s t r i b u t i o n of t h e f u e l t o t h e core passages (Chapt. 11, R e f . 18). Fluid age measurements were made throughout t h e lower head on

t h e one-fifth-scale model by use of s a l t conductivity techniques. A salt solution w a s added suddenly t o t h e c i r c u l a t i n g f l u i d j u s t up-

stream of t h e model i n l e t and changes of conductivity were measured

by numeruus probes i n t h e lower head.

Although these values were

taken from t h e s m a l l model i n which good hydrodynamic s i m i l a r i t y w a s d i f f i c u l t t o obtain, they lead substance t o t h e q u a l i t a t i v e conclusion t h a t t h e region of t h e lower head with t h e highest combination of

f u e l - s a l t residence t i m e , power density, and nuclear importance, i s a t t h e centerline. The i n t e g r a l residence time of t h e fuel s a l t i n t h e lower head

i s estimated t o be about 4.2 sec, and t h e i n t e g r a l average temperature increase i s about O.5"F a t rated flow and power.

97 Heat t r a n s f e r measurements were made i n t h e lower head of both t h e small and f u l l scale models.

The l a t t e r appeared t o give t h e

most r e l i a b l e r e s u l t s and indicate a heat t r a n s f e r coefficient of about 1500 Btu/hr-ft2-'F

a t a point about 17 in. r a d i a l distance from t h e

outer circumference.

This value i s based on both heat meter measure-

m e n t ~ ~ calculations which make use of t h e measured v e l o c i t y and~ on profiles.

The heat t r a n s f e r coefficient, based only on heat meter

measurements, a t a radius of 4 in. from the center of t h e head was indicated t o be about 900 Btu/hr-ft2-OF.

(See Chapter I1 of Ref. 18.)

The average heat generation within the w a l l of t h e lower head was estimated t o be 0.61 w/cc.

If t h e walls were so insulated t h a t

a l l i n t e r n a l l y generated heat must be dissipated t o t h e f u e l solution, t h e inner w a l l surface temperature would be about 119J°F, or 1 6 ' ~ above the bulk f l u i d temperature of ll77OF.

The outside surface of

t h e lower head a t a point 4 in. from the centerline would be about 14'F

h o t t e r than t h e inside surface and would be at 1207OF.

The

highest temperature associated with t h e cap over the drain l i n e i n t h e lower head would be about 1202'F, of t h e surrounding s a l t .

or 25OF above t h e temperature

A l l t h e estimated values mentioned above

assume no deposition of s o l i d s on t h e lower head. If s o l i d p a r t i c l e s of Zr02 were fornied i n the MSRE by oxidation

of the f u e l s a l t , these p a r t i c l e s would probably s e t t l e on t h e lower head.

T h e presence of t h i s sludge would increase t h e temperature of

t h e w a l l of t h e lower head by increasing t h e heat source a t t h e

w a l l and a l s o by reducing t h e heat t r a n s f e r c o e f f i c i e n t from t h e 2 and a w a l l t o t h e salt. I f a t h e r m h conductivity of 2 Btu/hr-ft

porosity of 30$, are assumed f o r t h e Zr02 sludge, t h e heat generation r a t e i s estimated t o be about 40,620 Btu/hr-ft 3

, of which go$ may be

due t o gamma heating and t h e remainder due t o f i s s i o n i n g i n t h e f u e l i n t h e sludge voids.

I f t h e sludge accumulation were 0.1 in. thick,

t h e added temperature difference between t h e w a l l and t h e s a l t would be about 2loF, giving a temperature of l228OF on t h e outside surface.

If t h e sludge were 0.5 in. thick, t h e difference would be about 120°F (see Ref. 18, Part 11, p 19)

Thermocouples are i n s t a l l e d on

t h e lower head of t h e v e s s e l t o a s s i s t i n detecting the accumulation

of s o l i d s and t o provide assurance that t h e temperature of t h e head

does not exceed t h e design temperature of 1300°F f o r long periods. The behavior of s o l i d p a r t i c l e s on t h e lower head was studied by introducing i r o n f i l i n g s i n t o t h e c i r c u l a t i n g stream i n t h e f u l l scale model.

After c i r c u l a t i o n f o r several hours, t h e core was

drained and t h e placement of t h e sediment i n t h e bottom head w a s examined.

Fine p a r t i c l e s appeared t o have been swept out by t h e

draining f l u i d .

Larger p a r t i c l e s accumulated near t h e drain l i n e

opening, but t h e r e were no indications of a tendency f o r t h e opening 40 t o plug, and t h e design appeared t o be adequate i n t h i s respect.

5.3.3.7

Core.

c 4

The 1/2-in.-thick INOR-8 g r i d p l a t e s that support

t h e graphite core, as shown i n Fig.

5.3 and described i n Section 5.3.1,

a r e exposed t o t h e flow of s a l t on both s i d e s .

The average v e l o c i t y

of t h e salt a t t h e g r i d i s estimated t o be about 0.16 f p s , t h e Reynolds number i s 1400, and t h e heat t r a n s f e r c o e f f i c i e n t i s @200 Btu/hr-ft2-”F.

1.7 w/cc i n t h e l i q u i d , t h e temperature difference between t h e surface of t h e INOR-8 and t h e c i r c u l a t i n g s a l t i s estimated t o be about 17V (Chapt. 11, Ref .I8).

With an assumed heat generation r a t e of

The s a l t flows i n a tortuous path through t h e graphite l a t t i c e above t h e INOR grid, and t h e pressure drop through t h e l a t t i c e i s g r e a t e r than t h e pressure l o s s through t h e core passage.

Since t h e r e s t r i c t i o n c

due t o t h e l a t t i c e blocks i s absent a t t h e f i v e s t r i n g e r positions a t t h e center of t h e core, t h e v e l o c i t i e s through t h e c e n t r a l passages a r e about t h r e e times higher than the average core v e l o c i t i e s . The flow r a t e through a t y p i c a l core passage i s roughly 1 gpm, w i t h about 2 6 more flowing through t h e passages toward t h e center

than those near t h e periphery of t h e core.

The v a r i a t i o n of t h e

flow r a t e with distance from t h e center of t h e core, as shown graphica l l y i n Fig. 5.12,

i s due t o t h e pressure gradient i n t h e lower head. 39

The point s c a t t e r on t h i s graph i s l a r g e l y d u e - t a t h e g r e a t e r tolerances i n t h e model than e x i s t i n t h e a c t i v e core. I

Flow s t u d i e s made on t h e fuel-scale model showed that t h e flow through t h e north-south f u e l passages was about 1 6 l e s s than that through t h e east-west passages because t h e upper l a t t i c e blocks s l i g h t l y obstructed t h e entrance.

To equalize t h e flow d i s t r i b u t i o n , 0.104-in.-

UNCLASSIFIED OANL- LR DWG 78808

Figure 5.12.

Flaw Distribution i n Reactor Core Fuel Passages at Total Flat Rate of 1200 gpm in Full-scale Model.

100 diam holes were bored i n t h e t o p l a y e r of l a t t i c e blocks under each

north-south flow passage.41

These holes w i l l bring t h e two banks

of points, shown i n Fig. 5.12, much c l o s e r together. The temperature d i s t r i b u t i o n i n t h e graphite and i n t h e f u e l

salt within t h e reactor core i s a function of t h e heat production r a t e and the heat t r a n s f e r .

Heat production follows t h e o v e r a l l

shape of t h e neutron flux, which i s discussed i n d e t a i l i n P a r t 111. The heat t r a n s f e r i s a function of t h e v e l o c i t i e s , which were determined

l a r g e l y through t h e model s t u d i e s . Bulk mean temperatures were obtained by i n t e g r a t i n g t h e l o c a l temperatures over t h e core volume,

These bulk temperatures a r e use-

f u l i n estimating t h e mean density of t h e f u e l and graphite t o a r r i v e a t t h e inventory of f u e l i n t h e core.

Nuclear mean temperatures

consider t h e l o c a l nuclear importances as well as t h e temperatures. Overall f u e l and graphite temperatures were calculated f o r a core that was divided r a d i a l l y and a x i a l l y i n t o regions having s i m i l a r hydraulic or nuclear c h a r a c t e r i s t i c s , giving a t o t a l of twenty regions.

A t t h e design power l e v e l of 10 Mw, with t h e r e a c t o r

i n l e t a t 1175°F and t h e o u t l e t a t l22!5OF, t h e nuclear mean temperat u r e of the f u e l w a s 1211’F and t h e graphite w a s l255’F.

The

bulk mean f u e l temperature, including a l l f u e l i n the r e a c t o r vessel except t h a t i n t h e flow d i s t r i b u t o r , w a s IlggOF, and t h e bulk mean temperature of t h e graphite w a s 122g°F, assuming no s a l t were absorbed i n it. With 0.5$ f u e l permeation, t h e nuclear mean

temperature of t h e graphite w a s 1258O~and t h e bulk mean temperature w a s l227OF.

The c e n t r a l portion of t h e core, which i s defined as

that portion inside t h e core can and between t h e bottom of t h e

lower l a y e r of l a t t i c e blocks t o t h e t o p of t h e uniform f u e l passages through the core, produces about 8746 of t h e t o t a l power.

Peripheral

regions, where t h e f u e l t o graphite r a t i o i s much higher, such as a t t h e t o p of t h e graphite matrix, account f o r t h e remaining 1%. 31 A summary of t h e nuclear data f o r t h e reactor i s shown i n

Table 5.4.

Values a r e given f o r t h r e e kinds of f u e l s a l t :

(1) f u l l y

enriched uranium with thorium, (2) f u l l y enriched uranium, and (3) p a r t i a l l y enriched uranium.

Thorium-containing salts are of i n t e r e s t

6.’

101

Table 5.4.

Suarmary of Reactor Physics Data

Core Parameters Nw~inalcore dimensions Mameter, in. H e i g h t , in. Fuel volume A. tion Y Fuel volume, ft Graphite volume, ft3 Effective core dimensions (based on extrapolation of thermal neutron flw) Dismeter, in. Eelght, in. Effective delayed neutron fractions Static Circulating Fuel type:a I n i t i a l c r i t i c a l concentration 235~,mole % U, mole $ b Operating concentration 235~,mole U, mole $ Tanperature coefficient of reactivity, OF-^ x 10-5 Fuel Graphite Totsl

55-1/4 64 0.224 20

59 78

0.0067 0 .my3 Th-235,

93% 235,

35% 235u

0.291 0.313

0.176 0.189

0.291 0.831

0 337 0.562

0.1% 0.2l.4

0.346 0.890

3 -03

-4.97 -4.91 3.47

-3.28 -3.68 -6 .% 2.40

5.7 2.5 2.29

3.4 1.5 2.32

-3.36

-6.39 neutron lifetime, sec x IO& 2.29 Thermal neutron flux n/& Sec x lolf Peak 3.4 Average 1-5 2.32 Peak/mera@;e power density, w/cc Peak 31 Average (EO ft3 of fuel)a 14 Graphite power density, w/cc 0.98 Peak Average (70 ft3 of graphite)c 0.34 Gamma heating of INOR-8, w/cc Control rod thimble at midplane 2.5 0.2 Core can, midplane Reactor vessel, midplane 0.2 Upper head at vessel outlet 0.12 Fast neutron exposure, mrt per 10 Mwyr: Reactor vessel midplane Reactor vessel upper head at outlet Reactor vessel lower head at centerline

9.88

L ‘r

Control Rod Constants F U s ~ a t typea ’

- 10 M ~ v

5 10~9 5 1019 1.3 x 1019

93%235u

Control rod worth, $ &/k

W ”

One rod Two rods Three rods

3.1 5.5 7.4

102 Table 5.4.

(Continued)

Fuel salt type8

MSX. rate of withdrawal (one rod at a time at 0.5 in./sec) $ (&/k)/sec Rate of insertion (simultaneous insertion of 3 rods a t 0.5 in./sec) $ (&/k)/sec Actuation

Th-2gyuana 35%

93% 235u

0.04

0.og

0.10

one of three rods on servo; the remaining two on manual switches

Length of rod travel, in.

Poison elements:

Poison Poison density, p / c c Ceramic cyunder (3 per element), in. Element cladding Rement dimensions, in. mer elements per rod Length of poison section, i n . Weight -3 per rod, kg Rod a t t e e n t Rod drive Drive motor Power generation in rod (max), w Cooling

O.&-ID x 1.08 OD x 0.4383 long 0.020-in. thick Inconel 0.790 ID x 1.140 OD x 1.562 long

59.36 1.2 Megnetic release Flexible hose Instantly reversible, single # 2725 C e l l atmosphere,

forced convection

Fuel Loop Parmeters

Volumes and residence times ( a t 1200"F, 1200 gp): Cored Upper head Reactor vessel t o pump Pwnp bowl Main stream Outside main stream Pump t o heat exchanger Heat exchanger Heat exchanger t o reactor vessel Vessel inlet (nozzle, volute and downcooler) Lower head Total System fuel inventory volume fuel saltf, ft3 at -OF Weights of uranium f o r fiel-salt typesa: Uranium, initial critical, kg " operating, kg 2354 initial critical, kg " operating, kg

a. b.

See Table 2.1 for fuel canposition. Allowing for -4% A k b in rods, poisons, etc. Assumes 1.4 Mw of heat generated outside of ncuninal core.

v, f t 3

Time, sec

25 -0 m.5 2.1

9.4 3.9 0.8

0-9

0.3

3.2 0.8 6.1 2.2 9.7

0.3 2.3 0.8 3.6

10.o

3.8

7 0 ~ 5 ~

25.2

85 98 79 91

52 59

218

233

Between horizontal planes a t extreme top and bottau of graphite.

contraction for One full-pwer has been calculated t o be 0.3 f t 3 (Ref 43). f . Includes fuel loop, drain line, and drain tank heel. e.

Graphite

103 i n f u t u r e large-scale breeder reactors.

The salt w i t h t h e high en-

richment of 235U i s representative of the core f u e l f o r a two-region breeder reactor.

A higher concentration of uranium was used i n t h e

t h i r d salt t o give increased tolerance f o r f l u o r i d e loss.

This was

accomplished through use of p a r t i a l l y enriched uranium and a r e l a t i v e l y l a r g e amount of 23$.

The t h i r d salt w i l l be used i n i n i t i a l oper-

a t i o n s o r t h e E R E (see P a r t I V f o r d e t a i l e d discussion of t h e chemi s t r y of t h e f u e l s a l t ) . The difference between t h e mean f u e l temperature and t h e temperat u r e of t h e center of t h e graphite i s the sum of t h e differences between t h e center and edge of t h e f u e l including t h e Poppendiek e f f e c t , 35 and t h e temperature difference i n t h e graphite caused by i t s own i n -

ternal heat generation.

These values have been calculated and t h e

maximum graphite temperature i n t h e reactor i s estimated t o be 1296O~

a t r a t e d flow and power,

This maximum occurs about 50 i n . from t h e

bottom of t h e &-in.-high

core matrix and about 7 i n . from t h e center-

l i n e . 31 The average f u e l residence time i n t h e core i s 7.5 sec, and t h e average f u e l - s a l t temperature increase as it passes through t h e core

i s about 50°F a t 10 Mw of reactor power and with a flow r a t e of 1200

gpm, providing nominal temperatures f o r t h e entering salt of 1175OF and f o r t h e leaving s a l t of l225OF. It i s calculated t h a t t h e f u e l s a l t leaves t h e h o t t e s t flow channel through t h e core a t about

1262OF 31

5.3.3.8

Upper Head.

On leaving t h e r e a c t o r core, t h e f u e l

salt passes i n t o t h e r e a c t o r vessel upper head.

Flow i n t h e head

w a s observed i n t h e models t o be turbulent and t h e heat t r a n s f e r more than adequate; therefore, f e w d e t a i l e d s t u d i e s were made of t h i s region of t h e r e a c t o r vessel. The region j u s t above t h e core-can flange, described i n Section

5.3.1, w a s given some study. Although more than 24 gpm i s introduced i n t o t h e region through s l o t s and clearances, estimates of temperature

were made on t h e b a s i s t h a t t h e s l o t s were plugged. The method of heat transport was considered t o be t r a n s f e r down t h e pressure vessel w a l l and through the core-can flange t o t h e wall-cooling annulus, and radial

104 t r a n s p o r t of t h e heat t o t h e f u e l i n t h e gap between t h e core can and t h e graphite core.

It was assumed that t h e reactor w a s insulated and

that gamma heatinq i n t h e metal walls was 0.1 w/cc.

bi ’..

With these

assumptions, t h e temperature was calculated t o be about 30°F above t h e r e a c t o r i n l e t temperature of 1175°F and occurred a t a point about

3 i n . above t h e flow d i s t r i b u t o r .

With t h e f l o w - r e s t r i c t o r r i n g

gap plugged so that no salt flowed upward between t h e graphite core and t h e core can, t h e temperature a t t h e same point was estimated t o be about 40OF above t h e r e a c t o r i n l e t temperature.

The upper head a l s o contains t h e discharge s t r a i n e r assembly, which w i l l be described subsequently.

5.3.4

Reactor Access Nozzle, Plug, and S t r a i n e r The 10-in. nozzle through which t h e s a l t leaves t h e upper head

of t h e reactor vessel has a kO-in.-long extension welded above it. This extension has a 5-in. s i d e o u t l e t f o r t h e leaving salt.

The

extension serves as a housing f o r t h e nozzle plug, which i s a removable support f o r the t h r e e 2-in. control rod thimbles, t h e 2-1/2-in. graphite sample access pipe, and f o r t h e discharge screen, as shown i n Fig. 5.4. Thermal s t r e s s e s induced by t h e temperature gradient across t h e nozzle extension w a l l were investigated and found t o be well within t h e allowable limits.

The removable nozzle plug i s about 20-1/2 i n . long and i s 9.770 i n . OD a t t h e t o p and 9.520 i n . OD a t t h e bottom t o provide a t a p e r t o assist i n f r e e i n g the plug f o r removal.

The r a d i a l clearance i s

1/8 i n . a t t h e t o p and 1/4 i n . a t t h e bottom.

Fuel salt i s frozen

i n the annular space between t h e plug and t h e nozzle, t o e f f e c t a

salt s e a l .

The salt i s maintained below t h e freezing temperature

by cooling t h e outside of t h e nozzle extension and t h e i n s i d e of t h e plug with a flow of c e l l atmosphere gas.

About 10 cfm of t h i s g a s

i s supplied t o t h e outside of the nozzle extension and t h e i n s i d e of’the plug with a flow of c e l l atmosphere g a s .

About 10 cfm of t h i s gas

i s supplied t o t h e outside cooling jacket through a 1/2-in. pipe, l i n e 962, and about 10 cfm i s supplied through l i n e 963 t o t h e inner cooling jacket.

The discharge of both jackets i s t o t h e c e l l atmos-

105

phere.

The salt s e a l prevents t h e s a l t from coming i n contact with

and corroding t h e ring-joint gas seal on t h e upper flange. The nozzle plug i s hollow and i s f i l l e d w i t h i n s u l a t i o n .

The

upper end of t h e plug i s welded t o t h e mating flange f o r t h e 10-in. closure.

This flange i s provided with an O-ring s e a l t o make t h e

j o i n t gas t i g h t .

The b o l t i n g f o r t h e flange i s arranged f o r manipu-

l a t i o n with remotely operated tooling.

It may be noted that when t h e

flange i s unbolted, t h e plug can be withdrawn, carr33ng t h e control

* %

rod thimbles, t h e graphite-sample guide tube, and t h e discharge screen assembly w i t h it. The upper head of t h e reactor vessel has an 18-in.-diam s t r a i n e r

r i n g mounted just below t h e discharge nozzle opening, as shown i n

Fig.

5.4.

This r i n g i s welded t o s i x equally spaced lugs and t o a

strengthening ring.

The s t r a i n e r i s f a b r i c a t e d of 16-gage INOR-8

p l a t e with staggered 3/32-in. -diam holes on 9/64-in. centers, and

w i l l s t o p l a r g e graphite chips.

The center of t h e s t r a i n e r r i n g i s

cut away t o permit t h e 9.52-in.-OD

strainer-basket assembly on t h e

nozzle plug t o pass through it. An INOR-8s e a l ring, 1/4 i n . by 3/4 i n . wide, 9583 i n . I D and 11.083 i n . OD, i s loosely mounted with t h e s t r a i n e r r i n g and makes a n acceptably close f i t with t h e s t r a i n e r basket. The lower end of t h e nozzle plug i s contoured t o d i r e c t t h e f u e l salt stream toward t h e 5-in. s i d e o u t l e t . t 7

Projecting below

t h i s i s a 9.520-in. -dim by 12-17/32-in. -long cylinder of 1/8-in.

t h i c k p l a t e f o r supporting t h e s t r a i n e r basket.

The basket is

welded t o t h e bottom of t h e cylinder, i s 9.520 i n . OD a t t h e t o p c

and about 8-1/2-in.

OD a t t h e bottom and i s about 7 i n . deep.

The

holes i n t h e basket s t r a i n e r a r e of t h e same s i z e and configuration

as those i n t h e s t r a i n e r ring, mentioned above.

The t h r e e IN OR-^-

graphite sampler baskets, described previously i n Section 5.3.1, through a 2-3/8 i n . d i m opening i n t h e s t r a i n e r basket.

pass

The t h r e e

2-in.-diam control rod thimbles a l s o pass through t h e s t r a i n e r basket. A cross-shaped extension of t h e basket assembly projects beneath t h e

basket about 2-1/2 i n . to act as a hold-down f o r t h e f i v e f u l l - s i z e d *

graphite s t r i n g e r samples a t t h e center of t h e r e a c t o r core.

106 A l l clearances between t h e s t r a i n e r basket and t h e s t r a i n e r ring,

6, c

thimbles, e t c . , a r e l e s s than 1/16 i n . s o t h a t graphite chips w i l l be retained.

5.3.5

Control Rods

5.3.5.1

Introduction.

Excess r e a c t i v i t y must be provided over

that required f o r t h e reactor t o be c r i t i c a l while clean and noncircu-

l a t i n g a t 12OOV, i n order t o compensate f o r xenon poisoning, loss of delayed neutrons f r o m t h e reactor via t h e leaving f u e l salt, t h e negative power coefficient, and f o r some burnup i n t h e f u e l .

Variations

i n t h e pump speed and possible differences i n t h e degree of f u e l pene-

- 1

t r a t i o n i n t o t h e graphite may a l s o require some shim control of reac-

tivity.

It i s a l s o desirable t o hold t h e reactor s u b c r i t i c a l during

s t a r t u p operations when charging f u e l salt i n t o t h e system by procedures other than heating t h e system t o high temperatures.

The

adjustment of r e a c t i v i t y i s provided f o r i n t h e MSRE by t h r e e i d e n t i c a l control rods located near t h e center of t h e MSRE core. While control rods are employed f o r the above-mentioned reasons, t h e nuclear s a f e t y of t h e reactor i s not primarily dependent upon them.

The rods a r e , therefore, not a f a s t - a c t i n g type, designed f o r

extreme r e l i a b i l i t y .

Simultaneous withdrawal of a l l t h r e e rods would,

however, c r e a t e an undesirable s i t u a t i o n under c e r t a i n conditions, necessitating c e r t a i n interlocks and controls.

The control philosophy

i s covered i n P a r t 11.

The need f o r a graphite-sampling arrangement a t t h e center of t h e reactor complicated design of t h e control rod system i n that it w a s a l s o necessary that t h e control rods be i n a region of high nuclear importance.

The graphite-sampling equipment i n t e r f e r e d dimensionally

with t h e use of s t r a i g h t control rods and d i c t a t e d that t h e rods be f l e x i b l e and used i n thimbles having

o f f s e t t i n g bends.

This type of

rod was used successfully i n t h e A i r c r a f t Reactor Experiment. 10 Early plans f o r use of natural boron carbide ( 1 9 B ) as t h e poison material were abandoned i n favor of gadolinium oxide i n that t h e l a t t e r increased t h e control rod worth as well as eliminated t h e problem associated with t h e boron of helium pressure buildup i n t h e sealed cans containing t h e poison.

The s e l e c t i o n of t h e control rod

poison material i s discussed i n detail i n P a r t 111.

107 7

5.3.5.2

Description.

Three control rod thimbles a r e arranged

equidistant from t h e center of t h e core matrix a t t h e graphite s t r i n g e r locations shown i n Fig. 5.7. The centers of t h e control rods a r e 2-53/64 i n . from the reactor c e n t e r l i n e . The thimbles a r e f a b r i c a t e d of 2-in. sched-40 INOR-8pipe t h a t

i s reduced t o 2-in.-OD by 0.065-in. w a l l tubing i n t h e bottom 5 f t of length that i s i n s e r t e d i n the graphite core. They a r e supported

by t h e removable plug i n t h e reactor access nozzle, and have two 16-in.-radius 3-" o f f s e t t i n g bends j u s t above t h e nozzle extension closure flange t o permit t h e control rods t o c l e a r t h e graphitesampler equipment. The thimbles extend through t h e core matrix t o about 1/2 i n . above t h e graphite l a t t i c e blocks.

Four INOR-8spacer

sleeves, about 1-1/2 i n . long and with eight f i n s , a r e welded t o each thimble t o position it equidistant from adjoining graphite s t r i n g e r s , as indicated i n Fig. 5.4 (see ORNL Dwg. E-BB-B-40598). The control rods a r e segmented t o provide t h e f l e x i b i l i t y needed t o pass through t h e bends i n t h e control rod thimbles.

The

poison material i s i n t h e form of thin-walled cylinders, as shown i n F i g . 5.13.

The ceramic cylinder i s a mixture of 70 w t $ gadolinium

oxide and 30 wt $ aluminum oxide, 1.08 i n . OD x 0.84 i n . I D x 0.438 i n . long. Three cylinders a r e canned i n a 0.020-in.-thick welded Inconel s h e l l 1.140 i n . OD x 0.790 i n . I D x 1.562 i n . long (see ORNL Dwg. E-BB-B-56347 and ORNL Specification JS-81-183). The properties and f a b r i c a t i o n requirements of t h e poison elements a r e discussed i n Part IV. Thirty-eight elements a r e used f o r each control rod, providing

i -

a poison s e c t i o n 59.4 i n . long.

A s indicated i n Fig. 5.14, t h e

segments a r e threaded, bead-like, on a 3/4-in.-OD by 5/8-in.-ID h e l i c a l l y wound, f l e x i b l e s t a i n l e s s s t e e l . Two 1/8-in. -diam braided Inconel cables run through t h i s hose t o r e s t r a i n it from s t r e t c h i n g when dropped i n f r e e f a l l a t operating temperature of 1200-1400°F. A t t h e t o p of t h e poison section a r e t a i n e r r i n g holds t h e elements

i n place and an adapter changes t h e hose t o a s t a i n l e s s s t e e l convoluted type with a s i n g l e wire-mesh sheath.

-U

This hose passes upward

through t h e thimble t o t h e positioning chain on t h e control-rod drive

108

. Unclassified ORNL DUG 64-8816

.. I

POISON MATERIAL0% Gd2O3

1.08'' O.D.. 0.84" 1.D)

-B

_- I 'SEAL

RING

INCONEL SHELL I

SECTION "A-A"

Fig. 5.13. Control Rod Poison Element.

109 UNCLASSIFIED

ORNL-LR-DWG 67511

REVERSIBLE DRIVE M O T O R 7 COOLANT TO DRIVE

SOLENOID ACTUATED RELEASE

MECHANICAL CLUTCH GEAR AND ARM FIXED DRIVE SUPPORT AND 3in. CONTAINMENT TUBE

SPRING LOADED ANTIBACKLASH HEAD AND IDLER GEAR

16 in. RADIUS x 30° BEND

COOLANT EXHAUST

GUIDE BARS, 4 AT SOo

BEADED POISON ELEME

2in CONTAINMENT THIMBL

Fig. 5.14. Control Rod and Drive Assembly

110 The t o t a l length of a control rod assembly from t h e bottom

mechanism.

of t h e poison elements t o t h e drive chain connector i s about 14 f t . See ORNL Dwg. E-BB-B-56334. Each control rod i s provided w i t h an individual rod drive mechani s m housed i n a box located adjacent t o t h e graphite-sampler stand-

pipe. The drive mechanism i s accessible using remote t o o l i n g operated through t h e standpipe workshield (see Section 5.3.6)

Each rod i s moved by a l/3O-hp servo-motor driving through a brake, gear reducer, clutches, and a sprocket chain, as shown diagrammatically i n Fig. 5.15.

Two small synchros, driven from a bevel

gear on the main sprocket drive shaft, i n d i c a t e rod motion, one a t

5" per inch of movement and t h e other a t 60" per inch of movement. A l i n e a r potentiometer i s a l s o actuated by t h e drive shaft t o pro-

vide a position signal which i s used i n t h e s a f e t y c i r c u i t s .

The

method of c a l i b r a t i o n of those instruments w i l l be discussed subsequently. The control rod drive i s self-locking i n that, w i t h t h e magnetic clutch engaged and t h e drive motor exerting no torque, t h e rods w i l l not descend by t h e i r own weight (6 t o 8 l b ) .

An over-running clutch

provides a positive drive connection between t h e motor and t h e chain sprocket t o assure rod i n s e r t i o n .

When t h e electromagnetic c l u t c h

i s disengaged, t h e over-running c l u t c h a l s o allows t h e rod t o f a l l

freely.

The drive u n i t i s capable of exerting a downward t h r u s t of

about 20 l b , and an upward p u l l of roughly 25 l b . i s 60 i n . a t a maximum speed of 0.5 in./sec.

The direction of movement

of t h e rods can be reversed i n less than 0.5 sec. stopped i n less than 0.25 sec.

The t o t a l stroke

Motion can be

The clutch release time i s not more

than 0.05 sec, and t h e rod acceleration during a scram i s a t l e a s t 2 L i m i t switches a r e provided a t each end of the stroke. 12 f t / s e c

The drive u n i t s were designed t o operate i n a r a d i a t i o n f i e l d of 105 rad/hr.

The bearings a r e of t h e nonlubricated type and t h e

u n i t i s arranged f o r remote maintenance, o r replacement, by t o o l i n g operated from above.

The control rod drives were designed and f a b r i -

cated by t h e Vard Corporation (Pasadena, Calif .) Specification JS-80-144)

. (See ORNL

. 111

UNCLASSIFIED ORNL-LR-DWG 78806

SYNCHRO N0.2

60° PER INCH OF ROD MOTION

POTENTIOMETER GEAR REDUCER NO. 2 INPUT SPROCKET

GEAR REDUCER NO. 1

SPROCKET CHAIN

OVERRUNNING CLUTCH

FLEXIBLE

TUBULAR ROD SUPPORT^

1;l

REACTOR VESSEL CELL I

POISON ELEMENTS

POSITION INDICATOR AIR FLOW RESTRICTOR AIR DISCHARGE - RADIAL PORTS

Fig. 5.15. Diagram of Control Rod Drive.

112 The control rods a r e heated p r i n c i p a l l y by t h e absorption of f i s s i o n capture and fission-product decay gamma rays and t h e absorpt i o n of r e c o i l k i n e t i c energy of t h e products of reaction.45

The

poison elements a r e cooled by 1 5 scfm of c e l l atmosphere gas (954 N2,

5% 0 2 ) supplied a t 150°F through l i n e 915 t o t h e f l e x i b l e positioning hose of each rod c35 scfm per rod), t h e gas returning upwards around t h e canned poison sections t o be exhausted t o t h e reactor containment c e l l atmosphere.

The gas discharge temperature i s estimated t o be

about l l O O o F and t h e poison elements may operate a t a maximum temperat u r e of about 1350oF.

Complete l o s s of cooling a i r with t h e reactor

at f u l l power would cause t h e maximum temperature i n t h e control rod t o r i s e t o about l 5 O O o F . A positive-position i n d i c a t o r i s provided f o r t h e lower end of

t h e rod which permits r e c a l i b r a t i o n of t h e position-indicating devices, which a r e r e l a t e d t o t h e upper end of t h e rod, should t h e r e be variations i n t h e length.

The accuracy of rod position indication

needed f o r s a f e reactor operation w a s established as k0.2 i n .

Development t e s t s indicated that variations i n length g r e a t e r than t h i s could be expected when dropping t h e rods i n simulated scram conditions a t operating temperatures.

P o s i t i v e indication of position

of t h e lower end i s provided by t h e cooling gas flow down t h e center of t h e f l e x i b l e hose.

A nozzle with r a d i a l ports i s attached t o t h e

bottom end and a r e s t r i c t o r , o r t h r o a t , i s welded t o t h e guide bar cage a t a known point near t h e bottom of t h e thimble.

When t h e nozzle

passes through t h e t h r o a t , t h e change i n pressure drop i n t h e gas flow through t h e rod assembly i s r e a d i l y apparent and gives a position indication t o within l e s s than 0.1 i n . t h e position-indicating instruments can be c a l i b r a t e d against t h i s known p o s i t i o n of t h e lower end of t h e rod.

5.3.5.3

(See Figure 2.2, P 49, Ref

Control Rod Worth.

122. )

Each of t h e t h r e e rods, when f u l l y

i n s e r t e d and t h e other two completely withdrawn, has a worth of 2.w Ak/k.*

When a l l t h r e e rods are completely inserted, t h e t o t a l

worth i s 6.B Ak/k.*

A t t h e maximum withdrawal r a t e of 0.5 in./sec,

normally limited t o one rod a t a time, t h e change i n r e a c t i v i t y i s

O.Ok$ (Ak/k)/sec.*

Simultaneous i n s e r t i o n of a l l t h r e e rods a t a

113 r a t e of 0.5 in./sec causes a change i n r e a c t i v i t y of O.O$

(Ak/k)/sec.*

These and other control rod constants a r e summarized i n Table 5.4.

A discussion of t h e nuclear aspects of the rods i s given i n P a r t 111. Instrumentation i s described i n P a r t 11.

5.3.6

Graphite Sampler One of t h e objectives of t h e MSRE i s t o i n v e s t i g a t e t h e behavior

of t h e unclad graphite moderator i n t h e r e a c t o r environment.

Thus,

t h e reactor w a s designed f o r periodic removal of graphite specimens from near t h e center of t h e core.

The samples a r e exposed t o much

t h e same salt velocity, temperature, and nuclear f l u x as t h e graphite s t r i n g e r s which make up t h e core matrix.

The specimens can be w i t h -

drawn only when t h e reactor i s inoperative and t h e f u e l s a l t i s drained from t h e primary c i r c u l a t i n g system.

When a sample i s removed f o r

analysis, it must be replaced by another sample i n order t o maintain t h e same flow p a t t e r n through t h e core. The t h r e e graphite sample baskets mounted v e r t i c a l l y within a s t r i n g e r p o s i t i o n and t h e f i v e removable s t r i n g e r s a t t h e center of t h e core have been described i n Section 5.3.1.

The small baskets

can be removed o r replaced more o r l e s s routinely through t h e sample access nozzle ( t o be described subsequently),

Access t o t h e f i v e

s t r i n g e r s i s obtained through removal of t h e e n t i r e reactor-vesselaccess-nozzle plug assembly.

While t h i s i s accomplished through a

s p e c i a l work s h i e l d provided f o r t h e purpose, it i s not a routine procedure.

A s shown i n Figs. 5.4, t h e graphite-sample access plug f i t s i n t o c

t h e sample access nozzle.

The INOR-8plug i s 1.610 i n . I D x 2.375

i n . OD x 46-13/32 i n . long and terminates a t t h e t o p i n a 7-in. flange. The flange i s f i t t e d with a bin.-diam O-ring closure.

The bottom of

t h e plug i s contoured t o help d i r e c t t h e flow of f u e l s a l t t o t h e s i d e o u t l e t of t h e 10-in. reactor-vessel nozzle.

The plug i s cooled

by c e l l atmosphere gas (954 N2, 546 0 ) introduced a t t h e center 2 through a 1/2-in. sched-40 s t a i n l e s s s t e e l pipe (see Fig. 5.4 ) .

*For thorium-containing and p a r t i a l l y enriched f u e l s a l t . control rod data with highly enriched f u e l , see Table 5.4.

(This

For

-. 114

cooling tube has a two-bolt flange at the top to permit it to be withdrawn fromthe graphite sample access nozzle during maintenance or sampling procedures and temporarily replaced with a metal-sheathed heater of the "Firerod" type. This arrangement assures melting of any residual salt to permit withdrawal of the sample access nozzle and its attached hold-down rod and cup.) The cooling-gas flow is adjusted during reactor operation to freeze fuel salt in the 1/8- to 1/4-in. tapered annulus between the plug and the nozzle to obtain a seal. The O-ring closure is buffered and leak-detected with helium. The INOR-8 graphite-sample access nozzle is 2.421 in. ID x 2.875 in.

OD x 39-17/32 in. long, and is welded to the closure for the 10-in. reactor-vessel access nozzle, as shown in Fig. 5.4. A flange at the upper end bolts to the mating flange on the sample access plug with an O-ring joint (previously mentioned) and also bolts to the graphitesampler standpipe. The standpipe connections is through a 10-in.-diam by 8-in.-long stainless steel bellows, which permits relative movement of the standpipe and the reactor vessel. Two different graphite-sampler standpipes are available for joining the reactor access nozzle to the opening in the reactor-containment roof plug. The one left in place, and designated "No. 1," is used when taking one of the small graphite-sample assemblies. Standpipe

No. 2, which will be described subsequently, is used when removing and replacing the 2 by 2-in. graphite stringers. Standpipe No. 1 is fabricated of stainless steel and is 19-3.4 in. ID x 20 in. OD x 8 ft 10-1/8in. high. A l l joints and connections are gas-tight, and the standpipe is provided with purge and off-gas connections. A s indicated in Figs. 5.4, 5.5, and 5.16 the upper end of the standpipe is bolted to a 40-in.-dim stainless steel liner set into the lower magnetite concrete roof plug. The lower end of the standpipe is fitted with the bellows extension which is bolted to the graphitesample access nozzle. During nonnal power operation the liner opening is closed with a magnetite-concrete plug 35-1/2 in. thick, 41-1/2in. OD, and weighing about 6000 lb. A 6-in.-diam inspection port in this plug can be opened by removing a stainless-steel-canned magnetite-concrete plug,

. *

aZim-cg ssaoqf

Mgure 5.16.

of specimen Assenibly.

Schematic of Reactor Access Shawn Ready for Removal

, ++ C'

116 which i s 35-1/2 i n . long, and i n s e r t i n g a lead-glass plug.

The 3-1/2-

f t - t h i c k ordinary concrete shield block, or roof plug, would cover these openings during reactor operation. When taking a graphite sample, w i t h the reactor shut down and drained of f u e l salt, t h e upper shield block i s taken away, t h e magn e t i t e concrete plug i s removed from t h e t o p of t h e l i n e r , and a 3-fthigh working s h i e l d i s i n s t a l l e d by placing it on t h e lower shield block above t h e opening. This working shield (see Fig. 5.17) has w a l l s of 4-in.-thick lead, i s canned i n s t a i n l e s s s t e e l , and weighs

about 8250 l b .

A gas-tight s e a l i s made by i t s weight bearing on two c

Teflon O-ring s e a l s on the bottom periphery (see ORNL Dwg. D-BB-C40657). A work plug inserted i n the t o p of t h e working shield i s 12 i n . t h i c k and contains a 3-in.-diam,

heavy plate-glass viewing port,

t o o l openings, illuminating l i g h t , and purge and off-gas connections. The work plug s i t s on Teflon gaskets t o make a gas-tight seal. The plug can be rotated by a gear and pinion arrangement (see ORNL Dwg. E-BB-C-40646). The 4O-in.-diam l i n e r i n t h e lower roof plug and the 2O-in.-diam graphite-sampler standpipe No. 1 a r e not concentric but have circumferences which a r e almost tangent.

The crescent-shaped opening thus

provided t o one side of the standpipe gives access t o t h e control-roddrive mechanisms.

Maintenance of t h i s equipment can be accomplished through the work shield. The shield can a l s o be used t o c l e a r t h e equipment from t h e 10-in. reactor-vessel access nozzle t o remove t h e f i v e graphite s t r i n g e r s a t t h e center of t h e core o r t o view the lower head of t h e vessel.

I n b r i e f , t h e procedure f o r taking a graphite sample i s as follows. F i r s t , the upper concrete shield block i s removed and t h e bO-in.-dim concrete plug i s taken out of t h e lower s h i e l d block. The work s h i e l d i s then placed over the standpipe opening, a specimen assembly i n an unexposed sample holder with a t o p cover, an empty specimen holder with no t o p cover are placed i n t h e standpipe i n t h e wells provided. The standpipe i s then carefully purged with nitrogen o r helium gas u n t i l t h e atmosphere i s acceptable f o r entry i n t o t h e reactor c i r c u l a t i n g system.

Working w i t h remotely operated tooling through t h e work plug,

UNCLASSIFIED ORNL-DWG. 64-6745

L E A D GLASS V I E W I N G WINDOWS

A-

PLUG D R I V E GEARS

I-‘

I-‘ 4

TOOL BUSH I NG PLUG PURGE VENTS-

SH I E L D

WORK

SHIELD FOR GRAPHITE SAMPLER FIG. 5.17

” 4

118 t h e sample access plug i s unbolted from t h e sample access nozzle flange i n t h e bellows extension a t the bottom of t h e standpipe.

6-i t

The 1/2-in.

cooling-gas l i n e s a r e disconnected from t h e access plug by use of t h e quick-disconnect couplings.

The access plug, w i t h i t s attached hold-

down rod, i s then withdrawn and s e t a s i d e i n t h e rack provided i n t h e standpipe.

A s p e c i a l t o o l can then be i n s e r t e d through t h e graphite-

sample access nozzle t o t h e t o p of t h e core t o engage and withdraw one of t h e exposed graphite-sample assemblies.

This i s placed i n t h e

empty specimen holder and t h e t o p cover f r o n t t h e unexposed specimen

holder i n s t a l l e d on it. The unexposed specimen assembly i s then i n s e r t e d i n t o t h e core, and t h e access plug i s replaced.

The stand-

pipe i s purged of radioactive gases t o t h e off-gas system.

After a

s u i t a b l e decay period t h e graphite sample i s t r a n s f e r r e d t o a s p e c i a l c a r r i e r f o r t r a n s p o r t t o t h e a n a l y t i c a l laboratory i n t h e X-10 area. Should it be necessary t o remove and replace any of t h e f i v e 2 by 2-in. s t r i n g e r s from t h e center of t h e core, t h e r e a c t o r would

be shut down and drained, the upper roof block would be removed, t h e round plug i n t h e lower roof block would be l i f t e d and s e t aside, and t h e work shield, with i t s work plug, would be s e t i n place.

Stand-

pipe No. 1 would then be disconnected, which a l s o n e c e s s i t a t e s disconnection and removal of t h e control-rod-drive assemblies.

After s e t t i n g

t h e working s h i e l d aside, t h e overhead crane would be used t o l i f t

standpipe No. 1 and t o s e t standpipe No. 2 i n place.

This standpipe i s

34-1/2 i n . OD and i s f a b r i c a t e d of 11-gage s t a i n l e s s s t e e l .

The t o p

flange of t h e standpipe attaches t o t h e lower roof block i n t h e same manner as standpipe No. 1. The lower end attaches t o t h e 10-in. access nozzle flange.

Then, by working with s p e c i a l t o o l i n g through

t h e work plug, t h e plug i n t h e 10-in. access nozzle would be removed and t h e 2 by 2-in. graphite s t r i n g e r s would be withdrawn from t h e core matrix.

5.3.7 Mechanical Design of Reactor Vessel The reactor-vessel-shell and head thickness requirements were determined by t h e r u l e s of t h e ASME Unfired Pressure Vessel Code, Section V I I I . 47

-I z

119 The vessel design conditions were taken as 50 psig and 13OO?F. The allowable s t r e s s used i n t h e various computations w a s 2750 p s i . changes with temperature as shown The allowable s t r e s s f o r INOR-8 i n Fig. 5.18.

The s t r e s s values shown i n t h i s f i g u r e a r e f o r wrought

and annealed sheet, p l a t e , piping and tubing, and do not apply t o weld o r c a s t metal.

However, t e s t s have shown welds t o have properties as

good as t h e parent metal.

The allowable s t r e s s e s used i n t h e design of

t h e reactor were based on t h e lowest value obtained from any of t h e following c r i t e r i a : 53 1. One-fourth of t h e minimum specified t e n s i l e strength, adjusted

f o r temperature v a r i a t i o n .

A s shown i n Fig. 5.18 t h i s c r i t e r i o n was

c o n t r o l l i n g i n t h e 0 - 200°F range. 2.

Two-thirds of t h e minimum specified y i e l d strength, adjusted

f o r temperature v a r i a t i o n .

T h i s c r i t e r i o n established t h e allowable

s t r e s s i n t h e 200 - 9OOOF range.

3. Four-fifths of t h e s t r e s s t o produce rupture i n 100,000 h r . I n t h e temperature range of 900

- l O 3 O o F t h i s f a c t o r was controlling.

4. Two-thirds of t h e stress t o produce a creep r a t e of O.l$ i n 10,000 h r .

This c r i t e r i o n established t h e allowable s t r e s s above lO3Ov,

which i s t h e range f o r which t h e pressure vessel must be designed. The f i r s t three of t h e above c r i t e r i a correspond t o standard practices (see Ref 47, Appendix Q, p 174).

A s a f e t y f a c t o r of two-

t h i r d s w a s applied i n t h e f o u r t h c r i t e r i o n t o allow for v a r i a t i o n t

between batches of material and other u n c e r t a i n t i e s . I n 1962 t h e ASME code committees accepted INOR-8(Hastelloy N) as a material of construction f o r unfired pressure vessels.

The

allowable s t r e s s e s under t h e code exceed those used i n t h e MSRE design by about 20$. The curves of Fig. 5.18 show t h a t t h e allowable s t r e s s e s drop from 6000 p s i a t 1200°F t o 1900 p s i a t 1400OF and emphasize t h e need t o

maintain e f f e c t i v e cooling of t h e pressure-stressed portions of t h e system.

Under normal operating conditions t h e w a l l of t h e pressure

vessel i s estimated t o be no h o t t e r than 1180?1?, t h e lower head 119OOF, and t h e upper head 1230°F.

A design temperature of 1300°F was taken

i n order t o provide some additional margin.

The low allowable s t r e s s

120

Unclassified ORNL IlwG 64-8818

40 30 x)

f j 10

2 8 rl

E 6 a

g 4

c1 m

----

------ 4/5 Rupture Strength (lo5 hrs) (RS) ----- 2/3 0.1 Creep Rate U n i t (CRU) Max-

Allowable Stress

3 2

1 0

200

400

600 Temperature

Figure 5.18.

800

looQ

Criteria for Establishing Static Design Stresses in INOR-8.

1200

1400

121 of 2750 p s i used f o r design i s based on the long-term creep properties of t h e m a t e r i a l a t 1300°F, but it i s t o be noted t h a t even a t 180OoF t h e t e n s i l e strength and y i e l d strength of the m a t e r i a l are s t i l l above 30,000 and 20,000 p s i , respectively.

This implies t h a t short exposures

t o abnormally high temperatures would not produce complete f a i l u r e of t h e equipment. Estimates of t h e thicknesses of t h e material required were based on standard formulae.18 X

I n a l l cases t h e a c t u a l thicknesses used were

g r e a t e r than those calculated t o be required.

Estimates of t h e s t r e s s e s

at t h e nozzles were based on e a r l y predictions of t h e forces and moments imposed by t h e piping system.18

Since t h e calculated s t r e s s e s were

well within t h e acceptable range,53 t h e values were not revised t o correspond w i t h t h e nozzle reactions obtained by more refined analyses of t h e piping systems. The portions of the reactor pressure v e s s e l receiving s p e c i a l study were t h e upper and lower heads, t h e s h e l l , the i n l e t nozzle and f l a w d i s t r i b u t o r , and t h e o u t l e t nozzle. support b a r s were a l s o investigated.

The INOR-8core g r i d

Stresses induced by possible

thermal gradients were considered i n a l l cases. The s t r e s s e s imposed on t h e reactor support lug by t h e support 1

rod were found t o be l e s s than two-thirds of t h e y i e l d s t r e s s but higher than t h e allowable two-thirds of t h e 0.1% CRU (Creep Rate Unit).

A s a r e s u l t , it can be a n t i c i p a t e d that a small amount of creep could

occur, increasing t h e contact a r e a and r a p i d l y lowering t h e contact s t r e s s t o w i t h i n an acceptable range (see page 48, Ref. 18). The graphite l a t t i c e blocks were designed on t h e basis of bending stress estimates a t p o i n t s of maximum moment.

The calculated s t r e s s e s

were less than 100 p s i (see page 38, Ref. 18).

5.3.8

Tubes f o r Neutron Source and Special Detectors Thimbles a r e provided i n t h e thermal s h i e l d f o r a neutron source

and for two s p e c i a l neutron detectors f o r use primarily during t h e

c r i t i c a l experiments.

The inherent source of neutrons i n t h e unirradi-

ated f u e l from reactions between t h e alpha p a r t i c l e s emitted by t h e uranium, primarily 234U,

and t h e beryllium, fluorine, and lithium

nuclei w i l l be 3 t o 5 x 105 neutrons per second.

This i s adequate f o r

122

s a f e t y purposes; but a stronger source i s desirable f o r following t h e approach t o c r i t i c a l i t y , and an antimony beryllium o r polonium beryllium neutron source of about 109 neutrons per second w i l l be provided f o r t h i s purpose.

The source w i l l be i n s e r t e d i n a thimble made from a 1-1/2-in. sched-40 pipe, 9-l/2 f t long, located i n plug No. 1 i n t h e westnorthwest s e c t o r of t h e thermal s h i e l d (see ORNL Drawing E-DD-B-40726) The source pipe i s protected from damage by t h e 1-in.-diam steel balls f i l l i n g t h e thermal s h i e l d by a surrounding half-section of 8-in. sched-40 s t a i n l e s s s t e e l pipe.

The l o c a t i o n i n t h e thermal s h i e l d

was chosen because t h e temperature w i l l be low, so any standard source can be used without concern f o r i t s thermal properties.

The

source i s on t h e opposite s i d e from t h e nuclear instrument thimble and near t h e inner w a l l of the thermal s h i e l d .

The source w i l l be

placed i n a cage and w i l l be lowered o r r a i s e d by a simple arrangement of a small, braided, wire cable fastened t o t h e cage and extended t o t h e operating f l o o r l e v e l . The two tubes f o r t h e s p e c i a l neutron detectors a r e similar t o t h e source tube but are 2-in. sched-10 pipe and a r e located i n t h e northeast and southeast s e c t o r s of t h e thermal s h i e l d .

The chambers

i n these tubes are intended f o r use only during t h e c r i t i c a l experiments and t h e e a r l y power experiments. Use of t h e neutron source during s t a r t u p of t h e r e a c t o r i s d i s cussed i n d e t a i l i n P a r t I11 and P a r t VIII.

The f i s s i o n chamber

instrumentation i s described under Instrumentation, P a r t 11.

5.3.9

support The r e a c t o r vessel i s supported from t h e t o p removable cover of

t h e thermal s h i e l d by twelve hanger-rod assemblies.

As shown i n F i g .

5.19, t h e bottoms of these assemblies a r e pinned t o lugs welded t o t h e r e a c t o r vessel j u s t above the flow d i s t r i b u t o r .

The tops of t h e assemblies a r e pinned t o t h e support p l a t e s i n t h e cover. The cover

i s supported by t h e thermal shield assembly, which, i n t u r n , rests on t h e I-beams of t h e major support s t r u c t u r e i n t h e containment vessel.

5 3-11 t

The thermal s h i e l d w i l l be described subsequently i n Section

123 Unclassified ORNL DWG 64-8819

bi 5

Thenaal Shield cmer

1-1/4 i n . M a Pin

6 NC Threads (Right Hand) T-

I!d/

1-1/4 i n . Ma INOR-8 Hanger R a d s (12)

6 NC Threads I

Ill

Reactor Vessel

1-1/4 in. Ma INOR-8 Pln

Lug Welded t o

Vessel

T Figure 5.19.

Reactor Vessel Hanger Rods

124 Since t h e reactor vessel i s not accessible when i n position i n s i d e t h e thermal shield, t h e vessel w i l l be attached t o t h e thermal shield cover i n a job outside t h e r e a c t o r c e l l .

b/ I

All adjustments, attachment

of thermocouples, e t c . , including f i n a l inspection, w i l l be completed before t h e reactor and cover assembly i s lowered i n t o position.

Maint-

enance on t h e reactor, other than that which can be accomplished through t h e reactor access nozzle, requires l i f t i n g of t h e cover and t h e attached reactor from the r e a c t o r c e l l .

The twelve hanger rods a r e 1-1/4 i n . i n diameter and about 24 i n . They a r e threaded f o r 3 i n . on each end (opposite hands) w i t h

long.

1-1/2-in.

6-NC threads, and a r e f a b r i c a t e d of INOR-8. A hex section

i n t h e center i s f o r applying a wrench i n t h e turnbuckle arrangement t o l e v e l t h e reactor and t o d i s t r i b u t e t h e load evenly between t h e hanger rods. The support brackets, o r lugs, welded t o t h e r e a c t o r vessel, a r e f a b r i c a t e d of INOR-8and are, f o r the most part, of 3/4-in. plate.

The c e n t e r l i n e of t h e pin hole i s about 1-3/8 i n . from t h e

w a l l of t h e vessel.

The pin i s 1-1/4 i n . i n diameter and i s made of

INOR-8(see ORNL Drawing D-BB-B-40407)

The support arrangement i s such that t h e r e a c t o r vessel can be considered t o be anchored a t t h e support lugs.

The portion of t h e

vessel below t h i s elevation i s f r e e t o expand downward on a temperature r i s e w i t h e s s e n t i a l l y no r e s t r a i n t .

Expansion of t h e portion above

t h e elevation of the support lugs c r e a t e s forces and moments on t h e connecting piping which are considered i n t h e f l e x i b i l i t y analysis of t h e piping, as discussed i n Section 5.6.2, following. The temperature and stress d i s t r i b u t i o n s i n t h e hanger rods were estimated using derived equations and analog computer solutions. 54,55

The reactor vessel and contents weigh about’ 30,000 l b , giving a static stress of about 2000 p s i per rod.

The t o p end of t h e rods a r e cooled

by conduction t o t h e water-cooled thermal-shield cover and a r e assumed t o be a t about 200oF. Assuming t h e lower end of t h e rods t o be a t a maximum of 1250°F, and t h e gamma heating t o be a m a x i m u m of 0.23 w/cc, t h e combination of t h e thermal s t r e s s due t o t h e temperature gradient and t h e s t a t i c load i s a maximum a t t h e cool end

This value i s 7350

125 p s i and i s well within t h e allowable s t r e s s of 24,000 psi f o r INOR-8 A t t h e hot end t h e estimated combined s t r e s s is,~27OOpsi, a t 200'F. which i s within t h e allowable s t r e s s of 3500 p s i a t 13009F. The

maximum temperature occurs about 1/2 i n . from t h e reactor vessel and i s estimated t o be about 1 2 8 0 ~ ~ t h;e combined s t r e s s a t t h i s point w a s determined t o be 2500 p s i . 5.3.10 Thermal Shield The primary functions of t h e thermal shield, which might be more properly c a l l e d t h e " i n t e r n a l shield," a r e t o reduce t h e r a d i a t i o n damage t o t h e reactor containment vessel and t o c e l l equipment, t o serve as p a r t of t h e biological shielding, and t o provide a support for t h e r e a c t o r vessel.

It i s estimated t h a t t h e thermal s h i e l d reduces

t h e t o t a l neutron dosage inside t h e containment vessel by a f a c t o r of

about 10 and attenuates t h e gamma i r r a d i a t i o n by a f a c t o r of about 10 The s h i e l d i s a water-cooled, s t e e l - and w a t e r - f i l l e d container completely surrounding t h e r e a c t o r vessel.

A general e x t e r i o r view of

t h e thermal s h i e l d before i n s t a l l a t i o n i s shown i n F i g . 5.20. The s h i e l d i s about 10.4 f t OD by 7.8 f t I D and 12.5 f t high o v e r a l l . The lk-in.-wide annular space i s f i l l e d with 1-in.-diam carbon s t e e l balls.

The s h i e l d cooling water c i r c u l a t e s through t h e i n t e r s t i t i a l

spaces.

Including t h e 1-in.-thick p l a t e , of which t h e thermal s h i e l d

i s primarily constructed, t h e s h i e l d i s 16 i n . thick, 5@ of which i s i r o n and 5os& i s w a t e r .

Type 304 s t a i n l e s s s t e e l i s used as t h e con-

s t r u c t i o n material because f a s t neutron i r r a d i a t i o n of t h e inner w a l l could r a i s e t h e n i l d u c t i l i t y temperature ("2)of carbon steel above t h e operating temperature i n less than one year of full-power operation. The support s t r u c t u r e , however, i s constructed of carbon s t e e l .

The

weight of t h e complete thermal shield, Including t h e water, i s e s t i mated t o be about 125 tons.

The cooling-water system i s designed t o

remove about 600 kw of heat, but the a c t u a l cooling load i s estimated t o be considerably less than t h i s .

S i x separate pieces make up t h e thermal s h i e l d assembly:

t h e base,

t h e c y l i n d r i c a l section, three removable sections, o r plugs, and t h e removable t o p cover.

The plugs fill t h e s l o t s i n t h e c y l i n d r i c a l s e c t i o n

through which t h e reactor f i l l and drain l i n e , t h e f u e l - s a l t i n l e t l i n e

% 126

Fig. 5.20.

Thermal Shield P r i o r t o I n s t a l l a t i o n .

127

b, %

t o t h e reactor, and t h e f u e l - s a l t o u t l e t l i n e must pass as t h e reactor i s lowered i n t o position. The base and c y l i n d r i c a l section a r e permanently i n s t a l l e d i n t h e r e a c t o r c e l l . (elev)

[See ORNL DWgs E-BB-D-40729

, E-BB-D-40730 (plan), and E-BB-D-40724 (assembly and s e c t i o n s 1 Structural.

5.3.10.1

The base i s e s s e n t i a l l y a f l a t , rectangular

tank about 18 i n . deep which rests on a g r i d of radial beams a t t h e The base bottom of the r e a c t o r c e l l (see O€UiL Dwg. E-KK-D-40723). supports the e n t i r e thermal s h i e l d and t h e reactor vessel and i s t h e anchor point i n t h e f u e l piping system. The base i s welded t o t h e I I

radial support beams t o prevent s h i f t i n g . 8-in.,

20-lb/ft,

wide-flange,

The base contains f i f t e e n

carbon s t e e l I-beams (Asm A-36) arranged

i n two l a y e r s , with t h e s i x beams i n t h e bottom l a y e r a t r i g h t angles t o t h e nine beams i n t h e t o p l a y e r .

The beams are welded t o each other

a t a l l i n t e r s e c t i o n s and t o t h e 3/4-in.-thick

304 stainless s t e e l t o p

and bottom p l a t e s , t h e former being accomplished by 2-in.-diam plug welds on about l 5 - i n . centers. The 3/&-in.-thick 304 s t a i n l e s s s t e e l s i d e p l a t e s a r e welded t o t h e ends of t h e support g r i d beams. Attached t o , and part of, t h e base i s a v e r t i c a l section formed t o f i t t h e i n s i d e curvature of t h e bottom hemispherical head of t h e r e a c t o r

c e l l vessel.

The outer hemispherical p l a t e , t h e inner semicircular

p l a t e , and t h e i n n e r conical-shaped "skirt" p l a t e of t h i s v e r t i c a l proj e c t i o n a r e 1-in.-thick 304 s t a i n l e s s steel. The projection i s i n t e r n a l l y L

-1-

reinforced with six 3 / b i n . - t h i c k radial web p l a t e s . The c y l i n d r i c a l s e c t i o n i s f a b r i c a t e d of 1 - i n . - t h i c k 304 s t a i n l e s s s t e e l and i s 151 i n . high, 125 i n . OD, and 93 i n . I D .

The lk-in.-wide

annulus i s divided i n t o 30" segments by twelve 1-in.-thick radial r e i n f o r c i n g web p l a t e s .

The p l a t e s a r e perforated with 2-in.-diam

holes i n a p a t t e r n t o promote e f f i c i e n t c i r c u l a t i o n of t h e cooling water.

The annulus i s f i l l e d with approximately 70 tons (475 f t 3) of

1-in.-diam carbon s t e e l balls, around which t h e cooling water c i r c u l a t e s .

A l a r g e cutout i n t h e bottom of t h e cyl'inder f i t s over the v e r t i c a l projection on t h e base, mentioned above.

The cylinder i s s l o t t e d i n

t h r e e places t o accommodate t h e r e a c t o r f u e l - s a l t i n l e t (line 102), t h e f u e l - s a l t o u t l e t ( l i n e loo), and t h e r e a c t o r f i l l and d r a i n l i n e ( l i n e 103).

A 37-1/4-in.-ID

pocket i s provided i n t h e s i d e of t h e

r; 128 cylinder f o r t h e neutron instrument tube.

A t two points near t h e

8$ t

inner surface of the thermal shield, a t about t h e northeast and southe a s t positions, 2-in. sched-10 pipes about 10 f t long a r e mounted v e r t i c a l l y t o serve as thimbles f o r the s p e c i a l neutron d e t e c t o r i n s t r u mentation. shield.

These tubes extend about 8 i n . above t h e t o p of t h e thermal

The portion of t h e thimble i n s i d e t h e s h i e l d i s separated

from the 1-in. steel balls by a semicircular s e c t i o n of 8-in. pipe. A similar arrangement a t t h e west-northwest position, but using a

1-1/2-in.

sched-40 pipe, serves as t h e neutron source tube (see

Section 5.3.8). The t h r e e plugs that s l i p v e r t i c a l l y i n t o t h e s l o t s i n t h e c y l i n d r i c a l portion a r e primarily constructed of 1 - i n . - t h i c k 304 stainless s t e e l plate.

The portions that f i t over t h e f u e l i n l e t and

o u t l e t l i n e s include semicircular sections of 20-in. pipe. a r e a l s o f i l l e d with 1 - i n . - d i m carbon s t e e l balls.

The plugs

Each plug i s pro-

vided w i t h 1/2-in. sched-40 cooling-water connections a t t h e top, t h e i n l e t pipe dipping on the i n s i d e t o near t h e bottom of t h e plug. The thermal s h i e l d cover i s f a b r i c a t e d of 1 - i n . - t h i c k 304 s t a i n -

l e s s s t e e l p l a t e and i s about 79-3/4 i n . OD by 16 i n . t h i c k . 22-5/8-in.-dim

hole through t h e center i s provided by a 22-in.-long

s e c t i o n of 24-in. sched-40 pipe; t h e r e a c t o r access nozzle passes The cover i s divided i n t o 30" segments by twelve

through t h i s opening.

1-in.-thick radial reinforcing w e b p l a t e s .

These p l a t e s project beyond

t h e circumference of t h e cover f o r about 4 i n . and r e s t on t h e t o p surface of the c y l i n d r i c a l portion.

The projections, which c a r r y t h e

weight of t h e cover and t h e r e a c t o r vessel, a r e reinforced with 3/8 i n . p l a t e on each s i d e t o give each a t o t a l bearing surface about 1-3/4 i n . wide by 4 i n . long.

The web p l a t e s a r e perforated with 3/4-in.-dim

holes spaced t o promote e f f i c i e n t c i r c u l a t i o n of t h e cooling water. Each of t h e wedge-shaped segments i n t h e cover between t h e r a d i a l p l a t e s contains four 1-in.-thick carbon s t e e l p l a t e s , spaced about 1 - i n . apart, t o serve as shielding. A t the outer circumference of t h e cover a r e sixty-three v e r t i c a l

2-in. pipe penetrations through which t h e r e a c t o r furnace heaters a r e i n s e r t e d (see Section

5.3.11).

A t about t h e northwest p o s i t i o n on t h e

129

LJ le

cover, a 1/4-in.-thick r o l l e d p l a t e sleeve, 5-3/4 i n . ID, provides stccess t o t h e heaters a t t h e freeze valve on t h e d r a i n l i n e , FV-103. Two nozzles of 2-in. sched-40 pipe serve as t h e cooling-water i n l e t and o u t l e t connections. 5.3.10.2

Cooling.

The thermal s h i e l d i s cooled by a flow of about

100 gpm of t r e a t e d water containing potassium n i t r i t e and potassium

borate as corrosion i n h i b i t o r s .

(The treated cooling-water-system

water chemistry i s discussed i n Section 15.2.3). * 3 4

t o t h e thermal s h i e l d through t h e 2-1/2-in.

l i n e 844.

It flows i n

series through t h e base, t h e c y l i n d r i c a l portion, and then through t h e cover.56

A t appropriate points, water i s withdrawn from t h e

c y l i n d r i c a l portion i n l/2-in. t

Water i s supplied

pipes t o flow through one of t h e three

plugs, after which it returns t o t h e c y l i n d r i c a l portion. The cooling water e n t e r s t h e base through a 2-1/2-in.

pipe on t h e

north s i d e and flows through t h e base t o t h e south s i d e and upward through t h e v e r t i c a l projection of t h e base, ducted through t h e 2-1/2-in. portion.

The water i s then con-

l i n e 8 4 4 - ~t o the bottom of t h e c y l i n d r i c a l

The water moves around t h e lh-in.-wide annular space i n a

counter-clockwise d i r e c t i o n (viewed from above), flowing through 2-in. diam holes i n t h e r a d i a l web p l a t e s , which are spaced t o give t h e great-

e s t c i r c u l a t i o n r a t e near t h e t o p of t h e s h i e l d .

Three 1/2-in. pipe

connecticrns a t t h e t o p withdraw some of t h e water f o r c i r c u l a t i o n L

T-

through t h e plugs, a f t e r which it i s returned t o t h e c y l i n d r i c a l portion (see ORNL E-BB-D-40724)

The water leaves t h e c y l i n d r i c a l part of t h e thermal shield through t h e 2-1/2-in,

l i n e 844-B and flows t o t h e cover.

The water

flow i n the cover i s i n a counter-clockwise d i r e c t i o n (viewed from above) and follows a serpentine course as a r e s u l t of t h e spacing of t h e 3/4-in. -dim holes i n t h e r a d i a l web p l a t e s (see ORNL Dwg.

E-BB-D-40727). The water leaves the t o p cover through a 2-1/2-in. pipe ( l i n e 845). The cooling-water system was designed t o remove about 600 kw

(2 x 10 Btu/hr) of heat, A t a flow rate of 100 gpm, t h e temperature r i s e of t h e water flowing through t h e thermal s h i e l d i s about 402'F. I n case of l o s s of water flow, t h e heat capacity of t h e material i n n

130 t h e s h i e l d i s such that t h e reactor operation could continue a t I

t h e 10-Mw reactor power l e v e l f o r about 3 h r before t h e water temperat u r e would r i s e s u f f i c i e n t l y t o c r e a t e a vapor pressure exceeding t h e design value of 20 psig. 57 5.3.10.3

Mechanical Design.

The vessel was designed i n accordance

with t h e provisions i n the ASME Unfired Pressure Vessel Code, Section

VIII.45

It w a s hydrostatically t e s t e d a t 32 p s i g a t room temperature, 58

A 1/2-in. relief valve, s e t a t 20 psig, i s incorporated i n t h e cooling-

water supply system.

As a f u r t h e r protection, t h e cooling-water circu-

l a t i n g pump has a pressure-actuated cutoff switch i n t h e discharge s e t

a t 22 psig. I

5.3.10.4

Shielding Considerations.

Radiation damage t o t h e s t e e l

i n t h e containment vessel w a l l i s not considered t o be a s i g n i f i c a n t problem unless t h e fast neutron (slMev) exposure exceeds l O I 8 n/cm 2 59

This would be a n exposure corresponding t o 10 y r of operation a t a 10-Mw r e a c t o r power l e v e l with t h e containment vessel exposed t o a fast 9 2 f l u x of 3 x 10 n/cm -sec. The thermal s h i e l d has a t o t a l thickness of

16 i n , 5@

of which i s Fe and 5 6 i s H20, a 12-in. gap between t h e

r e a c t o r and the shield, and a n estimated escaping neutron f l u x of about 1.5 x 10 8 n/cm 2-sec. 59 The biological shielding required i n t h e roof above t h e r e a c t o r i s not materially reduced by t h e presence of t h e thermal s h i e l d i n that t h e aforementioned 22-5/8-in. -dim hole through t h e center of t h e thermal-shield cover permits d i r e c t impingement of r a d i a t i o n from t h e r e a c t o r vessel over a f a i r l y wide a r e a of t h e roof plugs.

The thermal

s h i e l d does, however, make an important reduction i n t h e amount of biological shielding needed a t the coolant-salt penetrations of t h e containment vessel w a l l . A s previously s t a t e d , t h e cooling-water system i s capable of

removing 600 kw of heat.

The nuclear heating i n t h e thermal s h t e l d

i s expected t o contribute t o less than 100 kw of heat.

The amount of

heat transmitted from t h e r e a c t o r furnace t o t h e thermal s h i e l d through

t h e thermal i n s u l a t i o n i s estimated t o be l e s s than 50 kw.

131

5.3.11

Heaters The 11-in.-wide annular space between the thermal insulation on

the inside of the thermal shield and the reactor vessel w a l l i s heated by e l e c t r i c a l resistance-type heaters t o form a furnace. A t o t a l of about 68 kw of heat can be supplied by one-hundred twenty s i x lengths of 3/8-in. by 0.035-in.-wall-thickness Inconel tubing, each 8 f t 7-1/2 i n . t o 9 f t 11 i n . long, through which the current i s passed (see ORNL Dwg. ~ - ~ ~ - ~ - 5 6 2 2This 5 ) . furnace provides the heat t o the reactor 7

vessel during warmup and maintains the vessel a t temperature during low-power operation. The reactor furnace heater tubing i s i n the form of sixty-three U-tubes, which are arranged i n nine removable sections of seven U-tubes each. Each of the U-tubes i s inserted i n a 2-in.-OD by 0.065-in,-wa~thickness 304 stainless steel thimble, which i s suspended from the top cover of the thermal shield. The tops of the thimbles extend about 6 i n . above the top cover and are flared t o about 2-3/8 in. i n diameter t o f a c i l i t a t e insertion of the heater U-tubes. The centers of the thimbles a r e about 2.615 in. from each other and about 1-7/8 in. from

the insulation can. The distance between the centers of the legs of t h e U-tubes i s 3/4 i n . The U-tube assemblies a r e suspended from the junction box f o r each assembly. The junction boxes are fabricated of 11-gage 304 stainless steel, a r e about 4 in. by 4 in. i n cross section and about 18 i n . long, and are curved longitudinally t o the segment of a c i r c l e about 37-1/2 i n . i n radius. The junction boxes s i t on top of the thimbles which pass through t h e thermal shield cover. Each junction box i s provided with a l i f t i n g b a i l a t the center of gravity t o permit withdrawal of t h e seven U-tube assemblies as a complete unit. The seven U-tubes i n each section a r e e l e c t r i c a l l y connected i n series s o t h a t each junction box has but two e l e c t r i c a l power leads. The lead wire inside the junction box i s solid N o , 10 Alloy 99 softtemper nickel, insulated with fish-spine ceramic beads (Saxonburg Ceramic Company Part No. P-897). The lead wires a r e connected t o a male plug mounted on top of the junction box. The matching female socket i s f i t t e d with a l i f t i n g b a i l t o f a c i l i t a t e remote manipulation.

132 The socket i s connected by cables t o t h e terminal boxes mounted on

Ir'

t h e support s t r u c t u r e .

The t o p 3l-l/2 i n . of each heater U-tube l e g i s constructed of s o l i d Inconel rod, 3/8 i n . i n diameter, and therefore does not heat t o as high a temperature as t h e lower tubular portion.

The s o l i d rod

i s formed a t t h e t o p t o e l e c t r i c a l l y connect t h e U-tubes i n s e r i e s .

About 27 i n . of t h e upper portion of each U-tube assembly i s s t i f f e n e d by being incased i n a 1-5/8-in. -OD by 0.065-in.-wa11thickness 304 s t a i n l e s s steel tube.

Ceramic i n s u l a t o r s (American

Lava Company, Type A) position t h e U-tube l e g s within t h i s tube.

Ceramic standoff i n s u l a t o r s of t h e same material a r e a l s o spaced

a t regular i n t e r v a l s along t h e lower l e g s of t h e U-tubes t o prevent t h e i r contact with t h e thimble w a l l s . The U-tubes i n f i v e of the sections a r e about 12 f t long o v e r a l l ,

including t h e s o l i d portions, and those i n t h e remaining four sections a r e about 1 f t shorter.

The short tubes are required i n t h e southwest

quadrant of t h e furnace where t h e thermal s h i e l d i s shortened by t h e proximity t o the curved w a l l of t h e containment vessel.

The U-tubes

i n each section a r e staggered i n length byNl/2 i n . , w i t h t h e longest U-tube i n t h e center of t h e a r r a y of seven.

This arrangement f a c i l i -

t a t e s i n s e r t i o n of t h e U-tubes i n t o t h e thimbles. The e l e c t r i c a l input t o t h e reactor furnace heaters i s controlled manually i n response t o indicated temperature readings.

There a r e

t h r e e controllers, each serving three junction boxes, o r sections. The e l e c t r i c a l c i r c u i t s f o r the power supply t o t h e heaters i s described

i n Section 19.7.

The reactor heaters a r e not connected t o t h e Diesel-

driven emergency power sypply. The annular space between t h e reactor furnace and t h e thermal shield w a l l i s thermally insulated t o a built-up thickness of

6 in.

with "Careytemp 16OOoF" block insulation, covered with 16-gage 304 s t a i n l e s s s t e e l sheet, on t h e side, bottom, and t o p (see Section 5.6a6.3),

133

5.4 Fuel Circulation Pump The f u e l - s a l t c i r c u l a t i o n pump i s a c e n t r i f u g a l sump-type pump w i t h an overhung impeller.

It i s driven by a 75-hp e l e c t r i c motor

a t d1160 rpm and has a capacity of about 1200 gpm when operating a t a head of 48.5 ft. The 36-in.-diam pump bowl, or tank, i n which t h e pump volute and impeller a r e located, serves as t h e surge volume and expansion tank i n t h e primary c i r c u l a t i o n system.

A small tank located

beneath t h e pump and connected t o it through an overflow l i n e provides a d d i t i o n a l volume f o r expansion of f u e l under abnormal conditions. A general description of t h e pump was given i n Section 2.6.2

and Fig. 2 . 3 , which i s a simplified cross-sectional drawing of t h e pump. I

Figure 5.21 i s an e x t e r i o r view of t h e pump. pump a r e summarized i n Table 5.5.

The basic data f o r t h e

The general location of t h e f u e l

c i r c u l a t i o n pump and overflow tank within t h e r e a c t o r c e l l i s i n d i cated i n Figs. 4.4 and 4.5. The sampler-enricher system, which can add o r withdraw small q u a n t i t i e s of f u e l s a l t f r o m t h e pump bowl v i a l i n e 999 i s described i n Section 7 and i s not included i n t h i s discussion of t h e pump. A l l parts of t h e pump i n contact with t h e f u e l salt a r e fab-

r i c a t e d of INOR-~. The pump i s of a design similar t o those used extensively a t ORNL f o r c i r c u l a t i o n of molten salts and l i q u i d metals.

The pump w a s

f i r s t t e s t e d a t simulated r e a c t o r conditions of speed, flow and head using

water i n a c i r c u l a t i n g 1 0 o p . ~ It w a s subsequently t e s t e d with molten

salt a t r e a c t o r conditions, including those of pressure and temperature. The f u e l and coolant-salt pumps were machined and assembled a t t h e machine shops of t h e Y-12 Plant i n Oak Ridge.

Castings f o r t h e

volutes and impellers were made a t General Alloys Company (Boston).

The ASME dished heads f o r t h e pump bowls, or tanks, were f a b r i c a t e d

a t Lukins S t e e l Company (Philadelphia)62 from INOR-8 material furnished by ORNL.

The pump motors were purchased from Westinghouse E l e c t r i c

Corporation (Buffalo) 63 The pressure vessels and t h e s e a l s needed where t h e e l e c t r i c leads pass through t h e vessel, or "can," were obtained by Westinghouse by subcontract with E m i l Vondungen Company (Buffalo).

Fabrication of t h e drive motors w a s covered by ORNL speci-

135 Table 5.5. Design flow:

Fuel-Salt Circulation hunp Design Data

1200

pump output,> g p i n t e r n a l bypass, gpm .I

Intake pressure, psig

65 48.5 c355 @7

Impeller diameter, i n .

11.5

Head a t 1200 p, f t Discharge pressure, psig

1160

Speed, rpm Intake nozzle (sched bo), i n . IPS

Discharge nozzle (sched 40), i n . IPS

Pump bowl:

36 15

diameter, i n . height, i n .

Volumes, f t 3 Minimum s t a r t i n g and normal operating (including volute)

4.1

Maximum operating

5* 2

Maximum emergency (includes space above vent)

6.1

N o r m a l gas volume

2 .o

Overall height of pump and motor assembly, f t 3

8.6

Design conditions:

pressure, psig

temperature, O F

1300

Supply, v ( a l t e r n a t i n g current)

75 480 450

Motor Rating, hp

S t a r t i n g (locked r o t o r ) current, amp

Tne NEMA c l a s s

Squirrel-cage induction

Lubrication

California Research Corporation NRRG-159

Electrical insulation

Class H

Design r a d i a t i o n dosage f o r e l e c t r i c a l insulation, r

2 x 1o1O

Estimated r a d i a t i o n l e v e l , r/hr Overflow tank volume, f t 3

105

5.4

136 i

f i c a t i o n s . &,65

Testing of t h e completed pumps was performed by

personnel of t h e ORNL Reactor Division.

Complete assemblies of motors

and r o t a t i n g parts were provided f o r four pumps--two f o r t h e f u e l s a l t system and two f o r t h e coolant-salt system--in order t o have a

spare pump on hand f o r each system. The pressure-containing parts, which include t h e drive-motor housing, t h e bearing housing, pump bowl, l u b r i c a t i o n reservoir, l u b r i cant passage, nozzles, t h e overflow tank, e t c . , were a l l designed i n accordance w i t h Section VI11 of t h e ASME Boiler and Pressure Vessel Code47 and Code I n t e r p r e t a t i o n Cases 1 2 7 0 and ~ ~ ~ 1273N5' f o r primary vessels. A l u b r i c a t i n g - o i l system i s required f o r each pump.

The o i l -

c i r c u l a t i o n pump, cooler and storage tank, and f i l t e r a r e located i n t h e secondarily shielded tunnel area outside t h e reactor c e l l . The l u b r i c a t i o n system i s described i n Section 5.4.1.4,

following.

I n order t o prevent salt from g e t t i n g i n t o t h e gas and lubricant passages, e t c . , on too high a l e v e l i n the pmp bowl, an overflow pipe leads t o a catch tank located d i r e c t l y beneath t h e pump.

This

overflow tank i s described i n Section 5.4.7. Other a u x i l i a r y systems a r e the cooling water, which i s c i r c u l a t e d i n a c o i l around t h e pump-motor vessel, t h e cover gas, and t h e cooling gas, which i s directed around t h e e x t e r i o r of t h e upper portion of t h e

pump bowl. The pump i s designed t o operate a t a synchronous speed of

d l 6 0 rpm. If it proves desirable t o conduct experiments i n t h e MSFE other than design flow r a t e s , t h e pump speed can be changed by varying t h e frequency of t h e e l e c t r i c a l input t o t h e motor through use of a

motor-generator s e t , which can be brought t o t h e MSRE s i t e and operated on a t r u c k - t r a i l e r u n i t .

5.4.1

Description The f u e l - s a l t pump consists of t h r e e principal assemblies:

(1) t h e rotary-element assembly, which includes t h e r o t a t i n g s h a f t and

impeller, t h e bearing housing and bearings, t h e s h i e l d block, and t h e impeller cover p l a t e and upper labyrinth subassembly; (2) t h e pump bowl, which contains t h e volute and has i n l e t and o u t l e t nozzles; and (3) t h e drive-motor assembly.

L' &

137

The motor can be removed by unbolting it from t h e bearing-housing upper flange.

A splined coupling joins t h e motor shaft t o t h e pump

drive shaft s o that t h e motor can be withdrawn.

The rotary-element

assembly can be removed by unbolting t h e lower bearing-housing flange from t h e pump-bowl flange.

Each of t h e twenty-four b o l t s i n t h i s

flange has an extension with universal j o i n t s which allow t h e b o l t s t o be turned w i t h simple socket wrenches w i t h extension handles operated from d i r e c t l y above t h e u n i t (see ORNL Dwg. F-RD-9830-F).* Both t h e flanges mentioned above have ring-joint leak-detected closures. A l l water cooling l i n e s , gas l i n e s , l u b r i c a t i n g - o i l l i n e s , e t c . , which

serve t h e removable motor and rotary-element assemblies, have s p e c i a l

disconnect couplings t o f a c i l i t a t e disengagement using remotely operated tooling.

5.4 .I.1 Rotary-Element Assembly. The rotary-element assembly c o n s i s t s of t h e 347 s t a i n l e s s steel bearing housing, which i s about 8 i n . i n diameter by 23 i n . long and has a 29-1/2-in.-diam flange a t the upper end and a 23-in.-diam flange a t t h e lower end. The pump s h a f t , which i s -3 i n . i n diameter by 48 i n . long, passes through t h i s housing and i s supported by ball bearings. The upper bearing i s an SKF-7317BG angular contact type i n a face-to-face duplex configuration which absorbs both radial and t h r u s t forces.

The lower bearing i s an

SK-7219 angular contact type i n a back-to-back duplex configuration which absorbs radial forces and provides additional s t i f f n e s s f o r t h e

shaft.

bearing.

The impeller i s overhung about 22 i n . beneath t h e lower

Both bearings a r e l u b r i c a t e d and cooled t o an operating

temperature of about 150°F by a 4-m flow of o i l supplied through l i n e 703 and leaving v i a l i n e 706.

The l u b r i c a t i o n system w i l l be

described subsequently i n Section 5.4.1.4. Contact-type s e a l s are located above and below the bearings t o confine t h e o i l t o t h e l u b r i c a t i o n system.

The seals have s t a t i o n a r y

graphitar rings (U. S. Carbon Company) supported on f l e x i b l e s t a i n l e s s s t e e l bellows (Rovertshaw-Fulton Company) that bear against case-hardened, low carbon steel rings mounted on t h e pump s h a f t .

LJ t

*ORNL drawings f o r t h e MSRE pumps have a d i f f e r e n t numbering system than t h a t used f o r a l l other MSRE drawings.

c 4

The seal assemblies were manufactured i n t h e machine shops of t h e Y-12 Plant i n Oak Ridge. The s e a l s a r e of t h e balanced-piston type

4& J

and a r e designed t o operate normally with a pressure on t h e l u b r i c a n t s i d e 2 t o 8 p s i higher than that i n t h e pump bowl, which i s a t about

5 psig. Under these conditions t h e lower s e a l can accept, without opening, pressure t r a n s i e n t s i n t h e pump bowl as high as 65 p s i a o r as low as 1 psia. A catch basin located above t h e coolant passages i n t h e shield

plug ( t o be described subsequently) c o l l e c t s any lubricant t h a t leaks past t h e lower shaft s e a l .

This seepage i s conveyed from t h e r e a c t o r

c e l l through l i n e 524 t o an o i l catch tank.

The gas t h a t accompanies

t h e o i l seepage i s disposed of through t h e off-gas system.

The

amount of o i l leakage, which i s estimated t o be l e s s than 40 cc/day, can be measured and compared t o t h e reduction of t h e o i l i n t h e l u b r i c a t i o n system reservoir.

A t t h i s r a t e of o i l l o s s t h e system

could operate f o r more than a year before an o i l addition t o t h e o i l reservoir would be necessary.67

The o i l catch tank, however, i s

limited 90 days storage capacity f o r t h e same l e a k r a t e . The gas pressure on t h e l u b r i c a n t (upper) s i d e of t h e lower shaft s e a l i s maintained equal t o that i n t h e gas space above t h e o i l l e v e l i n t h e l u b r i c a t i o n system r e s e r v o i r located i n t h e tunnel a r e a by interconnection through t h e breather pipe ( l i n e 590).

The gas pressure

on t h e lower side of t h i s s e a l i s that of t h e helium cover gas i n t h e pump bowl, o r normally about 5 psig. Helium gas i s introduced i n t o t h e pump-shaft annulus j u s t below t h e lower shaft s e a l through l i n e 516 a t a maximum r a t e of 0.084 scfm. A small p a r t of t h i s gas flows out through l i n e 524 t o prevent migration

of o i l vapor t o t h e f u e l salt i n t h e pump bowl; t h e remainder flows down t h e annulus t o prevent t h e migration of radioactive gases and p a r t i c u l a t e s from t h e s a l t region i n t o t h e lower s h a f t - s e a l a r e a

68 and

serves as the main flow of sweep gas f o r removal of f i s s i o n product gases from t h e pump bawl.

The pressure drop i n t h e gas flow through

t h e pump from l i n e 516 t o 524 i s about 0.25 i n . H20 a t design flow conditions. Section 12.

The offgas system w i l l be described subsequently i n

- 1

An INOR-8shield block, which i s 13 1/2 in. i n diameter by -8 in. i

t h i c k and has a hole a t t h e center f o r t h e pump shaft, i s bolted t o t h e bottom of t h e lower bearing housing flange.

T h i s block provides

some shielding f o r t h e o i l i n t h e bearing housing and f o r the pump motor against i r r a d i a t i o n by t h e f u e l s a l t i n t h e pump bowl. withdrawn a s p a r t of t h e r o t a r y element assembly.

It is

The block i s

cooled by an 8-gpm flow of o i l supplied through l i n e 704 and leaving with t h e l u b r i c a t i n g o i l through l i n e 706.

The cooling o i l flows

through grooves 1/4 in. deep by 3/4 in. wide, s p i r a l i n g from t h e

3 in. t o 10 1/2 in. i n diameter on t h e upper surface of t h e plug. The estimated heat t o be removed t o maintain t h e lower shaft s e a l temperature t o an acceptable value i s about 18,000 Btu/hr. 69 The 11.5-in.-diam

impeller i s keyed t o the lower end of the

INOR 8 pump shaft and retained by a b o l t tack welded i n place.

s l i n g e r r i n g i s located on t h e shaft j u s t above t h e impeller. The pump shaft speed i s sensed continuously with a magnetic reluctance pickup (Electro Point 721280) u t i l i z i n g an i n t e r r u p t e r gear t h a t i s i n t e g r a l with t h e lower portion of t h e shaft coupling (see ORNL Dwg. F-9830-62).

The output of t h i s pickup (SI FP-E) i s

transmitted t o a speed indicator, t h e control c i r c u i t and alarm system, and t o t h e data logger.

The direction of r o t a t i o n can a l s o

be sensed by t h e pickup. Labyrinth-type s e a l s a r e used on t h e impeller i n l e t shroud (lower labyrinth) and on t h e impeller support shroud (upper labyrinth) as shown i n Fig. 5.22.

The upper labyrinth i s i n t e g r a l with t h e

impeller cover plate, which i s sealed t o t h e volute with a 1/4-in.

INOR-8O-ring about 12.75 i n . I D .

Labyrinth s e a l s are a l s o pro-

vided on t h e shaft a t each of t h e aforementioned contact s e a l assemblies. 5.4.1.2

Pump Bawl.

The pump bowl, o r tank, i s about 36 in. i n

diameter and 17 in. high at t h e centerline.

It i s formed of two INOR-8

ASME dished heads with a w a l l thickness of 1/2 in.

The normal f u e l s a l t

l e v e l i n t h e bowl i s about 11 in. from t h e bottom, measured a t t h e cent e r l i n e . The pump volute i s an Allis-Chalmers 8- by 6-in. Type SSE (AllisChalmers Dwg. 52-423-498) with 5/8-in.

w a l l thickness.

The 8-in. -IPS

UNCLASSIFIED ORNL-DWG. 64-6902

LOWER LABYRINTH

(a) CLEARANCES AT IMPELLER SEALS

(b) BRIDGE TUBE

FIG. 5.22. FUEL-SALT PUMP BRIDGE AND IMPELLER SEAL CLEARANCES

141 sched-40 i n l e t nozzle on t h e bottom of t h e bowl i s concentric with t h e c e n t e r l i n e of t h e pump.

The volute e n t r y nozzle and t h e impeller

i n l e t opening are a l s o 8 i n . i n diameter.

The pump discharge from

t h e volute i s through a s p e c i a l thimble, 5 i n . I D by 7 i n . long, having s p h e r i c a l l y shaped ends.

(See O

m Dwg. D-2-02-054-10065-A).

The

spherical portions f i t i n t o s i m i l a r l y shaped s e a t s i n t h e volute and i n t h e pump-bowl discharge nozzle (see Fig. 5.22).

This bridge tube

provides t h e f l e x i b i l i t y needed t o absorb the three-dimensional r e l a t i v e motions between t h e volute and t h e bowl and a t t h e same time allows only a small bypass flow through t h e j o i n t s back i n t o t h e pump bowl,

A second bypass flow, c a l l e d t h e "fountain flow," escapes through t h e clearance between t h e t o p s i d e of t h e impeller and t h e pump casing, and thence through t h e clearance between t h e pump shaft and t h e pressure breakdown bushing.

With t h e clearances shown i n Fig. 5.22, t h e fountain

flow i s estimated t o be about 1 5 gpm ( r e f 60, p 27). A t h i r d bypass flow, termed t h e " s t r i p p e r flow," of about 60 gpm

i s taken from the pump-bowl discharge nozzle i n t o a r i n g of 2-in.-diam pipe e n c i r c l i n g t h e vapor space i n s i d e t h e pump bowl on a radius of about l 5 - l / 2 i n .

This d i s t r i b u t o r has regularly spaced holes, half about

1/16 i n , and half 1/8 i n . i n diameter, oriented about 30" from t h e horizontal and pointing downward toward t h e center of t h e pump bowl. The holes are about 1 i n . above t h e normal f u e l - s a l t l e v e l i n t h e bowl. The bypass flow i s sprayed from these holes i n t o t h e bowl t o promote t h e release of f i s s i o n $roduct gases 'to t h e vapor space.

The e f f i c i e n c y

of t h i s s t r i p p i n g a c t i o n i s estimated t o be s u f f i c i e n t t o reduce the 135Xe poison l e v e l i n t h e r e a c t o r t o less t h a t Z$ i n Ak/k.

The i n -

fluence of residence-time d i s t r i b u t i o n on f i s s i o n product decay i n t h e , ~ ~ t h e e f f i c i e n c y of xenon removal and t h e pump bowl was i n ~ e s t i g a t e d and effectiveness of t h e purge gas system were studied p r i o r t o completion of t h e pump design. 7a,72

The same spray holes serve as vents f o r t h e

gas i n t h e pump discharge ( l i n e 101) during preoperational f i l l i n g

of t h e system with molten salt.

i s withdrawn through l i c e 521.

This gas, after venting i n t o t h e bowl,

142 The bypass flows c i r c u l a t e downward through t h e pump bowl and reenter t h e impeller.

The spray entrains a considerable volume of cover

gas i n t h e l i q u i d , and t h e tendency f o r t h i b entrainment t o enlter t h e

pump i s l a r g e l y controlled by a b a f f l e on t h e volute.

Tests indicated

t h a t t h e l i q u i d returning t o t h e impeller w i l l contain 1 t o 2 v o l $

of gas. A 1-1/2-in.

v e r t i c a l sched-40 nozzle i s provided a t t h e t o p of

t h e pump bowl t o allow a capsule t o be lowered i n t o t h e s a l t i n t h e A cap-

bowl t o take a sample o r t o add small amounts of enriched f u e l .

sule guide and l a t c h s t o p inside t h e pump bowl positions t h e sample capsule. 59 The sampler-enricher system i s described i n Section 7. Th;

l i q u i d l e v e l i n t h e pump bowl i s sensed by bubbler-type probes.

One of t h e 1/2-in.-IPS

bubbler tubes ( l i n e 596) extends about 3-7/8 i n .

below the centerline of t h e pump volute, o r a min. of 6-1/8 i n . below t h e salt l e v e l i n t h e bowl.

The other ( l i n e 593) extends t o about 1-15/16

i n . below t h e centerline of t h e volute.

A t h i r d 1/2-in.

connection

( l i n e 592) a t t h e top of t h e pump bowl provides t h e reference pressure as helium gas i s bubbled through t h e two tubes.

Through previous C a l i -

bration, t h e helium pressures can be converted t o l i q u i d l e v e l ; a l s o t h e difference i n pressure between t h e two probes a t d i f f e r e n t l e v e l s may possibly be t r a n s l a t e d i n t o approximate s a l t d e n s i t i e s .

The

bubbler system i s f u r t h e r described i n Section 10.9.1. A pump-bowl overflow pipe ( l i n e 520) releases s a l t t o t h e overflow

tank i n event t h e salt l e v e l i n t h e c i r c u l a t i o n system becomes too high. 73 The lower portion of t h e pump bowl i s cooled by t h e flow of f u e l

salt.

Above t h e l i q u i d l e v e l , however, heat produced a t a r a t e of about

1 5 kw through beta and gamma absorptions would tend t o overheat t h e metal and would cause undesirably high thermal s t r e s s e s unless cooling i s provided.

The t o p portion of t h e bowl i s f i t t e d with a shroud

t h a t is spun from 305 stainless s t e e l and i s about 38 i n . i n diameter; a space 1/4 i n . t o 1 i n . wide i s provided between t h e shroud and t h e

pump-bowl surface through which cooling gas can be directed (see ORNL Dwg. E-47296). The estimated quantity of cooling gas (95$ N2, required i s about 400 cfm (STP). 74

5$ 02)

b 4

143

5.4.1.3

Drive Motor.

The pump drive motor i s a Westinghouse

t o t a l l y enclosed, water-cooled, explosion-proof, NEMA Design "B," special-purpose, squirrel-cage induction motor of 75-hp capacity.

It i s r a t e d a t 480 v and normally has a s t a r t i n g (locked r o t o r ) current demand of 450 amp.

The s t a r t i n g torque i s s l i g h t l y l e s s than

135% of f i l l - l o a d torque, and t h e pull-out torque i s s l i g h t l y l e s s than 20&

of t h e f i l l - l o a d torque.

It i s planned t h a t t h e motor w i l l normally run a t synchronous speed of rr1160 rpm.

Operation at d i f f e r e n t speeds can be obtained

by varying t h e frequency of t h e e l e c t r i c power supply through use of

a motor-generator s e t which can be brought t o t h e E R E s i t e . The drive motor i s d i r e c t l y connected t o the pump s h a f t through

a modified f l e x i b l e coupling (Thomas Flexible Coupling Company Cat. N o . 263 DBZj a l s o see ORNL Dwg. D-2-02-054-9848).

coupling does not require l u b r i c a t i o n .

T h i s type of

The motor shaft i s splined

t o s l i p i n t o t h e coupling t o f a c i l i t a t e removal of t h e motor. The e l e c t r i c a l i n s u l a t i o n used i n t h e motor i s Class "H",

designed

for l5OV ambient conditions and a r a d i a t i o n dosage of 2 x 109 r before mechanical breakdown and a t o t a l dosage of 2 x''01 breakdown75 (also, see ref 66, p 52).

r before e l e c t r i c a l

The background r a d i a t i o n i n t h e

region of t h e pump motor w a s estimated t o be i n t h e order of

lo5 x

rad/hr. 76 A three-conductor, mineral-insulated, copper-covered cable

connects t h e motor t o a three-prong plug that can be i n s e r t e d i n t o a receptacle by a remotely operated manipulator t o o l of t h e type described i n Section 19.7.5.

The e l e c t r i c a l l e a d a e a l through t h e pressure-tight

motor housing i s a ceramic type. The motor housing, o r can, i s surrounded by a water c o i l through which about 5 gpm o f , t r e a t e d , demineralized water i s introduced through t h e 1-in. sched-40 pipe ( l i n e 830) and leaves through l i n e 83.

The

11/16-in. OD x 1/16-in. w a l l thickness s t a i n l e s s s t e e l tubing i s h e l i a r c welded t o the can using s t a i n l e s s s t e e l f i l l e r rod. The lower end of t h e motor casing i s flanged and i s bolted t o t h e t o p flange of t h e bearing-housing assembly by use of a ring-joint leakdetected type of closure.

The motor casing i s f a b r i c a t e d of ASTM A-201

Grade A carbon s t e e l t o meet t h e requirements of t h e ASME Boiler and

144 Pressure Vessel Code47 and must pass a mass spectrometer l e a k t e s t with

a l e a k rate of l e s s than 1 x lom8 cc of helium per second (STP).

5.4.1.4

Lubricating-Oil System.

The o i l system serves t o l u b r i -

c a t e and cool t h e pump beariqgs and t o cool t h e s h i e l d plug located between t h e bearings and t h e pump bowl.

The f u e l - s a l t pump and t h e coolant

s a l t pump have separate l u b r i c a t i n g - o i l systems, but they a r e interconnected so that one system could serve both pumps i n an emergency s i t u a t i o n . Each l u b r i c a t i n g - o i l system c o n s i s t s b a s i c a l l y of a water-cooled o i l reservoir, two c e n t r i f u g a l pumps connected i n p a r a l l e l , and an o i l f i l t e r as shown i n t h e l u b r i c a t i o n system flowsheet, F i g . 5.23 (ORNL Dwg. D-AA-

A-40885).

The equipnent i s located i n t h e e a s t tunnel (see Fig. 4.4),

which i s a secondarily shielded area.

The design d a t a f o r t h e l u b r i c a t i o n

system a r e presented i n Table 5.6. The l u b r i c a t i n g o i l i s a turbine-grade, p a r a f f i n i c base, lo@ s t r a i g h t mineral o i l having a v i s c o s i t y a t 100°F of 66 SSU.

Other

l u b r i c a t i n g - o i l properties are shown i n Table 5.7.

The lubricating-

o i l s p e c i f i c a t i o n s a r e discussed i n reference 77.

Investigation of

t h e o i l temperature a f t e r cessation of t h e o i l flow i n an accidental s i t u a t i o n determined that t h e temperature would not exceed about 500°F, t h e approximate condition at which o i l damage would become appreciable, u n t i l about 10 min a f t e r t h e o i l flow stopped. 78 The o i l r e s e r v o i r i s a carbon s t e e l tank, 22 i n . i n diameter by 32 i n . high, w i t h ASME dished heads 1/4 i n . t h i c k .

The tank i s surrounded

by eight t u r n s of a water-cooled c o i l of 1-in.-diam copper tubing. required water flow r a t e i s about 10 gpm of 85°F water.

The

The i n s i d e

surface of t h e tank i s provided with passageways, about 2 i n . by 3/8 i n . , t o d i r e c t a 5 O - w bypass flow of o i l from t h e pump against t h e tank w a l l a t a n average v e l o c i t y of about 21 f p s .

The o v e r a l l heat-transfer

c o e f f i c i e n t i s estimated a t 230 Btu/hr-ft2-OF,

and t h e maximum heat-

removal rate a t 41,000 Btu/hr (see ref 66, p 57). The o i l reservoir i s provided with a l i q u i d - l e v e l indication,

LI-OTI, t h e output of which i s f e d t o t h e data logger and t h e alarm system.

I n event of a drop i n o i l l e v e l , indicating an o i l l e a k past

t h e lower shaft s e a l of t h e pump, t h e flow control valve FSV-703 automatically stops t h e flow of o i l t o t h e pump.

d j

A l a r m s a r e a l s o provided

I I

m m

I u

I I

i I

. . .

........

. .

-~_.

146 Table 5.6. O i l supply temperature,

Lubricating-Oil System Design Data

Coolant o i l flow t o shield plug, gpm O i l seepage through shaft s e a l s (max), cc/day

140"I? 4 8 40

Outside dimensions lube o i l package (1 x w x h ) , i n .

100 x 34 x 50

Estimated weight, empty, l b .

2200

O F

O i l flow t o pump bearings, gpm

O i l reservoir

Operating volume, gal

Total volume, gal Volume of o i l i n system, gal T a n k height, i n .

43 34 32

Tank outside diameter, i n .

Material

ASME SA-201 Grade A

carbon s t e e l Allowable s t r e s s , psig Design pressure, psig

13,750 75

Design temperature, OF

200

Heat removal capacity, Btu/hr

41,000

O i l circulating pumps (2) (Allis-Chalmers 2 x 1.5

Type

Capacity of each, a t 160 f t head, gpm

Motor (Type TENV Frame cm-718), hp

5 5.25 3500, 6-5, 3 i n .

Power input ( r a t e d ) , kw a t 220 v Speed, rpm, and impeller dim, i n . Design pressure, psig

210

Design temperature, OF

225

O i l filter

Type Size, i n . Material Residence times I n reactor c e l l , sec I n coolant c e l l , sec

...

Cuno EFS

2-114 by 8 Carbon s t e e l

18 4

147 f o r high o i l temperature, low o i l flow r a t e s , o r high lube o i l pump motor temperature. A blanket of helium gas i s maintained over t h e o i l i n t h e reservoir

tank.

The helium supply l i n e ( l i n e 513) and t h e off-gas vent ( l i n e 535)

a r e provided with pressure-control valves (PCV-513 A - 1 and A-2) t o maintain t h e gas pressure a t about 7 psig. e s s e n t i a l l y zero.

The gas flow r a t e i s

The t o p of t h e o i l reservoir tank i s vented t o t h e

bearing housing on t h e f u e l pump through l i n e 590.

The helium pressure

above t h e salt i n t h e pump bowl i s about 5 psig. V #

Two 5-hp Allis-Chalmers "Electric-Cand" c e n t r i f u g a l o i l pumps, 2 x 1.5, type MH, a r e connected i n p a r a l l e l , e i t h e r one of which h8s

s u f f i c i e n t capacity i f used alone.

The pump motor i s cooled by a

small i n t e r n a l by-pass o i l stream.

About 50 g p m of t h e pump output

i s returned t o t h e o i l r e s e r v o i r as a bypass flow t o promote heat t r a n s f e r a t t h e tank w a l l . The o i l f i l t e r i s a standard Cuno EFS f i l t e r using carbon s t e e l

f i l t e r elements. Radiation monitors (RIA-OTI) a r e located i n each l u b r i c a t i o n system t o d e t e c t contamination of t h e o i l o r t h e blanket helium gas, The l u b r i c a t i n g - o i l system equipment i s compactly arranged i n t o a 7

"package" which can be conveniently shielded with l e a d bricks.

The

valves have extension handles passing through t h e lead s h i e l d . Sampling nozzles a r e located on o i l l i n e s external t o t h e package f o r Q

periodic sampling of t h e o i l f o r both r a d i a t i o n and thermal damage.

5.4.1.5

O i l Catch Tank.

,Lubricating o i l seeping past t h e lower

shaft seal of t h e pump i s pipeld from t h e r e a c t o r c e l l through 1/2-in.

l i n e 524 t o an o i l catch tank located i n t h e s p e c i a l equipment room. The portion of t h e l i n e i n s i d e t h e r e a c t o r c e l l i s shielded t o reduce t h e amount of induced a c t i v i t y i n t h e o i l . cated of a 46-1/2-in.-long by a 20-in.-long

The catch tank i s f a b r i -

s e c t i o n of 2-in. sched-40 pipe topped

s e c t i o n of 8-111. sched-40 pipe.

The t o p portion

catches gross leakage while t h e lower portion, holding 0.7 gal, provides s e n s i t i v i t y f o r a l e v e l indicator, LIA-524. This l e v e l i n s t r u ment, and those on t h e l u b r i c a t i n g - o i l supply tanks, provide f o r close inventory of t h e l u b r i c a t i n g o i l .

ORNL Dwg. E-GG-C-41518.

D e t a i l s of t h e tank are shown on

148

Table 5.7.

Lubricating O i l Properties

s t r a i g h t mineral

Nature of base o i l

lO@

Type of base o i l

Paraffinic

Gravity, API

34.8

Viscosity SSU a t 1OOOF, sec

SSU a t 210"F, sec

Flashpoint, "F

322

Firepoint, "F

347

Thermal conductivity, B t u - f t / f t 2 -hr- "F

0.076

Heat capacity, Btu/lb- "F

0.45

Specific gravity

0.85

Equivalent grade Y-12 Plant (UCNC)

Turbine o i l , Code D J

Equivalent commercial grade

Gulfspin 35

149

w i

The rate of o i l l o s s from t h e system i s estimated t o be l e s s than 40 cc/day. 67

I n event t h e o i l catch tank cannot hold t h e accumu-

l a t e d o i l f o r a s a t i s f a c t o r y operating period, a 55-gal s t a i n l e s s s t e e l

drum i s provided i n t h e coolant drain c e l l t o which t h e catch tank can This drum may

be drained through l i n e 720 during reactor shutdown. vent through t h e valve

t o t h e off-gas system through l i n e 525 during

draining. A s m a l l amount of helium gas leaves t h e pump with t h e o i l .

c a p i l l a r y flow r e s t r i c t o r i n t h e gas l i n e downstream of t h e o i l catch tank l i m i t s t h e flow t o less than 0.07 liters/min.

This r e s t r i c t o r i s

preceded by a s i n t e r e d d i s c f i l t e r , and followed by a flow indicator, FIA-524.

Line 524 continues as 1/2-in. pipe through t h e coolant s a l t

drain c e l l t o t h e vent house instrument box.

The gas i s vented through

t h e off-gas system described i n Section 12 following. 5.4.2

Hydraulics The MSFE f u e l - s a l t pump has an 8-in. by 6-in. volute-impeller

combination.

These s i z e s were selected on t h e b a s i s t h a t t h i s provided

a reasonable hydraulic c a p a b i l i t y and were s u f f i c i e n t l y standard so

t h a t e x i s t i n g patterns could be used i n making t h e INOR-8impeller and volute castings. Hydraulic performance data were determined on prototype pumps over a wide range of flow and head conditions and a t several speeds, using 11-in.- and 13-in.-diam impellers.60 A design pump speed of 1150 rpm w a s selected, and t h e impeller diameter w a s established as 11-1/2 i n .

The hydraulic performance data are summarized i n Fig. 524.

It may be noted t h a t a t t h e design speed of 1150 rpm and design flow rate of 1200 gpm t h e developed head i s 48.3 f t .

The pump e f f i c i e n c y

under these conditions i s 80-859. The flow s t a r t u p times f o r t h e primary c i r c u l a t i o n system were estimated using assumed motor accelerating torques (which are nearly constant up t o about 6C$ of speed), and it w a s found that 5@ of f u l l flow i s a t t a i n e d a,fter about 3/4 sec, 759 after 1-1/4 sec, gCY$ after

1-3/4 sec, and 1 0 6 i s reached i n about 3 sec. 79

150

w I

c 0

t, 3 20

200

400

600

e00

IO00

1200

I400

1600

u , FLOW RATE (9pm)

Figure 5.24.

€&draulic Performance of h e 1 FQnp.

151 Coastdown t e s t s determined that about 10 sec a r e required f o r t h e pump motor t o s t o p a f t e r t h e e l e c t r i c a l supply i s interrupted (see ref 80 p 47 and ref 60 p 31). Tests of t h e prototype pump ( w i t h l3-in,-diam impeller) indicated that when t h e l i q u i d l e v e l i n t h e pump w a s lowered t o 4-1/2 i n . below

t h e c e n t e r l i n e of t h e volute, increased amounts of entrained gas were present i n t h e pump discharge.

A t about 5-l/2 i n . below t h e volute

centerline, the-system flow was cut about i n h a l f ; and a t 6-1/2 in., t h e flow was reduced e s s e n t i a l l y t o zero (ref 60, p 31). The prerotation baffle shown i n Fig.

2.3 a t t h e pump i n l e t has

t h e e f f e c t of increasing t h e head a t t h e lower range of flows when operating a t a constant speed (ref 60, p 15). A t t h e most e f f i c i e n t operating conditions, when t h e various l o s s e s

i n t h e impeller and volute a r e a t a minimum, t h e pressure d i s t r i b u t i o n i n t h e volute i s e s s e n t i a l l y uniform, and t h e net r a d i a l force on t h e impeller i s near zero.

When operating a t higher o r lower flow rates

a t t h e same pump speed, t h e volute pressure d i s t r i b u t i o n becomes nonuniform and produces a radial force on the impeller and a r e s u l t i n g d e f l e c t i o n of t h e s h a f t . t h e lower bearing.)

(The impeller i s overhung about 22 i n . below

Tests of t h e prototype MSRE f u e l pump indicated

that a running clearance of 0.025 i n . i n t h e lower labyrinth (see F i g .

5.22) would provide f o r a l l reasonably a n t i c i p a t e d conditions of "off design" operation of t h e pump. 81

5.4.3 Mechanical Design Considerations Design of t h e r o t a r y elements involved computation of s h a f t stresses, deflections, n a t u r a l frequency, bearing l i f e expectancy, flange b o l t i n g requirements, etc.

Design of t h e pump bowl, o r tank, required calcu-

l a t i o n of t h e w a l l thickness, s t r e s s e s , t h e flange requirements, and t h e reinforcement needed a t nozzles, e t c .

5.4.3.1

Volute and Impellers.

The maximum stress i n t h e volute

w i l l be a t shutoff flow conditions a t 1160 rpm and i s estimated t o be

2560 p s i i n bending (ref 66, p 21). The maximum impeller s t r e s s i s a t t h e keyways and i s estimated t o be about 2000 p s i . 5.4.3.2

Shaft.

The impeller horsepower a t r a t e d conditions i s

47.5 hp, based on a pump e f f i c i e n c y of 8 6 and a pump speed of 1150

s 9

152

i i! i

rpm. Assuming a r a d i a l t h r u s t on t h e impeller of 195 l b f (see Section 5.4.2), t h e net axial t h r u s t i s 1130 lbf downward. Some of t h e calcu-

l a t e d s t r e s s e s a r e summarized i n Table 5.8 ( r e f 66, pp 28-30). The maximum s h a f t d e f l e c t i o n a t t h e end of t h e impeller w a s estimated t o be 0.0110 i n . , based on t h e above-mentioned radial t h r u s t ( r e f 66, p 31). The natural frequency of t h e s h a f t w a s predicted t o be a t 2850 rpm, which i s well above t h e design operating speed of 1160 rpm (ref 55, p 33).

5.4.3.3

Bearings.

The SKF catalog data were adjusted f o r MSRE

operating conditions, and a l i f e expectancy of 3OO,OOO t o 5OO,OOO h r f o r t h e pump bearings was predicted ( r e f 66, p 32).

5.4.3.4

Pump Bowl and Nozzles.

Using standard equations from t h e

e w a l l thickness ASME Boiler and Pressure Vessel Code, Section v I I I , t~h ~ 1 ~

required f o r t h e pump-bowl ASME t o r i s p h e r i c a l heads was determined t o be 0.438 i n . , based on an allowable s t r e s s f o r t h e INOR-8of 3600 p s i . The a c t u a l thickness used i s 1/2 i n . ( r e f 66, pp 16-21). A reinforced area i s provided a t t h e 8-in. suction-nozzle opening

t o provide material i n excess of 140$ of t h a t needed t o maintain t h e s t r e s s e s within t h e allowable l i m i t s .

The 1-1/2-in.

sched-40 f u e l -

sampling-enricher nozzle i s a l s o reinforced.

The discharge nozzle

requires an e l l i p t i c a l opening 6 i n . by 7 i n .

The weld f i l l e t i n t h e

knuckle region a t t h i s nozzle i s enlarged t o provide some excess reinforcement. ~

The upper nozzle i s 13.625 i n . I D and does not require

e x t r a reinforcement ( r e f 66, pp 16-21)

b L

The s t r e s s i n t h e pump bowl due t o t h e discharge nozzle reaction w a s determined t o be of l i t t l e concern. I

The s t r e s s i n t h e 23-in.-diam

pump-bowl flange, which i s designed f o r 50 p s i and 300°F, were found

I I

! i

t o be about 13,290 psi, using standard methods of combining s t r e s s e s (ref 66, p 23).

S t r e s s e s i n t h e pump bowl due t o a x i a l loading only 82 were analyzed and found t o be about 5000 p s i .

The bearing-housing upper flange, which i s 27-l/2 i n . . i n diameter and has an assumed operating temperature of l 5 O ? F ,

has calculated

s t r e s s e s of 14,720 p s i (ref 66, p 34).

1 I

i 1

153

Table 5.8.

8 'L

Estimated S t r e s s e s i n MSFE Fuel-Pump Shaft (Psi)

Sheer stress i n lugs of impeller stud

2270

Tensile s t r e s s i n threaded portion of impeller stud

3380

Shear s t r e s s from combined bending and torque at lower bearing

lk20

Torsional shear s t r e s s i n s h a f t a t impeller hub

2325

Shear stress i n keys

1340

Bearing stress a t keys

2680

Shear stress i n shaft a t plane through bottom of bore i n end of shaft

1730

I i

S t r e s s i n s p l i n e a t motor end of shaft

154

5.4.4

Thermal-Stress Design Considerations The MSRE f u e l pump i s subjected t o r e l a t i v e l y high thermal s t r e s s e s

a t operating conditions because nuclear heating can r a i s e t h e temperat u r e of some parts above t h e l225V i n l e t s a l t temperature and because of t h e r e l a t i v e l y large temperature gradient between these p a r t s and, say, t h e t o p flange of t h e pump, which i s only a t about 180%

The

c y c l i c nature of these s t r e s s e s as t h e reactor power l e v e l i s varied requires that they be evaluated on a s t r a i n

- f a t i g u e basis t o determine

t h e extent of r e l i e f that can be expected due t o thermal relaxation i n t h e materials.

z a

The temperature d i s t r i b u t i o n s i n t h e pump bowl were calculated f o r

various conditions of reactor power, s a l t temperature, and cooling-gas flow over t h e outside t o p portion of t h e bowl, using the Generalized 3

Heat Conduction Code (GFR')83

(see a l s o ref 66, p 36).

The thermal-

s t r e s s d i s t r i b u t i o n s were calculated f o r heatup from room temperature t o 12OO0F, power changes from zero t o 10 Mw, and l o s s of cooling gas, using t h e general procedures of Stanek84985 and witt86,87 I n these

studies it w a s assumed t h a t t h e MSRE would undergo one hundred heatup cycles and f i v e hundred power-change cycles.

It w a s f u r t h e r assumed

t h e allowable number of cycles as determined f r o m t h e f a t i g u e curves f o r

INOR-8should exceed t h e anticipated number of cycles by a f a c t o r of a t l e a s t 1.25.

The estimated thermal-fatigue l i f e w a s found t o be adequate,

and t h e calculation indicated that t h e cooling-gas flow r a t e s could be varied over a broad range w i t h small e f f e c t .88

(See a l s o ref 66, p 37)

The sampler-enricher connection l i n e ( l i n e 999) t o t h e f u e l pump bowl i s subjected t o thermal s t r e s s e s due t o t h e axial temperature gradient i n t h e l i n e and a l s o t o t h e pump movements caused by t h e thermal expansions i n t h e primary c i r c u l a t i o n system.

The s t r e s s e s caused by

t h e piping reactions i n t h e sampler l i n e were estimated t o be 7580 p s i i n bending and 1940 p s i i n shear.

These s t r e s s e s were combined w i t h

thepipe reaction s t r e s s e s and compared t o t h e strain-cycle data.

usage f a c t o r of 0.367 w a s obtained, which provides a margin of s a f e t y greater than two when compared t o t h e maximum permissible value of 0.8 f o r t h e usage f a c t o r . 89

L a

155

5.4.5 c a

pump Supports To provide the f l e x i b i l i t y needed i n t h e primary-circulation-system

piping t o maintain t h e s t r e s s e s within t h e allowable limits, it i s necessary that t h e heat exchanger and t h e f u e l - s a l t pump be allowed t o move i n c e r t a i n directions as t h e system i s heated.

(The reactor i s

fixed i n position and an anchor point f o r t h e piping.) Because of t h e degrees of freedom needed, and t h e amount of expected movement, t h e fuel-pump support equipment i s r e l a t i v e l y complicated (see Fig. 5.25).

The f u e l pump i s bolted t o a 2-1/2-in.-thick

plate that i s

mounted on two s e t s of 2-in.-diam r o l l e r s , allowing t h e pump t o move 0

i n a horizontal plane.

(See ORNL Dwgs. E-CC-C-41450 and D-CC-C-41511).

The r o l l e r s t r a v e l on a spring-supported p a r a l l e l - l i n k framework t h a t permits t h e pump t o r i s e v e r t i c a l l y from t h e cold t o t h e hot position. The pump i s restrained from r o t a t i o n about any axis.

Three 3-3/4-in.-

diam by b i n . s t a i n l e s s s t e e l , NaK-filled, double bellows, with o r i f i c e p l a t e s between t h e bellows, a c t t o dampen t h e vibrations induced by t h e pump-shaft r o t a t i o n .

The e n t i r e pump assembly i s c a r r i e d by two 8-in.

horizontal I-beams. 90 When t h e primary system i s brought up t o operating temperature, t h e pump moves about 0.4 i n . horizontally i n t h e north-south d i r e c t i o n , about 0.3 i n . i n t h e east-west direction, and about 0.8 i n . v e r t i c a l l y . 91 A s s t a t e d above, t h e r e i s no r o t a t i o n of t h e pump assembly. * J

5.4.6

Heaters The lower half of t h e pump bowl, a 3-ft-long section of suction

piping and t h e 5-in, 90" bend a t t h e bottom of t h e piping section, I

and t h e overflow tank are a l l heated i n a common furnace, which i s about 51 i n . OD by 66 i n . high. The heating elements are 3/4-in.-diam

s t r a i g h t tubes of 304 s t a i n -

less s t e e l , containing ceramic-positioned resistance heating elements

a t t h e lower ends and having t h e t r a d e name "Firerod" (Watlow Manuf a c t u r i n g Company). Five of t h e rods a r e about 8 f t long overall, with a heated length of about 5 f t , which extend a l l t h e way from t h e terminal boxes t o t h e bottom of t h e basket. a

dis *

about 7 f t long with a heated length of 4 f t .

Nine of t h e rods a r e The heater rods s l i d e

.. .. .I

_. . --. - . .

. ..

. .. .. .. ..

. .

PYgure 5.25.

- ..,. -

mal Rrms support

"._. . .

_____...

....

.. .

157

L, &I

i n t o 1-in.OD 304 s t a i n l e s s s t e e l tubes (0.065 i n . w a l l thickness). (See ORNL Dwg. E-MM-B-51604). The long and s h o r t heater rod a r e arranged, with but one exception, i n t o removable assemblies of one long rod and two short ones.

Each of

these groups of t h r e e rods has a terminal box, o r housing, a t t h e upper end which has a l i f t i n g b a i l , and i n which t h e e l e c t r i c a l power and thermocouple connections are made a t a terminal block.

The nine s h o r t e r

heater rods, c a l l e d t h e "upper portion," a r e connected as one e l e c t r i c a l @ .

c i r c u i t and have a t o t a l heating capacity of 6.5 kw. The f i v e long rods, o r "lower portion," a r e another c i r c u i t and have a capacity of 12 kw. The 51-1/2-in.-OD

1600?E'"

furnace has a 5-in.-thick l a y e r of "Carey-bemp

block i n s u l a t i o n ( P h i l i p Carey Manufacturing Company), covered

w i t h 20-gage

304 s t a i n l e s s s t e e l sheet, The bottom of t h e furnace i s

s i m i l a r l y insulated and covered.

The t o p i n s u l a t i o n i s 2-1/2 i n . of

"Fiberfrax" blanket, "Type XLM," and i s a l s o covered with s t a i n l e s s The t o p of t h e insulated portion of t h e basket i s j u s t

s t e e l sheet.

below t h e bottom of t h e cooling-gas shroud on t h e t o p half of t h e pump bowl.

Gas f o r cooling t h e overflow tank can be supplied through a pipe

a t t h e bottom of t h e furnace although such cooling should not be necessary.

Supports f o r t h e tanks pass through insulated sleeves and

bellows i n t h e bottom a l s o .

(See ORNL Dwg, E - M M - B - ~ ~ ~ o ~ ) .

The furnace i s suspended from t h e fuel-pump support p l a t e and moves a

w i t h t h e pump.

support plate.

The heater rods have c o l l a r s which a l s o r e s t on t h e

The terminal box f o r t h e t h r e e rods i n each group i s connected 8

by t h r e e No. 1 2 wires with i n s u l a t i n g beading t o a w-a, 600-v, 3-pole male plug provided with a l i f t i n g b a i l .

This plug can be pulled upward

by remotely operated t o o l s from t h e female u n i t located on t h e support s t r u c t u r e t o disconnect the heater wiring f o r removal of a heater u n i t o r f o r other maintenance operations.

The power input t o each h e a t e r

c i r c u i t i s manually controlled i n response t o t h e temperature-indicati n g instnunentation. Section 19.

The heater control c i r c u i t s a r e described i n

5.4.7

Fuel-F’ump Overflow Tank Abnormally high s a l t l e v e l s i n the fuel-pump bow1 might r e s u l t from

o v e r f i l l i n g , from temperature excursions while operating, or from unusually high gas entrainment i n t h e c i r c u l a t i n g s a l t .

An overflow pipe

and catch tank prevent t h e s a l t l e v e l from becoming high enough t o allow

salt t o enter the gas and lubricant passages of t h e pump.

5.4.7.1 Overflow Pipe. The overflow l i n e i s a 1-1/2-in. sched-40 INOR-8pipe passing through t h e bottom of t h e pump bowl and extending t o 1-1/2 in. above t h e normal operating l e v e l i n t h e bowl, i.e., elevation of about 840 f t 3 in.

t o an

The pipe extends downward from t h e bowl,

as l i n e 520, and makes t h r e e t u r n s i n a c o i l about 29 in. i n diameter

before entering t h e overflow tank located d i r e c t l y beneath t h e pump bowl (see ORNL Dwg. E-CC-C-56419).

The l i n e i s contained e n t i r e l y

within t h e pump f’urnace and does not require a heating jacket. 5.4.7.2

Overflow Tank.

The overflow tank i s a t o r u s - l i k e v e s s e l

surrounding t h e tapered section of the pump intake pipe.

It i s located

e n t i r e l y within t h e pump furnace, but i s not s t r u c t u r a l l y connected t o it. I

The tank i s 30 in. OD x 18 in. I D x 27-3/4 in. high overall. The tank w a l l thickness i s 1/2 in.,

and t h e annular space between t h e

s t r a i g h t w a l l s of t h e c y l i n d r i c a l portion i s 5 in. wide.

The ends a r e

closed with heads dished t o a 2.5 in. radius, a s shown on ORNL Dwg.

D-CC-C-56418.

The s a l t storage volume i s 5.4 f t3

. The INOR-8v e s s e l

i s designed f o r a pressure of 50 psig a t 14OO0F and i n accordance with t h e ASME Unfired Pressure Vessel Code47 and Cases 1 2 7 0 1 ~ - 5and ~~ 1273N-750 The overflow pipe ( l i n e 520) e n t e r s t h e top of t h e tank and dips t o within l e s s than 1/2 in. of t h e bottom.

A 1/2-in.-deep

dimple i s

pressed i n t h e lower tank head a t t h e e x i t opening of t h e overflow pipe t o permit more complete removal of t h e tank contents. The l i q u i d l e v e l i n t h e tank i s measured by two helium bubbler l i n e s and one reference pressure l i n e i n an arrangement similar t o t h a t used i n t h e pump bowl.

Helium i s supplied through l i n e s 599 and 600

i n 1/4 in.-OD tubing enclosed i n 1/2-in.

sched-40 pipe, t h e tubing

terminating about 1 5 in. from t h e overflow tank with t h e flow continuing

159

160 i n t h e pipe.

As i n t h e pump bowl, t h e helium supply l i n e s have a

surge volume inside and a t t h e t o p of t h e tank i n t h e form of a curved portion of 1-1/2-in.

pipe.

This volume would prevent salt from backing

up i n t o unheated portions of t h e helium supply l i n e s i n event of a pressure surge i n the salt system.

The helium bubbler l i n e s d i p t o

within about 1/2 i n . of t h e bottom of t h e tank. The t o p of t h e overflow tank i s vented t o the off-gas system through A l/b-in.-OD

a 1/2-in. sched-40 pipe connection, l i n e 523.

tubing con-

nection ( l i n e 589) i s made t o l i n e 523 t o provide t h e reference pressure f o r the bubbler l i q u i d - l e v e l indication.

Line 523 continues through

t h e control valve HCV-523, which can be closed t o pressurize t h e overflow tank with helium t o force t h e f u e l s a l t from t h e tank back t o t h e fuel-pump bowl through l i n e 520.

Normally, valve HCV-523 i s open

t o vent the gases from t h e upper portion of t h e overflow tank.

Line

523 joins the off-gas l i n e 521 from t h e fuel-pump bowl upstream of t h e holdup volume i n the reactor c e l l .

5.4.7.3

Tank Support.

beneath t h e fuel-pump bowl.

The overflow tank i s located d i r e c t l y Three 1/2-in.-diam

rods w i t h c l e v i s ends

suspend t h e tank from the pump support during i n i t i a l i n s t a l l a t i o n o r maintenance operations.

Normally, these rods c a r r y no load, and t h e

tank i s supported from below by a f l a t p l a t e mounted on t h e lower end of t h r e e 1-in.-diam 304 stainless s t e e l rods.

The p l a t e r e s t s on t h r e e

spring-mounted balls (Mathews Conveyers Company, Type 501) which allow t h e tank t o move l a t e r a l l y i n any d i r e c t i o n .

While connected t o t h e

f u e l pump only through t h e overflow l i n e , t h e r e may be some displacement forces as t h e pump s h i f t s position with temperature changes.

The

overflow tank remains a t a fixed elevation, t h e f l e x i b i l i t y of t h e overflow pipe accommodating t h e 0.8-in. + e r t i c a l displacement of t h e f u e l pump bowl with temperature changes (see ORNL Dwg. D-CC-C-56420). The t h r e e 1-in.-diam s t a i n l e s s s t e e l support rods mentioned above pass through the pump furnace i n s u l a t i o n through corrugated s t a i n l e s s

s t e e l bellows welded t o t h e rods a t t h e t o p of t h e bellows and w i t h t h e bottom of the bellows welded t o t h e furnace casing.

The clearance

between t h e rods and t h e furnace bottom allows f o r r e l a t i v e movement of t h e tank within t h e furnace, and t h e bellows prevent t h e chimney e f f e c t from inducing a flow of c e l l atmosphere gas through the furnace.

161 *..

(zd

If the overflow tank must store a large amount of fuel salt that

has a relatively high internal-heat-generation rate, it may be necessary

to cool the overflow tank. A 1-1/2-in. connection is provided at the furnace bottom through which cell atmosphere gas can be supplied from the component cooling system. A 3-in.-diam stainless steel bellows in this connection provides a spring-loading on a sliding metal-to-metal flat-plate joint to allow relative movement of the furnace and the gas supply line connection (see ORNL E-CC-C-56419). s

162

5.5 Fuel Heat Exchanger The f u e l heat exchanger i s used t o t r a n s f e r heat from t h e f u e l

salt t o t h e coolant s a l t .

The location of t h e exchanger i n t h e r e a c t o r

containment vessel i s shown i n Figs. 4.4 and 4.5.

The r e l a t i o n s h i p

of t h e heat exchanger i n t h e primary system flowsheet i s discussed i n t h e preceding Section 5.2 and shown i n Fig. 4.6.

-The physical prop-

e r t i e s of t h e f u e l and coolant salts a r e summarized i n Table 2.1. With t h e e z e p t i o n of t h e furnace-brazing of t h e tube-to-tubesheet

j o i n t s , t h e heat exchanger was f a b r i c a t e d i n t h e machine shops of t h e Y-12 Plant.

The furnace-brazing was performed a t t h e Wall Colmonoy

5.5.1

A l l t h i s work was covered by ORNL s p e c i f i c a t i o n s . 92 93,94

Company ( D e t r o i t ) . Description

The heat exchanger i s a horizontal, s h e l l and U-tube type, with t h e f u e l s a l t c i r c u l a t i n g i n the s h e l l and t h e coolant s a l t i n t h e tubes (see Figs.

2.4 and 5.27).

It i s of all-welded construction and

i s fabricated of INOR-8 throughout, except f o r t h e back-braze a l l o y used

i n t h e tubesheet j o i n t s . given i n Table 5.9.

The o v e r a l l dimensions and design data a r e

(See ORNL Dwg. D-EE-Z-40850).

The s h e l l i s m i 6 i n . OD and about 8 f t 3 i n . -long, including t h e 8-3/4-in. -long coolant s a l t header and t h e ASKE flanged and dished heads a t t h e ends (see ORNL Dwg. D-EE-A-40874).

The s h e l l i s 1/2 i n .

t h i c k i n both t h e c y l i n d r i c a l portion and t h e heads.

The f u e l e n t e r s

a t t h e U-bend end of t h e s h e l l through a 5-in. sched-40 nozzle, near t h e

t o p of t h e dished head.

A l/b-in.-thick

d i r e c t impingement on t h e tubes.

b a f f l e on t h e i n s i d e prevents

The f u e l s a l t leaves through a 7-in. x

-1

5 i n . reducer nozzle a t t h e bottom of t h e s h e l l a t t h e tube-sheet end. To prevent v i b r a t i o n a t t h e higher flow r a t e s due t o t h e clearance between t h e tubes and t h e b a f f l e plates, INOR-8rods, 0.166-in.

x 1/4-in.,

are inserted, o r "laced", between t h e tubes.

The rods a r e used a t each b a f f l e p l a t e , with one s e t i n s e r t e d i n t h e horizontal d i r e c t i o n and t h e other a t an angle of 60".

The rods

f i t snugly i n t o t h e spaces between t h e tubes and e f f e c t i v e l y r e s t r a i n

each tube from transverse motion r e l a t i v e t o t h e o t h e r s . rods a r e t a c k welded i n place a t each end.

The horizontal

The inclined rods a r e t a c k

welded a t l e a s t on one end, and on both ends where accessible.

The

Y .

6, "

€

' I

163

164 Table 5.9.

Design Data f o r Primary Heat Exchanger

Construction material

INOR-8

Heat load, MW

Shell-side f l u i d Tube - side f l u i d

Fuel salt Coolant s a l t

Layout

25s cut, crossbaffled s h e l l with U-tubes

Baffle pitch, i n . Tube pitch, i n .

12 0.775 triangular

Active shell length, f t Overall shell length, f t

4 ~8 16

Shell diameter, in. Shell thickness, i n .

1/2

Average tube length, f t Number of U-tubes

159 1/2 OD; 0.042 wall -254 1-112 6.1 1300

Tube size, i n . Effective heat transfer surface, f t2 Tubesheet thickness, i n . Fuel salt holdup, f t 3 s h e l l side, "F tube side, "F

Design temperature: Design pressure :

1300

s h e l l side, psig tube side, psig

Allowable working pressure:*

shell side, psig tube side, psig s h e l l side, psig tube side, psig

Hydrostatic t e s t pres sure : Terminal temperature:

55 90

800

1335 1225 i n l e t ; 1175 outlet 1025 i n l e t ; 1100 outlet

f u e l salt, "F coolant, "F

Effective log mean temperature difference,

75 125

O F

133

s h e l l side, psi tube side, psi

Nozzles : shell, i n . (sched-40) tube, i n . (sched-40) Fuel-salt flow rate, gpm

5 5 1200 (2.67 cfs)

Coolant-salt flow rate, gpm

850 (1.85 cfs)

Pressure drop:

*Based on actual thicknesses of materials and stresses allowed by

ASME Code.

165 rods a r e l e f t out a t locations where neither end could be fastened. For t h i s reason, rods a r e used i n the horizontal d i r e c t i o n only a t t h e

stub b a f f l e p l a t e and a t t h e lower portion of t h e b a f f l e a t t h e f u e l i n l e t end of t h e exchanger.

The rods a t these two locations a r e

O.17l-in. x 1/4-in. acd 0.174-in. x 1/4-in.,

respectively.

The tubes

are a l s o r e s t r a i n e d a t t h e U-end of t h e tube bundle by rods i n s e r t e d i n two d i r e c t i o n s through t h e f i v e outermost rows of tubes,

Two 1-1/2-

in,-wide INOR bands a r e used t o hold t h e rods i n position.

One of t h e

bands, which i s s l o t t e d t o accept t h e ends of t h e rods, i s i n s e r t e d horizontally i n t o t h e tube bundle.

The other band i s wrapped around

t h e outside and has t h e ends of t h e rods t a c k welded t o it.

See ORNL

.* S i x 25% cut b a f f l e s of 1/4-in.

Dwgs 10329-R-001-E and 10329-R-002-E

p l a t e , spaced a t 12-in. i n t e r v a l s , d i r e c t t h e f u e l - s a l t flow across t h e tube bundle (see ORNL Dwg. D-EE-A-40866).

A barrier plate, similar

t o t h e b a f f l e p l a t e s but w i t h no cutaway segment, i s located 1-7/8 i n . from t h e tubesheet t o provide a more o r l e s s stagnant l a y e r of f u e l s a l t and reduce t h e temperature difference across t h e tubesheet.

The

b a f f l e s and t h e b a r r i e r p l a t e a r e held i n position by spacer rods, screwed and tack-welded together, t o t h e tubesheet, and t o each b a f f l e . A divider separates the entering and leaving coolant-salt streams

i n t h e coolant header.

It i s f a b r i c a t e d of 1/2-in. p l a t e and extends

from t h e tubesheet t o t h e dished head a maximum distance of about 12 i n . ; it i s w e l d e d o n l y t o t h e dished head.

It is positioned by guide strips

on t h e s h e l l w a l l , and a groove i n t h e edge f i t s over a 1/4-in. pointed, horizontal projection on t h e tubesheet.

T h i s arrangement provides a

labyrinth-type s e a l between t h e channels without s t i f f e n i n g t h e tubesheet. The divider prevents use of a horizontal row of tubes a t t h e exact center of t h e tubesheet.

Also, i n arranging t h e U-tube bundle i n t o a

configuration that could be assembled, it w a s necessary t o leave out t h e nine tubes on t h e horizontal row immediately above and below t h e center.

These holes are not d r i l l e d i n t h e tubesheet.

To maintain fuel-

s a l t v e l o c i t y d i s t r i b u t i o n s i n t h e s h e l l and a l s o t o keep t h e f u e l - s a l t inventory t o EL minimum, s o l i d rods of INOR-~,1/2 i n . i n diameter, a r e used a t these locations i n t h e tube bundle. *Development drawing numbers.

-t

166 There a r e 159 tubes, 1/2 i n . OD by 0.042 i n . w a l l thickness,

affording a t o t a l heat t r a n s f e r surface of ~ 2 5 4f t 2 . arranged on a 0.775-in.

The tubes are

equilaterial triangular pitch.

sheet i s 1-1/2 i n . t h i c k .

The tube-

The holes through t h e tubesheet had

trepanned grooves on both s i d e s of t h e sheet. The grooves on the coolant-salt s i d e were t o permit t h e tube-totubesheet weldsg5 t o be made between t h e tube and a l i p of about equal

w a l l thickness.

The groove has an o v e r a l l depth of 0.090 i n . , i s 0.068

i n . wide, and leaves a l i p of 0.042 i n . (see Fig. 5.28).

The tubes

were expanded a t t h e t i p end i n t o t h e holes before welding; a f t e r welding, t h e tube openings were reamed t o t h e inside diameter of t h e tubes. 96 The tubesheet holes had trepanned grooves on t h e f u e l - s a l t side t o permit back-brazing of t h e j o i n t s .

These grooves were 0.100 i n . deep, 0.100 i n . wide, and with a l i p of 0.025 i n . ( r e f 94) (see Fig. 5.28). T h i s groove held an 8% gold

brazing.g7

- 18$ nickel brazing r i n g p r i o r t o furnace-

The brazing operation consisted of holding t h e assembly

between 1850 and 1885°F f o r 60 min i n a hydrogen atmosphere having a dewpoint temperature below -80”F,94 and a flow r a t e of 345 ft3/hr. Both t h e heating r a t e and t h e cooling r a t e f o r t h e brazing cycle were limited t o 300”F/hr.

Three 3/32-in.-diam

equally spaced holes were

d r i l l e d from t h e bottom of t h e braze-ring trepan t o communicate with t h e 0.0015 t o 0.003-in. annular space between t h e tube and t h e tube-

sheet hole, t o permit t h e braze metal t o flow i n t o t h i s space during

t h e furnace brazing.98

An excess of t h e braze f i l l e r metal was

provided t o assure complete f i l l i n g of t h e void and enough t o form a f i l l e t between t h e tube w a l l and t h e f u l l thickness of t h e trepan l i p . V i s u a l examination of these f i l l e t s a f t e r brazing gave an indication that each braze void was completely f i l l e d . 9 8

There was no apparent

d i s t o r t i o n of t h e tubes, and t h e metal was b r i g h t and clean.

Ultra-

sonic inspection by use of a Lamb-wave probe, w i t h a 3/32-in.-diam flat-bottomed hole as a standard, indicated some porosity but no open channels i n t h e brazed j o i n t s .

After f a b r i c a t i o n t h e u n i t w a s h y d r o s t a t i c a l l y t e s t e d t o 1335 psig on t h e tube s i d e and 800 psig on t h e s h e l l s i d e .

The s h e l l s i d e w a s

. 167

Unclassified ORNL DWG 64-8820

0.0015

- 0.003 i n .

e3.

* *

i 0.042 in.

i -+ j 4 t-'

Figure 5.28.

0.068 in.

Tube to Tube-Sheet J o i n t in MSRE Primary Heat Exchanger.

168 pressurized f i r s t and maintained a t 800 p s i while t h e tube side was pressure t e s t e d . 92'99

b.I

A helium mass spectrometer leak t e s t w a s applied, with t h e

shell-side pressure l e s s than 5 microns abs and t h e tube-side pressurized w i t h h e l i u m t o 100 psig.

There were no leaks.

The heat exchanger is i n s t a l l e d horizontally, pitching toward t h e f u e l - s a l t o u t l e t a t a slope of about 3 " . Each U-tube i s oriented so that t h e coolant salt w i l l a l s o drain.

Section 5.5.3.

The supports a r e described i n

The u n i t weighs about 2060 l b when empty and 3500 lb

when f i l l e d with both f u e l and coolant s a l t s .

The f u e l - s a l t holdup i s

~ 6 . 1ft3, and t h e coolant-salt holdup i s about 3.7 f t 3 . The s h e l l i s surrounded by e l e c t r i c heating u n i t s of about 30 kw t o t a l capacity, as described i n Section 5.5.4. I n normal operation, t h e coolant-salt pressure w i l l be maintained

a t a s l i g h t l y higher value than t h e f u e l - s a l t pressure so t h a t coolant salt w i l l flow i n t o t h e f u e l system i f a l e a k develops. 5.5.2

Design Considerations The heat exchanger was designed f o r low holdup of s a l t s , s i m p l i c i t y

of construction, and moderately high performance.

The space l i m i t a t i o n s

within t h e containment c e l l required a f a i r l y compact u n i t .

A U-tube

configuration best s a t i s f i e d t h i s requirement and a l s o minimized t h e thermal-expansion problems i n t h e exchanger. From t h e heat t r a n s f e r standpoint, it w a s b e t t e r t o pass t h e f u e l s a l t through t h e s h e l l and t h e coolant salt through t h e tubes, since

t h e f u e l - s a l t volume flow r a t e is l a r g e r .

The s h e l l s i d e a l s o presents

l e s s opportunity f o r r e t e n t i o n of gas pockets during f i l l i n g operations. A f u r t h e r consideration i n t h i s respect w a s t h a t t h e f u e l - s a l t system

operates a t a s l i g h t l y lower pressure than t h e coolant-salt system and t h e r e w a s a small savings i n t h e required s h e l l thickness. 5.5.2.1

Heat Transfer.

The behavior of molten salts as heat

t r a n s f e r f l u i d s had been investigated p r i o r t o design of t h e E R E . 100 There w a s good agreement between measured values of t h e tube-side c o e f f i c i e n t s by Amos e t

ai.ioo and calculated values based on t h e

generalized formula of Sieder and Tate.

The heat t r a n s f e r design c

conditions a r e given i n Table 5.9, and t h e physical properties of the f u e l and coolant salts a r e given i n Table 2.1.

r, .

169 The mean A t f o r a t r u e countercurrent heat exchanger would be

137V. A correction f a c t o r of 0.96 was applied t o include t h e e f f e c t s of a single-pass s h e l l , which reduced t h i s value t o t h e 1339 shown i n Table 5.9 (see Section V I , Ref 18). Film coefficier;ts were assumed t o be constant on both s i d e s of t h e tube w a l l .

The v e l o c i t y i n t h e tubes i s about 1 2 , l f p s and t h e

Reynold's modulus about 9060, giving a f i l m c o e f f i c i e n t of about 4900 Btu/hr-f@-OF

.* The pressure drop i n t h e tubes w a s estimated t o be

about 2.2 p s i / f t . *

(See Section V I , Ref 18)

The f i l m c o e f f i c i e n t on t h e s h e l l i s estimated t o be 3200 B t u / f t 2 - h r - 9 f o r a Reynold's modulus of 13,000.

The o v e r a l l heat

t r a n s f e r c o e f f i c i e n t i s about 1100 Btu/hr-ft2-OF.

The resistance t o

heat flow i s about equally divided between t h e tube-side f i l m , t h e tube w a l l , and t h e s h e l l - s i d e f i l m .

The o v e r a l l c o e f f i c i e n t makes a n

allowance of about 1.0% f o r possible "scale" deposits on t h e tubes.

I n estimating t h e o v e r a l l capacity, o r r a t i n g , of t h e heat exchanger, t h e a c t i v e length of t h e tubes w a s taken as t h e s t r a i g h t portion between t h e thermal b a r r i e r p l a t e and t h e last b a f f l e , since experience i n d i c a t e s t h a t t h e heat t r a n s f e r c o e f f i c i e n t i n t h e bends of U-tube-type exchangers i s considerably l e s s than i n t h e s t r a i g h t sections.

On t h i s b a s i s t h e e f f e c t i v e area i s 259 f t 2 , which i s about

8$ more than t h e calculated requirement f o r 10-Mw capacity.

This

extra amount, plus the "dirty tube" allowance, affords a margin of about 2fl0 on t h e conservative s i d e . 5.5.2.2 c

Pressure Drops.

The estimated t o t a l pressure drop on

t h e s h e l l s i d e was estimated t o be 22 p s i a t 1200 gpm.lo2

Preliminary

t e s t i n g of t h e complete exchanger indicated a pressure drop of almost twice t h i s mount, primarily due t o t h e i n l e t and o u t l e t l o s s e s .

The

s h e l l was lengthened by 1-in. t o make room f o r an i n l e t impingement b a f f l e , four tubes were removed (leaving a t o t a l of 254), and t h e baffle s t a y rods which p a r t i a l l y blocked t h e f u e l - s a l t exkt nozzle opening were eliminated. Subsequent t e s t i n g indicated a t o t a l pressure drop a t 1200 gpm of 25-30 p s i . 177 'AThese values, given i n Ref 18, a r e based on a coolant-salt c i r c u l a t i o n r a t e of 830 gpm r a t h e r than t h e r a t e d conditions of 850 gpm. The g r e a t e r v e l o c i t y afforded by t h e l a t t e r w i l l increase t h e calculated values of t h e film c o e f f i c i e c t s end t h e o v e r a l l c o e f f i c i e n t s l i g h t l y . 4

170 The estimated tube-side pressure drop was 29 p s i a t 850 gpm. Tests on t h e 254-tube exchanger indicated a value of about 30 p s i . 177 5.5.2.3

The thickness of t h e s h e l l w a s determined

Stresses.

from t h e formulae of t h e ASME Unfired Pressure Vessel Code, Section

V I 1 1 47

The heat exchanger w a s designed f o r pressures of 55 psig on t h e s h e l l side and 90 psig on t h e tube s i d e a t 1300°F (see Section V, p 2, Ref. 18).

Except f o r thermal s t r e s s e s i n t h e tubes, t h e s t r e s s e s

were limited t o 2750 p s i .

Taking i n t o consideration t h e a c t u a l thick-

nesses of material used and t h e higher s t r e s s e s permitted by t h e Code, t h e allowable working pressures a r e 75 psig f o r t h e s h e l l s i d e and 125 psig f o r t h e tube s i d e a t 130OoF.

The tube w a l l thickness w a s based more on t h e welding requirements than on pressure-stress considerations.

Experience had indicated that

w a l l thicknesses of l e s s than 0.04 i n . had more of a tendency t o crack a t t h e tube welds; therefore t h e tube w a l l thickness w a s more o r l e s s a r b i t r a r i l y f i x e d at 0.042 i n .

T h i s provides considerably more strength

than i s needed t o contain t h e design pressure.

The s t r e s s e s developed

i n the tubes due t o one l e g of t h e U being h o t t e r than t h e other a r e not excessive and a r e l a r g e l y self-adjusting.

The thermal s t r e s s due

t o t h e temperature difference across t h e tube wall i s estimated t o be a maximum of 10,000 p s i and i s g r e a t e s t i n t h e U-bends where t h e fuel salt is hottest.

Under normal operating conditions t h e tube w a l l

i n t h i s region w i l l not exceed ll5OOF.

The s t r e s s f o r 0.1 CRU i s about

10,000 p s i a t l l 5 O O F so there should be no concern f o r t h e l i f e of t h e

tubes unless t h e reactor i s operated through a l a r g e number of cycles between zero and f u l l power a t higher temperatures. The thickness of t h e tubesheet was determined by standard TEMA formulae1o3 t o be 1.5 i n . f o r a pressure of 55 p s i across t h e sheet and a pressure s t r e s s of 2750 p s i .

This pressure d i f f e r e n t i a l assumes

that t h e coolant salt i s a t 65 psig and t h e f u e l salt i s a t 10 psig (no flow condition).

The thermal b a r r i e r p l a t e on t h e s h e l l s i d e i s

estimated t o l i m i t t h e temperature difference across t h e tubesheet t o

less than 2 0 T (see Section V, p 18 of Ref 18). The baffle on t h e coolant-salt s i d e i s kept separate from t h e tubesheet i n order t o avoid l a r g e localized stresses.

171

5.5.2.4

Vibration.

Development t e s t i n g of t h e heat exchanger

as constructed t o t h e o r i g i n a l design indicated excessive vibration of t h e tubes a t t h e rated flow r a t e .

The design was then modified t o

include an impingement baffle on t h e f u e l - s a l t i n l e t and i n s t a l l a t i o n

of "lacing" rods t o r e s t r a i n l a t e r a l movement of individual tubes. Subsequent t e s t i n g showed that t h e noise due t o t h e tube vibration 11 had been eliminated.

5.5.3 ?

supports The heat exchanger i s connected t o t h e reactor vessel and t h e pump

by short and s t i f f piping, s o one of t h e primary considerations i n designing t h e supports f o r t h e heat exchanger was that it must be allowed t o move with but l i t t l e r e s t r a i n t when t h e system i s heated and cooled. c

The coolant salt l i n e s attached t o t h e heat exchanger have s u f f i c i e n t f l e x i b i l i t y i n looping around t h e reactor c e l l space t o s u b s t a n t i a l l y reduce t h e reactions on t h e heat exchanger nozzles due t o thermal expansion i n these l i n e s . The heat exchanger r e s t s on two INOR-8saddle supports t h a t a r e

welded t o t h e s h e l l about 46 i n . apart.

The INOR-8 l e g s on which t h e

saddles a r e welded a r e of d i f f e r e n t heights t o give t h e s h e l l a p i t c h of about 3" toward t h e f u e l - s a l t o u t l e t end.

The l e g s are bolted t o

a carbon s t e e l frame, about 30 i n . wide and 10 f t 8 i n . long, fabricated of 6-in. I-beams.

This frame i s i n s t a l l e d horizontally and r e s t s on

four 3-in.-diam r o l l e r s (see ORNL Dwg. E-EE-D-41492).

The support

bracket f o r each of t h e r o l l e r s has a 2-15/16-in.-diam

pin i n s e r t e d

i n a t h r u s t bearing, which c a r r i e s t h e v e r t i c a l load and permits t h e r o l l e r s t o be self-aligning,

The t h r u s t bearings a r e mounted on t o p

of t h e Grinnel* spring hanger assemblies having adjustable spring tension, load i n d i c a t o r and scale.

The s p e c i a l tension adjustment b o l t can

be turned by use of remotely operated t o o l s from above (see ORNL Dwg-

D-DD-D-41491). The spring hanger assemblies r e s t on a fixed support s t r u c t u r e of 8-in. I-beams. (See Section X I , Ref 18). The arrangement of supports allows t h e heat exchanger t o move horizontally i n a north-south d i r e c t i o n on t h e r o l l e r s , and t o move v e r t i c a l l y and r o t a t e against t h e spring actions.

A small amount of .

172 east-west horizontal t r a n s l a t i o n (very l i t t l e should be requkred) can be accommodated by t h e frame s l i p p i n g l a t e r a l l y on t h e r o l l e r s t o t h e "least-loaded" position. Piping reactions on t h e heat exchanger nozzles a r e shown on ORNL Dwg. D-EE-Z-40852 and a r e discussed i n Section 5.6.

5.5.4

Heaters The salts i n t h e primary heat exchanger a r e kept molten by

e l e c t r i c resistance heaters i n s t a l l e d outside t h e s h e l l .

The

heater u n i t s a r e arranged i n t h r e e sections and a r e e s s e n t i a l l y i d e n t i c a l t o t h e removable heaters applied t o t h e 5-in. s t r a i g h t sections of s a l t piping (see Section 5.6.6.2) a r e designed f o r t h e 16-in. OD s h e l l .

except that they

The heaters a r e connected

i n t h r e e separate c i r c u i t s , each three-phase, 2 0 8 - ~ , 10-kw, t o give a t o t a l heat input capacity of 30-kw.

The thermal i n s u l a t i o n

i s similar t o t h a t used on t h e pipe sections.

(See Mirror I n s u l a t i o n

company Dwg ~-108-~).

173

5.6 Primary Circulating System Piping, Supports, Heaters, Insulation, Freeze Flanges and Freeze Valves.

5.6.1

Piping With t h e exception of a t r a n s i t i o n piece a t t h e pump suction, a l l

t h e primary c i r c u l a t i n g system piping i s fabricated of 5-in. sched

40 seamless INOR-8pipe. Flanges a r e provided between t h e three major pieces of e q u i p e n t i n t h e loop t o f a c i l i t a t e t h e i r removal and replacement. These "freeze" flanges a r e described subsequently i n Section 5.6.4. Forged elbows a r e used i n t h e piping where space did not permit use of longer radius bends.

The system includes on& 90" bend, one bend

of about 3O", three 90" elbows, one 57" elbow and one 34" elbow.

A l l piping i n t h e c i r c u l a t i n g system pitches downward a t 3" t o cause drainage towards t h e reactor.

(The d r a i n l i n e from t h e bottom of t h e

reactor, l i n e 103, pitches a t about 3" t o drain toward t h e f u e l d r a i n

tanks. ) The piping between the reactor discharge nozzle and t h e f u e l - s a l t pump suction nozzle, l i n e 100, i s welded t o t h e reactor nozzle and extends almost horizontally, with a s l i g h t bend, approximately 6 f t t o a freeze flange, FF-100; from t h i s flange it bends s l i g h t l y i n t h e horizontal plane and t u r n s upwards 90", terminating i n t h e pump nozzle t r a n s i t i o n piece. T h i s s p e c i a l conical section i s approximately 32 i n . long and r o l l e d from

3/8-in. INOR-8 plate.

It i s required t o make t h e t r a n s i t i o n from t h e

5-in. pipe i n l i n e 100 t o t h e 8-in. nozzle on t h e pump bowl. c

x 6-in. eccentric reducer i s used a t t h e pump discharge nozzle. ORNL Dwgs E-GG-B-40700,

A 5-in.

See

E-GG-B-40701 and E-GG-E-41866.

Line 101 i s welded t o t h e pump discharge nozzle and extends horizontally about 3-1/2 f t where it makes a 90" bend i n t h e horizontal plane and joins t h e freeze flange FF-101, which i s close-coupled t o t h e heat exchanger i n l e t nozzle. Line 102 drops v e r t i c a l l y from t h e o u t l e t a t t h e underside of t h e heat exchanger a distance of about 5-1/2 f t t o a 90" elbow and then runs horizontally through a sweeping 90" bend t o t h e freeze flange, FF-102; from t h i s flange it continces horizontally througH a s l i g h t bend t o t h e reactor i n l e t nozzle.

174 "he pump bowl overflow l i n e i s described i n Section 5.4.7.1

and t h e

drain pipe, l i n e 103, i s discussed i n Section 6. 5.6.2

Piping S t r e s s e s and F l e x i b i l i t y Analysis

The reactor v e s s e l i s suspended from t h e s t a t i o n a r y top cover of t h e thermal s h i e l d and i s thus fixed i n p o s i t i o n and t h e anchor point f o r t h e piping i n t h e primary c i r c u l a t i n g system.

The c i r c u l a t i n g loop

i s r a t h e r compact, with short r e l a t i v e l y s t i f f lengths of 5-in. pipe connecting t h e equipment.

To avoid use of bellows-type expansion j o i n t s t o

r e l i e v e s t r e s s e s due t o thermal expansion, t h e heat exchanger and f u e l

pmp supports were designed t o allow r e l a t i v e l y f r e e movement. The f u e l pump mount allows t h e pump t o move on r o l l e r s i n t h e horizontal plane and a p a r a l l e l - l i n k framework, supported on springs, permits v e r t i c a l movement f r o m t h e cold t o t h e hot p o s i t i o n (see Section 5.4.5). The pump bowl i s thus r e s t r a i n e d from r o t a t i o n about any axis. The heat exchanger supports permit it t o move horizontally i n two d i r e c t i o n s on r o l l e r s and t o move v e r t i c a l l y and r o t a t e about i t s longit u d i n d axis by acting against t h e spring supports, as described i n Section 5.5.3. The sustained s t r e s s e s i n t h e piping, L e . ,

those due t o i n t e r n a l

pressure and weight of the equipment and contents, were estimated using conventional relationships4'

and found t o be l e s s than t h e allowable o 16 s t r e s s of 3,500 p s i a t 1300 F. F l e x i b i l i t y analyses were made on t h e primary c i r c u l a t i n g system

piping using t h e IBM Modification of Pipe S t r e s s Program, SHARE,

No. GS 3812."

Estimates were based on a r e a c t o r power l e v e l of 10 Mw

when t h e primaxy piping i s between 1175OF and 1225'F, piping i s between 1025'F

t h e coolant-salt

and llOO°F, and t h e r e a c t o r v e s s e l and heat ex-

changer axe a t about 1200OF.

For every anticipated r e a c t o r operating

condition t h e maximum s t r e s s e s were calculated t o be w e l l below t h e a l lowable s t r e s s range of 32,125 p s i ,

* as determined from t h e Code of Pressure

*See p 96, r e f 106. Based on SA = f(1.25 Sc + 0.25 Sh), where SA i s allowable s t r e s s range, p s i ; f i s s t r e s s reduction f a c t o r , taken t o be u n i t y f o r l e s s than 7,000 full temperature cycles over expected l i f e ; Sc i s allowable s t r e s s i n cold condition, taken as 25,000 p s i (see r e f 16); and % i s allowable s t r e s s i n hot condition, taken as 3,500 p s i a t l3OOOF (see r e f 16).

175 Piping, ASA B 3 l . l . lo' The maximum s t r e s s i n t h e piping system was estimated t o be 7,700 psi, which occurs a t t h e coolant-salt i n l e t nozzle t o t h e heat exchanger. 91 Calculated movements of t h e pump from t h e cold t o t h e hot condition

a t 10 mw were:

(N-S) = 0.401 i n . ; Ay (E-W) = 0.335 i n . ; and Az ( v e r t )

= 0.826 i n . 91

5.6.3

supports There a r e t e n supports on major piping inside the reactor c e l l ,

t h r e e on t h e f u e l - s a l t piping and t h e remainder on t h e coolant-salt lines.

Rigid supports can be used a t one location i n t h e f u e l - s a l t

system and a t two places i n t h e coolant-salt piping; a t a l l other locations t h e piping r e s t s on spring-loaded mountings.

The supports

f o r d r a i n l i n e lo3 a r e described with t h e drain tank c e l l salt t r a n s f e r l i n e supports, Section

6.28.

The spring supports a r e Bergen Pipe Support Corporation (New York, N.Y.)

u n i t s , Model V S - p ,

i n s i z e s 3,

5, 6, 7 and 8.

The spring s e t t i n g

i n each i s variable t o a d j u s t t h e support t o t h e piping load, as will be discussed subsequently.

A short column of 3-in. sched 40 pipe r e s t s on

t h e spring support and c a r r i e s a 10-in. x 10-in. x 1/2-in.-thick p l a t e a t t h e top.

Nine 1-in.-diam s t e e l balls (Mathews Type 101) are

mounted on t o p of t h e p l a t e .

steel

A similar horizontal p l a t e , which r e s t s on

t o p of t h e balls, i s welded t o a bracket arrangement extending through t h e thermal i n s u l a t i o n a t t h e bottom of t h e pipe.

These p l a t e s , w i t h t h e ex-

ception of the p l a t e a t support S-2, a r e i n s t s l l e d p a r a l l e l w i t h the slope 2

of t h e pipe a t each location.

The supporting arrangement thus allows freedom

of movement of t h e piping i n t h e horizontal plane, provides a variable spring

force i n t h e v e r t i c a l d i r e c t i o n , and by supporting from below, allows t h e piping t o be removed f o r maintenance operations without disturbing t h e support s t r u c t u r e . (See ORNL Dwgs E-GG-E-41886)

The support loads and the movements of t h e piping were estimated using t h e methods given t h e Bergen Pipe Support Corporation Catalog No.

59.1°7

These values, f o r both the f u e l - s a l t and t h e coolant-salt piping

inside t h e reactor c e l l a r e summarized i n Table 5.10. The following weights were assumed i n making t h e estimates: 107

176 5-in. sched 40 INOR-8 pipe

15 lb/ft

Weight of s a l t i n pipe*

Thermal i n s u l a t i o n

30 5

E l e c t r i c heaters Support frame

Freeze flange and clamp Clamp frame

290 212

The movements l i s t e d i n Table 5.10 a r e f o r uniform heatup of t h e system t o 1300OF. The values f o r a c t u a l operation may d i f f e r s l i g h t l y . I n most instances t h e springs w i l l exert upward forces on t h e piping when t h e system i s cold.

These forces approximately equal the weight of t h e

salt i n the effected portion of t h e system. A description of t h e forces on a t y p i c a l support,

S-3 on l i n e

201 i n t h e coolant-salt piping, will explain t h e operation.

The spring i n

t h i s support i s i n i t i a l l y compressed 1-11/16 i n . and a plug i s i n s e r t e d t o

maintain the- spring i n t h i s position.

The spring scale pointer w i l l read

608 lbs. The support i s then placed i n position and t h e empty pipe load of 397 l b s i s r e s t e d on it. Since t h e pipe will expand 1/4 i n . upwards when heated, a second spacer 1-7/16 i n . long i s s u b s t i t u t e d f o r t h e first one. The spring w i l l then e x e r t t h e f u l l 608 l b s force against t h e pipe, with a r e s u l t a n t upwards force on t h e pipe of 211 pounds.

As t h e system

i s heated, but s t i l l empty of salt, t h e pipe expands upwards and t h e spring

a l s o expands t h e 1/4 i n . maximum t r a v e l allowed by t h e 1-7/16-in. s t o p spacer piece.

travel

The spring scale w i l l then read 581 l b s , but no force

greater than t h e 397 l b s weight of t h e pipe can be exerted because of t h e t r a v e l stop.

When t h e system i s f i l l e d with salt, an additional 184

l b s must be c a r r i e d by t h e support; t h e t o t a l piping load of 581 l b s i s thus counter balanced by t h e spring s e t t i n g of 581 l b s . 107

The variable spring support, S-10, f o r l i n e 101 i s compressed when t h e system i s cold i n order f o r it t o give f u l l support after t h e pipe has moved 3/8 i n . upwards t o t h e hot position.

The cold spring

s e t t i n g i s 188 l b s and it supports a weight of 180 l b s a t operating conditions. a

*In estimating t h e weight of t h e salt i n a pipe, a density of 150 lbs/ft3 was used i n both f u e l and coolant-salt systems, since t h e difference i n t h e weights amounted t o but

4 l b s / f t of pipe. c 1

T a b l e 5.10

tjupport

No.

V a r i a b l e S p r i n g S u p p o r t s f o r F u e l and C o o l a n t - S a l t P i p i n g I n s i d e Reactor C e l l

I Line I s u p p o r t Load 1 s u p p o r t Load I No.

(Pipe Full)

( P i p e Empty)

s-1

100

s -2

102

s-3

s-4

Hanger Type and S i z e No.

1/8" Down

234 l b s

316 l b s

3/8" Down

201

397 l b s

581 l b s

1/4" Up

201

442 l b s

503 l b s

1/8" Up

Bergen VS3F Size 5 Bergen V S F Size 8 Bergen VSY Size 7

201

347 l b s

468 l b s

<o .06" up

R i g i d Support

Rigid Support

200

424 l b s

683 l b s

200

410 l b s

669 l b s

Bergen VS3F Size 6 Bergen VS3F Size 8 Bergen VSY Size 8

200

301 l b s

389 l b s

Rigid Support

101

lo3 l b s

140 l b s

Bergen BS3F Size 3

200

s-10

Pipe Movement

Spring Setting

Remarks Top of s u p p o r t t o be 1/8" No S p r i n g below bottom of pipe I n s e r t s t o p t o l i m i t down234 Ibs ward t r a v e l t o 318 i n . I n s e r t s t o p t o l i m i t upward 608 Ibs t r a v e l t o 1/4 i n . I n s e r t s t o p t o l i m i t upward 514 Ibs t r a v e l t o 118 i n . . No Top of s u p p o r t t o be f l u s h w i t h bottom of d u e I n s e r t s t o p t o l i m i t upward 394 1bs r a v e l t o 318 i n . T 7 ~ c ,1-1 I n s e r t stop t o l i m i t upward (I7 I U S travel t o i/4 in.

Springl

LLTU I U S

I ward t r a v e l t o 3/8 i n . -

178 The piping between t h e heat exchanger and t h e reactor, l i n e 102, a l s o has a variable spring support, S-2.

As t h e system i s heated t h e

net thermal expansion of l i n e 102 i s downward about 3/8 i n .

L3 -

The support

i s i n s t a l l e d with a spring s e t t i n g of 234 l b s , which i s 82 l b s l e s s than

t h e calculated hot position loading of 316 l b s .

During system heatup, t h e

3/8-in. downward expansion of t h e pipe e x e r t s a force of 17 l b s and compresses t h e spring t o t h e stop.

The u n i t then a c t s as a r i g i d support and

when f u e l salt i s added t o t h e system t h e r e i s no f u r t h e r spring d e f l e c t i o n . Supports S-1 on l i n e 100, S-5 on l i n e 201, and S-9 on l i n e 200, each c a r r y t h e weight of a freeze flange.

Since t h e movement of t h e pipe

a t these p a r t i c u l a r support points i s negligible, rigid-type supports a r e used. The piping supports i n t h e coolant c e l l a r e described i n Section 8.6.2 and those i n t h e f u e l drain tank c e l l i n Section 6.5.

5.6.4

Freeze Flanges Mechanical -type j o i n t s a r e provided i n the 5-in. piping i n t h e

f u e l and coolant-salt systems i n s i d e t h e r e a c t o r c e l l t o permit t h e major equipment t o be disconnected and removed f o r maintenance o r replacement.

The locations of t h e f i v e flanged j o i n t s a r e shown i n

t h e flowsheet, Figure 5.3. The so-called"freeze flange" type of j o i n t was adopted because of i t s proven r e l i a b i l i t y i n providing t i g h t connections with zero s a l t leakage and i n s i g n i f i c a n t gas leakage under a l l a n t i c i p a t e d thermal cycling conditions.

It i s a l s o a j o i n t i n which t h e s a l t does

not contact t h e r i n g - j o i n t gasket, an important f a c t o r i n t h a t residual salt would be d i f f i c u l t t o remove with remotely-operated tooling.

Salt

p a r t i c l e s i n t h e r i n g j o i n t could cause corrosion of t h e s e a t i n g surfaces when t h e salt i s exposed t o moisture and a i r and thus make t h e j o i n t d i f f i c u l t t o r e s e a l t o t h e necessary l e a k t i g h t n e s s .

There i s a l s o an

advantage t o keeping t h e salt out of t h e r i n g j o i n t i n t h a t t h e r e i s l e s s s c a t t e r of salt p a r t i c l e s as t h e flanges are separated. Figure 5.29 shows a s e c t i o n a l view of a t y p i c a l flange and clamp assembly ( a l s o see ORNL Dwg. E-GG-C-40610). The 23-in.-diam flanges a r e held together by two semi-circular spring s t e e l clamps which a r e forced around t h e circumference of t h e flanges.

The spring a c t i o n

179

. f

UNCLASSIFIED ORNL-LR-DWG 63248132

FLANGE CLAMP-

t -~

5in.

BUFFER CONNECTION

(SHOWN ROTATED) MODIFIED R-68 RINGGASKET

FROZEN SALT SEAL-

in. R

-in.+ (TYP) SLOPE 1:4

180 exceeds t h e piping code

106

requirements f o r gasket loading i n pro-

viding more than 136,000 l b of clamping force and a l s o affords a more constant gasket loading during thermal cycling than would be obtainable with more r i g i d fastenings, such as bolting.

The arrangement a l s o

was amenable t o design of equipment and t o o l i n g f o r remote assembly and disassembly of t h e j o i n t from above. Hydraulically operated jacking t o o l s a r e lowered i n t o t h e c e l l t o provide t h e f i v e t o t e n tons of force required t o i n s t a l l t h e clamps. Once i n s t a l l e d , no e x t e r n a l force i s required t o keep t h e clamps i n place.

The same jacking t o o l s a r e used f o r separating t h e clamps

and t h e forces required a r e only s l i g h t l y l e s s than those needed f o r installation.

A clamping frame i s provided f o r each of t h e f i v e

flange i n s t a l l a t i o n s i n s i d e t h e c e l l but t h e jacking t o o l s , e t c . , a r e interchangeable and may be used a t each location.*

5.6.4.1

Flanges.

The flanges a r e f a b r i c a t e d of INOR-8and

a r e about 23-1/8 i n . OD and 1.484 i n . t h i c k when measured through t h e t h i c k e s t portion of a flange face.

They a r e t h e welding-neck type.

The male flange has a guide ring, 5.798-5.802 i n . d i m by 1.248-1.252 i n . long, welded i n t o t h e face on t h e same c e n t e r l i n e . The outside of t h e guide r i n g i s tapered a t 15" so t h a t as t h e flange faces a r e brought together during assembly operations t h e r i n g w i l l e n t e r a s i m i l a r l y shaped opening i n t h e female flange t o guide t h e two together i n correct alignment (see ORNL Dwg D-GG-C-40611 and 40612).

I n each case t h e male flange i s i n s t a l l e d f a c i n g "uphill"

i n t h e salt piping, a l l of which slopes a t 3" t o promote drainage. A groove, 0.344 i n . wide x 0.25 i n . deep x 20.375 i n . p i t c h

diam, i s machined t o close tolerances i n t h e face of both t h e male and female flanges t o accommodate t h e r i n g gasket.

The flange faces

a r e a l s o machined i n t h e v i c i n i t y of t h e grooves t o serve as gaging surfaces.

E i t h e r t h e male o r t h e female flange i s d r i l l e d with a

3/32-in.-diam

hole through t h e bottom of t h e groove f o r t h e helium

buffer gas and leak-detection connection.

The flange half selected

*Due t o crowded conditions, t h e flange i n l i n e 100 may require a s p e c i a l o f f s e t jacking t o o l .

i s t h e one judged t o be l e s s l i k e l y t o require removal.

The hole i s

trepanned on t h e back s i d e of t h e flange f o r t h e welding of a l/8-in. sched-40 pipe.

The connection i s made a t a point on t h e flange which

f a l l s between t h e two semi-circular spring clamps (see ORNL D-GG-C-40615). The s l i d i n g surfaces for t h e clamps on t h e backs of t h e flanges

have f i r s t a 6" and then a 3" slope t o draw t h e flanges t i g h t l y together, and then a ramp with 0" slope t o make t h e clamps s e l f - r e t a i n i n g . These surfaces have a machined f i n i s h (32 RMS micro-in.) and a r e caref u l l y contoured t o provide t h e required gasket loading with a minimum of surface g a l l i n g o r s t r e s s concentrations.

A graphite-alcohol l u b r i -

cant, "Nearlube," i s applied t o t h e flanges before applying t h e clamps. A s indicated i n Fig. 5.32, a clearance of 0.030 i n . i s provided

between the flange faces a t t h e outer circumference t o take care of tolerances i n machining of t h e r i n g gasket and groove and a l s o t o allow f o r deformation of t h e flange under i n t e r n a l pressure loading,

a condition which tends t o close t h e clearance gap a t t h e outer edge. A groove, o r l i n e , i s cut around t h e circumference of each flange

d i s c t o serve as a reference mark f o r t h e o p t i c a l alignment of piping inside the reactor c e l l . The outside edge of both t h e male and female flanges has two projecting lugs, o r e a r s , horizontally 180" apart, which a r e used i n t h e disassembly operation t o be described subsequently.

A s shown i n

ORNL D w g s D-GG-C-40611 and 40612, these e a r s a r e about 1.625 i n . wide

and project about 1-1/4 i n . Flange loadings, s t r e s s e s , and deformations are discussed s e p a r a t e l y under Sections 5.6.4.6 5.6.4.2

Ring Gasket.

nickel (ASTM B-160).

and 5.6.4.7,

following.

The r i n g gasket .is fabricated of

T h i s material w a s s e l e c t e d because it i s

s u f f i c i e n t l y s o f t e r than INOR-8 t o s e a t properly and has a similar c o e f f i c i e n t of thermal expansion* t o remain t i g h t m e r thermal cycling.

The r i n g has a p i t c h diameter of 20.375 i n . (+ 0.002 i n . )

and has t h e imier and outer edges rounded t o a radius of 0.155-0.157 c o e f f i c i e n t of thermal expansion f o r N i a t 1009 i s 5.66 f o r INOR-8t h e value i s 6.45 x 10-6 i n . / i n . - v i n t h e 70-4009 range. -he

t4 5

x loe6 in./in.-"F';

182 i n . The r i n g i s machined t o t h e close s e a t i n g tolerances required through use of a s p e c i a l j i g furnished t o t h e manufacturer, as shown

bG A

on ORNL Dwg D-GG-C-40614. I n common with other leak-detected r i n g joings i n t h e MSRE, t h e gasket s e a t s on both s i d e s of t h e groove t o form two sealed spaces which a r e buffered with helium and monitored f o r leakage.

A 1/16-in.-

d i m hole i s d r i l l e d through t h e r i n g i n two places t o allow t h e sealed and buffered spaces t o communicate. The i n s i d e surface of t h e r i n g i s d r i l l e d with e i g h t equallyspaced 1/16-in.-diam

holes, about 5/32 i n . deep, t o accept t h e re-

t a i n i n g pins on t h e salt screen, t o be described subsequently.

The

inside surface of t h e r i n g a l s o has a "notch" 0.062 i n . deep and t o a radius of 1 i n . a t t h e bottom and two side-by-side i d e n t i c a l notches

a t t h e t o p t o engage t h e remotely operated t o o l used t o maneuver t h e r i n g during maintenance (see ORNL Dwgs D-GG-C-40611 and 40614). A small 304 s t a i n l e s s s t e e l bracket i s fastened with flush-headed

screws t o t h e outside of t h e seal r i n g a t t h e top.

This bracket

supports a 1-in.-long horizontal p i n formed from a 304 s t a i n l e s s s t e e l

1/4 i n . x 20 UNC b o l t which has t h e t o p portion of t h e threads ground T h i s pin i s i n s e r t e d i n a 1/4-in. tapped hole a t t h e t o p of

away.

t h e male flange when t h e r i n g i s t o be positioned f o r reassembly of t h e joint.

The l a c k of threads on t o p of t h e p i n allows it t o be slipped

i n t o t h e hole, but when released, t h e threaded portion prevents it from s l i p p i n g out, thus r e t a i n i n g t h e r i n g i n position f o r mating of t h e two flange faces.

All t h e male flanges a r e made with a similar

tapped hole on t h e bottom t o allow them t o be i n s t a l l e d e i t h e r s i d e up and thus provide more interchangeability of p a r t s (see ORNL D-GGC-40617).

5.6.4.3

S a l t Screen.

The 0.050-in. -wide clearance between t h e

male and female flange faces contains a s a l t - r e t a i n i n g screen formed wire on a 20-by-20 t o t h e inch mesh. of 0.015-in. OD INOR-8

Salt

entering t h e c a v i t y s o l i d i f i e s on t h e screen, t h e uninsulated flanges being cooled by l o s s of heat t o t h e c e l l atmosphere. of cooling i s required.

No other source

183

A t a salt temperature of 1 2 O O V , t h e freeze point i s about 5-5/8 in.

r a d i a l l y from t h e center of the pipe.

This distance decreases about

11/16 i n . f o r every 100°F decrease i n bore temperature. lo8 The screen helps somewhat i n preventing t h e salt from moving r a d i a l l y outwards, but, more importantly, when t h e j o i n t i s disassembled, provides a convenient Eeans of removing t h e frozen salt as an i n t a c t cake. s c a t t e r i n g of salt p a r t i c l e s i s thus avoided.

Undue

The flange faces have

very l i t t l e salt adhering t o them. The outer edge of t h e screen has e i g h t equally spaced r a d i a l c

pins, 1/16 i n . d i m by 3/4 i n . long, which engage t h e aforementioned holes i n t h e s e a l r i n g t o j o i n t h e two u n i t s together f o r convenience i n handling.

The outside edge of t h e screen has a 3-in.-wide by

3/4-in. notch a t t h e t o p and a l-l/k-in.-wide

by 3/4-in.

notch a t the

bottom t o allow access f o r t h e r i n g gasket holding t o o l mentioned above.

(See ORNL Dwg D-GG-C-40617)

5.6.4.4

Clamps.

The clamping rings a r e fabricated of N o . 4130

heat-treated s t e e l forgings made t o ORNL Specification 81-180, and as shown on ORNL Dwg D-GG-C-40616.

a r e quenched from 1550'F hardness of 380 BHN.

After welding, t h e clamp assemblies

and tempered a t 800V t o obtain a surface

This material was proven t o have a s u f f i c i e n t l y

high y i e l d strength t o provide t h e necessary clamping load, and w i t h t h e hardened surfaces, t o be s u f f i c i e n t l y compatible w i t h t h e INOR-8 8

t o minimize galling.

The clamping rings a r e more o r less U - s h a p e d i n cross section, w i t h t h e base portion about 1 i n . t h i c k and t h e l e g s tapering t o 5/8

i n . i n thickness at t h e ends.

2.908 i n . (+O ,010 i n . ) .

The clearance between t h e l e g s i s

The semi-circular pieces have t h e i n s i d e

corners rounded t o a 3/4-in.

radius and a r e contoured t o prevent digging

i n and g a l l i n g of t h e INOR-8 flanges a t these points (see ORNL Dng D-GG-C-406'16)

Right and l e f t hand guide e a r s a r e welded t o both t h e upper and lower clamp halves.

These e a r s a r e a l s o f a b r i c a t e d of No. 4130 s t e e l

and are heat t r e a t e d along with the clamps.

Each ear is formed of

two more o r l e s s i d e n t i c a l pieces w i t h a 1/8-in. gap i n between. This arrangement w a s proven necessary t o prevent s t i f f e n i n g of t h e t

backbone of t h e clamp a t t h e e a r location, with subsequent overstressing o r g a l l i n g of t h e s l i d i n g surfaces a t these points.

1-5/8-in. by 2-l/32-in.

The e a r s have a

Lj. e

opening through which t h e clamping-f rame guide

bars pass, as w i l l be explained i n Section 5.6.4.5,

t o follow.

The t o p and bottom halves of t h e clamp a r e each d r i l l e d w i t h a 1-5/8-in. - d i m hole t o permit passage of t h e 1-1/2-in. -diam load transmitting rod on t h e clamping frame, as described below.

5.6.4.5

Clamping Frame.

The clamping frame assembly i s shown

schematically i n Fig. 5.30 and on ORNL Dwg E-GG-C-40610.

The frame

allows t h e clamps t o be moved as a u n i t i n t o position around t h e mating flanges and then serves as a leverage point f o r applying hydraulic jacks on each side of the clamps t o draw them together. Since t h e frame e n c i r c l e s t h e pipe, it must remain i n s i d e t h e reactor c e l l a f t e r assembly of a j o i n t .

For storage it i s moved along t h e

pipe t o a supporting rack. The clamping frame i s about 33-5/8 i n . wide by 55-1/2 i n . high

and i s 7 i n . t h i c k . Grade C s t e e l .

It i s fabricated, i n most part, of ASTM ~ 2 8 5

The upper and lower pieces of t h e assembly a r e joined

by 1-1/2 x 2 x 34-in.-long guide bars on each s i d e . lower ends of these two bars have 1-3/8-in.-long

The upper and

oblong holes through

which a 3/4-in.-diam pin i s mounted t o provide a freedom of movement of t h e upper and lower elements t o make t h e clamps s e l f - a l i g n i n g . The i n s i d e of t h e rods a t mid-height have two projecting lugs t o engage t h e lugs on t h e outer rims of t h e flanges, as mentioned above. A 1-1/2-in.-diam

rod extends downward about 10 i n . from t h e

center of t h e upper element, o r beam, of t h e frame and a s i m i l a r rod extends upward from t h e lower beam, both rods passing through t h e holes i n t h e respective semi-circular clamps.

The purpose of these

rods i s t o transmit t h e load, o r force, when removing t h e clamps. Brass pads a r e brazed on t h e ends of t h e rods t o avoid i n j u r y t o

t h e flanges.

The distance between t h e ends of t h e rods i s about 1/4

i n . greater than the o v e r a l l diameter of t h e flange discs. To i n s t a l l t h e frame it i s f i r s t moved from t h e storage rack using t h e l i f t i n g - s

on the upper clamp.

I n t h i s position, t h e

upper beam w i l l drop down u n t i l i t s e a r s bear against t h e clamp ears.

. c

Unclassified ORNL DWG 64-8821

Representation of Clamp Operator Tool Clamp Beam ,

GIlid@ Bars Nezz c&Imp--'

I 1

m P

t a

PiIl Joint/

i .

Putting Bat+ Clsqs

lkimoving Upper Clamp

Figure 5#30e Freeze Flange Clsmping Frame Showing Assenibly and Disassembly.

186 The lower clamp a l s o drops down with i t s e a r s bearing against t h e lower guide-rod-pin j o i n t housing. The frame i s then moved horizontally

along t h e pipe and l i f t e d i n t o position with t h e lugs on t h e flange r i m s between the two lugs on t h e frame guide bars.

The clearance

between t h e lugs i s about 3/32 i n . so that close alignment i s not required. The upper clamp i s then lowered, as indicated i n Fig. 5.30, so that t h e bottom end of t h e upper load-transmitting rod r e s t s on t h e

t o p of t h e flange, t h e clearance i n t h e pinned j o i n t s on t h e guide bars allowing t h e necessary movement.

The hydraulically operated

jacking t o o l s a r e then applied t o each side, t h e j a w s of t h i s t o o l closing around t h e t o p of t h e upper clamp e a r and t h e bottom of t h e lower clamp ear.

The jacks a r e operated simultaneously, drawing

the clamps i n t o position.

The pressure t o t h e jacks can be varied

as required t o draw t h e clamps on evenly.

The force required on

each s i d e i s 12,000 t o 24,000 l b , depending on t h e condition of t h e s l i d i n g surfaces, t h e sum of t h e dimensional tolerances, e t c . I n disassembly of a j o i n t , t h e lower clamp i s removed f i r s t . The j a w s of t h e jacking t o o l are placed above t h e e a r s on t h e lower clamp and below t h e lower pin j o i n t housing, as shown i n Fig. 5.30. The lower load-transmitting rod w i l l push against t h e bottom of t h e flanges and transmit t h e jacking force, with no load being c a r r i e d by t h e pin j o i n t s on t h e guide bars.

Unequal d i s t r i b u t i o n of t h e

f r i c t i o n between t h e clamp and t h e flanges may cause one s i d e of t h e clamp t o tend t o "get ahead" of t h e other, an a c t i o n which i s s e l f multiplying.

The r e s u l t i n g forces tending t o move t h e frame out of

vertical, i.e.,

r o t a t e about t h e flange, a r e counteracted by t h e lugs

on t h e flange r i m s bearing against t h e lugs on t h e guide bars.

Since

t h e f i r s t r o t a t i o n a l movement takes t h e "slack" out of t h e pinned guide bar j o i n t s , t h e position of t h e pin i n t h e s l o t t e d holes serves as an indication t o t h e operator that t h e jacking force on one s i d e

of t h e clamp should be reduced.

I f s u f f i c i e n t imbalance occurs t o

move t h e guide bars t o t h e l i m i t of t h e i r t r a v e l i n t h e pinned j o i n t , t h e end of t h e bar b u t t s against t h e housing t o transmit t h e load r a t h e r than a c t i n g through t h e pin.

187

The upper clamp i s then removed, using t h e jacking t o o l as

. I

shown i n Fig. 5.30.

The upper load-transmitting rod i s e f f e c t i v e

i n t h i s case and, again, t h e guide rods and pins c a r r y l i t t l e of t h e load.

The force required t o remove a clamp i s only s l i g h t l y

l e s s than that needed t o i n s t a l l it. A f t e r both clamps have been loosened, t h e upper clamp and frame assembly can be r a i s e d and moved horizontally out of t h e way. Once t h e flanges have been separated by more than 2 t o 3 i n . , t h e frame could be removed from t h e reactor c e l l , should t h i s be

desirable. J.

A d e t a i l e d description of operation of t h e clamping frame and P

associated t o o l i n g i s given i n Maintenance Procedures, P a r t X. 5.6.4.6

G a s Leak Rates During Thermal Cycling.

Changes i n

gasket loading, and thus t h e gas l e a k r a t e , occur during temperature cycling.

This i s due t o t h e differences i n t h e c o e f f i c i e n t s of

thermal expansion of t h e flange material (INOR-8),t h e r i n g gasket (nickel), and t h e flange clamps (No. 4130 carbon s t e e l ) .

The

r e s i l i e n c y of t h e clamps, however, causes t h e load on t h e gasket t o be more constant than i f more r i g i d fastenings were used. Even i f excess temperatures existed a t a freeze flange, allowi n g t h e salt t o come i n contact with t h e r i n g j o i n t gasket, no salt

(Some damage might be done t o the r i n g seal, however.) Thus, t h e only manner i n which salt could l e a k would be f o r gross f a i l u r e and separation of t h e flange faces. Tests of leakage would occur.

e a r l y models of t h e freeze flanges demonstrated, however, that gas leakage could be encountered. logFor t h i s reason, t h e development

t e s t s were primarily concerned with measurements of helium gas leak~

age from t h e leak-detected buffer zones.

Tests of t h e e f f e c t of thermal, cycling on gas t i g h t n e s s showed that t h e MSRE flange design maintained acceptable gas s e a l s under

high temperature (about l3OO’T),

under r e p e t i t i v e cycling ( i n which

t h e temperature was r a i s e d from l5OV t o l3OOV and returned t o 150°F i n a 24-hr cycle, f o r more than 100 cycles), and under severe temperat u r e t r a n s i e n t s (lOO°F/min f o r s i x minutes).

L, 4

(See p 10 ref 110)

The j o i n t s displayed t h e desirable c h a r a c t e r i s t i c of having a smaller

188 gas leak r a t e a t t h e higher temperatures than a t lower.

After 36

thermal cycles, t y p i c a l l e a k rates were 2.6 x

-6

condition and 0.39 x 10

cc/sec i n t h e 1300'F

cc/sec i n t h e cold condition (see p 45

ref 108). The e f f e c t on t h e leak r a t e of t h e interchangeability of parts

was investigated (see p 41 ref 108).

Two female flanges were thermal

cycled several times and then mated w i t h new (uncycled) male flanges and gasket rings t o simulate t h e s i t u a t i o n which might e x i s t i n t h e replacement of a major component i n t h e reactor c e l l .

Both pairs

sealed s a t i s f a c t o r i l y , even a f t e r subsequent extensive thermal cycling. A gasket r i n g with an octagonal cross section w a s found t o s e a l

b e t t e r than one with an oval cross section, but both performed more than adequately (see p 43 ref 108).

5.6.4.7

Loading and S t r e s s e s .

The clamping force which can

be exerted by t h e clamps w a s estimated t o be between 136,500 l b and 241,200 l b , depending upon t h e combinations of tolerances that could e x i s t i n t h e f i t of t h e various parts. 111 The gasket loading required f o r proper s e a t i n g w a s calculated using t h e method outlined i n Par UA-47 of Section VI11 of t h e ASME Unfired Pressure Vessel Code47, and estimated t o be about 28,800 l b .

The clamps a r e

thus capable of s e a t i n g t h e r i n g gaskets w i t h ample reserve f o r withstanding pipe s t r e s s e s and i n t e r n a l pressure. The force required t o drive t h e clamps onto t h e flanges i s a

maximum j u s t as t h e l e g s of t h e clamp s l i d e onto t h e ramp w i t h 0' slope. This force was estimated t o be 24,750 l b f o r each side of t h e clamp ( i f t h e clamping force i s 241,200 l b ) , o r a t o t a l of 49,500

l b f o r each of t h e clamp halves.

This estimate assumes a c o e f f i c i -

ent of f r i c t i o n between t h e clamp and t h e flange of 0.15, a value which i s ample i n most cases but could be exceeded i f g a l l i n g should occur. Under maximum clamping e f f o r t , t h e maximum s t r e s s i n t h e clamp

was estimated t o be about 90,500 p s i , and t h e maximum clamp d e f l e c t i o n The clamp i s forged and heat t r e a t e d t o have a y i e l d 111 strength of g r e a t e r than 100,000 p s i .

0.092 i n .

189 The mechanical s t r e s s e s i n t h e flange due t o axial loadings r e s u l t i n g from thermal expansion i n t h e piping systems were found t o be less than 4000 p s i .

pressure.

This value includes t h e e f f e c t of i n t e r n a l

The t o t a l a x i a l loading r e s u l t i n g from a s t r e s s of 4000 psi

i s 17,200 l b (based on 6-in. OD by 0.204-in. w a l l thickness tubing).

The allowable axial loading on t h e flange was estimated''' methods developed i n t h e Sturm-Krouse study,'l3

using

and based on an

allowable working stress range of 30,000 psi,* a value of 86,936 l b obtained.

The flange i s thus capable of withstanding t h e axial

loadings with a f a c t o r of s a f e t y o r more than four. The flange i n t e r n a l thermal s t r e s s e s were analyzed both a n a l y t i c a l l y and by photoelastic s t u d i e s t o determine t h e s t r e s s concentration factors.

(These estimates were based on 6-in. OD tubing, but

a r e applicable. )

These s t u d i e s indicated that t h e stresses could

be higher than t h e e l a s t i c l i m i t and that p l a s t i c s t r a i n could e x i s t . Development t e s t s proved t h a t both radial and transverse s t r a i n s occur, t h e former causing a reduction i n t h e bore diameter, and t h e l a t t e r a d i s t o r t i o n of t h e plane surface of t h e face.

One t e s t showed

t h a t after 36 thermal cycles t h e female flange bore decreased by 10

mils and t h e male bore by 30 mils.

No permanent d i s t o r t i o n was

noted on t h e o u t e r surfaces of t h e flanges ( a f t e r 30 cycles) but t h e "out-of-flatness" of t h e i n t e r i o r face of t h e female flange increased f r o m 14 mils t o a value of 18 mils.

male face.

No warpage w a s detected i n t h e

These s t r a i n s a r e judged t o be of such magnitude that a

l a r g e number of s t r a i n cycles could be applied without f a i l u r e . 113 Further, t h e differences between t h e deformations of t h e faces at

13009 and a t 8509 ( t h e salt liquidus temperature) a r e not s u f f i c i e n t l y great that "excess" salt could be trapped between t h e flange faces t o cause abnormally high s t r e s s e s o r d i s t o r t i o n s .

Thus, t h e p l a s t i c s t r a i n

that occurs i s small and flanges of t h e design used i n t h e MSRE have undergone more than 100 thermal cycles (probably equivalent t o 10 t o 1 5 years of normal MSRE operation) with no s i g n i f i c a n t leakage, o r defor111 m t i o n s of consequence.

*As indicated i n t h e footnote, Section 5.6.2, f o r t h e stress range i s 32,125 p s i .

a more recent value

190

5.6.5

F'reeze:yalves

5.6.5.1

General Cescription.

The flow of salt i n t h e MSRE

drain, fill and processing systems i s controlled by freezing o r thawi n g a short plug of salt i n a f l a t t e n e d section of 1-1/2-in. pipe, c a l l e d a "freeze valve."

T h i s arrangement w a s adopted f o r t h e MSRE

because of a l a c k of a mechanical-type valve w i t h a proven r e l i a b i l i t y i n molten-salt service.*

The freeze valve concept, on t h e other hand,

has a good record of s a t i s f a c t o r y application.

While mechanical-type

valves would have t h e advantage of f a s t e r a c t i o n and a b i l i t y t o modul a t e t h e flow, t h e freezing and thawing times f o r t h e freeze valves

are s a t i s f a c t o r i l y short and t h e "on-off" type of flow control does not impose any p a r t i c u l a r handicap. There a r e a twelve freeze valves i n t h e MSRE. I

A l l are fabri-

S i x a r e i n s t a l l e d i n 1-1/2-in. l i n e s and s i x

cated of 1-1/2-in.

pipe.

i n 1/2-in. l i n e s .

As may be noted i n Table 5.11,

one f r e e z e valve i s

located i n t h e reactor drain and fill pipe, l i n e 103, and i s i n s i d e t h e reactor furnace.

S i x of t h e freeze valves a r e i n t h e f u e l drain

tank c e l l , t h r e e a r e i n t h e f u e l processing c e l l , and two are i n t h e

coolant c e l l . Figure 5.32 shows t h e general arrangement a t a f r e e z e valve. The valve i l l u s t r a t e d i s used a t FV-104, lo5 and 106, but with t h e

exception of the f l a t - p l a t e heaters, i s a l s o t y p i c a l of valves lo7 through 112.

E l e c t r i c heat i s applied, e i t h e r d i r e c t l y or i n d i r e c t l y ,

t o t h a w a valve and t o keep it i n t h e open condition.

A stream of

cooling g a s H o r a i r i s used t o cool t h e pipe s e c t i o n t o freeze a &

s a l t plug and p o s i t i v e l y s t o p t h e salt flow.

Some system gases may

d i f f u s e through t h e frozen plug but t h e seepage through t h e valve i s inconsequential t o operation of t h e MSRE. *Preliminary investigations a t ORNL of Kenametal s e a t s and poppets, e l e c t r i c a l l y - d r i v e n actuators, e t c . , indicated that a mechanicaltype valve f o r molten-salt service may be p r a c t i c a l provided that a s a t i s f a c t o r y stem s e a l could be devised w i t h reasonable e f f o r t .

*%ell atmosphere gas, consisting of about 95% Ng and 5% 02.

L, ri

191

Table 5.11 treeze 1 lalve ;ine No.

103

Cell in which

Line Function

is Located

Line Size in. IPS

MSRE

Freeze

Valves

I I

rype of Heater and Insulatiod

Reactor drain and f i l l

Reactor

1-112

Calrod around hor. f l a t sectiod; gas f l o w shroud with insulatiod.

Coolant supply Gas Line No.

919

N2a

Gas F11 W,

SCfm

High Rate

Holding . Rate

Insulated gas f l o w box with removable f l a t - p l a t e ceramic heaters on adjacent piping.

Flush tanlr drain and fill

Fuel Drain Tank

1-1/2

Fuel Drain Tank

1-1/2

105

Drain Tank No. 2 drain and fill

Drain Tank No. 1 drain and' fill

Fuel Drain Tank

lo7

Transfer t o f u e l processing

Fuel Drain Tank

108

Transfer t o f u e l processing

Fuel Drain mnk

112

109

Transfer t o f u e l processing

Fuel Drain Tank

112

Transfer t o f u e l storage

Fuel Processing

112

Transfer t o portable cans

Fuel Processiw

112

Transfer t o salt disposal

Fuel Processing

112

204

Coolant system drain

ll0

206

Coolant system drain

Drain CoolarIt Drain

i I N 2 l 911 I -

High rate, or freezing gas flow.

Low rate, or holding gas flow.

fir

929

Air

906

1-112

fir

907

e Thermocouples l i s t e d a r e only those with "FV" prefix.

- 546 02)

969

freezer section. Adjacent pipe has permanently-installed curved p l a t e ceramic heaters and insul.

a Cell atmosphere gas (9546 N2

Air

no shroud and no insulation on

Deep frozen, no gas flow req'd

1 f Abmr 20 i n . from center I of valve on l e g without pot. 1g ~

'e I

< 10

< 20

> 30

Down t o

754, 11

1-112

- N o t applicable, or not important.

Calrod around hor. f l a t section;

15c

Insulated gas flow box with pem manentlv-installed curved p l a t e piping. M e r i o r insulation ~, covers piping heaters and freezer section. spare heaters are id' stalled.

Temperatur E H t r . On Freezing Gas On Dam t o

> Greater than. Less.than.

35-70 11

112

with

Time

7ob

908

w Without

Parer

104

Thawing Time, min

Freeze Time,

Gas

A t t e e between freeze valves 105 and 106.

192

The valve "body" i n each case consists simply of a f l a t t e n e d section of the piping about 2 i n . long.

The shaping w a s done a t

room temperature using a forming die i n a hydraulic press. es,

Each

section was dye-checked after forming, although there was no evidence

Thermocouple Numberse

3 4 3B

3$ 3B I

2A, 2B

none

A4, B4

2 ;: A4, u,LB 3% 3B

A4, B4

none

6$ 6Bf

Freeze

none

103

evidence of over-stressing o r cracking.

A l l the freeze sections,

w i t h the exception of t h e one i n l i n e 103, a r e i n s t a l l e d with the 104

6% 6Bg 5 4 5B

105

5A, 5B

Sections i d e n t i c a l t o those used i n

t h e MSRE were t e s t e d through more than 200 freeze-thaw cycles without

5A, 5B

none

of a tendency f o r cracking.

f l a t faces i n a horizontal plane. A cooling gas flow of 1 5 t o 35 scfm w i l l freeze a valve, i n i t i a l l y at 1200V, i n 1 5 t o 30 minutes.

106

The g a s flow i s then

reduced t o 3 t o 7 scfm t o maintain t h e valve i n the frozen condition

2A, 2B

(i.z., with the salt below 850°F) but limiting t h e growth -

of t h e frozen plug t o the freeze valve section.

To allow longer

plugs could cause unacceptably long thawing times and/or present t h e opportunify t o t h a w the center section of t h e plug while t h e

2A, 2B

ends remain s o l i d , thus perhaps overstressing the pipe w a l l . I n most cases a shroud, o r box, i s used t o d i r e c t t h e flow of cooling gas around t h e freeze valve section and t o prevent t h e

gas from cooling nearby heated surfaces.

2A, 2B

2% 2B

The thermal insulation

arrangement at the freeze valve helps e s t a b l i s h the freezing and

2A, 2B

3 4 3B

thawing times. Ab, B4

none

5A, 5B

204

plication.

The time allowed depends upon t h e p a r t i c u l a r ap-

For example, the freeze valve i n l i n e lo3 i s designed

t o melt t h e plug i n about 5 minutes, while others may take sub-

.I I &

s t a n t i a l l y longer. Short v e r t i c a l lengths of &-in. NPS piping a r e placed a t most

freeze valves t o form syphon breaks, o r "pots," which insure that ample salt w i l l remain i n the freeze valve section after a salt transf e r t o provide a f u l l and s o l i d frozen plug.

Where freeze valves a r e

i n s t a l l e d i n 1/2-in. l i n e s , t h e pipe s i z e changes t o 1-1/2 i n . a t t h e reservoir. Design and development of the freeze valves did not lend its e l f t o a n a l y t i c a l treatment of the stresses, heat t r a n s f e r , etc., because of the irregular shape of t h e section and t h e unpredictable temperature d i s t r i b u t i o n s .

The MSRE freeze valves, therefore, are

i 192 The valve "body" i n each case consists simply of a flattened

3 I .

section of t h e piping about 2 i n . long.

The shaping w a s done a t

room temperature using a forming d i e i n a hydraulic press.

Each

section was dye-checked a f t e r forming, although there was no evidence of a tendency f o r cracking.

Thennocouple Numberse

Sections i d e n t i c a l t o those used i n

jhoulders From Ends At in*

t h e MSRE were t e s t e d through more than 200 freeze-thaw cycles without evidence of over-stressing o r cracking.

A l l the freeze sections,

none

Freeze

none

lo3

with t h e exception of t h e one i n l i n e 103, a r e i n s t a l l e d with the

f l a t faces i n a horizontal plane. A cooling gas flow of 1 5 t o 35 scfm w i l l freeze a valve,

i n i t i a l l y a t 1200OF, i n 15 t o 30 minutes.

6A, 6B@; 5% 5B

105

5 4 5B 6 4 6B

109

I 212; I

ll0

none

5A, 5B

111

none

5 4 5B

112

none

5A, 5B

204

none

206

The gas flow i s then

reduced t o 3 t o 7 scfm t o maintain the valve i n t h e frozen cond i t i o n (i.E., -

with the salt below 850OF) but limiting the growth

of t h e frozen plug t o the freeze valve section,

To a l l o w longer

plugs could cause unacceptably long thawing times and/or present t h e opportunity t o t h a w the center section of t h e plug while t h e

none

ends remain solid, thus perhaps overstressing t h e pipe w a l l . I n most cases a shroud, o r box, i s used t o d i r e c t t h e flow of cooling g a s around the freeze valve section and t o prevent t h e gas from cooling nearby heated surfaces.

plication.

The thermal insulation

arrangement a t t h e freeze valve helps e s t a b l i s h t h e freezing and thawing times.

The t i m e allowed depends upon t h e particular ap-

For example, t h e freeze valve i n l i n e lo3 i s designed

t o melt t h e plug i n about 5 minutes, while others may take subs t a n t i a l l y longer. Short v e r t i c a l lengths of b i n . NPS piping a r e placed a t most freeze valves t o form syphon breaks, o r ''pots,''

which insure that

ample salt w i l l remain i n the freeze valve section a f t e r a salt transf e r t o provide a f u l l and s o l i d frozen plug.

Where freeze valves a r e

i n s t a l l e d i n 1/2-in. l i n e s , t h e pipe s i z e changes t o 1-1/2 i n . a t t h e reservoir. Design and developnent of t h e freeze valves did not lend its e l f t o a n a l y t i c a l treatment of the stresses, heat t r a n s f e r , e t c . , because of t h e i r r e g u l a r shape of t h e section and the unpredictable temperature distributions.

The MSRE freeze valves, therefore, a r e

193 t h e r e s u l t of development t e s t i n g , primarily with regard t o t h e arrangement of t h e heaters and coolers t o a t t a i n t h e required freezing and thawing times, and t o provide s t a t i o n s that could be maintained with 114 remotely-operated tooling.

5.6.5.2

Definitions of "Deep Frozen, Frozen and Thawed". terms were defined t o have t h e following meanings: 115

Deep Frozen.

These

The salt plug i s frozen, and w i l l remain so,

even on l o s s of e l e c t r i c power, cooling gas supply, e t c .

The heaters

on t h e freeze valve are o f f , and may be off on piping adjacent t o t h e valve.

-b.

The cooling gas may o r may not be supplied t o t h e valve. Frozen.

Heaters on t h e valve a r e off but t h e heaters on

adjacent piping a r e on, t h e plug remaining frozen by t h e cooling a c t i o n of t h e gas stream.

These valves w i l l t h a w i n a specified

time if t h e e l e c t r i c power f a i l s (causing loss of t h e gas flow and power t o t h e heaters) and w i l l remain thawed f o r a t l e a s t 20 minutes.

-c. Thawed. E l e c t r i c heaters on adjacent piping and/or on t h e valve a r e on; t h e cooling gas flow i s o f f .

If e l e c t r i c power f a i l s ,

t h e valve remains thawed f o r a t l e a s t 30 minutes.

5.6.5.3

Thermocouples.

I n general, two thermocouples a r e

attached on t h e upper surface a t t h e center of each freeze valve section; two a r e attached t o t h e upper surface of each "shoulder" ( t h e t r a n s i t i o n between t h e round pipe and t h e f l a t t e n e d s e c t i o n ) , and one couple i s attached t o the bottom of t h e pipe a t each end about 5 i n . from t h e c e n t e r l i n e of t h e f r e e z e valve.

Thermocouple

locations a r e shown on ORNL Dwg D-RE-B-40543, and t h e thermocouple numbers a r e l i s t e d i n Table 5.11.

It i s t o be noted i n t h i s table

that o n l y t h o s e couples with a n "FV" p r e f i x a r e l i s t e d and that nearby thermocouples having l i n e number designations are not included. The chromel-alumel, mineral-insulated thermocau@es have Inconel sheaths 1/8-in. dim, and a r e attached by welding t h e sheath t o t h e ground surface of a weld-deposited INOR-8pad, about 3/8 i n . square by 1/16 i n . t h i c k , on t h e process piping.

A l l t h e i n s t a l l e d thermocouples are used i n t h e c i r c u i t r y . About half, those with an "A" suffix, lead t o control modules, and t h e others, w i t h a "B" s u f f i x , are used i n t h e monitoring c i r c u i t s . I f a spare

194 shbuld be needed, a monitoring couple can be diverted f o r t h a t purpose.

4 c

Some thermocouples provide t h e s i g n a l f o r two amplifiers, one f o r t h e low temperature setpoint and t h e other f o r t h e high setpoint.

If t h e temper-

a t u r e at t h e center section of a freeze valve rises above 130OoF, or f a l l s below a s e t value, an alarm w i l l be sounded. ' 1 6

The absolute value of t h e

control setpoint temperature depends upon t h e freeze valve function, t h e type of heaters and insulation, etc., so that study of each thermocouple i n s t a l l a t i o n i s needed i n t h e f i e l d t o m a k e f i n a l settings.

The nominal

setpoint temperatures a r e given i n t h e thermocouple tabulation, ORNL Dwg D-AA-B-40511.

5.6.5.4

Freeze Valve 103.

This freeze valve i s i n t h e reactor

drain and f i l l l i n e and i s located within t h e reactor furnace adjacent t o t h e reactor vessel.

It i s frozen, and maintained frozen, by a cooling

j e t of gas directed against it.

It thaws quickly when t h e gas flow i s

interrupted due t o t h e r e s i d u a l heat within t h e pipe w a l l . The 1 1/2-in.

sched 40 INOR-8drain l i n e i s f l a t t e n e d f o r a distance

of about 2 in. t o a flow area 1/2 i n . wide, giving it outside cross sectional dimensions of 0.79 x 2 1/2 in.,

overall.

The shoulders of t h e

f l a t t e n e d section make a n angle of about 30' w i t h t h e pipe axis.

The

valve i s i n s t a l l e d w i t h t h e f l a t t e n e d faces i n t h e h o r i z o n t a l plane,

as shown i n Fig. 5.31 and on ORNL Dwg E-GG-C-40603.

(If t h e f l a t t e n e d

faces had been mounted v e r t i c a l l y , special precautions would have been required t o eliminate t h e gas pocket tending t o e x i s t i n t h e projection of t h e f l a t t e n e d section above t h e top of t h e pipe, an e f f e c t found t o encourage porosity of t h e frozen plug.) The valve i s surrounded by a 2-3/4 x 2-in. long x 1-3/4-in. shroud fabricated of 1/16-in.-thick

INOR-8sheet.

high

One end of t h i s

shroud i s welded t o t h e process pipe and t h e other t o a 4-in.-diam bellows about 13/16 in. long, having two convolutions, and fabricated

of 20-gage INOR-8sheet. t h e process pipe.

The other end of t h e bellows i s welded t o

The bellows allows f o r d i f f e r e n t i a l expansion due

t o t h e shroud operating at a lower temperature than t h e pipe wall. i

UNCLASSIFIED ORNL-DWG. 64-6898

THERMOCOUPLES COOLING GAS

DRAIN TANKS

FIG. 5.31. FREEZE VALVE IN LINE 103

DRAIN LINE

The cooling gas enters t h e shroud from t h e side through a 3/4-in. OD tube, and leaves through a similar pipe on t h e opposite side.

The

shroud i s made concave on t h e top and bottom, a s shown on ORNL Dwg E-GG-C-40603,

t o increase t h e gas v e l o c i t y and improve t h e heat trans-

f e r i n those areas t o obtain more rapid freezing of t h e s a l t plug a t t h e center of t h e flow area. The freeze valve and shroud assembly a r e enclosed i n a 20-gage s t a i n l e s s s t e e l box about 8 in. wide x 5 in. high x 6 in. long, f i l l e d with Fiberfrax wool thermal insulation.

(See Section 5.6.6.3. )

Two sheathed thermocouples are i n s t a l l e d on t h e top outside f l a t tened face of t h e valve, t h e sheathes passing through sleeves i n t h e side p l a t e s of t h e shroud.

Two thermocouples a r e a l s o located on t h e

top shoulder of t h e valve opposite t h e bellows end, and two couples a r e located on top of t h e pipe immediately adjacent t o t h e bellows, a s shown on ORNL Dwgs D-HH-B-40543 and E-GG-C-40603. A Calrod heater, 0.315 in. d i m with Inconel sheath, of 1500-watt

capacity, i s formed i n t o a saddle shape and f i t s over t h e top of l i n e

lo3 between t h e freeze valve box and t h e e l e c t r i c a l connection t o t h e l i n e used f o r resistance heating between t h e reactor and the drain tanks.

The saddle-type heater i s removable with special tooling from

above through a special standpipe arrangement, as shown on ORNL Dwg D-GG-C-40604.

The heater may be needed t o prevent t h e pipe from be-

coming too cool i n t h e v i c i n i t y of t h e e l e c t r i c a l connection lug, and i s not d i r e c t l y associated with operation of t h e freeze valve.

The valve can be frozen by t h e 68 scfm j e t of cooling gas i n l e s s than 30 minutes. '15

When t h e temperature of t h e shoulders of t h e valve

reaches about 6 8 0 ° ~ , t h e cooling gas flow i s reduced t o about 1 5 scf'm; a t 65OoF a l l gas flow would be cut o f f .

When t h e temperature r i s e s

s l i g h t l y above 65OoF, t h e holding a i r would be resumed and i f t h e temperature reaches 85OoF t h e b l a s t a i r flow of 68 scfm i s again turned on.

5.6.5.5

Freeze Valves 104, lo5 and 106.

These freeze valves

a r e located i n t h e f u e l - s a l t drain tank c e l l i n t h e 1 1/2-in. transfer lines.

salt

One o r more a r e thawed when s a l t i s t o be transferred,

197

or when f l u s h or f u e l salt i s being c i r c u l a t e d i n t h e reactor system, but a r e deep frozen a t a l l other times.

The f l a t t e n e d sections on t h e process piping f o r these valves a r e e s s e n t i a l l y as described f o r FV-103, above, except that t h e f l a t s i d e s a r e mouqted i n t h e horizontal plane,

The general f e a t u r e s of

t h e cooling gas shroud, o r box, a r e indicated i n t h e sketch, Figure

5.34.

The cross s e c t i o n a l shapes of t h e shroud and t h e process pipe

a t t h e center of t h e freeze valve a r e very s i m i l a r . The shroud i s 2-1/8 i n . long, measured along t h e axis of t h e pipe, and has maximum o v e r a l l dimensions of 2-5/16 i n . high and 3-7/8 i n . wide.

The end

pieces a r e f a b r i c a t e d of 1/8-in. -thick INOR-8 p l a t e and a r e welded t o t h e process pipe.

The outside s h e l l , which i s welded around t h e

end pieces, c o n s i s t s of two l a y e r s of 0.024-in.-thick

INOR-8shim

stock separated by two thickness of 1 / 8 4 n . -thick Fiberfrax i n s u l a t i n g paper, Type 970-H.

Additional d e t a i l s are shown on ORNL

DWg D-GG-(2-55509. The cooling gas i s introduced a t t h e bottom of t h e shroud through 1/2-in. OD x 0.042-in.

w a l l thickness INOR-8tubing.

The gas c i r c u l a t e s

i n s i d e t h e shroud around t h e freeze valve section and leaves through

a similar 1/2-in. OD tube a t t h e bottom, t h e i n l e t and o u t l e t openings being separated by a 1/8-in.-thick b a f f l e . a 6-in.-long,

The i n l e t gas tubing has

316 stainless steel, corrugated f l e x i b l e connector

welded i n it t o provide f o r r e l a t i v e movement of t h e process pipe and theagas supply l i n e .

The gas discharge pipe terminates about

8 i n . below t h e freeze valve, the gas discharging i n t o the c e l l atmosphere. The thermocouple l e a d s a r e brought i n t o t h e shroud through t h e

exit gas tube.

Two chromel-alumel, mineral-insulated thermocouples

w i t h 1/8-in. OD Inconel sheaths a r e applied t o b u i l t - u p pads on t h e

t o p of t h e center section, as indicated i n Figure 5.32.

Two thermo-

couples a r e a l s o attached t o pads on t o p of each shoulder outside t h e cooling gas shroud. The cooling gas shroud i s enclosed i n t h e removable heateri n s u l e t i o n units f o r t h e process lines, see Section 5.6.6,

trl

The 3/4-in.-thick

following.

f l a t - p l a t e ceramic heaters (Cooley E l e c t r i c Mfg. Corp.,

.. 198 -

Indianapolis) are arranged on the s i d e s and t o p of t h e process piping, a r e attached t o t h e i n s u l a t i o n assembly and are removable with it. The

* \

heaters a t FV-104 consist of two sections, FV-104-1, made up of s i x heater elements w i t h a t o t a l capacity of 2.4 kw (at 230 v); and I

FV-104-3,

containing t h r e e elements with a t o t a l capacity of 2 kw

(at 115 v)

. The heaters a t FV-105 are arranged i n t h r e e sections:

FV-105-1 has s i x heater elements with t o t a l capacity of 2.4 kw ( a t 230 v ) , FV-105-3 has t h r e e heaters and a t o t a l capacity of 2.0 kw (at 115 v), and FV-105-4 has t h r e e heaters with t o t a l capacity of 1.95 kw (at 115 v)

FV-106-1 has s i x elements

Freeze valve 106 has two heater sections:

and a t o t a l capacity of 2.0 kw (at 230 v), and FV-106-3 has t h r e e elements and a t o t a l capacity of 2.0 kw ( a t 115 v)

A s shown on t h e Mirror Insulation Company Dwgs G - 1 1 8 ~and G-118C,

t h e heater p l a t e s a r e not applied f o r a distance of about 2 i n . along t h e pipe a t t h e cooling shroud, due t o t h e l a c k of space.

Sufficient

heat i s obtained by conduction along t h e process pipe t o thaw t h e

freeze valve.

Also, see ORNL Dwg E - M M - A - ~ ~ ~ ~ o .

Heaters on t h e piping adjacent t o FV-104, lo5 and 106 a r e on

a t a l l times during r e a c t o r operation. off t h e cooling gas flow.

A valve i s thawed by c u t t i n g

While freezing and thawing times a r e not

c r i t i c a l i n t h e operation of the

t h e observed time i s less

than 10 minutes with e l e c t r i c power a v a i l a b l e and less than 20 min when relying only on t h e residual heat i n t h e system. A cooling gas flow of 15 scfm through t h e cooling shroud w i l l

f r e e z e a salt plug i n less than 30 minutes.

When t h e temperatures

of t h e shoulders of t h e valve are indicated t o be l e s s than 750oF, t h e cooling gas flow i s reduced t o about 3 scfm t o hold t h e plug frozen.

Should t h e temperature climb t o about 820oF, t h e high flow

rate w i l l be resumed. i

If t h e temperature f a l l s below 6 5 0 v , t h e

gas flow w i l l be stopped a l t o g e t h e r t o prevent t h e formation of t o o l a r g e a frozen zone.

5.6.5.6

Freeze Valves 107, 108, 109, 110, 111. and 112. These

freeze valves a r e i n s t a l l e d i n salt t r a n s f e r l i n e s i n t h e f u e l d r a i n

tank and fuel processing c e l l s .

Although d i r e c t maintenance i s not

possible i n t h e d r a i n tank c e l l , FV-107, 108 and 109 were not provided

- I

UNCLASSIFIED ORNL-DWG. 64-6899

THERMOCOUPLES

COOLING GAS OUTLET

FIG. 5.32 FREEZE VALVE I N LINES 107,108 ,109 & 110

. 200

UNCLASSIFIED ORNL-DWG. 64-6900

FIG. 5.33. FREEZE VALVE I N LINES 1 1 1 a 112

201

with removable heater and insulation sections, as were FV-104, lo5 and

106, which are a l s o i n t h e d r a i n tank c e l l , because t h e non-removable

type heaters were simplier and more economical t o i n s t a l l .

Lines

107, 108 and 109 are not e s s e n t i a l t o reactor operation, and, i n most cases, i f a l i n e f a i l s t o t h a w properly, an alternate route can be used f o r t r a n s f e r of t h e s a l t .

A f u r t h e r consideration i s

t h a t t h e heaters a t FV-107, 108 and lo9 are seldom used, t h e valves remaining i n t h e deep frozen condition f o r long periods, and could be reasonably assumed t o require no maintenance during t h e l i f e of t h e MSRE c

The freeze valves i n t h e sealed drain tank c e l l use c e l l atmosphere

gas f o r cooling whereas FV-110, 111 and 112 are i n t h e f u e l processing c e l l and use a i r as t h e coolant. A s may be noted i n Figure 5.32, freeze valves 107, 108, lo9 and 110 have pots, o r reservoirs, on each side of t h e valve.

Freeze valves

FV-111 and 112 have a pot on one side only as shown i n Figure 5.33. The t r a n s i t i o n from 1/2-in. pipe s i z e t o t h e 1-1/2-in.

NPS freeze valve

section i s made a t t h e reservoirs. The dimensions of t h e f l a t t e n e d s e c t i o n of 1-1/2-in. as described f o r FV-103, Section 5.6.5.4,

above.

pipe are

The construction

of t h e cooling gas shrouds, t h e freezing and thawing times, and t h e thermocouple locations, are e s s e n t i a l l y t h e same as l i s t e d f o r FV-104 i n Section 5.6.5.5, L

above, and i n Table 5.11.

The heat f o r thawing of freeze valves lo7 through 112 i s conducted

along t h e pipe walls from t h e permanently-installed curved-plate ceramic pipe l i n e heaters on each s i d e of t h e freeze valve section.

The pipe

l i n e heaters are described and l i s t e d i n Section 5.6.6, following.

5.6.5.7

Freeze Valves 204 and 206.

These two freeze valves

are located i n t h e drain and f i l l l i n e s f o r t h e coolant-salt system and thus are not part of t h e primary c i r c u l a t i n g system.

They are

described here, however, t o complete t h e section on freeze valves. Both freeze valves are located i n t h e coolant c e l l , and both must be t h a w e d t o completely d r a i n t h e coolant-salt c i r c u l a t i n g system.

The f l a t t e n e d section of 1-1/2-in.

U i

pipe a t each freeze valve

i s t h e same as described f o r FV-103, Section 5.6.5.4.

The 1500-w

ORNL-DWG. UNCLASSIFIED 64-6901

FIG. 5.34. FREEZE VALVE I N LINES 204 8 206

G 11

'* (1

203 (at 110 v) Calrod heater u n i t i s i d e n t i c a l t o t h e one used on FV-103 (see ORNL Dwg E-GG-C-40

except t h a t t h e f l a t sides of t h e valves

a r e i n t h e horizontal plane and t h e heaters a r e applied from t h e side, FV 204 and 206 being approchable f o r d i r e c t maintenance a short time a f t e r reactor shutdown.

Curved-plate ceramic heaters a r e applied

t o t h e process piping on each side of t h e freeze valves, as shown on Dwg E-MM-Z-47489.

The thermal i n s u l a t i o n on t h e outside of t h e

l i n e heaters i s 3-in. of Careytemp 16OOoF ( P h i l i p Carey Mfg. Company). No thermal i n s u l a t i o n i s used around t h e center sections of t h e freeze

valves. No cooling gas shrouds a r e used.

The cooling a i r i s supplied

through t h e 3/4-in. l i n e s 906 and 907, each of which branches a t a t e e beneath i t s freeze valve i n t o two 3/8-in.

s t e e l pipes discharging

about 5/8 i n . from the t o p and bottom outside surfaces of t h e valve. See ORNL Dwg D-GG-E-41885

and Figure 5.35.

Two thermocouples a r e welded on t h e side of t h e center of t h e f l a t t e n e d section of each valve, and two a r e applied t o each shoulder. I n addition, single couples a r e i n s t a l l e d about 5 i n . upstream and downstream of each valve, and two a r e on t h e reservoir pot located between t h e two valves.

Thermocouple locations a r e shown on ORNL

DWg D-HH-B-40543. L

h A

When t h e valves a r e t o be thawed t h e cooling a i r supply i s stopped and t h e center heater i s turned on u n t i l t h e temperature measured a t t h e center of t h e valve i s greater than 1,000 A frozen valve w i l l thaw i n l e s s than 5 minutes.

- 1,1OO?F.

Without e l e c t r i c

power t h e valves w i l l t h a w i n l e s s than 25 min, by conduction of heat, and will remain thawed f o r 30 min o r more. The center heater, i f on, i s turned off before t h e valves a r e t o be frozen.

A cooling flow of 25 scfm of a i r w i l l freeze a s o l i d

salt plug i n l e s s than 1 5 min i n e i t h e r FV 204 or 206.

After t h e

temperatures of t h e shoulders of t h e valves reach about 750oF, t h e a i r flow i s reduced t o a holding r a t e of 5 scfm.

Should t h e tempera-

t u r e of t h e center of t h e valve climb above 75OoF t h e high a i r flow r a t e w i l l be resumed.

Below 6 5 0 0 ~t h e valves a r e deep frozen and

a l l a i r flow i s cut o f f .

204

Fig. 5.35.

Removable Heater for 5-in. Pipe.

205

5.6.6

Pipe Insulation and Heaters

5.6.6.1

General Description and Design Considerations.

salt-containing l i n e s i

All

he MSRE a r e thermally insulated and provided

w i t h e l e c t r i c a l heaters capable of maintaining t h e salt above t h e

liquidus temperature of 850oF. The heaters can be broadly c l a s s i f i e d i n t o t h e removable and permanent types.

The former a r e defined as those w i t h t h e thermal

i n s u l a t i o n and heaters arranged i n t o an i n t e g r a l u n i t that can be reI

moved and replaced by remotely-operated tooling as i l l u s t r a t e d i n Figure 5.35.

The types, which use more conventional materials and

methods of i n s t a l l a t i o n , a r e defined as those which would require d i r e c t approach f o r maintenance, although i n some instances t h i s would not be possible because of t h e a c t i v i t y l e v e l .

A l l such per-

manent heaters have spare heating elements i n s t a l l e d and connected ready f o r use except f o r minor out-of-cell changes. Some of t h e heaters a t t h e more inaccessible sections of piping have excess i n s t a l l e d capacities s o that they may be operated a t reduced voltage t o promote longer heater l i f e .

I n general, v e r t i c a l

l i n e s require about twice t h e heater capacity needed f o r horizontal pipes.

The heaters a r e supplied w i t h e i t h e r single phase 115-v,

single phase 208 and 23O-v, o r three-phase 208-v power, and some a r e connected i n s e r i e s and some i n p a r a l l e l , a l l as d i c t a t e d by t h e heater requirements and t h e nature of the e l e c t r i c a l supply equipment already on hand i n Building 7503 at the start of the MSBE p r o j e c t . The maximum amperage, t o t a l power per heater, and t h e watts per f t of pipe length, as l i s t e d on %he drawings and i n Table 5.12,

a r e based on the current-carrying capacity of t h e e l e c t r i c a l supply equipment and not upon t h e power that can be delivered t o each pipe section without excessive heating of t h e materials.

Such values

must be determined i n t h e f i e l d during preliminary t e s t i n g . o f t h e reactor.

The thermal i n s u l a t i o n can be divided i n t o (1) t h e metallic, multiple-layer r e f l e c t i v e type, and (2), t h e low thermal conductivity ceramic f i b e r o r expanded s i l i c a types.

The r e f l e c t i v e i n s u l a t i o n

206 has t h e important c h a r a c t e r i s t i c of not dusting, and i s used on a l l salt

l i n e s i n t h e r e a c t o r c e l l , with t h e exception of l i n e 103. The low conductivity types, as i n s t a l l e d , have a lower heat l o s s per f t of pipe. I n s e l e c t i n g t h e materials, consideration was given t o t h e resistance , t o r a d i a t i o n damage, accumulation of long-lived induced a c t i v i t y , and t o compatability with other materials i n t h e system. removable heaters use r e f l e c t i v e type i n s u l a t i o n . a t FV-104, lo5 and 106 use t h e ceramic f i b e r type).

Almost a l l t h e

(The removable heaters Almost a l l per-

manent heaters use expanded s i l i c a i n s u l a t i o n . A t least one thermocouple i s provided on t h e piping f o r each

heater unit.

Anticipated "cold spots" i n t h e piping have a d d i t i o n a l

couples. With t h e exceptions noted below, a l l t h e pipe l i n e heaters on t h e

portions of t h e f u e l and coolant-salt piping within t h e r e a c t o r c e l l

are of t h e removable type.

See Table 5.12.

These heaters have

resistance wire embedded i n f l a t ceramic p l a t e s and a r e arranged a t t h e t o p and s i d e s of t h e piping.

All t h e removable heaters i n t h e

reactor c e l l use multi-layer r e f l e c t i v e type i n s u l a t i o n . The v e r t i c a l l e g of piping i n l i n e 102 j u s t below t h e primary

heat exchanger i s very d i f f i c u l t t o reach w i t h remotely-operated tools.

The heaters f o r t h i s s e c t i o n a r e a t u b u l a r type strapped

t o t h e pipe.

A s e t of spare heater elements i s a l s o i n s t a l l e d .

This portion of piping would be removed with t h e heat exchanger i f r e p a i r s a r e needed.

These heaters on l i n e 102 have r e f l e c t i v e

. &

type i n s u l a t i o n . The portions of l i n e s 100 and 102 that pass through t h e thermal s h i e l d of t h e r e a c t o r a l s o have removable type heater-insulation u n i t s ,

as described above, but since access t o them would require l i f t i n g of t h e thermal s h i e l d plugs, each ceramic heater element i s provided with

a duplicate s e t of resistance wires i n t h e p l a t e s . Line lo3 i s heated by passing an e l e c t r i c current through t h e pipe w a l l i t s e l f .

Non-removable, expanded s i l i c a i n s u l a t i o n i s applied

over t h e resistance-heated length, including t h e portion i n s i d e t h e d r a i n tank c e l l .

See Section 5.6.6.2,

following.

207 . c

Lines 104, lo5 and 106 i n t h e f u e l - s a l t drain tank c e l l have removable heater-insulation u n i t s such as those used i n t h e reactor c e l l . The heaters on l i n e s 107, 108 and lo9 i n t h e d r a i n tank c e l l see l i t t l e service since t h e freeze valves i n these l i n e s a r e deep frozen most of t h e time.

I n most part, these t h r e e l i n e s have permanent

tubular-type heaters.

Although they should be maintenance-free during

t h e l i f e of t h e MSRE, duplicate spare heaters a r e i n s t a l l e d .

The

portion of t h e f u e l - s a l t t r a n s f e r l i n e 110 located i n t h e drain-tank c e l l a l s o has permanent tubular-type heaters, but, since t h i s l i n e i s used more o f t e n than 107, 108 and 109 (although s t i l l infrequently),

it i s provided w i t h two s e t s of spare heaters i n each pipe section. The s e c t i o n of l i n e 110 i n t h e f u e l processing c e l l , and l i n e s 111 and 112 i n t h i s c e l l , have permanent heaters and expanded s i l i c a i n sulation.

The equipment i n t h e f u e l processing c e l l w i l l require

decontamination before approach f o r d i r e c t maintenance, therefore spare heater elements a r e provided. Some sections of t h e piping i n l i n e s lo7 through 112, such as adjacent t o t h e freeze valves and a t t h e drain tank furnace walls, require a g r e a t e r concentration of heat than i s available from t h e tubular heaters.

Permanent curved-plate ceramic heaters a r e used

a t these points.*

See Table 5.12.

Direct maintenance can be used on t h e coolant-salt piping i n t h e coolant c e l l a short time a f t e r r e a c t o r shutdown.

Tubular-type

heaters a r e strapped t o t h e piping and covered with expanded s i l i c a insulation. c

The penetrations through t h e r e a c t o r containment vessel

w a l l f o r t h e coolant salt l i n e s 200 and 201 are provided with ceramic p l a t e heaters having spare heating wires.

These heaters,

and the low-conductivitythermal i n s u l a t i o n used with them, can be removed by manipulation from the coolant c e l l end of t h e penet r a t i o n , but they cannot be as r e a d i l y approached f o r d i r e c t maintenance as t h e other coolant c e l l equipment. Whe energy input on a, 1/2-in. NPS horizontal pipe i s about 750 watts/ft from a ceramic p l a t e type heater and about 200 watts/ft from a tubular type.

" z

208 5.6.6.2 methods:

Pipe Heaters.

The process piping i s heated by t h r e e

(1) ceramic p l a t e and (2)

t o t h e piping, and (3) e l e c t r i c current.

t u b u l a r type heaters applied

resistance heating of t h e pipe w a l l with an

The heaters are l i s t e d i n Table 5.12 f o r each of

t h e sections of piping.

The coolant-salt piping has been included

i n t h i s section t o complete t h e discussion of heaters and i n s u l a t i o n . . (1) Ceramic P l a t e Heaters.

These heaters c o n s i s t of nichrome

resistance wire embedded i n a ceramic p l a t e about 3/4 i n . t h i c k t o form either f l a t p l a t e s l/e-cylinder, t o fit the pipes.

o r 1/4-cylinder shapes curved

These "Thermoshell" elements, manufactured by

the Cooley E l e c t r i c Manufacturing Company (Indianapolis) a r e used

. r

i n a v a r i e t y of s i z e s , but t h e f l a t p l a t e s a r e t y p i c a l l y about 5 i n . wide x 12 i n . long.

(See heater schedules on O m Dwgs E-MM-

A-51601 and 40833, 51661 ) . As indicated i n Table 5.12, some ceramic p l a t e s have spare resistance wires. The ceramic p l a t e s are l a r g e l y composed of sodium atoms, but small amounts of thorium, leading t o 23%a a f t e r i r r a d i a t i o n , can

cause s i g n i f i c a n t a c t i v i t y i n t h e elements a f t e r long exposure. The resistance heating wires are primarily nickel and chromium with

small amounts of cobalt. Induced a c t i v i t y , due t o formation of 58C0 60Co from the n a t u r a l cobalt, probably w i l l refrom t h e nickel and e

s t r i c t d i r e c t handling of heater u n i t s removed from t h e r e a c t o r cell.

118 Y

(2)

Tubular Heaters.

These heaters a r e of t h e "Calrod" type,

as f'urnished by t h e General E l e c t r i c Company.

are 0.315 i n . OD. Table 5.12.

The Inconel sheaths

The lengths and c a p a c i t i e s vary, as shown i n

The No. 1 2 wire extension leads a r e i n s u l a t e d w i t h

ceramic beads, as shown i n d e t a i l on ORNL Dwg E-MM-B-5167.

(3) Resistance Heating. Drain l i n e lo3 i s heated by passing a heavy e l e c t r i c current a t 18 v through t h e pipe walls. The 25-kva 420/18-v transformer t o supply t h e current i s located i n t h e southwest corner of the d r a i n tank c e l l .

Leads from t h i s transformer a r e

connected a t about midpoint i n the l i n e , which i s i n t h e d r a i n tank c e l l near t o t h e transformer. t o each end of t h e l i n e .

The current flows from t h i s connection

E l e c t r i c a l connections a r e made about 12 i n .

Table 5.12.

Heater Number

Location

MSRE Pipe Line Heaters

Maximum Values Based on Elec. Supply System Equipment

Heater Length (in.)

Type'

11-7/16

Number Heaters

Total Watts

Watts per f t

16.5

3800

4000

Duplicate spare i n s t a l l e d

24.3

2800

6250

13.9 17.4

5000

2000

Connected with HlO2-3

4000

23.5

2700

3550 4100

2120

1275

Duplicate spare i n s t a l l e d

28.0

1840

1275

Duplicate spare i n s t a l l e d

1275 2400

Duplicate spare i n s t a l l e d

Voltsb

Amps

Remarks

RFACTOR CELL'

H100-1

R o u t l e t t o FFlOO

H100-2

FF-100 t o FP furnace

5-318

H101-1

FP t o FF-101

27-13/16

mol-2

FF-101 i n l e t

13-112

~101-3

HX i n l e t

5-112

H102-IA

V e r t i c a l l i n e from HX

Hl02-1B

V e r t i c a l l i n e from HX

H102-1C

Vertical l i n e from HX

m02-2~

Horizontal l i n e t o FF-102

11.1

1970 4000

Hl.02-2B

Horizontal l i n e t o FF -102

11.1

4000

2400

H102-3

Horizontal l i n e t o FF-102

11.1

4000

2000

Connected with H 1 0 1 - 1

H102-4

FF-102 i n l e t

3800

4000

Duplicate spare i n s t a l l e d

H200-1

Adjacent c e l l w a l l

11.7 16.5 17.4

4000

FF-102 t o R

H200-2

Cell wall t o FF-200

11.1

4000

2000

Connected with H2OO-3 & 4

H200-3

Cell w a l l t o FF-200

13.9

5000

2000

Connected with H200-2 & 4

H200-4

C e l l wall t o FF-200

3 3 3 6 6 6 6 6 6 6

2700

H102-5

8-3/16 11-7/16

11.1

4000

2000

Connected with H200-2 & 3

5000

2200

Connected with ~ 2 0 1 - 8

5000

2000

€1200- 5

C e l l w a l l t o FF-200

11200-6

C e l l wall t o FF-200

~200-7

C e l l w a l l t o FF-200

11200-8

Cell w a l l t o FF-200

13.9 13.9 13.9 13.9

4000

5000

2000

5000

2000

I -

Table 5.12. (continued)

Heater Number

Location

Heater Length (in.)

Maximum Values Eased on Elec. Supply System Equipment Typea

Amps

Total Watts

Watts per f t

6 6 6 6

11.1

4000

2400

11.1

4000

2400

11.1

4000

2000

Connected with H2Ol-3

19.2

4000

2075

Number Heaters

Volts

~ 2 0 0 - 9 ~ Wall t o FF-200

H200-10

Wall t o FF-200

H200-11

Adjacent FF-200 HX i n l e t

23-3/16 lo

3 6

26.9

3100

7500

19.2

4000

2075

3700

2000

H200-12

Remarks Connected with HZ'OO-gB,

4A & 4B

H201-1

Adjacent FF-201 HX s i d e .

23- 3/16

H201-2

Adjacent FF-201 HX s i d e ,

11 3/16

16.1

~201-3

5000

2000

Connected with H200-10

11.1

4000

2400 )

H201-4B

FF-201 t o c e l l wall

11.1

4000

2400 )

Connected with H200- A, B & ?B Connected with i200- A,

13.9

5000

2000

6 6 6 6 6 6 6 6

13.9

H201-4A

FF-201 t o c e l l wall FF-201 t o c e l l w a l l

11.1

4000

2000

13.9 13.9

5000

2000

5000

2000

Connected with H2OO-5

24.0

5000

2000

3 6 6 6

11.3

1300

1500

19.6

4500

1800

26.0

6000 4500

2400 1800

3 3 8

14.8 17.4

1700 2000

1950 2000

26.0

6000

2400

~201-5 ~201-6

FF-201 t o c e l l wall FF-201 t o c e l l wall

~201-7

FF-201 t o c e l l wall

~201-8

FF-201 t o c e l l wall

~201-9

FF-201 t o c e l l w a l l

9B % ?A

DRAIN TANK CELL LINE HEATER UNITSd

H104-1

A t FFT

10-112

H104-2

FFT t o FV-104

mo4-3

FFT t o FV-104

H104-4

A t FV-104

H104 5

FV-104 t o l i n e 103

1042

R104-6 HlO4-7

FV-104 t o l i n e 103

A t l i n e lo3

19.6

Duplicate spare i n s t a l l e d

. v

Table 5.12.

(Continued) Maximum Values Based on Elec. Supply System Equipment

Heater

Heater Number Hl.05-l

HlO5-2 H105-3 H105-4 ~106-1 ~106-2 ~106-3 H106-4 HlO7-l

Location A t FD-2

FD-2 t o FV-105

Number

Length (in.)

Typea

10-112

Heaters

3 6 6 3 3 6 6 3

FD-2 t o FV-105

30 30

A t FV-105

A t FD-1

10-112

FD-1 t o FV-106

A t FV-106 FV-106 t o l i n e 103

A t FFT

4 62

c2 T

2 2

c2 T

~108-2-1 FD-2 t o FV-108

32 4 4 4 44

~ 1 0 8 - 2 - 2 FD-2 t o FV-108

32 4 4 4 44

~107-2-1 FFT t o ~ v - 1 0 7

~107-2-2 FFT t o FV-107 H107-3,3B Adjacent flange x, p, Adjacent flange ~ 1 0 8 - 1 A t FD-2

~ 1 0 8 - 2 - 3 FD-2 t o FV-108 €1108-3~~3~ Adjacent flange -3C 3D Adjacent flange A t FD-1 HlO9-l HlO9-2-1 FD-1 t o FV-109 HlO9-2-2 FD-1 t o FV-109 H109-2-3 FD-1 t o FV-109 Hl09-3,3B Adjacent flange -3C,=;D Adjacent flange

cl C1

2 2

32 4 4

c2 c2

2 2

V o l t sb

Amps

115

230 115 115 230 230 115 57.5

11.3 19.6 17.4 17.4 11.3 19.6 26.0 8.7 4.35

l4O

7.26

230

140 )

Total Watts

Watts per f t

1300 4500 4000

1800 1600

2000

1300

1500

4500 6000

1800 2500

1000

250 750

750 187 187 750 750 750 185 185 185 750 750 750 185 185 185 750 750

280 250

57*5) 57.5) 57.5 140 ) 140 140 )

8*7 4.35

57'5) 57.5) 57.5 140 ) 140 140 ) 57.5) 57.5)

8*7 4.35

9.25

250 250 460 550 275 250

{

9.25

250 250 460 550 275 250

8'7

250

1500

Remarks

Duplicate spare i n s t a l l e d

Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d

Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d

Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d

Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d

Table 5.12. (continued)

Maximum Values Based on Elec. Heater Number

H110-1-1 H110-1-2 H110-2-1 H110-2-2 HllO-2-3

Location

FV-108t o l i n e 110 FV-109 t o l i n e 110 Adjacent FV-107 FV-107 t o c e l l wall FV-107 t o c e l l w a l l

HllO-3-1 FV-107 t o c e l l w a l l HllO-3-2 A t c e l l wall

Heater Length (in.)

Supply System Equipment Total Watts

Watts per f t

550 550 1600

185 185 230

1150 2500

750

230 230 500 500

Typea

Number Heaters

50 50

98 98 74

3 3 3 3 3 3

b Volts

l4O 140

Amps

7.9

Remarks Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d Two duplicate spares installed Two duplicate spares installed

Two duplicate spares installed

COOLANT CELL LINE HEATER UNITSe H2OO-13-1 CP t o sleeve H2OO-13-2 CP t o sleeve H200-13-3 CP t o sleeve H200-13-4 CP t o sleeve H200-13-5 CP t o sleeve

86 86 86 86

~200-13-6CP t o sleeve H200-14A,B Wall sleeve H200-14C,D Wall sleeve H200-14E,F Wall sleeve

12 12 12 12

c2 c2

12 12

c2 c2 c2 c2

H200-14G,H Wall sleeve H200-15A,B Wall sleeve

H201-1OA,B Wall sleeve H201-11A,B Wall sleeve H201-11C,D Wall sleeve H2Ol-lIE,F Wall sleeve

HgOl-llG,H Wall sleeve

T T T

12 12 12

c2 c2

2 2 2

2000

600

Duplicate spare i n s t a l l e d

600

600 600

Duplicate spare i n s t a l l e d

600

Duplicate spare i n s t a l l e d

5000 5000

5000

230

230 230

10.4

820 820 820 820 820 820

5000

600 600

Duplicate spare i n s t a l l e d

2 2

1500

Duplicate s p i r e i n s t a l l e d

1500

Duplicate spare i n s t a l l e d

2 2 2 2

600 600 600 600

600

Suplicate spare i n s t a l l e d

600

Duplicate spare i n s t a l l e d

600 600

Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d

B.!J

Table 5.12.

Heater Number

Location

Heater Length (in.)

(continued) Maximum Values Based on Elec. Supply System Equipment

Typea

Number Heaters

b Volts

Total Watts

Watts per f t

36 (83)

960 3200 3800 3800 3800 3800

640 640 640 640 640 640

16.3

1875 1875

275 275

11.9

1670 3280

400

2000

820

5000

820

5000

820

5000

820

5000

820

80 80

Duplicate spare i n s t a l l e d

3.3

470 470 462

185

Duplicate spare i n s t a l l e d

see next page

1375 1375

275 275

Duplicate spare i n s t a l l e d

Amps

Remarks

H201-12-1

Sleeve t o r a d i a t o r enclosure

32 74 86 86 86 86

I n r a d i a t o r enclosure

~201-13-2 I n r a d i a t o r enclosure

H201-12-2

~201-12-3

H201-12-4 ~201-12-5 ~201-12-6 ~201-13-1

H202-1-1

CR o u t l e t pipe

H202-2-1

CR t o CP

H202-2-2

CR t o CP

~202-2-3

CR t o CP

H202-2-4 ~202-2-5 ~202-2-6

CR t o CP CR t o CP

CR t o CP

H203-LA-lE* CDT F i l l l i n e

H2O3-m

CDT F i l l l i n e

~203-2

F i l l l i n e adjacent t o CM!

H204-1-1 H204-1-2

Line 201 t o FV-204 Line 201 t o FV-204

* Typical f o r LA through lE.

3 3

2 30 230

50 62 44 86 86 86 86

86 44 44 74 74

35 (80.0)

91 91 140

221

) 1 221 )

820

Duplicate spare i n s t a l l e d

Table 5.12. (continued)

Heater Number

Location

Heater Length (in.)

Maximum Values Based on Elec. Supply System Equipment Type'

Number Heaters

b ~

Line 201 t o FV-204

74 74

Line 201 t o FV-204

FV-204 & FV-206t o CM!

H204-2-2

2 2

221 ) 221 )

221 )

FV-204& FV-206t o CDT

-1- 1 ~205

Line 201 t o l i n e 202

H205-1-2

Line 201 t o l i n e 202

Line 202 t o FV-206 ~206-1-2 Line 202 t o FV-206

T T

2 2

244 ) 244 )

244 )

2 2

H204-1-3 H204-1-4

Line 201 t o FV-204

H204-1-5 H204-2-1

13206-1-1

~206-1-3 Line 202 t o FV-206 H206-1-4

Line 202 t o FV-206

~206-1-5 Line 202 t o FV-206 a

62 62 32

132 132

Total Watts

Amps

Volts

~~~

20.0

11.2

20.2

244 1 244 )

Remarks

~~~

275

Duplicate spare i n s t a l l e d

1375 275 687.5 275

Duplicate spare i n s t a l l e d

510 850

170 170

Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d

1100

150

Duplicate spare i n s t a l l e d

650

140

Duplicate spare i n s t a l l e d

1120 1120

280 280

Duplicate spare i n s t a l l e d Duplicate spare i n s t a l l e d

1120 1120

280 280

Duplicate spare i n s t a l l e d

1120

280

Duplicate spare i n s t a l l e d

1375 28

Watts per f t

Duplicate spare i n s t a l l e d

C removable heater u n i t w i t h 3 segments ( t o p and each s i d e ) , ceramic elements. Duplicates have double element Removable heater u n i t , t h r e e f l a t ceramic elements ( t o p and s i d e ) . C2 Fixed 90" curved ceramic i n each segment. Cl t u b u l a r heaters, non-removable.* TR t r i a n g u l a r , non-removable. elements. T

bSingle phase unless otherwise indicated. C

* Each tubular heater includes a 7-in. non-heated length a t each end.

Reference Drawing E-MM-A-51601.

'Reference e

Drawing E-MM-A-51661.

Reference Drawing E-MM-A-40833.

The w a t t s / f t i s based on heated length.

215

from t h e i n t e r s e c t i o n w i t h l i n e 104 and j u s t i n s i d e t h e reactor furnace on t h e other end. t h e pipe.

These connections a r e made by welding t h e l u g t o

The r e t u r n e l e c t r i c a l connection from t h e pipe ends i s

4 wire mineral-insulated cable 0.699 i n . OD l a i d i n s p e c i a l brackets about 4 i n . above t h e l i n e lo3 routed along t h e pipe as a single-No.

insulation.

See ORNL Dwg E-MM-A-56240.

5.6.6.3 Thermal Insulation.

Primary considerations i n t h e

s e l e c t i o n of t h e pipe l i n e i n s u l a t i o n were t h e tendency of t h e materials t o dust, t h e resistance t o radiation damage and longterm a c t i v a t i o n , t h e thermal conductivity, and t h e presence of organic materials causing thermal d e t e r i o r a t i o n o r incompatability w i t h other materials i n t h e system.

The multi-layer r e f l e c t i v e type of i n s u l a t i o n presents fewer r

dusting problems as compared t o t h e low-conductivity type and i s used almost exclusively i n t h e reactor c e l l , although t h e s t a i n l e s s s t e e l does contain some cobalt which w i l l become radioactive.

The

r e f l e c t i v e u n i t s have a higher heat l o s s than t h e l a t t e r , however, as i l l u s t r a t e d by t h e f a c t that horizontal sections of

5 i n . pipe

with r e f l e c t i v e i n s u l a t i o n require, on t h e average, about 2,000 w a t t s / f t of energy input whereas similar pipe sections with expanded s i l i c a i n s u l a t i o n require about 600 w a t t s / f t ,

Some compromises were necessary i n s e l e c t i o n of t h e low-conduct i v i t y i n s u l a t i o n i n t h a t t h e good thermal conductivity and mechanical properties must be coupled with good resistance t o spread of a i r borne contamination.

Many mineral wool f i b e r s contain s i g n i f i c a n t cobalt o r

organic materials.

Both t h e ceramic f i b e r and t h e expanded s i l i c a types

s e l e c t e d f o r use i n t h e MSRE a r e f i r e d a t 1200'F

f o r about four hours

before i n s t a l l a t i o n t o d r i v e off small amounts of v o l a t i l e s u l f u r and chloride compounds.

The types of i n s u l a t i o n and t h e thicknesses used

are l i s t e d i n Table 5.13. (1) Reflective Insulation.

Reflective i n s u l a t i o n i s used i n a l l

but a few of t h e removable heater u n i t s .

The t y p i c a l r e f l e c t i v e u n i t ,

as manufactured by t h e Mirror I n s u l a t i o n Company (Lambertville, New Jersey) c o n s i s t s of a removable section, which surrounds t h e t o p and s i d e s of t h e pipe, and a permanent bottom section which

Table 5.13 Line Number

Line Size i n . NPS

THERMAL INSULATION ON MAJOR MSRE SALT PIPING Insulation* Phickness, i n .

Location

Removable

Remarks

Yes

Reflective

Yes

Reflective

Reactor c e l l

4 4 4

Yes

Reflective

V e r t i c a l s e c t i o n beneath heat exchanger i s non-removable.

Reactor and f u e l DTC*

Expanded s i l i c a

Pipe i s resistance-heated.

Fuel d r a i n tank c e l l

4 4 4

Yes

Reflective

Yes

Reflective

Removable u n i t s a t f r e e z e valves have ceramic f i b e r insulation.

Yes

Reflective

3 3 3 3 3 3

Expanded s i l i c a

100

Reactor c e l l

101

Reactor c e l l

102 103 104 105 106

Fuel d r a i n tank c e l l

107 108

Fuel drain tank c e l l

109

Fuel d r a i n tank c e l l

110

Fuel DTC and FPC*

111

Fuel processing c e l l

112

Fuel processing c e l l

200

Reactor c e l l

Reflective

Reactor c e l l

4 4

Yes

201

Yes

Reflective

202

Coolant c e l l

Expanded s i l i c a

203 204

Coolant c e l l

Expanded s i l i c a

Coolant c e l l

3-112

Expanded s i l i c a

205 206

Coolant c e l l

Expanded s i l i c a

Coolant c e l l

3-112

Expanded s i l i c a

Fuel d r a i n tank c e l l Fuel d r a i n t a n k c e l l

* DTC = Drain tank c e l l ;

I n s u l a t i o n outside r e a c t o r c e l l

i s non-removable exp'd. s i l i c a .

4 i n . i n thickness

FPC = Fuel processing c e l l .

**For i n s u l a t i o n d e t a i l s see ORNL Dwg E-MM-Z-56235.

c; '

217

k/ c

i s attached t o t h e s t r u c t u r e below t h e pipe and supports t h e t o p section. The heater p l a t e s a r e mounted i n c l i p s i n t h e t o p section and are removable with it. Application of heat t o only t h e t o p and sides was demonstrated t o give s a t i s f a c t o r i l y even temperature d i s t r i b u t i o n t o t h e pipe contents.

(The thermocouples f o r measuring t h e pipe w a l l

temperature a r e , f o r t h e most past, attached t o t h e bottom of t h e p i p e ) . S t a r t i n g a t t h e inside, t h e f i r s t l a y e r of r e f l e c t i v e metal i s

16 gage 310 s t a i n l e s s s t e e l . The next l a y e r i s a sheet of pure s i l v e r 0.002 i n . t h i c k .

The following nine l a y e r s a r e 321 s t a i n l e s s s t e e l ,

0.006 i n . thick, arranged about 0.36 i n . a p a r t t o provide a t o t a l

thickness f o r t h e assembly of about 4 i n . gage 304 s t a i n l e s s s t e e l .

The outside surface i s 18

The removable u n i t s have a l i f t i n g eye a t

t h e t o p f o r handling with remote tooling. L i f e tests on t h e heater-insulation u n i t s covering s i x months of continuous operation a t 1400OF indicated about a 1 6 increase i n t h e heat l o s s due t o change i n t h e emissivity of t h e surfaces. showed good r e s i s t a n c e t o warping. (2)

Ceramic Fiber Insulation.

The u n i t s

(See p 30 ref 117). "Fiberfrax", a product of t h e

Carborundum Compny (Niagra Falls) i s used i n t h e paper form i n t h e freeze valve cooling gas shrouds, and i n t h e blanket and bulk forms,

a t such points as t h e removable heaters a t FV 104, 105 and 106. The ceramic f i b e r i s about 5l.$ A 1 0 and 4 7 . q Si02 (by weight) and i s

2 3 recomended f o r temperatures up t o 2300%'.

The thermal conductivity

of t h e blanket and bulk forms, when packed t o a density of 6 l b s / f t 3 ,

i s 1.24 Btu-in./hr-V-ft2

a t l O O O V and 1.89 a t 1400'F.

The Fiber-

f r a x paper used i n t h e MSRE i s Type 970-JH, which contains no organic binder.

The paper has a thermal conductivity of 0.73 Btu-in./hr-ft2-'F

a t 1,000'F

and 0.95 a t 1400OF.

neutron f l u x of

7 x lo1'

Activation analyses a f t e r 16 hrs i n a

n/cm2-sec indicated that t h e 14'I,a,

with a

with 15-h half-life measured 24 hours a f t e r i r r a d i a t i o n , gave 2.72 x 102 d i s i n t e g r a t i o n s per sec-gm and 40-h h a l f - l i f e , and t h e 24Na,

1.87 dis/sec-gm, respectively.

(See p 48 ref 108).

These values

i n d i c a t e r e l a t i v e l y good r e s i s t a n c e t o long-lived a c t i v a t i o n

h-, 3

as compared t o most inorganic, low-dusting, high-temperature i n s u l a t i o n w i t h low thermal conductivities.

218

(3) Expanded S i l i c a Insulation.

The expanded s i l i c a insulating material used i n the MSRE i s reinforced with inorganic fibers and has the trade name "Careytemp 1600", and i s marketed by the Philip Carey Manufacturing Company (Cincinnati) The thermal conductivity i s l i s t e d 2 as 0.76 Btu-in./hr-ft -"F at 1,OOO"F. It i s recommended f o r use up t o 1600°F. It contains no inorganics, has a low hygroscopicity, and has good resistance t o dusting. Irradiation w i t h neutrons f o r 16 hrs at a f l u x of 7 x 10l1 n/cm2-sec gave a c t i n t i o n s of 3.06 x 103 dis/sec-gm

L€J I

f o r t h e 40-h half-life 140La, 1.12 x 10 dis/sec-gm f o r the 85-d 46Sc, (See 5.02 x 103 f o r t h e 45-d 59Fe, and 8.57 x 107 f o r the 15-h 24Na. p 48 ref 108). The insulation i s applied t o the piping over the tubular heaters i n 1/2-cylinder molded shapes. It i s then covered with asbestos finishing cement and glass cloth, and a bonding adhesive t o give a glazed finish.

5.6.6.4

Pipe Line Thermocouples. Since the pipe l i n e thermocouples are intimately associated w i t h i n s t a l l a t i o n and operation of t h e heaters and t h e insulation, they are b r i e f l y described here. See Part I1 f o r a detailed description of the couples and the associated circuitry. Thermocouples are installed a t t h e bottom of the pipe a t each heater unit i n t h e reactor and drain tank cells, and a t the more important "cold spots." These spots, such as where pipe hangers are attached, may have lower than average temperatures and are therefore of particular interest. As shown on Dwg E-HA-B-41713, and i n t h e thermocouple tabulation, ORNL Dwg D-AA-B-40511, many of the couples on the reactor c e l l piping a r e provided w i t h spares. The coolant-salt piping also has a thermocouple a t each heater unit and a t some of the cold spots, but very f e w spares are provided since t h i s piping i s accessible f o r maintenance. An exception t o t h i s is l i n e s 204 and 206, which have spare couples a t several points because of the importance of knowing the condition of the l i n e . The penetrations of the coolant-salt piping through the reactor containment vessel w a l l have thermocouples on t h e bottom of the pipe spaced 12 i n . apart. Each of these points i s provided w i t h a spare couple. See ORNL Dwg E-HH-B-40537.

- I

219

I n a l l cases, except as noted below, t h e thermocouples a r e mineral-

insulated chromel-alumel wires i n a 1/8-in. OD Inconel sheath.

The

couple junction i s welded t o t h e end of t h e sheath, as described i n

ORNL Spec MSR 63-40, and i l l u s t r a t e d on ORNL Dwg D-GG-C-55509. An

INOR-8s t r i p , 1/4-in. wide x 0.015 i n , thick, i s shop-welded t o t h e end of t h e sheath.

With t h e exception of t h e 1/2-in. NPS piping, t h e

ends of t h i s s t r i p a r e field-welded t o pads, formed by welding, on t h e process piping. L

The ends of t h e couples on 1/2-in. piping a r e

attached t o a 1/8-in. high projection, formed by welding, on t h e outside of t h e pipe, and t h e thermocouple sheath i s strapped t o t h e pipe.

The same s t r a p s a r e used on a l l pipe s i z e s where it i s necessary t o f a s t e n t h e sheath t o t h e pipe a t points other than a t the ends.

The

INOR-8banding material i s 1/4 i n . wide and fastened by a patented

"Wraplock" process.

The duplex thermocouple sheaths described above a r e not used on t h e r e a c t o r vessel discharge piping a t t h e f u e l pump i n l e t , l i n e 100. T h i s s e t of t h r e e couples, and t h e associated spare, f o r measuring t h i s important temperature, use two single-wire 1/16-in. OD Inconel

sheaths, w i t h t h e welded couple junction made a t t h e ends.

Another

s e t of these "safety" couples i s used i n l i n e 202 a t t h e r a d i a t o r outf

let.

These single-wire couples a l s o use 1/16-in. OD sheaths but a r e

not attached i n t h e manner described above.

Removable thermocouples

are used i n themowells a t t h i s point (202 A - 1 through D-1) and a t

t h e thermowell i n the r a d i a t o r i n l e t , l i n e 201, t o measure t h e A t i n t h e coolant-salt flow through t h e r a d i a t o r .

The thermocouples f o r l i n e lo3 a r e a s p e c i a l case i n that an e l e c t r i c current flows through the pipe w a l l .

The thermocouple

sheath i s i n s u l a t e d from t h e pipe w i t h cerardc beads except f o r about 1/4 i n . a t t h e end.

The junction i s a n ungrounded type.

220

60 FuELDRA3[mTAM(SYSTR4 6.1 General Description and Layout The MSRE primary circulating system i s provided with two f u e l drain tanks and a flush s a l t tank,

The drain tanks are used t o store the f u e l

salt when it i s drained f r o m the reactor. Either of the two drain tanks can store the entire salt content of the primary circulating system. The flush salt tank is used t o store the salt, which i s circulated through the primary system t o clear it of oxides and other contaminants before the enriched s a l t i s adaed. (In addition, a f u e l storage and reprocessing tank i s located in the f u e l processing cell. This tank i s described i n the chemical processing portion of t h i s report, Part VII.) The geometry of the fuel-salt drain tanks is such that the concent r a t i o n of uranium i n the MSRE fuel s a l t (see Table 2.1) cannot produce a c r i t i c a l mass under any conditions. l l - 9 A f o e o l d increase in constudies have centration wouldbe necessary f o r c r i t i c a l i t y . Altho# that i n equilibrium cooling of salt mixtures the last indicated phase t o freeze may contain about three times the uranium concentration in the o r i g i n a l mixture, it is unlikely that the salt i n the tanks w i l l freeze, i n that this would require an e l e c t r i c power outage of more than 20 hr, o r that gross segregation of the concentrated phase could take place in a large-sized tank having so many thimbles on which ,initial The risk of c r i t i c a l i t y can be solidification would take place. eliminated altogether by dividing a fuel-salt charge between the two drain tanks. One tank w i l l be kept empty f o r this contingency. The two drain tanks and the flush s a l t tank are located in the drain tank cell, which is j u s t north of the reactor c e l l and connected t o it by a short 36-in.-diamtunnel. The drain tank c e l l i s constructed of heavily reinforced concrete, lined with stainless steel, and of the general dimensions given i n Section 4.3.2. The layout of the equipment i n the c e l l i s indicated in Figs. 4.4 and 4.5, and i s shown i n more d e t a i l in ORML Dwg. Ea-D-41512. !be arrangement was primarily influenced by the requirement that'all maintenance operations be performed f r o m overhead. Other considerations were t h e arrangement and f l e x i b i l i t y of the piping, and the

221

relative elevations so that the reactor could drain by gravity. The drain l i n e from the bottom of the reactor vessel, l i n e 103, branches inside the drain tank c e l l into three l i n e s which lead t o the two drain tanks and t o the flush salt storage tank. The f u e l s a l t l i n e s from these tanks, which permit interchange of salt with t h e fuel procesaing area, conibine into a single pipe, l i n e 110, before leaving the drain tank c e l l , Each of the six l i n e s mentioned has a freeze valve, as described i n Section 5.6.5 , The three branches of the reactor drain and f i l l line, l i n e 103, reduce f r o m 1-1/2-in. sched-40 t o 1-in. pipe where each passes through the tank heating furnace and makes a loop about 44 in. i n diameter, encompassing about 340°, then enters the respective tank through the top head. This loop provides the flexdbility needed t o prevent pipe reaction forces due t o thermal expansion from overly affecting the tank weigh c e l l s used t o Judge the salt inventory. The loops also reduce the thermal stresses i n the piping. Each tank i s provided with an e l e c t r i c a l l y heated f'urnace t o maint a i n the contents i n a molten condition, Portions of the salt l i n e s are provided w i t h removable heater units and others have permanently installed Calrod-type heating units, as described i n Section 5.6.6, The reactor drain l i n e lo3 i s unique i n the reactor system i n that it i s heated by passage of an e l e c t r i c current through the pipe w a l l i t s e U . The drain l i n e is heated by t h l s method from a point at the reactor furnace wall t o about 1f t from the branch point insiae the drain tank c-ell, a distance of about 64 ft, and requires about 17 kw. The 25-lrva high-current elect r i c a l transformer, 420 t o 18 v, i s located i n the drain tank c e l l (see Section 19,7.3,2). It has been-estimated that, on opening of' the freeze valve i n l i n e 103, eleven t o thirteen minutes are required for sufficient salt t o drain fromthe primary system t o leave the reactor core region one-fourth ' About 30 min i s required for all the s a l t t o drain. The two drain tanks are each provided with a heat se~llovalsystem of This rate of heat &:issipation i s required f o r the first 124 80 hr a f t e r shutdown; about 50 kw i s needed fn 8s- t o 500-hr period. The heat removal system consfetB of 3,2 thixtibles, l o g in, i n diameter, 108-kw capacity.

222

immersed in the salt, and containing bayonet tubes in which water is

evaporated. The steam f r o m the tubes i s collected i n a steam drum located above each tank and piped t o condensers outside the drain tank cell. The condensate is returned by gravity i n a closed cycle. Transfer of the salt from one part of the system t o another is accomplished by pressurization with helium gas. The gas is admitted a t the top of the tanks through lines 572, 574, ana 576. AI.I. salt lines enter near the top af the tanks and have dip tubes t o the bottom. The tanks are prodded with weigb cells, as described in Part II. Provisions are made t o cut the piping t o permit replacement of the drain tanks and freeze valves. L h e s 104, 105, and 106 can be cut and rejoined l a t e r by a brazed-on sleeve applied a t the cut, using remotely operated tooling developed a t O m . This special equipment is described i n Part X. Lines 107, 108, and 109 have one-half of a l5O-lb, slip-on, ring-joint flange installed I n them. If a tank i s removed, the l i n e leading t o the flange involved is cut on the tank side of the flange. The replacement tank can have a matilag flange, or, as seems most likely, a blank flange can be bolted in place. If the l i n e i s blanked off, lines 104, 105, and 106 can be used t o interchange the s a l t between the tanks by manipulation of the appropriate freeze valves. The salt can then be transferred t o the f u e l storage tank through whichever of lines 107, 108, and l O g remain. The steam drum liquid-level lines have cone-sealed, single-bolt, yoke type disconnect couplings, which were designed and developed a t OIWL, and are described i n Part II. The gas l i n e s have special 4-bolt flanged disconnect joints installed i n the horizontal position t o f a c i l i t a t e remote maintenance. Detailed discussions of the maintenance procedures are given in Part X. 6.2

Flowsheet

The process flowsheet f o r the f u e l drain tank system is shown in Fig. 6.1 (ORmlL Dwg. D-AA-A-40882). More detailed information is available in the data sheets,16 the l i n e schedules,17 and the thermocouple tabuThe instrunents and controls are described lation, ORNL Dwg. D-AA-B-405ll.

u c

s’

223

C w

I nHOT LUG

;-.o-ss

DRAIN TANK CELL

-7;

FUEL PUYP

TO AUXILIARY

CHARCOAL OED

I I I

I ELECTRICAL SERVICE AREA

FUCC

FLUSW

11"

H I S I WEATER CONTROL

CIRCUIT

I I I i

THIS DRAWING REI

AS BUlL CHANGES DATE

9-18-64

O I U R I W . NATIONAL U.oILIoI*

FUEL DRAIN TANK SYSTEM PROCESS FLOW SHEET M.S.R. E. A

DAA-A~O~BZ-C

224

i n Part XI, and operating procedures are given i n Part VIII.

As shown i n the flowsheet, Fig. 6.1, the f u e l drain tanks, FD-1 and FD-2, and the f u e l f l u s h tank, FET, a r e provided with 1 in./l-l/2-in. sched-40 l i n e s 106, 105, 104, respectively, t o permit interchange of t h e f u e l salt with the primary circulating system.

Each of these three l i n e s

includes a freeze valve f o r positive, non-modulating control of the s a l t flow.

The freeze valves a r e simply f l a t t e n e d sections of 1-1/2-in.

sched-

40 pipe, which can be e i t h e r heated by e l e c t r i c heating elements o r cooled by a j e t of c e l l atmosphere gas.

The freeze valves a r e described i n

Section 5.6.5.5 The main supply f o r t h e freeze valve cooling gas i s the 2-in. sched-40 l i n e 920, which branches i n t o 3/4-in. freeze valve.

l i n e s 908, 909, 901, t o supply each

These three l i n e s a r e provided with control valves and remote

hand-operated regulators. A short, v e r t i c a l cylinder of 4-in. pipe i s included i n t h e 5 a l t piping

on the tank side of each valve t o form a reservoir which assures t h a t the freeze valve section w i l l be f i l l e d with s a l t .

Either freeze valve FV-105

o r 106 is always thawed during operation of the reactor t o permit ready drainage of the circulating system i n t o one of t h e drain tanks. The other valve i s operated i n a frozen condition such t h a t t h e heat stored i n the adjacent piping and heater box will cause t h e valve t o thaw on loss of heater e l e c t r i c a l power and coolant flow.

A l l other valves on t h e d r a i n

tank system, FV-lo7 through 110, a r e deeply frozen and w i l l remain so even on loss of power.

The times required f o r freezing and thawing a r e

indicated i n Table 5.11.

Helium gas pressurization and vent l i n e s control t h e t r a n s f e r of s a l t from one p a r t of the system t o another. The tops of the drain tanks and f l u s h tanlrs are vented t o the top of the f u e l - s a l t circulating pump bowl through the 1/2-in.

schcd-40 pipes, l i n e s 544,

545, and 546.

Each of

these l i n e s contains a pneumatically actuated control valve which can be positioned from a remote location by a hand-operated regulator. three l i n e s combine t o form 3/4-in.

The

l i n e 521 leading t o t h e putnp bowl.

This vent l i n e not only permits t r a n s f e r of the cover gas a s t h e s a l t i s

being exchanged between the primary c i r c u l a t i n g system and t h e storage

...

. ._"

225 tanks, but provides a large gas "cu&hionwso that the overpressure i n the

pump bowl can be more evenly maintained.1'

The gas l i n e fromthe top of each tank i s connected t o the charcoal beds through lines 573, and 577. These lines contain control valves with remote hand regulators and combine t o form 1/2-in. l i n e 561 leading t o the off-gas system. Helium f o r the cover gas and pressurization is supplied a t about 40 psig through the 1/2-ine l i n e 517 t o the pressure control valve PCV-517,

5n,

which delivers the gas a t about-30 psig t o the branch-pipes, lines 572, 574,

and 576, leading t o the top of each salt storage tank. A flow r e s t r i c t o r i s installed upstream of PCV-517to l i m i t the rate a t which the f u e l can be transferred t o the reactor. When the reactor system i s about twothirds f W l , t h i s rate i s 1/2 ft3 of s a l t per minute. The three branch lines have check valves and-pneumatically-actuated control valves positioned by hand regulators. "he-three lines are also pmvided with pressure transmitters f o r the recorders and the alarm system. Vent lines 582, 584, and 586 f r o m the transmitters contain floating diaphragm seals which would store any gas t h a t might escape a leaking transmitter. These lines vent t o l i n e 588, a I/k-in. OD tube, leading t o the radiation and 596~,and then t o l i n e 937 and the off-gas dism n i t o r s RIA 5% charge stack. Decay heat is r e m e d fromthe drained f u e l salt in FD-1 and FD-2 by bayonet-type, boiling-water cooling tubes.

The steam drum, o r dome, above

each drain tank sepamtes-the water from the steam-water mixture discharged from the tubes, a@ recycles-.the-mter t o the tubes. The saturated steam is transported by 3-in., sched-40 stainless s t e e l pipes, l i n e s 804 and 805, t o condensers, DfC-Lemcl XW-2, located i n the west tunnel area. The con&emers are cooled by-process water circulated through l i n e s 810 an8 8=, and 83.2 and 813. Contiensate .f3mby gravity from t h e condensers t o feedwater storage tanks-located beneath the condensers via 1-in. lines 878 an8 879. Water is recimnla.t;ed-fra *e feeawater tanks by gravity feed t o t h e steam drum through 1-b. sched-40 stainless s t e e l pipes, lines ~

806 ana 807. Valves LW-806 land LIC-807, f o r these valves are connected t o the steam drum but-are located i n the transmitter room. The maximum rate of feedwater flow i s about 2.1 gpm. When the decay heat generation

P t

226

i s low, intermittent operation of the-cooling system i s required. To reduce the cooling rate t o zerof t h e water flow i s shut off and the tubes allowed t o evaporate t o dryness. Steam fromthe X-10 plant i s condensed t o provide water f o r the heat removal system. Both the condensers and the feedwater tanks are vented t o the vapor condensing system through l i n e s 808, 888, and 889. These l i n e s join t o form 1-in. l i n e 338, which leads t o l i n e 980 connecting the vapor-condensing system t o the primary containment. The top of each steam drum i s vented t o i t s respective condenser through l i n e s 804 and 805. The l/2-in. sched-40 pipes, l i n e s 107, 108, and log, which dip t o the bottoms of the flush tank, FFJ!, and the drain tanks, FD-1 and FD-2, are used t o interchange s a l t between the tanks and the f u e l processing cell. Each of these l i n e s is provided with a freeze valve before they merge t o form l i n e ll0, a 1/2-in. sched-40 pipe leading t o the f u e l storage tank, FST. The freeze valves and the juncture with l i n e U O are shown on the f u e l processing flowsheet, Fig. 6.2 (ORNL Dwg. AA-A-40887) shown here f o r convenience. These freeze valves are equipped with the salt reservoirs at both ends of the flattened portion t o assure salt i n the valve at a l l times. The freeze valves am! provided with thermocouples i n an identical manner with the valves on l i n e s 104, 105, and 106, described above. The 1t o 15 cfm (std) of cooling gas needed f o r the valves i s supplied through l i n e s gll, 912, and 913, which branch from l i n e 920, previously mentioned.

kid e Ir

6.3 Drain Tanks No. 1and 2 6.3.1

Description Fuel drain tank asseniblies-No. 1and 2, FD-1 and FD-2, are alike except f o r the nozzle orientations (see general assenibly drawings ORNL Dwg. E-W-A-40455 and E-FF-A-40731); A complete assembly consists of the tank-with supporting-skirt, thinibles, and steam d m with attached bayonet-type cooling tubes, as i l l u s t r a t e d i n Fig. 2.6. The tank surpports are described i n Section 6.3.5 and the steam drum and other portions of the decay heat removal system i n Section 6.3.3, following.

228 The drain tanks a r e 50 in. i n diameter and about 86 in. high, not including the steam dome, and hold about 80.2 f t3 ) of salt contained i n

t h e primary circulating loop.

The t a r e weight of a drain tank, includinR

i s 7000 lb.

the steam drum, etc.,

The maximum weight i s about 17,000 lb.

3-27

Other dimensions of the tanks a r e given i n Table 6.1. The top head of each drain tank a c t s a s a tube sheet f o r 33 thinibles of 1-1/2-in.

sched-40 INOR-8 pipe, about 77-1/2 in. long, which extend

i n t o the tanlcs t o about t h e elevation of the lower head welds.

All but The re-

one of the thimbles project about ll i n . above the upper head. maining thimble i s f o r thermocouples.

The 32 thimbles are evenly spaced

on two c i r c l e s concentric with t h e centerline of each tank, 20 on the outer c i r c l e , and 12 on the inner one.

The thimbles serve a s recept-

a c l e s f o r the bayonet-type cooling tubes and have f l a r e d openings a t the upper end t o f a c i l i t a t e i n s e r t i o n of t h e bayonets.

It may be noted

t h a t two independent b a r r i e r s , t h e thimble wall and t h e bayonet tube

w a l l , separate t h e f u e l s a l t from the water. The annular gas space between t h e two walls i s open t o t h e c e l l atmosphere, which i s continuously monitored f o r the presence of f u e l s a l t , water, and t h e products of t h e i r reaction. The f u e l t r a n s f e r l i n e s 108 and 109 e n t e r the drain tanks through the

upper head flange and extend downward t o a cup a t t h e center of t h e lower head.

This cup, which i s fabricated of a 2-in,

INOR-8pipe cap welded

t o t h e outside of t h w lower head, makes I t possible t o remve e s s e n t i a l l y a l l t h e salt from t h e tank. Lines lo5 and 106, which are used t o exchange f u e l s a l t w i t h t h e e

primary circulating system, enter through t h e top head of each tank and

extend downward, with a bend a t the lower end, t o terminate approximately 2-5/8-in.

above the lower head, and near i t s center.

The lower end of

each of these pipes i s closed, and a segment of the pipe wall i s cut away a t the bottom end t o provide an opening which does not draw s a l t from the

This leaves a "heel" of about 1/2 ft' of s a l t below

bottom of the tank.

the i n l e t t o minimize t h e likelihood of transferring any s o l i d s from t h e bottom of the drain tank i n t o the f u e l circulating system. (

L L

. .

~~~

... .. ..

.... . . ...

. . . ...

229

Table 6.1.

Design Data f o r Drain Tanks No. 1 and 2

Fuel Drain Tanks (two) Construction-materid. Height (without coolant headers), in. Diameter, in. (OD) r'

IIVOR-8 86 50

Wall thickness. in. Vessel Mshed head

Volume a t l250-, f't3 T o t a l .(excluding coolant -tubes) Fuel (min., n o d fill conditions)

Gas blanket (max., n o m 1 fih conditions) Heel and runback (min.) Design temperature, "F

00.2 73.2 7.0 2.7 1300

Design pressure, psi Cooling method

Boiling water i n double w a l l thinibles

cooling rate (design), kw

100

Coolant thinibfes Nuniber Construction material Size, in. Concentric feed tube (IIBOR-8)

Steam riser (INOR-8)

IIVOR-8 1-112 an. sched-40 XI2 in.'OP by 0.042-in. 1 in. IPS sched-40

a t

230

The above-mentioned i n t e r i o r fuel-salt piping i s held i n position inside the tank by restraining brackets fabricated of 1/4-in.-diam

INOR-8 rod. A nozzle i s provided i n the top head of each tank f o r installation

of the level probes, ID-1 and ID-2. The probes are the single-point, conductivity type, and indicate whether the salt l e v e l i s above o r below points marking 5$ and 9096 of the salt volume. A 3-in. pipe nozzle a t the center of the head serves as an inspection port and can also be used f o r installation of a salt sampler, The closure f o r t h i s nozzle i s an eight-bolt blind flange with an integral ring-joint gasket provided with leak detection openings. A 1/2-in. nozzle on the top head serves as a common connection f o r helium cover-gas ventand preseurization l i n e s 572 and 573 on FD-1, asld f o r l i n e s 574 and 575 on FD-2. The l i n e s are provided with a large loop encircling the top of the tank, i n much the same manner as the drain lines, t o provide f l e x i b i l i t y . The nozzle, the short length of connected piping, and the disconnect flange are of INOR-8. (Beyond t h i s point the l i n e s are fabricated of stainless steel.) The four-bolt disconnect flange i s a 1-in. size, but i s d r i l l e d f o r 1/2-in. NPS, with a side outl e t t o permit installation i n a horizontal position and easy access t o the bolting from above, The INOR-8steam drum and salt-coolin@;bayonets are an integral unit. The 32 bayonets a r e f a b r i c a t e d of 1-in. sched-40 INOR-8 pipe, a s shown in Figs, 6.3 and 6.4. A 1/2=in. OD tube on the inside of each bayonet serves as the downcomer for the entering feedwater. The 1-in. bayonet size increases t o 1-1/2-*pipe size above the elevation of the thinible openings, and a 1-q2-in0 corrugated, flexible Inconel hose

is welded t o each,

(The corrugations are covered with stainless s t e e l The other end of each hose i s welded t o 1-1/2-in. nozzles

braiding.) a t corresponding positions on the bottom of the steam drums. The 1/2-in, downcomers have stripmuid Ibconel flexible hoses i n the same relative position. This flexible arrangement provides for the differences i n radial thermal expansion between the drain tank upper head and the steam drum.* The weight of the steam-and-water-filled bayonets is not imposed on the flexible hose couplings but is carried by a plate on which a collar %ee Part N, Ref

. 15,

Myers, J. C.,

e t al., Drain Tanks. c

A I

231

Fig. 6 . 3 . Fuel Drain Tank Steam Dome Bayonet Assembly. ! .7

232 UNCLASIFIED ORNL-LR-DWG 60838AI

BAWNET SUPPORT PI-ATE

-Fig. 6.4. Bayonet Cooling Thimble for Fuel Drain Tank.

233 kd

welded t o each bayonet tube rests. - This 1/4-inW 304 stainless s t e e l plate is suspended f r o m the steam d m by four l/k-in.-diam stainless s t e e l wire cables. The plate clears the tops of- the thinibles by 1/4-in. so t h a t none of the weight of the stem drum and attached bayonets i s carried by the drain tank i t s e l f (see Section 6.3.5, following). The 1-1/2-in. nozzles on the-bottom of the s t e m drums extend about 7 in. into the drums. The 1/2-in. downcomer tubes bend inside these

* 5

nozzles and e x i t through the nozzle wall. The elevation of these e x i t openings alternates In adjacent thimbles on both bayonet Circles, one-half being a t 1 in. above the steam d m lower head and the other half a t 5 in.

(see ORNL Dwg. D-FF-A-40465).

With t h i s arrangement, the water level i n

the drtnn-may be-adjusted to-take one-half of the cooling thimbles out of service and thus obtain b e t t e r control of the temperature of the s a l t stored i n the t@. The 48-in.-diam by 18-in.-high steam drum has an 8-in. pipe penet r a t i o n through it a t the center- (see Fig. 2.6 and ORNL Dwg. D-FF-A-40456) The central openings allow the 3-in. inspectton nozzle on the drain tank t o extend above the steam drum for-accessibility. Lifting eyes on the top of the steam allow #e drum and the attached bayonet tubes t o be raised and s e t aside fpr-xwdntenance on the drain tanks. The 3-in. steam outlet and t h e 1/2-in, water i n l e t connection nozzles on the steam drum are fabricated of IN OR-^ between the drum and the bolted disconnect couplings. Ttpe mating; flanges-an&tha-mmainder of' the piping in t h e heat removtil system ere 394 stainless-steel. me 3-in. steam piping contains a corrugated, bellow-type, -stahless ste+-lexpansion Joint i n a horizontal run lnsiae the drain tank ceU.---TPhe-1/2-in. water l i n e bas sufficient f l e x i b i l i t y without use of an expansion joint. Tbe condensers,and the feedwater tanks used i n the heat rem1 systems are described i n Section 6.3.3. -- - -

b T.

(td C

t c

The drain-tank wall temperatuse is monitored by 20 thermocouples. !PkO of these are located on the top head a t the f u e l system drain and f i l l line; four are located on the bottom head, two of &ich are a t the center; the remaining 14 are distributed over the cylindrical tank w a l l . Two of the thermocouples on the wall are at the tank charging line. The data logging system i s supplied with themcouple readings from the f u e l

* It

234 system fill line, the tank charging line, the tank wall near the midplane, and at the center of the bottom. One of the tank w a l l themcouples i s

i ")

connected t o a temperature recorder and the remaining lead t o a scanner which monitors and displays the values. The previously mentioned thermocouple bayonet assembly, which i s inserted i n t o a thimble i n the drain tank, carries f i v e pairs of thermocouples distributed over its length. One of the lower of these couples is connected t o the data logger and one, j u s t above midplane, has i t s output read on a temperature indicator.

6.3.2

&sip The drain tanks, thinibles, bayonet cooling tubes, steam drums, and

a l l attachments welded t o them, with the exception of the flexible hoses,

are fabricated of INOR-8 and generally i n accordance with Specification The flexible hoses w e r e fabricated of Inconel and meet MSR-62-3 the specifications of Section VI11 of the ASME Unfired Pressure Vessel Code 47 The drain tanks w i l l withstand an internal pressure of 65 psig and

1300°F i n accordance with the requirements of Section VI11 of the ASME Unfired Pressure Vessel code, f o r primary nuclear vessels.'' The allowable stress i n IEJOR-8 at 13OQoFwas taken t o be 3500 psi.16 The calculations f o r wall and-head thicknesses, etc., were based on standard relationships and are presented i n Part IV of Ref 18 and i n R e f 104. Basic design data are shown i n Table 6.1. Calculations covering-differential thermal expansion between the drain tanks and steam drums, and transient and o f f d e s i g n operating conditions, are also given i n - P a r t Dl of Ref. 18. The drain tank and cooling system was designed f o r a cooling rate of 100 kw. Heat transfer and hydraulic computations are given i n Part IV,

Ref. 18.

6.3.3

Decay Heat Removal system The heat generated by the decay of fission products i n the f u e l salt stored i n the drain tanks i s removed by boiling water i n bayonet tubes inserted i n thimbles which are immersed i n the s a l t . This arrangement provides double barrier protection between the salt and the water.

235 The saturated steam-water mixture f r o m the bayonets is discharged into a steam drum, where the water is separated an8 recycledto the bayonets. The steam i s condensed outside the d m l n tank c e l l and the condensate returned by gravity through flow-control valves t o the downcomers i n the bayonet cooling tubes. The r e l i a b i l i t y of the system is enhancedby t h i s simplicity of operation. The drain tanks, thhibles-bayonet t a e s , and steam drums, a l l located i n the drain tank cell, have been described i n Section 6.3.1 The condensers and fedwater tanks are located i n the west tunnel, an

i s not accessible when the reactor I s I n operation but can be area ai& entered a short time a f t e r shutdown. The two condensers are commercial s h e l l and tube units, about 8+/8 in. 2 dim by 7 ft 1 0 4 2 in. long, with about 38 ft of surface and a capacity of 300 kw. Other dimensions and data are given i n Table 6.2. The units meet the requirements of the ASME Unfired Pressure Vessel Code, Section VIII, f o r secondaly nuclear ~ e s s e l e . The ~ ~ shell-side design pressure i s 50 psig, although the steam w i l l condense i n the s h e l l a t essentially atmospheric pressure. The cooling water, o r tube-side, design pressure i s 150 psig. The shell, tubes, and baffles are a l l fabricated of 304 stainless steel. The two cylindrical feedwater tanks are 36 in. i n diameter and about 24 in. high, including the Al&B flanged and dished torispherical heads. 3 They are constructea of 304 s t a i n Each has a volume of about lO.5-ft-. l e s s steel, with a wall thickness of 3/16 in., i n accordance with the requirements of Section VI11 of the ASME Unfired Pressure Vessel Code, f o r secondary nuclear ves6els.4'- -Each tank i s supported by four legs, and the bottom of the tank is-about 12 Zn. above floor level. A 1-in. nozzle a t the center of the lower-head serves as both the condensate i n l e t and outlet, the tanks ~floatdng"on lines 806 and 807. Both top and bottom heads have 1/2-in; -nozzles f o r the level inalcator connections, the top nozzle also serving as a vent f o r the tank. A 2-in. flanged nozzle i s provided at the top of each tank a s an inspection port. As previously mentioned a feedwater control valve in each heat removal system, IXN 806 and LCV 807, control the gravity flow of condensate from the condensers and feedwater tahks t o the steam drums. These

236 Table 6.2

Design Data f o r Condensers in Drain Tank Heat Removal_Systems

4id t

1. Construction material Shell, tubes, baffles, and tube sheet 2.

3. 4. 5. 6.

7. I

8. 9. 10. ll.

12.

Dia. of s h e l l Overall length No. of units required Heat transfer rate, capacity Design pressure Shell side Tube side Test pressure Shell side Tube side Operating pressure, s h e l l side Design t e q e r a t u r e Heat transfer surface No. of tubes Tube size Tube spacing

75 PS%

225 psig 15 psia

267 F 38 f't2 19 "U" shaped 518 in. 0. D. 13/16 in. triangular pitdl

237 pneumatically operated valves were selected t o f a i l i n the open position, since overheating t h e drain tanks i s more serious than overcooling, part i c u l a r l y i n t h a t t h e l a t t e r could be l a r g e l y overcome by the e l e c t r i c heaters.

By controlling t h e water l e v e l i n the drums, t h e entrance

openings a t two l e v e l s i n the bayonet tube downcomers permit t h e cooling capacity t o be off, one-half off, or a l l i n operation, thus affording control of t h e s a l t temperature i n t h e drain tanks. The condenser s h e l l spaces and t h e feedwater tanks are vented t o the vapor-condensing system tanks, which are a t e s s e n t i a l l y atmospheric pressure.

The entering steam drives t h e a i r out.

When the steam supply

i s cut off, air w i l l be drawn i n as t h e remaining steam condenses. A l l t h e water i n t h e heat removal systems can be stored i n t h e feedwater tanks.

The water i n the steam drums can be evaporated, using t h e

drain tank heaters, and collected i n t h e feedwater tanks. Design calculations are given i n Part N of Ref. 18.

6.3.4

Drain Tank E l e c t r i c Heaters and I n s u l a t i o n The two drain tanks a r e heated by c y l i n d r i c a l "furnacesff surrounding

t h e tank w a l l s .

The tank tops, bottoms, and heater u n i t s a r e enclosed i n

canned i n s u l a t i o n u n i t s .

The heaters f o r drain tank FD-1 have a t o t a l

capacity of 46.9 kw and t h o s e ' f o r FD-2 a t o t a l capacity of 45.0 kw.

The

difference i n heater capacity i s due t o t h e arrangemen% of heaters r e -

quired for the different nozzle locations on the t w o tanks. "he tank wall heaters a r e arranged i n removable v e r t i c a l sections,

o r panels, each about 2 3/8 in. t h i c k (see ORNL Dwgs E-MM-B-51684 and

51685).

The heaters are arranged i n t o two groups, an upper and a lower,

each group being supplied w i t h e l e c t r i c power from a separate induction regulator (see heater schedule, ORNL Dwg ~-m-~-51651).There a r e two widths of panels, one covering about 35' t h e other about 1 5 ' .

of t h e tank circumference, and

On FD-1 t h e r e a r e s i x of t h e l a r g e panels, with a

capacity of 3680 watts (at 230 v > each, and one of t h e smaller panels

(1360 w a t t s at 230 v), i n t h e upper group of heaters. lar number i n the lower group.

There a r e a simi-

Drain tank FD-2 has f i v e of the larger

u n i t s and t h r e e of the smaller i n each of the upper and lower groups.

I li

238 The heaters i n each group are connected-in parallel t o the wyeconnected secondary of the power transformer. Unlike other heaters i n the MSRE, one terminal of each of the drain tank heaters i s grounded

through the grounded center tap of the transformer wye. Each of the large panels contains four heating elements consisting of curved ceramic plates i n w h i c h the nichrome heating wire i s embedded. he elements are mounted i n stainless s t e e l frames and enciosed i n 16-gwe 347 stainless s t e e l t o complete the panel assenibly. Each panel has a l i f t i n g hook and separate power and thermocouple disconnects (see ORNL Dwg. E-MM-B-51610) The outside of the heaters and the tank bottoms are insulated with two 2-in.-thick layers of expanded-silica (Carefiemp 1600OF see Section 5.6.6.3) insulation. The high temperature side of the sheet metal cms for the insulation i s fabricated of I l - g a g e 347 stainless steel. The low temperature, o r outside, surface of the cans i s 16-gage carbon steel. An insulated cover f i t s between the steam drum and the drain tank a t an elevation ,just below the bayonet-tube positioning plate. This location permits the primary system drain and f i l l lines t o be inside the heated furnace. The 4-1/2-in.-thick cover is fabricated more o r l e s s i n place and is an integral part of the steam dnrm and bayonet tube assembly. A < 6-in.-wide portion of the cover on the outer circumference consists of two 2-in.-thick layers of expanded s i l i c a insulation. The r e m h i n g inner portion i s insulated w i t h ceramic fibers (Fiberfrax see Section 5.6.6.3). !Ibis flexible type of insulation is used because it i s easier t o f i t around the large nuuber of bayonet cooling tubes. Tbe insulated cover i s canned in 16-gage 347 stainless s t e e l on both sides. All of the drain tank heaters are designed for use and none are connected as spares. The installed capacity of about 45 kw f o r each tank, however, i s greatly i n excess of the 20-kw measured heat loss from a drain tank a t 1200°F. The same t e s t s indicated that about 34 kw i s required t o heat the tanks from 50 t o l150°F at a rate of 6-7"~ per hour. 126

fw t

6.3.5

Supports f o r Drain Tanks Each of the two drain tanks i s supported by two columns resting on the drain tank c e l l floor (see ORNL Dwg. E-IT-D-41500). The! supports b

e s

239

LJ *

were designed f o r a load of 17,000 lbOe7 Each drain tank installation incorporates two pneumatic weigh c e l l s f o r estimating the inventory of s a l t i n the tanks. Each drain tank is provided with a support s k i r t welded t o the tank j u s t above the upper head circumferential weld. Twelve ty-pe 316 stainless steel hanger rods, 3/4 in. OD by 15 in. long, are fastened by clevisty-pe couplings t o t h i s s k i r t and suspend the tank f r o m x t support ring loctzted a t about the elevation of the bottom of the steam drum. This carbon s t e e l support ring is about 53 in. OD x 6-1/2 in. wide x 8 in. deep, b u i l t up of steel plates, and has two 22-3/4-in.-long arms extending from it on opposite sides. Each of these arms i s suspended by three hanger 3t. bolts, 1/2-in, OD by 38 in. long, fabriaated of carbon s t e e l f r o m a pneumatic weigh c e l l resting on top of a support column, Each of these two weigh c e l l s has a point suppork consisting of a bearing b a l l 3/4 in. i n diameter. The support columns are fabricated of 5-in, sched-40 carbon steel pipe, except f o r the top 24 in., which is 4-in. sched-40 pipe, and r e s t on the drain tank c e l l floor. The columns pass through holes i n the arms on the support ring with 1/4-in. clearance on a diameter, an mount sufficient t o allow proper-operation-of the weigh c e l l s while a t the same time t o prevent the tank assexibly from f a l l i n g off the two support points. The long hanger b o l t s and the point support arrangement reduces the horizontal leading on the weigh c e l l s t o a negligible mount. The steam dmrm and bayonet assembly also rests on the support ring mentioned above and is thus a part of the t o t a l loading indicated

by the weigh cells. To effect maintenance on a weigh c e l l o r prior t o removal of a drain tank of i t s cooling system, the weight of the drain tank assembly must be removed fromthe weigh cells. To accomplish this, the end of each support ring arm i s equipped with a jack b o l t which operates against a bracket on the supporting columns j u s t below the arm. A slight l i f t i n g of the armby t h i s b o l t will permit unthreading of the three hanger bolts on each weigh cell. It may be desirable t o remove the weight fromthe

W 4

A-193 Grade B7,

240

Lid jack b o l t s f o r example t o prevent sway%ng during removal o r replacement of t h e steam drum and bayonet assenibly. To pmvide for this a collar i s installed on each column j u s t below the arm onto which the weight of the assenBly can be lowered by backing off the jack bolts. On i n i t i a l installation, the bayonet tubes were lined up and guided into the thinible openings under shop conditions. Replacement of the

steam drum bayonet tube assenibly i n the radioactive drain tank c e l l environment requires use of a guide plate slipped over the lower end of the bayonets t o a l i g n them for-entry gnto the thinible openings. The thinibles have flared openings eo assist i n t h i s operation. Once inserted, the steam drum assembly i s lowered, w i t h the guide plate slipping up the bayonets, and the plate i s l e f t in place resting on the tops of the thinibles. Further description of maintenance procedures is given i n Part X.

6.4 Fuel Flush Tank B e flush-salt storage tank i s located i n the drain tank cell, Fig. 4.4 and Fig. 4.5, and i s used t o store the salt used t o cleanse the primary system prior t o charging with f u e l sa&*. The flush salt consists primarily of 66$ Li'F and 34s BeF4 (see Table 2.1 and Part IV). The flush-salt tank has the same dimensions a s the f u e l drain tanks (see Section 6.3, above) but i s two inches shorter i n overall height. The tank has a storage capacity of 82.2 ft3 however, as compared t o 80.2 f t3

i n the drain tanks because of the absence of cooling thimbles.

The materials of construction and the design criteria are the same as f o r the drain tanks. The design data are summarized i n Table 6.3. The design calculations are presented i n Part IV of Ref. 18. The flush salt tank i s supported i n the same manner as the drain tanks and i s heated by an identical e l e c t r i c furnace arrangement having a capacity of 8.8 kw. The thermal insulation i s arranged i n essentially the same fashion. The tank temperature i s monitored by 3.5 thermocottples. Two are on the top head and four are on the bottom head w i t h two of the latter at the center. The other nine themcouples are distributed over the tank w a l l surfaces, w i t h two of these a t the charging line. The 1-in. drain l i n e 104 encircles the flush tank, FFT, a t the top

. c

24L

Table 6.3 Design Data for Fuel System Flush Salt Tails Construction materi&l

INOR-8

Height, in.

-84

Diameter, in. (O.D.) Wall thickness; in.Vessel Dished head Volume, ft3 ( 1250°F)

Total Flush salt (normal f i l l conaltions) Gas b-et * (vorplal fill conditions)

Design temperature, O F Besign presswe, psi cooling method.

1/2

3/4

m II

242

t o provide the f l e x i b i l i t y needed f o r weigh c e l l operation, in an arrangement identical t o that on the drain tanks. This l i n e has a freeze valve, FV-104, and the salt transfer l i n e t o the fuel-processing oell also has

. ’*

a freeze valve, FV-107 (see flowsheets, F i g . 6.1-4RML Dwg. D-AA-A40882, and M g . 6.2--Om-m.b-AA-A-40887). !RE flush salt tank is vented t o the fuel salt circulating pump bowl, via l i n e s 576 and 546, and t o the off-gas system, through l i n e s 576 and 577, each of which has pne-tically operated control valves act=-ted by hand-operated regulators Zocated on the control panels. The two-point l e v e l indication system is identical t o t h a t used on the fuel drain tanks.

6.5

Salt-Transfer Pipe Line Supports

Drain l i n e 103-1s supported by nine constant-load Bergen supports, as shown i n Table 6.4. Three of these supports are located i n the reactor c e l l and six are in the drain-tank ceU. Pipe hangers (both numbered S-5) support each end of a beam passing through the opening between the reactor and drain tank c e l l s t o support that portion of l i n e 103. Line 103 is anchored at the hea%Ing lug connection near the Juuction w i t h line 104 I n the drain tank cell. Line 104, 105, ZO6, and-ll0 each have one constant-load type pipe support. The 1/2-in. pip-, l i n e s 107, 108, and 109 are mounted i n simple fixed pipe hangers. c

Table 6.4

S a l t Transfer Pipe Line Supportsa

Line Number

s-3

s-4 s-ge

s-ge S-6 s-7

S-8 S-9

s-10 Anchor S-11

S-12 s-13 TL

Location

Bergen Numberb and Type

lbs

Maximum Hanger Movement, in.

Maximum Calculated Pipe Movementdon Heating, in.

- 1-118

About 1 ft outside thermal shield Between S-3 and. S-5 About 5 f t from reactor cell wall About 6 in. from south w a l l drain t a n k c e l l Middle of south w a l l of drain tank c e l l Southwest corner of drain tank c e l l Middle of west wall of drain tank c e l l A t 90" bend on west wall of drain tank c e l l

CSH-1 D - 1

100

CSH-1 D - 1

100

CSH-4 D - 1

235

2 1

-112

CSE-4 D - 1

235

2 1

-112

CSH-1 D - 1

121

-114

CSH-1 D - 1

3-27

-5132

CSH-1 D-1

115

2 1

-1116

About 7 f t from west wall of' drain tank c e l l About 3 f t 4 i n . from east w a l l drain tank c e l l South O f FV-104

CSH-1 D - 1

121

negl

5 1

-114

North of FV-106 South of FV-lOg Near north w a l l of drain tank c e l l

CSH-4 D - 1 CSH-4 D - 1 CSH-1 D-1

365 240 260

2 1

-114

f l

-114

100

2 1

-112

CSH-1 D-1

CSH-5 D-1

a See ORNL DWR Constant-load type supports Bergen Pipe Support Corporation (New York, N.Y.) c Preset load i s expected weight of pipe and contents.

Preset LoadC

Positive values a r e up; negative values down. S-5 hangers support each end of a beam which supports l i n e lo3 between reactor and drain tank c e l l s .

244

SAMPLER-ENRICRER SYSTEM

"he MSlU includes provisions f o r dipping 10-g samples of salt

f r o m both the f u e l and coolant-salt pump bowls while the r e a c t o r i s i n Shielded c a r r i e r s are provided f o r transporting the samples

operation.

t o the a n a l y t i c a l laboratory.

Chemical analyses of the samples provide

frequent observations of the behavior of the salts and, i n the case of the f u e l salt, of the uranium inventory i n the system. The sample-taking system may a l s o be used during r e a c t o r operation t o add up t o 150 g of enriching salt (72 mole $ LiF

- 28 mole $ UF4) per

sample capsule, t o compensate f o r the burnup of f i s s i l e material.

Should

it become necessary, the same system may a l s o be used t o add a nuclear

poison (Li F-BeF2) t o the f u e l - s a l t c i r c u l a t i n g loop.

(To make gross

changes i n t h e f u e l - s a l t composition, it i s necessary t h a t it a l l be drained from the c i r c u l a t i n g system and t r a n s f e r r e d t o the f u e l - s a l t processing c e l l . ) The sampler-enricher systems f o r t h e f u e l - s a l t and coolant salt

systems operate on the same principle.

The primary differences between

t h e two stem from the f a c t t h a t the r a d i o a c t i v i t y l e v e l i n t h e coolant

salt i s much less than i n the f u e l salt, t h a t t h e containment of f i s s i o n product gases i s not a problem, and that the equipment can be approached

a s h o r t time a f t e r r e a c t o r shutdown f o r adjustment and maintenance.

The

f'uel-system sampler-enricher i s described i n Sections 7.1 through 7.9. The equipment f o r the coolant-salt system i s b r i e f l y covered i n Section

7.10. 7.1 Brief Description of Operation The sampler-enricher system c o n s i s t s of a 1-1/2-in. -dim t r a n s f e r tube connecting the t o p of t h e pump bowl t o a two-chambered, shielded

transfer box on the operating f l o o r l e v e l . A small copper capsule, fastened t o t h e small w i r e cable by a s p e c i a l l a t c h , i s lowered through t h e tube i n t o a cage beneath the surface of the salt i n the fuel-pump bowl. The capsule, with i t s 4-cc sample (10 g of salt), i s then pulled up through the tube, through two gate valves, and i n t o t h e shielded

245

Ld I

leaktight transfer box. Using a simple manipulator and a periscope, the sample capsule i s unlatched from the cable and transferred t o a transport container about i03/8-i~.in dianeter by 18-in. long. After the transfer box has been purged, a removal t o o l i s inserted and the transport container i s pulled up into a lead-shielded transport cask. !&is cask i s then placed in a sealed container and taken t o the anal y t i c a l chemistry f a c i l i t i e s in the X-10 Area of ORNL. !two o r more barriers are provided at all times t o guard against escape of radioactive gases or particulates. E i g h t inches of lead, o r equivalent, shield the operator from radioactivity. A system of interlocks i n the sampler-enricher system prevents accidental opening of valves, etc. A procedure in reverse of that described above is used f o r adding enriched salt t o the system, A longer copper capsule i s used, holding 30 cc. This capsule i s lowered into the pump bowl where the enriched material quickly melts and drains through openings in the capsule as it is raised from the bowl, Poison material may be added in essentially the sane manner.

a f

7.2

Design Criteria

The unique features of the sampler-enricher system--primarily the f a c t that the sample-transfer tube passes through both the primary and secondary containment barriers in the MSRE--led t o adoption of relatively summythese stringent criteria f o r the design of the system. 128

are:

The samples taken must be representative of the salt circulating in t h e system. It may also be desirable at times t o take separate s q l e s in which the material floating on the surface of the salt in the pump b&l predominates. Each sample must be easily removable from the cap-

. V i

sule, and all of it recovereU for chemical analysis, Approximately 4 cc (10 g) of salt must be isolated per sample, and the system must be capable of taking three samples per 24 h r f o r one year o r more. prenuclear runs, etc., the sampling may be more often,

During

246

hi+ 7.2.2

Enriching

About 30 cc (150 g) of enriching salt (72 mole $ Li6 28 mole $ W4) w i l l be added per capsule. Each 30-cc addition w i l l contain 90 g of 235U and/or thorium. The capsule must drain coqiletely, and recovery of the empty capsule must be assured. The enriching salt must enter the circulating f i e 1 stream as a liquid, not as a solid. 7.2.3

Poisoning s

The system must be capable of adding a nuclear poison t o the fuelsalt-pump bowl at a l l times, including outages of the e l e c t r i c a l power

6UPPly. 7.2.4

Addition of Contaminants

Helium gas introduced into the salt loops during sampling o r enriching operations must be of reactor grade. Portions of the system i n contact with the salt must be fabricated of ma-8 o r other materials that will not add contaminants t o the system. A d r y i n e r t atmosphere must be maintained around the sample at all times, including transport t o the analytical laboratory. (The capsule may be f i r e d i n a hydrogen atmosphere prior t o use t o remove the oxide film.) 4

7.2.5

Containment

Fission-product gases entering the sampling compartment must be purgedto the off-gas system prior t o removal of a sample. The sample must be sealed in a shielded container during transport. Portions of the sampler system which could be contamineted by particles of salt

must be sealed from exposure t o the atmosphere. Double c o n t w n t must be provided in such a manner that breaching of one barrier w i l l not result in the release of radioactivity t o the environment. AU. mechanical seals and valves in the primary areas must be buffered w i t h helium gas t o a pressure higher than t h a t in the reactor system, and leak-detection equipent must be provided. Any portion of the systemnot structurally strong, such as the flexible bellows, must be buffered with gas under a pressure l e s s than that i n the primary

247

system, and the buffered space must be vented t o the containment air system. Exhaust hoods must be provided i n the operating floor areas where the sampler-enricher equipment i s located. (For convenience, the containment weas in the sampler-enricher system were classified as follows: Portions of the primary containment were designated 1-a, 1-b, etc. Areas of secondary containment, such as the i n t e r i o r parts of the valve box, were designated 2-a, 2-b, etc. The outer compartment of the transfer box, also a secondary containment area during certain phases of the operating procedure, i s designated 3-a, etc. See Fig. 7.3.) A l l portions of the primary and secondary containment areas must be helium leak checked and the leak r a t e must be less than 1 x s t d cc/sec.

7.2.6

Stresses

The sampler-enricher equipment must be designed f o r a pressure of at least 50 psig i n primary containment areas and 40 psig i n secondary containment regions. Design temperatures range from EOO°F in the pump bowl t o about 100°F at the transfer box. (The normal operating pressure i s about 5 psig.) The calculated stresses i n stainless s t e e l must not exceed those allowed i n the ASME Unfired Pressure Vessel Code, Section V I I I , 4 7 and those i n INOR-8 must conform t o the allowable stresses shown i n Table 2.2 and ASME Boiler and Pressure Vessel Code Case 1315.52 The primary containment must comply with ASME Code Case E 7 3 N-750 and secondary containment with Code Case E72 N-5. 49

7.3 Description of Equipment 7.3.1

Capsules

Two types of copper capsules are used, one f o r sampling a d one f o r adding enriched o r poison material. 7.3.1.1 Sampl i n g Capsule. A s shown i n Fig. 7.1, the sampling P

LiJ J

capsule i s fabricated from a 3/4-in.-OD copper rod, drilled t o 5/8-in. ID, w i t h a rounded bottom. The solid copper top cap i s also rounded t o minimize the likelihood of becoming stuck i n the transfer tube o r

z W

249

-W J

valves. The cap i s pinned t o the capsule w i t h a short length of 1/8-in.OD copper tubing. Two holes through the cap permit the l/32-inO-OD twisted Inconel wire latch cable t o pass in and out t o provide a 7-in.long loop connecting the capsule t o the latehkey, t o be described below. The overall length of the capsule, w i t h end cap, i s about 1-13/16 in. Holes, 180' apart, in the side of the capsule, about 0.88 in. above the bottom, and roughly e l l i p t i c a l in shape, 1/4 by 3/8 in., w i t h the major axis at right Wgles t o the axis of the capsule, permit the salt t o enter the sampler af%er immersion in the salt in the bowl. The capsule v o l m below the level of the holes i s about 4 CC. A new capsule must be used f o r each sample. 7.3.1.2 Ehrichina Capsule. This capsule i s also shown in Fig. 7.1. It is fabricated of 3/4-in.-OD by 0.035-in.-wall-thickness copper tubing. The bottom i s spun shut on a radius of 3/8 in. The top i s closed w i t h a solid copger plug similar t o that used on the saslpling capsule but w i t h two 1/8-in.-OD copper tubes passing longitudinally through it. The molten enriched material (or poison) i s added t o the capsule through one of these tubes, which extends about 1/4 in. on the inside, and the displaced i n e r t gas i s vented through the other. After filling, the 1 / 8 - h OD tubes are cut off short and sealed. A hole i s d r i l l e d through the cap at a right angle t o the centerline for the 1/32-in.-o~a c o n e l wires Nine 0.191-in.-diam holes are then d r i l l e d used t o attach the latchke in the side of t h e capsule 120' apart and at 1-1/4 in., 2-1/2 in., and at 3-314 in. from the bott A tenth hole, 0.221 in. in diameter, is drillei in the bottom. Th about 6-318 in, it holds (go g 235~j. on insertion from the capsule as it is

rall length of the salt-addition tube i s i m t e l y 30 cc, o r about 150 g of salt

pun@ bowl the salt melts and d r a i n s ed out. A new capsule i s required for

each salt addition.

7.3.2

Capsule Iatch and Latchkey

end of the cable which ra,i.ses and lowers the capsule t o permit easy engagement and disengageknt of the capsule from the cable. This latch does not come into contact w i t h the salt. A latch I s provided at

250

7.3.2.1

Latchkey.

The l/32-inO-diamInconel wire attached t o

the top of each capsule, see above, i s f i t t e d w i t h a brass (or bronze) latchkey about 3/16 in. OD by 1-5/8 in. long, overall. The key has an enlarged section at the upper end, 5/16 in. OD by about 3/8 in. long, t o form a shoulder on the key which engages a notch i n the latch, as sham i n Fig. 7.2. The key i s disengaged from the notch by grasping the latch wire w i t h the remote manipulator fingers and l i f t i n g it slightly a s it i s pulled forward and upwards. A new latchkey is required for each sanrple taken. 7.3.2.2 La%&. As shown in Fig. 7.2, the stainless s t e e l latch

at the end of the cable i s 1-3/8 in. diam by about 2-1/2 in. long, and i s tapered at the lower end t o help guide it through the valves in the transfer tube, etc. A s l o t is provided i n the tapered end for insertion and support of the latchkey, the shoulder on the key r e s t i n g on the edges of the slot. "he upper end of the latch i s beveled t o When the latch i s in the full raised position, this beveled .'53 surface bears against a corresponding surface on the upper latch stop in the capsule removal charnber, causing the latch t o rotate on the cable t o the desired position x i t h the s l o t opening facing the access port. The upper latch stop i s described subsequently i n Section

7.3.7.10 7.3.3

Cable The cable used t o lower and raise the capsules through the trans-

Catalog Mo. 19553, oon8-in.-di~ by 25-ft-long 321 stainless s t e e l cable. It i s coated w i t h a high-temperature lubricant supplied by Teleflex, Inc. The cable can operate under a 35-1b tension load without being datuaged. fer tube i s a Teleflex, Inc. (North Wales, Pa.),

7.3.4

0 4

pump Bowl Equipment

7.3.4.1

Capsule Guide Cage. A guide cage i s provided inside the pump bowl t o confine the capsule t o i t s proper position i n the pool of

salt. As sham on OREL drawing F-RD-~~U-G, the cage i s fabricated from five 1/4-in.-diam by 8-1/4-in.-long I ~ ~ T Orods R - ~ attached t o a 1-1/8-in.-dit~11ring at the bottom. f

251

Unclassified

ORNL DWG 64-8822

2-11/16 REF I

1’ C

LATCH

/”’

CAPSULE K E Y

F i g . 7.2. Sampling Capsule Cable Latch.

252

7.3.4.2

Larer Lstch Stop.

A stop i s provided in the connection

between the t r a n s f e r tube and the capsule guide cage t o prevent t h e

bid t

l a t c h from entering the cage and coming i n t o contact w i t h t h e salt. The stop consists of a r e s t r i c t i o n tapering from 1-5/8 in. ID at the top t o 1-1/16 in. I D at t h e bottom.

The l a t c h stop a l s o serves t o

support the top ends of the rods f o r the guide cage.

7.3.4.3

Baffle.

A baffle p l a t e surrounds the capsule guide cage

t o shield it from excessive salt v e l o c i t i e s and, more importantly, t o

retard the aerosol of salt i n the vapor space i n t h e pump bowl from entering t h e t r a n s f e r tube.

This b a f f l e i s a, spiral-shaped INOR-8

plate, 1/8 in. thick by 8 in. high, curved t o about 3 in. o v e r a l l diam ter

7.3.5

t #

Transfer Tube A 1-1/2-in.

sched-40 pipe connects the t o p of t h e f u e l pump bowl

t o t h e bottom of the maintenance valve i n t h e sampler-enricher valve box located a t the operating f l o o r l e v e l (852-ft elev).

(See Fig.

The pipe, o r t r a n s f e r tube, i s about 14 ft long, with two 35-1/2'

4.3.) by

l5-in. radius bends a t t h e top and bottom, w i t h t h e c e n t r a l straight portion inclined at an angle of 5ko3Ot with the horizontal.

This i s

s u f f i c i e n t slope f o r the capsule t o drop i n t o t h e pump bowl by g r a v i t y alone (see Fig.

7 -3).

The t r a n s f e r tube i s fabricated of

IN OR-^ from the pump bowl t o

the expansion j o i n t section, described below.

The expansion j o i n t and

t h e upper portions of t h e t r a n s f e r tube are 304 s t a i n l e s s s t e e l .

7.3.5.1

Expansion J o i n t .

The t r a n s f e r tube includes an expansion

j o i n t at about t h e mid point t o provide the f l e x i b i l i t y needed t o absorb the movement of the pump bowl (see Section 5.4.5) fixed sampler-enricher s t a t i o n .

r e l a t i v e t o the

The expansion j o i n t section, o r spool

piece, i s about 40-1/2 in. long (see ORNL drawing D-BB-C-41337).

The

upper portion of t h e spool piece i s a s l i d i n g f i t i n t o t h e lower portion,

with a clearance of 0.003 t o 0.007 in. No. 6 S t e l l i t e surfaces.

Points of contact have ground

A 321 stainless steel bellows,

3.31 in. OD x

2.65 in. I D x 7 in. long, with a 2-ply w a l l , each 0.005 in. thick, and w i t h 32 convolutions, i s welded t o t h e upper and lower portions of the

253

Unclassified

ORNL IlwG 63-5848 m

,REMOVAL VALVE AND SHAFT SEAL

PERISCOPE CAPSULE DRIVE UNIT

LIGHT CASTLE JOINT (SHIELDED WITH DEPLETED URANIUM)

t I

ACCESS PORT L

AREA I C PRIMARY CONTAINMENT SAMPLE CAPSULE

TRANSf~ O R T rAlNER OPERATIONAL AND MAINTENANCE VALVES

m-v/A-

lr / /

LEAD SHIELDING

TRANSFER TUBE (PRIIMARY CONTAINMENT)

Figure 7.3.

Schematic Representation h e l - S a l t Sermpler-Enricher Dry Box

254 spool piece t o provide a l e a k t i g h t j o i n t .

The bellows w a s manufactured A

by the Fairchild Instrument and Camera Company ( E l Cajon, Calif.).

permanently attached jack, operated by a system of bevel gears and r o l l e r chains motivated by a remotely operated t o o l from above, permits compression of the expansion j o i n t f o r i n s e r t i o n between the flanges

a t t h e connection at each end.

(See ORNL drawing D-BB-C-41365.)

A po-

s i t i o n i n g j i g f o r t h e spool piece provides proper alignment of the flanges during r e i n s t a l l a t i o n . The flanges f o r t h e spool piece are, as are the other flanges i n the transfer tube assembly, 4-1/4 in. OD, i n t e g r a l O-ring, le&-detected

. t

units, with the mating faces held together by spring clamps which can be t

remotely removed by special tooling operated through the portable shield. 7.3.5.2

Sleeve.

The upper portion of the t r a n s f e r tube passes

through a sleeve as it crosses the annular space between the inner and outer reactor containment v e s s e l walls.

This 6-in.

sched-40 pipe i s

about 5-l/2 ft long, overall, and i s provided with a bellows-type expansion j o i n t at t h e mid point t o compensate f o r r e l a t i v e movement between the w a l l s of the two vessels (see ORNL drawing D-KK-D-40374).

Iead shielding f i l l s the annular space between the sleeve and the transf e r tube f o r a distance of 20 in.

7.3.5.3

Upper Terminus.

me upper end of the t r a n s f e r tube passes 5

through a box s e t i n t o the concrete a t t h e operating f l o o r level. box, fabricated of a 5-in.

The

section of 14-in. sched-10 pipe, i s closed

a t the top by a 2l-in.-diam by l-1/2-inO-thick flange bolted t o a corresponding flange on the top of t h e box with a double O-ring gasket, which can be leak detected. through, the flange.

The t r a n s f e r tube i s welded to, and extends

The 1-1/2-in.

pipe terminates inside t h e valve box,

described below, about 7-5/8 in. above the operating f l o o r elevation of 852 f t i n a b-l./k-in.-OD

i n t e g r a l O-ring flange having a spring-clamp

closure

7.3-6

~ pr aet i o n a l and Maintenance Valve Box

Two mechanically similar gate valves are located one above t h e other in a sealed valve box at t h e upper end of the t r a n s f e r tube assembly. The upper--or operational--valve i s used during normal operation of the

255

sampler-enricher system. The lower--or maintenance-valve i s normally open and I s closed only during maintenance on the upper portion of the sampler-enricher equipment, o r in case of failure of the operational valve t o seal properly, 7.3.6.1 Valve Box. The valves are located in a box about 15 in, x 19 in. x 38 in. high. The l 5 - b . by 38-in. sides face north and south, and the 19-in, by 38-in. sides face east and west. The southern side of the box has a cover plate bolted t o the box by 1/2-in. studs on about 4-b. centers, and a neoprene O-ring gasket w i t h metal-to-metal seats. The upper portion of t h i s cover has an opening, which, in turn, is closed by another cover plate with a neoprene O-ring gasket and bolted down by the same 1/2-in. studs, the studs being longer at the top of the box t o accommodate the two thicknesses of cover plates. The valve body i s welded t o the transfer tube and therefore the major portion of the weight of the valves and flanges i s carried by the flange welded t o the transfer tube at the operating floor level, The valve operating stems pass through the box cover plate i n belJnws-sealed joints. These joints seal the opening and a l s o allow some l a t e r a l movement of the valve f o r alignment. The two seals, or joints, are welUed t o the box cover plates, the lower one t o the large plate and the upper one t o the smaller, outside cover plate. Vertical alignment of the valves and flanges i s achieved by slotted holes i n the cover plates, permitting vertical shif’thg of each cover plate (about

1/4 in.) relative t o the flanges and t o each other. S i x 1-5/8-in.-diam tapped holes ase provided in the 19 by 38-h. west face of the box, each opposite an operator f o r the spring clamps on the three valve flanges. The holes are normally close& stainless s t e e l nuts, about 6 fn. long, which extend through the lead shielding on the outside of the box. The nuts are provided w i t h neoprene O-ring gaskets The valve box i s fabricated of 304 stainless steel. Tvo stiffeners of 1/2-in.-thick by 3-in.-wide plate are equally spaced vertically on the three sides of the box. The box was designed for a pressure of 40 psig at 100°F, although the normal operating pressure i s atmospheric. The box was hydraulically tested t o 54 psig or pneumaticaUy tested at

le6 psig.

It satisfactorily passed a helium leak check, w i t h a maximum leakage of 1x loo8 std cc/sec (see Section 7.2.6).

7.3.6.2

Valves. m e operational and maintenance valves are 1-1/2-in., 150-lb stainless s t e e l body, "Belloseal" gate valves manufactured by The W i l l i a m Ppwell Company (Cincinnati). The valves axe the double-sealing type, w i t h No. 6 Stellite-to-Stellite m e t a l seats. A helium pressure of 40 psig is maintained between the two seats when the valve is closed. The nonnal leak r a t e through both seats i s less than 1 std cc of helium per minute. The valve stems were modified by cutting and inserting about 6 in. of extra length so that a second stainless s t e e l bellows could be added to the stem seals. !Fhe valves a,re operated by "Idmitorque," SMA-OOO, control motors located outside the valve box. The motors are f o r 220-v, 3-phase operation and have an output torque of 2 ft-lb, w h i c h is geared t o produce 50 f t - l b at a stem speed of 6 in./min. -On closing, the torque-limiting feature cuts off the drive when the valve is fully seated, The interlocks i n the sampler-enricher e l e c t r i c a l system prevent operation of either valve motor while the capsule is i n the transfer tube. T&e motors draw power from the 25-kv motor-generator s e t which can be supplied with auxiliary battery parer in event of failure of the normal supply. In addition, the valve stem drive can be shifted t o manual operation f o r emergency closing of the valves.

7.3.7

Transfer Box

A-

* c

As a sample capsule is withdrawn through the transfer tube, it

passes upward throu& the maintenance and operation valves in the valve box and then into a capsule access chamber located i n the transfer box. As shown i n Figs. 7.3 and 7.4, this box i s located j u s t above the valve compartment. In addition t o the access chamber, in which the smple capsule is disengaged f r o m the l i f i i n g cable, the transfer box also contains the cable drive box, the manipulator, and the valve port f o r introducing the capsule transport container. The interior of the transf e r box, sometimes referred t o as the outer compartment, i s a region of secondary containment when the operational and maintenance valves are

257

Fig. 7.4. Capsule Access Chamber.

258

open. The capsule access chamber, or inner compartment (area 1-c i n Fig. 7.3), i s a primary containmnt region at this time. 7.3.7.1 Capsule Access Charober. The l-l/2-in.-diam upper end of the transfer tube assembly i s welded t o the bottom of a bellows, which, i n turn, has the top welded t o the bottom of the capsule access chamber (see Fig. 7.4). lplis arrangement accommodates relative movement and minor misalignment. The bellows i s 2-ply 304 stainless steel, w i t h each w a l l 0.004 in. thick. It is 2.406 in. OD x 1.562 in. I D x 3 in. long, has eight convolutions, and w a s tested at 75 psig. The manufacturer w a s Fairchild Instrument and Camera Company (El CaJon, Calif .). The bellows described above is housed i n a guide about 5 in. diam by 5-3/4 in. long, welded t o the bottom of the capsule access chamber. The outside of the guide i s provided w i t h two neoprene O-ring gaskets and f i t s into a short cylinder in the top of the valve box. When the flanged joint above the operational valve i s sepasated, t h i s arrangement permits the capsule access chamber and cable drive unit t o be w i t h drawn f o r maintenance through the top of the transfer box, as w i l l be described subsequent-. The 304 stainless s t e e l capsule access chamber has a s q m e cross section, about 4-1/2 in. on outside dimensions, i s about 10-3/8-in. high, and has w a l l s about 1/2-in. thick. A 2-3/4-in. by 8-in.-high opening and a door are provided on the south face. The door swings on hinges which are spring loaded t o hold the door in the open position. As shown i n Fig. 7.4, the door i s closed and clamped shut by three pneumatic cylinders on each side, operated by 75 psig helium, which are connected through pinned linkages i n a toggle action t o lock the door shut after the gas pressure has been released. The door i s opened by applying helium pressure t o the reverse side of the piston. These same links swing the clamps out of the way when released t o allow the door t o swing open. The clamgs are not attached t o the door but have Stellited rounded noses which bear against S t e l l i t e pads on the door.

The clamps, each of which

can exert a force of 300 l b on the door, are Knu-Vise Clamps, Catalog manufactured by the Lapeer Manufacturing Company (Detroit). Two Buna-N gaskets are provided on the door opening, and the space between the gaskets i s buffered with helium when the door i s closed.

Nundber AOM-200,

G i C

c 'c

259 A three-way valve i n the helium supply t o the pneumatic cylinders vents

the spent heliwnto the containment ventilation system. When the capsule is hoisted t o the fully raised position, the beveled surface of the upper portion of the capsule latch contacts a similarly beveled surface on a stop mounted i n the top of the capsule access chamber. As mentioned in Section 7.3.2.2, and sham i n Fig. 7.2, t h i s arrangement causes the latch t o rotate on the cable so that the notch faces the door opening. 7.3.7.2 Capsule Drive Unit and Box. The electric-motor-driven r e e l which raises and lowers the capsule cable i s located i n a drive unit box j u s t above the capsule access chamber. The interior of the box communicates with the chamber and i s thus also part of the primary containment. The box i s about 8-3/8 in, x 14-1/8 in. x 11 in. high and is fabricated of 1/2-ine-thick 304 stainless s t e e l plate (see ORNL drawing 10301 R-157-E) The box has a 1-1/2-in. -dim hole at the bottom through which the cable passes into the capsule access chamber. The box is designed for, and tested at, the same pressures as the access chamber. The transfer box has an 0-ring-gasketed cover bolted i n place j u s t above the drive unit box. After the flange above the operational valve i s separated, the l i f t i n g eyes in the top of the transfer box may be used t o gull the drive unit box and the attached capsule access chamber assembly upwards through the opening for maintenance or replacement. The capsule cable drive unit i s a Teleflex, Inc. (North Wales, Pa.), Catalog No. 19553, drive w i t h a storage r e e l holding 25 ft of cable. The cable is positively paid out and returned by a non-slip gear-driven wheel capable of exerting 35 l b of force on the cable in tension and 20 l b i n compression. (It is t o be noted, however, that the normet1 loading is but a small fraction of these values and t h a t the capsule drops damwasd to the p u p bowl solely by gravity.) As the cable moves upward through the drive wheel, it winds onto a storage r e e l which is spring-loaded t o maintaizl LL tension on the cable between the r e e l and the drive wheel, The drive unit motor is a ll5-v, single-phase, reversible, Jordan (Milwaukee) "Shaftrol" unit, Model SM-ll-W-3, 1/2 FXS, exerting 28 in.-lb

260

It i s provided with a b u i l t - i n e l e c t r i c brake. One revolution of t h e motor r e e l s i n about 8 i n . of cable. A threaded shaft, gear-driven from the motor, moves a nut along it t o contact l i m i t switch arms. An upper l i m i t , lower l i m i t , and two i n t e r mediate points a r e provided. The upper and lower l i m i t switches c u t o f f torque at 3-l/2 r p m output speed.

the cable drive motor while the intermediate positions a r e p a r t of the interlock system.

T!wo gear-driven synchro motors are incorporated i n t o

the drive unit t o send signals t o the "coarse" and "fine" p o s i t i o n i n d i c a t o r s on the operating panel.

These show t h e capsule p o s i t i o n t o within

1/8 in. of the a c t u a l point. 7.3.7.3 Transfer Box Lrtyout and Construction.

The box t h a t houses

the capsule access chamber and the drive u n i t i s a sealed L-shaped c m t a i n e r , w i t h the v e r t i c a l l e g about 15 in. by 20 in. and 24 in. high, and the horizontal l e g about 15 x 15 x 36 in. long (see Fig., 7.3).

i s fabricated of 1/2-in.-thick bars 1/2 in.-thick by 3-in.-wide

the 2bin.-long

sides.

304 st-less

s t e e l plate.

Reinforcing

are welded along t h e center l i n e s on

The design pressure i s 40 p s i g at 1OO0F, the

normal operating pressure being atmospheric. The box w a s hydraulically t e s t e d a t 54 p s i g o r pneumatically at 46 psig. The helium leak r a t e The was less than 1x s t d cc/sec (see ORNL drawing 10301-R-150-E). box, a s secondary containment, complies w i t h the ASME Code Case E 7 2 N-5. 49 The capsule access chamber i s located in the north end of t h e box, i n the v e r t i c a l leg, w i t h the d r i v e u n i t mounted above it.

The south

end of the h o r i z o n t a l l e g i s f i t t e d with a manipuhtor and a quartz viewing port.

The upper portion of the horizontal l e g i s provided with

another quartz p o r t f o r the illumination system and with a valve p o r t f o r i n s e r t i o n and removal of the sample-capsule-transport container. These devices a r e described separately i n the sections t h a t follow.

7.3.7.4

Manipulator.

A shielded manipulator extends through the

w a l l of the transfer box. It is used t o remove the capsule latchkey from the latch and t o l i f t the sample capsule from the access chamber t o the capsule-transport container, e t c .

As indicated i n Fig.

manipulator hand has two fingers of the forceps type.

7.3, the

These are actuated

by a push-pull rod extending through t h e arm t o the handle, located outside the t r a n s f e r box.

A grip-type lever, which has a r a t c h e t and pin,

263L o r trigger, arrangement t o lock it in any position, imparts &e p h p u l l motion t o the rod. The hand can be rotated about 180' by turning the asm. %he insides of t h e fingers are padded w i t h neoprene about 1/32 in. thick. The arm passes through the box w a l l i n a Castle-type joint. The side-to-side motion of the a r m is provided by a vertically mounted 6-in.-diam by 8-ino-hj-a depleted uranium cylinder that is mounted on b a l l bearings a t the top and bottom. This cylinder turns, w i t h a clearance of about 1/64 in., in a depleted uranium housing f i t t e d into the llC-in.-diam extension of the transfer box. The up-and-down motion of the hand i s provided by a ball-bearing-mounted horizontal axle on a 7-in. -dim by l-l/$-in.-thick depleted uranium disk, which turns with about 1/64-in. clearance i n a cutout i n the above-mentioned cylinder. This gimbal arrangement allows fill freedom of swinging motion of the asm t o any position within a cone of about 40' included angle. The effective shielding thickness of the depleted uranium i s 5 t o 6 in. Au. uranium pieces have hard chrome plating about 0.001 in. i n thickness. The arm is sealed by a 2-ply-polyurethane, conical-shaped, corrugated bellows, about 8 in. i n diameter at the large end and tapering t o about 1 in. in diameter t o the point where it i s clamped at the "wrist" of the arm. Each ply i s about 0.020 in. thick. The space between the inner and outer bellows is maintained below atmospheric pressure. Effluent gas fromthe space passes t o the containment ventilation system, where it is monitored for radioactivity. A cover can, o r cap, is placed over the portion of the manipulator handle extending outside the transfer box when the manipulator is not in use, o r i f gas leakage is detected i n the assembly. This stainless s t e e l can I s about 10 in. i n diameter by 12 in. long and is joined t o the manipulator housing by "Conoseal" multiple T-bolt latches (Catalog Mo. 50765H) and uses a tube-type gasket (Catalog No. 50887-1000S). This can passes the same leak checks as does the transfer box. The can also can be used t o equalize the pressure on the polyurethane bellows when the transfer box i s under pressure or vacuum.

7.3.7.5

V i e w i n g P o r t s and Periscope.

located on the front of the transfer box.

A 4-in.-diam viewing port i s The 1/2-in.-thick

quartz lens

262 I

i s mounted in a pressure-tight, screwed f i t t i n g .

A simple periscope,

using two front-surface mirrors about 2-1/2 by 3 in. and located about

3 ft apart in a 3-in.-square

s t a i n l e s s s t e e l box, i s arranged at a con-

venient height f o r an operator in the standing position.

A knob a t t h e

top has a b e l t drive t o a d j u s t the viewing angle of the lower mirror, and the periscope can be r o t a t e d s l i g h t l y t o view the required portions of the box i n t e r i o r .

The viewing port and t h e lower section of the

periscope are inside the lead shielding which surrounds the t r a n s f e r box.

A hood prevents t h e operator from placing h i s face c l o s e r than

about 7 in. from the upper mirror.

A second quartz l e n s port, i d e n t i c d t o the one described above,

i s located at the top of the t r a n s f e r box i n such a position that the 100-watt e l e c t r i c bulb placed outside t h e box illuminates the work mea.

7.3.7.6

Capsule Removal Valve.

A 2-in. b a l l valve i s located on

the top of the t r a n s f e r box f o r the removal and i n s e r t i o n of the sampletransport container.

The s e a l assembly f o r t h e tube i s described below.

The valve is a Jamesbury Corporation (Worchester, Mass.) t y p DHV-33TT,

w i t h an air-actuated pneumatic cylinder operator No. 04 Model P-100. A &-way solenoid-operated valve controls the air flow t o the cylinder and vents the air t o the atmosphere.

The valve i s enclosed by the lead

shielding around the t r a n s f e r box. b

7.3.7.7

Capsule Removal Tube AssembQ.

The capsule transport con-

t a i n e r i s i n s e r t e d i n t o the removal valve through a s e a l assembly designed t o prevent e n t r y of air i n t o t h e t r a n s f e r box.

The s e a l assembly

a l s o prevents the escape of contaminated gases from t h e box as the cont a i n e r i s withdrawn. The seal i s contained i n a v e r t i c a l s t a i n l e s s s t e e l tube, 2.375-in.-

OD by 11-3/16 in. long, joined w i t h 2-in. 11-1/2 M E T t o the removal valve outlet.

The upper portion i s f i t t e d w i t h a nylon bushing 3 in. long and

w i t h two guiding surfaces, 1.373 in. ID by 3/4 in. long, at each end, through w h i c h the 1.367-in.-oD t r a n s p o r t c a r r i e r tube s l i d e s .

Immedi-

a t e l y beneath the guide bushing a r e two Parker No. 220 neoprene O-ring gaskets, 1-3/8 X 1-5/8 x l/8 in., mounted 1 in. apart.

The space between

t h e gaskets i s d r i l l e d w i t h a 1/16-in.-dia hole and provided with 1/4-in.

L l

30,OoO-lb autoclave tubing f i t t i n g s f o r the introduction of helium purge.

263t

fw A similar tubing connection i s made beneath the O-ring seals for the

connection t o vacuum pump No. 2 or the helium supply (see ORNL drawing 10301-R-152-E) I n operation, the transport container i s first inserted into the s e a l u n t i l the lower end i s below the two O-ring gaskets, the removal valve being closed. 3elium is then introduced between the O-rings, and the space between the seals and the removal valve i s evacuated by vacuum pump No. 2. After helium i s introduced into the space, the removal valve may be opened and the transport container inserted into the transfer box. It i s t o be noted that the removal t o o l is also a leaktight fit into the capsule removal seal.

7.3 8 Capsule Transporting Equipment After taking a sample from the pump bowl, the sample capsule i s placed i n a gas-purged leaktight compartment of a transport container. This container is then withdrawn from the transfer box up into a leadshielded transport cask, using a special tool. The cask i s then taken t o the analytical laboratory. 7.3.8.1 Sample Transport Container. The sample capsules are transported in a 304 stainless s t e e l container assembly, 1.367 in. OD by 18-13/16 in. long, maintained in a v e r t i c a l position f o r both loading and rahipping. The sample capsule rests in a compartment i n the bottom, about 7/8 in. ID by 6 in. long. The compartment fits inside the container, and when the container i s turned by a special tool, i s joined t o it by threads at the bottom of the assembly. Double O-ring, neoprene gaskets seal the Joint. The bottom of the compartment i s notched t o f i t over lugs on a positioning jig in the bottom of the transfer box to keep the compartment from turning when the container i s rotated t o make or break the threaded j o i n t (see OREOL drawing 10301-R-050-E). The upper portion of the transport container i s f i l l e d w i t h an 8-1/4-in.-long plug of lead for shielding in the transport cask, and the upper end has a v e r t i c a l 1/4-in. threaded hole and transverse 5/16-in.diam hole f o r a latching pin, as w i l l be discussed subsequently.

W a

7.3.8.2 Transport Container Removal Tool. The special t o o l used t o insert and remove the transport container and t o rotate it inside the

'264

L+ transfer box i s 1-3/8 in. i n diameter by about 53 in. long.

A 1/2-in0-

diam rod extending through the handle i s threaded w i t h 1/4 in, x 20 UNC

threads at the bottom t o engage the threads a t the top of the container. A 7/16-ine-wide s l o t on the bottom of the t o o l f i t s over a projecting lug on top of the carrier tube t o prevent relative turning. The t o o l is long enough t o extend through the transport cask, the removal valve on top of the transfer box, and into the box f o r joining t o the transport container (see ORML drawing 10301-R-05O-E), 7.3.8.3 Transport Cask. The transport container, with the enclosed sample capsule, i s drawn upward f'rom the transfer box into a shielded transport cask, as sham in Fig. 7.5. The removal tool, described above, i s then disengaged f r o m the transport container. The cask consists of a 25-h. length of 18-in. sched-10 austenitic stainless s t e e l pipe with 3/8-in.-thick f l a t plates welded t o the ends. A 17-l/2-ine length of 2-in. sched-160 pipe at the center serves a s the transport container compartment. Two lugs project from the top of the cask at each side of the central hole. Each lug has a 5/16-in.-diam hole through w h i c h a spring-loaded latching pin operates t o engage the corresponding hole i n the lug at the top of the carrier tube. The pin i s posit i v e l y locked i n place t o prevent accidental removal o r s p i l l s from the cask (see ORNL drawing 10301-R-051-E). The cask i s completely f i l l e d w i t h about 2250 l b of lead t o provide a minimum of 8 in, of shielding i n all directions. The opening at the top of the transport container i s f i l l e d w i t h a lead plug 8-1/4 in. long. The bottom of the cask i s closed w i t h an 8-ine-thick sliding lead door. Lifting trunnions are provided on each side of the cask, which weighs a t o t a l of about 2500 lb. Three casks are available f o r the MSRJ3.

7.4

containment

During all mses of operation, the sampler-enricher system provides a e l m u m of two barriers t o the escape of radioactive particles and gases. Thus, failure of any one component w i l l not r e s u l t i n the release of dangerous amounts of contaminants, a s i s briefly reviewed I

265

Unclassified ORNL DWG 64-8823

Sliding

Figure 7.5.

Transfer Cask f o r Sampler-micher Transport Container.

266 below.

(For a d e t a i l e d description of operation of t h e system, see

Operating Procedures, Fazt V I I I . ) When the sampler-enricher system i s not i n use, t h e operational valve i n t h e t r a n s f e r tube i s closed.

The space between the two s e a t i n g

surfaces i n the valve i s buffered with helium gas a t a pressure g r e a t e r than t h a t i n the pump bowl.

If leakage i n t h e valve does occur, the cap-

s u l e access chamber a t t h e t o p of the t r a n s f e r tube i s sealed with double O-ring gaskets with the space between t h e gaskets buffered w i t h helium gas.

If leakage should occur from t h i s chamber, o r from any of t h e flanged

j o i n t s i n the transfer tube connections, the escaped gases w i l l be cont a i n e d i n e i t h e r the t r a n s f e r box o r the valve box.

These gases are moni-

tored f o r r a d i o a c t i v i t y before being discharged e i t h e r t o t h e a u x i l i a r y charcoal bed or t o t h e containment v e n t i l a t i o n system.

I n preparing t o take a sample, after the t r a n s p o r t container with the empty capsule has been placed i n the removal valve seal assembly and purged of air, the removal valve on the t r a n s f e r box i s opened.

A t this

point i n t h e procedure, t h e operational valve and the access chamber door remain sealed, providing the r e q u i s i t e double containment barrier.

After the t r a n s p o r t container and empty capsule are placed i n the t r a n s f e r box, the removal valve i s closed and buffered with helium gas. (The t r a n s f e r box may then be purged of any entering air should t h i s be necessary.)

When t h e access chamber door i s opened t o l a t c h t h e empty

capsule t o the cable, t h e operational valve remains sealed.

This valve

and the t r a n s f e r box thus c o n s t i t u t e two blocks t o the escape of a c t i v i t y . The access chamber door i s closed and buffered with helium gas be-

f o r e t h e operational valve i s opened t o lower the capsule i n t o the f u e l pump bowl.

The door and t h e transfer box a r e the double b a r r i e r a t t h i s

point. After the sample has been taken and moved t o t h e t r a n s p o r t container i n the t r a n s f e r box, i n the reverse procedure t o that outlined above, helium purge gas sweeps any fission-product gases from t h e t r a n s f e r box t o the a u x i l i a r y charcoal bed.

A t t h e completion of the sampling procedure, when t h e f u e l salt i s contained i n a helium atmosphere inside t h e sealed t r a n s p o r t container located i n t h e t r a n s p o r t cask, the cask i s sealed i n a gas-tight compartment

267

f o r shipment t o the h o t - c e l l f a c i l i t i e s a t the a n a l y t i c a l laboratory.

Double containment i s thus provided during the transport phase.

7.5

Shielding

Preliminary estimates indicated that a f t e r extended operation of the MSRE at 10 Mw, one 10-g samgle of the f u e l salt would have a radi-

a t i o n l e v e l of about 200 r / h r a t a distance of 12 in.

In the design of

the sampler-enricher shielding it w a s assumed that one such sample would be i n the apparatus and that, i n addition, t h e deposits of the decay

daughters of the fission-product gases, particles of f u e l salt, etc., would mount t o about 200 r/hr.

Figure 7.6 indicates the estimated ap-

proximate dose rate at t h e surface of the shielding f o r varying thicknesses of lead. The outside of the sanpler-enricher valve box, t r a n s f e r box, etc.,

i s shielded w i t h a minimum thickness of 8 in. of lead, mostly i n t h e form of stacked lead bricks.

As described i n Section 7.3.7.4,

pulator i s shielded w i t h 6 in. of depleted uranium.

the mani-

During maintenance,

w i t h no sample i n the apparatus and the r a d i o a c t i v i t y due only t o res i d u a l contamination, it i s estimated that 6 in. of lead shielding i s s u f f i c i e n t after a &-day decay period. 5

The sleeve opening through the reactor containment v e s s e l shielding, through which the t r a n s f e r tube passes, requires special consideration.

As mentioned i n Section 7.3.5.2, the annular space between the sleeve w a l l and t h e transfer tube is f i l l e d with a 20411. length of lead. In addition, stacked blocks of borated polyethylene, lead bricks, etc.,

are

used t o attenuate and absorb the beam coming through the opening.

7.6

Stresses

The s t r e s s e s i n the valve and t r a n s f e r boxes were investigated ie using standard relationships. The design pressure w a s 40 p s i g a t room

*Private communication, Ralph D. Frey t o R. B. Gallaher, December 1963.

268

Unclassified

50 30

3 2

1 9)

0.5

0.3 0.2

0.1

Figure 7.6.

Effect of Lead Thickness on Effectiveness of S~pllplershielding.

8 Thickness of Lead

- in.

.........--. .....** . .... ......_..*".

...............

.......................

.__ . .~.. .

269

temperature, and 18,750 p s i was taken as the allowable s t r e s s i n 304

Ilr

stainless

The applicable ASME Codes a r e l i s t e d i n Section 7.2.6.

Reinforcing ribs a r e used f o r t h e sides and cover p l a t e s and the openings

are reinforced where required. Investigation of the t r a n s f e r tube indicated a maximum bending stress of about 9200 p s i at one end. 129

7.7 Cover-Gas and Leak-Detection System Helium i s used i n the sampler-enricher system t o purge the sealed c

compartmnts of air o r contaminated gases, t o operate the pneumatic door

latches on the capsule access chamber door, and t o pressurize, o r buffer,

the space between the double gaskets used throughout. c

A drop i n the

helium supply pressure t o the l a t t e r , indicating a leak, actuates the

various interlocks in the control c i r c u i t s .

As shown i n Fig. 7.7 (Instrument Application D i a g r a m , ORNL drawing D-HB-B-b505), helium i s supplied t o the f i e 1 and coolant salt samplerenricher equipment a t 250 p s i g through l i n e s 509 and 515, respectively, from l i n e 514 i n the west tunnel area (see Section 10).

With but f e w ex-

ceptions, a l l helium l i n e s i n the sampler-enricher system are 1/4-in.-OD by 0.083-in. -wall-thickness s t a i n l e s s s t e e l tubing w i t h 30,OOO-lb autoclave f i t t i n g s .

A l l helium supply l i n e s have double check valves t o pre-

vent backf low. A t the f u e l - s a l t sampler-enricher control board, l i n e 509 divides

i n t o l i n e s 650 and 674.

The former has a pressure-reducing valve, w-650,

which Furnishes helium a t 75 psig t o 3-way solenoid valves XSV-652 and

HSV-653, each of w h i c h supplies three of the pneumatic clamps t o close and l a t c h the capsule access chamber door.

After the doors a r e latched,

the 3-way valves vent the spent helium t o the containment v e n t i l a t i o n system, as w i l l be described subsequently.

The doors are unlatched and

opened by the admission of helium through HSV-651, a 3-way valve a l s o supplied from l i n e 650. Line 674, mentioned above, i s provided w i t h helium through a pressure y'

* k

c o n t r o l valve, W-509, which reduces the pressure t o b psig and supplies two headers,

664 and 683, which have branch l i n e s t o the various seals,

....... . ^

....

l_._-l_,_,ll-__.

....._ * _ .... _

........

. . . . .._

. . . . . . . . . . . . . . . . . .

I I I

271

flanged j o i n t s , e t c .

Most of the branch l i n e s contain a flow element

consisting of a short length of c a p i l k r y tubing, t o r e s t r i c t the f l o w P

should a buffered j o i n t develop a s i g n i f i c a n t leak.

In t h i s event, the pressure drop i n e i t h e r of the two headers, 664 o r 683, would be sensed by pressure i n d i c a t o r s and an alarm would be sounded. The branch l i n e s and the data on each r e s t r i c t o r are tabulated i n Table 7.1. Line 674 a l s o supplies helium at 40 psig t o l i n e 672, which provides a supply of purge gas f o r the t r a n s f e r box. The r e l a t i v e l y large f l o w is regulated through PV-672, rather than through a r e s t r i c t o r tube. Two check valves i n s e r i e s at the e x i t of the l i n e inside the box pre-

vent backflow of possibly contaminated gas.

(The l i n e between the check

valves and w-672 can be evacuated by vacuum pump No. 2 and the gas discharged t o the containment v e n t i l a t i o n system. ) The cable drive box i s supplied w i t h helium a t 40 psig from l i n e

674, v i a l i n e 657. This l i n e i s provided w i t h a flow r e s t r i c t o r , as l i s t e d i n Table 7.1. The helium flows through the drive box t o the capsule access chamber, and i s vented through l i n e 678, as discussed below. Line 666, branching from l i n e 674, i s provided w i t h a pressureregulator, W-666, which reduces the pressure t o 15 p s i g for the helium supply between the double O-ring seals a t the transport container s e a l .

7.8 Off-Gas System Off-gas from the capsule access chamber and transfer box is vented through vacuum pump No. 1 t o the a u x i l i a r y charcoal bed.

All other gas,

some of which may pass through vacuum pump No. 2, i s vented t o t h e containment v e n t i l a t i o n system. A l l discharged gas i s monitored f o r radioa c t i v i t y both at t h e sampler-enricher s t a t i o n and again i n the MSRE: gas disposal systems. A l l off-gas l i n e s leading t o the charcoal beds can be blocked w i t h two valves i n s e r i e s .

7.8.1

System No. 1 The capsule access chamber i s vented through l i n e 678, which i s

provided with valves HCV-678 and HSV-678. Gas i n the t r a n s f e r box i s

h-, L

vented through HCV-677 and l i n e 677, which j o i n s l i n e 678 t o connect t o

Table 7.1.

Helium Supply Lines and Restrictors in Fuel-Salt Sampler-Enricher System Restrictor

ax. F ~ WRatea Line No.

Equipment Supplied

(cc/min STP)

650

Capsule chamber door Latches Maintenance valve buffer Cable drive box Buffer seals Removal seat buffer Operating valve buffer

5000

655 657 664 666 668 669 670

Capsule chamber door buffer Removal valve buffer

30 5000

30 30 30 30

Inlet (psig)

75 40 40 40 15 40 40 40

(in.)

Tube Lengthb (in.)

0.012

0.060

10.8

0.006 0,017 0.006 0.006 0.006 0.006 0.006

0.050 0.060 0 050 0.050 0.050 0-050 0.050

28 12.4 28

9.5 28 28

a A l l restrictors discharge at essentially atmospheric pressure. b A l l restrictors have tubing formed into a c o i l and contained within a 2-in. length of 2-in. sched-40 pipe capped at each end. A l l material i s 304 stainless steel.

2 73.

the suction of vacuum pump No. 1, a f t e r passing the radiation monitor RE-678. The vacuum pump discharges through a check valve t o line 542, which connects t o l i n e 52lleading t o the auxiliary charcoal bed described in Section 12.4.2. The vacuum pump i s a W. M. Welsch Manufacturing C o w "Duo-Seal" unit, Model 1402, having a capacity of 140 liters/STP and is driven by a 1/4-hp motor. The punrp i s located i n a vented box at the rear of the sanrpler-enricher u n i t . 7.8.2 T

System No, 2

The pneumatic cylinders on the capsule access door latches exhaust through the 3-way solenoid-operated valves HSV-651, 652, and 653, through HW-675 and line 675, past the radiation monitors RE-675A and RE-675B, and joins the 9-in.-diam line 949 leading t o the containment ventilation system described i n Section 13. The box in which vacuum pump No. l i s located i s vented throu@;h line 660 t o the containment ventilation system, via line 684. A branch of l i n e 684 dram gases from the vacuum pump No. 2 vented box. The valve box i s vented t h r o u e line 659 t o the vacuum pump No. 2 box. A remotely operated valve i n this line, H~V-659,permits the l i n e t o be closed t o determine which of the compartments i s the ~ o u r c eof cattamination, should this be indicated by radiation monitors RE-675 A&B. Air o r contaminated gases in the removal tube assembly are &awn off through l i n e 679 an8 valve HCP-679, t o the intake o f vacuum puarp 100. 2. This p u q tiischarges into the vented box in which it is located, t o be vented through l i n e 684, mentione8 above. Vacuum pump No. 2 i s identical t o the No. l u n i t , described above. Both pumps are operated only when the sampler-enricher equipment i s in use

7.8.3

Exhaust Hood

An exhaust hood i s located over the transport cask position on the sampler-enricher t o d r a w off any fission-product gases which mi@ escape. This hood i s connected to the containment ventilation exhaust system, tbe air being drawn from the high-bay area, as described i n Section 13.

274

7.9

Electrical

Electrical power for the sampler-enricher system is supplied from the 25-kw dc-ac motor-generated s e t No. 4, v i a instrument power panel No. 2 . fn event of failure of the dc supply normally driving the motorgenerator set, batteries can provide at l e a s t two hours of running time,

as described in Section 19. The capsule cable drive motor i s arranged f o r U-0-v, single-phase operation. The 220-v, 3-phase power f o r the operational and maintenance valve-control motors i s obtained from a s t a t i c converter used t o change the single-phase parer from the 25-kw motor-generator s e t t o 3-ghase. Mineral-insulated e l e c t r i c a l leads are used at a l l points where w i r e s must pass t h o u @ the w a l l s of the leaktight compartments. All e l e c t r i c a l disconnects are located outside the containment areas. 7.10

Coolant-Salt W l e r - E n r i c h e r System

Salt samples are taken fromthe coolant-salt pump bowl i n es-

sentially the same manner as t h a t used i n the fuel-salt system. Samples are removed but about once a month, however, and single, rather than double, containment is sufficient in that long-lived radioactive material i s not normally present in the coolant-salt pump bowl. The same sampling capsules are used in the f u e l and coolant-salt systems, see Section 7.3.1.2 and Fig. 7.1. The transfer tube, capsule drive mechanism, capsule latch, pump bowl internals, including the sampling cage, are all identical t o those used i n the fuel-salt system. See Sections 7.3.2 through 7.3.5 and 7.3.7.2. The 1-1/2-in. NPS transfer tube extends from the coolant-salt pump bawl upwards through the side of the penthouse t o a dry box mounted in

a "packaged" coolant-salt saJnpUng unit, !J!he dry box is a 3O-in.-long vertical section of %in. sched 40 pipe. The pipe is closed at the bottom with a pipe cap and at the top w i t h a l5O-psi hinged and. clamped flanged Tubeturn closure having elastomer O-ring seals. This dry box houses the capsule drive unit. The box i s provided with one rubber glove, the opening f o r which can be sealed w i t h an 8-in. hinged flange

275

similar t o that used on the top of the box. A 1-1/2-in. NPS connection at the bottom leads t o the two 2-in. Janesbury b a l l valves (see Section 7.3.7.6) in the transfer tube, and a top connection i s provided for the 1-1/2-in. b a l l valve f o r insertion and removal of the capsules. The box i s also equipped w i t b two 3-in.-dia~n quartz-lens viewing and illuminating ports, helium and vacuum connections. See ORIVL drawing 10333-R-002-E. The dry box was desigued f o r a vacuum o r for 40 psig at IOOOF in accordance w i t h the ASME Code f o r s e c o n m nuclear vessels. 49 m e normal operating pressure is 5 psig. A system of s i x different keys and about nine locks i s used on the valves, e l e c t r i c a l switches, opening latches, etc., t o reduce the l i k e l i hood of using an improper operating sequence. This system of "key interlocks" operates on the principle that a key is used t o unlock a device and also t o gain access t o a key which can be used t o unlock the next step in the procedure. An e l e c t r i c a l system sounds an &mn i f the pressures i n the equipnmt are not suitable f o r the next step t o be undertaken. The sample capsules are inserted into the Cxry box from, and w i t h drawn from the box into, a portable container which i s used t o transport the samples t o the analytical laboratory i n an i n e r t atmosphere. This container is a short section of 1-1/2-in. pipe w i t h a 1-1/2-in. Jamesbury b a l l valve at the bottom and a Wilson, Teflon, sliding dynamic vacuum s e a l where the 1/4-in.-diam raising and lowering rod passes through the top cap

In brief, the samples are taken by first evacuating the glove and the d r y box by mans of the vacuum pump provided in the packaged system. The gases are exhausted t o the containment ventilation system filters and stack. The box i s then purged w i t h helium, a f t e r w h i c h the sample i s lowered from the transport container which has been temporarily mounted on the b a l l valve on top of the dry box. The flange cover on the dry box glove is then opened, allowing the operator t o insert his hand and t o attach the capsule to the latch on the capsule drive cable. After the capsule has been lawered into the pump bowl and filled, it i s retained i n the transfer tube f o r about ten minutes t o allow the salt to solidify and the activity t o decay. It is then raised into the d r y box and the reverse sequence of procedures used t o transfer the capsule t o the transport container. The operation i s described in d e t a i l in Part V I I I .

277

8. COOLANT-SALT CIRCUUTING SYSTEM

8 :l Layout and General Description The coolant-salt system t r a n s p o r t s r e a c t o r heat from t h e f u e l s a l t heat exchanger t o the air-cooled r a d i a t o r where t h e energy i s d i s s i p a t e d t o t h e environment by t h e discharge of warm a i r from t h e stack.

* coolant s a l t , o r secondary

"he

, system c i r c u l a t e s a lithium and beryllium

s a l t , s i m i l a r i n physical p r o p e r t i e s t o t h e f u e l salt but barren of f i s -

sionable materials (see Table 2.1).

are t h e f i e 1 s a l t heat exchanger, located i n t h e r e a c t o r c e l l and de-

The main components i n t h e system

scribed i n Section 5.5, t h e coolant-salt c i r c u l a t i n g pump and t h e radi-

a t o r , both located i n t h e coolant salt c e l l . The coolant-salt c i r c u l a t i n g pump i s very similar t o the f'uel s a l t pump described i n Section 5.4.

Both pumps use a 75-hp motor, but t h e

coolant salt pump operates against a higher head of 78 f't, t u r n s a t ,a higher speed of 1750 rpm, and d e l i v e r s only 850 gpm as compared t o 1250 gpm @ r t h e f u e l pump.

Other differences a r e that t h e coolant s a l t pump

does not have t h e cooling shroud f o r t h e top portion of pump bowl, spray nozzles i n t h e bowl f o r r e l e a s e of fission-product gases, and t h e overflow tank.

The pump bowl has a c e n t e r l i n e elevation o f 833 ft 6 i n . ,

and as t h e highest point i n t h e coolant salt system, serves a s an expansion volume.

It is located i n what i s sometimes r e f e r r e d t o as t h e

penthouse area. The r a d i a t o r has 120 tubes, 3/4-in. diam x 30 ft long, arranged i n serpentine c o i l s t o provide 706 ft2 of heat t r a n s f e r surface.

salt e n t e r s a t llOO°F and leaves a t 1025'F

The coolant-

a t 10 Mw design conditions.

r!ioo&d&gngir-.3ii.ssuppl-bd: by two 250-hp axial blowers located i n t h e blower house and having a combined capacity o f about 200,OqO

cfm.

The

leaving a i r , heated a t design conditions t o about 300°F, .is discharged from-the e x i s t i n g 1O-f% diam x 75-ft-high steel s t a c k a t t h e southwest corner o f Bldg. 7503.

To guard against fYeezing o f t h e coolant salt i n

*MSRE l i t e r a t u r e occasionally r e f e r s t o t h e coolant s a l t equipment as t h e secondary system.

The

278 t h e r a d i a t o r tubes on reduction of power o r loss of c i r c u l a t i o n , quickclosing doors are provided f o r t h e r a d i a t o r t o close o f f t h e a i r flow, and t h e r a d i a t o r assembly includes e l e c t r i c heaters inside the enclosure. A bypass damper and duct permits regulation of t h e a i r flow over t h e

coil. The 5-in. pipe f i o m t h e coolant-salt pump discharge e n t e r s t h e r e a c t o r c e l l through a penetration on t h e south s i d e and c i r c l e s t h e c e l l on t h e e a s t s i d e t o t h e f u e l heat exchanger i n l e t opening t o t h e tube s i d e A t 10-Mw t h e coolant salt enters t h e enchanger a t about 1023'F

a t about 1100'F.

and leaves

The e x i t coolant s a l t l i n e c i r c l e s t h e c e l l on t h e west

s;ide, leaves through a penetration on t h e south s i d e a t about t h e 836-st l e v e l , and then r i s e s t o t h e i n l e t header a t t h e top of t h e r a d i a t o r . The coolant-salt piping has low points on each s i d e of t h e r a d i a t o r , therefore two 1-1/2-in. coolant-salt d r a i n tank.

d r a i n l i n e s a r e provided.

These leah t o t h e

A 1/2-in. bypass l i n e vents gas flrom t h e top

of t h e r a d i a t o r when f i l l i n g t h e system with s a l t .

This l i n e has no

valves, t h e s a l t bypass flow being inconsequential. A l l p a r t s of t h e coolant-salt c i r c u l a t i n g system can be maintained

above t h e liquidus temperature of t h e s a l t , about 85O0F, by means of e l e c t r i c heaters.

The heaters on t h e coolant-salt piping inside t h e r e -

a c t o r c e l l a r e removable f o r maintenance i n t h e same manner a s pipe l i n e heaters on t h e f u e l salt system, see Section 5.6.4.

Heaters f o r t h e

coolant-salt system located outside t h e r e a c t o r c e l l can be approached f o r d i r e c t maintenance a short time a f t e r r e a c t o r shutdown.

Pipe l i n e

heaters a r e attached tubular types with standard i n s u l a t i o n .

Heaters

i n s t a l l e d i n s i d e t h e c e l l w a l l penetrations can be maintained from the coolant c e l l s i d e . The coolant-salt piping i s anchored a t t h e c e l l wall penetrations,

a t t h e coolant-salt c i r c u l a t i n g pump and a t t h e r a d i a t o r .

The piping

runs between these points a r e s u f f i c i e n t l y f l e x i b l e t o absorb t h e thermal expansion.

This arrangement eliminates t h e need f o r t h e r a t h e r elaborate

f l e x i b l e support system f o r t h e pump, as i s used i n t h e f u e l system, and a l s o permits t h e r a d i a t o r s t r u c t u r e t o be r i g i d l y mounted. Auxiliary equipment f o r t h e coolant-salt c i r c u l a t i n g system includes t h e helium cover gas supply, t h e off-gas system, t h e bubbler l i q u i d l e v e l

279

system, t h e lubricating o i l system for t h e pump, cooling water, e t c .

The

coolant-salt drain tank f o r storing t h e charge of s a l t i n t h e c i r c u l a t ing system is located almost d i r e c t l y beneath t h e radiator and i s described i n Section 9. A l l salt-containing portions of t h e system a r e constructed of INOR-8,

see Table 2.2. 8.2 Flowsheet The coolant-salt circulating system and t h e coolant s a l t d r a i n system a r e shown i n Fig. 8 .L (OWL Dwg D-AA-A-40881). When operating a t t h e 10-Mw reactor design power l e v e l , t h e coolant s a l t c i r c u l a t i n g pump discharges about 8% gpm of s a l t a t lO25OF and about

70 psig i n t o t h e 5-in. sched 40 l i n e 200. A t lower power l e v e l s t h e t e m perature w i l l increase and a t zero power w i l l be 1200°F t o l225'F.

Line

200 enters t h e reactor c e l l and is connected through fkeeze flange F-200 t o t h e f u e l heat exchanger, see Fig. 5.3 (ORNL D-AA-A-40880).

Line 200

has three heater sections and t h i r t e e n thermocouples within t h e coolant c e l l , and twelve heater s'ections and seventeen thermocouples inside t h e reactor c e l l .

The penetration through t h e c e l l w a l l contains eight heat-

e r s and seven thermocouples. y:

The f u e l system process flowsheet indicates

a future freeze flange i n t h e reactor c e l l a t the wall penetration,

This

new flange would be required should it become necessary t o replace l i n e 200.

The coolant-salt leaves t h e heat exchanger through t h e 5-in. sched

40 pipe, l i n e 201, a t about 1,lOOOF and 47 psig.

After passing through

t h e freeze flange FF-201, and the c e l l w a l l penetration, it returns t o t h e coolant c e l l .

Line 201 i s provided with heaters, thermocouples, and

has provisions for a future freeze flange, i n t h e same manner as l i n e 200, described above. A f t e r passing through a venturi, FRA-201, t o indicate t h e flow r a t e ,

t h e coolant-salt enters t h e top header of the radiator a t a pressure of about 36 psig.

The radiator has 120 tubes, 3/4 i n . OD 0.072-in. w a l l

thickness x 30 f t long, arranged i n serpentine c o i l s between two headers, t o provide a t o t a l of about 706 t'f

of heat t r a n s f e r surface.

The pressure

c-i

r 2

I I

(pa

I I I I I I I I

281

bd 1

drop of tk. coolant-salt i n flowing through t h e r a d i a t o r tubes i s 20 p s i .

There a r e 149 thermocouples i n s t a l l e d , which includes one thermocouple for each tube so that a plugged flow passage can be detected.

The re-

maining thermocouples on the r a d i a t o r i n l e t and o u t l e t headers provide data f o r heat balances used t o determine t h e reactor power.

The radia-

t o r u t i l i z e s eight heater c i r c u i t s . The r a d i a t o r i s cooled by a flow of 200,000 cfh of a i r supplied by two 250-hp motor-driven a x i a l b l o w e r s .

The a i r i s d r a m through t h e

louvered sides of t h e blower house and delivered t o t h e r a d i a t o r c o i l face a t a pressure of about 10 i n . of H20. Each blower has a motoroperated a x i a l damper which can be closed t o prevent back flow.

The

a i r i s heated about 200°F i n passing through t h e r a d i a t o r c o i l and, af'ter f

passing through turning vanes, i s discharged up t h e 10-f't diam x 75-f't high s t e e l s t a c k .

The s t a c k has a p i t o t F v e n t u r i tube, FI-AD3, t o measure

t h e a i r flow and t o enable heat balances t o be made on t h e heat rejeckion system.

The by-pass damper and t h e r a d i a t o r doors a r e used t o a d j u s t t h e

a i r flow across t h e c o i l t o e s t a b l i s h t h e desired heat removal r a t e and, thus, t h e power l e v e l a t which t h e r e a c t o r operates. The coolant-salt leaves t h e bottom header of t h e r a d i a t o r a t about

1025'F

and 23 p s i g and returns t o t h e c i r c u l a t i n g pump v i a l i n e 202, a

5-in. sched 40 INOR-8pipe.

The heaters for t h e l i n e a r e l i s t e d i n Table

7.12, Section 5.6.6.

The s a l t enters t h e bottom o f t h e pwap b o w l w h e r e any entrained gases a r e drawn o f f .

A 3-psig over-pressure of helium i s maintained above t h e

salt l e v e l i n t h e bowl, t h e helium being introduced through l i n e 512 and

t h e l i q u i d l e v e l bubbler l i n e s .

About 15 gpm of t h e 850 gpm discharge

r a t e of t h e pump r e t u r n s t o t h e pump bowl by escaping through t h e clear? ances between t h e impeller and t h e casing, t h e so-called "fountain flow'' described i n Section 5.4.1.2. The pwrrp operates against a head of 78 ft and t h e discharge pressure i s 70 p s i g .

The pump discharges i n t o l i n e

200, described previously as leading t o t h e heat exchanger inside t h e

reactor c e l l . The 1-1/2-in. sched 40 fill and drain, l i n e 204, i s connected t o t h e low point of elevation i n l i n e 201.

A similar drain, l i n e 206, i s

provided for t h e l o w point i n t h e r a d i a t o r a t t h e lower header.

Both

282 of these l i n e s have Freeze valves, FV-204 and FV-206, and connect t o t h e coolant-salt d r a i n tank through l i n e 204.

di &

This l i n e i s provided with a

reservoir, consisting of a 5-in. length of b i n . sched 40 pipe w i t h pipe caps welded on each end, which insures t h a t a s u f f i c i e n t quantity of salt

w i l l remain behind a f t e r a d r a i n t o completely f i l l t h e freeze valves so that a s e a l can be effected.

Each of t h e

(See ORNL Dwg E-GG-C-40603).

drain l i n e s , 204 and 206, has one heater c i r c u i t and seven thermocouples on t h e c i r c u l a t i n g system s i d e of t h e flreeze valve. The coolant-salt d r a i n tank i s located beneath t h e r a d i a t o r and has s u f f i c i e n t capacity t o s t o r e t h e 44 ft3 o f s a l t contained i n t h e circuk

l a t i n g system.

The drain tank i s described i n Section 9, following.

Line 205 i s a 1/2-in. sched 40 pipe which connects t h e high point o f t h e i n l e t l i n e t o t h e r a d i a t o r , l i n e 201, with t h e o u t l e t , l i n e 202, t o vent t h e gas from l i n e 201when f i l l i n g t h e system w i t h s a l t . s i g n i f i c a n t amount of s a l t i s by-passed through l i n e 205.

An in-

The pipe has

one heater c i r c u i t and two thermocouples. Thirteen a u x i l i a r y pipes connect t o various p a r t s of t h e coolant-

s a l t c i r c u l a t i n g pump.

Lines 594, 595 and 598 a r e 1/4-in. OD s t a i n l e s s

s t e e l tubes carrying helium f o r t h e bubblers and t h e reference pressure f o r determining t h e s a l t l i q u i d l e v e l i n t h e pump bowl.

The noma1

helium flow r a t e i n l i n e 594 i s 0.15 liters/min, and i n l i n e s 595 and

598 i s 0.37 liters/min.

The solenoid valves i n these l i n e s a r e i n t h e

coolant c e l l and t h e hand control valves and flow indicators a r e i n t h e s p e c i a l equipment room. Line 512 i s a 1/4-in. OD s t a i n l e s s s t e e l tube supplying 0.6 l i t e r s / min of helium purge gas t o the pump shaft annulus j u s t below t h e lower shaft; s e a l , t o provide an i n e r t cover gas, t o provide off-gas t o t h e r a d i a t i o n monitor, and t o reduce t h e migration of o i l vapor t o t h e coolant

salt i n t h e bowl. Off-gas i s vented f r o m t h e pump bowl a t an estimated r a t e of 1.4 liters/min through t h e 1/2-in. l i n e 528.

The gases a r e a t a pressure of

about 5 p s i g and flow through a f i l t e r and a pressure-regulating valve, PCV-528.

By controlling t h e r a t e of venting t h e gases, t h i s valve es-

t a b l i s h e s t h e operating pressure i n t h e coolant-salt system.

Line 528

continues t o t h e vent house where, a f t e r passing t h e r a d i a t i o n monitor

283

RIA-528, it j o i n s l i n e 927, v i a l i n e s 565, 53' and 560, t o be vented through t h e f i l t e r s and t h e off-gas stack. The small o i l leakage through t h e lower s h a f t s e a l on t h e p q i s

swept away by 0.07 liters/min of helium t h a t flows upwards through t h e labyrinth s e a l and out through l i n e 526.

The 1/2-in. pipe leads t o an

o i l catch tank i n t h e coolant-salt d r a i n c e l l where t h e separated o i l drains i n t o a 55-gal s t a i n l e s s s t e e l drum.

The helium vent pipe con-

tinues as l i n e 526 through a hand valve, V-526, a f i l t e r , and a 304 s t a i n l e s s s t e e l c a p i l l a r y r e s t r i c t o r which l i m i t s t h e flow t o about 70 cc/min.

The vented gas joins t h e above-mentioned l i n e 328 f o r discharge

through t h e f i l t e r s and t h e off-gas stack. The coolant-salt i s sampled through l i n e 998, which is a 1-1/2-in. sched 40 pipe r i s i n g v e r t i c a l l y from t h e pump bowl and i n t o t h e high bay S a l t i s dipped from t h e bowl and withdrawn through a b a l l valve,

area.

ECV-998, in t h e same manner as described f o r t h e f u e l pump i n Section 7, with t h e exception t h a t t h e lower a c t i v i t y l e v e l allows t h e coolant-salt system t o be somewhat l e s s complicated. Iubricating o i l i s supplied t o t h e pump bearings through t h e 3/4-in.

l i n e 753 a t a r a t e of about 8 gpm through t h e 3/4-in. l i n e 754.

The o i l

leaves t h e s h i e l d block through l i n e 757, i n which t h e o i l temperature i s monitored, and passes through an eductor t o induce a flow of o i l from t h e bearings through l i n e 755.

The combined o i l flow leaves t h e c e l l

through t h e 1-in. l i n e 756, and returns t o t h e coolant-salt lubricating

o i l system.

Line 591 i s a 1/2-in. pipe connecting t h e top of t h e l u b r i c a t i n g o i l supply tank with t h e topmost passages of t h e bearing housing t o equalize t h e pressure between t h e two points. f O C .the

The l u b r i c a t i n g o i l system

coolant-salt pump i s e s s e n t i a l l y t h e same as f o r t h e f i e 1 pump,

as described i n Section 5.4.1.4. The coolant-salt pump is driven by a 75-hp, 1,750 rpm, ~ O - V , threephase e l e c t r i c motor,

The motor i s i n s t a l l e d i n a s t e e l housing that

w i l l contain o i l and radioactive gases i f e i t h e r o r both were t o leak through t h e upper s e a l i n t h e bearing housing.

The motor i s cooled by

5 Qpm of t r e a t e d water supplied through l i n e 832 and leaving through l i n e 833. A microphone, XdbE, permits monitoring o f t h e pump noise

284

b level.

The motor speed, SIA CP-G,

e l e c t r i c a l input, E i I , EVE, %-I, and

temperatures a r e a l s o monitored.

The r a d i a t o r i s cooled by a 200,000-cfm flow of a i r supplied by two 250-hp motor-driven a x i a l blowers.

Each blower has motor-operated damp-

e r s which close t o prevent back flow.

The a i r i s drawn through t h e lou-

vered openings i n t h e blower house walls and delivered t o t h e c o i l face a t

a pressure of about 9.9 i n . H20.

The a i r i s warmed about 200°F by t h e

heat r e j e c t e d from t h e cooling s a l t , and a f t e r leaving t h e c o i l passes through turning vanes and flows upwards through t h e 10-f’t-diam x 75-rthigh s t e e l discharge stack.

The s t a c k i s provided with p i t o t - v e n t u r i

tubes which can t r a v e r s e t h e s t a c k f o r flow measurements t o e s t a b l i s h I

heat balances f o r t h e heat r e j e c t i o n system, FI-AD (See P a r t 11). The by-pass damper and t h e r a d i a t o r i n l e t and o u t l e t doors a r e used t o a d j u s t t h e a i r flow across t h e radiator c o i l face t o f i x t h e heat removal r a t e f’rom t h e coolant s a l t and,$ oonsequentially, t h e power l e v e l a t which t h e r e a c t o r operates. Two 10-hp a x i a l blowers located i n t h e blower house discharge 10,000 c f h each of a i r i n t o t h e annular space between t h e r a d i a t o r a i r duct and t h e building w a l l s t o prevent damage t o t h e building s t r u c t u r e and r a d i a t o r duct.

This i s p a r t i c u l a r l y necessary when t h e r e a c t o r i s oper-

a t i n g a t zero o r very low power l e v e l s and t h e main blowers a r e o f f .

. -.

285

8.3 Coolant -Salt Circulating pu~llp The coolant-salt c i r c u l a t i n g pump is i d e n t i c a l i n most respects t o t h e fuel s a l t c i r c u l a t i n g pump. The two pumps were fabricated t o e s s e n t i a l l y t h e same drawings and specifications with t h e various p a r t s and subassemblies supplied by t h e same manufacturers.

(See Section 5.4)

Development of t h e coolant pump, f i n a l assembly and t e s t i n g proceeded a t ORNL almost concurrently with work on t h e f'uel pump. The pump bowl i s t h e highest point of elevation i n t h e coolant-salt c i r c u l a t i n g system and, s i m i l a r l y t o t h e f u e l c i r c u l a t i n g system, serves as a surge volume, as t h e point f o r pressurizing t h e system w i t h t h e

helium cover gas, and as a means of separating and venting of gases ent r a i n e d i n t h e salt stream. The f u e l and coolant-salt pumps a r e both c e n t r i f u g a l sump types, driven by direct-connected motors, and d i f f e r mainly i n t h e i r hydraul i c c h a r a c t e r i s t i c s through having d i f f e r e n t operating speeds and i m p e l l e r diameters.

Because of t h e lower l e v e l of r a d i o a c t i v i t y i n t h e

coolant-salt, t h e coolant pump has no provisions f o r cooling of t h e upper portion of t h e bowl, and does not include t h e "stripper" flow i n t h e bowl f o r removal of fission-product gases.

Unlike t h e fuel pump i n

t h e r e a c t o r c e l l , t h e coolant pump can be approached f o r d i r e c t maintenance a short time a f t e r r e a c t o r shutdown, a f e a t u r e which simplified flange b o l t i n g arrangements, e l e c t r i c a l disconnects, pump bowl heater design, thermal insulation, e t c .

8.3.1 Description Fig. 2.3 serves as a general i l l u s t r a t i o n of both t h e f u e l and coolant salt pumps. (See ORNL coolant pump assembly Dwg F-2-02-09-

10062-€&) .

The general location of t h e pump i n t h e coolant c e l l i s

shown i n Figs. 4.4 and 4.5. The coolant pump has a design capacity of 850 g p m a t a head of 78

t'f

when driven a t l75O r p m by a 75-hp motor.

Other design d a t a a r e

given i n Table 8.1 WRNL drawings f o r t h e MSRE pumps have a d i f f e r e n t numbering system than t h a t used for a l l other E R E drawings.

286 Table 8 .l. Coolant-Salt Circulating Pump Design flow:

pump output, gpm i n t e r n a l bypass, g p m

Design head a t 850 gpm, f’t Design discharge pressure, p s i g Design intake pressure, p s i g Impeller diameter, i n . b

Speed, r p m Intake nozzle (sched 40), i n . IPS

Discharge nozzle (sched 40), i n . IE’S

Pump bowl:

diameter, i n . height, i n .

Volumes, f’t 3

Minimum s t a r t i n g and normal operating (including volute )

4.1

Maximum operating

5 -2 6.1 2 .o 8.6 75

Maximum emergency (includes space above vent ) Normal gas volume Overall height of pump and motor assembly, f’t Design conditions:

pressure, p s i g temperature,

1300

Estimated r a d i a t i o n l e v e l a t pump, r/hr

1 4,

Motor:

Rating, hp E l e c t r i c a l supply (AC),

volts

440

S t a r t i n g (locked r o t o r ) current, amps

450 Squirrel-cage induction

NEMA c l a s s

Lubricant (Calif. Research Corp ) Electrical insulation class Design r a d i a t i o n dosage f o r e l e c t r i c a l insulation, r

m~-159 H

2 x 1o1O

*Actual capacity i s between 850 and 940 gpm and maximum discharge pressure i s 75 p s i g a t 1765 r p m . (See Ref. 8.3.1)

287 All p a r t s of t h e pump i n contact with t h e coolant salt are fabricated of INOR-8.

The pressure-containing portions were designed f o r

75 psig and 1300°F and i n accordance with Section V I 1 1 of t h e ASME Un48 and

f i r e d Pressure Vessel Code,47 Code h t e r p r e t a t i o n Cases l270N

1273N.50 The thermal s t r e s s e s were evaluated on t h e same basis a s f o r t h e f u e l - s a l t pump, see Section 5.4.4 and R e f . 88. The coolant-salt pump i s arranged i n t h r e e p r i n c i p a l assemblies: t h e r o t a r y element, t h e pump bowl, and t h e d r i v e motor. The r o t a r y element assembly includes t h e r o t a t i n g shaft and impeller, t h e bearing housing and bearings, and t h e impeller cover p l a t e and upper labyrinth subassersbly.

The bearings, seals, and lubrication and helium

gas passages, a r e a l l of t h e same type and arrangement as i n t h e f u e l pump. (See Section 5.4.1.1). The impeller diameter i s 10.33 i n . and is provided w i t h t h e same type of impeller shroud as t h e f u e l pump. Pump speed and noise pickups a r e e s s e n t i a l l y t h e same as i n t h e f u e l

system. The l u b r i c a t i n g o i l system for t h e pump i s i d e n t i c a l t o t h a t use t f o r t h e f u e l pump, although t h e heat r e j e c t e d i n t h e o i l cooler i s much See Table 5.6 and t h e l u b r i c a t i o n system flowsheet, Fig. 5.25 ( O W L Dwg D-AA-A-40885). The same o i l i s used as a lubricant i n both

less.

systems, see Table 5.7.

The l u b r i c a t i n g o i l systems are separate from

each other, although located adjacent t o each other i n t h e e a s t tunnel I

i *

a r e a j w i t h t h e exception t h a t i n an emergency Lines 762, 712 and t h e breather interconnection, Line 601, allow e i t h e r lubricating o i l system

t o supply both pumps. The pump bowl, pump volute and discharge thimble i n t h e bowl a r e almost i d e n t i c a l t o t h e f u e l pump components. length of @-in.

The thimble has a b i n .

OD tubing welded t o t h e top t o vent gas f'rom t h e pump

discharge as t h e system is being f i l l e d with salt.

A small flow of salt

w i l l r e t u r n t o t h e bowl through t h i s by-pass during normal operation. The "fountain flow" of about 15 gpm, which escapes f r a m t h e clearances between t h e impeller and t h e pump casing, etc., both pumps.

i s about t h e same i n

The coolant pump does not have t h e spray nozzles above

t h e s a l t l e v e l i n t h e pump bowl f o r t h e stripping of gases from t h e

288 pumped salt, as i s required f o r r e l e a s e o f fission-product gases i n t h e

f i e l - s a l t system.

A 1-1/2-in.

(See Section 5.4.1.2) v e r t i c a l nozzle i s provided a t t h e top of t h e pump bowl

f o r t h e taking of salt samples and f o r adding enriched material.

The

sampler-enricher system i s a simplified version o f t h e f u e l samplerenricher system. The salt l e v e l i n t h e pump bowl i s sensed by helium gas bubbler tubes i n t h e same manner as i n t h e f u e l pump, and a s described i n Section

10.9.1.

The short tube, l i n e 598, extends 1-5/8 i n . below t h e center-

l i n e of t h e pump volute, o r roughly 4-3/8 i n . below t h e normal operating l e v e l i n t h e bowl.

The long tube extends 4-1/16 i n . below t h e center-

l i n e of t h e volute and i s supplied with helium through l i n e 595.

The

reference pressure i s transmitted by l i n e 594 through a connection a t t h e top of t h e bowl.

used.

I n addition, a float-type l e v e l instrument i s

This instrument i s a s p e c i a l differential-transformer type de-

veloped a t ORNL, see P a r t 11. The e l e c t r i c a l s i g n a l i s transmitted t o both t h e d a t a logger and, a f t e r conversion t o a pneumatic signal, i s recorded on t h e same instrument as t h e l e v e l indication from t h e bubbler tubes. H e l i u m cover gas i s supplied through l i n e 512 and FCV-512 t o t h e pump shaft annulus j u s t below t h e lower s h a f t s e a l .

Off-gas i s with-

drawn fYom t h e top of t h e pump bowl through l i n e 328.

Line 526 with-

draws t h e oil-helium mixture leaking through t h e s e a l s t o prevent t h e migration of o i l vapor t o t h e coolant salt, i n t h e same manner as i n

t h e fie1 salt pump.. I

The pump bowl was fabricated with a 1-1/2-in. but t h e connection i s capped and not used.

overflow l i n e nozzle

Protection frorn"6verSLllLng i s

provided through use of l i q u i d l e v e l instrumentation. The coolant pump bowl does not have a shroud and a flow o f cooling

air around t h e upper portion.

The l e v e l o f a c t i v i t y i n t h e cover gas

i s so low t h a t cooling i s not required.

The pump d r i v e motor i s a 75-hp, Westinghouse, direct-connected type i d e n t i c a l t o t h a t used on t h e f u e l - s a l t pump except that t h e normal synchronous operating speed i s 1 7 3 rpm.

Operation a t d i f f e r e n t speeds

L/ %

289

.L4

can be obtained by varying t h e f'requency of t h e e l e c t r i c power supply through use of a motor-generator s e t which can be brought t o t h e MSRE

site.

The pump motor i s cooled by t r e a t e d water flowing through s t a i n -

l e s s s t e e l c o i l s h e l i a r c welded t o t h e motor can. l i s t e d i n Table 8.1. 8.3.2

The motor data a r e

( A l s o , see Section 5.4.1.3)

Hydraulics The hydraulic performance o f t h e coolant-salt pump w a s determined

on a water t e s t r i g f o r impeller diameters of 11.6, 10.82 and 9.9 i n . 49 Although t h e required design capacity of 8 9 gpm a t 78 t'f

of head could

be achieved with an impeller diameter of 9.9 in., a diameter of 10.33 i n . was specified i n order t o provide a margin f o r e r r o r of about 10%i n the system r e s i s t a n c e calculations and for a 3%v a r i a t i o n i n flow between t h e water t e s t pump and t h e MSRE operational u n i t .

A s shown i n t h e

c h a r a c t e r i s t i c curves i n Fig. 8.2, t h e coolant-salt pump has a capacity

of 8% t o 940 gpm under heads about 10%higher than t h e design value of

78 ft.130 8.3.3

Stresses The operating s t r e s s e s i n t h e coolant-salt pump a r e no l e s s severe

than i n t h e f u e l - s a l t pump, and i n some cases, required even c l o s e r a t tention.

See Sections 5.4.3 and 5.4.4 and Ref. 88.

8.3.4 pump Supports The coolant-salt pump i s mounted i n a fixed p o s i t i o n i n t h e coolant cell.

The coolant-salt piping has s u f f i c i e n t f l e x i b i l i t y t o absorb t h e

thermal expansion with t h e pump and r a d i a t o r a c t i n g as anchor p o i n t s . The f l e x i b i l i t y of t h e piping system i s discussed i n Section 8.6.1. The pump i s bolted t o a 2-in.-thick support p l a t e (See ORNL Dwg.

D-CC-D-41216),

which i n t u r n i s bolted a t each end with eight 2/8-in.

b o l t s t o a 5-in. square box header beam 18 i n . long.

These two box

beams a r e welded t o a >-in. I-beam s t r u c t u r e which i s fastened with through b o l t s t o t h e concrete wall o f t h e coolant c e l l .

Isomode v i -

b r a t i o n absorber pads are used under t h e w a l l mounting p l a t e s . ORNL DWg

. E-CC-D-41515)

(See

290

110

ngure 8.2.

Performance Curves for Coolant-Salt p~rmp

291 8.3.5

Heaters

The coolant-salt pump bowl has 11.2 kw of e l e c t r i c a l heat applied i n t h e form of fourteen 6-in. x 8-in. x 5/8-in.-thick f l a t - p l a t e ceramic heater units of 800 w a t 230 v capacity each. (See OlwL Dwg E-MM-€3-40837). S i x of t h e heaters a r e equally spaced a t t h e bottom o f t h e pump bowl and eight a r e arranged v e r t i c a l l y around t h e sides, with t h e surface of t h e heater p l a t e averaging about 1/2 i n . f’rom t h e outside surface of t h e bowl. The heaters a r e connected i n p a r a l l e l and mounted i n brackets i n a 304 s t a i n l e s s s t e e l heater basket.

This basket i s hung by four hooks f’rom

t h e pump support s t r u c t u r e so that t h e hesrters and basket do not touch t h e pump bowl.

The hegter leads use fish-spine ceramic i n s u l a t i n g beads

0.260-in. OD x 0.124-in. I D x 0.260 i n . long. The e l e c t r i c power supply i s through heater control panel HCP-4 and

i s adjusted by a Type 1256 Powerstat from 0 t o 240 v .

(See Section

19.7 -4)

8.3 .6 Them1 Insulation The outside of t h e heater basket i s insulated with 4 . i n . of Carey-

temp high-temperature insulation applied i n a conventional manner. (See ORNL Dwg E-MM-B-40837).

8.4

Radiator

One o f t h e chief considerations i n design of t h e MSRE r a d i a t o r was

that it be protected f’rom freezing of t h e c o o l a n t . s a l t i n t h e tubes i n t h e event of sudden losa of rbactor power. 13’, 132 Other important design f a c t o r s were that t h e r a d i a t o r was:to be used i n conjunction with air-handling equipment already installed i n B l d g 7503 as p a r t o f t h e

ART program, that t h e heat d i s s i p a t i o n rate be adjustable from zero t o

10-Mw, and that t h e u n i t must be capable o f operatmg f o r long periods of time without d i r e & approach f o r inspection o r maintenance. ’5’ The s a l t should move downward through t h e r a d i a t o r as 3t i s cooled.

general, t h e above considerations were of greater importance than designing for high performance c h a r a c t e r i s t i c s .

292 ,

cl.

8.4.1 Description (Also,

A drawing of t h e r a d i a t o r and enclosure i s shown i n Fig. 2.5.

see ORNL Assembly Dwgs E-DD-A-40431 and E-DD-D-40470).

The r a d i a t o r de-

sign data a r e summarized i n Table 8.2 ,

-8.4-.Yh$lCpil. --

- The r a d i a t o r c o i l has 120 INOR-8tubes, 3/4 i n .

OD, with O..O72-in. w a l l thickness, and each about 30 ft long.*

The

tubes a r e arranged i n an S-shaped configuration, 12 tubes high and LO tubes deep i n t h e d i r e c t i o n of a i r flow, as shown i n Figs. 8.3 and 8.4. The tubes a r e spaced 1-1/2 i n . on centers, and t h e rows a r e 1-1/2 i n . apart, with t h e tubes staggered, a s shown i n Fig. 8.4. This arrange2 ment provides about 706 ft of e f f e c t i v e heat t r a n s f e r surface. Each v e r t i c a l row of tubes terminates i n a manifold.

The t e n mani-

folds a t each end o f t h e c o i l j o i n horizontal 9-in. OD i n l e t and o u t l e t headers, t o which t h e 5-in. coolant salt c i r c u l a t i n g l i n e s a r e welded. The manifolds a r e 2-7/16-in. plate.

3;D and fabricated of 1/4-in.

(See ORNL Dwg E-DD-A-40744).

INOR-8

The p l a t e was first formed i n t o

a U-shape and then cold-drawn with a d i e t o form t h e nozzles f o r welding t h e 3/4-in. OD tubing t o t h e manifold.

The p l a t e was then formed

i n t o a c i r c u l a r cross section and t h e longitudinal seam weld and pipe cap were added t o cornplete t h e assembly.

The headers were constructed

i n e s s e n t i a l l y t h e same manner except t h a t t h e p l a t e thickness was 1/2 i n . The o u t l e t header is bolted t o t h e fixed r a d i a t o r s t r u c t u r e and i s an anchor point i n t h e coolant-salt piping system.

The i n l e t header

i s supported with s l o t t e d b o l t holes t h a t allow movement of t h e header due t o thermal expansion.

(See ORNL Dwg D-DD-A-40438).

The tubes a r e supported about every 4 ft by 3/4-in.-wide s t e e l s t r a p hangers, a s indicateq i n Fig. 8.5.

stainless

The tubing i s s u f f i -

c i e n t l y fYee within t h e hangers t o allow longitudinal movement.

Align-

ment pins passing through t h e s t r a p s maintain t h e row-to-row spacing. *tESrtended surface tubing usually associated with air-cooled c o i l s i s not used i n t h e E R E r a d i a t o r because less rapid heat t r a n s f e r i s des i r a b l e on sudden l o s s o f reactor power t o prevent freezing of t h e coolant s a l t i n t h e tubes.

" I

293

Unclassified ORNL IMG 64-8826

5" SCHD. 40, LINE 2 0 1

OUTLET :R

5" SCHD. 40, LINE 202

Fig. 8.3. Radiator C o i l Configuration

294

Unclassified ORNL LR DWG 54696R

1314

10 ROWS OF TUBES

CLEARANCE

L-1-1,*A-,-1/2-l

A I R FLOW

Fig. 8.4. Radiator Tube Matrix.

4 O.D. x 0.072" WALL

295 Unclassified ENCLOSURE FRAME

J 'mJ

ORNL DWG 64-8827

OR PIN

ANGLE

LENCLOSURE FRAME r

b, ,, 1

Fig. 8.5. R a d i a t o r T u b e Supports.

296 Table 8.2

Radiator Design Data

IN OR-^

Construction material

Temperature d i f f e r e n t i a l s 0

I n l e t 1100; Outlet 1023

I n l e t 100; Outlet 300

Salt, Air,

A i r flow, cfm @ 9.9 i n . ,

200,000

H2°

S a l t flow (at average temperature), gpm Effective mean AT,

862

Over-all c o e f f i c i e n t of heat t r a n s f e r , Btu/ f% -hr - O F Heat t r a n s f e r surface area, Design temperature,

830

93.5 706

Max. allowable i n t e r n a l pressure @ 12w0F, p s i

Operating pressure @ design point, p s i

Tube diameter, i n .

0.7%

Wall thickness, i n .

o .072

Tube length, f’t

Tube matrix

12 tubes per row; 10 rows deep

Tube spacing, i n .

142

Row spacing, i n .

1 4 2

Subheaders, in., IPS, sched-40

2 4 2

Main headers, i n . , ID (1/2 i n . w a l l )

A i r side, AP, i n . ,

9.9

S a l t side, AP, p s i

H2°

19.8

297

Ij Each of the radiator tubes i s provided with a thermocouple t o provide warning of restricted coolant-salt flow i n any of the passages. A t o t a l of 149 couples are installed i n the radiator, 120 on the tubes and the remainder on the i n l e t and butlet headers and tube supports. (See ORNL Dwg D-AA-B-40511). The insulation used for the thermocouples on the tubes is .Fibwfrax Ceramic Fiber, Grade gO-F, manufactured for the Carborundum Company (Viagara Falls, New York) by the Harlbut Paper Comgany. Although t e s t s indicated that the small amounts of sulphur, aluminum and lead i n the insulation caused no significant attack on INOR-8 a t elevated temperature^,'^^ the insulation having been baked a t 1600°F for four hours t o remove volatiles prior t o installation.

The radiator enclosure sup8.4.1.2 Enclosure and Insulation. ports the c o i l and provides a heated and an insulated jacket around it during the periods when it i s desirable t o maintain the heat within the c o i l . The c o i l supports i n the high-temperature regions consist of an inner 304 stainless s t e e l f’rame made of l/k-in,-thick built-up and formed structural shapes. This i s covered with 16-gage stainless s t e e l sheets. The stainless s t e e l frame i s bolted t o a carbon steel exterior structure, composed chiefly of 6-in., 12.5-lb I-beams anchored t o the coolant c e l l structural s t e e l framework. Slotteg bolt holes allow for differential thermal expansion Johns-Manville 1/2-in. -thick Marimite-23 insulation board i s used between the stainless and carbon s t e e l sections a t points of contact t o reduce t h e heat transfer t o t h e l a t t e r . (See ORNL Dwg E-DD-D-40472) The remainder of t h e carbon s t e e l framework i s protected from high temperature by Eagle-Picher Supper-Temp block insulation up t o 6 i n . thick. (See ORNL Dwgs E-DD-D-40470 and 40471) The portioas of t h i s insulation with surfaces which would have been swept by t h e a i r stream have protective covers of 16.-gage 304 stainless s t e e l . (See ORNL E-DD-D-40470) Flow of a i r , estimated t o be about 30,000 cfm a t the 10-Mw design power condition, by-passes beneath the c o i l t o cool the radiator support structure. The radiator doors do not cover these by-pass openings. I

8.4.1.3

Doors and Door Mechanism. The upstream and downstream faces o f the radiator enclosure are equipped with insulated doors t h a t 1

298

can move downward i n v e r t i c a l t r a c k s t o provide a f a i r l y a i r - t i g h t seal t o completely contain t h e r a d i a t o r c o i l i n an insulated and e l e c t r i c a l l y -

heated enclosure during t h e periods when it i s required t o conserve t h e heat i n t h e coolant salt system.

The doors a r e 8 ft high x 11 f t wide,

and each weighs about 1,770 l b s .

(See ORNL Dwg D-DD-B-40440)

Each door moves on cam r o l l e r s i n a U-shaped track, and as it reaches a nearly-closed position, r a i s e d areas on t h e t r a c k s force t h e door toward

t h e r a d i a t o r enclosure, compressing a braided Inconel-wire, asbestospacked gasket, mounted on t h e door periphery, against a sheet-metal spring

s e a l mounted on t h e r a d i a t o r enclosure.

(See ORNL Dwgs D-DD-B-40445,

40446, 40447 and 40449) The door frame i s made o f &-in. x O.l20-in.-thick

square carbon

s t e e l tubing, reinforced i n t e r n a l l y with v e r t i c a l carbon s t e e l T-sections L

and angle-cross braces.

(See ORNL Dwgs D-DD-B-40441,

40442 and 40443)

Door i n s u l a t i o n i s b i n . t h i c k Careytemp block covered with overlapping sheets of l/l6-in.-thick radiator c o i l .

s t a i n l e s s s t e e l on t h e s i d e facing t h e

The e x t e r i o r i s covered with 10-gage carbon s t e e l p l a t e .

(See ORNL Dwg D-DD-B-40444) The doors a r e r a i s e d and lowered a t a r a t e o f 10 f't/min by a 3-hp,*

3,150 f t - l b , 5-rpm output, U. S. E l e c t r i c Motors, Inc., Model 29U-50, gear motor mounted above t h e r a d i a t o r enclosure, a s shown i n Fig. 2.5. The motor i s connected t o t h e drive shafts f o r t h e individual doors by a chain drive.

(See ORNL Dwgs D-DD-C-40450,

40451, 40452 and 40468)

Each door i s equipped with a Fawick Corporation Model SC-1150 s t a t i o n a r y f i e l d type magnetic clutch and a Stearns E l e c t r i c Company S t y l e EB Size 1004, 48-volt DC, magnetic brake, which permit t h e doors t o be positioned independently of each o t h e r .

Clutch and brake torques

a r e 2,700 f t - l b s and 800 f t - l b s , respectively. Each door i s suspended from i t s d r i v e shaft by means of four 3/8-in. diam s t a i n l e s s s t e e l w i r e ropes attached t o two 8-in. -diam sheaves. (See ORNL Dwg D-DD-C-404%)

The wire ropes have a breaking strength of

*The t h e o r e t i c a l horsepower required t o r a i s e t h e door i s only s l i g h t l y more than 1 hp, but t h e motor was oversized t o provide t h e 'break away" torque needed t o overcome t h e f r i c t i o n i n t h e door gasket seal.

299

12,000 l b s .

The four ropes a r e connected i n p a i r s through two shock-

absorbing springs mounted on t h e top edge of each door. wheel, 39-1/2-in.

diam x 6-1/2-in.

A 2,3lO-lb f y -

wide, made of laminated s t e e l p l a t e s ,

i s attached t o one end of each of t h e door d r i v e shaf'ts through a Form-

(See O W L Dwg E-DD-C-40469)

sprag Model FS-7OO/2.75 over-running clutch.

The i n e r t i a of t h e flywheels l i m i t t h e speed a t which t h e doors would f a l l i n case of a loss of e l e c t r i c a l power, o r of a reactor scram.

The

time required f o r a door t o close i s estimated t o be about 3 seconds and t h e final v e l o c i t y of t h e door about 6 f t / s e c .

(See Ref 15, Section VII,

P 69)

8.4.1.4

Cooling A i r Blowers, Ducting and Dampers.

- A i r i s supplied

t o t h e r a d i a t o r by two 250-hp Joy Manufacturing Company "Axivane" blowers, Model AR600-36D-1225, Unit X-709-29 driven a t 1750 rpm by 250-hp General E l e c t r i c "Triclad", direct-connected,

induction motors, Model 36335-JY-1

Type M Frame 63352, 3-phase, 60-cycle, 44O-volts.

Each blower i s r a t e d

a t 82,500 cfm a t 15 i n . H20 o r 114,000 cfm with f r e e a i r delivery.

The

normal discharge pressure a t t h e reactor design power l e v e l of 10-Mw i s

9 i n . of H20, providing a combined capacity from t h e two blowers of about 200,900 cfm. The c h a r a c t e r i s t i c performance curve i s shown i n Fig. 8.9, and discussed i n Section 8.4.3. Each blower is provided with a fourbladed, motor-operated shut-off damper on t h e discharge which can be closed t o prevent backflow through t h e fans.

The blowers discharge i n t o

a 10 x l2-n air duct leading t o t h e plenum a t t h e face of t h e r a d i a t o r

coil. A by-pass duct beneath t h e r a d i a t o r contains a vertical-louvered

damper which can be adjusted t o control t h e flow through t h e by-pass and, therefore, t h e air passing over t h e r a d i a t o r c o i l . t o t h e by-pass duct i s 2 x 10 ft and about 5 f't duct a t an angle of about 6 0'

long, and leaves t h e main

with t h e horizontal.

contains t h e by-pass damper and i s 3 x 7 f 't

The entrance section

The center section

i n cross s e c t i o n a l area.

The

e x i t s e c t i o n i s i d e n t i c a l t o t h e entrance section.

A i r leaving t h e r a d i a t o r or t h e by-pass duct passes through turning vanes t o d i r e c t it up t h e 10-f't-diam x 75-ft-high free-standing s t e e l stack.

A p i t o t - v e n t u r i tube i s located near t h e top of t h e s t a c k t o

measure t h e a i r flow r a t e .

300

cri

The a i r ducts a r e fabricated of s t a i n l e s s s t e e l sheet.

These ducts

a r e contained within another duct t o form an annulus through which cool-

ing air\ i s passed t o cool t h e inside ducting t o prevent excessive warping and buckling.

The annulus air also p r o t e c t s any nearby concrete from

overheating a t low r e a c t o r power l e v e l s when t h e e x i t a i r *om a t o r c o i l may be as hot as l,OOO°F.

the radi-

A i r f o r t h e annulus i s supplied by

two 10-hp, l75O-rpm, Joy Manufacturing Company S e r i e s 1000 "Axivane" fans, Model 29-1/4-21-17w,

having a capacity o f 10,000 cf'm each a t 2 i n . H20 v

s t a t i c discharge pressure, as indicated i n t h e performance curves shown

in Fig. 8.6.

After cooling t h e annulus t h e a i r j o i n s t h e a i r from t h e

r a d i a t o r f o r discharge up t h e stack. 8.4.2

Stress The r a d i a t o r tubes were designed f o r a maximum i n t e r n a l pressure

of 3 ' 3 p s i g a t 1250'F.

The maximum combined thermal and mechanical

s t r e s s , which includes t h e e f f e c t of w i n d pressure, w a s found t o occur a t t h e outside circumference o f t h e tube and calculated t o be 3,224 p s i . (See Ref 15 Section VI1 p 46), A s indicated i n Table 2.2, t h e maximum allowable s t r e s s i n INOR-8 a t llOO°F i s 13,000 p s i and a t 1200°F i s 6,000 p s i .

Stresses i n t h e headers, tubes and piping due t o t h e i n t e r n a l

operating pressure of 75 p s i g w a s investigated and found t o be only about +

(See Ref 14 Section VI1 p 47) The r a d i a t o r w a s h y d r o s t a t i c a l l y t e s t e d a t 800 p s i and pnepnatically a t 670 p s i . 134

785 p s i .

Design s t u d i e s were made o f t h e s t r e s s e s i n tubing supports, headers, doors, and other members and found t o be well within allowable l i m i t s . (See Ref 15 Section V I 1 pp 48-59 and pp 60-69)

Shock loads on t h e s t r u c t u r e

when t h e r a d i a t o r doors a r e dropped was calculated t o be about 1,980 l b s

The wind load on the closed upstream door produces a maximum stress of

8,550 p s i i n t h e carbon steel T-sections when t h e pressure difference across t h e door i s 13 i n . H20. 8.4.3

Performance A t 10-Mw r e a c t o r power l e v e l t h e coolant..salt enters t h e r a d i a t o r

a t 11OO0F; a t zero power t h e entering temperature i s 1200°F

- l225'F.

The coolant-salt temperature leaving 1 t h e r a d i a t o r i s about 1025'F a t 10-Mw and i s 120OOF t o 1225'F a t zero power.

b, b

301

Unclassified ORNL DWG 64-8828

B 8

VoTume Figure 8 . 6 .

15 cfln in thousands

C h a r a c t e r i s t i c s of Radiator Duct Annulus Fans

k 4 m

302 A t t h e maximum load conditions t h e e f f e c t i v e log mean temperature difference i s 862OF, t h e s a l t film c o e f f i c i e n t i s about 3,420 Btu/hrt h e a i r f i l m coefficient i s about 61 Btu/hr-ft2-OF,

f't2-'F,

a l l heat t r a n s f e r coefficient i s about 9 Btu/hr-ft

p a r t V I 1 pp 8-25)

and t h e over-

2 0

- F.

(See R e f 15 2 The e f f e c t i v e heat t r a n s f e r surface of 706 f't thus

provides a calculated capacity of 10.4 MW. Inasmuch as the a i r f i l m r e s i s t a n c e i s about 95% of t h e t o t a l r e s i s t a n c e t o heat t r a n s f e r , t h e o v e r a l l c o e f f i c i e n t i s strongly influenced by t h e a i r v e l o c i t y over t h e tubes.

A t p a r t i a l loadings of t h e reactor,

t h e a i r flow w i l l be regulated by t h e by-pass damper, by changing t h e r a d i a t o r door position, and by on-off control o f t h e blowers.

The pres-

sure drop due t o t h e flow of air through t h e r a d i a t o r c o i l s i s a function o f t h e flow r a t e and t h i s , i n turn, e f f e c t s t h e s t a t i c pressure a t t h e blower o u t l e t s and t h e blower capacity.

The i n t e r p l a y of these several

variables on t h e a i r temperature leaving t h e r a d i a t o r under various loading conditions i s summarized i n Fig. 8.7,135 assuming s t e p l e s s c o n t r o l of t h e a i r flow over t h e c o i l .

If t h e cooling a i r e n t e r s t h e c o i l a t

1OO0F, a t t h e 10 Mw design power condition, t h e leaving a i r temperature i s about 300°F.

A t lower power l e v e l s t h e e x i t a i r temperature i s higher,

being about 4 y 0 F a t 4 Mw.

Below t h i s power l e v e l t h e e x i t a i r temperature

increases sharply, and i s estimated t o be about 800°F a t 1 Mw and 1000° t o llOO°F a t power l e v e l s below 0.5 Mw when t h e a i r flow r a t e s a r e r e l a t i v e l y small.

There a r e many possible combinations of mode of blower operation and r a d i a t o r door and by-pass damper positions which w i l l hold t h e r e a c t o r power a t a given l e v e l .

8.3. 136

One s e t of combinations i s summarized i n Table

The e f f e c t of t h e various step-wise adjustments on t h e a i r flow

was estimated, a s i l l u s t r a t e d i n Fig. 8.8. '35

There i s some d i s p a r i t y

between values i n these two studies but t h i s i s not of concern because experimentation with t h e a c t u a l system i s necessary t o e s t a b l i s h t h e best procedures.

Preliminary t e s t i n g of t h e blowers, r a d i a t o r doors and by-

pass dampers has indicated t h a t t h e s t a t i c pressure losses i n t h e system may be s u b s t a n t i a l l y l e s s than t h e estimates used i n t h e studies, demonstrating f u r t h e r t h a t t h e b e s t combinations f o r s t a b l e operation,

c k

, ,*

c Unclassified ORN-LDWGG-8829

Fraction Figure

8.7.

Radiator

Reactor

Air Flow Characteristics

Design Power

Unclassified

ORNL DWG 64-8830

- _

One Fan Running

TwoFans Running

240 Total Fan output

200

T o t a l Fan Output

Reactor Power Lwel Figure 8.8.

- Mw

Radiator Air Flow Characteristics at Vaxious Steps i n Load Regulation.

305

p a r t i c u l a r l y a t r e a c t o r power l e v e l s below 1 Mw, w i l l have t o be determined i n t h e f i e l d .

Studies were a l s o made of t h e operating sequences f o r r a p i d l y changing t h e r e a c t o r power from low t o high l e v e l s while maintaining t h e s t a b i l i t y o f t h e system and t h e required condition of constant f i e 1 s a l t temperature leaving t h e reactor.*

I n these s t u d i e s t h e system was s i m -

ulated by an analog computer. 137 Load changes a r e made manually using a single, spring-return type load demand switch t o increase o r decrease t h e power. The switch actuates

t h e programed control f o r t h e r a d i a t o r doors, blowers and by-pass damper, e s s e n t i a l l y as outlined i n Table 8.3.

In increasing t h e r e a c t o r loading

from, say, 1 M w t o 10 Mw, t h e i n i t i a l condition w i l l be with t h e r a d i a t o r doors about 35% open and t h e by-pass damper f u l l y open and one blower L

i n operation.

Manipulation of t h e load demand switch first causes t h e

r a d i a t o r doors t o be opened t o t h e i r l i m i t .

A f'urther increase i n load

i s obtained by closing t h e by-pass damper.

A s t i l l greater load demand

s t a r t s t h e second blower and a t t h e same time opens t h e by-pass damper These procedures w i l l be reviewed during t h e preliminary t e s t i n g

again.

of t h e r e a c t o r system. The c h a r a c t e r i s t i c s o f t h e a x i a l blowers supplying t h e cooling a i r a r e as indicated i n Fig. 8.9.

P a r a l l e l operation of t h e two blowers

under c e r t a i n loading conditions can lead t o unstable conditions with possible surging o f t h e load d i s t r i b u t i o n between t h e two blower driving motors.

A s indicated i n Fig. 8.9 t h i s i s most l i k e l y t o OCCUT a t about

100,000 cfm a i r d e l i v e r y and would tend t o be avoided by using one blower c

a t 100% of capacity r a t h e r than two a t reduced capacity. ing c h a r a c t e r i s t i c s must be determined *om

General operat-

t h e a c t u a l system.

Analog computer s t u d i e s were made t o determine t h e freezing time f o r stagnant salt i n t h e center of a r a d i a t o r tube.

Under design con-

d i t i o n s , with t h e maximum a i r flow, t h e estimated time was about 50 seconds. 138

b, a

*In t h e " s t a r t i n g mode" of operation a t r e a c t o r power l e v e l s below 1 Mw, t h e nuclear power i s held constant. I n t h e "run mode", a t power l e v e l s above 1 Mw, t h e f u e l - s a l t temperature leaving t h e r e a c t o r i s held constant.

306

Unclassified

ORNL DWG 64-8831

Model: AR600-360DW Air Density: 0.0697 lbs/ft3 Discharge Duct: 4.5 x 5 f't Blade Setting: 4-1/2 Joy Manuf'acturing Ccaqpaqy

I J

' I

p,/

Static Pressure

Recmended System Resistance L i m i t for Parallel Operation

Estimated Static Pressure Perfonaance of a Single Fan

600

400

I \ I

t m

2004

dki 0

80 Volume Flaw

Figure 8.9.

1x)

160

- c b i n thousands

200

Estimated Performance Both Radiator Supply Air Fans Operating i n P a r a l l e l .

240

307 Table 8.3

Step

Possible Steps for Controlling Heat Removal Rate from the Radiata$

Heat Removal Rate, Mw

0.03 (Heat leak)

Conditions Both radiator doors closed, bypass

damper open, fans o f f . 0.13

Upstream radiator door closed, downstream radiator door open, bypass damper open, fans off.

2.3

Both radiator doors open, bypass damper open, fans off.

3 *o

Both radiator doors open, bypass damper closed, fans o f f .

3 98

Both radiator doors open, bypass damper open, one fan on.

6.5

Both radiator doors open, bypass

damper closed, one fan on.

6.1

Both radiator doors open, bypass

damper open, two fans on.

10 .o

Both radiator doors open, bypass

damper closed, two fans on.

.*.

*From Ref 136 p 1

8.4.4

Heaters About 223 kw of e l e c t r i c heater capacity i s provided inside t h e

r a d i a t o r enclosure.

These heaters are used t o preheat t h e system before

t h e coolant.-salt i s added and t o maintain t h e temperature above 850OF a t

a l l times t h a t t h e salt i s i n t h e system. Tubular-type heaters a r e mounted 3-1/2 i n . a p a r t on t h e v e r t i c a l upstream and downstream faces of t h e c o i l .

These "Calrod" u n i t s a r e t r i -

angular i n cross section, about 0.33 i n . on a face, and a r e i n s t r a i g h t lengths.

There a r e twenty-four 48-in. lengths, e t h a capacity of

1,350 w each;

twelve 82-in. lengths of 2,500 w capacity each;

%-in. pieces having a capacity of 2,7% w each;

twelve

and twelve pieces 102

i n . long with 3,150 w capacity i n each length; making a t o t a l of 133,200 w capacity i n tubular h e a t e r s .

The heaters a r e supported i n v e r t i c a l rows

o f s i x each i n 304 s t a i n l e s s s t e e l clamps.

The heaters use 230 v, 3-phase

delta-connected e l e c t r i c power supplied through induction regulators CR1, CR4, CR5 and CR6 (See ORNL Dwg E-MM-B-40802 and Section 19.7 of t h i s

report )

F l a t ceramic-type h e a t e r s a r e used i n t h e horizontal p o s i t i o n s on t h e b a f f l e p l a t e s above and below t h e tube bundle. i d e n t i c a l 7-1/2-in.

The 60 heaters a r e

x 18-in. f l a t p l a t e s with a capacity of 1,000 w each.

The 208-v power i s supplied through induction regulators CR2 and CR3. The i n l e t header i s i n an insulated enclosure provided with f i f t e e n 4-in. x 12-in. f l a t ceramic heater p l a t e s of 1,000 w capacity each. a r e served by induction regulator CR7 and a r e r a t e d a t 230 v o l t s .

These (See

ORNL Dwg E-MM-B-40808)

The o u t l e t header enclosure i s equipped with twenty-seven &-in. x 12-in. p l a t e s of 550 w capacity each a t 230 v o l t s .

CR8 supplies these heaters.

Induction regulator

(See ORNL Dwg E-MM-B-40809)

A l l t h e ceramic-

type heaters are mounted i n 20-gage 304 s t a i n l e s s s t e e l cans held i n place by 16-gage c l i p s .

The ceramic heaters t o t a l 90 kw of capacity.

The nichrome heater wire leads a r e h e l i a r c welded t o extension leads

of No. 1 2 a l l o y 99 s o f t temper n i c k e l wire covered with 0.330-in. OD x 0 .l24-in. I D x 0.330-in. -long ceramic fish-spine beads.

309

8.3 C e l l Wall Penetrations f o r Lines 200 and 201 The coolant-salt l i n e s 200 and 201pass through t h e reactor c e l l

w a l l through s p e c i a l penetration assemblies which contain e l e c t r i c heat

e r s , thermal insulation, r a d i a t i o n shielding f o r t h e annulus between t h e process pipe and t h e penetration sleeve, and a r i g i d support t o serve as an anchor point for t h e piping. The penetrations f o r each pipe a r e e s s e n t i a l l y i d e n t i c a l .

The fol-

lowing description of a penetration would apply t o e i t h e r .

8.5.1 Reactor C e l l Sleeve

The 5-in. coolant-salt pipe passes through an anchor sleeve which i s mounted inside a r e a c t o r c e l l sleeve joining t h e reactor c e l l v e s s e l and

t h e outer s h e l l , o r tank.

(The space between t h e vessel and t h e s h e l l i s

f i l l e d with a magnetite sand-water mixture, as described i n Section 4.3 .l.)

A 24-in. sched 80 carbon s t e e l pipe, averaging about 16 i n . long, i s welded t o t h e k-in.-thick portion of t h e reactor c e l l vessel a t t h e l o cation shown i n Table 4.1.

A 32-in. OD x 0.625-in. w a l l thickness pipe,

averaging about 25 i n . long, i s welded t o t h e outside 3/8-in.-thick wall, which a l s o has 3/8-in. -thick s t i f f e n e r s a t t h i s p o i n t . '

tank

An ex-

pansion j o i n t , about 30 i n . OD x 26 i n . long, (Badger Manufacturing Company Model 24-6W7 Series 5 0 ) connects t h e 24-in, and 32-in. pipes t o make a l e a k - t i g h t j o i n t and accommodates 3/8 i n . l a t e r a l movement and

i -

1/4 i n . a x i a l movement between t h e inner and outer vessels.

(See ORNL

Dwg D-KK-D-407J-l and 40712) 8.5.2

Anchor Sleeve The coolant-salt l i n e s 200 and 201 a r e each anchored on t h e reactor

c e l l end of each penetration.

These anchors a r e designed t o withstand

t h e forces due t o t h e thermal expansions i n t h e primary and secondary systems. A 20-in. sched 80 carbon s t e e l pipe about 3 f% long f i t s i n s i d e the

reactor cell sleeve, described above.

hd b

The reactor c e l l end of t h i s pipe has a welded cap through which t h e 5-ic. NPS salt l i n e passes. !The pipe i s welded t o t h e cap by using a s p e c i a l 3-in.-long section welded i n t o

310

cli t h e process l i n e , t h i s section containing a shoulder which permits a full penetration weld that can be inspected and s t r e s s r e l i e v e d . t h e anchor point i n each l i n e .

This j o i n t i s

The coolant-cell end of t h e 20-in. pipe

anchor sleeve i s welded t o t h e 32-in. OD r e a c t o r c e l l sleeve described above.

See ORNL Dwg E-GG-C-41855

8.5.3

Shielding The annular space between t h e 5-in. process l i n e and t h e 20-in. anchor

sleeve i s e s s e n t i a l l y f i l l e d with 1-in.-thick 304 s t a i n l e s s s t e e l s h i e l d ing d i s c s f o r a distance of 8 i n . on t h e r e a c t o r c e l l end of t h e penetration.

The annual space between t h e heater s h e l l , t o be described below,

and t h e anchor sleeve has 1-in.-thick firebox s t e e l shielding d i s c s for

a distance of 12 i n .

The f i r s t eight d i s c s a r e s t a i n l e s s s t e e l because

they w i l l operate a t a higher temperature than t h e remaining twelve.

The

d i s c s a r e thermally insulated from t h e process pipe with a t h i n l a y e r of Fiberfrax bulk ceramic f i b e r i n s u l a t i o n (described i n Section 5.6.6.3). Other voids inside t h e anchor sleeve a r e a l s o f i l l e d with t h i s i n s u l a t ing material.

8.5.4

See ORNL Dwg E-GG-Z-55498.

Heaters and Insulation With t h e exception o f about 12 i n . on t h e r e a c t o r c e l l end of t h e

penetration, t h e process pipe i n s i d e t h e anchor sleeve i s surrounded by e l e c t r i c heating elements contained i n a s t a i n l e s s s t e e l s h e l l .

The

heaters a r e removable from the coolant-cell end of t h e penetration, although probably with some d i f f i c u l t y because of t h e r a d i a t i o n streaming through t h e opening.

Four l/k-cylinder ceramic heating elements ( f o r d e s c r i p t i o n see section 5.6.6.2) = . i n .

long, each with a capacity of 3,000 watts

(at 230 v ) provide t h e r e l a t i v e l y l a r g e amount of heat needed on t h e r e a c t o r - c e l l end of t h e penetration t o keep t h e unheated length up t o temperature and t o compensate f o r t h e heat conducted from t h e pipe w a l l a t t h e anchor p o i n t .

On t h e coolant-cell s i d e of t h i s heater section

a r e four 12-in. long heater sections, each containing four l/k-cylinder heating elements of 300 watts capacity each (at 230 v ) .

Only one-half

of each o f t h e heater sections i s used a t one time, t h e other portion Gerving as a spare.

311 With t h e exception of t h e l a s t heater section on t h e coolant-cell end, t h e heaters a r e contained i n a 22-gage, 304 stainless s t e e l s h e l l , about 10 i n . diam x 4 ft long.

This s h e l l is provided with spacers and

lugs t o hold t h e ceramic heating p l a t e s , t h e heater leads, and t h e thermocouple sheaths, i n position. insulated with a 3-l/2-in.

The outside of t h e heater s h e l l i s thermally

thickness of Careytemp 1600 expanded s i l i c a

insulation, as described i n Section 5.6.6.3. See ORNL Dwg E-MM-Z-51670 for general assembly of heaters and i n sulation.

8.6

Secondary Circulating System Piping and Supports

The tube s i d e of t h e primary heat exchanger, t h e coolant-salt pump and t h e r a d i a t o r a r e interconnected w i t h 5-in. sched 40 INOR-8piping. With t h e exceptions of t h e portions of t h e l i n e s 200 and 201 inside t h e reactor c e l l , a l l t h e coolant-salt piping i s accessible for maintenance a short time after reactor shutdown and uses more o r l e s s conventional welded pipe j o i n t s and methods of heating, i n s u l a t i n g and supporting t h e piping. Long radius (23-in.) bends a r e used where possible. The piping a t the reactor c e l l wall penetrations, a t t h e pump and a t t h e r a d i a t o r nozzles, i s fixed i n position, t h e thermal expansion being accommodated by t h e f l e x i b i l i t y of t h e piping. A l l horizontal runs of piping in the circulating and d r a i n systems

p i t c h downward a t about 3

. The c i r c d a t i n g system pitches t o two low

points, one i n l i n e 201 Just outside the r e a c t o r c e l l w a l l penetration, and t h e other i n l i n e 202 a t t h e bottom o u t l e t of t h e r a d i a t o r . two 1-1/2-in.

The

sched 40 INOR-8drains, l i n e s 204 and 206, a r e connected

a t these points. The freeze flanges, freeze valves, pipe l i n e heaters and thermal i n s u l a t i o n f o r t h e coolant-salt pi2ing a r e described and included i n t h e tabulations of t h e corresponding equipment i n t h e primary c i r c u l a t ing system, Section 5.6, i n order t o complete each of those p a r t i c u l a r sections of t h e r e p o r t .

Ir J

312

61 8 & .1 Piping Stresses and F l e x i b i l i t y Analyses

The coolant-salt piping inside t h e reactor c e l l , l i n e s 200 and 201, a r e s u f f i c i e n t l y f l e x i b l e between t h e anchor point a t t h e c e l l w a l l and t h e heat exchanger nozzles t o absorb t h e thermal expansion of 'the piping and t h e movements of t h e heat exchanger.

The s t r e s s e s i n t h e coolant-

salt piping were included i n t h e f l e x i b i l i t y analyses made of t h e primary

piping, see Section 5.6.2.

It i s t o be noted t h a t t h e maximum stress i n

t h e reactor c e l l s a l t piping was determined t o be about 7,700 p s i a t t h e coolant-salt i n l e t nozzle t o t h e heat exchanger. 105 1

The coolant-salt piping outside t h e reactor c e l l i s anchored a t t h e c e l l w a l l penetration and a t t h e r a d i a t o r and pump nozzles. E-GG-B-40702. are:

See ORNL Dwg

The major pieces of piping, a l l of which a r e 5-in. NPS,

l i n e 200 from t h e pump discharge t o t h e c e l l w a l l penetration,

l i n e 201 from t h e penetration t o t h e i n l e t header a t t h e top of t h e rad i a t o r bottom o u t l e t header t o t h e bottom o f t h e coolant pump bowl.

Line

202 contains a 25-in. radiuk r e t u r n bend f o r t h e necessary f l e x i b i l i t y , and it i s i n t h i s bend t h a t ' t h e maximum pipeline expansion s t r e s s of 12,818 p s i occurs. 139

This i s withic t h e allowable s t r e s s range of

32,125 p s i as determined by t h e Code of Pressure Piping, ASA B 3 l . l . (Also, see footnote, Section 5.6.2)

106

The expansion s t r e s s e s i n l i n e s 200

and 201, which a l s o contain 2>-in.-radium 180' r e t u r n bends, a r e 11,931 and 8,851 p s i , respectively. 139 The forces and moments a t t h e pump support p l a t e s and a t t h e rad i a t o r i n l e t and o u t l e t nozzles a r e within t h e acceptable values. 139 8.6.2

Coolant -Salt PiDine: SuDDorts The supports f o r coolant-salt l i n e s 200 and 201 inside t h e reactor

c e l l a r e l i s t e d i n Table 5.10 i n Section 5.6.2. The 5-in. coolant-salt piping i n t h e coolant c e l l i s hung on constant-load Bergen supports t o minimize s t r e s s e s during warmup of t h e system.

Each of these supports a preset load equal t o t h e calculated

weight of t h e piping and contents a t t h a t p a r t i c u l a r point, when t h e support spring i s i n t h e zero position.

A s t h e system i s heated, t h e

piping moves up o r down a t each position, a s shown i n Table 8.4.

This

313

W This movement i s less than t h e maximum permissible movement of t h e 2

hanger i n each case so t h a t no additional s t r e s s e s a r e imposed on t h e piping by t h e supports. Additional information on each hanger i s shown i n Table 8.4.

Table,8.4. ERE supPo rt No.

Line Number

ccs-1

200

ccs-2

Bergen Number & Typea

Preset badb

MaximumHanger Movement, i n ,

Near c e l l w a l l

CSH-5 C - 1

315

+1.25 -

200

Bottom of 180' v e r t i c a l bend

CSH-4 D-1

260

+1 - .o

+o .22 +o .25

ccs-3

200

Top of 180' v e r t i c a l bend

CSH-3 D-1

180

+1.5 -

-0.50

ccs-4 ccs-5 ccs -6

200

Below coolant pump

CSH-5 D-1

+2 - .o

-0.52

202

Near r a d i a t o r

CSH-4 B-1

295 210

+1.25 -

+o .31

202

Bottom of 180' v e r t i c a l bend

CSH-4 D - 1

200

+1.25

negl

ccs-7

202

Top o f 180' v e r t i c a l bend

CSH-4 D - 1

225

+2 - .o

-0.82

ccs -8 ccs-g ccs-10

202

Below coolant pump

CSH-4 B-1

225

+2 - .o

-0.52

201

Near c e l l wall

CSH-5 B-1

330

+1 - .o

negl

201

Bottom o f 1m0 v e r t i c a l bend

CSH-5 D - 1

335

+1 - .o

+o .44

ccs-11

201

Top of 180O v e r t i c a l bend

CSH-4 D-1

210

+i - .25

ccs-12

201

Near r a d i a t o r

CSH-2 D-1

135

+1 - .o

. negl .

a b c d

Coolant C e l l S a l t Piping Supports

Location

LbS

Maximum Calculated Pipe Movement on Heating, in.

. .

negl

Constant-load supports. Bergen Pipe Support Corporation (New York, N . Y . ) Preset load i s t h e expected load fl-om weight of pipe and contents. P o s i t i v e values a r e up and negative values downward. See ORNL m g E-GG-E-41866,

I I*

315

9. COOIANT-SALT STOR GE SYSW A storage tank i s provided a t t h e bottom of t h e coolant c e l l t o per-

m i t complete drainage of t h e coolant-salt c i r c u l a t i n g system.

The coolant

d r a i n system c o n s i s t s o f a d r a i n tank, various drain and t r a n s f e r l i n e s , freeze valves, and t h e associated valving, e l e c t r i c heaters, instrument a t i o n , thermal insulation, e t c

Since t h e coolant salt does not generate appreciable a f t e r h e a t when drained i n t o i t s storage tank, t h e heat removal system used on t h e f u e l

drain tanks i s not required on t h e coolant-salt d r a i n tanks.

In other

respects t h e tanks f o r t h e two systems are similar, see Fig. 2.6.

Much

of t h e equipment i n t h e coolant-salt d r a i n system i s of conventional design, since t h e coolant c e l l can be entered a short time after r e a c t o r shutdown f o r d i r e c t inspection and maintenance. A l l p a r t s of t h e system i n contact with t h e coolant salt a r e fabricated of INOR-8. The portable cans f o r t r a n s f e r of coolant s a l t t o and from t h e MSRE s i t e a r e described separately i n P a r t V I I .

9.1 Layout and General Description The coolant-salt d r a i n tank i s located a t t h e 8204% elevation below t h e r a d i a t o r and i t s ducting i n t h e coolant c e l l , as shown i n Figs. 4.4 and 4.5. (See ORNL Dwgs E-GG-D-41888 and E-W-B-40702)

Two d r a i n l i n e s a r e required t o completely empty t h e coolant-salt c i r c u l a t i n g system because o f t h e piping configuration r e s u l t i n g from t h e requirement t h a t t h e flow of coolant salt be downward through t h e

radiator. Q

Each of t h e s e 1-1/2-in.

sched 40 d r a i n l i n e s i s provided w i t h

freeze valve, which, on i n t e r r u p t i o n of t h e cooling a i r flow against

it, w i l l t h a w and cause t h e system t o d r a i n by g r a v i t y . During drainage t h e gas i n t h e drain tank can be t r a n s f e r r e d t o t h e t o p o f t h e c i r c u l a t ing system, o r it may be vented t o t h e off-gas system through a 1/2-in. pipe leading p a s t a r a d i a t i o n monitor and t o t h e absolute f i l t e r s and the stack. The 40-in.-diam x 78-in.-high d r a i n tank has a volume of about Yl ft’; t h e r e i s approximately 44 ft3 of coolant s a l t i n t h e c i r c u l a t i n g system.

316 The drained s a l t enters t h e top of t h e tank, and by means of an i n t e r n a l I

d i p tube, i s discharged a t t h e bottom.

This d i p tube permits t r a n s f e r of 5

s a l t back i n t o t h e c i r c u l a t i n g system by pressurization with helium gas introduced a t a top connection.

The tank i s provided with a single-point

l i q u i d l e v e l probe and with weigh c e l l s t o determine t h e tank inventory. The coolant s a l t i s brought t o t h e s i t e i n 2-1/2-f%' 250 t o 300 l b s of t h e non-uranium-bearing s a l t .

cans holding

The charging s t a t i o n ,

where t h e cans a r e heated and connected t o t h e system, i s a t t h e 852-ft elevation above t h e s p e c i a l equipment room. I

Removal of a s h i e l d block on

t h e southwest corner of t h e roof o f t h e room permits connection of a charging l i n e from t h e cans t o a permanently-installed 1 - i n . flange a t pipe leadt h e 84g-ft elevation, which i s t h e terminus of a 1/2-in. INOR-8 ing t o a flanged connection j u s t above t h e coolant s a l t d r a i n tank.

The

blank flange normally i n place a t t h i s l o w e r connection i s removed and t h e permanently-installed charging l i n e i s connected.

The charging l i n e dips

i n t e r n a l l y t o t h e bottom of t h e tank so t h a t s a l t can be t r a n s f e r r e d back t o t h e portable cans through t h e same l i n e s . 9.2

Flowsheet

The coolant-salt d r a i n system i s included on t h e flowsheet f o r t h e coolant system, Fig. 8.1 (ORNL Dwg E-~-A-40881). S a l t i s drained *om

t h e low point of t h e coolant-salt piping i n t h e

coolant c e l l j u s t outside t h e reactor c e l l w a l l penetration through t h e 1-1/2-in.

sched 40 l i n e 204.

The low point i n t h e piping a t t h e r a d i a t o r

o u t l e t i s a l s o drained through a 1-1/2-in.

pipe, l i n e 206.

The freeze

valves i n these two l i n e s , FV-204 and FV-206, have t h e i r e x i t s joined by a t e e with t h e branch o u t l e t facing upwards and connected t o a short,

v e r t i c a l length of b i n . sched 40 pipe with caps a t each end.

This r e s -

ervoir, which has an o v e r a l l height of about 7 i n . , i s t o assure a suff i c i e n t q u a n t i t y of s a l t i n t h e freeze valves a f t e r a d r a i n t o a f f e c t a good s e a l .

The pipe from t h e top of t h e k-in.-pipe r e s e r v o i r t o t h e top

of t h e drain tank, l i n e 204, i s 1 - i n . sched 40, t h e smaller s i z e being used t o obtain t h e f l e x i b i l i t y i n t h e tank connections needed for proper operation of t h e weigh c e l l s .

* I

317 One e l e c t r i c heater c i r c u i t and one thermocouple a r e provided between t h e d r a i n tank and t h e freeze valves.

Each of t h e two fYeeze

valves has t h r e e heater c i r c u i t s , one i n t h e center, one t o control t h e shoulder temperature a t both ends o f t h e valve and one on t h e freeze valve r e s e r v o i r .

There i s a thermocouple a t each section of t h e shoulder

heaters and t h r e e couples on t h e freeze valve i t s e l f . S a l t i s added t o t h e d r a i n tank through a 1/2-in. pipe, l i n e 203. This l i n e leads from a flanged j o i n t a t t h e top of t h e s p e c i a l equipment

. -

room t o a flanged connection a t t h e top of t h e d r a i n tank, and, by means of a d i p tube, t o within about 1-1/2 i n . o f t h e tank bottom.

has one heater c i r c u i t and eight thermocouples.

Line 203

When not i n use i n

adding o r removing s a l t f r o m t h e system, l i n e 203 i s blanked o f f both

a t t h e flange above t h e drain tank and a t t h e connection near t h e roof

Plug * When salt i s t o be added t o t h e system, a helium cylinder i s connected t o t h e 3/8 i n . tubing a t t h e charging s t a t i o n , l i n e 615.

This

l i n e contains a pressure regulator, PCV-619, and upstream and downstream pressure gages.

Line 615 then branches i n t o two i d e n t i c a l pressurizing

stations, or Wits.

In t h e following description of one of t h e s t a t i o n s ,

t h e l i n e numbers for t h e other a r e given i n parenthesis.

Line 615 con-

nects t o l i n e 611 (612) a t t h e pressure c o n t r o l valve PCV-611 (PCV-612).

Downstream o f t h e c o n t r o l valve and t h e pressure gage connection, t h e (

l i n e branches t o f l o w through t w o valves connected i n parallel,

( v - 6 1 2 - ~ ) and V-611.~ (v-612-~), one of which serves as a spare.

v - 6 1 ~ ~ Line

611 (612) continues p a s t a pressure gage connection and t o a removable 6.

spool piece, which i s used t o make t h e temporary connection t o t h e p o r t a b l e salt cans. Helium f o r p r e s s u r i z a t i o n of t h e drain t h e tank is supplied by t h e 1/2-in. pipe, nished a t 40 p s i g from t h e 1/2-in. l i n e Section 10.

A pressure regulator,

sure t o t h e tank t o 30 p s i g . valve HCV-5lU, downstream

s, c

of t r a n s f e r .

The t h r e e

t h r o t t l i n g and control

salt t r a n s f e r f’rom The helium is f’ursystem, see supply pres-

valve, CF-511, i s provided i n t h e helium supply t o prevent backflow i n t o t h e cover gas system.

The handvalves, V-5llA and V-?llB,

provide i s o -

l a t i o n of t h e gas supply valves f o r maintenance purposes. The coolant drain tank i s normally vented t o t h e off-gas system through a 1/2-in. s t a i n l e s s s t e e l pipe, l i n e 547, v i a l i n e 527.

The

l a t t e r i s connected t o t h e top of t h e tank a t t h e same nozzle as t h e Line 547 contains a pneumatically-

helium pressurization gas supply.

operated control valve, HCV-547, which i s adjusted by a hand switch a t t h e control panel. When draining salt flrom t h e c i r c u l a t i n g system, t h e s a l t i n t h e loop i s exchanged f o r t h e gas i n t h e d r a i n tank through t h e 1/2-in. connecting piping and valves, l i n e s 527, 536 and 528.

inter-

Line 527 contains

a c o n t r o l valve, HCV-527, before i t s juncture with l i n e 536 upstream of t h e control valve HCV-536.

Line 536 j o i n s l i n e 528 upstream o f t h e con-

t r o l valve, PCV-528. Line 528 connects t o t h e top of t h e pump bowl. This valving arrangement permits venting t h e gas from t h e top of t h e pump bowl through l i n e 528 and 536.

Line 536, and i t s valve, HCV-536,

bypasses t h e c o n t r o l valve ~ ~ ~ - 5 which 2 8 , i s s e t t o pass only about 1.4 liters/min of gas i n t o t h e system, and would thus have i n s u f f i c i e n t capacity when t h e flow i s i n t h e reverse d i r e c t i o n a s s a l t i s being added t o t h e c i r c u l a t i n g system.

A d e t a i l e d description of t h e f i l l i n g

procedures i s given i n P a r t V I I I .

9.3 9.3.1

Coolant-Salt Drain Tank

Tank The coolant-salt storage tank i s 40 i n . OD x about 78 i n . high,

overall, with a w a l l thickness of 3/8 i n . i n t h e c y l i n d r i c a l portion. The t o r i s p h e r i c a l ASME flanged and dished heads a r e 3/8 i n . t h i c k .

The

tank i s mounted v e r t i c a l l y on weigh c e l l s by a support system described subsequently i n Section 9.3.2. Other p e r t i n e n t d a t a a r e given i n Table

9.1. The tank and a l l i t s attachments a r e fabricated of INOR-8 and generally i n accordance with ORNL Specification MSR 62-3.

The tank w a s

g, 3

,-. -

319

LJ ?

designed for an i n t e r n a l pressure of 65 p s i g a t 13000F, and i n accordance with t h e requirements of Section VI11 of t h e ASME Unfired Pressure

Vessel Code47 for primary nuclear v e s s e l s .

The calculations of t h e

s t r e s s e s i n t h e walls, heads, and nozzles were based on standard relationships (See P a r t IV Ref 18) and a r e within t h e allowable s t r e s s of

16 f o r INOR-8.

3500 p s i a t 1300'F

The t o p head i s penetrated by f i v e nozzles, as l i s t e d i n Table 9.1. A 3-in. sched 40 pipe provides a n inspection p o r t and access f o r a s a l t 3

sampler.

This nozzle i s flanged w i t h a 3-in.,

l y - l b , r i n g - j o i n t , weld-

neck flange and a mating blind flange having a l e a k detector connection.

The 1 - i n . nozzle for t h e d r a i n connection, l i n e 204, e n t e r s t h e t o p

head a t t h e center and extends approximately 1-1/2 in. above t h e lower head.

A 1/2-in.

sched 40 pipe, l i n e 203, a l s o extends through the top

head and, by means of a bend i n t h e d i p tube, terminates a t t h e center of t h e lower head.

This arrangement i s designed t o reduce t h e amount

of "heel" l e f t i n t h e tank a f t e r a t r a n s f e r .

The two l i n e s a r e welded

together a t t h e bottom t o provide s t i f f e n i n g .

Line 203 has a s p e c i a l

flange j u s t above t h e tank, see Section 9.4, following.

A 1/2-in. sched 40 nozzle i n t h e top head i s used for gas p r e s -

s u r i z a t i o n and for venting.

A 2-1/2-in.

of t h e l e v e l probe, LE-CDT.

This instrument has two single-point con-

nozzle i s used f o r i n s e r t i o n

d u c t i v i t y type probes which i n d i c a t e s whether t h e salt i s above o r below points marking 5% and 9 %o f t h e s a l t storage volume.

(See I n s t r u -

mentation, P a r t 11)

9.3.2

Supports and Weigh Cells !!he coolant d r a i n tank i s supported by two b i n . NPS steel pipe

columns r e s t i n g on t h e coolant d r a i n c e l l floor a t t h e 820-ft elevation. (See ORNL Dwg E-W-D-41503 )

The i n s t a l l a t i o n incorporates two pneumatic

load c e l l s (A. H. a e r y Company) f o r determining t h e inventory of salt

i n t h e tank. A ll/l6-in.-thick

x 6-in.-wide

skirt i s joined with a full c i r -

cumferential weld t o t h e t o p of t h e tank just above t h e head weld, Twelve s t a i n l e s s s t e e l hanger rods, 5/8-in.-diam

x 8-1/2 i n . long, a r e

fastened by clevis-type couplings t o t h i s s k i r t and suspend t h e tank

320 Table 9.1 Design Data for Coolant-Salt Drain Tank

Construction material

INOR-8

Height, in.

Diameter, in. OD

Wall thicknesses, in. Vessel

318

Heads

5/8

Volume, ft3 Total

-50

Coolant -salt normal storage

-44

Design temperature,

Design pressure, psig

1300

Nozzles, NPS (sched 40), in. Inspection port and sampler

Salt drain line 204

Salt transfer line 203

112

Gas pressurization line 511

112

Level probe, LE-CDT

2-112

321

f'rom t h e support ring above. The carbon s t e e l support ring i s about 41-7/8-in. OD x 6 i n . deep, and i s fabricated of 1-1/2-in. plate*. It h?s. two arms about 20 in. long extending from opposite sides. Each of the arms i s suspended by three carbon s t e e l hanger bolts,= 3/8-in. OD ;. 38 i'n. long, f'rom a pneumatic load c e l l resting on a 3/4-in.-diam s t e e l b a l l mounted on top of the support column. The columns pass through holes i n the above-mentioned support ring w i t h a clearance o f 1/4 i n . on a diameter, an amount sufficient t o allow proper operation of the weigh cells, but a t the same time preventing the tank assembly from f a l l i n g off the supports. The long hanger rods and the point support

arrangement reduces the horizontal loading on t,he weigh c e l l s t o a negl i g i b l e amount. To effect maintenance on a weigh c e l l , o r prior t o removal of a

tank from the system, the weight of the tank must be removed from the weigh c e l l s . To accomplish t h i s , the ends of each support ring arms a r e equipped w i t h a jack bolt which operates against a bracket on the support columns, just below the arms. A slight l i f t i n g of the arms by these bolts permits unthreading of t h e three hanger bolts on each weigh c e l l . It may be desirable a t times t o remove t h e weight from the jack bolts, such as t o prevent swaying when cutting a pipe. To provide for t h i s a collar i s installed on each support column j u s t below the arms. The weight o f t h e assembly can be lowered onto these collars by backing off on the jack bolts a f t e r disconnecting the weigh c e l l hanger rods. Further description of the maintenance procedures i s given i n Part X.

9.3.3

Electric Heaters and Insulation

The coolant-salt drain tank i s heated on the sides by tubular heaters totaling 11 kw, and on t h e bottom by ceramic flat-plate heater units t o t a l i n g 6 kw. A l i k e amount of heater units are installed as and E-MM-A-408321 spare capacity. (See OFXL Dwgs ~-m-~-51668 There are thirty-two tubular heaters curved t o a 20-13/16-in. radius installed on the tank sides i n a 304L stainless steel fl-me. L

*AS'1M-A-285-57T Grade C f i r e box s t e e l . *ASTM-A-193 Grade B7 steel.

. 322 Each u n i t i s a Calrod h e a t e r 0.315 i n . OD x 74 i n . long, with a heated

cei c

length of 60 in., sheathed i n inconel, and r a t e d a t 2500 w a t 230 v . a

In each case two heaters a r e connected i n s e r i e s , and with a supply voltage of 244 v, t h e a c t u a l capacity o f each u n i t i s TOO w, or 140 w / f t . The tubular heaters are arranged i n 16 h o r i z o n t a l rows on 4-in. centers, with t h e two h e a t e r s p e r row connected i n s e r i e s .

The 16 rows

a r e divided i n t o two equal groups, one termed t h e "top" s e c t i o n and t h e other t h e "middle" section.

Every other row i s for normal use and t h e

remaining rows serve as spare units.

There a r e thus four rows of two

working heaters each i n each section, o r a t o t a l of 5.6 -/section, with t h e four rows connected i n p a r a l l e l . The spare heater leads a r e terminated i n junction box CS-1, located a t t h e 840-ft elevation.

(See

ORNL Dwgs ~ - m - z - 5 1 6 2 5 and ~-m-c-31667)

The sixteen heaters on t h e bottom of t h e d r a i n tank, and termed t h e "bottom" section, a r e f l a t ceramic heater p l a t e s about 7/8 i n . t h i c k and having a t r a p i z o d i a l shape roughly resembling a r i g h t t r i a n g l e with an a l t i t u d e of 14 i n . and a base of 7 i n .

(See ORNL Dwg E-MM-B-40829)

The h e a t e r s a r e r a t e d a t 7 3 w a t t s each a t 230 v o l t s .

H a l f o f the units

a r e used as spares, providing a t o t a l working capacity of 6 kw.

All

heaters a r e connected i n p a r a l l e l with t h e e l e c t r i c a l leads f o r t h e spare group terminating i n junction box CS-1 i n t h e basement regulator a r e a . The u n i t s a r e arranged r a d i a l l y i n a 304L S t a i n l e s s s t e e l support basket suspended from t h e bottom of t h e tank. The drain tank i s thermally insulated with two l a y e r s of 2-1/2-in.t h i c k "Careytemp" 1600°F block i n s u l a t i o n .

A 20-gage 304L s t a i n l e s s

s t e e l l i n e r i s used between t h e tubular heaters and t h e thermal insuThe insulation i s applied i n a conventional manner since t h e

lation.

u n i t can be approached f o r d i r e c t maintenance.

9.3.4

Thermocouples The temperature of t h e d r a i n tank i s monitored by t h i r t e e n thermo-

couples.

Two of these a r e located a t t h e center of t h e bottom, two a t

t h e charging l i n e nozzle, two a t t h e d r a i n l i n e nozzle, and t h e r e s t a r e d i s t r i b u t e d over t h e tank w a l l , as shown on ORNL Dwg D-HH-B-40532. One thermocouple on t h e bottom head, two on t h e top head (one from each

323

, u

l o c a t i o n ) and one on t h e w a l l near t h e bottom, a r e connected t o t h e d a t a logger.

One thermocouple from t h e wall near t h e midplane i s recorded

and t h e remaining eight couples a r e scanned and displayed.

9.4 Coolant-Salt Transfer Line 203 This l i n e i s used t o t r a n s f e r s a l t from t h e portable cans t o t h e

drain tank when adding s a l t t o t h e system and f o r returning t h e s a l t s t o t h e cans when reprocessing i s required.

The l i n e c o n s i s t s of a 3/8-in.

OD x 0.035-in. w a l l thickness monel (or inconel) tubing p o r t i o n which i s i n s t a l l e d only when making t r a n s f e r operations.

The tubing leads from

t h e portable cans t o a s p e c i a l flange a t t h e 849-ft elevation a t t h e southwest corner o f t h e s p e c i a l equipment room.

From t h i s flange a per-

manently i n s t a l l e d 1/2-in. sched 40 IN OR-^ pipe leads t o another s p e c i a l flange located j u s t above t h e top of t h e coolant-salt d r a i n tank.

9.4.1 Upper Flange on Line 203 The 3/8-in. OD tubing from t h e portable cans i s connected t o a 1/2-in. s t a i n l e s s s t e e l , r i n g - j o i n t flange.

(See ORNL Dwg E - G G - D - 5 9 1 2 )

The

tubing i s i n s e r t e d 8 i n . through t h e center of t h e flange using compression f i t t i n g s .

This flange mates w i t h a s t a i n l e s s s t e e l flange having

t h e basic dimensions of a 1 - i n . 150-lb r i n g - j o i n t , weld-neck flange, but

is machined t o a t t a c h a 1/2-in. sched 40 INOR-8 pipe. x

1 %

1 - i n . flange i s provided with a 1/4-in. OD tubing connection through which helium purge gas can be introduced.

The s i d e of t h e

This arrangement i s used t o

purge t h e l i n e of a i r before t h e s a l t t r a n s f e r i s made and a l s o assures

a gas space i n t h e annulus between t h e tubing and t h e pipe w a l l t o prevent t h e coolant salt from coming i n contact with t h e s t a i n l e s s s t e e l flange.

When Line 203 i s not i n use, t h e tubing t o t h e portable cans i s disconnected and a s t a i n l e s s s t e e l blank flange i s used t o close t h e upper flange opening t o prevent contaminants from entering. 9.4.2

b w e r Flange on Line 203 The 1/2-in0 INOR-8 pipe leading from t h e upper flange terminates i n

324 a 1/2-in. INOR-8r i n g - j o i n t , weld-neck flange j u s t above t h e d r a i n tank

nozzle.

A 3/8-in. OD x O.035-in. w a l l thickness x 12-in. long piece of

monel (or inconel) tubing i s welded t o t h e bottom center opening t o extend t h e l i n e i n t o t h e d r a i n tank nozzle.

(See ORNL Dwg E-FF-A-40433)

The mating flange on t h e d r a i n tank nozzle i s a 1 - i n . INOR-8r i n g - j o i n t , weld-neck flange bored t o accommodate t h e 1/2-in. sched 40 d r a i n tank nozzle.

The s i d e of t h i s flange i s provided with 1/4-in. OD tubing

connections leading t o t h e helium gas supply i n t h e leak-detector system.

A s i n t h e upper flange, t h i s arrangement i s designed t o form an annulus i n which t h e helium gas prevents t h e s a l t from contacting t h e gasketed j o i n t , where exceptional cleanliness i s required when r e s e a l i n g t h e flange. When l i n e 203 i s not i n use, t h e lower flanged j o i n t i s broken and t h e opening i s closed by an IN OR-^ blind flange t h a t has a 7/16-in. OD I N O R - ~ rod 12 i n . long welded t o it t o extend i n t o t h e d r a i n tank nozzle t o serve t h e same purpose as t h e tubing extension mentioned above. r i n g - j o i n t i s leak-detected during normal operation of t h e r e a c t o r . ,

The

= I

325 COVER-GAS SYSTEM

10.

The E R E cover-gas system supplies helium f o r use as an i n e r t gas above t h e s a l t surfaces, as a c a r r i e r f o r removing fission-product gases from t h e system, as a pressure source f o r t h e t r a n s f e r of salt from one v e s s e l t o another, as a means for control of t h e pressure within t h e system, and, i n t h e leak-detector system, as a monitor for leaks i n t h e mechanical j o i n t s . The helium introduced i n t o t h e system must be e s s e n t i a l l y f r e e of water vapor and oxygen ( < 1 ppm) t o reduce t h e likelihood o f oxide prec i p i t a t i o n i n t h e s a l t system. The cover-gas system consists of a helium supply, dryers, oxygenremovalunits, a t r e a t e d helium storage tank, and various valve manifolds and d i s t r i b u t i o n piping, as indicated i n Fig. 10.1. 10.1 Layout and General Description

Helium i s normally supplied from tanks mounted on a t r a i l e r parked

a t t h e northwest corner of t h e Diesel House, see Fig. 3.2.

The tanks

can be p e r i o d i c a l l y r e f i l l e d a t t h e Y-12 Plant a r e a .

Connections a r e made from t h e t r a i l e r t o two p a r a l l e l helium-treating systems and t h e treated-helium storage tank located i n t h e second bay of t h e Diesel House.

Each of t h e two treatment systems consists of a helium

dryer, a preheater, and an oxygen-removal u n i t .

The storage tank has a

capacity of 9 0 f't3 (STP). An oxygen analyzer continuously monitors t h e t r e a t e d helium f o r r e s i d u a l oxygen.

The t r e a t e d helium i s then piped t o

t h e various process a r e a s . A n emergency supply of helium i s provided by s i x standard helium

cylinders located i n t h e second bay of t h e Diesel House. 10.2

System Requirements

The primary r e q u i s i t e of t h e cover-gas system i s t o supply the q u a n t i t y o f "high-purity" helium necessary f o r use i n the f u e l and 140 coolant s a l t systems, and t h e a u x i l i a r y systems.

UNCLASSIFIED ORNL DWO. 04-600

LEAK DETECTOR SYSTEM

- 1

ENR IC HER SAM PL ER

[250 psig HEADER

"GRAPHITE

SAMPLER

RAD IAT1ON MONITOR

TO ATM.

O STACK

LRUPTURE DISC 5 0 psig -SPENT

FUEL PROCESSING LEVEL BUBBLERS

IL;

FUEL SYSTEM DRAIN TANKS

REATED HELIUM SURGE

HELIUM SUPPLY TRAl LER 2400 psig

I C O O L A N T PUMP AND DRAIN TANK

--\FUEL V

PUMP SWEEP GAS P

P O I L SYSTEMS

CON TAl NM ENT

SUPPLY HEADER

r---

REACTOR CELL

L-----A

I - ,1

ARRANGEMENT AT CONTAl NMENT C E L L W A L L TYPICAL FOR SUPPLY TO:

Fig. 10.1. Flow Diagram of Cover-Gas System.

F U E L PUMP SWEEP GAS FUEL PUMP L E V E L B U B B L E R S F U E L DRAIN T A N K S

'*'

327

The purge of helium through t h e f u e l pump bowl was s e t i n i t i a l l y a t

3.5 liters/min, and it was estimated t h a t 1 ppm of O2 i n a 3.5-liter/min helium purge stream would p r e c i p i t a t e 5.5 g of Z'02 per year (equivalent t o 18 g of uranium per year). 14' Neutron i r r a d i a t i o n of t h e f u e l s a l t

w i l l produce about 10 cc/day of oxygen i n t h e f u e l salt system when t h e

r e a c t o r power l e v e l is 10 Mw,142

which i s equivalent t o about 2 ppm of

i n a 3.?-liter/min helium purge stream. On t h i s basis, it was de2 cided t h a t t h e oxygen contributed as a contaminant i n t h e helium purge

gas supply should be held t o a value of near 1ppm, present e i t h e r as

moisture or as 0 2' The t o t a l volume of helium t o be supplied continuously by t h e cover-

F c

gas system i s about 5 ; 6 liters/min, d i s t r i b u t e d as follows: Sweep gas t o t h e fie1 pump

2.4 liters/min

Two f u e l pwnp bubbler l e v e l elements

0 09

Two coolant pump bubbler l e v e l elements

0.9 0.6 0.9

Purge t o t h e coolant pump

11 11

Two overflow tank bubblers I1 Additional intermittent flows a r e used for pressurizing t h e l e a k - e t e c t i o n system, f o r t h e t r a n s f e r of salt, o r f o r replacing t h e cover gas for- t h e l u b r i c a t i n g - o i l tanks. The cover-gas system w a s designed on t h e basis t h a t a treatment and 'I

supply f a c i l i t y with a capacity o f 10 liters/min, when used i n conjunction w i t h a WO-ft 3 (STP) t r e a t e d helium storage tank, would be capable of

handling t h e t o t a l demand.

An obvious requirement i n the treated-helium storage and d i s t r i b u t i o n system i s that it be as leaktight as possible t o prevent t h e l o s s o f h e l i u m

or i t s contamination by inleakage.

10.3 Flowsheet The flowsheet f o r t h e cover-gas system i s shown i n Fig. 10.2 (ORNL Dwg. D-AA-A-40884).

A l l t h e major piping i n t h e system i s 1/2-in. sched-40

s t a i n l e s s steel. A .

The helium i s normally supplied from trailer-mounted tanks containing 39,000 f t 3 (STP) a t 2400 p s i through t h e supply valve V-WOA on l i n e

-328

VENT

q , p 1.. V502A

m n DIESEL

1-UL

EWIPYNT DIESEL HOUSE

THIS DRAWING REFLECTS

AS BUILT CHAMGES

EXCEPT auul TRAL I ER

IS LOCATED m

--I

I -L I

329 500 downstream of V - P O A through valves V-%2A

o r V-502B v i a l i n e 502.

Two pressure indicators, PI-502A and PI-502B, show t h e emergency cylinder bank pressure.

The supply l i n e i s provided with a pressure indicator and alarm, PIA-500E, which alarms a t 500 p i g .

reducing valve, PCV-POG,

This i s followed by a pressure-

which lowers t h e supply pressure t o 2% p s i g .

This pressure i s monitored by a high-low alarm switch, PA-%OB, 275 p s i g and 200 p s i g . r)

set a t

The supply l i n e a l s o has a 1/8-in.-OD tubing take-

o f f , l i n e 548, leading t o t h e oxygen analyzer ~ 0 , - % 8 through valves V-98 and t h e check valve CV-548.

The supply l i n e then branches i n t o two p a r a l l e l 1/4-in.-OD,

0.065-in.

w a l l thickness, s t a i n l e s s s t e e l tubing l i n e s t o supply t h e two helium4

treatment s t a t i o n s . (V-WOA);

The i d e n t i c a l branches contain a hand valve, V-%OB

a t e e t o a purge vent, l i n e 505 ( l i n e 504); dryer No. 1 (No. 2 ) ;

a t e e leading t o a rupture d i s c , l i n e 507, t o be discussed subsequently; a t e e f o r a gas cylinder connection, l i n e V - P O C (V-500B); and an i s o l a t i o n valve, V - P O D ( V - P O C )

. The dryers, preheaters, and oxygen-removal u n i t s

w i l l be discussed i n Sections 10.5

- 10.8, following.

The 1/4-in. purge vents, l i n e s 504 and 505 mentioned above, a r e used t o vent helium from cylinders which can be connected a t V-WOB and V-g0C t o backflush and regenerate t h e helium dryers.

The vents combine i n t o a

s i n g l e tube, l i n e 505, which contains a flow indicator, FI-w5, before t h e helium is vented t o t h e atmosphere.

The rupture d i s c s i n l i n e s 506 and 507 a r e r a t e d a t 350 p s i g and provide overpressure p r o t e c t i o n for t h e helium-treating equipment.

These

l i n e s also c o n t a b high-pressure alarms, PA-506 and PA-507, which a r e s e t

a t 275 psig. The two branches of t h e treatment system recombine as l i n e 500, which

is connected t o a flow-indicating c o n t r o l l e r , FICA-500, arid a n air-operated c o n t r o l valve, FCV-500, which l i m i t s t h e supply of gas flow t o 10 l i t e r s / min

A second supply l i n e t o t h e oxygen analyzer, l i n e 549, i s taken o f f l i n e 3 0 a t t h i s poifit through t h e check valve, CV-$9,

and through t h e

stop valve, 17-99, The treated-helium storage, or surge, tank i s connected t o l i n e 500 v i a l i n e 597. This 1/2-in. l i n e contains a normally

330 open valve, V-597A,

and a Sranch connection t o valve V-597B, which

serves as a temporary vacuum connection.

A pressure gage, PI-He, on a

l i n e 597 indicates t h e surge tank pressure. Downstream of t h e surge tank connection, l i n e P O contains a pressure indicator, PI-YOA, and a pressure alarm switch, PA-YOK, which i s s e t t o a l a r m a t a low pressure of 100 p s i .

Following these instruments,

t h e helium supply t o t h e leak-detector system i s taken o f f , l i n e 514. (This 2 p - p s i supply l i n e i s routed through t h e water room and t h e e l e c -

The leak-detector system i s

t r i c service a r e a t o t h e t r a n s m i t t e r room.) described i n Section 11, following.

A branch from l i n e 514, l i n e 509,

supplies t h e sampler enricher, t h e graphite sampler and t h e coolant s a l t sampler.

(Line 509 t e e s o f f l i n e 514 i n t h e west tunnel and i s routed

through t h e coolant. drain c e l l , t h e s p e c i a l equipment room, then t o t h e Line 541 supplies t h e graphite sampler; l i n e 509, t h e

high-bay a r e a . )

sampler enricher; and l i n e 515, t h e coolant sampler. "he helium supply, l i n e Y O , then divides i n t o two p a r a l l e l l i n e s , l i n e 500 and l i n e 605, each o f which contains a pressure-reducing s t a t i o n s e t t o lower t h e helium pressure t o 40 p s i g .

These control valves, PCV-

S O C and PCV-605, have t h e usual i s o l a t i o n valves.

Af'ter l i n e s 500 and

605 r e j o i n , a pressure indicator, PI-WOM, and a high-low alarm switch, s e t a t 48 p s i g and 30 psig, monitors t h e pressure i n t h e continuing l i n e 500.

Line 500 contains a check valve, CV-SOB, monitor, RIA-PO.

ahead of a r a d i a t i o n

The helium supply t o t h e chemical processing c e l l ,

l i n e 530, i s taken o f f a t t h i s p o i n t . I n t h e water room, l i n e 508 branches from l i n e 9 0 t o a rupture d i s c , s e t a t 50 p s i g .

A p r e s s u r e - r e l i e f valve i s located i n t h e vent l i n e down-

stream of t h e d i s c . l i n e 932.

The vent discharges i n t o t h e v e n t i l a t i o n duct through

A low-pressure switch i n l i n e 500 closes two solenoid valves

i n t h e helium purge gas supply t o t h e pump bowl, l i n e 516, t o insure that back flow w i l l not take place i n t h a t l i n e i n event t h e rupture d i s c blows. Line 501 branches o f f l i n e 500 i n t h e west tunnel area t o supply t h e f i e 1 and coolant s a l t pump bubbler systems.

Line 517 i s connected t o l i n e

3 1 and supplies helium t o t h e drain, flush, and t r a n s f e r tanks i n t h e d r a i n tank c e l l , see Section 6.

This l i n e contains a flow r e s t r i c t o r ,

331

FE-517, which l i m i t s t h e flow t o 0.5 scf'm a t t h e 65%fill condition. The r e s t r i c t o r i s followed by a pressure control valve, PCV-517, which limits t h e pressure used f o r t r a n s f e r of salts, see Fig. 6.1 (ORNL Dwg D-All-A-40882). U n e 517 i s connected t o t h e valve manifold, HCV-572, HCV-574, and HCV-576, which serve t h e f u e l d r a i n tank No. 1, d r a i n tank No. 2, and t h e f u e l f l u s h tank, respectively.

The control valves i n

each of t h e t h r e e l i n e s , "72, 574, and 576, a r e followed valves and a hand valve i n s e r i e s . b

by two check

(The check valves and t h e hand valves

a r e contained i n a pot i n t h e e l e c t r i c service area, and t h e 1/4-in. l i n e from each hand valve i s run i n s i d e a 1/2-in. pipe t o t h e d r a i n tank c e l l w a l l penetration.)

Pressure t r a n s m i t t e r s f o r measuring t h e d r a i n

tank pressures, PRA-572,

PRA-574, and PM-576, a r e located i n each of

t h e t h r e e l i n e s downstream o f t h e check valves. A s shown in t h e cover-gas system flowsheet, Fig. 10.1, l i n e 511

leaves P O t o supply t h e coolant d r a i n tank. ing valves i n s e r i e s :

This l i n e has t h e follow-

V-511A, CV-511, PCV-511, HCV-211B ( t h r o t t l i n g ) ,

HCV-5lI-A (block), and V- 5l1B.

Line 512 branches o f f l i n e 311 upstream

of t h e first valve t o supply t h e coolant s a l t pump w i t h helium.

shown i n t h e coolant salt system flowsheet, Fig. 8.1 (ORNL Dwg D-AA-A-

40881), l i n e 5l2 contains a hand valve, V-512, a check valve, CV-512, and a flow control valve, FCV-512, with a maximum r a t e s e t t i n g of 1.47 liters/min. Line 510 branches off l i n e 9 0 i n t h e s p e c i a l equipment room and n

leads t o t h e s e r v i c e tunnel t o supply helium t o t h e l u b r i c a t i n g - o i l storage tanks.

A s shown on t h e l u b r i c a t i n g - o i l system flowsheet, Fig.

5.25 (ORNL Dwg ~-AA-A-40883), l i n e 5lO provides o i l t o t h e coolant pump lube o i l tank through valves V-5lOA,

PCV-5lOAl,

CV-510, and V-5lOB.

U n e 513 branches off l i n e 510 upstream of V-5lOA t o s i m i l a r l y supply t h e f'uel salt pump l u b e - o i l tank through valves V - 5 1 3 ,

PCV-5l3Al,

CV-513 and V-513B. The cover-gas system flowsheet, Fig. 10.2, a l s o shows a branch l i n e downstream of t h e l i n e 5 l O takeoff, l i n e 554, f o r attaching a possible helium recycle system. Another branch of l i n e 500, l i n e 516, supplies helium t o t h e f u e l -

. P

332 s a l t c i r c u l a t i n g pump a t a pressurk of about 40 p s i g and a maximum r a t e and of 0.085 scfh~. Line 516 contains #wo solenoid valves, HCV-516~

HCV-516C; an indicating flow c o n t r b l l e r and alarm, FICA-516; and a flow

control valve, FCV-516, followed by two check valves, CV-5l6A and CV-

5 1 6 ~ ,and a hand valve, v-516.

The f’unction o f t h e two check valves and

t h e two solenoid-operated valves i s t o assure that radioactive backflow cannot develop i n t h i s l i n e i n event of l o s s of pressure i n t h e helium supp l y . Line 516 then e n t e r s t h e r e a c t o r c e l l and goes t o t h e lower gas i n l e t on t h e f u e l - s a l t c i r c u l a t i n g pump. A capped t e e i s provided between t h e hand valve and t h e check valve t o enable t h e check valves t o be pressurized i n order t o t e s t l e a k t i g h t n e s s .

See Table 7.1 f o r helium supply

r a t e s t o f u e l pump. I

The check valves i n l i n e s 516, mentioned above, a r e located i n a containment p o t .

The l i n e i s reduced *om

1/2-in. pipe t o 1/4-in. pipe a t

t h e c o n t r o l valve and t o 1/4-in. -OD tubing a t t h e check valves. check valves t o t h e pump, l i n e 316 i s l/k-in.-OD

From t h e

tubing i n s i d e 1/2-in.

pipe t o provide double containment f o r t h e p o r t i o n outside t h e r e a c t o r c e l l and t o p r o t e c t t h e tubing i n s i d e t h e c e l l . 10.4

Helium Supply

The helium supply t r a i l e r has 30 cylinders, each 9-5/8 i n . diam by 21 ft long, with a t o t a l capacity of 39,000 ft3 (STP) a t 2400 p s i . A t t h e maximum estimated r a t e of use, 10 liters/min,

t h i s i s equiva-

l e n t t o a 76-day supply. The emergency helium supply c o n s i s t s of six standard cylinders arranged i n two banks of t h r e e cylinders each. min t h i s would be a 2.1-day supply.

A t a use r a t e of 10 l i t e r s /

However, by changing these emergency

cylinders i n banks of three, t h e emergency supply arrangement could be used i n d e f i n i t e l y .

10.5 Dryers The helium dryers i n l i n e s 500 and 503 each consist of a v e r t i c a l section of 2-in. 304 s t a i n l e s s s t e e l sched-40 pipe capped a t each end

333 and w i t h a 1/2-in. sched-40 pipe nipple welded t o each cap, see ORNL Dwg The pipe section i s about 4 1 i n . long and Contains a 30-in.

E-JJ-C-40855.

depth of drying medium supported on a 1-in. depth o f s t a i n l e s s s t e e l wool

a t t h e bottom and having about 1-3/8 i n . of t h e same wool a t t h e t o p . wool i s held i n place by 1/8-in.-thick p l a t e s w i t h 1/16-in.-diam 1/4-in. centers i n a square p a t t e r n f o r a t o t a l of 37 holes.

The

holes on

The p l a t e s

a r e tack-welded i n place. The drying medium i s Linde type l3x Molecular Sieve, 1/16-in.-diam pellets.

Each dryer contains about 2-1/2 l b o f p e l l e t s .

Each dryer bed i s designed f o r a flow r a t e of 10 liters/min (STP) and t o decrease t h e moisture content of the helium from 100 ppm t o e 1ppm on

an on-stream cycle of 15 days. 143

The a c t u a l moisture content of t h e

helium supply is thought t o be l e s s than 10 ppm so t h e bed l i f e should be well i n excess o f 15 days. The dryers are t o operate a t 250 p s i g and &OF.

For mechanical

strength considerations, however, t h e design conditions were taken as 400 p s i g and 7O0F. Since conventional hydraulic t e s t i n g could not be employed a f t e r f i n a l assembly, t h e units were pneumatically t e s t e d a t

3 0 p s i g (see ORNL Dwg E-JJ-C-40855). The normal flow d i r e c t i o n i s upward through t h e bed.

The dryers can

be regenerated by purging with a downward flow of f'resh helium while heating t h e bed.

Heat for t h e regeneration i s supplied by two P O - w ,

s t r i p heaters (Chromolox C a t . N o . S. E.

240-v

2550) about 25 i n . long strapped

z U.

t o t h e upper portion of t h e pipe section.

The heat i s controlled by

thermocouples located on t h e pipe w a l l about 1 i n . from t h e end of t h e heated section.

The w a l l i s heated t o a maximum of WOOF.

flow rate i s about 1.5 liters/min,

The purge

t h e e x i t gas temperature a t t h e com-

p l e t i o n of t h e drying cycle i s about P O O F , and t h e i n t e r n a l pressure during regeneration i s a maximum of 10 psig. The e n t i r e u n i t i s insulated with 1 i n . o f magnesia i n s u l a t i o n .

10.6 Preheater Each of t h e preheaters i n l i n e s fs00 and 503 i s designed t o heat a flow of 10 liters/min of helium t o 750OF, required f o r t h e oxygen-

. i

334 removal u n i t s . The preheater consists of a 2-in. sched-40 s t a i n l e s s s t e e l pipe section 10 i n . long with f l a t p l a t e s tack-welded t o each end, see ORNL Dwg. E-JJ-C-5%85.

Two 250-w, 120-v curved Chromolox s t r i p heaters,

8 i n . long, a r e strapped t o t h i s s h e l l . Two thermocouples mounted 4 i n . *om

t h e end a r e used t o coritrol t h e temperature.

The helium flow is

through a 10-f't length of s t a i n l e s s s t e e l tubing 1/4 i n . OD x 0.035 i n . wall thickness, coiled around t h e heater u n i t .

The e n t i r e assembly i s

covered with 3/4 i n . of t h e heat-conducting medium, "High Temperature Thermon," and insulated with 2 i n . of high-temperature i n s u l a t i o n .

10.7 Oxygen Removal Units I d e n t i c a l titanium sponge-type oxygen-removal u n i t s a r e i n s t a l l e d

i n l i n e s 3 0 and 3 3 t o assure t h a t t h e helium flow t o t h e cover-gas Oxygen contamination of t h e system contains l e s s than 1ppm of 0 2' helium supply i s l a r g e l y t h e r e s u l t of handling and should not exceed about 100 ppm.

The average O2 content m y be about 10 ppm.

A s indicated i n Fig. 10.3, t h e oxygen-removal u n i t c o n s i s t s of a

1 - i n . sched-5 titanium pipe 2 1 i n . long f i l l e d with an oxygen g e t t e r o f Electromet (Cleveland, Ohio) titanium sponge having a B r i n e l l hardness

of 125 and sized so t h a t 100% passes a 5/8-in. mesh screen and 95% i s retained on a 1/8-in. mesh.

The pipe i s mounted v e r t i c a l l y , using lava

spacers, inside 220-v l'Thermoshel1" ceramic heating elements (Cooley E l e c t r i c Co., Indianapolis), of 1200 w t o t a l capacity.

A stainless s t e e l

r e f l e c t o r , O.OO5-in. t h i c k , i s t i g h t l y wrapped around t h e heating e l e ments.

The heat r e f l e c t o r i s surrounded by a 3/4-in. thickness of

"Fiberfrax" QC-10 thermal insulation (Carborundum Company).

The as-

sembly i s contained i n s i d e a b i n . sched-40 s t a i n l e s s s t e e l pipe, with r i n g - j o i n t flanges a t t o p and bottom.

One-half-inch IPS pipe nipples

are provided a t top and bottom f o r t h e gas e x i t and i n l e t (see ORNL Dwg E-JJ-C-5623)The u n i t s operate a t 250 p s i g with a temperature i n t h e titanium sponge of 1200'F

+- W0F.

The design pressure i s 400 p s i g and t h e de-

sign temperature o f t h e pressure-containing 4-in. pipe i s a maximum of

335

UNCLASSIFIED ORNL-LR-DWG 68585

THERMOCOUPLE

@ GETTER TUBE @ HEATER, 1000 w

@ HIGH-TEMPERATURE INSULATION @ PIPE, 4 - i n . SCHED-40 SS @ FLANGES, 4-in. 1500-lb SS, WELDING NECK, RING JOINT

@ INSULATION

@ REFLECTOR /THERMOCOUPLE NTHERMOCOU PLE

THERMOCOUPLE

Fig. 10.3. Oxygen Removal Unit Cover-Gas System.

336 1000°F.

Leak t e s t s were made i n accordance with Par. UG-100 of Section

L( w

V I 1 1 of t h e ASME Code,47 using nitrogen a t 700 p s i g .

Helium leakage

l i t e r s (STP)/24 h r . A chromel-alumel thermocouple i s i n s e r t e d i n a well a short d i s -

w a s less than

This 1/8-in. -diam

tance i n t o t h e bottom i n l e t of t h e titanium sponge.

s t a i n l e s s steel-sheathed couple i s welded t o a trepanned hole i n t h e lower flange and has compression-type f i t t i n g s on t h e outside o f t h e flange

Three 1/16-in. -diam sheathed thermocouple leads a r e i n s e r t e d through t h e b i n . pipe w a l l near t h e top through lava-sealed packing glands, "Conax" C a t . No. MPG

- 1/16 i n . Two of these chromel-alumel

couples a r e located a t about mid elevation between t h e titanium pipe wall and t h e heater element, and t h e t h i r d is a t t h e top o u t l e t gas passage. Two 1/8-in. - d i m chromel-alumel sheathed thermocouples a r e provided on t h e outside of t h e 4-in. pipe. The two e l e c t r i c leads f o r t h e heater elements a r e brought through t h e &-in. pipe wall near t h e top i n individual s e a l s , "Ceramaseal" Dwg 804A38878. 10.8

Treated-Helium Storage Tank

A storage tank i s provided f o r t r e a t e d helium t o take care of t h e

i n t e r m i t t e n t periods when t h e helium demand i s considerably g r e a t e r than t h e normal continuous flow r a t e of 10 liters/min.

The volume of t h e

storage, o r surge, tank i s specified t o be 27 f t 3 so t h a t two f i e 1 s a l t t r a n s f e r s and two coolant s a l t t r a n s f e r s could be made without decreasing t h e helium supply pressure below 100 p s i g . The tank i s an 8-ft long section of 24-in. sched-30 pipe of 347 s t a i n l e s s s t e e l , capped a t each end.

It i s designed f o r a working pres-

sure of 2 3 psig and a t e s t pressure of 375 p s i g . temperature i s 80'~.

(STP) o f helium.

The design operating

The tank has a storage capacity of about 500 ft3

337

10.9 Bubblers f o r Indicating t h e Salt Levels i n t h e Fuel and Coolant Pump B o w l s and Overflow Tank The helium bubbler arrangement used t o indicate t h e l e v e l of salt i n t h e p m p bowls and t h e overflow tank i s described i n t h i s section since it i s c l o s e l y associated with t h e helium d i s t r i b u t i o n system.

b r i e f , t h e l e v e l i s determined by measuring t h e gas pressure required t o displace t h e l i q u i d salt i n d i p tubes which extend below t h e surface of t h e salt i n t h e pump bowls and overflow tank.

The dip-tube pressure

is measured by d/p c e l l s , referenced t o t h e pressure i n t h e vapor space.

10.9.1 Iayout and General Description The bubbler arrangements used on t h e f u e l and coolant pump bowls and overflow tank are i d e n t i c a l except f o r location and t h e containment of t h e f u e l system..

The f u e l pump bubbler i s described i n t h e following

paragraphs with t h e coolant pump and t h e overflow tank equipment and locations given i n parenthesis i n t h e same order. The f u e l pump bowl i s described i n Section 5.4.1.2.

As shown on t h e f u e l system flowsheet, Fig. 5.3 (8.1), t h e r e a r e two bubbler l i n e s , l i n e s 593 (598)(599) and 596 (595)(600), and one r e f erence l i n e , l i n e 592 (594)(589).

These l i n e s a r e fabricated of 1/4-in. -

OD x 0.065411. - w a l l s t a i n l e s s s t e e l tubing and a r e connected t o t h e

40-psig helium supply, l i n e 501, i n t h e t r a n s m i t t e r room.

Each l i n e has

a block valve a t t h e header and a t h r o t t l i n g valve t o a d j u s t t h e helium flow. A l l t h e bubbler l i n e s a r e routed p a s t duplicate r a d i a t i o n monitors, FUA-596A and RlA-596B, through conduit t o t h e s p e c i a l equipment room. I n t h i s l o c a t i o n t h e f u e l pump and overflow tank bubbler l i n e s have flow r e s t r i c t o r s i n s t a l l e d which l i m i t t h e flow i n l i n e s 593 (599) and 596

(600) t o 366 cc/min (STP) and i n l i n e 592 (589) (the reference l i n e ) t o 150 cc/min, when t h e helium supply pressure i s 25 psig. pump bubbler l i n e s ,

The t h r e e coolant

598, 595, and 594, continue t o t h e coolant c e l l where

s i m i l a r flow r e s t r i c t o r s a r e provided. The f u e l pump and overflow t a n k bubbler l i n e s e n t e r a containment tank (not required f o r t h e coolant pump l i n e s ) where each l i n e has %wo check valves i n s e r i e s (one check valve i n coolant system).

The check

. r

338 valves a r e followed by solenoid valves as follows:

l i n e 592, HCV-593-

Ld L

B2 ( l i n e 594, HCV-595-Bl) ( l i n e 589, HCV-599-B2); i n l i n e 593, HCV-593-

B3 ( l i n e 598, HCV-595-B3) ( l i n e 599, HCV-599-Bl); and i n l i n e 596, HCV593-Bl ( l i n e 595, HCV-595-B2) ( l i n e 600, HCV-599-B3). (See valve tabul a t i o n s i n Table 10.1.)

Following these valves, t h e reference pressure,

l i n e 592 (594) (589) is connected t o l i n e 596 (595) (600) through a solenoid valve, HCV-593-B5 (HCV-595-B5) (HCV-599-B>),and t o l i n e 593

(598) (599) through t h e solenoid valve HCV-593-a (HCV-595-&) (HCV599-a). These cross connections a r e f o r equalizing the pressure across t h e d/p c e l l s , which are connected between l i n e s 592 (594) (589) and 596 (595) (600),LI-596 (LI-595) (LIA-600), and between l i n e s 592 (594) (589) and 593 (598) (5991, m - 5 9 3 (=-598) (Lm-599). The lastmentioned d/p c e l l s serve both as l e v e l indicators and as an input t o recorders and an alarm system.

A s was mentioned i n Section 5.4.1.2, a

difference i n 2 i n . i n t h e distance t h e two d i p tubes extend beneath t h e surface o f t h e s a l t i n t h e pump bowls, 593 (598) i s t h e shorter, may permit v a r i a t i o n s i n t h e density of t h e s a l t t o be noted.

Both d i p tubes

extend t o t h e bottom o f t h e overflow tank since it i s d e s i r a b l e t o have duplicate readings on t h e q u a n t i t y of salt remaining. A connection i s made t o l i n e 592 (589) f o r t h e f u e l pump bowl pres-

sure transmitters, PRC-522A and PIA-522B, and t o 589 f o r PIA-589 and PXM-581.

Each of t h e l i n e s , 592 (594) (5891, 593 (598) (5991, and 596 (595) (600) has a hand valve outside t h e c e l l wall penetration. The l i n e s t o t h e f u e l pump and overflow tank a r e 1/4-in.-OD tubing run i n s i d e 1/2-in. pipe inside t h e r e a c t o r c e l l t o provide double containment.

10.9.2 Containment Tank The f u e l pump bubbler containment tank, or instrument box, i s a pressure-tight container for t h e above-ment ioned solenoid valves and d/p cells. The tank i s fabricated of a 21-in. length o f 24-in. sched-lOS, 304 s t a i n l e s s s t e e l pipe, with a flanged pipe cap a t each end t o give an o v e r a l l length of about 4.4 i n . (see ORNL Dwg E-JJ-D-55422). "he design pressure i s 50 psig but t h e normal operating pressure i s 0 p s i g

339

a t ambient temperatures. 1/4-in.,

The i n l e t tubing penetrations consist of

30,OOO-lb autoclave couplings.

The o u t l e t tubing penetration

i s a 6-in. sched-40 t a n g e n t i a l pipe nipple which i s a l s o welded t o t h e extension of t h e r e a c t o r c e l l penetration (see ORNL Dwg E-JJ-D-55428). The four e l e c t r i c a l conductor penetrations o f t h e tank have Amphenal s e a l s and serve t h e two d/p c e l l s from t h e 11 solenoid valves.

Two

1-in. pipe nipples extending from t h e top of t h e tank serve as containment for t h e 1/4-in. tubing leading from l i n e 522 t o t h e pressure c

t r a n s m i t t e r s PRC-522A and PIA-522B. The d/p c e l l s a r e accessible by opening one of t h e flanged ends of the tank and t h e solenoid valves may be serviced from t h e other end. 10.10

Piping, Valves, and Appurtenances

A l l piping i n t h e cover-gas system i s 304 s t a i n l e s s s t e e l sched 40.

The tubing i s 304 s t a i n l e s s s t e e l of various diameters and thicknesses. A l l f i t t i n g s are welded, w i t h t h e exception of t h e threaded valves i n

t h e portions of l i n e 500 and 502 that contain untreated helium. tubing f i t t i n g s a r e 30,OOO-lb

autoclave,

The

o r equivalent, w i t h t h e ex-

ception that t h e control valves i n t h e 1/8-in. l i n e s 548 and 9 9 have Swaglok compression-type f i t t i n g s . e

The hand valves are l i s t e d i n Table 10.1, t h e check valves i n Table 10.2, and t h e control valves, including t h e pressure regulators, i n Table 10.3.

340

Table 10.1 Cover Gas System Hand Valves Valve Numbers 500c

576

503c 504 35

592c 593c

514B

594c

516 519 541 548 549 372 574

59x 596c 598c 599c 60oc 601 606

Specification

Description

9gc

510~ 314A

513B

Hvs 1

Hoke, TY 440, socketweld to 1/4-in. OD tubing. Bellows-sealed bonnets. 300 series stainless steel.

Hvs lA

Same as HVS 1, but socketweld for 3/8-in. OD tubing.

Hvs lB

Same as HVS 1, but socketweld for 1/4-in. NPS pipe.

INS 2

Hoke, LY 473, socket-weld for 1/2-in. NPS pipe. Bellowssealed, 300 series S S .

SSD

Crane, socket-weld to 1/2-in. NPS pipe, bellows-sealed, carbon steel. Hoke, Y 344, threaded for 1/4-in. pipe, packed bonnet.

59% 59a 5% 595B 596B 598B

599B 600B

Hoke, A 434, forged brass, 1/4-in. NPS male pipe thread, bellows-sealed, Kel-F tip

341

Table 10.2

Valve Numbers

500~ 510 51a 51% 57% 574A 5 7 a

58%

500B 513 516~ 519B 572B 5743 576B 589B > 592B 593B 595 596B 599B

59% 59% 594 59a 598 59%

600B

6OOA

6O6B

Cover Gas System Check Valves Description

Circle Seal, Dwg P705, 3/8-in. Aminco connection, s o f t seat, spring-loaded, 300 series stainless steel.

6O6A

584

549

Nupro, 2C, with 1/8-in. Swaglok connections, 300 series SS.

511

512

Nupro, 4C2, modified for autoclave connections, 300 series SS.

Table 10.3.

Msm Number PCV y o c PCV W G FCV P O J PCV 510~1

HCV 5 1 m HCV 511Bl HCV 511~1 FCV 512A1 PCV 5131 HCV 516~1 PCV 517A1 HCV 519A1 HCV 572 HCV 574

Specification

64 61 18 18 18 18 18 18 18 18 18 18 18

HCV 576

18 18

PCV 605

*Regulator

Cover Gas System Control Valves and Regulators Size, in.

Fail Position

1/4 Threaded

* *

3/8 Autoclave

0.0045

1/2 Autoclave

0 -0035

1/2 Autoclave

3- 5

1/2 Autoclave

0 DO77

1/2 Autoclave

0.077 o .om83

1/2 Autoclave

0.0035

1/2 Autoclave

o ,0035 0a 0 7 7 o .00083 3.5 3.5 3-5

1/2 Autoclave

Closed Closed Closed Closed

1/2 Autoclave

Closed

1/2 Autoclave 1/2 Autoclave

Closed Closed Closed

1/2 Autoclave

Closed

1/4 Autoclave

1/2 Autoclave

Closed Closed Closed Closed

Make

Comment

Fisher Fisher Masoneilan Masoneilan Fulton (HRT) Masoneilan Masoneilan

Buna-N diaphragm

Masoneilan Ma soneilan Masoneilan Masoneilan Masoneilan Fulton (HRT) Fulton (HRT) F'ulton (HRT) Fisher

Buna-N diaphragm

Table 10 . 3 Valve Number

- Msm

(continued )

Specification

Port Size

Size, in.

Fail Position

Make

139

3/32 in.

1/4 Autoclave

Closed

Valcor

Comment

Hev 593-31 ' HCV 593-B2

593-B3 HCV 593-B4 HCV '593-35

HCV'

HCV 595-Bl HCV 595-B2

HCV-595-B3 HCV 595-B4

Hcv 595-B5 HCV 599-Bl HCV 599-B2 HCV 599-B3 HCV 599-B4 HCV 599-B5 HCV 606

Solenoid-operated

344 11. LeAK DETECTOR SYSTEM A leak detector system i s used t o monitor a l l flanges i n the MSRE

system which could permit the escape of radioactive materials. J o i n t s i n lines containing lubricants o r coolants important t o the operation and safety of the reactor are also leak detected. In addition, a l l flanges w h i c h must be maintained by remotely operated tooling are provided w i t h leak-detected type joints t o serve a s an indication of satisfactory reassembly. 145 There are about 100 leak-detected flanges in the system. The leak detector system operates on the principle of maintaining sc an over-pressure of 100 psig of helium at all joints. In event of a leak i n the process system, heliumwill flow into the affected system. The resulting loss i n pressure at the leak detector system supply headers actuates an alarm system. Each of the 60 o r more leak detector lines is provided w i t h a hand valve at the header t o permit isolation of the l i n e t o determine the location of the leaking joint. 11.1 Layout and General Description

In brief, the leak detector system consists of eight manifolds, o r

headers, mounted in a leak detector station cabinet, 2-ft x 4-ft x 6-1/2 f t , located on the south side of the transmitter room.

(This room i s at the 840-ft elevation, east of the drain tank c e l l and north of the reactor cell. See Fig. 4.4.) The headers are connected t o the helium supply from the cover-gas system and t o the leak detector l i n e s leading t o each flange. Ieakage is detected by header pressure drop and measured by the rate at w h i c h the pressure in the header drops a s compared t o an equivalent tank volume (500 cc). This arrangement p a r t i a l l y compensates f o r pressure changes i n the system due t o ambient temperature variations i n the transmitter room.

*By definition, i f a continuous inflow of helium i s required t o a part of the system, it i s termed a "buffer" flow rather than leak detection.

345

The leak detector l i n e s leading t o the reactor, drain tank, and

f u e l processing c e l l s , pass through the f l o o r beneath the leak d e t e c t o r system cabinet and m e routed t o the c e l l w a l l penetrations i n "Iay-InDucts."

The general location of the l i n e s i s shown i n Fig, 11.1. The

leak detector l i n e s t o the coolant c e l l and vent house a r e run through conduit around the reactor c e l l t o the s p e c i a l equipment room; from here t o the point of application they ase mounted on "Unistrut."

The leak

d e t e c t o r tubing i n s i d e the reactor and drain tank c e l l s i s e i t h e r sup-

ported by "Lay-In-Ducts" o r mounted on "Unistrut '' Figure 11.2 shows a t y p i c a l leak-detected j o i n t .

The leak detection

arrangement as applied t o a freeze flange i s shown i n Fig. 5.29.

The oc-

tagonal O-ring type gasket i s d r i l l e d t o pennit transmission of the helium gas pressure t o a l l four of the sealing surfaces.

On some l i n e s , one leak detector i s connected i n s e r i e s t o serve two o r more s e t s of flanges. Where valves have leak-detected j o i n t s , both sets of the valve flanges a r e servedwith one leak detector l i n e , see Fig. U.3. Where both flange faces i n a p a i r must be removable f o r maintenance reasons, such as on the pwnps, the freeze flanges, etc.,

it i s necessary

t h a t the leak d e t e c t o r l i n e s have disconnects which can be remotely ma-

nipulated.

These disconnects a r e described i n Section 11.6, following.

The leak detector system i s constructed of 304 s t a i n l e s s s t e e l . The tubing i s 1/4-in.

sched 40.

OD x 0.083-in.

w a l l thickness and a l l piping i s

A l l valves a r e bellows sealed, as described i n Section 11.5.

If it i s assumed that the leak r a t e of

cc/sec determined i n

the development of the freeze flanges (pp 41-45 Ref 38) i s representative

of the average leak r a t e of t h e 100 flanges i n the MSRE system, the t o t a l leakage i s i n t h e order of 6 cc/min. header,

This amounts t o about 75 cc/min per

Taking the average volume of a header and i t s connected l i n e s

t o be about 2,000 cc, t h i s l o s s of helium amounts t o a pressure l o s s of about 0.66 psi/hr,

The minimum f u l l range of the d i f f e r e n t i a l - p r e s s u r e

cell used t o i n d i c a t e t h e pressure difference between the header and the volume tank is 5 in. of water, o r about 0.18 p s i . A change i n the difI

, !

f e r e n t i a l pressure of 0.05 p s i per hour (28$ of f u l l range) i n d i c a t e s a

leak r a t e of about 0.04 cc/min

(6.67 x

cc/sec).

346

7' I

+ I

347

Unclassified ORNL DWG 64-8833

LEAK DETECTOR L I N E FROM LEAK DETECTOR STATION

SEALING SURFACES O-RING GASKET

--c SEALING SURFACES FLANGE OR MAY BE CAPPED OFF

Fig. 11.2. Schematic Diagram of Leak-Detected Flange Closure.

. I

348

.. Unclassified

ORNL DIG 64-8834

ANY L I N E R E Q U I R I N G LEAK DETECTOR SERVICE

REACTOR

REMOTE DISCONNECT FLANGE

PERMANENTLY INSTALLED PIPE LEAK DETECTOR L I N E

F i g . 11.3. M e t h o d o f U t i l i z i n g One L e a k Detector L i n e to Serve Two Flanges in Series.

349 11.2

Flowsheet

The f l a t s h e e t f o r the leak detector system i s shown i n Fig, 11.4

(ORNL drawing D-AA-A-40890). Helium i s supplied at 250 psig through 1/2-in, Line 514 from the cover-gas system (see Section 10.3).

This l i n e reduces t o l / b i n .

tubing inside the leak detector system cabinet.

The helium i s supplied

through valves V-514-B,

CV-514, and PCV-514, the l a t t e r regulating the

pressure t o 100 psig.

A f t e r passing a connection through which helium

can be supplied i n an emergency, the f l o w i s d i s t r i b u t e d t o each of the e i g h t headers.

The d i s t r i b u t i o n l i n e , Line 514, contains a high-law

pressure alarm switch s e t f o r the 90 t o 110 psig range.

Each helium

supply t o a header i s provided w i t h an i s o l a t i o n valve.

Each header

serves as a valve manifold f o r ten 1/4-in.

leak detector lines, which

are grouped by application and location, as shown i n Table ll.1. Lines 410 through 414 on header 401 serve the reactor c e l l freeze flanges.

Lines 415 through 419 are spare leak detector l i n e s leading

All t e n of these lines have one hand valve at the header and ase 'provided with disconnect couplings inside the reactor i n t o the reactor c e l l .

cell. Header 402 serves the reactor c e l l helium l i n e s .

Each of these

leak detector lines, k0 through 429, has two hand valves i n s e r i e s , w i t h the inner, or "B" valve, being used t o prevent backflaw From the c e l l i n event maintenance i s required on the operational valve, "A."

Each of these leak detector l i n e s i s connected t o two pairs of flanges i n series.

There are no spare l i n e s on t h i s header.

Header 403 monitors reactor c e l l water l i n e s .

Leak detector Lines

430 through 434 are connected t o half-flanges i n the thermal shield water (These half-flanges axe i n s t a l l e d where t h e welded piping system i s l i k e l y t o be cut for maintenance prdcedures and Later rejoined by

piplng.

spool pieces with bolted mechanical joints.) other water piping flanges.

Lines 435 through 439 derve

Each of these t e n l i n e s has one hand valve

a t the leak detector system header. c

Header 404 serves miscellaneous reactor c e l l flanges, such as t h e o i l piping flanges (Uak Detector Lines 440, 441, and 4&), and the pump

350

I I

V403A'

V40U

V40S

V402

8 4t LW @

woo

TO CFlOO

v406a

V440 VI050

V404B

440

LINE 701) CLINICS ~ 4 -

COOLANT PUMP LOWLR CLANOL COOLANT PUYP UPPfR CLAN=

VOCUY TANK 500cc

P LOWCR CLANOE TO FFZOO CUTURL

WCLR FLANOE

TO CCZOl CUTURL

UYPLER FLAMES

UW sm n w . s

CESS1 FLUIOLS SCYRE

100

PSlC

mcc

WARE TO RC

NOTES: I-LOUIPYLNT IN€

SHOWN TO W LOUTCO IN TU€ TRANSYITTER ROOM.

X I CLANGLS

L 522 FLANCES

V5140 7.50 P I 1 0

HCLIUY

LINE 5*2

4W-R

FLANCES

LINE 5S6 FLANU8

VWaA vu90

LUE C O O T W E E S

V410

V411

INES 844f.O,84Ys

6FLY(QES

THIS DRAWING REFLECTS INE 644H. 2 FLANGfS

w. v432

INL M40,0,E, 6 CLANOES

V4I3

v434

INE 044C, 2 F L A N W

435

v435

V4M

v4.37

AS BUILT CHANGES UTI

9-23-64

INL 830 fLANOC8 .WE

831 FLAN*CS

INK

a16 CLANCC

IYC

0 4 6 FLLINIC

.INK

8 4 0 CLANS€

INE

841 CLANOE

v41*

** k

351

Table 11.1. Bak Detector System Headers ~~

Header No.

401 402

403 404 405 406 407 408

General Service Reactor c e l l freeze flanges Reactor c e l l gas lines Reactor c e l l water lines Miscellaneous reactor c e l l flanges Drain tank c e l l gas lines Drain tank c e l l steam and water lines Miscellaneous Fuel processing c e l l

Connected Bak Detector Lines

NOS. 410 - 419 NOS. 4-20 429 NOS. 430 439 NOS. 440 - 449 NOS. 450 459 NOS. 460 469 NOS. 470 479 NOS. 480 489

352 and r e a c t o r neck flanges (Lines 443 through 446).

have two valves i n s e r i e s at the header. connect couplings inside the c e l l .

Lines 443 through 446

Lines 447, 448, and 449 a r e spare

Header 405 i s used t o monitor gas piping flanges i n the drain tank Line 450 i s a spare leak detector l i n e t o this c e l l .

Lines 451

through 459 have two valves in s e r i e s at the header. Header 406 serves the drain tank c e l l steam and water piping flanges. Lines 460 through 465 a r e used f o r this purpose and the remaining four l i n e s serve as spares f o r the drain tank c e l l . Header 407 i s used f o r flanges c l a s s i f i e d as miscellaneous.

These

include t h e coolant salt circula.ting pump upper and lower flanges (IRak Detector Lines 470 and 471), and flanges a t the gas c o n t r o l valves i n t h e coolant c e l l and i n the vent house (kak Detector Lines 472, 473, and 479).

Lines 474 through 476 monitor flanges on the f u e l drain tanks. U e s 473

These three l i n e s have disconnects i n s i d e the drain tank c e l l . through 476 have two valves in s e r i e s a t the header.

Line 478 is a spare

l i n e t o the coolant c e l l . Header 408 monitors flanges in the f u e l processing c e l l .

Lines 480

and 481 serve flanges on the c o n t r o l valves HCv-692 and HCv-694. and 483 are i n s t a l l e d spares t o the e l e c t r i c a l service area.

Lines 482

Lines 484 and

489 are spares. A l l eight of the above-mentioned headers a r e connected through hand valves t o Line 400, which leads t o the 500-cc tank through a normally closed block valve,

V-4-00.

A d i f f e r e n t i a l - p r e s s u r e c e l l , PaT-4-00, con-

nected between this tank and Line 4-00, senses small changes in the header

In addition, Line 400 has a high and 1m pressure switch which annunciates an alarm on t h e main c o n t r o l panel i n event of deviation from the 90 t o 110 psig s e t range. pressure compared t o t h e tank pressure.

11.3 Headers i

Each header c o n s i s t s of a 19-1/2-in.

long section of 1-1/2-in.

sched

40, 304 s t a i n l e s s s t e e l pipe, capped a t each end (see ORNL drawing D-JJ-D-55403).

A l-l/4-in,-diam

Lines 444 through 449 have dis-

l i n e s f o r the r e a c t o r c e l l . cell.

4iigd:

s t a i n l e s s s t e e l rod i s enclosed i n s i d e

353

each header t o reduce the free volume.

To assure t h a t this inserted

rod does not block any of the l e a k detector openings, three equally spaced w i r e s , 0.040-in. d i m , are tack welded the length of the insert t o space it c e n t r a l l y within the header pipe.

The free volume of any

branch was limited so that the response t i m e f o r a leak of 1 cc/min would not be less than 0.5 psi/hr (p 2 Ref 145). There are t h i r t e e n 1/4-in. OD x 0.083-in. w a l l thickness tubes

welded t o each header.

To these a r e connected the t e n l e a k detector

l i n e s , the helium supply from Line 514, the connection t o Line 400 and t h e tank, and a l i n e t o a pressure gage. 11.4

Valves

Each tubing l i n e contains a miniature, bellows -sealed hand valve (Hoke, Type 480).

These valves were salvaged from the Homogeneous Reactor

Test (BE-2) and were completely inspected, reconditioned and t e s t e d . Leak detector l i n e s which monitor flanges i n d i r e c t contact with radioa c t i v e gases have two of these valves i n s t a l l e d i n series a t the header

so t h a t t h e inner valve can be closed t o i s o l a t e the system while the operational valve is being repaired. 11.5

Disconnects

I n t h e cases where flanges inside the reactor c e l l must have both faces removed t o e f f e c t a maintenance procedure, the associated leak det e c t o r l i n e s must have nearby disconnects which can be operated by remote tooling.

These couplings must be as f r e e as possible from any leakage.

The design selected f o r use i n the =RE, as shown i n Fig. 11.5, was J'

developed i n t h e ORNL Chemical Technology Division and i n t h e Reactor D i -

vis ion.

The sealing p r i n c i p l e is based on e l a s t i c deformation of a

'polished metal cone when inserted i n a polished seat.

The block on which

the male cone is mounted and t h e block containing the matching seat are of t h e proper dimensions t o make contact t o prevent t h e cone from being jammed i n t o t h e seat and deformed p l a s t i c a l l y .

The two blocks are held

together by a simple but positive yoke assembly.

The s i n g l e b o l t on

t h i s yoke f a c i l i t a t e s operation by remotely handled t o o l s .

. 354

Unclassified ORNL DWG 6-4-8835

A = Plpe or tubing bore, 2 0.0025 in. B = Major male diameter boss before taper, +O.OOO 0.001 i n . C = Major fansle diameter before rounding entrance

- --

edge, + 0.001 0.OOO in. D = no, +Oo 1/2:, included angle tapered cone. E = 23-l/2O, + 1/2 Oo, included angle tapered hole.

_ . _. t-

Trepan l/&s-in. -us

x 3-in. Bolt

'I I

4 l

+" l d - i n . AA

section AA

0.250 0 398

Contact

Well

0.400

0.375 0.533 0-535

0 0035

0.040

Figure 11.5.

0.500

0.750 0 0938

0.670

0.625 0.803 0.805

0.045

0.050

0.055

0.668

0.935

Leak Detector System Block Disconnects w i t h Yoke.

square

355

u c

, ~

Tests made during development of the coupling indicate that a leak rate of less than loo6 cc/sec (STP) can be expected even a f t e r the joint has been broken and remade t h i r t y times or more. These tests were made at room te~nperature.’~~A t temperatures of a few hundred degrees (OF), it was indicated that the joint might be manipulated at l e a s t twenty times before the leak r a t e was increased. It i s anticipated that all plIsRE disconnects w i l l operate at the c e l l ambient temperature of about 150°F. A light coating of an alcohol-graphite mixture i s recommended f o r the cone

before the joints are made.

11.6

meal =ak Detectors

The flanges in the fuel and coolant pumg lubricating o i l systems

are provided w i t h local leak detector connections t o which helium gas cylinders can be connected when a leak is suspected. This leak detection arrangement is not connected t o the reactor leak detector system. Each of the lube o i l packages contains nine local leak check points, see the lubricating o i l flowsheet, Fig. 5.25 (ORNL drawing D-AA-A-40885).

. C

356

12. OFF-GAS D1SPOSA.L SYSTEM

The off-gas f a c i l i t y provides f o r t h e s a f e disposal of radioactive gases discharged from t h e MSRE. of gas flow:

The system handles t h r e e d i f f e r e n t types

(1)t h e continuous discharge of helium containing highly

radioactive fission-product gases swept from t h e f u e l s a l t c i r c u l a t i n g pump bowl; (2) intermittent, r e l a t i v e l y l a r g e flows of helium containing,

a t times, s i g n i f i c a n t amounts of radioactive gases and p a r t i c u l a t e s , such as t h a t discharged during s a l t t r a n s f e r operations; and (3) flows of up t o 100 cfm of very low a c t i v i t y c e l l atmosphere gas

(5% 02’ 95% N2), which

is ejected e i t h e r i n t e r m i t t e n t l y o r continuously t o maintain t h e r e a c t o r

and d r a i n tank c e l l s a t sub-atmospheric pressure. ,

The unstable isotopes of iodine and bromine r e s u l t i n g f r o m t h e f i s sioning of t h e 23%J

i n t h e f u e l s a l t l a r g e l y remain i n t h e s a l t solution

as complex halides u n t i l they decay t o elemental xenon and krypton.

Since

it i s d e s i r a b l e t o remove t h e l3?Xe from t h e f u e l s a l t c i r c u l a t i n g system

because of i t s high cross s e c t i o n f o r capture of neutrons ( a = 3.5 x 10 b ) , it and other fission-product gases a r e swept *om t h e f i e 1 pump bowl by a helium gas flow of about 4 liters/min (0.13 cfm a t SW). When operating

a t t h e 10-Mw r e a c t o r power l e v e l , t h e a c t i v i t y of t h i s stream leaving t h e pump i s about 280 curies/sec.

148

The gases a r e held i n t h e piping f o r about two hours for t h e s h o r t l i v e d isotopes t o decay. vated charcoal.

They then pass i n t o a water-cooled bed of a c t i -

The adsorbed xenon i s retained i n t h e bed f o r a t l e a s t

90 days and t h e krypton i s held f o r 7-1/2 days o r more.

W i n g t h i s time,

e s s e n t i a l l y a l l t h e fission-product gases decay t o s t a b l e elements, some of which a r e s o l i d s that remain i n t h e charcoal. isotopes, 85Kr, 13%e

Only t h r e e radioactive

and 13?Xe, e x i s t i n any s i g n i f i c a n t amounts i n t h e

helium c a r r i e r gas leaving t h e charcoal bed.

(See Table 12.1)

Of these,

t h e 85Kr with i t s half-life of 10.27 years, i s of t h e g r e a t e r concern. The maximum discharge rate o f t h i s isotope i s 5 c u r i e s per day.

The e f f l u e n t from t h e charcoal bed i s monitored f o r a c t i v i t y before passing through roughing f i l t e r s and then absolute f i l t e r s having an e f f i c i e n c y of 99.9% f o r p a r t i c l e s greater than 3 microns i n s i z e .

The gas

357 Table 12.1 Design Data Off-Gas Disposal System Charcoal Adsorber Beds Off-gas charcoal beds (four sections) Design flow (two sections), cf’m Design temperature, 0F

0.15

250

Design pressure, psig

50 Xenon holdup (minimum for two sections), days 90 Heat load, (two sections) kw 10 Charcoal bulk volume, (two sections) f’t 3 44 Charcoal weight, (two sections) lbs 1450 Length (each section), 1-1/2 in. pipe, f’t 80 3 in. pipe, f’t 80 6 in. pipe, ft 84 Over-all pressure drop, psi 1.5 Auxiliary charcoal bed Design flow, cf’m 1 0 Design temperature, F 85 Design pressure, psig 50 3 Charcoal bulk volume, f’t 16 Charcoal weight, lbs 530 Length, 6 in. pipe, f’t 80

Over-all pressure drop, p s i

Capacity at breakthrough, f’t3 , stp Stack Fans (two) Horsepower Capacity at 11.5 in. water, cfm

Design flow rate,-cfm Exit roughing filter ~

Type 2 Area, ft

Depth, in.

1.25

144

50 21,000 20,000

Fiberglass, deep bed pocket 350 for each of 3 banks 1/2 of 3.25 micron fiber dia 1/2 of 1.25 micron fiber dia

358

Table 12.1 (Continued 1 Efficiency

90-958by NBS test with atmospheric dust

Initial pressure drop, in. of water

0.6 @20 ft/ain

Absolute filter Fiberglass, high efficiency

m e Area, f't

Depth, in. Efficiency Initial pressure drop, in. of water

24 for each of 3 banks 1142 99.97% > 0.3 micron 1.05 @ 280 f't/min

Stack Height, f't Diameter, ft

100

4 at bottom, tapering to 3 at 25 f't elev. 3 for top 75 ft

Activities leaving stack, pc/cc 83"Kr (Half-life 114 m)

85% 85Kr 88Kr

88Rb l3l"ke 133"ke '33xe

'I II

7.0 x 10-l'

4.36 h

1.0 x lo-8

10.27 y

6.2 x 1.3 x

2.77 .. h 17.8 m

1.2 x 1Q-l1

12.0 d

1.0 x

2.3 d

6.3

5.27 d Expected dilution to maximum ground concentration

LO-^^

6.1 10-7 4 -10

359

.cd

i s massively d i l u t e d with atmospheric a i r and discharged f r o m t h e top of

a 100-ft-high s t a c k about 110 ft south of Building 7w3.

The concentration

of 83Kk i n t h e s t a c k discharge i s a maximum of 6.2 x 10-6 microcuries/cc,

which i s within t h e accepted tolerance l e v e l .

The ground l e v e l concen-

t r a t i o n i s estimated t o be l e s s than t h i s by a f a c t o r that may be as great as 10,000.

12.1 Layout and General Description I n addition t o t h e f u e l pump bowl, other equipment vented t o t h e o f f gas system includes:

t h e t h r e e f u e l s a l t d r a i n tanks i n t h e d r a i n tank

c e l l , t h e f u e l pump s h a f t s e a l seepage i n t h e r e a c t o r c e l l , t h e graphite

sampler, a l s o i n t h e r e a c t o r c e l l , t h e sampler-enricher i n t h e high-bay area, t h e coolant s a l t pump s e a l and pump bowl

i n t h e coolant c e l l , t h e

two l u b r i c a t i n g o i l system packages i n t h e service tunnel area, t h e coolant salt d r a i n tank i n t h e coolant d r a i n c e l l , and t h e reactor and drain tank

containment c e l l s themselves. Design data for t h e off-gas system a r e summarized i n Table 12.1. The schematic diagram i n Fig. 12.1 and t h e following b r i e f o u t l i n e of t h e course of t h e f u e l c i r c u l a t i n g pump bowl off-gas l i n e , and t h e equipment associated with it, w i l l serve a s a general description of t h e off-gas system.

The gases leave t h e bowl through a 1/2-in. s t a i n l e s s

s t e e l pipe, l i n e 522.

. c

The pipe s i z e changes t o 4 i n . a t t h e disconnect

flange and p a r t i a l l y c i r c l e s t h e inside w a l l of t h e containment vessel. The t o t a l length of b i n . pipe i s about 68 ft, which includes a serpent i n e section, and provides a holdup volume of about 6 f t 3

. This i s suf-

f i c i e n t f o r about one hour's delay f o r t h e decay of fission-product isotopes.

A 4-rt horizontal length of t h e 4-in. l i n e 522 i s enclosed

i n a 6-in. sched 10 pipe a t t h e 831-ft elevation and 400-600 s c f b containment atmosphere gas (93%N

5% 02) i s introduced through l i n e

960 i n t o t h e annular space t o help cool t h e off-gas. The off-gas l i n e continues through t h e r e a c t o r c e l l wall penetration a s 1/2-in. pipe and across t h e coolant s a l t areas as 1/4-in. pipe encased i n a 3/4-in. pipe, which, i n turn, i s surrounded by about 4 i n . of l e a d shielding.

Line 522 then passes through valves i n a pressure-tight

RESTRICTOR\

UNCUS5 IFlED ORNL OWQ. 64-594R

HELIUM SUPPLY

BUILDING

--------

SYSTEM BLOWER

FILTER

21,000 cfm FAN

HELIUM SUPPLY

'DRAINS

REACTOR ON HIGH ACTIVITY

Fig. 12.1. Schematic Diagram of Off-Gas System.

0 0

REACTOR CELL

instrument box located i n t h e lower portion of t h e vent house.

From here

it continues a s a 1/4-in. pipe i n an underground shielded duct t o an underground valve box and then t o t h e charcoal bed c e l l .

This c e l l i s located

below grade j u s t south o f t h e vent house, a s shown i n Fig. 3.2.

The c e l l

was an e x i s t i n g f a c i l i t y consisting of a 1 0 - f t - d i m x 22.7-ft-deep reinforced concrete p i t with a 3-f't t h i c k removable concrete cover. The off-gas pipe, l i n e 522, connects t o t h r e e v e r t i c a l 20-f't high U-tubes of 3-in. pipe which provide about 7 f't3 of holdup volume and an a d d i t i o n a l one hour of residence time.

The gas then enters one o f two

a c t i v a t e d charcoal beds, t h e other bed a c t i n g a s a spare.

Each of t h e

two beds consist of two v e r t i c a l sections of U-tubes w i t h t h e pipe s i z e varying f r o m 1-1/2 i n . t o 6 i n . , and each containing about 22 f t 3 of a c t i v a t e d charcoal.

The charcoal bed c e l l i s f i l l e d w i t h water and t h e

beds a r e cooled by t h e wa%er flow through t h e c e l l . The e f f l u e n t from t h e charcoal beds, wnich consists primarily of t h e helium c a r r i e r gas*, flows through an underground 1/2-in. pipe t o an underground valve box and then t o a f i l t e r p i t located about 75 f't south of Building 7503.

(See Fig. 9 and Section 4.7)

The reinforced concrete

f i l t e r p i t i s about 21 x 29 ft, varies from 3-1/2 f't. t o 7-1/2 ft i n depth, and i s covered by 1-1/2-ft-thick

concrete roof plugs.

The off-gas mixes

w i t h about 21,000 cfm. of a i r drawn through t h e f i l t e r s by a 50-hp fan

(an i d e n t i c a l fan i s i n s t a l l e d a s a s p a r e ) and, thus massively d i l u t e d , is discharged f'rom a 3 - f ' t - d i a m

x 100-ft-high s t e e l s t a c k located about

110 f't south of Building 7503.

O f f - g a s vented fYom other p o i n t s i n t h e MSRE system i s handled

s i m i l a r l y and u t i l i z e s &ch of t h e same equipment.

The gas discharged

fYom t h e f u e l d r a i n tanks flows through a 1/2-in. pipe crossing t h e coolant s a l t a r e a t o t h e aforementioned instrument box a t t h e vent house, and t o an a u x i l i a r y charcoal bed located i n t h e charcoal bed c e l l .

The

isotopes i n t h i s stream have already decayed t o reduce t h e heat r e l e a s e

rate s u f f i c i e n t l y t o permit use of l a r g e r diameter pipe f o r t h i s charcoal

*There a r e no provisions i n t h e MSRE for processing and reuse of helium. Consideration has been given t o adding t h i s f a c i l i t y l a t e r i n t h e experiment e

bed.

Two v e r t i c a l u - t u b e sections of 6-in. pipe contain about 16 ft3 of

a c t i v a t e d charcoal.

The outflow of t h i s bed j o i n s t h e flow from t h e main

charcoal beds, and other off-gas streams, and i s monitored, f i l t e r e d and d i l u t e d before discharge up t h e off-gas s t a c k t o t h e atmosphere. Cover gas vented from t h e coolant s a l t c i r c u l a t i n g pump bowl and from t h e coolant salt d r a i n tank bypasses t h e charcoal beds i n t h e o f f gas system, but i s monitored and f i l t e r e d before discharge. The c e l l atmosphere gas i s evacuated from t h e r e a c t o r containment

v e s s e l and t h e d r a i n tank c e l l by blowers located i n t h e s p e c i a l equipment room.

The blower discharge, after passing through a gas cooler, i s

f o r t h e most p a r t , returned t o t h e c e l l s t o cool s p e c i f i c items o f equipment, such as t h e upper portion of t h e f i e 1 c i r c u l a t i n g pump bowl. component cooling system i s described i n Section 16.)

(The A small s i d e stream

o f t h e blower discharge i s vented through t h e off-gas system t o atmosphere t o maintain t h e c e l l s below atmospheric pressure.

This 1-1/2-in.

line

passes through t h e vent house, where t h e gas i s monitored, and may be sampled when necessary, before being f i l t e r e d and discharged up t h e s t a c k . The f i l t e r s , s t a c k fans, and s t a c k a r e described i n Section 1 3 . 12.2

Flowsheet

The off-gas system flowsheet i s shown i n Fig. 12.2 (ORNL Dwg D-AA-A-

40883).

The o r i g i n of t h e l i n e s venting t o t h e off-gas system a r e , i n

general, not shown i n Fig. 12.2, but on t h e flowsheets fbr t h e p a r t i c u l a r

i t e m s o f equipment involved. The off-gas l i n e from t h e f u e l c i r c u l a t i n g pump bowl, l i n e 522, i s 1/2-in. pipe but changes t o b i n . pipe a short distance from t h e pump and extends f o r about 68 ft inside t h e r e a c t o r c e l l t o provide a holdup volume o f about 6 f t3 and a residence t i m e of about one hour.

The l i n e continues

a s 1/2-in. pipe through t h e c e l l w a l l penetration and across t h e coolant d r a i n c e l l as 1/4-in. pipe t o an instrument box located i n t h e lower portion of t h e vent house.

I n t h i s box t h e flow passes through a hand

valve, V-522-A, a porous f i l t e r , and then a pressure c o n t r o l valve,

5 psig i n the PCV-522. This valve maintains a constant pressure of pump bowl by t h r o t t l i n g t h e sweep gas discharge. (The flow r a t e of t h e

363

VENT HOUSE

No. I

CWRC'IAL

:vu0

urvn

VENT nous

'I 9

izi1 MFILTRLTOU

r 'C

THIS DRAWING REFLECTS

'JFF GAS SYSTEM 8 CMAINMENT VENT. BATE

9-21-64

. I_-

..................

..-...

..-

.............

. .

................

l l l l . l " " 1 1 . w

.... ..... ---.

.----..-.-

". .

364

sweep gas i s l a r g e l y determined by t h e control valve and flow indicator

on t h e helium supply t o t h e pump bowl l i n e 516.) Provisions a r e made a t each s i d e of the pressure control valve f o r a future gas sampling s t a t i o n (valves V-522-B and V-522-C).

A d i f f e r e n t i a l pressure c e l l , P~I-556, i s

connected a t t h i s point and t o l i n e 557 downstream of t h e charcoal bed t o indicate the pressure drop due t o gas flow across t h e bed. O i l seeping past t h e lower r o t a r y shaft s e a l on t h e f u e l circulating pump flows through t h e 1/2-in. l i n e 524 t o outside t h e reactor c e l l and t o an o i l catch tank i n t h e s p e c i a l equipment room.

Line 524 i s shielded

with 1-1/2 i n . of lead inside t h e reactor c e l l t o protect t h e o i l from 8-

radiation damage.

The estimated o i l flow i s l e s s than 40 cc/day and

t h e accompanying helium flow i s about 0.07 liters/min.

The o i l

catch tank, waste o i l receiver and connecting piping a r e shown on t h e f u e l salt circulating system flowsheet, Fig. 5.3. scribed i n Section 5.4.1.5.

The equipment i s de-

The gas flow leaving t h e o i l catch tank,

stripped of o i l , passes through a sintered disc f i l t e r , a c a p i l l i a r y flow r e s t r i c t o r which l i m i t s t h e flow t o t h e above-mentioned 0.07 l i t e r s / min, and a c a p i l l i a r y flowmeter, Fa-524.

Line 524 continues as a 1/2-in.

sched 40 s t a i n l e s s s t e e l pipe t o the instrument box i n t h e vent house, I

where it changes t o 1/4-in. pipe.

The l i n e contains a branch connection

a t t h i s point leading t o a sampling valve, V-524.

After passing through

a check valve, CV-524, l i n e 524 joins the above-mentioned l i n e 522 downstream of the control valve, PCV-522. Continuing w i t h the discussion of t h e off-gas l i n e f r o m t h e f u e l pump bowl, l i n e 522, a 1/4-in. sched 40 pipe leads from PCV-522 i n t h e instrument box through t h e underground valve box t o t h e hold-up U-tubes i n t h e charcoal bed c e l l .

This water-cooled volume of about 7 ft3 pro-

vides an additional one hour of delay time and reduces t h e amount of heat emission that would be generated i n t h e charcoal beds.

The gas

leaves t h e holdup volume v i a l i n e 556, a 1/2-in. pipe connection t o t h e d i s t r i b u t i n g header for t h e main charcoal beds, l i n e 550.

Lines 620, 621, 622 and 623, each containing a hand valve, lead f'rom t h e off-gas d i s t r i b u t i n g header t o each o f t h e four sections of t h e main charcoal bed.

Each of t h e four sections contains about 22 t'f 3 of

activated charcoal.

Any two of t h e four sections a r e capable of handling 4.

e "I..-

....

. . . .

. . .

. . . . . . . . . .

~...I

......

I..-- --

365 t h e continuous off-gas flow of

4.25 liters/min.

The header, l i n e 550,

a l s o has a capped-tee connection for t h e possible f u t u r e addition of a helium recycle p l a n t . The gas discharge l i n e s *om

t h e f o u r sections of t h e charcoal bed,

l i n e s 624, 625, 626 and 627, each contain a hand valve i n a valve box adjacent t o t h e charcoal bed c e l l and has an extension t o bring t h e handle t o grade l e v e l .

The four l i n e s j o i n t o form l i n e 557, which has a tem-

porary vacuum connection, valve V-577-A, a check valve, CV-557-A, a hand block valve, V-577-B, and a r a d i a t i o n monitor, RIA-557.

On indication of

an abnormal l e v e l of a c t i v i t y t h i s monitor would cause closure of t h e block valve, HCV-557-C.

The off-gas l i n e from t h e a u x i l i a r y charcoal bed, l i n e

562, and t h e vent from t h e cooling s a l t d r a i n tank and t h e l u b r i c a t i n g o i l storage tanks, l i n e 560, connects t o l i n e 557 upstream of t h e r a d i a t i o n monitor. The off-gas vented from t h e fuel d r a i n tanks and t h e f l u s h s a l t tank flows through l i n e s 573, 575 and 577, respectively, t o form l i n e 561 leading t o t h e off-gas system.

Each of these t h r e e l i n e s contains a control

valve, as shown on t h e f u e l d r a i n tank system flowsheet, Fig. 6.1.

Line

561 i s contained within a 1 - i n . pipe i n i t s route from the drain tank c e l l , through t h e r e a c t o r c e l l and coolant d r a i n c e l l , t o t h e instrument box i n

t h e vent house.

It continues a s a 1/2-in. l i n e from t h i s box t o t h e valve

p i t and then t o t h e a u x i l i a r y charcoal bed i n t h e charcoal bed c e l l . During initial filling of t h e fuel system with s a l t it w i l l be

necessary t o vent a r e l a t i v e l y large volume of cover gas f r o m t h e system a t flow r a t e s of up t o about 1 cfm (STP). s

This can be accomplished through

l i n e 533, which connects t h e f u e l pump bowl vent, l i n e 522, with t h e COP-

nection t o t h e a u x i l i a r y charcoal bed, l i n e $1.

This 1/2-in. cross con-

nection contains a check valve t o prevent back flow, CV-533, and a control valve, HCV-533. The gas vented f’romthe sampler-enricher through l i n e 542 i s shown on t h e fuel system process flowsheet, Fig. 5.3.

w x

This 1/2-in. pipe j o i n s l i n e

561 i n s i d e t h e r e a c t o r c e l l and is vented through t h e a u x i l i a r y charcoal bed along with t h e gases from t h e d r a i n tanks, e t c . The 1-1/2-in. c e l l evacuation connection, l i n e 565, leading from t h e discharge of t h e blowers i n t h e s p e c i a l equipment room t o t h e vent house,

366 f i l t e r p i t and stack, i s cross connected through l i n e 5 7 1 t o l i n e 561. (Line 565 w i l l be described subsequently.)

This connection, which con-

t a i n s a check valve, CV-571, and a hand valve V-571, allows t h e r e a c t o r c e l l t o be evacuated through t h e a u x i l i a r y charcoal bed i f t h e r e has been

a r e l e a s e of a c t i v i t y within t h e c e l l . The 1/2-in. effluent from t h e a u x i l i a r y charcoal bed flows through l i n e 562, which joins l i n e 557 and 565 i n t h e vent house upstream of t h e r a d i a t i o n monitor and block valve, f o r discharge through t h e f i l t e r s and up t h e stack.

Before making the juncture, l i n e 562 contains a hand valve

i n t h e valve p i t a t t h e charcoal bed c e l l , v-562-~, a check valve i n t h e vent house, CV-562,

followed by another hand valve v-562-c.

Upstream of

t h e check valve, a valved connection, V-562-B, i s provided a s a temporary vacuum connection.

The coolant d r a i n tank, CDT, i s vented t o t h e off-gas system through l i n e 527, and then through l i n e 547 and control valve HCV-547, t o j o i n l i n e 560.

These l i n e s , and those described i n t h e next two paragraphs,

a r e shown on t h e coolant system flowsheet, Fig. 8.1. The coolant s a l t c i r c u l a t i n g pump, CP, has i t s bowl vented through l i n e 528.

This 1/2-in. pipe i s provided with a porous f i l t e r ahead of

t h e control valve, PCV-528. This control valve has a maximum capacity of

0.623 liters/min.

It i s followed downstream by a check valve, cv-528

(located i n t h e vent house), and a r a d i a t i o n monitor, RIA-528. The check valve prevents backflow from l i n e 560.

The monitor provides an e a r l y warn-

ing i n event t h e coolant s a l t c i r c u l a t i n g system becomes contaminated through a l e a k i n t h e main heat exchanger.

It a l s o indicates whether a

r a d i a t i o n alarm by t h e monitor on l i n e 557 i s a t t r i b u t a b l e t o such a heat exchanger leak o r t o contaminants from other p o t e n t i a l sources which flow p a s t t h i s monitor. The gas space o f t h e coolant s a l t d r a i n tank and t h e vapor space i n t h e coolant salt c i r c u l a t i n g pump bowl have t h e pressure equalized by being interconnected through l i n e 536 and HCV-536, which j o i n s t h e above-mentioned d r a i n tank vent, l i n e s 527 and 917, with t h e pump bowl vent, l i n e 528.

!The

connection t o l i n e 528 i s upstream of t h e f i l t e r i n order t o bypass it and t h e control valve, PCV-528, when t h e system i s being f i l l e d with s a l t .

bjl P

367

w e

a d d i t i o n a l 1/2-in. cross connection i s made between these two l i n e s through l i n e 527 and HCV-527, t o permit t h e rapid exchange of cover gas for quick drainage of t h e coolant s a l t from t h e c i r c u l a t i n g system. Line 534 from t h e vapor space of t h e coolant c i r c u l a t i n g pump o i l supply tank, OT-2, i s shown on t h e o i l system flowsheet, Fig. 5.25. (ORNL

D-AA-A-40885)

This l i n e contains a hand valve, V-534-A, and a pressure

control valve, PCV-51O-A2.

This control valve i s set t o open a t a s l i g h t l y

higher pressure than t h e normal operating pressure i n t h e tank (- 10 p s i g ) , and thus serves t o p r o t e c t t h e tank from a pressure buildup due t o a leaky cover-gas supply valve, PCV-5lO-Al.

The c o n t r o l valve i s followed by a

check valve, CV-534, a hand valve, V-534-B, and two capped sample t a p s . These t a p s can be used t o check f o r leakage through t h e check valve.

The

hand valves on each s i d e of t h e control and check valves permit i s o l a t i o n

f o r maintenance purposes. o i l supply tank, OT-1,

The vented gas from t h e f u e l c i r c u l a t i n g pump

i s s i m i l a r l y equipped, as shown on t h e same flow-

sheet, and j o i n s l i n e '334 downstream of t h e valve, V-534-B, f o r routing across t h e coolant c e l l t o combine w i t h t h e aforementioned l i n e '327.

In summary, l i n e 560 vents off-gas f'rom t h e coolant d r a i n tank, t h e coolant pump bowl, t h e coolant pump o i l catch tank, and t h e f i e 1 and coolant The vented gas flows p a s t a r a d i a t i o n

pump l u b r i c a t i n g o i l supply tanks.

monitor-controlled block valve, HCV-5574, t o t h e f i l t e r p i t f o r subsequent d i l u t i o n and discharge up t h e off-gas stack. A p o r t i o n o f t h e gas discharged by t h e component cooling system

blowers, described i n Section 16, i s diverted through l i n e 565 t o t h e o f f gas system t o maintain t h e r e a c t o r and d r a i n tank c e l l s below atmospheric pressure.

(The point where l i n e 563 branches f'rom l i n e 917 is shown on t h e

fie1 system flowsheet, Fig. 5.3.

The remainder o f l i n e $5

off-gas system flowsheet, Fig. 12.2.)

i s shown on t h e

Line $5 passes from t h e s p e c i a l

equipment roan through t h e coolant d r a i n c e l l t o t h e vent house, where it contains a r a d i a t i o n monitor, RIA-$5.

A 3/4-in. branch connection down-

stream of t h e monitor, l i n e 566, permits returning 20 t o 100 cfm ( S W ) of t h e gas back t o t h e component cooling system v i a lines 922 and 930. Line 'rt

W a

566 contains a check valve, cv-566, t o prevent backflow, and a hand valve, V-566. The remainder of t h e c e l l atmosphere gas (3% 02, 95% N2) flows through a control block valve, which receives i t s s i g n a l from t h e r a d i a t i o n monitor.

368 The reactor c e l l can be evacuated i n t e r m i t t e n t l y a t

100 cfm (STP)

through valve V-565-c and check valve CV-565, o r by a continuous small flow of about 1 liter/min through a bypass around V-565, l i n e 569.

This

1/4-in. bypass l i n e contains a ceramic f i l t e r , two hand valves, V-569-A

V-569-B, a check valve CV-569, and a wet t e s t meter t o measure flow, F~I-369. Sample t a p s on l i n e 565 and on l i n e 569, w i t h valves V-565-B and V-569-~, respectively, allow i n s t a l l a t i o n of a sample bomb between t h e two p o i n t s . The aforementioned l i n e 557 connects t o l i n e 565 i n t h e vent house before it continues t o t h e f i l t e r p i t .

12.3 Holdup Volumes The highly radioactive gas *om

t h e f u e l c i r c u l a t i n g pump bowl i s

held up f o r about 1-1/2 hrs t o allow t h e short-lived fission-product isotopes t o decay and thereby reduce t h e heat generated i n t h e charcoal bed. Based on an average off-gas temperature i n s i d e t h e r e a c t o r c e l l piping o f WOOF, a s p e c i f i c a c t i v i t y i n t h e gas of 0.15 watts/cc,

ambient c e l l temperature of 1P0F, and an average temperature of 100°F f o r t h e gas i n t h e charcoal bed holdup volume, t h e t o t a l holdup volume requirement w a s estimated t o be about 13 f t 3 i s one hour. 148

. The minimum holdup time

A t design flow r a t e s , 13 ft3 o f holdup volume provides

1-1/2 h r s of residence time.

About 6 f't3 of t h e holdup volume i s provided i n s i d e t h e r e a c t o r c e l l upstream o f t h e pressure c o n t r o l valve PCV-522.

This volume not only

allows for t h e decay of fission-product gases and d i s s i p a t i o n o f heat t o t h e c e l l atmosphere gas, but a c t s as a surge volume t o provide f o r b e t t e r a c t i o n of t h e pressure control valve. 148

The holdup volume c o n s i s t s of

68 ft of 4 i n . , 304 s t a i n l e s s s t e e l , sched 40 pipe.

The 4 i n . pipe c i r c l e s

t h e c e l l wall counter clockwise a t t h e 831-1/2 f't elevation u n t i l reaching t h e north s i d e of t h e c e l l where it doubles back i n a f l a t "S" bend, dropping it t o t h e 829-1/2 f't elevation.

The pipe continues downstream

a t t h i s elevation and bends up t o terminate a t a pipe reducer where t h e l i n e s i z e again becomes 1/2 i n . t o leave t h e r e a c t o r c e l l through t h e w a l l penetration.

On t h e other s i d e of t h e wall t h e l i n e continues as 1/4-in.

369

sched 40 pipe contained within 3/4-in.

sched 40 pipe.

The 3/4-in. pipe

i s sealed a t t h e c e l l wall but open t o t h e instrument box i n t h e vent

house. Additional holdup volume i s provided i n t h e charcoal bed c e l l i n t h e form o f s i x 19.8-ft lengths of 3-in. sched 10, 304 s t a i n l e s s s t e e l , pipe connected i n t h r e e v e r t i c a l U-tube configurations, with 180' bottom and each l e g capped a t t h e top.

bends a t t h e

The U-tubes a r e connected i n s e r i e s

by 1/2-in. piping t o give a t o t a l volume of about 7 n3. (See ORNL Dwg.

E-JJ-A-41519)

The U-tubes a r e immersed i n water f o r cooling, a s i s t h e

other equipment i n t h e charcoal bed c e l l .

12.4 Off-Gas Charcoal Beds 12.4.1 Main Charcoal Beds The radioactive fission-product gases i n t h e off-gas stream have an average residence time on t h e activated charcoal o f about 9 days for t h e xenon and 7-l/2 days f o r t h e krypton. The charcoal beds were designed on t h e b a s i s of a 10-Mw r e a c t o r power l e v e l , assumption of 3-gpm complete removal of fission-product gases fiom f b e l s a l t i n t h e pump bowl and a 2.3 f't3 of gas space i n t h e pump bowl a t 1200'F.

The maximum r a t e of helium purge gas flow was taken a s

6,000 l i t e r s / 2 4 h r s (STP). The m i n i m u m holdup time f o r t h e xenon w a s fixed a t 9 days and the corresponding time for t h e krypton a s 7-l/2 days. 0

The maximum allowable charcoal bed temperature was assumed t o be 250 F and t h e maximum cooling water temperature a s about 85 F. 148 Flow r a t e s t o t h e charcoal bed were calculated by t h e method o f Stevenson,149 using nuclear data from Blomeke and Todd. lW ing IBM 7090 program.

Data sheets were prepared using an e x i s t -

The a c t i v i t y of t h e xenon and krypton a s a

function of time a f t e r leaving t h e pump bowl, t h e charcoal bed temperature f o r various flow r a t e s , and t h e a c t i v i t y leaving t h e off-gas stack a s a function of holdup time, a r e shown i n Figs. 12.3, 12.4, and 12.5. o u t l i n e of t h e calculation procedures i s given i n Ref. 148.)

(An

The atom

flow r a t e s f o r a minimum flow of 1,000 l i t e r s / d a y and maximum flow of

bd E

5,000 l i t e r s / d a y , a r e given i n Table 12.2.

. 370 Unclassified ORNL ISWG 64-8836

Note: A t 10 Mw, 50 glpn By-Pass Flow and 5,000 l i t e r s / d a y Sweep Gas Flow

lo13 0

2 3 4 Time After Leaving

Figure 12.3.

Bowl, Hrs

Activlty of Fission-Product Isotopes of Xenon and Krypton in Pump B o w l O f f - G a s .

371

Unclassified O m DWG 64-8837

180

Nor€: THESE DATA ARE SPECIFIC FOR FOLLOWING CONDITIONS 170

POWER 10 MWT HRT GEOMETRY SECTION I - 40'-1/2" SECTION II 40'-1" SECTION E 40'-2" SECTION 1p 40'-6" PRE-BED HOLDUP - 2 hrs

160

150 0

5 140 c

a CL

130

5 W

I-

120

>i 110

IO0

m 90 4 c

0.5

i.o

1.5

2 .o

2.5

3.0

FLOW RATE, liters/min

Fig. 12.4. Estimated Charcoal Bed Temperatures os Function of Flow Rote Through the Bed.

. 1

372 Unclassified ORNL DWG 64-8838

I Note:

Kr88

Reactor m e r = 10 Mw stack Flow = 20,Ooo C h

\ ..

\ \

Figure 12.5.

70 Hold-up "he,

80 Days

Concentration of Xenon and Krypton a t OfY-Gas Stack Outlet.

100

373

Atoms per second

Isotope

...

c I C

1,000 lit er/24 -hr Purge Rate

5,000 liter/24-hr Purge Rate

83%

1.15 x i o15

1.35 x 1015

8%i-

4.15

4.46

85*

0 -93

87,

5.95

7.28

88Kr

9.53

10 -73

’31”Xe

.ow

0 -093

’33mXe

0.50

’33~e

20 .o

20.10

’3 %e

18.1

18.82

. 374

cill There a r e two charcoal beds connected i n p a r a l l e l , and each i s capable of handling t h e fill off-gas load of t h e MSRF:.

Each bed con-

sists of two v e r t i c a l sections containing, first, 80 f't of 1/2-in. sched 10 pipe, 80 ft of 3-in. sched 10 pipe, and then 80 f't of 6-in. sched 10 pipe.

The smaller pipe s i z e s a r e used on t h e i n l e t end t o pro-

vide more surface-to-volume r a t i o f o r t h e d i s s i p a t i o n of heat t o t h e s u r rounding water.

The e f f e c t of t h e pipe s i z e on t h e bed temperature i n

t h e first section i s shown i n Fig. 12.6. v e r t i c a l sections i s about 20 ft. 41724)

The o v e r a l l height o f t h e

(See ORNL Dwg E-JJ-B-41519 through

A l l piping is 304 s t a i n l e s s s t e e l and t h e system i s o f a l l -

welded construction with each j o i n t X-rayed a f t e r f a b r i c a t i o n . The t o t a l volume of each bed (two s e c t i o n s ) i s 44 ft3, requiring about 1,455 lbs of charcoal f o r f i l l i n g . *

The charcoal i s P i t t s b u r g

Q-pe PGB 6 x 16, a type that has proven s a t i s f a c t o r y i n s t a t i c and dynamic absorption t e s t s . 152 2 . 1 liters/min.

Each section has a m a x i m flow r a t e of

The c e n t e r l i n e temperatures calculated for several flow

r a t e s are shown i n Fig. 12.4.

The temperatures a r e measured by a thermo-

couple a t t h e i n l e t o f each d i f f e r e n t pipe s i z e i n each ,section.

The

maximum pressure drop i s estimated t o be 1.5 p s i . 12.4.2

Auxiliarv Charcoal Bed

Since t h e a u x i l i a r y charcoal bed i s used i n t e r m i t t e n t l y , t h e r e i s enough time between periods of use f o r fission-products t o decay t o l e v e l s where a breakthrough o f a c t i v i t y from t h e bed i s highly i m probable. 148

Further, t h e s p e c i f i c a c t i v i t y of t h e gas passing through

t h e bed i s low enough t o make heat r e l e a s e i n t h e bed only a minor consideration. The a u x i l i a r y bed i s designed t o contain 140 f t 3 o f gas (STP). maximum design flow rate i s 1 c~

The

(STP).

The bed consists of two vertical U-tube sections of 6-in. sched 10,

304 s t a i n l e s s s t e e l pipe. by short-radius 180'

The legs a r e about 19.21 f't long connected

bends a t t h e bottom and with 1/2-in. pipe connect-

ing t h e capped tops i n s e r i e s .

The t o t a l amount of charcoal i n both

*Based on a bulk d e n s i t y for t h e charcoal of 0.53 g r / c c .

. 3 75

Unclassified ORNL DWG 64-8839

Inside Pipe Diameter, In. Power = 10 Elw Bypass Stream Flow = 50 gpm Sweep Gas Flow = 4.2 liters/min (total) 1.05 liters/min (bed)

Pre-bed Holdup = 2 hrs Figure 12.6.

Maximm Estimated Temperature i n First Section of Charcoal Bed vs Pipe Diameter.

376 sections i s 9 3 l b s and i s of t h e type used i n t h e main charcoal beds.

&id %

A 3-in. thickness of s t a i n l e s s s t e e l wool a t t h e top of t h e l e g pre-

vents movement of t h e charcoal.

The i n l e t temperature t o each section

i s measured by a thermocouple i n a well on t h e c e n t e r l i n e of t h e p i p e . Fabrication d e t a i l s a r e shown on ORNL Dwg E-JJ-B-41319

through 41324.

12.5 Piping, Valves and F i l t e r s

12.5.1 Piping A l l piping inside t h e reactor and drain tank c e l l s i s seamless 304 s t a i n l e s s s t e e l , sched 40.

I n most cases t h i s pipe w a l l thickness was

not governed by i n t e r n a l pressure considerations but was selected t o provide resistance t o mechanical damage during i n s t a l l a t i o n and maintenance of the reactor.

The piping outside t h e containment areas i s sched 40

carbon s t e e l .

F i t t i n g s used with t h e s t a i n l e s s s t e e l piping a r e b u t t -

welded.

Some valves, however, a r e socket-welded, o r flanged, as may be

noted i n t h e off-gas system valve tabulations, Tables 12.3, 12.4, and 12.5.

The carbon s t e e l piping i s e i t h e r screwed o r welded, depending

upon t h e a c c e s s i b i l i t y f o r inspection and maintenance and upon t h e seriousness of the s i t u a t i o n developing *om

a possible leak.

The main off-gas pipe, l i n e 522, and t h e a u x i l i a r y off-gas pipe, l i n e 361, a r e each contained within another pipe i n t h e run between t h e containment v e s s e l wall and t h e valve box i n t h e vent house.

Both inner

and outer pipes a r e seamless 304 s t a i n l e s s s t e e l , sched 40, and a l l j o i n t s a r e butt-welded and X-ray inspected.

The annular space i s pres-

sure-tight, sealed a t t h e r e a c t o r c e l l wall and open t o t h e instrument box atmosphere.

The s l i g h t vacuum i n t h e box produced by t h e suction

of t h e stack fans provides assurance that any out-leakage of radioactive gases w i l l be carried t o t h e f i l t e r s and t h e off-gas stack.

The monitors

on t h e l i n e s leading t o t h e f i l t e r s would d e t e c t any r a d i o a c t i v i t y escaping through such leaks.

12.3.2 Valves The air-operated valves i n t h e off-gas system a r e of t h e flanged type.

A l l others inside t h e containment vessel were welded i n t o t h e

. piping e i t h e r by b u t t o r socket-type welds.

The valves i n t h e off-gas

system a r e l i s t e d i n Tables 12.3, 12.4, and 12.5. Hand valves i n piping which must be shielded, such as those i n t h e underground valve box a t t h e charcoal bed c e l l , have s p e c i a l extension handles, as shown on ORNL Dwg D-JJ-A-56255. 12.5.3

Filters

12.5.3.1

Porous Metal F i l t e r i n Line 522.

- A f i l t e r i s provided

i n l i n e 522 upstream of t h e control valve, PCV-522, t o p r o t e c t it from possible damage o r plugging. _. L

The f i l t e r housing is a section o f 1-1/2-in.

304 s t a i n l e s s s t e e l pipe about 20 i n . long with a cap welded on t h e bottom and a r i n g - j o i n t flange a t t h e top, a s shown i n Fig. 12.7.

The f i l t e r

element i s a f l u t e d porous metal cylinder 1-1/32-in. qdiam x 17-in. long. 2 The pore diameter i s 40 microns and t h e surface area i s about 6 i n . / i n . of length.

The f i l t e r element i s screwed t o a 1/2-in. coupling welded

t o t h e 1-1/2-in. x 1/2-in. reducing flange which e f f e c t s t h e top closure. The 1/2-in. i n l e t pipe, l i n e 322, enters t h e s i d e of t h e f i l t e r housing. The 1/2-in. o u t l e t pipe connects t h e top flange t o t h e control valve HCV-522.

The pressure l o s s due t o flow through the f i l t e r i s negligible

a t t h e maximum design flow r a t e of 4.2 liters/min.

. * L

12.5.3.2

Porous Metal F i l t e r s i n Lines 524, 526, 528 and 569.

- The

f i l t e r s i n l i n e s 524 and 526 a r e upstream of c a p i l l a r y flow r e s t r i c t o r s t o provide protection against plugging.

stream of t h e control valve, HCV-528.

The f i l t e r i n l i n e 528 i s upLine 569 leads t o a sampling

s t a t i o n and t h e f i l t e r i s i n s t a l l e d upstream of the sampling valve,

V-569-D.

The four f i l t e r s a r e Nupro F i l t e r s , Type F, No. SS-P4-60, with

modified 30,000-psi Autoclave connections.

The body of each f i l t e r i s

3/4-in. diam x 3 i n . long (before modification) and contains a porous 2 metal thimble with a surface area o f 1.386 i n The nominal pore diameter

i s 60 microns.

The body has a threaded closure with a metal O-ring s e a l .

The u n i t s a r e constructed of 316 s t a i n l e s s s t e e l .

The pressure loss due

t o flow a t design conditions of 1 liter/min i s negligible.

378 Table 12.3

Off-Gas System A i r a p e r a t e d Valves

Valve Number

MSRE Specification

Fail Position

PCV- 510-A2

Open

0.0035

Description 1/2-in. NPS, 1-in. integral ring joint, through b o l t s

PCV-513 -A2

Open

0.0035

PCV-522-A

Open

0.02

HCV-527 -A1

Open

3.5

PCV-528-A

Open

0.003

HCV-533-Al

Open

3.5

HCV- 536-A1

Open

3.5

HCV- 547 -Al

Open

3.5

HCV-577 -C

Closed

3.0

HCV-573-Al

open

3.5

HCV- 57 5-A1

Open

3-5

HCV-577-Al

Open

3.5

HCV- 565-Al

Closed 21.0

Bellows-sealed, 347 o r 304 s t a i n l e s s s t e e l . 11

1-1/2-in. NPS, weld end, Teflon-packed bonnet, Teflon s e a t , 304 s t a i n l e s s steel.

379 Table 12.4 Off-Gas System Check Valves Valve Number

Spec. No.

Description

524

cvs-1

Circle Seal - Dwg. 705

528

3/8" Autoclave connections

562

cvs-1 cvs-1 cvs-1 cvs-1 cvs-1 cvs-1 cvs-1

573

cvs-5

775

cvs-5

577

CVS-5

565

CVS-6B

Circle Seal, NO. 258-12~~ 1-1/2-in. pipe, threaded, brass

566

cvs-6A

Circle Seal, No. 259-T1-6PP, 3/4-in. pipe threads, sealwelded, 300 stainless steel

569

cvs-7

Nupro No. 4 C4, 1/4-in. pipe threads, brass

534 535

557A 557B 560 f

Soft seat (Teflon)

Spring-loaded 300 series stainless steel 11

380 Table 12.5 O f f - G a s System Hand Valves Valve Nwber

534A 534B 53% 535B 557B 560

Specificat ion

Hvs-1

HvS -u

562c 52% 525B 529 720~ 720~ 720c 770

Description Hoke, TY 440, socket-weld t o 1/4-in. OD tube, bellowssealed, 316 s t a i n l e s s s t e e l Hoke, TY 440, socket-weld t o 3/8-in. OD tube, bellowssealed, 316 s t a i n l e s s s t e e l Crane, socket weld, 1/2-in.

NPS, bellows -sealed, Monel SMD

Hvs-2

Hoke, LY 473, socket weld, 112-in. NPS, bellows-sealed, 316 s t a i n l e s s s t e e l

Hvs-3

Same as HVS-2.

620 621 622 623 624 625 626 627

Hvs -4

Fulton Sylphon 303), 1/4-in. NPS, b u t t weld, bellows-sealed, 347 s t a i n less steel.

590 591 56% 5653 566

SSD

557A 557c 562 52a 52= 522C 524

561 56211

571

. SMD

SMD

Crane, socket weld, 1/2-in. NPS, stainless s t e e l . Crane, socket weld, 1-1/2-in.

NPS, bellows-sealed, Monel. Crane, socket weld, 3/4-in.

NPS, bellows -sealed, Monel

565B 569

Hoke, RB 271, bar stock needle valve, packed, threaded, 1/4-in. NPS.

569B 56%

Hoke, RB 281, bar stock metering valve, packed: threaded, 1/4-in. NPS.

381 Unclassified

O m DWG 64-8840

Purolstor SC-20 50lnicron Pore S i z e Filter Element !Qpe 1 Bottam c Type 4 (1/2-in. Top Cap.

. W

Figure 12.7.

Porous Metal Filter i n Off-Gas Line 522.

383

13. COmTAIhlMEmT -1LATION

SYSTEM

The containment ventilation system provides a continuous and con-

trolled flow of air through all areas where radioactive or beryllium contamination i s likely t o occur. Such areas include the high-bay area, the reactor and drain tank c e l l s (during maintenance), the s i x smaller special-purpose cells, the electric service areas, transmitter mom, service tunnel, special equipment room, coolant cell, vent house, and charcoal bed cell. The general pattern of the air flow i s from the less hazardous t o the potentially more hazardous areas and then t o exhaust ducts where it

i s passed through absolute f i l t e r s and monitored for radioactivity before release. In a broad sense, the air flow i s from the north end of Building 7503 toward the exhaust stack at the south end. The ventilated areas are operated at l e s s than atmospheric pressure t o assure that leakage of air i s i n w a r d .

With but few exceptions, such a s in the change room, the concern i s for maintaining this negative pressure rather than for ventilating at an established flow rate. To accomplish this, particularly when the ventilation rate must be increased t o certain ereas during abnormal or maintenance conditions, it lnay be necessaryto shargly decrease the air flow into certain other areas.

13.1 Iayout and General Description The containment ventilation system u t i l i z e s either of two 21,OOO-cf’m (nominal capacity) centrif’ugal fans located at the base of the 100-fthigh stack t o induce alr flow through the various containment areas i n and w a c e n t t o Building 7503. The estimated rates of air removal from these areas during normal reactor operation are sham i n Table 13.1. As shown i n the simplified air flow diagram, Fig. 13.1, the bulk of the air (14,000 t o l7,OOO cfm) enters the main building at the northwest comer through an i n l e t air f i l t e r house. I n addition t o dust f i l t e r s , t h i s house contains steam-heated c o i l s for warming the intake air during the winter months.

A bypass -per

in the house w a l l assures an air

supply even though the f i l t e r s become excessively clogged. Another counter-balanced bypass damper prevents the differential pressure between

384

Table 13.1.

Estimated Containment Ventilation System Air Flow Rates During Normal Reactor Operation. (Cfd

Through supply-air filter house

Through change room Leaving high-bay at southeast corner Leaving liquid-waste storage tank Through liquid-waste cell Through remote maintenance pump cell Through decontamination cell Through equipment storage cell

- 17,000 100 - 1000 12,000 - 15,ooo 14,000

- 400 200 - 1500 200

200 200

Through fuel processing cell

200

Through spare cell Leaving south electrical service areaa

200

Leaving charcoal beds cell Leaving service tunnel

- 1500

- 400

- 400 400 - 600

Leaving reactor and drain tank cells Ieaving coolant cell Uaving special equipment room Through vent house

- 100

- 1200 200 - 400 800

200

400

- 400

- 100

- 600

aAir flow is from the transmitter room to the north electric service area, and then to the south service area (which includes the west tunnel).

Unclassified

ORNL DWG 64-8841

FILTERS

STACK

i Fig. 13.4. Schematic of Air F l o w Diagram Containment Ventilation System.

t h e atmosphere and t h e high-bay a r e a from becoming high enough t o collapse t h e sheet-metal l i n e r .

The a i r e n t e r s t h e high bay between columns 2 and

3 a t t h e 874-ft elevation.

About 1000 cf'm of a i r i s a l s o drawn i n t o t h e

high-bay a r e a through t h e change, or locker, room l o c a t e d at t h e same level. Exhaust ducts leading t o t h e main intake ducts f o r t h e stack fans withdraw a i r from each of t h e six s m a l l c e l l s l o c a t e d beneath t h e opera t i n g f l o o r level,* causing a i r t o be drawn from t h e high-bay a r e a down through t h e openings between t h e concrete roof blocks covering t h e s e cells.

The v e n t i l a t i o n rate f o r each c e l l v a r i e s from 200 t o 1500 cf'm,

depending on t h e exhaust-duct damper s e t t i n g s .

A blower on t h e exhaust

from t h e liquid-waste storage tank maintains it a t a lower pressure than t h a t of t h e c e l l .

Another exhaust duct p u l l s 400 t o 600 cfm of a i r from 'r

t h e e l e c t r i c service a r e a t r a n s m i t t e r room, west tunnel, e t c . , t h e a i r having reached t h e s e rooms from t h e high-bay area through various stairways, passages, e t c .

The bulk of t h e a i r from t h e high-bay area (12,000

t o 15,000 cfm) i s normally exhausted a t t h e operating f l o o r l e v e l through two openings t h a t f l a n k t h e sampler-enricher s t a t i o n area6 A hood above t h e samplers a l s o provides v e n t i l a t i o n during sampling. The coolant c e l l i s maintained a t a lower pressure than t h e high-bay area.

A i r i s exhausted from t h e c e l l through an opening i n t h e south w a l l

at about t h e 861-ft elevation. general leakage, e t c . ,

A i r a l s o e n t e r s t h e coolant c e l l through

from outside t h e building and i s only p a r t i a l l y

drawn from t h e high-bay area.

A i r i s a l s o exhausted from t h e s m a l l vent house l o c a t e d a t t h e south end of t h e main building.

A i r e n t e r s t h e house through a f i l t e r i n a

small opening i n t h e w a l l and leaves through a small duct leading t o t h e main intake duct f o r t h e stack fans. During maintenance operations i n t h e r e a c t o r o r d r a i n tank c e l l s , a i r can be exhausted from t h e c e l l s t o cause a downflow of a i r through t h e openings where concrete roof plugs have been removed.

This p o s i t i v e

*Liquid-waste c e l l , remote maintenance pump c e l l , decontamination c e l l , equipment storage c e l l , f u e l processing c e l l , and t h e spare c e l l .

* I

387

6d n

downward movement of 100 f@n, or more, materirtlly aids i n preventing escape of airborne contaminants into occupied building areas. To accomplish this circulation, l5,OOO cfm of air i s withdrawn through a 3O-in.-diam, shadow-shielded opening at the bottom of the southwestern sector of the ii The air then flows through a %-in,reactor-cell conts.lnmant vessel, diam carbon s t e e l duct across the coolant drain c e l l and through the special equiprment room t o a valve station in the service tunnel containing two 3O-in.-diam motor-operated butterfly valves in series. The valves are closed during reactor operation and are opened only when roof plugs have \ been removed for maintenance and c e l l ventilation i s required, (A =-in. sched-b pipe takes off the P-in.-diam duct upstream from the butterfly valves and leads t o the reactor containment vessel vapor-pressure suppression system, as described in Section 17.) The 3O-in.-diam duct continues underground t o the vicinity of the f i l t e r pit, where it turns t o join the main 36-in.-dim duct leading t o the p i t . The two motor-driven fans and the 100-ft s t e e l stack f o r discharge of the air are located about U O ft south of Building 7503. (Off-gas from the charcoal adsorber beds i s also vented through the f i l t e r p i t and stack, see Section 12.) The containment ventilation system is provided w i t h numerous manually positioned d&tnperst o adjust the air flow. Differential-pressure c e l l s indicate direction of air flow, f i l t e r resistances, etc, In general, a l l components i n the system are commercially available.

The general layout of the containment ventilating system and key t o

drawings i s shown on ORNL drawings D-KK-A-41024, D-KK-D-kll13 13.2

D-ICK-A-41062,

and

Flowsheet

The flowsheet f o r the containment ventilation system i s shown in

Fig, 12.2. Air i s drawn into the inlet-air f i l t e r house at a rate of about l5,OOO cfm through llFiberglasll dust f i l t e r s having a pressure drop (when

! 1

W e point of l a r e s t elevation i n the 30-in. line drains through a 3/4-in1. pipe (no line number) t o the reactor contairment-vesse1 sump.

388

A bypass damper in the side of the clean) of about 0.028 in. of %O. house is counter-weighted to open if the negative pressure exceeds 0.35 in. of %O, and assures an air supply in event the filters become excessively dirty. After passing over a stem-heated extended-surface heating coil, the air is delivered to the high-bay area of the main building through a 4.0 x 60-in. insulated duct, line 953. A manually set -per located in this line Just above the filter house permits adjustment of the negative pressure in the high-bay area to 0.1to 0.3 in. of €$O. A counter-weighted dam,per in the 30 x @-in. bypass duct, line

954, opens a t a negative pressure of 0.45.in.

of H20 t o p r o t e c t t h e high-

bay liner from excessively low pressures. Air is also drawn into the high-bay area through the change room at an estimated rate of about

lo00 cfm. Air is exhausted from the liquid-waste cell, the remote maintenance pump cell, the decontamination cell, the equipment storage cell, the fuel processing cell, and the spare cell, by individual 32 x 12-in. ducts, lines 94.0 through 944. Each duct contains manually set dmpers to balance the air flow and differential-pressure cells to indicate the cell pressure. !%e estimated ventilation rate for most cells is about 200 cfh during normal operation. An individual cell may have a ventilation rate as high as &l5OO cfb during maintenance in that cell. Air finds its way into these six cells from the high-bay area through the openings between the concrete blocks covering the cells. Line 944 exhausts air from both the liquid-waste cell and the remote maintenance cell. Gases vented from the waste storage tank in the liquid-waste cell are exhausted through a 6-in. pipe, line 948, to a blower in the adjoining remote maintenance pump cell; this location f o r the blower makes it more accessible for maintenance. %e energy input of the 180 cf’m blower is sufficient only to overcome the pressure loss due to flow in the 6-in. pipe and permit discharge directly into the exhaust duct, line 945, without backflow into the remote maintenance cell. Air in this cell, which is open to the high-bay area a -or portion of the time, is exhausted through line 945. It is to be noted that the gases vented from the waste storage tank may at times be radioactive, such as when the caustic scrubber in the fie1 reprocessing system is vented, or

u (I

possibly when the air-operated (,26 c f i ) j e t pumps are used t o remove water from the drain tank c e l l and reactor coptainment-vessel sumps. The control system interlocks would cause the waste blower t o stop on a loss of flow t o the stack fans. The inleakage through the seals in the sealed high-bay area i s estimated t o be less than 1000 cfm. Air from the south electric service area is exhausted through a 12 x 32-in. duct, line 937, at a rate of about 600 cfm. Some of this air i s drawn i n through the transmitter room and from outside, but most of the flow i s from the 8404%level t o the north e l e c t r i c service area and then t o the south electric service area. A packaged air conditioner removes heat from the transmitter room i n a closed air circulation cycle. The six 12 x 12-in. ducts described above have manual dampers at the 853-ft elevation on the east w a l l of the high-bay area. They then combine in a manifold t o form a 20 x 20-in. duct, line 936, then t o a 26-in. duct, line 928, which runs south at the 873-ft elevation above the roof of the office mea. The bulk of the air is drawn from the high-bay area through an intake opening located at the southeast corner. About l5,OOO cf'm i s removed through the 33-in.-diam duct, line 935. Two openings are provided f o r exhausting air into this line. A 9-in. side connection d r a w s air from the exhaust hood at the sampler-enricher station. Af'ter the 26-in.-di= duct, Une 928, and the 33-in.-diam duct, line 935, join above the roof of' the office area, t h e duct size becomes 36 in. in diameter a d continues as line 927 above ground t o the entrance of the f i l t e r p i t . A motorized damper, HOT-935, permits regulation of the t o t a l air flow. Air is exhausted from the coolant c e l l through a 16 x &in. duct, line 934, w i t h the intake opening at the 8554% elevation. %is duct at the 862-ft elevation. h o t h e r 16 x contains a motor-operated -per 16-in. duct, line 933, exhausts air from the c o o m t c e l l at the 862-ft elevation. Either one, o r both, can be used f o r venting the coolant cell. Duping maintenance the flow rate may be about l!jOO cfip. The nearby vent house i s ventilated by &m€ng about 250 cfmthrough a f i l t e r in the w a l l of the vent house and exhausting it through line 959. !Bis Il-in.-diam

390 -

duct connects t o line 933 on the outside south w a l l of the main building. A manually operated damper i n line 959 permits adjustment of the air flow t o about 250 cfm. The charcoal bed i s ventilated by exhausting air through l i n e 950. A i r from the instrument box, w h i c h contains the valving f o r the charcoalbed gas lines, i s w i t h d r a w n through l i n e 951. These two lines combine,

and a s line 950, join the 18 x 18-in. duct, line 932. As mentioned above, line 932 joins the main duct leading t o the f i l t e r p i t , line 927. The reactor and drain tank c e l l s norxnally operate at about 2.0 p s i . below atmospheric pressure and with an atmosphere of about 95$ N2 and 5$ 02. During maintenance operations, when concrete roof plugs are removed, the two butterfly valves are opened i n line 930, t o exhaust the c e l l s and p u l l air from the high-bay area dam through the opening. For openings of 150 f t2 and smaller, the downward velocity w i l l exceed 100 fpm. Under most maintenance circumstances, the openings w i l l be small and the bulk

of the air leaving the high-bay containment area w i l l continue t o be withdrawn through line 935 at the southwest corner of the building. Two 30-in. butterfly valves are provided i n line 930 rather than one t o permit periodic testing for leak tightness of the valves. The space between the two valves may be pressurized w i t h air through valve 930-C. The shaft s e a l can also be pressurized t o t e s t for leaks. A 2-in. bypass,

line 955, i s provided around the two butterfly valves t o accommodate low flow rates. The space between the two valves i n t h i s l i n e may a l s o be pressurized w i t h air through valve 955-C t o check for leakage. The gas supply f o r the component cooling system blowers i s taken from line 930 j u s t upstream of the butterfly valves through the 10-in.diam line 522 (see Section 16). The =-in. pipe sham on the flowsheet as leaving line 930 upstream of the two butterfly valves leads t o the reactor cell vapor-condensing system. This arrangement f o r emergency condensing of water vapor t h a t might be generated i n the c e l l in a major failure of equipment i s described in Section 17. A 12-in. ventilation pipe, line 931, fromthe service tunnel area

joins the 30-in. pipe, line 930, j u s t downstream of the two butterfly valves. This pipe exhausts air from the western end of the tunnel t o

6. *

. 391

promote a positive flow of air toward that end.

A 6-in. continuation of

line 931, numbered 958, exhausts air from the special equipment room. Both of these lines contain manually operated dampers. The 30-in.-diam line 930 joins the main duct, line 927, above ground near the entrance t o the f i l t e r p i t . The f i l t e r p i t is arranged i n three sections, each section having

a p r e f i l t e r followed by an absolute filter.

The efficiency of the l a t t e r

i s 99.97s for particles greater than 3 p in size. Manually operated dampers are provided at the i n l e t and outlet of each section. Each of the six groups of filters i s provided w i t h differential pressure sensors t o indicate the condition of the f i l t e r s . Normally, a l l three sections are operated in parallel. The two stack fans are ducted in p a r a l l e l through lines 925 and 926, so that either may be used t o exhaust the containment enclosures. Stack fan No. 1w i l l operate continuously, w i t h the No. 2 fan in standby condition. Both manually operated dampers i n the fan suctions w i l l remain open. The air-operated damper in the No. 1 fan discharge, FCD-925, w i l l normally be open and that i n the No. 2 fan discharge, FCD-926, w i l l be closed. If the pressure increases upstream of the f i l t e r s , as indicated by PI-927, the No. 2 fan w i l l start, the No. 1 fan w i l l stop, and the air-operated damgers w i l l reverse position. This arrangement prevents backflow through the fan not i n use. The stack i s equippped w i t h a p i t o t tube, FI-S1, t o indicate the flow and t o transmit this information t o the data logger. A radiation monitor, RIA-S1, is installed in the stack. R a i n water accumulating i n the stack i s &rained t o the waste sump in the main building through a 2-in. stainless s t e e l pipe.

13.3 Description of Equipment

13.3.1 Inlet-Air F i l t e r House 13.3.1.1 House. The inlet- (or supply) air f i l t e r house serves as an enclosure for the dust f i l t e r s and tempering coils for the entering air. The structure i s 13 f t wide, 21 f t long, and 10 ft high; it has a concrete floor a t an elevation of about 840 ft and i s located 7

* . 1

392 outside the northwest corner of the main building.

The w a l l s and roof

are 14-gage corrugated s t e e l siding welded t o a channel and angle-iron supporting structure.

A portion of the i n t e r i o r w a l l s and roof i s in-

sulated with 1-1/2-in.

of "Fiberglas" (type m-617).

The insulated

section extends a distance of about 8 f t from the eastern end and surrounds the heating c o i l and the heated air plenum.

Two s t e e l doors are

provided for access (see ORNL drawing D-KK-D-41123). 13.3.1.2

Heating Coils.

The air heating c o i l s are of the one-row,

nonfreeze type, with welded steel headers and with copper tubes and aluminum fins.

Three units are used, each with a face area of about

12.7 ft2. S t e m i s supplied from the X-10 area a t 250 psig and reduced t o 60 psig a t a l-l/k-in. reducing valve located i n the supply-air f i l t e r house.

The combined capacity of the three units i s sufficient t o r a i s e

16,000 cfh of air from O°F t o 85OF.

The pressure drop across the c o i l

i s about 0.06 in. of SO. The c o i l s were tested with steam a t 100 psig and with air at 400 psig. The c o i l s were manufactured and tested i n accordance with American Standards Specification DS-1R-17-78 and OBNL Specification XS-192, p. 7-5.

13.3.1.3

Air-Supply F i l t e r s ,

The f i l t e r medium i s pleated 3/32-in.-

thick "Fiberglas" arranged in 24 x 28 x 8-3/4-in.-thick

units (American

Air F i l t e r type PL-24).

v e r t i c a l V's,

The units are placed i n three side-by-side, each leg of a V being two d i t s wide and three units high,

making a t o t a l of 36 units (see ORNI, Specification xs-192, p. 6-2).

13.3.1.4

buvers.

TWO

s t e e l louvers, each about 6 x 6 f t , with

bronze insect screen, admit air to the west end of the i n l e t - a i r house. A 30 x 48-in. louver i s located between the f i l t e r s and the heating coil,

as w i l l be discussed under Section 13.3.1.5,

13.3.1.5

Dampers and Ducts.

below.

A regulating damper i s mounted i n the

horizontal position j u s t above the intake-air house roof i n the 36 x 36-in. duct leading t o the high-bay area, l i n e 953. This steel, multi-blade damper i s manually adjustable and can be locked i n position (see ORNL drawing D-KK-A-41069) The damper i n the side of the i n l e t - a i r house between the f i l t e r s and the heating c o i l i s 29-5/8 x 47-5/8-in.,

i s mounted vertically, has 16-gage s t e e l blades, and has an adjustable counter-weight s e t t o open

u @

393

kd 8

the dampr at a negative air pressure of 0.35 in. of I$O,

A similar

damper, 29-5/8 x 47-5/8 in., horizontally mounted in the bypass duct,

line 954, at the roof of the intake air f i l t e r house i s weighted t o open a t a negative pressure of 0.45 in. of %O (see ORmL drawing D-KK-A-41069) The Buct leading t o the high-bay area i s constructed of 20-gage sheet m e t a l , insulated with 1-1/2 in. "Fiberglas" weatherproofed board. 13.3.2

Uquid-Waste Tank Blower

The blower used t o discharge gases f r o m the top of the liquidwaste tank i n t o the containment ventilation exhaust system i s located in the remote maintenance pump cell.

!&e blower i s an IIG type P volume blower, 6-in. line type, having a capacity of 180 cf'm.

13.3.3 Vent House A i r is drawn into the vent house through a 24 x 24-in. louvered

opening in the west w a l l .

The f i l t e r installed in this opening uses a

f i l t e r medium of "Fiberglas" and i s an American Air F i l t e r type PL-24, w i t h 3/32-in.-thick type G "Airmat." It has a IVBFU rating of C l a s s I and has a rated pressure drop at 1000 cfm of 0.028 in. of %O when clean, The actual f l o w i s estimated t o be a maximum of about 250 cfm.

13.3.4

Filter Pit

The filters i n the f i l t e r p i t are divided into three cells, o r sections, asd each section i s provided w i t h both roughing and absolute filters. 13.3.4.1 Roughing Filters. The roughing, o r pre-filters, are a modified American Air F i l t e r deep-bed, multiple-media, pocket type (see ORNL drawing D-IM-A-41075). The f i l t e r i n g media are a layer of spun glass 1/2 in. thick, made up of 3.25 micron fiber (No. 25 FG) and a 1/2-in.-thick layer of 1.25 micron fiber (No. 50 E). The units are 27 x 27 x 36 in. deep. The capacity i s not less than lo00 cf3n a t a velocity of 20 fpm and an i n i t i d resistance of 0.6 in. of Seven of the f i l t e r units are installed in a horizontal rack i n each of the three sections of the f i l t e r p i t (see O R m Specification XS-192, p. 6-3).

394

13.3.4.2

Absolute Filters. %e absolute filters, which are d m stream of the roughing filters in each of the three sections, are a "Fiberglas" fire-resistant high-efficiency type.153 The filter units are 24 x 24 x 11-1/2 in. deep, and are arranged vertically, two across 2 and three high, for a total of 24 ft of filter face area in each section. The minimum efficiency is 99.974 for particles greater than 3 microns in size (DOP test*) at the design flow rate of 1170 cf'm each.153 The initial static pressure loss is 1.05 in. of at a face velocity of 280 fpm. Operation is limited to 25OoF.

13.3.5 Stack Fans

Two centrifugal fans are installed outdoors at the base of the containment ventilation system stack. One of the fans serves as a spare. The fans are identical except for the direction of rotation, fan No. SF-1 being counterclockwise and No, SF-2 clockwise. Each is driven by a SO-hp, 440-v, 3-phase, 6O-cycle, continuous-duty motor, through an adjustable V-belt drive. The fan blades are the backward-curved, nonoverloading type. The capacity of fan SF-lwas measured as 19,750 cfm at 9.2 in. of 50 and 1473 rpm. Fan SF-2 delivered 20,500 scfm at 10.1 in. of %O and 1584 rpm. The minirmlm specified static efficiency is 835 under rated conditions of 21,500 scfm and 10 in. of 40 negative pressure. The maximum outlet velocity is 3800 fgm. The fan operating characteristics are shown in Fig. 13.2. The fans axe arranged for horizontal, bottom discharge, and the lowpoints of the scrolls axe provided with a 1-1/2-in0drain line. The fans and motors are weather-protected for outdoor installation (see ORIBL Specification XS-192, p. 6-4). The units were manufactured by the Fly Ash Arrestor Corporation and have the catalog designation 3938 51w.

13.3.6 Stack The stack is a free-standing type, 100 ft high, 3 ft ID at the top and 4 ft ID at the bottom, tapering to 3 ft ID about 25 ft above the concrete base (see Fig. 3.2 and OWL drawing D-KK-D-~UO). The carbon steel plate is ASm A 283 grade C, 1/2 in. thick in the bottom tapered section and 3/8 in. thick above.

Rectangular openings are provided for the two

*Dioctyl-phtholate aerosol test.

Unclassified ORNLDWG64-8842

Static

15 20 Flow Rate - 1,ooo cfbl

Figure 13.2.

Stack Fan Perfomance Curves

Pressure

396 discharge ducts from t h e stack fans.

E x t e r i o r ladder rungs a r e provided

L+ *

t o t h e top of t h e stack. Four equally spaced 1/2-in.

pipe couplings a r e i n s t a l l e d about

40 f t above t h e base f o r p i t o t tube flow measurements.

An opening i s

a l s o provided f o r i n s e r t i o n of a r a d i a t i o n monitor. The octagonal reinforced concrete base i s a t a grade elevation of 850 f t and i s 16 f t across t h e f l a t s and 7 f t thick.

The bottom of t h e

stack contains a 11-gage 304 stainless s t e e l d r a i n pan sloping toward a center d r a i n of 2-in.

sched-40 s t a i n l e s s s t e e l pipe.

This d r a i n l i n e

slopes t o a s o i l pipe which d r a i n s t o t h e building sump (see ORNL Drawing D-KK-A-41078).

13.4 Design C r i t e r i a Design of t h e containment v e n t i l a t i o n system was n e c e s s a r i l y based on c e r t a i n assumptions and broad estimates: 154

It was assumed t h a t during normal operation of t h e r e a c t o r t h e containment v e s s e l would be a t a negative pressure of 2.0 psig.

During main-

tenance operations t h e v e s s e l pressure would be about 0.3 in. of H20 below atmospheric.

The minimum downward v e l o c i t y through an opening i n t h e

c e l l roof would be 100 fpm.

(For an a i r discharge r a t e of 15,000 cfm t h e 2 maximum allowable opening would thus be about 150 f t .) The maximum leakage

* i n t h e c e l l system and exhaust duct was taken

t o be 1% of t h e c e l l volume i n each 24-hr period.

Leakage through t h e

two 30-in. b u t t e r f l y valves i n l i n e 930 w a s assumed t o be 1/14 of t h e

c e l l volume per 24 hr. The high-bay,

storage c e l l s , e t c . , were assumed t o be maintained at

0.1 in. of H 0 below atmospheric with a maximum negative pressure of 0.5 2 in. of H20. The maximum a i r leakage i n t o t h e containment v e n t i l a t i o n

system enclosures w a s taken t o be 6 x

cf’m p e r cubic f o o t of volume,

or about 900 cf’m, and t h e d e s i r a b l e a i r change rate not l e s s than about s i x per hour.

A l l occupied adjacent areas were required t o be a t a

p o s i t i v e pressure with respect t o t h e containment v e n t i l a t i o n system enclosures.

With t h e c e l l s a t 39 psig.

397

14. LIQUID WASTE SYSTEM The primary f’unction of t h e MSRE l i q u i d waste system i s t o c o l l e c t a l l waste water which is l i k e l y t o be contaminated, s t o r e and t r e a t it, when necessary, - _ and discharge it t o t h e Central Pumping Station of t h e Melton Valley Waste System. i55 The l i q u i d waste system a l s o includes a c e l l and tank f o r decontaminating t o o l s and reactor equipment.

Filter-

ing equipment i s provided t o c l a r i f y t h e water used f o r shielding i n t h i s c e l l t o obtain b e t t e r v i s i b i l i t y of work being done underwater. A

sump, which normally handles non-contaminated general building drainage, i s a l s o associated w i t h t h e l i q u i d waste system.

14.1 Layout and Gemral Description The l i q u i d waste system equipment i s i n t h e l i q u i d waste c e l l , t h e decontamination c e l l , t h e remote maintenance p r a c t i c e c e l l , and t h e sump room.

The t h r e e c e l l s a r e beneath t h e operating floor level, as shown

i n Figs. 4.3 and 4.5.

The sump room i s beneath t h e s p e c i a l equipment

room, and w i t h a sump elevation of -812 f t , i s t h e point of lowest elevation i n Bldg. 7503.

14.1.1 Liquid Waste Cell The l i q u i d waste c e l l i s 14 x 21 ft and 24 ft deep, with a floor elevation of 828 ft (See Table 4.3).

This a u x i l i a r y c e l l i s located

between north-south columns 2 and 3, and east-west columns A and B, i n Fig. 4.4.

The c e l l contains a 11,000-gal storage tank for waste water,

t h e waste f i l t e r , and associated piping and remotely operated valves. Concrete s h i e l d blocks form t h e roof of t h e c e l l but t h e r e i s no membrane t o make t h e enclosure pressure t i g h t .

The containment v e n t i l a t i o n system

exhausts a i r from t h e c e l l t o provide a down-dra3’t through t h e small openings between t h e roof plugs t o contain airborne contaminants Section 13)

(See

14.1.2 Decontamination Cell The decontamination c e l l i s located j u s t south o f , and adjacent t o , t h e l i q u i d waste c e l l .

The c e l l i s 14 x 15 ft, about 20 f t deep, and

398 has a f l o o r elevation of 832 f t - 6 i n .

The c e l l can be f i l l e d with water

f o r shielding l a r g e r radioactive items of equipment which require main-

tenancetor.decontamination. The only equipment i n t h e c e l l i s t h e decontamination tank and simple piping and valves.

The c e l l can be covered

with concrete roof plugs and v e n t i l a t e d i n t h e same manner as t h e l i q u i d waste c e l l , but it may remain open most of t h e time.

14.1.3 Remote Maintenance Practice C e l l This c e l l i s e a s t of, and adjacent t o , t h e l i q u i d waste c e l l , see Fig. 4.4. ft.

It i s 13 x 21 ft and 24 ft deep with a f l o o r elevation of 828

The c e l l i s used t o p r a c t i c e maintenance procedures before they a r e

c a r r i e d out i n t h e r e a c t o r c e l l .

The c e l l i s a l s o used t o house t h e waste

pump and associated valves which t r a n s f e r l i q u i d *om tank.

t h e l i q u i d waste

The small18o-cf'm blower which removes gases from t h e top of t h e

l i q u i d waste tank i s a l s o located i n the c e l l (See Section 13.3.2).

14.1.4 Sump Room The sump room i s an 8 x 16-f't x 7-ft-high space with a f l o o r elevation of 820 f't.

In t h e f l o o r of t h e room i s a 3 x 3 x 8-ft-deep sump, which i s

t h e lowest point o f elevation i n t h e main building.

The room i s located

p a r t i a l l y beneath t h e s p e c i a l equipment room between columns 8 and 9, and C and B, i n Fig.

4.4.

Access t o t h e sump room i s by a 3 O - r t v e r t i c a l ladder

through an opening i n t h e floor o f t h e southern end of t h e high-bay a r e a . P o s i t i v e v e n t i l a t i o n of t h e sump room i s achieved by a blower i n t h e room which discharges up a small duct i n t o t h e high-bay a r e a .

The sump room

contains a 55-gal s t a i n l e s s s t e e l drum f o r c o l l e c t i n g water which could possibly be contaminated, and a c e n t r i f u g a l pump f o r t r a n s f e r r i n g i t s contents.

The room i s also provided with two pumps mounted i n t h e sump

f o r pumping out uncontaminated water. 14.2

Flowsheet

The flowsheet f o r t h e l i q u i d waste system i s shown i n Fig. 14.1 I

(ORNL Dwg ~-AA-A-40888). Eleven l i n e s empty i n t o t h e top o f t h e 11,000-gal waste tank, as follows :

L, B

399

DECONTAMINATION CELL

DECONTAMINATION TANK

'-40-SS

RoloIL YIlWTENAMCE PRACTICE CELL

-I

mo cry-

TO OFF GAS FLrERS

+ ACCESS

DOOR

e--

4-x

1 1I

t-40-ssJ

LlPUlD WASTE STORAGE TANK (WT)

NO TRANSMITTER ROC M

AS BUILT

(WFI

CHANGES 2- 40-SS

LIQUID WASTE CELL

! u 1.

I .

6. P

t: l y w ~

. .

__-

LIQUID WASTE SYSTEM PROCESS FLOW SHEET 4n-m

I M. S. R. E.

400

Steam-actuated ejectors i n thevsumps of t h e l i q u i d waste c e l l , the equipment storage c e l l , t h e f u e l processing c e l l , and t h e spare c e l l , discharge i n t o the l i q u i d waste tank through l i n e s 316, 318, 320 and 322, respectively.

These a r e a l l 3/4-in. sched 40 s t a i n l e s s s t e e l pipes.

The steam ejectors a r e supplied with 60-psig saturated steam through l i n e s

315, 317, 321 and 319, respectively.

Each of t h e steam supply l i n e s con-

t a i n s a check valve t o serve as a vacuum breaker. The steam ejector which empties the caustic scrubber tank i n t h e fuel processing c e l l , i s supplied with 60-psig steam through l i n e 312. j e t discharges through a 3/4-in.

The

sched 40 monel pipe, l i n e 314, t o t h e top

of t h e waste storage tank. The swrrps i n t h e reactor and drain tank c e l l s a r e equipped with l i q u i d l e v e l indication through use of bubbler l i n e s 965 and 966, respectively. These 1/2-in. sched 40 s t a i n l e s s s t e e l l i n e s are supplied w i t h nitrogen f o r purging oxygen from t h e c e l l s and contain rotameters of up t o 0.31 l/min capacity.

The bubbler l e v e l indication i s i n addition t o t h e l e v e l alarm

switches which are provided on a l l sumps. The above-mentioned suxps i n t h e reactor and drain tank c e l l a r e emptied by ejectors ac$uated by service a i r .

The 100-psig supply air i s

passed through a pressure regulator, PCV-332, and d i s t r i b u t e d t o t h e drain tank c e l l through l i n e 342 and t o the reactor c e l l through l i n e 332. of these l i n e s are 3/4-in,

Both

sched 40 s t a i n l e s s s t e e l and have hand-operated

valves and check valves t o prevent back flow from t h e c e l l s .

The reactor

c e l l j e t discharges into l i n e 333 and t h e drain tank c e l l j e t into l i n e

343, both of which a r e 3/4-in. sched 40 stainless s t e e l pipe leading t o t h e liquid waste storage tank.

Before entering t h e storage tank, each l i n e i s

provided with two flow-control valves i n series, FCV-333-A, FCV-333-B and

FCV-343-A, FCV-343-B.

These normally-closed, air-operated valves a r e i n t e r -

locked t o close on a sudden r i s e i n reactor c e l l pressure.

Lines 334 and

344 permit t h e application of a test pressure between t h e two flow-control valves t o check f o r leak tightness.

The reactor and drain tank c e l l s can

be depressurized f o r leak t e s t i n g through t h e j e t discharge l i n e s .

A sink i n t h e change room, located east of t h e high bay, and p a r t o f the controlled ventilation area, has a drain, l i n e 340, leading t o t h e waste storage tank.

A f'unnel i s provided i n t h e high-bay area for t h e

401 addition of c a u s t i c t o t h e l i q u i d waste tank, through l i n e 339.

(The l i q u i d waste i s made a basic solution before t r a n s f e r t o t h e Melton Valley

waste disposal system. ) The discharge of t h e waste pump, located i n t h e remote maintenance p r a c t i c e c e l l , may be d i r e c t e d i n t o t h e waste storage tank through t h e 2-in. sched 40 s t a i n l e s s s t e e l l i n e 301.

The waste pump discharge may

a l s o be diverted t o t h e waste f i l t e r located i n t h e l i q u i d waste c e l l through t h e 2-in. pipe, l i n e 302.

The discharge of t h e waste f i l t e r i s

through l i n e 306 t o be returned e i t h e r t o t h e decontamination c e l l o r decontamination tank.

Line 307, connecting t h e waste pump discharge t o l i n e

306, permits r e c i r c u l a t i o n of water i n t h e decontamination tank, o r p a r t i a l *

by-passing of t h e f i l t e r when r e c i r c u l a t i n g t h e water; it a l s o allows process water t o be added t o t h e waste storage tank v i a l i n e s 819, 306, 307 and 301. The sump pump drawing l i q u i d from t h e 55-gal contaminated storage drum, r e f e r r e d t o as t h e " p i t pump" t o d i s t i n g u i s h it from t h e sump pumps a l s o located i n t h e sump room, can discharge i n t o t h e l i q u i d waste tank through

a 2-in. pipe, l i n e 326.

The pressure r e l i e f valves i n t h e t r e a t e d water

system serving t h e r e a c t o r and d r a i n tank c e l l s discharge i n t o t h e 1-1/4i n . l i n e 335, which joins t h e afore-mentioned l i n e 326 f o r r e l e a s e i n t o t h e waste storage tank (See Section 15.10). The waste tank i s vented through t h e 6-in. sched 10 s t a i n l e s s s t e e l pipe, l i n e 948, which leads t o t h e remote maintenance p r a c t i c e c e l l , where €

a small i n - l i n e blower of 180 cf'm capacity i s i n s t a l l e d i n t h e pipe t o provide a p o s i t i v e movement of t h e gases i n t o t h e containment v e n t i l a t i o n exhaust system (See Section 13.3.2).

The only bottom connection on t h e waste storage tank is l i n e 300, a 2-1/2-in.

sched 40 s t a i n l e s s s t e e l pipe leading t o t h e suction of t h e waste

pump i n t h e adjoining c e l l .

The bottom of t h e decontamination tank i n t h e

decontamination c e l l a l s o drains i n t o l i n e 300, and t h e pump suction, through a 2-1/2-in.

pipe, l i n e 304.

The sump i n t h e floor of t h e decon-

tamination c e l l c m be pumped out by t h e waste pump through l i n e 303, which j o i n s t h e afore-mentioned l i n e 304 inside t h e decontamination c e l l . t

u 4

The waste pwrp discharges through l i n e 305, a 2 - i n . sched 40 s t a i n -

l e s s s t e e l pipe containing a pressure-measuring t a p and sample p o i n t .

402

Downstream of valve 3O>-A, t h e pump discharge l i n e continues as a 3-in.

c a s t i r o n pipe t o t h e c e n t r a l pump s t a t i o n of t h e Melton Valley waste system, which i s located j u s t w e s t of t h e Bldg 7503 a r e a . The sump i n t h e sump room receives general building drainage, as l i s t e d i n Table 14.1.

This water w i l l not normally be contaminated.

Two 1.5-hp 75-gpm f l o a t - c o n t r o l l e d sump pumps remove t h e w a t e r and d i s charge it through a 3-in. pipe, l i n e 327, t o a concrete catch basin.

This

basin, about 2 x 3 f't and 6 f't deep, i s located just w e s t o f t h e charcoal bed and has a bottom elevation of 846 ft. It d r a i n s through a 150-f't-long 12-in. reinforced concrete pipe away from t h e s i t e toward t h e n a t u r a l drainage leading t o Melton Branch. The overflow l i n e from t h e charcoal bed c e l l empties i n t o t h e abovementioned sump p

q discharge, l i n e 327 and thence t o t h e catch b a s i n .

Line 327 i s provided with a check valve upstream of t h i s connection t o prevent t h e overflow from moving backwards down t h e l i n e i n t o t h e sump.

It i s p o s s i b l e for contamination t o be present i n t h e drainage f r o m t h e bottom of t h e f i l t e r p i t and from t h e bottom o f t h e containment v e n t i l a t i o n system exhaust s t a c k .

Each of t h e two 2-in. s t a i n l e s s s t e e l

d r a i n pipes from t h e f i l t e r p i t has a s i g h t i n d i c a t o r and a hand valve i n t h e concrete f i l t e r p i t valve box located j u s t east o f t h e f i l t e r p i t .

The

two l i n e s combine, as l i n e 351, and j o i n t h e 3-in. c a s t i r o n d r a i n l i n e from t h e bottom o f t h e stack, l i n e 350, which i n t u r n empties i n t o t h e 55-gal s t a i n l e s s s t e e l drum i n t h e sump room. The 3-hp p i t pump can remove water from t h e drum through t h e 3-in.

suction, Line 325, and discharge it v i a l i n e 326 t o t h e l i q u i d waste storage tank.

If t h e r e i s no objectionable contamination, t h e drainage

water can be pumped through l i n e 330 and 3 3 1 t o t h e above-mentioned catch basin for r e l e a s e t o t h e n a t u r a l drainage from t h e s i t e .

Check valves i n

both l i n e s 326 and 330 prevent backflow i n t o t h e sump from t h e p

q dis-

charge l i n e s . Line 328 i s a 3-in. c a s t i r o n pipe i n s t a l l e d t o d r a i n water from t h e charcoal bed c e l l .

A s i m i l a r arrangement i s provided i n l i n e 329 t o d r a i n

water from t h e r e a c t o r containment v e s s e l c e l l annulus.

It i s u n l i k e l y

that e i t h e r of t h e s e spaces w i l l be drained frequently.

The two d r a i n

l i n e s combine i n t h e sump room t o j o i n l i n e 325 a t t h e p i t pump suction.

b ;

403

Table 14.1 Lines Emptying i n t o Sump i n Sump Room Line Number

Size

m e

From

352

3 in.

Bottom of radiator a i r duct

3 53

3 in.

Bottom o f radiator cooling a i r stack

354

3 in.

Steel

355

3 in.

Blower house

356

3 in.

Blower house ramp

3 57

3 in.

West tunnel

358

4 in.

Service room

359

.3 i n

Steel

Service tunnel

360

4 in.

Service tunnel French drain

361

4 in.

Reactor c e l l French drain

362

4 in.

Charcoal bed c e l l French drain

363

4 in.

French drain for SE area o f bldg.

364

3 in.

Coolant drain c e l l

365

2 in.

Vent house valve p i t

Bottom of coolant drain c e l l

404 The water can thus be pumped out of t h e sump room by t h e p i t pump t o t h e waste storage tank o r t o t h e natural drainage from t h e s i t e .

6' e

If necessary,

it could a l s o be dumped i n t o t h e sump room sump f o r removal by t h e sump pumps. Check valves i n both l i n e s 328 and 329 prevent backing up i n these l i n e s due t o t h e difference i n elevation. The r e a c t o r c e l l annulus i s a l s o provided with an overflow pipe, l i n e 331, which drains t o t h e catch basin outside.

A check valve i n l i n e 330, from t h e p i t pump discharge, which

j o i n s l i n e 331, prevents t h e overflow water from moving backward through t h e pump i n t o t h e sump.

14.3 Description of Equipment

14.3.1 Liquid Waste Storage Tank The waste storage tank is 11 ft d i a m and 16 ft high, giving a storage capacity of about 11,000 gal.

The tank i s always vented t o operate a t es-

s e n t i a l l y atmospheric pressure.

The tank has a f l a t bottom r e s t i n g on t h e

concrete f l o o r o f t h e waste tank c e l l .

The t o p i s a dished head contain-

ing a 12 x 16-in. manhole, eleven flanged nozzles f o r i n l e t l i n e s , and a 6-in. nozzle f o r t h e vent l i n e .

The discharge i s a 2-1/2-in.

dip pipe t o

t h e bottom which penetrates t h e tank wall about 18 i n . above t h e lower circumferential weld.

The tank i s made of 1/4-in. 304 s t a i n l e s s s t e e l

(See ORNL Dwg D-KK-B-41283). 14.3.2

Waste F i l t e r

The waste f i l t e r i s a Cochrane, Type A, vertica1,pressure f i l t e r . tank i s 3 f't

The

6 i n . i n diam and 48 i n . high between t h e head welds, and has

dished top and bottom heads.

The tank i s r a t e d a t 100 psig, but i s not a

The f i l t e r bed c o n s i s t s of a 34-in. depth of graded sand and 2 gravel having a cross s e c t i o n a l a r e a of about 9.6 f t Water e n t e r s through Code v e s s e l .

a 2-in. pipe i n t h e top head and i s d i s t r i b u t e d uniformly by a concave The underdrain i s through a convex, s l o t t e d d i f f u s e r p l a t e welded 2 o r a t o t a l of 38 gpm, with t o t h e bottom head. The capacity i s 4 gpm/ft

baffle.

a maximum pressure drop due t o flow through it of 5 t o 10 p s i .

The f i l t e r

can be cleaned by back washing with process water, t h e normal back wash

405 requiring 5 t o 15 min a t a flow r a t e o f 10 t o 13 &pm/ft

, o r a t o t a l of

96 t o 144 a m , at pressures of 20 t o 25 psig.

14.3.3 Waste Pump The waste pump i s located i n t h e remote maintenance practice c e l l .

It is a canned-motor unit, Chempmp Tyye CH-5, and has a 2-in. suction, a 1-1/2-in.

discharge, and a 6-1/2-in.

impeller.

It i s rated a t 1% p s i g

and w i l l deliver 140 gpm against a head of 80 ft. The motor i s rated a t 10 hp, and it i s supplied with 3-phase, &-cycle power from t h e %-amp

c i r c u i t breaker No. 23 on t h e G-4 motor control center.

14.3.4

Sump Pumps

The two surnp pumps i n t h e sump room a r e rated a t 75 a m , with a d i s charge head of 40 I% The, motors a r e rated a t 1.5 hp

. The power supply

is through motcr control center G-3-3 and a 30-amp c i r c u i t breaker.

The

pumps a r e controlled by float-operated switches.

14.3.5 P i t Pump The p i t pump i n t h e sump room i s a Peerless u n i t rated a t 200 gpm a t a discharge head of 70 f’t. It has a 3-in. suction and a 2-in. discharge. The motor i s rated a t 5 hp.

The e l e c t r i c a l supply i s through t h e motor

control center G-3-3 and t h e same 30-amp c i r c u i t breaker used f o r t h e sump

pump, described above.

14.3.6 Jet Pumps

The j e t s used t o evacuate t h e sumps i n t h e various c e l l s are Penberthy e j e c t o r s , Model ~ ~ 9 Series 6 , 2 A (Penberthy Manufacturing Company), having

capacities a t various conditions as l i s t e d i n Table 14.2.

The sump j e t s

normally operate with a suction head of about 2 f’t. and t h e caustic scrubber j e t has a suction head of about 12 ft. The j e t s i n t h e reactor and drain tank c e l l s a r e a i r operated and those i n t h e a u x i l i a r y c e l l s are actuated

by steam.

14.4 Design C r i t e r i a #

The primary requirement of t h e l i q u i d waste system i s t h a t a l l

406

Table 14.2

Sump Ejector Characteristics* Pwnping Water Steam o r A i r Supply Pressure 60 Psig 90 p s i g

Suction Head ft H20

30 p s i g

Water delivery (130°F )

8.5 &Dm

8.1 @;pm

7 -25 gpm

Water delivery (13OOF)

4.6 gpm

6.6 gem

5.75

Steam consumption

1.3 lbs/min

1.9 lbs/min

2.6 lbs/min

A i r consumption

26 scfm

38 scfm

52 scfm

Pumping A i r

5 A i r capacity a t suction (at 40 p s i g supply pressure)

50 scfm

Vacuum, in. Hg 10 15

17 scfm

*Penberthy Mfg. Co. Ejector Type x ~ g 6Series 2 A .

7 scfm

4 scfln

" 5

407 agueous effluent from t h e MSRE which might be contaminated be collected and stored, t r e a t e d w i t h caustic when necessary, and discharged t o t h e c e n t r a l purqp s t a t i o n of t h e Melton Valley waste system, located j u s t west of t h e Bldg 7503 a r e a . Although not a d i r e c t p a r t of t h e system, t h e l i q u i d waste arrangement a l s o includes provisions f o r collection o f c e r t a i n non-radioactive general building drainage and disposing it t o t h e natural drainage from the s i t e .

This general building drainage does not include storm water

o r t h a t from t h e sanitary system. A requirement f o r operation of t h e decontamination c e l l i s t h a t the shielding water be circulated through a f i l t e r t o permit b e t t e r v i s i b i l i t y f o r underwater operations.

The j e t e j e c t o r s used t o remove water from the sumps i n t h e reactor and drain tank c e l l s a r e operated by dry a i r r a t h e r than by steam t o avoid t h e introduction of moisture i n t o t h e c e l l . The j e t s removing water from t h e sumps i n t h e a u x i l i a r y c e l l s a r e steam-actuated. densed and e a s i l y retained.

"he steam i s con-

408

15.

COOLING WATER SYSTESI

15.1 Layout and General Description

The MSRE cooling water f a c i l i t i e s include the potable water, process water, cooling tower, treated water and condensate systems. The potable water system d i s t r i b u t e s water supplied from the X-10 area of O m , as described i n Section 3.

T h i s system provides

f o r f i r e protection, s a n i t a r y uses and drinking water.

A portion of

this potable water, after passing through a back-flow preventer,

supplies the process water for cooling tower make-up, e t c .

The

potable w a t e r supply l i n e is a t the north end of Bldg. 7503 and e n t e r s the building a t t h e northeast corner. The cooling tower water s y s t e m i s a c i r c u l a t i n g system i n w h i c h the water is cooled by a 2.75 x lo6 Btu/hr forced-draft cooling tower

located southwest of the building, see p l o t plan, Figure 3.2.

Either

of two outdoor 20-hr, 8 0 - f t head, c e n t r i f u g a l pumps of 547 gpm capa-

c i t y , c i r c u l a t e s water from the tower basin t o t h e treated water cooler and other equipment l i s t e d i n Table 15.1. Water from the cooling tower is a l s o used t o cool t h e charcoal beds but t h i s water is discharged t o d r a i n and is not c i r c u l a t e d . The treated water system is a closed c i r c u l a t i n g system contain-

ing condensate w i t h an added chemical i n h i b i t o r t o minimize corrosion.

Water from this system is used f o r cooling equipment i n which t h e r e is a p o s s i b i l i t y of the water becoming contaminated. The equipment cooled is l i s t e d i n Table 15.2. The water i s c i r c u l a t e d by either of two 20-hp, l36-ft-head, 320-gpm c e n t r i f u g a l pumps located i n the

water room i n the blower house a t the southwest corner of Bldg. 7503. The treated water passes through a shell-and-tube type heat exchanger i n the Diesel house t o be cooled by t h e cooling tower water system. The water is d i s t r i b u t e d by a header i n the water room and metered t o the various items of equipment.

The r e t u r n l i n e s discharge i n t o a

common header leading t o the pump suction.

A surge tank i s provided

for the expansion of t h e water i n t h e closed system.

T h i s vented

409

w Table 15.1 Equipment Cooled By Cooling Tower Water Flow, gpm Treated water cooler

260

1.53 x lo6

A i r compressors ( t o t a l for 3)

0.36 x lo6**

Fuel pump lube o i l system

7.5

0.035 x lo6

Coolant pump lube o i l system

7.5

0.035 x lo6

Drain tank condensers (each of 2)

Caustic scrubber and HF t r a p

0.336 x lo6

Steam condenser

0.5

Charcoal beds

Table 15.2

Flow, gpm 100

3.94

x lo6

Heat Removed, Btu 0.41 x lo6

Fuel pump motor

0.005 x lo6

Coolant pump motor

0.010 x 106

Reactor c e l l a i r coolers ( t o t a l f o r 2) Drain tank c e l l air cooler

120 60

0.512 x lo6 0.256 x lo6

Nuclear instrument penetration

Gas coolant pump lube o i l system Gas cooler

f = Intermittent operation

** = Maximum values

Equipment Cooled by Treated Water

Reactor thermal shield

x lo6

0.168 x lo6 TOTAL

.y,

Reactor c e l l annulus makeup

..-

x 106**

Reactor c e l l annulus A i r conditioners ( t o t a l for 3)

Coolant c e l l coolers (each of 2)

Heat Removed, Btu

0.237 x lo6 20

410

tankhas a float-operated valve f o r makeup from t h e condensate system

and has provisions f o r a d d i t i o n of corrosion i n h i b i t o r s amounting t o 2,000 ppm of potassium oitrate (75s) and potassium borate (25%). Condensate is used f o r makeup i n t h e treated water system and for makeup t o the b o i l i n g water decay heat removal system i n the f u e l

d r a i n tanks.

The condensate is provided by condensing steam supplied

from the X-10 area of QRNL.

The shell-and-tube type condenser is

located i n the water room and is s t o r e d i n two nearby 500-gal tanks. 15.2

Flowshee t

The cooling water system flowsheet i s shown i n Figure 15.1

(ORNL-DWG-D-AA-A-40889) and includes t h e cooling tower, treated water and condensate systems.

The potable w a t e r supply i s a l s o shown in-

s o f a r as it is connected t o the r e a c t o r processes, but does not include building s e r v i c e s . Appropriate flowmeters and indicators are provided a t a l l points i n the system w h e r e water flow rates are needed f o r heat balance c a l culations.

In general, these are not mentioned i n the following

discussion, as they are covered i n d e t a i l i n Part 11. 15.2.1

Potable and Process Water

Two 6-in. carbon s t e e l pipes supply Bldg. 7503 from the water

One is a potable supply f o r general building use.

main a t the road.

The other, l i n e 894, supplies the r e a c t o r processes through a 4-in.

backflow preventer.

'The backflow preventer, BFP-890-1, has a relief

l i n e discharging t o a floor d r a i n i n t h e n o r t h end of t h e main building, and i s o l a t i o n valves V-894-Bl and V-890-A1, which can be closed f o r maintenance.

Additional valves, V-894-B2 and V-89042, are pro-

vided i n event it is necessary t o i n s t a l l an a d d i t i o n a l backflow

preventer f o r temporary use.

Water from t h e backflow preventer is d i s t r i b u t e d through 890, a 6-in. header.*

A branch from the header, l i n e 896, supplies process

water f o r general process use i n t h e high bay area.

Line 892 is a

Water taken from this potable water header i s sometimes referred t o i n this r e p o r t and i n t h e E R E literature as process water.

SHIELD

W Y P MOT0

+'a

FRCU REACTOR CELL ANNULUS

TO REACTOR CELL ANNULUS

FROM REACTOR THERMAL SHIELD

FROM FUEL PUMP MOTOR

TO VAP'R COMENSNG S K T E M

FROM REACTOR AIR COOLER NO

FROM REACTOR C AIR COOLER NO1

FROM DRAIN TANK

TO WASTE TANK

TO EIUCLEAR INSTRUMENT PENETRATION

TO DRAIN TANK C E L L AIR CDOL

F R W C ' W L A N T PUMP MQT

T 3 COOLANT

TO REACTOR C E L L AIR COO

TO REACTOR C E t L Pr(FreW:€R

TO F U E L PUMP MOTOR

TO REACT3R THERMAL

DRAIN TAYK CONDENSER NO. 2

L-

4Q GPY'

I 'I I

I I I

I I I I

.. . . ,..

.."I.

412

1-1/2-in. pipe f o r supplying water t o the vapor condensing tank used i n the vapor condensing system f o r the reactor containment c e l l .

The

l i q u i d waste c e l l is supplied w i t h potable water through the 2-in. l i n e 819.

A backflow preventer i n this line, BFP-819, is located i n

t h e w e s t side of the l i q u i d waste c e l l , and prevents contamination of

the cooling tower water system by reverse flow.

Ehergency cooling water is supplied t o the two instrument a i r compressors and the service a i r compressor located i n the Diesel house, through 2-in. l i n e 872.

These u n i t s are normally cooled by

the cooling-tower water system.

The condensers i n the f u e l drain

tank decay-hest removal system a l s o have an emergency water supply

from the process water system through the 2-in. l i n e 882, and threeThe normal coolant f o r the condensers i n the

way valve Iozv-882.

d r a i n tank system is cooling tower water. 1-1/2-in.

Line 890 continues as a

schd 40 pipe t o provide makeup f o r the cooling tower basin

through the float-operated valve, LCV-890. 15.2.2

Cooling Tower Water System

Water from the cooling tower basin is supplied through a 6-in. pipe, l i n e 850 and 852, t o the suction of the cooling tower water c i r c u l a t i n g pumps. Pump No. 1 discharges through a check valve i n t o l i n e 851 and Pump No. 2 i n t o l i n e 853. and a maximum temperature of 85'F, header, l i n e 851.

T h i s water, a t about 35 psig,

is d i s t r i b u t e d through the 6-in.

A major take-off, a l s o numbered 851, i s a 6-in.

pipe supplying about 260 gpm of cooling water t o the shell-and-tube cooler i n the treated water system.

This water c i r c u l a t e s back t o

the cooling tower through l i n e s 854 and 856.

A 1-1/4-in.

pipe, l i n e

880, is connected t o l i n e 851 f o r the 36-gpm cooling water supply t o the instrument a i r and service a i r compressors, and associated a f t e r coolers, a l l located i n the diesel house. The water is returned through lines 881, 854 and 856. The other major branch of l i n e 851 is the 3-in. take-off, l i n e

860, supplying a subheader, l i n e 816. Lines 821 and 823, each 1-1/4 in. supply about 7.5 gpm from this header t o the f u e l and coolant

salt circulating pump lubricating o i l system coolers located i n the

...

.. . .

" ., ,

.~I

413

service tunnel.

This water r e t u r n s t o t h e cooling tower through l i n e s

820 and 822 v i a l i n e s 817 and 856.

A 1-1/2-in. pipe, l i n e 891, from

l i n e 816 is used t o f i l l the annulus around the reactor c e l l containment vessel. The c a u s t i c scrubber cooling jacket i n t h e f u e l processing c e l l is supplied through l i n e 842 and returned through l i n e 843. off from the 3/4-in.

A take-

l i n e 842, the 1/2-in. l i n e 839, supplies water

t o t h e cooling jacket on the HF t r a p and HJ? cylinder i n the a r e a outside of Bldg 7503, j u s t w e s t of t h e d r a i n tank c e l l .

The cooling

water is returned t&hroughl i n e s 843 and 849, v i a l i n e s 817 and 856. Line 816 a l s o supplies water t o the steam condenser i n the water room, previously mentioned as the source of water f o r the condensate system t o be described subsequently, throtlgh the 1-1/4-in. water is returned through l i n e 815.

l i n e 814.

This

Also as previously mentioned,

the d r a i n tank heat removal system condensers are supplied with about 40 gpm each of cooling water through the 2-in. pipes 810 and 812, through a three-way valve HCV-882.

The r e t u r n water l i n e s from the condensers

are numbered 811 and 813. The main cooling tower water r e t u r n header, l i n e 856, i s a 6-in.

pipe leading t o t h e t o p of the tower. A 3-in. subheader, l i n e 817, c o l l e c t s much of t h e water flowing i n t o this main header. Line 856

divides t o supply both sections of the cooling t o w e r .

The water is

normally returned a t a temperature no h o t t e r than 95"F, and under

maximum ambient w e t bulb temperature conditions of 79°F could be cooled t o 85°F (7°F approach).

Since t h e commonly-used design w e t

bulb temperature i n the Oak Ridge area i s 75'F,

cooler water tempera-

tures can be attained, p a r t i c u l a r l y during the winter months.

A 4-in.

by-pass, l i n e 858, leads through t h e c o n t r o l valve, TCV-858, t o the tower circulating-pump suction t o r e g u l a t e t h e pump discharge

temperature. 15.2.3

Treated Water System

Condensate from the storage tank i n the water room is added t o the treated water system surge tank, located d i r e c t l y beneath it,

414 through l i n e 825. T h i s 1-in. pipe contains a float-operated c o n t r o l valve, Lcv-825, t o maintain ao operating l e v e l i n the tank. The surge tank is vented t o atmosphere a t a l l t i m e s .

Potassium n i t r i t e (75$),

and potassium borate (25%) are added through a funnel t o inhibit corrosion i n the treated water system.

The surge tank i s connected t o

l i n e 827 by two pipes, one on each side of valve V-827-C. The down-

stream l i n e i s a d i r e c t connection t o l i n e 827 and t h e upstream one contains a valve, V-827-D. This arrangement allows some of the flow i n l i n e 827 t o be diverted t o flow through the surge tank f o r mixing purposes and also assures that t h e surge tank i s always connected t o the system. c

The above-mentioned l i n e 827 is a 4-in. header leading t o the

suctions of t h e treated water c i r c u l a t i n g pumps.

A duplex s t r a i n e r

is included i n the l i n e upstream of the surge tank connections.

The

pump discharge l i n e s , 829 and 835, combine t o form l i n e 829. This 4i n . pipe d e l i v e r s the water a t 100°F and 58 psig, and a t a flow rate of about 300 gpm, t o t h e treated w a t e r f i l t e r located i n the Diesel house.

The f i l t e r when clean has a pressure drop of less than 1 p s i

and a maximum pressure drop of 5 p s i , and removes e s s e n t i a l l y a l l p a r t i c l e s greater than 30 microns i n diameter.

After leaving t h e

f i l t e r t h e water e n t e r s t h e treated water cooler, where it is cooled

t o about 90°F. It leaves the heat exchanger a t about 43 p s i g through the 4-in. sched 40 d i s t r i b u t i o n header, l i n e 826. The following

equipment is supplied from t h i s header i n t h e water room, each connection being provided with a hand-operated regulating valve, a flow indicator, s t o p valve, check valve, and a sampling valve arrangement t o t e s t t h e leak t i g h t n e s s of the check valve:

(a). The thermal s h i e l d f o r t h e r e a c t o r is cooled by 60 gpm of t r e a t e d water supplied through a 2-1/2-in. pipe, l i n e 844, and rec i r c u l a t e d t o t h e system through l i n e 845. A normally-open block valve on t h e supply, FSV-844, is controlled by a pressure switch,

PSS-844B, on l i n e 844 t o l i m i t t h e water supply pressure t o about 16 A flow-limiting o r i f i c e i n l i n e 844 a l s o prevents overpressuring t h e thermal s h i e l d if the manual flow a d j u s t i n g valve, V-844A, is opened too w i d e . Line 844 contains a check valve upstream psig.

415 of t h e o r i f i c e t o prevent back flow.

Rupture discs, rated a t 18 psig,

i n l i n e s 844 and 845 discharge t o l i n e 855 leading t o the vapor condensing system. (b) The f u e l pump motor cooling water is taken from l i n e 844,

described i n (a) above, downstream of the block valve FSV-844.

This

1-in. pipe, l i n e 830, i s provided with a check valve, located i n the blower house.

The required flow r a t e i s about 5 gpm and the water is

returned througb l i n e 831. l

This l i n e , and the r e t u r n water l i n e from

the thermal shield, l i n e 845, combine i o the blower house t o form l i n e 847.

This l i n e contains a block valve, FSV-847, which is a l s o

controlled by a radiation monitor, RE-827. (c) The reactor c e l l air cooler (No. 1) i s supplied with 60 gpm of treated water through the 2-in. l i n e 840. check valve located i n the blower house.

This l i n e includes a

Water is returned from the

a i r cooler through l i n e 846, through a block valve, FSV-846.

A relief

valve set a t 100 psig is included i n the r e t u r n l i n e upstream of the block valve t o vent excessive pressure through the 1-1/4-in.

l i n e 335

t o the waste tank. (d) The other reactor c e l l a i r cooler (No. 2) is supplied with

60 gpm of treated water through l i n e 838 i n the same manner as the cooler connections described i n (c), above.

The r e t u r n water is

through l i n e 841. (e) The coolant s a l t pump drive motor requires about 5 gpm of c

cooling water, supplied through 1-in. line 832, and a check valve, C'V-832.

The r e t u r n water is through l i n e 833 d i r e c t l y t o l i n e 827.

( f ) The 60-gpm treated water supply t o the d r a i n tank c e l l a i r cooler is through l i n e 386, a 2-in. sched. 40 pipe with a check valve located i n the blower house.

The r e t u r n water pipe, l i n e 837, is

equipped with a block valve, FSV-837, and a relief valve venting t o l i n e 335, i n a similar arrangement to the reactor c e l l a i r coolers. ( g ) The nuclear instrument tube penetration is f i l l e d with

water from t h e treated water system.

the 1./2-in. pipe, l i n e 84.8.

The water is supplied through

416

(h) The a f t e r c o o l e r used downstream of the component cooling system gas blowers, located i n the s p e c i a l equipment room, i s cooled by 20 gpm of treated water supplied through t h e 1-1/4-in. and returned through l i n e 874.

l i n e 873,

The o i l coolers on t h e two blowers

are a l s o water-cooled by about 10 gpm of water supplied through l i n e The water i s r e c i r c u l a t e d through l i n e 876, a l s o 1-in. pipe

875.

s i z e , which j o i n s the above-mentioned water r e t u r n l i n e from the a f t e r c o o l e r , l i n e 874, before discharging i n t o the r e t u r n header, l i n e 827. 15.2.4

Condensate System

Saturated steam a t 15 psig is condensed i n a shell-and-tube h e a t exchanger located i n t h e water room a t the s o u t h e s t corner of Bldg 7503. The condenser is cooled by cooling tower water, as described i n Section 15.2.2. The condensate leaves through a 1/2-in. s t r a i n e r and steam t r a p on the s t a i n l e s s s t e e l l i n e 801, and discharges i n t o the vented condensate storage tank, No. 1 or t o tank No. 2 through the branch l i n e 818.

The d r a i n from t h e bottom of tank No. 1, l i n e

802, and from the bottom of tank No. 2, l i n e 825, combine as the 1i n . l i n e 883, and is used t o feed the float-operated make-up valve on t h e treated w a t e r system surge tank.

Lines 802 and 803, both 1/2-in. s t a i n l e s s steel, a l s o branch from l i n e 883 t o supply makeup t o the d r a i n tank heat removal system water tanks.

15.3 Description of Equipment 15.3.1

Condensate Storage Tank No. 1

Condensate storage tank No. 1 is a v e r t i c a l , 36-in.-diam v e s s e l with an o v e r a l l height of 5 f t . a t a l l times.

The tank is vented t o t h e atmosphere

It i s constructed of 12-gage, 304 s t a i n l e s s steel,

with dished heads 3/16 i n . thick.

The t a n k s are supported by three

angle iron legs, with t h e bottom of the tank about 4 f t from the floor.

The tank has six nozzles, t h e t h r e e i n the t o p being the 1/2-

in. water supply, the 1/2-in. vent, and a 1-in. spare connection.

417

- td

There are two 1/2-in. couplings on the side f o r the water l e v e l gage. The 1-in. d r a i n l i n e connection i s i n the bottom head.

15.3.2

Condensate Storage Tank No. 2

T h i s tank i s similar t o condensate storage tank No. 1 but i s a

horizontal tank 30 i n . diam x 72 i n . long.

The c y l i n d r i c a l portion is

12-gage 304 s t a i n l e s s s t e e l with 3/16-in.-thick

dished beads.

tank is designed f o r operation a t atmospheric pressure. four nozzles a t the top: two spares.

the 1/2-in.

The

There are

i n l e t , the 1/2-in. vent, and

The two side nozzles on one end are for the water gage.

A 1-in. discharge nozzle and a 1/2-in. d r a i n are provided along the

bottom.

The tank is supported by a s t e e l cradle '78 i n . from the

floor.

T h i s tank was arranged horizontally rather than being i d e n t i c a l

t o tank No. 1 i n order t o i n s t a l l it d i r e c t l y above t h e surge tank. 15.3.3

Treated Water Surge Tank

The surge tank i s a horizontal 30-in. diam x 48 i n . long carbon

s t e e l tank designed f o r atmospheric pressure.

1/8-in.,

with 3/16-in. dished heads.

The wall thickness is

The nine nozzles include:

1-in.

feed l i n e a t the top, a 1-in chemical addition l i n e , and a 1/2-in.

Two nozzles a t one end are f o r t h e water gage and on the other

vent.

end two nozzles connect t o t h e float-operated l i q u i d l e v e l c o n t r o l l e r .

Two 1-in. pipe s i z e nozzles are a t the bottom.

The tank is supported on a cradle 30 i n . above the floor and d i r e c t l y under condensate

storage tank No. 2.

15.3.4

Cooling Tower

The cooling tower is designed t o c o o l about 550 gpm of water

from 95°F t o 85°F when t h e w e t bulb temperature i s 79°F. v a l e n t heat removal capacity is 2.75 x lo6 Btu/hr.

The equi-

The connected

cooling tower load is about 538 gpm and a possible heat load of a maxhwn of 3.94 x lo6 Btu/hr,

as was indicated i n Table 15.1.

The

tower has a capacity of 3.57 x lo6 Btu/hr when t h e w e t bulb tempera-

ture is 76°F w b t . area is 75°F.

The design wbt i n common use i n the && Ridge

...

418

The cooling tower i s a Marley Company Model 8320 "Packaged

Aquatower" with two 60-in. diam multi-blade adjustable p i t c h f a n belt driven by 5-hp, 1800-rpm, TEA0 motors.

The o v e r a l l dimensions

are 11 f t 9-1/2 i n wide x 14 f t 6-7/8 i n . long and 8 f t 8-3/4 i n . high. 15.3.5

!treated Water Cooler

The treated w a t e r cooler is a heat exchanger made available from

another p r o j e c t .

It i s a shell-and-tube type, four-pass, horizontal

heat exchanger, and is located i n the west end of the Diesel house. The shell is 28 i n . OD x 20 f t long, not including t h e heads, and has

10-in. flanged nozzles.

The 360 straight tubes are admiralty metal,

1 i n . OD, No. 18 BWG, 20 f t long, spaced on 1-1/4-in.

squares.

The

tubes are supported by f i x e d tube sheets and baffle p l a t e s of naval brass. The tube-side connections f o r the treated water are 8-in. flanged nozzles. The t o t a l heat t r a n s f e r surface is 1,885 f t 2 , t h e shell-side w a t e r

v e l o c i t y is about 0.48 f t / s e c and t h e tube-side velocity 1.75 f t / s e c , providing a n estimated o v e r a l l k a t transfer c o e f f i c i e n t of 232 Btu/hrft2-"F.156 Operating design conditions are t h a t t h e cooling tower water e n t e r s the shell a t 85°F and leaves a t 97°F. e n t e r s the tubes a t 100°F and leaves a t 90°F. 157

15.3.6

The treated water

Treated Water Circulatine: P ~ ~ D s

There are two i d e n t i c a l treated water c i r c u l a t i n g pumps, one

operating and one f o r standby.

Each is sized f o r 120% of the 96-ft

head of pressure drop estimated f o r the system158 and f o r a flow of

about 310 gpm.

The u n i t s are Peerless centrif'ugal pumps, Model 2 x 3

x 13 DL, driven by 20-hp motors.

The open-type impeller is 13 i n . i n

diam and operates a t 1,750 rpm.

The c h a r a c t e r i s t i c curves of pump

performance are shown i n Figure 15.2. Each pump and motor is mounted on a common base, about 18 x 49 in., and the u n i t is about 26 i n . high, arranged f o r t o p discharge.

419

Unclassified ORNL DWG 64-8843

180

140

' loo

8 8

40 I

Efficiency Curves

100 I

200

300

Gallons per Minute

Mgure 15.2.

Chara$teristic Curves I

- Treated Water Circulating Pumps

15.3.7

Cooling Tower Pumps

Two i d e n t i c a l cooling tower water c i r c u l a t i n g pumps are installed,

one t o serve as standby.

The u n i t s are American-Mwsh centrifugal

pumps, s i z e 4 A , Ty-pe RDM.

The pumps have 10-in. diam inclosed impellers

and are d i r e c t driven by 20-hp motors a t 1,750 rpm. pressure drop i n the system i s 53 f t of water. for 80 f t of head a t 550 gpm capacity.

curves are shown i n Figure 15.3.

The estimated

The u n i t s were selected

The c h a r a c t e r i s t i c performance

The pump and motor a r e mounted on a

comon base.

15.3.8 Steam Condenser f o r Condensate System The steam condenser is a horizontal s h e l l and t u b e type, w i t h a

carbon steel shell about 8 in. OD x 6 f t long, made available from Condensing is inside the s t a i n l e s s s t e e l tubes and

another project.

the t o t a l capacity i s about 1.2 gal/min.

15.3.9

Space Coolers

The f i v e space coolers i n the E R E processing cells are designed t o maintain the c e l l s a t temperatures below of 150°F. There are two u n i t s f o r the coolant c e l l , two i n the reactor c e l l and one i n the d r a i n tank c e l l . 15.3.9.1

Coolant C e l l Coolers.

- The two space coolers f o r the

coolant c e l l were e x i s t i n g u n i t s i n Bldg 7503.

They are external t o

the c e l l , located a t the 850-ft elevation, and connected t o the c e l l

with short ducts.

Each u n i t is mounted i n a gas-tight, 12-gage sheet

metal casing, one on the northwest side of the c e l l and the other on the southeast.

The two return ducts t o each u n i t are 12 x 19 i n . and

the discharge duct i s 23 x 28 in.

The two coolers are i d e n t i c a l and are P a n e No. 212 u n i t s with

an 8-row water c o i l and a rated cooling capacity of 250,000 Btu/hr.* The cooling load on each u n i t i s estimated t o be about 82,000 Btu/hr when the c e l l temperature is the maximum of 150°F. 159

he circulating

fans have a capacity of 3,600 cfm a t 167"F, and are driven by 2-hp,

220/440 v, 3-phase motors designed for operation a t 175°F.

The cooling

w a t e r requirements are estimated t o be about 20 gpm.

s e e aRNL Dwg f o r ART FYoject, D-KP-19040-T Rev. 2, Dec. 8, 1955.

Unclassified ORNL DWG 64-8844

100

10-in.

G I

American-Mmsh Centrifugal Pump Type RS-RD, Size 4A, 1750 rpm Enclosed 10-in. D i a . Impeller

74 H

10 4 E

5 F94 0 100

200

300

400

500

600

700

Gallons per Minute Figure 15.3.

Characteristic Curves

- Cooling Tower Water Circulating Pwnps

800

422

Table 15.3 Design Data Reactor and Drain Tank Cell Space Coolers Number of u n i t s :

In reactor c e l l

I n d r a i n tank c e l l

Design pressure

150 PSig

Required cooling water f o r each u n i t

60 gpm

Water temperature r i s e

9'F

Water pressure drop

2.1 p s i

A i r flow rate

7,400 scfm

A i r temperature drop

32.3"F

A i r pressure drop

0.6 i n . H20

Rated heat t r a n s f e r capacity*

256,000 Btu/hr (75 kw)

Fan Motor

Louis A l l i s , 3-hp, 3-phase, 60 cycle, 440 v, 1,750 rpm, Class H, t o t a l l y inclosed

Fan

Aluminum, 6 blades, 32 i n . dim

Coil

69 f t 2 e f f e c t i v e prime surface, 950 f t 2 f i n surface, red brass serpentine c o i l , 5/8-in. OD x 0.035-in. w a l l tubes, 0.010 i n . f i n s mechanically bonded t o tubes

Approximate weight

1,600 lbs (with water)

Dimensions

About 50 i n . x 29 in. x 44 i n . high

*Ehtering a i r assumed a t 150°F.

423

The reactor 15.3.9.2 Reactor and Drain Tank Cell Space Coolers. and d r a i n tank c e l l s are estimated t o require the removal of a t o t a l of

about 500,000 Btu/hr t o maintain the c e l l temperature below 150°F.

Two

space coolers are used i n the reactor c e l l and one i n the drain tank c e l l . The u n i t s are i d e n t i c a l and are Young Radiator Company Model 55, modified f o r d i r e c t drive and i n s t a l l e d t o f a c i l i t a t e maintenance using

remotely-operated tooling. The water tubes and headers are backbrazed t o reduce the likelihood of water leaking i n t o the c e l l . The treated water supply and r e t u r n l i n e s are connected by ring-joint type flanges, which a r e monitored f o r Leakage. Design data f o r the coolers are l i s t e d i n Table 15.3. 15.3.10 Piping Valves and Appurtenances 15.3.10.1 P i p i x .

- All w a t e r system piping-located outside the

containment c e l l s is sched 40 black steel, ASTM A-53. Pipe and fittings above 1-1/2-in. pipe s i z e are butt-welded, and the fittings are ASTMA234 Grade B. Smaller pipe and fittings are threaded; the f i t t i n g s are 150-psi black malleable iron. Condensate piping is 304 s t a i n l e s s s t e e l w i t h standard weight screwed f i t t i n g s . A l l water system piping inside the c e l l s is 304 s t a i n l e s s steel, c

sched 4 0 , w i t h butt-welded ends. Flanges are either 150-psi or 300 p s i weld-neck, r i n g - j o i n t flanges, depending on service and location. A l l of these j o i n t s are leak-detected. Valves of 2-1/2-in. size and over have 15.3.10.2 Valves. flanged connections. The gate valves are 125-psi Ferrosteel wedge valves w i t h bronze trim and outside screw and yoke, Crane No. 465-1/2.

The globe valves are Ferrosteel w i t h joke bonnet, bronze t r i m , Crane No. 351. Bronze trim is a l s o used i n the 125-psi Ferrosteel swing check valves, Crane No. 363. Valves used i n piping 2 i n . and smaller have screwed ends. The gate valves are 125-psi bronze valves with rising stems, Crane No. 430-UB. Globe valves are 350-psi bronze, Crane No. 14P. Ekcept as noted below, the check valves are 125-psi bronze, Crane No. 34. The check valves i n l i n e s 836, 838, and 840, which supply treated water t o the reactor and drain tank c e l l space coolers, are Circle Seal

1 r

424 Model 23OB-16 PP, 0.5

- 1 p s i . The check valves i n l i n e s 830 and 832,

Ld *

supplying treated water t o t h e f u e l and coolant s a l t pump motors, are Circle S e a l Model 23OB-8 PP, 0.5 - 1 p s i .

These s p e c i a l check valves

prevent back flow if the block valves i n these water supply l i n e s a r e closed by detection of r a d i o a c t i v i t y i n the r e t u r n water stream. The pressure relief valves used i n r e t u r n water l i n e s 837, 846,

841, 847, etc., are F a r r i s Series 1475, 1/2-in. s i z e , set a t 100 p s i . The pressure relief valve i n line 855 is i d e n t i c a l but set a t 20 p s i t o p r o t e c t the thermal s h i e l d from excessive pressure.

The air-operated control valves are described i n P a r t 11.

15.3.10.3

Backflow Preventers.

- The potable water system is

protected from contamination due t o reverse flow by a 4-in. backflow preventer i n l i n e 890. The cooling tower system i s a l s o protected f r o m contamination f r o m the l i q u i d waste system by a similar, b u t 2-in. pipe size,backflow preventer i n l i n e 819. Both u n i t s are Beeco Model 6 C, reduced-pressure, backflow preventers, as shown i n Figure 15.4.

The u n i t s operate on t h e principle

t h a t two spring-loaded check valves, "A" and "Bff i n Figure 15.4,

(with

8 p s i springs) are i n series with a spring-loaded diaphragm-operated relief valve, "C", i n between. The upstream pressure, "D", a c t s on one side of the diaphragm and the intermediate pressure, "E", and a 4-psi spring, a c t on the other.

If the supply pressure drops, or the

intermediate pressure increases i n a condition tending t o c r e a t e backflow, the diaphragm-operated relief valve opens t o discharge the water t o drain.

The 4-in. potable water valve, BFP-890-1, r e l i e v e s

water t o the building sump. The 2-in. valve i n the l i q u i d waste c e l l , RFP-819, discharges the relief water t o t h e waste tank. The capacities of the two valves a t various pressure heads are shown i n Figure 15.5. 15.3.10.4

Strainer.

- The suction l i n e t o t h e treated water

pumps is equipped with a 3-in. Schute and Koerting duplex s t r a i n e r . The u n i t consists of two 24-in. s t r a i n e r baskets with a plug valve t o s e l e c t the s t r a i n e r i n use.

While one s t r a i n e r i s i n service the

other can be removed f o r cleaning. brass s t r a i n e r baskets.

The u n i t has a c a s t iron body with

425

426 - ._

Unclassified ORNL DWG 64-8846

32 24

a 0

400

200

Flow Rate

- gpm

600

a. Valve BFPW-1

MRF=l6om

32 24

l6 8 0 0

Flow Rate

120

- gpm

b. Valve BFP-8l9

FYgure 15.5.

Capacity of Back-Flow Preventers i n Water System

4 +

427

u P

15.3.11

Treated Water F i l t e r

The f i l t e r i n the treated water circulating pump discharge, l i n e

829, is rated a t 75 psig and 120°F t o remve p a r t i c l e s of 30 microns

i n diam and greater from a flow of a minimum of 380 gpm. The maximum pressure loss .due t o flow through the u n i t iS I5 p s i . The i n l e t and o u t l e t connections are 6-in. pipe s i z e , sched 40. A by-pass is incorporated t o allow cleaning of the u n i t without disrupting the flow of treated water.

(Rochester).

The f i l t e r is manufactured by tk Dollinger Corporation

428

16. COMPONEXC COOLING SYSTEMS The upper portion of the fuel circulating pump bowl and the control

rod drives are cooled by streams of gas i n order t o avoid excessively highly operating temperatures. The freeze valves, the seals a t the reactor access nozzle, etc., are cooled by gas t o maintain the s a l t well below the melting temperature t o assure a frozen s a l t seal. The component cooling equipment is arranged In two separate systems: (1)a circulating gas loop f o r cooling equipment located in the reactor and drain tank c e u s , and (e), an air supply system f o r cooling freeze valves i n the coolant and f u e l processing cells. 16.1

16.1.1

General Description and Layout

C i r c u l a t i n g Gas S y s t e m

Cell atmosphere gas (%$ N2, 59 02) is circulated by a 75-hp, 885-cf'm

positive-displacement blower sealed i n - a 6 f t diam x 8 ft steel tank located i n the special equipment room. (An identical blower unit I s i n standby). The blower discharges through a vertical, 8-in.diam x 9-ft long, shell and tube, water-cooled heat exchanger, also located i n the special equipment room. The gas, now a t about 150°F and 21.3 psia, flows t o a 6-in. distributing header i n the reactor cell, where streams are taken from it t o cool the equipment listed i n Table 16.1. The gas passes over the various surfaces t o be cooled and then mingles with the c e l l atmosphere. The 10-in. blower suction connection is made t o the 30-in. d i m containment ventilation system pipe, l i n e 930, where it passes through the special equipment mom.

Each gas blower has sufficient capacity t o also be used f o r evacuation of the reactor and drain tank cells. I n t h i s operation, a portion of the blower discharge is diverted t o the containment ventilation system, t o be monitored and f i l t e r e d before discharge f r o m the stack. Due t o c e l l inleakage, o r t o various purge gas streams t h a t may be introduced, a periodic, o r perhaps continuous, evacuation w i l l be required t o maintain the c e l l s a t the desired 12.7 psi& operating pressure.

429

Table 16.1 Gas-Cooled Components

Component Cooled

Gas Supply Line

Apprsx. Gas Flow Req'd. SCm

88 Fuel pump bowl .. 4

0-4QO

1-15 1-15

FV-104 i n itrain tank c e l l FV-105 i n drain tank c e l l FV-106 i n drain tank c e l l FV-107 i n drain tank c e l l FV-lo8 i n drain tank c e l l FV-109 i n drain tank c e l l Three control rod drives FV-lo3 i n reactor c e l l160 Off-gas l i n e 52% Graphite sampler - nozzle Outside of reactor access nozzle Inside of reactor access nozzle *A secondary function.

1-15

1-15 1-15 1-15 915

919

1-114

25 -75

960

3 3/4 314 314

800

961 962 963

The primary purpose I s t o regulate system pressure through PdCV 960 and t o return the gas t o the reactor and drain tank cells.

430

I n estimating the gas flow rates required, it was assumed that not a l l freeze valves would require a high rate of cooling a t the same time. I n general, no gas flow measurements w i l l be made during operation of

ti w

the reactor, the flow rates simply being adjusted t o maintain the equipment a t the proper operating temperatures. 16.1.2 Cooling A i r Supply A i r f o r cooling the freeze valves i n the coolant and fuel processing i

c e l l s i s provided by a 5-hp positive-displacement type blower of 60 scfm capacity, located i n the blower house a t the southwest corner of Bldg 7503. A i r i n the 3-in. discharge pipe is divided t o cool the equipment l i s t e d i n Table 16.2. After blowing on the flattened sections of process piping t h a t serve as freeze valves, the air i s then carried off by the c e l l P

ventilation ducts. 16.2

Flowsheet

The flowsheet f o r the gas blowers and cooler located i n the special equipment room i s included on the f u e l system process flowsheet, Figure Other portions of the gas circulating 5.3 (ORNL Dwg D-AA-A-40880). system are shown on other process flowsheets t o be mentioned subsequently. The c e l l atmosphere gas blower (95% N2, 54 02), CCP-1, draws gas from inside i t s 6-ft-diam x 8-ft high containment tank. A 10-in. sched 40 stainless s t e e l pipe, l i n e 923, connected t o the bottom of the tank, joins a similar suction l i n e t o the alternate blower, CCP-2, (line 92), and as a 10-in. pipe connects the short distance t o the 30-in. containment ventilation pipe, l i n e 930.

The suction lines contain instrumentation

f o r temperature indication and each has a hand valve t o permit switching of service between the blowers. The normal operating pressure i n a blower containment tank, i.e., the blower suction pressure, i s 12.5 psia and the gas enters a t about 15OoF. The D-hp blower drive motor i s cooled by the gas flow through the tank. The gas blower CCP-1 discharges a t about 21.3 psia and 320°F through

a 6-in. sched 40 stainless s t e e l pipe, l i n e 916, which passes through the bottom head of the containment tank. The portion inside the tank contains a flexible connector, a pressure-relief valve connection, and a check valve

. ~

431

Table 16.2 Air-Cooled Components

Component Cooled

A i r Supply Line

NO FV-204 i n coolant c e l l FV-206 i n coolant c e l l FV-ll2 i n f u e l proc. c e l l

FV-111 i n f u e l proc. c e l l FV-IlO i n f u e l proc. c e l l

Approx. Air

Pipe Size

F~OW

ReqVL

1-15 scfm 1-15 S C F ~ 1-15 scfm 1-15 S C ~ 1-15 scfm

906 907 924 929

969

432 i s located inside the tank and vents t o it when the differential pressure exceeds l2 psi. Lubricating o i l from the blower suqp i s circulated by a gear pmp driven by the blower shaft, the o i l flowing through 6t watercooled stainless steel heat exchanger and o i l f i l t e r before returning t o the blower bearings. A pressure relief valve on the o i l Une i s set at a differential pressure of 12 psi t o vent the o i l t o the blower sump in event the heat exchanger or f i l t e r becomes clogged. The o i l pressure i s monitored by a pressure transmitter located i n the o i l return line f r o m the f i l t e r . The alternate gas blower, CCP-2, i n an identical arrangement discharges Into the 6-in. line 921, which Joins the above-mentioned discharge line f r o m blower CCP-1, before entering the gas cooler. The compressed gas enters the shell side of the gas cooler a t about 320- ana leaves a t about 150°F. The tube side of the horizontal shelland-tube heat exchanger i s coaled by a flow of about 20 gpm of 90°F treated water, supplied through l i n e 873 and leaving through line 874. The i n l e t and outlet gas lines have thermocouples t o permit heat balances t o be made and an estimation of the gas flow rate. The gas leaves the cooler through the 6-in. sched 40 stainless s t e e l line 917. A 1-1/2-in. sched 40 stainless steel pipe, line 565, branches f r o m line 917 inside the special equipment room, and leads t o the vent house. As shown on the containment ventilation system flowsheet, Figure 12.1, (ORNL Dwg D-AA-A-40883), line 565 connects t o line 571 i n the vent house, and continuing as line 565, i s provided with two GM probes t o monitor for radioactivity, RIA-565, and a block valve HCV-565, actuated by the monitor. A 1/2-in. by-pass line, 569, leads through a wet flow meter, t o a sampling point, and through a f l o w totalizer and indicator, FqI-569, back into line 565. The hand valves i n the by-pass line, 569, and in line 565, are used t o regulate the c e l l pressure. Line 565 discharges into line 927 t o pass through the roughing and absolute f i l t e r s before release from the ventilation system stack. This arrangement for venting a portion of the blower discharge t o the atmosphere i s used t o evacuate gas from the reactor and drain tank cells t o maintain them at the desired operating pressure of about 12.7 psia. A hand valve In lrne 565 i s used t o regulate the c e l l pressure.

Gd I

cl c

433

Continuing w i t h the conpressed gas line 917, t h i s 61ino sched 40 pipe passes through a penetration into the reactor cell, there the pipe material thenbecomes carbon steel, and serves as a header for the several com,ponent cooling system gas supply lines listea in Table 16.1. This table lists the line sizes and flow rates i n each of the eight branches. A l l eight of the gas sugply lines, except line 920, contain a i r operated valves f o r controlling the ga$ flow. Line 920 i s a 2-in. sched 40 carbon steel pipe passing through the 36-in. d i m opening between the reactor and drain tank cells and then through a penetration in the drain tank c e l l w a l l t o supply a valve manifold station located i n the north electric service area. Here, through six throttle valves, as shown i n Figure 6.1 (0"L D-AA-A-40882), lines branch off t o supply cooling gas t o freeze valves i n the drain tank c e l l on lines 104, 105, and 106, 107, 108 and 109. (The freeze valves on lines 107, 108 and lo9 are shown on the fuel processing flowsheet, Figure 6.2

(ORNL Dwg D-AA-A-40887) The air-operated valve in line 960, pdcv-960, i s controlled by a

differentid-pressure c e l l connected betweenllines 917 and 923, i.e., between the gas blower suction and discharge lines. This valve varses the flow through line 960 t o =@ate the component cooling gas supply pressure t o a relatively constant va.lue irrespective of the rate of use a t various freeze valves, et@. The 3-in. line 960 discharges into the reactor c e l l in the annular space between a 44% length of 10-in. sched 10 pipe and the &-in. portion of the off-gas line 522, at the 831-ft elm near the c e l l wallo a i s arraJlgement helps cools the leaving off-gaE: e t r e m . , The 5-hp, ~ o - s c ~positive-displacement , type blower, CCP-3, supplyiq conponent cooling sir t o the coolant and processing cells is located i n the blower house. As shown on the coolant system flowsheet, Figure 9. ( O m Dwg D-AA-A-40881), air is drawn from the blower house through a f i l t e r , The blower discharge is a +in0 sched 40 carbon s t e e l pipe, line 906, which is provided with a check valve and safety block valve ESV-gotjC. A pressurerelief valve, set a t 10 paig, vents t o tbe blower room. An air-operated

L. 4

434

valve, pCV-906B, in 8 branch line from 906, also vents t o the atmosphere, and is controlled by a pressure transmitter in Line 906, PICA-906B, t o regulate the a i r supply pressure. An alternate air supply ISprovided through line 967, a l-in. sched 40 pipe which connects t o line go6 down stream of the check valve CV-906. Line 967 supplies a i r from the service a i r system through a 1-in. check valve, pressure regulator, m-967, and a stop valve. bout 17 sc~mof air is withdrawn from line 906 upstream of H C V - ~ B t o supply the fuel processing ceU freeze valves through a 1-1/4-in. header, line 924. As shown in the flowsheet, Figure 6.2 (ORmL Dwg D-AA-A-40887), before entering the fuel processing cell, line 924 branches into the 3/4-in. steel pipe lines 929, 969 and 924, t o supply air t o the! freeee valves FV-ll0 and FV-U2, respectively. Line 906 continues a s a 1-1/4-in. sched 40 pipe t o enter the coolant cell. A 3/4-in. pipe size branch, line 90'7, with hand-operated regulating valve, supplies 1-15 ecfm of a i r t o the freeze valve FV-206. Line 906 continues 8s a 3/4-in. pipe t o supply 1-15 scfm t o the freeze valve FV-204. The discharged cooling air mingles with the air in the coolant c e l l and is vented through the ventilation system. 16.3

41 T

~ e s c r i p t i o nof Equigment 5

16.3.1 Gas Blowers CCP-1 and CCP-2 anb Containment Tanks The positlve-disglacement type blowers used t o circulate the c e l l atmosphere gas (95s ,N 5s 02) are Roots-Connersville 'type RAS blowers, size 10 x 15. Each will deliver 885 scf'm at 12.7 psia and 150°F suction conditions and a t 21.3 psia discharge pressure. The discharge gas temperature is estimated t o be about 320°F. Under these conditions the brake horsepower requirement is 70.3 bhp and the speed 900 rpm. The blowers are driven thmugh a V-belt drive by E-hp, 1,200-rpm, kkO-volt, squirrel cage induction motors, Type F, mounted about 4 ft above the blawers on a common channel-iron framework. (See O m Dwg EdJ-C-41472). The blower bearings, seals and gears are pressure ltibricated and cooled by punsring o i l from a sump in the blower housing through a stainiess steel, water-cooled heat exchanger, through a f i l t e r and back t o l

435 the bearings and seals. Excell o i l i s by-passed through a relief valve and vented t o the o i l smp. The o i l pur@ i s a Worthington gear puxrp, !fype 3 G U T , driven by an extension of the blower shaft. Since there could possibly be gas leakage a t the blower shaft seals, each blower is contained i n a steel tank, which is, i n effect, an extension of the reactor containment, an8 was deeigned accordingly. Each blower was mounted i n a separate tank so that one could be i n service while the other i s open f o r maintenance. Ets& tank i s 62 in. OD x 96 in. highI overall, with 5/16-in0 wall, and upper and lower ASME torospherical heads 3/8-in. thick. The height of the cylindrical portion between the top head weld and the bottom closure flange i s 60-7/8 in. The tanks are constructed of carbon steel, SA-201. Each was designed f o r 40 psig internal pressure, 7 psig external pressure a t Nuclear Case 200*F, i n accordance with the ASME Code Section VIII~~, l270N and l272N. The vessels were stress relieved a t 1100°F and hyiirostaticaUy tested a t 60 psig. 1

The upper head of each tank i s welded in place and the lower head is bolted t o the tank with an ASME Grade 350, Class LFl, raised-face flange joint, using 60 steel bolts, 1-3/4 in. x 6 in. long, and a 1/8-inetbick "Viton" gasket. The top head i s provided with three l i f t i n g lugs t o f a c i l i t a t e removal for mintenance. The tank is supported by four 3-in. pips legs about 28 in. long welded t o reinf'orcing pads on the bottom head. The 10-in. sched 40 stainless steel suction line is welded t o a 10-in. carbon steel nozzle welded into a reinforced opening a t the centerline of the lower hea8. m e gas is drawn into the interior of the tank and in passing t h r o w it t o the blower suction opening helps cool the drive motor. The 6-in. blower discharge is flanged t o the 6-in. sched 40 discharge nozzle welded into a reinforced opening in the lower head. A =-in. bolted-fbnge inspection nozzle i s located on the side of the tank about 14 in. above the vessel closure f-e ana i s used for checking the o i l level, changing the oil, f i l t e r s , etc. The electrical leads $01" the motor are brought through a special sleeve i n the lower head using copper-lsheathed, mineral-insulated, 3-conductor No. 4 cable.

436

l6.3.2 Air Blower, CCP-3 The blower f o r furnishing cooling a i r t o the freeze flanges i n the coolant and fuel processing cells is located in the blower house at the southwest corner of Bldg 7503. It is a Sutor built, Model 44, rated a t 60 scfm of a i r a t 8 psig discharge pmssure, when operating at 1,510 rpm. It is driven by 5-hp, 1,800-1-pm electric motor through a V-belt h i v e . The timing gears are oil-spXash lubricated and the bearinge and seals are grease-lubricated. The basic blower design i s similar t o the CCP-1 and CCP-2 gas blowers described above.

16.3.3

Gas Cooler, GC.

The 320- compressed gas leaving the gas blower, CCP-1 or CCP-2, i s cooled t o about 150- in a horizontal, shell-and-tube, stainless steel all-welded, heat exchanger located in the special equipment room. The exchanger is cooled by a flow of about 20 gpm of treated water circulating through the tubes in a two-pass arrangement. The shell is 8-in. sched 40 pipe and about 9 f t 5 in. long. Two 6-ixi. sched 40 gas nozzles are butt welded t o the shell t o pravide a single pass f o r t h e gas flow through the shell. There are 56 tubes fabricated of 5/8-in. No. 16 BWG seamless 304 stainless steel, mounted on l3/16-in. triangular pitch. 2 The tubes are The effective heat transfer surface is about 73 f t rolled into the tube sheet and seal-welded. The tubs sheets are welded t o the shell. The heat remval capacity i s estimated t o be about 181,000 Btu/hr and the pressure loss due t o flow on the shell side is about 0.5 psi.

1603.4 valves Valves used i n the component cooling systems are listed in Table 16.3. All valves used in the gas circulating system outside of the reactor c e l l are in effect p a r t of the reactor containment and are 304 stainless steel or Monel. The valves inside the cells are steel, with either threaded or flanged connections. Threaded valves are back-welded. AU. valves have flanged disconnects in the horizontal plane in the lines a short distance fromthe valve t o facilitate remote maintenance procedures. Steel valves are used i n the sir distribution system.

= I

437

Table 16.3 Component Cooling System Valves

Valve

Size

(in. 1

Location

Material

Seal

Vent House Vent House Vent House Vent House Vent House

Monel

~ Bellows S O CWeld Packed Bo Weld

Vent House

Brass Monel Brass Monel

Vent House Vent House Vent House Vent House Vent House Reactor C , Blower H.

Brass Brass Brass Bmss

CDC CDC No, ESA No. ESA

S.S.

Steel Steel Steel Steel S.S.

NO. ESA NO, ESA No. ESA NO, ESA

S.S.

Steel

SER SHi

S.S.

s.s,

S.S.

s.s,

Steel Steel

SER

S.S.

SER

Steel

SER SER

S.S.

Fpc

Steel Steel Steel Steel Steel Steel Steel Steel Steel

RC RC

RC RC RC Blower E. Fpc

FFC

* 0.188-1n,-Biam

s.s,

orifice

* OaK5-in,diam orifice V - - H a d Valve CV

S.S.

--Checkvalve Air-operated Control Valve

HCV

Connection

Inst.

Msm

SMD

Packed Threaded Bellows SOC. Weld Threaded CVS6B SMD Bellows Soc. Weld Threaded CVS6A Packed Threaded Packed Threaded Packed Threaded Threaded cvs7 Packed Flanged 32 Packed Threaded 33 Packed Threaded 33 Packed Threaded 33 Bellows B. Weld 53 Bellows B, Weld 53 Bellows B. Weld 53 Bellows B. Weld 53 Bellows B. Weld 53 Bellows B. Weld 53 Packed Threaded 46 Packed B, Weld Flanged Packed Threaded 36 Packed B. Weld Flanged Packed Bo Weld Packed B. Weld Packed Threaded 33 46 Packed Threaded Packed Flanged 47 46 Packed Threaded Packed Threaded 46 46 Packed Threaded Packed Threaded Packed Threaaed 33 Packed Threaded 33

23 3 3 3 3 3 3 3 3 3

-17 . -

2.2

. . I

PCV

2.2

90. 2.2 2 a2 2.2

3 3

Pressure Control Valve Soco Weld Socket Weld €3. Weld Butt Weld

438

The two gas blowers, CCP-1 and CCP-2, have 10-in. valves i n the suction lines and 6411. valves in the discharge lines t o enable service t o be transferred from one t o the other. These four valves meet the requirements of the ASA B 3l.lPressure Piping Code and Nuclear Case N10. They are butt-welded, cast-body, 304 stainless steel gate valves with ring seats, and 115th the stemback-seating on a teflon seat when the valve is open.

16.3.5 Piping Piping i n the gas-circulating portion of the corqponent cooling system located outside the reactor c e l l is 8 part of the reactor con-

tainment and is constructed of reactor-grade materials. A l l piping I s 304 stainless s t e e l pipe, seamless or welded Pipe which has been fully

x-rayed. Piping inside the cells is sched 4 0 carbon steel w i t h socket welds at the joints.

The air distribution system uses sched 4.0 carbon s t e e l pipe with

threaded joints.

439

17. CONTAINMENT 17.1 General Design Considerations During operation, maintenance, and in case of an accident, it i s required t h a t the containment be adequate t o prevent escape of multicurie amounts of radioactivity t o the surrounding area. The containment must also prevent the release of dangerous amounts of other hazardous materials ,

and, in general, serve t o protect personnel and equipment. Any equipment which contains, o r could contain, multicurie amounts of radioactive material must have a minimum of two barriers t o prevent i t s escape 1 6 ' During operation of the MSRE the primary containment consists of

the walls of the components and the connecting piping.

The reactor and

drain tank c e l l enclosures provide the secondary containment during operation. These c e l l s normally operate at sub-atmospheric pressure t o assure that any leakage i s i n w a r d and t h a t the r a t e can be continuously measured.

The controlled ventilation areas i n the high bay and various cells, a s described in Section 13, constitute a third barrier t o the escape of

activity during normal operation of the reactor. Air i s drawn through these sub-atmospheric-pressure enclosed areas, passed through absolute filters, and monitored f o r radioactivity before discharge from the ventilation system stack located south of Building 7503. When the reactor o r drain tank c e l l s are opened for maintenance, air flow through the openings at velocities in excess of 100 fpm i s subs t i t u t e d a s the secondary barrier. If the primary piping i n the c e l l is opened f o r maintenance, then the air flow through the c e l l opening becomes the primary barrier and the controlled ventilation area becomes the secondary containment. In taking samples of f i e 1 salt from the bowl of the fuel pump through the s q l e r - e n r i c h e r system described in Section 7, sealed containers cons t i t u t e the primary and secondary containnent.

In the hypothesis of the maximum credible accident (see past V), i n which it is assumed that hot fuel s a l t mixes with the water in the c e l l s t o generate steam, the t o t a l pressure i n the containment vessels could exE, 161 A ceed the design value of 40 psig and 26Q0F, i f not controlled.

440

vapor condensing system is provided which can rapidly condense the steam and also retain the non-condensible gases.

b t

During normal operation the atmosphere in the reactor and drain tank c e l l containment enclosures is maintained as an inert mixture ( > 94$ I?,, >5$ 02) t o eliminate hazards due t o combustion of i n f h b l e materials in the cell, such as the o i l in the f u e l circulating pmxp lubrication system. The entire primary system is of all-welded construction with a l l flanged joints leak detected, except at a f e w less vulnerable locations where autoclave f i t t i n g s are used. Pip lines which pass through the c e l l

w a l l s t o connect t o the primary system have check valves and/or air-operated block valves w h i c h are controlled by radiation monitors or pressure switches sensing a r i s e in c e l l pressure. The portion of t h i s piping outside the cell, between the c e l l wall penetration and the check o r block valve, and the valves themselves, are enclosed t o provide the required secondary containment. llhese enclosures are designed t o be capable of withstauding the same maximum pressure ( 4 0 psig) as the reactor and drain tank cells, except in some special cases where containers vented t o the ventilation system are used. A l l service U s e s penetrating the secondary containment, that is, the c e l l w a l l s , have check valves o r air-operated block valves which close on detection of abnormal radioactivity or abnormally high c e l l pressure, or are parts of completely closed piping systems. 1'7.2

Reactor and Drain Tank Cells

During normal operation of the reactor, a l l f u e l salt w i l l be in equipment o r piping contained in the reactor and drain tank c e l l s .

The

reactor containment vessel i s 24 f t ID x 33 f t in overall height, w i t h hemispherical bottom and flat top, as described in Section 4.3.1. The drain tank c e l l is rectangular, with inside dimensions of 17 f t 7 in. x 21 ft 2-1/2 in. x 20 f t 6 in. high, and is described in Section 4.3.2.

The two c e l l s are interconnected by an open tunnel, operate a t the same pressure at all times, and w i l l withstand internal pressures in excess of 40 psig. Both are sealed and operate at 12.7 psia t o prevent outleakage of airborne contaminants. The negative pressure is maintained

441 by the gas blower in the component cooling system, described i n Section 16.

17.2.1

Cell leak Rate

The allowable leakage from the reactor and drain tank c e l l s i s taken as 1% of the c e l l volume per day at the conditions encountered i n the postulated maximum credible accident.

c e l l pressure of 40 psig.

This mounts t o 8*2 l i t e r s l h r STP at a

For the capillary type flaw which occurs through

very small openings, the leak rate i s a direct function of the c e l l absol u t e pressure. A t a c e l l pressure of 12.7 psia, the normal operating pressure, the leak rate equivalent t o the maximum allowable i s 0.42 scfh. 17.2.2

Cell Atmosphere

The c e l l atmosphere i s N2 containing less than !5$ 02, the l o w oxygen

content serving t o eliminate the hazards of explosions due t o possible leakage of o i l from the f u e l salt circulating pump lubricating system. Nitrogen is added t o the c e l l as needed t o W e up f o r air inleakage. The leak r a t e into the cell$ i s determined by: (1)observing changes i n abso-

l u t e pressure ( a f t e r compensating f o r changes in c e l l air temperature), ( 2 ) observing the change in differential pressure between the c e l l s and a temperature-compensating reference volume located inside the cell, and (3) observing the changes i n oxygen content of the c e l l atmosphere. A t the 12.7 psia no& cell operating pressure, and w i t h a leak r a t e of 0 . k scfh, the required nitrogen purge rate i s 1.5 scfh. The nitrogen is normally supplied from a bank of two cylinders located i n the northwest corner of Building 7503 at the 840-ft elevation. The nitrogen enters the c e l l through the bubblers used f o r measuring the liquid level i n the c e l l sump, as mentioned in Section 14.2.

maintenance, approximately 26,000 scf of nitrogen gas is required t o lower the O2 content in c e l l t o 5%. This large volume of gas w i l l be added through a temporaxy line from trailer-mounted nitrogen cylinders t o the sump j e t supply lines.

' I

After the c e l l s have been opened for

F A

a 2

17.2.3 Penetrations and Methods of Sealing piping and wiring penetrations through the c e l l walls were given careful design study t o reduce a s much as possible t h i s sowce of gas leakage. !Che penetrations through the reactor containment vessel w a l l are listed i n Table 4.1 and those in the drain tank c e l l are shown in Table 4.2. The outside of all process piping entering the c e l l is welded at the penetrations. All e l e c t r i c a l leads passing through the c e l l w a l l s are magnesium.. oxide-filled copper sheaths. The outside of the sheaths are sealed t o the 3/4-in. pipe penetrations by two compression-type fittings, one inside and one-gutside the cell. The ends of the sheaths which terminate inside the c e h s are sealed at the disconnect by glass-to-metal seals. The ends which terminate outside are sealed by standard mineral-insulated cable-end seals, a s manufactured by the General Cable Company. (The seal i s formed by compressing a plastic insulating material around the wires. ) All thermocouples have Fiberglas insulated leads i n multi-conductor, sheathed cables. !&e outside of the sheaths are sealed t o the 3/4-in. pipe penetrations inside and outside the cell, using s o f t solder. The ends of the sheaths terminating inside the c e l l s are sealed at the disconnect by glass t o metal welds. The ends of the cables outside the c e l l s are terminated in epoxy sealed headers. The headers can be pressurized t o test for leaks. The outside of a l l instrument pneumatic signal lines and instrument air lines are sealed to the 3/bin. pipe penetrations by two compression type fittings, one inside and one outside the c e l l . Each of these U s e s contains a block valve located near the c e l l w a l l , the valves closing automatically i f the c e l l pressure becomes greater than atmospheric. Methods of sealing certain lines require special mention, as follows: a. Cell ventilation l i n e 930 contains two 30-in. motor-operated butterfly valves in series, as described in Section 13. These valves are s t r i c t l y supervised t o assure that they remain closed during reactor oper€ition.

b. The component cooling system blowers described i n Section 16 are sealed in containment tanks t o guard against loss of gas at the shaft

seals

- The c e l l evacuation line 565 contains a block valve, HCV-565, C.

which automatically closes i n event radioactivity is detected in the line

by the monitor, RE-565.

-d. The air supply lines 332 and 342 f o r the c e l l sumps contain s o f t seated check valves. e. Jet discharge l i n e s 333 and 343 from the sumps each contain two block valves in series, FCV-333-A and B, and FCV-343-A and B, which automatically close i f the c e l l pressure becomes greater than atmospheric. A 1/2-in. connection is provided between the valves t o test them f o r leak tightness f. The Fuel sampler-enricher system is interlocked t o prevent a direct opening t o the atmosphere, as described in Bection 7. All helium supply lines contain soft seated check valves. 6. The steam condensing system used in conjunction w i t h the drain tank heat removal system i s a closed loop except f o r the water supply lines, which contain soft seated check valves, and the vent, which relieves t o the vapor condensing system, t o be described subsequently. h. A l l cooling water lines entering the c e l l have soft seated check valves o r block valves controlled by radiation monitors. All lines leaving the cells are provided with block valves controlled by radiation monitors i. The f u e l p u p lubricating oil system is a closed circulating loop. Strict supemision is provided during additions of o i l o r o i l sampling t o assure that the containment is not violated. JI. The leak-detector system i s closed and operates at a higher pressure than i n the reactor process systems. k. Several differential-pressure c e l l s and pressure transmitters are located outside the c e l l s but are connected t o process piping inside through instnunent tubing. The instrument lines are doubly contained. The dialphra@pl of the DP c e l l provides primary containment. The instrument expansion charriber designed f o r an internal pressure cases are vented t o of 50 psig t o provide the secondary containment. The cases also serve as an atmospheric reference pressure f o r the transmitters.

444

-1. A l l helium supply lines connected t o process equipment in-

side the c e l l s contain one or more soft seated check valves. m. The f u e l pump bowl off-gas line 522, between the c e l l w a l l and the instrument box i n the vent house pit, i s 1/4-in. pipe contained

within a 3/4-in. pipe. 16* The drain tank off-gas l i n e 561, between the c e l l w a l l and the instrument box i s a 1/2-in. pipe enclosed within a 1-in. pipe. Lines 522 and 561 share a common 3-in. conta3nmen-t pipe between the instrument box and the valve box attached t o the charcoal bed penetration.

The charcoal bed p i t , instrument box, valve box and the annulas spaces around the off-gas pipes, are vented t o the containment ventilation system. The off-gas lines f r o m the charcoal beds have a common block valve, HCV-557C, w h i c h closes on detection of radioactivity i n the line.

-n. The coolant salt lines 200 and 201, penetrating the reactor c e l l wall., are part of a closed circulating system. Section 8.5.

They are described i n

The stresses i n the relatively thin containment vessel w a l l due t o the various penetrations were studied and found t o be within allowable values, w i t h the maximum stresses occurring i n the nozzles. 12, 163, 164

17.3 Vapor Condensing Systexn* An accident can be conceived in which hot f i e 1 salt and the water

used t o cool equipment inside the c e l l s become mixed and generates steam t o pressurize the reactor and drain tank cells. (See the Analysis of

Hazards, Part V), A vapor condensing system i s provided t o prevent the steam pressure from rising above the 40 psig allowable pressure f o r the cells, and t o retain the non-condensible gases.

This equipment, con-

sisting primarily of a v e r t i c a l water tank and a horizontal gas storage

tank, is located about 60 f t from the southeast corner of Building 7503# as shown in Fig. 3.2,

The general arrangement i s sham schematically i n

Fig- 17.1.

*The vapor condensing system i s sometimes referred t o in the MSRE literature as the pressure suppression system.

L+ k

i d

UNCLASSIFIED ORNL LR- DWG. 87162 R 2

40 ft FROM REACTOR BLDG.

SPE:CIAL EQUIPMENT ROOM IN REACTOR BLDG.\

Z-in.-DIAM. VENT LINE TO FILTERS AND STACK GROUND ELEV. 851 ft 6 in/

ELEV. 8 5 8 f t I

/ IO-ft-DIAM. x 66 ft-LONG 3900-ft

RELIEF LINE

BURSTING D

VACUUM RELIEF VALVE

bO-in.-DIAM. VENT DUCT FROM REACTOR CELL

I O - f t D1AM.x 2 3 - f t HIGH' 1 2 0 0 f t 3 WATER

1800 ft3

VAPOR CONDENSING TANK

'BUTTERFLY VALVES

Fig. 17.1.

f t.

D i a g r a m of MSRE Vapor-Condensing System

ELEV. 0 2 4 f t

446 (The method of handling steam t h a t might be generated beneath the reactor c e l l containment vessel i f hot f u e l were s p i l l e d t o the bottom of t h e c e l l i s discussed i n Section 4.3.1.) As sham on the off-gas system and containment v e n t i l a t i o n process

flowsheet, Fig. 13.2 (ORNL drawing D-AA-A-40883),

and on the layout draw-

ing, ORNL D - K K - D - ~ & ~ ~ , a 12-in. sched-40 s t e e l pipe, l i n e 980, branches from the 3O-in.-diam c e l l ventilation pipe i n the s p e c i a l equipment room upstream of the two b u t t e r f l y valves, HCV-930-A and HCV-930-B. 165 Inside the s p e c i a l equipment room, l i n e 980 contains a 10-in. rupture disk having

a bursting pressure of 20 psi, and i n a p a r a l l e l connection with it, a 3-in. rupture disk with a bursting pressure of 15 p s i . In relieving a t the lower pressure the 3-ine-disk reduces the dynamic impact on the condensing system when t h e large disk ruptures. Calculated flows through the 3-in. d i s k indicates a negligible pressure increase downstream of the 10-in. disk, allowing it t o rupture as planned. 176 A b i n . hand valve w i t h an extension handle t o the operating f l o o r l e v e l i s piped i n p a r a l l e l with t h e two rupture disks t o permit equalization of the pressure on the disks when the c e l l s are being pressure t e s t e d above t h e normal operating pressure f o r the disks.

With the reactor c e l l a t 40 psig and the vapor

condensing system a t 30 psig, the estimated mass flow rate i n l i n e 980 i s 16 lb/sec. 163

Line 980 continues underground t o the vapor condensing

tank, VT-1, located east of the v e n t i l a t i o n system stack, see p l o t plan, Fig. 3.2.

A 12-in. expansion j o i n t i s provided i n l i n e 980 t o absorb

thermal expansions.

The vapor condensing tank, o r water tank, i s a v e r t i c a l tank about

two-thirds f u l l of water, through which gases forced from the reactor c e l l i n a major accident would be bubbled t o condense t h e steam.

The

tank contains about 1,200 f t3 of water stored a t 7O0F, o r less. I"ne es6 timated maximum of 5 x 10 Btu t h a t could be released from t h e f u e l salt i n the reactor and drain tank c e l l s would therefore r a i s e the water tempera t u r e t o about 1u0F. '@& , The non-condensible gases are vented t o a large gas storage tank. The v e r t i c a l water tank i s 10 f t OD x 23 f t 4 in. high, including the ASME flanged and dished, 1/2-in.-thick, s h e l l i s 3/8-in.

top and bottom heads.

The

thick and constructed of SA-300 Class I, A-201, Grade B

L.'

(d t;

firebox steel. 125

There are stiffening rings, 1-in. thick x 3 in,, lo-

cated on the exterior about 2 f t 6 in, apart. The tank i s designed f o r 8 psis at 100°F or 63 p s i s at 300OF. The =-in. gas i n l e t pipe i n the top head extends 13 ft 8 in, into the tank t o about 6 f t below the normal

j i j -?

water level, and terminates in a cylindrical screen, u-7/8-in. OD x 1 4 in. long, perforated with 7/32=in,-diam holes on 3/8-in. centers, and providing 315 free area. See ORNL drawing D-KK-B-41283. The gas i n l e t line in the interior of the task has a =-in. pipe cross about 3 f’t above the water level t o which are connected two =-in. cast-steel-body check valves. These check valves close when the gas flow i s into the tank but open t o return non-condensibles t o the reactor c e l l t h r o u a line 980 during c o o l d m a f t e r an accident. The tank i s f i l l e d t o the operating level w i t h potable water through a temporary line or hose. Uquid level indication i s provided by the f l o a t operated instrument, LI-VT-1. The pressure i s indicated by PI-VT-1, and the temperature i s measured. There i s no bottom drain on the tank, the water being removed by pumping should t h i s be required. The top head of the tank i s provided w i t h an 18-in.-diam blind flange t o serve as a manhole. The 12-in. discharge nozzle f o r non-condensible gases i s also in the top head. The tank is installed vertically w i t h the top about 8 f’t below the normal grade level of 850 f t and the bottom a t an elevation of about 819 ft. About 5 f t of additional earth i s mounded above the tank to provide biological shielding. The tank i s supported and also held down by a skirt on the bottom head bolted t o a reinforced concrete pad, 18-in. thick x 14 ft dim, which also includes a cylindrical w a l l , =-in. thick x 10 ft OD, and about 8 f’t high. The non-condensible gases leaving the top of the water tank through the =-in. pipet l i n e 981, flow through the expansion j o i n t in the line and t o a side nozzle on the gas retention tank, VT-2. Gases can accumulate in t h i s tank, i n i t i a l l y at atmoepheric pessure, until the pressure falls t o a lower level in the reactor c e l l . The gas then returns t o the reactor c e l l t o prevent the pressure from falling below 8.0 psis. Line 984, a 2-in. line with a hand valve (with removable handle) is provided t o vent gas t o the absolute f i l t e r s and ventilating system stack.

. 448 The gas retention tank i s 10 ft OD x 66 f t 3-1/2 in. long, including the two ASME 1/2-in.-thick flanged and dished heads. The s h e l l is 3/8-in. thick, reinforced with 1-in.-thick x 3 in. rings located about

4 f t 7 in. apart.

The tank i s fabricated of SA-300 Class I, SA-201 Grade B firebox s t e e l and i s designed for 8 psia a t 100°F and 63 psia at 300OF. It i s anchored into a sand and gravel base by four 1-in.-dim galvanized s t e e l t i e rods fastened t o expanding type earth anchors. The nozzle end of the tank is anchored t o a reinforced concrete saddle and pad, roughly 18 in. thick, 12 f t wide, and 6 f t long. The centerline i s about 14 f t from the centerline of the vapor condensing tank and the elevation at the bottom i s

842 f t . A 1-1/2-in. sched 40 drain pipe, line 982, at the bottom, drains i n t o the vapor condensing tank. See ORmL drawing D - K K - B - ~ E ~ ~ . The drain tank condensers, line 338, and the relief valve on the water line from the thermal shield and f'uel pump, l i n e 885, are both vented t o the vapor condensing system by joining line 982. (See Section 15.2.)

L1 c

b i

449

18. BIOLOGICAL SHIELDING The MSRE building areas are divided i n t o f i v e classifications: (I), those w i t h high radiation l e v e l s t h a t cannot be entered under any circumstances a f t e r t h e reactor has been operated a t power, such as the reactor and drain tank c e l l s ; (11), those t h a t can be entered a short time a f t e r the h e 1 s a l t i s drained from t h e primary circulating system, such as the radiator area; (111), those t h a t can be entered a t low reactor L

power levels, such as the special equipment room; ( I V ) ,

areas which are

habitable a t all times; (V), the maintenance control room, which i s the only habitable area on t h e s i t e when c e r t a i n large-scale maintenance

operations a r e being performed.

These c l a s s i f i c a t i o n s are described i n

more d e t a i l i n Section 4.1. The MSRE i s designed t o permit prolonged operation a t 10 Mw without -E

exposing personnel t o more than t h e permissible dose

of 100 mrem/week i n

areas which are entered routinely and have unlimited access. 167 However, it i s ORNL policy t o l i m i t a l l personnel exposures t o a minimum and it i s not anticipated t h a t MSRF: operators w i l l accumulate 100 mrem/week except i n unusual circumstances.

The areas which w i l l have unlimited access and

which, therefore, might be occupied continuously, w i l l be e s s e n t i a l l y a t normal background l e v e l f o r the Oak Ridge v i c i n i t y . "Hot spots," o r areas of high l o c a l a c t i v i t y , are generally located near the reactor or drain tank c e l l penetrations and are i n areas which have only limited access, such as t h e coolant c e l l .

The overall a c t i v i t y i n t h e coolant c e l l , however, does not exceed 100 m r / h r . The blower house i s a l s o a limited access area, with a radiation l e v e l of about 20 mr/hr

near t h e No. 4 blower.

Although t h e special equipment room i s c l a s s i f i e d

a limited access area, t h e radiation f i e l d does not exceed about 10 m r / h r . The south e l e c t r i c service area, another limited access portion of t h e building, has a generally higher radiation l e v e l of 200 mr/hr, w i t h sane "hot spots" near t h e penetrations.

All the above estimates of a c t i v i t y l e v e l s are based on operation of t h e reactor a t the 10-Mw power level. ,

I ?u

%ased on 40-hr work week and t h a t 1 roentgen equals 1 rem f o r gama radiation i n s o f t body tissue.

450 The i n t e n s i t y of t h e r a d i a t i o n i n t h e a u x i l i a r y c e l l s i s less dependent upon t h e r e a c t o r power l e v e l than upon t h e nature of t h e materials present i n t h e c e l l s .

These conditions change from time t o t i m e , but i n

general, a l l t h e c e l l s have limited access. When t h e r e a c t o r i s s u b c r i t i c a l , a l l areas except t h e reactor, d r a i n tank and f u e l processing c e l l s , may be entered a few minutes af'ter t h e reactor i s shut down. i

I n general, access can be on an unlimited b a s i s

except where "hot spots" may e x i s t . 168 For example, i f t h e coolant s a l t were drained from t h a t c i r c u l a t i n g system, two b i n . - d i a m holes would be l e f t through t h e r e a c t o r shielding, one of which rrlooks" d i r e c t l y a t t h e

f u e l pump bowl, and could cause a localized beam i n t h e coolant c e l l of several r/hr.

Entry t o such areas and work i n t h e areas w i l l be monitored

and a d d i t i o n a l shielding provided as required.

18.1 General Description This section provides only a summary description of t h e b i o l o g i c a l shielding.

The general construction of t h e c e l l s and other areas i s described i n more d e t a i l i n Section 4 of t h i s P a r t I of t h e design r e p o r t . The calculations necessary t o confirm t h e adequacy of t h e shielding a r e presented i n Section 13 o f t h e nuclear analysis portion o f t h e report, P a r t 111.168'

16"

The shielding needed f o r t h e f u e l handling and

processing system is covered i n P a r t VII. Shielding required during maintenance procedures i s described i n P a r t X . The r e a c t o r v e s s e l i s surrounded, except for a 2-f't-diam opening a t t h e top, by a 16-in.-thick iron and water thermal s h i e l d .

This i s located within t h e r e a c t o r c e l l containment vessel which, i n turn, s i t s within a s h i e l d tank t o provide a 3-f't-wide annular space which i s f i l l e d with magnetite sand and l i g h t water.

The s h i e l d tank i s surrounded by a

c y l i n d r i c a l monolithic concrete w a l l 21 i n . t h i c k .

A portion o f t h i s w a l l facing t h e south e l e c t r i c service area and another portion facing

t h e coolant area a r e l e f t out i n order t o make t h e penetrations accessible. Barytes concrete block walls a r e provided t o s h i e l d accessible areas adjacent t o t h e coolant c e l l .

The a d d i t i o n a l shielding i s not necessary

g,-

451 i n t h e e l e c t r i c service area i n that there i s a minimum of 2 ft of conc r e t e between it and any accessible area. The top of the reactor c e l l i s constructed of a 3-1/2-ft-thick

layer

of barytes concrete blocks covered w i t h 3-1/2-f%-thick blocks of ordinary concrete.

The j o i n t s between t h e upper and lower layer of blocks a r e

staggered.

High-density shielding blocks a r e temporarily stacked above

t h i s as required. The pipe penetrations through t h e reactor and drain tank c e l l walls pass through sleeves which a r e f i l l e d w i t h magnetite concrete grout o r magnetite sand and water. bend.

Where possible, these l i n e s have an o f f s e t

The penetration o f t h e 30-in-dim exhaust l i n e through t h e bottom

hemisphere of t h e containment vessel required special treatment because o f t h e s i z e of the opening.

A shadow shield of a 9-in. thickness of

s t e e l i s provided i n front of t h e opening inside t h e c e l l and a 12-in.thick w a l l of stacked block i s erected outside t h e c e l l a t t h e foot of the ramp t o t h e coolant c e l l . The top and sides of t h e coolant and coolant drain tank c e l l s provide a t least 24 i n . of concrete shielding as protection against a c t i v i t y induced i n t h e coolant s a l t while t h e reactor i s producing power.

The

large openings provided between t h e coolant c e l l and t h e blower house f o r t h e cooling a i r supply t o t h e radiator, however, make t o shield t h e blower house from t h i s induced a c t i v i t y .

it d i f f i c u l t

A 12-in. wall

of barytes blocks is stacked across t h e opening between the reactor c e l l

and t h e r a d i a t o r duct t o shield t h e blower house area from t h e coolant

salt l i n e s . The drain tank c e l l has a minimum thickness of 3 f’t concrete w a l l s facing accessible areas.

f o r t h e magnetite

The top of t h e c e l l consists of

a l a y e r o f 4-f’t-thick ordinary concrete blocks covered by a layer of 3-1/2-ft-thick

ordinary concrete blocks.

a r e staggered.

The pipe l i n e s penetrating t h e c e l l w a l l s have o f f s e t s ,

The j o i n t s between t h e blocks

t h e smaller ones being cast i n t o t h e w a l l s .

Shield plugs are provided

for t h e l a r g e r penetrations. The 1/2-in. off-gas l i n e *om

t h e reactor c e l l , l i n e 524, i s

shielded by 4 i n . of lead as it passes through t h e coolant drain tank

452 cell.

Barytes concrete blocks a r e stacked t o a thickness of 5 f’t above

t h e l i n e i n t h e vent house, and lT-in.-thick s t e e l p l a t e i s provided above t h e bine between t h e vent house and t h e charcoal beds. ’7’

The

charcoal beds a r e submerged i n water and t h e p i t i s covered with two 18-in.-thick by 1 0 - f t - d i m barytes concrete blocks.

Barytes blocks

w i l l be stacked on t h e cover i f a d d i t i o n a l shielding i s required. The w a l l s of t h e f i l t e r p i t f o r t h e containment v e n t i l a t i o n system a r e 12 i n . t h i c k and t h e roof plugs f o r t h e p i t a r e 18 i n . t h i c k . The thicknesses of t h e walls and tops o f t h e a u x i l i a r y c e l l s i s given i n Table 4 . 3 .

Additional shielding i s provided by stacked blocks

on t h e west s i d e of t h e f u e l processing and t h e decontamination c e l l s .

453

19. EIECTRICAL SERVICES The MSRe 'electrical services system furnishes power for process punzps, equipment heaters, instrumentation, nuclear control and safety circuits, and various auxiliary equipment. Power i s a l s o provided for the building cranes, repair shops, and general. building lighting, ventilation and air conditioning. installation makes use of the relatively extensive e l e c t r i The c a l f a c i l i t i e s t h a t were installed for the ARE and ART operations i n the Building 7503 area. as required.

This existing equipment was modified and supplemented,

The installed e l e c t r i c a l capacity of MSRE process equipment, excluding general building services, i s about 2,000 kw.

The normal operating

load i s approximately 1,100 kw. mer is supplied from the Tennessee Valley Authority distribution system through two parallel 13.8 k v feeder lines. In the event of failure of the normal power supply from the TVA system, batteries provide the 48-v DC parer for the reactor control and safety circuits and also 250-v DC power t o drive a 25-kw motor-generator s e t t o supply AC parer t o other instruments and controls, the sampler-enricher station, the control-rod drives, and the lubrication systems for the salt circulating pumps. These batteries serve u n t i l the emergency diesel-generator s e t s can be started and loaded, a procedure normally requiring a maximum of 5 to 10 minutes." In event none of the diesel units can be started, battery capacities are more than ample t o maintain control of the reactor and t o drain the f u e l salt t o the drain tanks without damage t o the system. The three emergency diesel-generator s e t s have a combined capacity of 900 kw AC. ! l M s emergency AC power can drive the 3-kw, M-v, DC motorgenerator set normally supplying the reactor control and safety circuits. During the emergency period, the lube o i l systems, control-rod drives,

Whe time available f o r starting the ernergency diesel-generator units without draining the reactor is limited by the t h a w time of the freeze valve on the reactor drain line'lO3 and by the pressure and temperature r i s e i n the reactor containment vessel. A period of about 10 min i s e s t i mated t o be available.

454 and other important AC equipment mentioned above, can continue t o receive parer f r o m the battery-driven 25-kw motor-generator s e t (for at l e a s t two hours), or they may take power directly from the diesel-driven generators. W i t h the three emergency diesels in operation the reactor can operate a t the heat-loss parer level indefinitely u n t i l normal electric parer can be restored.

19 1 General Description A simplified one-line diagram of the e l e c t r i c a l supply and dis-

tribution system for the MSRE i s shown in Fig. 19.1. Reference numbers on this diagram are keyed t o the descriptive material in the following sections. The MSRE i s supplied w i t h e l e c t r i c parer from the 1 5 4 - b Tennessee Valley Authority system through a substation located j u s t north of the X-10 area (see Fig. 3.4). Either of two 13.8-lrv transmission lines from the substation, ORNL circuit 234 o r 294, serve the Building 7503 area and are interconnected through interlocked motor operated switches at the M Sm s i t e so that c i r c u i t 299 can serve as an alternative t o c i r c u i t

234.

The normal supply i s through ORmL circuit 234. The feeders supply a bank of three 250-kva, 13.8-lnr t o 48O-v, transformers located on the east side of Building 7503 t o provide power f o r general building services. D e feeder power i s also connected t o a new 1,500-kva, 13.8-lnr t o 48O-v, transformer located on the west side of the

building t o serve the MSRE process equipment load. The process equipment distribution system i s shown schemtically in Fig. 19.2. (OFDTL drawing D-KK-C-kll52) The 1,500-kva substation feeds a WA* switchgear bus which supplies power through c i r c u i t breakers t o three generator* switchgear busses, two TVA motor-control centers, two 250-hp radiator blower motors, and t o the 200-hp motor for the 250-v DC motor-generator set.

The two TVA motor control centers supply power t o

*Throughout the e l e c t r i c a l service system reference l i t e r a t u r e and drawings, the normal source of electric power has been designated "TVA," as contrasted t o the emergency source, which has been called "generator."

I-

13.8 KV CKT 2 3 4 HFlR

SWITCH

229

129

1500 KVA 13.8 KV/480V

_ .-- .

TO BUILDING SERVICES TVA SWflM GEAR BUS

GENERATOR BUS # 3 SWITCH GEAR BUS 3

t4OOA

I-k 0A

REMOTE

AUTOTRANSFORMER SWITCH

2 5 0 V - D C DISTRIBUTION PANEL

Lq DC

250V

I20V240V

6 FOP-2

60A POWER PANEL

A AUX. PANEL

0 COP-2

SAMPLER a CONTROL ROD DRIVE

FIG. 19.1 SIMPLIFIED ONE-LINE DIAGRAM OF ELECTRICAL SUPPLY SYSTEM

-t

457 t h e l e s s c r i t i c a l process heater d i s t r i b u t i o n centers and t o a few non-

c r i t i c a l smaller motors. The three generator switchgear busses are normally fed f r o m t h e TVA system but each has i t s own diesel-driven, 300-kw generator* t o supply emergency power.

Generator No. 5 supplies one heater d i s t r i b u t i o n panel

and two motor control centers which provide power t o the heater distribution panels f o r the more c r i t i c a l process heaters.** and generator No.

3 1

Generator No. 3

4 switchgear busses furnish power d i r e c t l y , o r through

motor-control centers, t o a l l c r i t i c a l motorized equipment and t o some instrumentation.

Where reactor process equipment i s i n s t a l l e d i n dupli-

cate, each u n i t i s supplied from a d i f f e r e n t generator bus t o provide g r e a t e r r e l i a b i l i t y of emergency operation. The process d i s t r i b u t i o n system includes the aforementioned 48-v DC motor-generator s e t which supplies power t o the important reactor c o n t r o l and safety c i r c u i t s .

This direct-current system operates from a b a t t e r y

supply during a f a i l u r e of the normal power source u n t i l either diesel

No. 3 o r No.

4 can be s t a r t e d .

The building services d i s t r i b u t i o n system i s shown schematically i n

Fig. 19.3.

This system supplies power for building and grounds lighting,

for heating, v e n t i l a t i n g and air conditioning, and for maintenance services, such as cranes, welding, e t c . The power i s supplied from two main dist r i b u t i o n panels and from various l i g h t i n g panels located throughout the building.

Brt of the building lighting load can be transferred t o the

generator No. 3 switchgear bus f o r emergency l i g h t i n g i n event of f a i l u r e of the normal supply f r o m t h e TVA system.

*The No. 5 diesel-generator u n i t has a nameplate r a t i n g of 1,200 kw, b u t has a continuous duty output of 300 k s ~due t o the l i m i t e d output of the d i e s e l engine. See Section 19.3. **Across-the-line motor starter contactors and c i r c u i t breakers i n the motor control centers o r i g i n a l l y i n s t a l l e d for the ART are u t i l i z e d extensively i n various MSRiZ c i r c u i t s and are termed "motor control centers'' i n the MSRE l i t e r a t u r e and on drawings even though a p a r t i c u l a r center may be controlling a heater, f o r example, rather than a motor.

E s

> 3: :t h .

-4

_--

459

19.2

Transmission Lines and Substations

Electrical power is supplied t o the MSRF: s i t e by two 13.8-kv overhead feeder lines from the ORmL substation located j u s t north of the main

X-10 area, see Fig. 3.4. These are designated ORNL circuits 234 and 294. The preferred supply arrangement is through circuit 234, through the motorThe alternate arrangement is through c i r c u i t 294 and the motor-operated disconnect switch M-2. These two

operated disconnect switch, M-1.

switches are interlocked t o prevent both switches from being closed a t the sane time. The switch, M-1, has an opening delay timer which allows a 1 t o 10 sec loss of power on circuit 234 before the s w i t c h opens, then the switch M-2 automatically closes if there is supply voltage on c i r c u i t 294. The control c i r c u i t for M-2 w i l l also prevent the switch from closing i f there i s an e l e c t r i c a l f a u l t in the Building 7503 area. The control power for the breakers M - 1 and M-2 is from the Building 7503 area 250-v DC system. The switches can be closed from the remote pushbutton station in the MSRE auxiliary control room o r manually at the s w i t c h poles C and D located north

of the building. The process power substation is located west of Building 7503 and consists of an o i l filled, l,5OO-kva, 13.8-kv/480-v, 3-phase, &-cycle, 3-wire, delta-connected Uptgroff transformer with a maximum inrpedence of 5.75$. The 13.8 kv supply enters the substation through a high voltage, fused cutout disconnect switch.

The 480-v transformer output enters the switch

* (0.998-in. d i m ) cables l a i d i n underground

house through twelve 750 mcrn

conduit, through a 1,600-amp breaker, R, t o connect t o the TVA switchgear bus. The building service substation i s located t o the east of Building 7503 and is supplied through a disconnect switch. The substation consists

of three 250 kva, single-phase transfonners connected delta-delta t o reduce the 13.8-kv supply t o 118o-v, 3-phase, &-cycle power. The transformer output is brought into the building through nine 500 mcm (0,814-in. d i m ) underground cables. Six cables (two per phase) lead t o the 600-m~main

*mcm = thousand circular mils.

460

c i r c u i t breaker f o r d i s t r i b u t i o n panel No. 1 and the other three lead t o the 600-amp d i s t r i b u t i o n panel No. 2.

These c i r c u i t breakers a r e

located on the w a l l of the main building a t column D-4 (see Fig. 4.4)

at the 840-ft elevation.

19.3 Emergency Diesel-Generators O f the f i v e diesel-generator u n i t s i n i t i a l l y i n s t a l l e d i n the

generator house f o r the ART project, two were removed f o r other duty and three remain f o r use i n the WIG.

These units, numbered 3, 4 and 5,

have a continuous capacity of 300 kw each, as explained below. Individual busses were selected f o r d i s t r i b u t i o n of the power from

the generators t o the centers on the basis of calculations of the s i z e and nature of the MSRE emergency e l e c t r i c a l loads, the s i z e s of the e x i s t i n g switchgear, and the c h a r a c t e r i s t i c s of t h e diesel-generator

units.&

A ground detector alarm i s provided f o r each bus.

The three diesel-generator u n i t s can be operated from control panel6 located i n the switch house.

These panels have the necessary switches,

controls, and indicating meters t o adjust the generator output voltage and frequency and the synchronizing equipment f o r p a r a l l e l i n g generators

No. 3 and 4 with t h e TVA system.

A l l three u n i t s can be started remotely

from panels DPM 3, DPM 4, and DPM 5 i n the a u x i l i a r y control room.

These

panels a l s o include remote switches t o open c i r c u i t breakers A 1 and A2 t o i s o l a t e busses 3, 4, and 5 fromthe TVA system and t o close breakers A3, Ab, and A5 t o connect the generators t o t h e i r respective busses.

The remote panels a l s o include d i e s e l annunciator alarms, voltmeters

and ammeters f o r the generator outputs, and a voltmeter f o r the TVA system power.

19.3.1

Diesel-Generator Units No.

3 and No. 4

These identialmachines are Allis-Chalmers Buda units, Model 8DC SG-2505. 172

The engine i s r a t e d a t an available brake horsepower of

450 at 1,200 rpm. A 10%overload can be c a r r i e d f o r a maximum of four hours, which must be followed by a cooling period of at l e a s t two hours

at no more than the rated load.

The engines are started by a b a t t e r y

- 1

461 -

bank f o r each unit.

Annunciators are provided t o sound alamus on high cooling water temperature, high o i l temperature, low o i l pressure and

low f u e l level. The generator i s a direct connected Electric Machinery Model DCSCX-~OO-A~E, rated at 300 kw, 375 kva, 480 v at 0.8 power factor, f o r continuous service. Each generator frame i s equivalent t o a 500-kw, 625-k.~amachine, however, this oversizing having been provided t o compensate for the reactance load which would have been imposed by starting the large motor involved in the ART operations. Although the generator i s constructed t o AIEE and NEMA standards for an intermittent overload of 5 6 , the maximum overload i s limited t o lo$ by the capacity of the driving engines. (These overload values do not apply t o rapid load changes due t o motor stastings.) Synchronizing e q u i p n t enables diesel-generator unit No. 3 or No. 4 t o operate i n parallel w i t h the TVA power supply so t h a t the loads can be transferred from the generators back t o the TVA system without interrupting reactor operation. However, both units must not be operated in parallel w i t h the TVA system a t the same time. This would expose the motor control center busses t o the combined capacities of both generators and the WA system and would greatly exceed the current carrying capacity of the busses in event of a dead short in a connected load. 42 The individual busses f o r generators No. 3 and 4 supply a l l motors which need emergency power. Since the voltage drop i n a generator bus i s c r i t i c a l when starting motors, starting currents have been limited t o 540 amps" so t h a t the generator voltage . w i l l not fall below 80s of the i n i t i a l value.

19.3.2

Diesel-Generator Unit No. 5

The diesel engine f o r t h i s unit i s a Caterpillar Model D-397. It is rated at 455 bhp at f u l l load and at 1,200 rpm. It may be overloaded 15s f o r two hours, which must be folluwed by a cooling period of at l e a s t two hours at no mre than rated load.

bd ..

The engine i s started by a compressed air motor supplieB by a nearby air receiver and compressor. %e receiver stores sufficient air f o r five 10-sec'starts. The conrpressor *Equivalent t o a 75-hp motor with a starting current 5.5 times Full load rating.

462

can recharge the receiver i n 20 t o 30 min following one 10-sec start.

An annunciator sounds an alarm on high cooling water temperature, high

o i l temgerature, low o i l pressure, low f u e l level, and low s t a r t i n g air pressure. The generator was manufactured by Electrical Machinery, i s rated at 1,OOO kw, 1,250 ha, and i s direct connected t o operate at 1,200 rpm.

continuous loading it i s rated at 300 kw at 0.8 power factor.

For

As pre-

viously mentioned, the oversized generator was provided t o compensate for the reactance in starting large motors involved i n the ART.

Altho)lgh t h i s

generator was also b u i l t t o conform t o the AIEE and MEtvIA standards f o r intermittent loads of l5@, the maximum load i s limited t o 115% by the capacity of the driving engine. 19.4

19.4.1

Process Electrical Circuits

Switchgear Equipment

Except as otherwise indicated, the switchgear equipment i s located i n the switch house, as sham i n Fig. 19.4. The e q u i p e n t was manufactured by Westinghouse Electric Corporation. The busses are rated a t 1,600 anrps, 480 v, and have a 5O,OOO-amp short c i r c u i t carrying capacity.

The R, P, Q, and A4 c i r c u i t breakers are

Westinghouse Type DB 50, with a 1,600-amp frame, 50,000-amp asymmetrical, at 600-v, short c i r c u i t capacity.

* The remaining c i r c u i t breakers are

Westinghouse ryPe DB 25, with 600-amp frame, 25,000 anrp asymmetrical a t 600 V.

** See Table 19.1 f o r other data on switchgear busses and breakers.

19~4.1.1 TVA Switchgear Bus and Current--tin@;

Reactor.

%e TVA

switchgear bus, including breaker R i n the supply l i n e f r o m the substation,

i s located i n panels 2 through 5 on the south side of the switch house, as shown i n Fig. 19.4. There are ten c i r c u i t s connected t o the bus, as indicated i n Fig. 19.2.

The first two 300-amp breakers, P and Q, supply

power t o the 250-hp motors of the blowers which supply cooling air t o the

*60,000 amp asymmetrical at 480 V. **35,000 amp asymmetrical a t 480 v.

463

:-r

f 3

UNCLASSIFIED ORNL-DWG. 64-6747

MCC T-1

DC-AC-MG

1o:i /*/

MCC 6-3

65-2

MCC T-2

I l-4

Si I65

TVA

I I I I

1 5 0 0 KVA TRANSFORMER

MCC 64 METERS 8 CONTROL

I I

MCC 05-1 ~

G MAINS

IZING

FIG.19.4 LOCATION OF EQUIPMENT IN SWITCH HOUSE

464 Table 19.1.

Switchgear Bus and Breaker Data

Tap and Breaker

Termination

Size ( W S

Breaker Operation

dation

Cable, No.

and Size

Starter Location

Pot e n t ial "ransfomer

TVA Switchgear Bus

Current Transfomy

Instrument L oation Interlocking Action Voltmeter h e t e r Wattmeter

Remarks

TVA Bus

l600

Rec op sw.

3-5, Local

Supply frcgn substation.

MB-1

300

R e c op sw.

3-5, E R

Breaker-starter cabination

MB-3

300

R e c op sw.

9-59 MCR

sw3 Bus 3

600

Elec op sw.

3-3, Local

Close before A-1

B r e a k e r - s t e e r cambination. Voltage is TVA supply. In series with A-1.

swg Bus 4

600

Rec op sw

3-3, Local

Close before A-2

I n series with A-2.

swg 3-

600

Elec op sw

;-2, Local

Close if A - 4 is open.

MCC T-1

600

Manual

;-2

MCC T-2

600

Manual

2-2

MG-1

300

Manual

5-2

spare

Spare

PT o r main bus f o r X and Y wattmeters.

Under voltage t r i p .

;-3

i-3

Switchgear Bus No. 5 AA

MCC 5-2

350

Elec op su

i-1,

MCR

HDP G5-BB

225

Rec op su

i-1,

Local

MCC 5-1

350

Elec op sw

i-1,

MCR

A-4

From DG-5

600

Under voltage t r i p .

i-1

Ret op sw

;-XI., MCR

Close i f Z is open. Note:

Reverse current t r i p .

See Appendix for explanation of abbreviations.

~ . ~ . -....

.".... .

.__

465

'4'

radiator.

The remaining eight c i r c u i t s a r e connected t o the bus through

a current l u t i n g reactor. This inductance c o i l p r o t e c t s the busses and c i r c u i t breakers i n event of dead shorts i n the feeder c i r c u i t s by creating a back electromotive force t o limit the short c i r c u i t current. There are three Westinghouse Type MSP

Terminc

at 16.6 kva, single-phase, 1,200-ap, 13.8 voltage drop, and 480-v l i n e . Two of the eight c i r c u i t s supply the TVA motor control centers T-1 and T-2 through the c i r c u i t breakers X and Y. Three c i r c u i t s supply the generator switchgear busses through breakers S, T and 2. Another c i r c u i t provides power f o r the 250-v DC motor-generator s e t through breaker W. Circuits U

A-1

A-5

and V are spares.

19.4.1.2

Mcc =,

See ORNL drawing D-KK-C-41175.

Switchgear Bus No.

2. This bus i s located i n panels 8 and

9 on the south side of the switch house, as indicated in Fig. 19.4, and i s normally supplied w i t h power from breaker S on the TVA bus through breaker A 1 located a t panel 8. This bus has an a l t e r n a t e , emergency parer supply through c i r c u i t breaker A5, from the 300-kw diesel-generator set No. 3. Switchgear bus No. 3 supplies the following equipment: the coolant c i r -

culating pump (breaker K), the component cooling gas blower No. 1

(breaker H), the 100-kva emergency l i g h t i n g transformer (breaker M),

the

motor-control center G-3 (breaker L), and the spare c i r c u i t breakers G,

J and N.

19.2.

Data f o r t h e switchgear bus No. 3 c i r c u i t s a r e given i n Table

(ALSO, see ORNL drawing D-KK-C-41176.) 19.4.1.3 Switchgear Bus No. 4. Bus No. 4 is located i n panel 10 on

the south side of the switch house, see Fig. 19.4.

A-2

- 6~2207reactors, one f o r each phase, r a t e d

supplied w i t h power from the TVA system through breaker T and through

Bus

breaker A2 on the No.

A-3

BUS

mel

Ccp-

MCCd

The bus i s normally

4 bus.

The bus i s also provided with emergency

power through breaker A3, connecting it t o the diesel-generator set No. Switchgear bus No.

4 supplies power t o the f i e 1 c i r c u l a t i n g pump (breaker

D), component cooling gas blower No. 2 (breaker E), and the motor-control center G-4 (breaker F). (See ORNL &awing D-KK-C-41176.) 19.4.1.4 Switchgear Bus No. 5. The generator No. 5 switchgear bus i s located i n t h e f i r s t panel on the south side of the s w i t c h house and i s normally supplied with power from the TVA system through breaker Z. I-

This bus i s also supplied w i t h emergency power from the diesel-generator

unit No. 5 through breaker Ab.

The bus supplies parer t o the heater

i !

i j

i i

-n --

S B

, l I

I I

466

;ion

Interlocking Action

Remarks

Watt~x~rkei

Close only m e r S.

Can not close if E 16 ClOSed.

Reverse current trip. VAR OP DP S w l y i n series with S. Reverse current trip. VAR on mq SWPly frcan E-3. Under voltage trip.

Under voltage trip. Voltage for bus and Mesel annunciator

Close only m e r T

Reverrte current trip. susply l a serles with T. Reverse current trip. S w l y Avnn DIG-4. Under voltage trip.

Can not close i f H 1s closed.

Under voltage trip. Voltage is bus vel-e and Mesel-generator annunciator.

ations

467

d i s t r i b u t i m panel GS-BB (breaker BB), the motor-control center G 5 - l (breaker AA),

the motor-control center G5-2 (breaker CC), and a spare

. See ORNL drawing D-KK-C-41176.

c i r c u i t (breaker DD) 19.4.2

Motor-Control Centers

Motor-control center equipment w a s manufactured by the General E l e c t r i c Company.

The busses a r e 600-amp, 480 v, and have a short c i r c u i t

current capacity of 25,000 amp a s m e t r i c a l a t 480 v. a r e of 100-amp minimum frame size.

The c i r c u i t breakers

Data f o r the motor-control center equip-

ment a r e given i n Table 19.3. 19.4.2.1

Motor-control center T-1 i s lo-

TVA Motor Control Centers.

cated i n panels 1 and 2 a t the e a s t end of the switch house, as indicated i n Fig.

19.4. The bus i s supplied with power from the TVA system through

the switchgear breaker X. t r i b u t i o n centers, T1-A,

The bus supplies power t o three heater d i s T1-B, and T1-C.

Circuits T1-D, T1-E,

and T1-F

a r e spares. Motor-control center T-2 i s a l s o a t the e a s t end of the switch house i n panels 8 and 9.

Power i s supplied through t h e TVA breaker Y.

The bus

provides power t o two motor-control centers and three heater d i s t r i b u t i o n Three of these are spare c i r c u i t s .

centers, through c i r c u i t s T2-S and T2-2. 19.4.2.2

Generator No. 3 Motor-Control Center.

Motor-control center

G - 3 i s located on panels 3 through 7 i n the e a s t end of the switch house. This bus receives power from switchgear bus No. 3, as mentioned i n 19.4.1.2,

above.

The bus supplies power t o 24 c i r c u i t s i n the process system, as

l i s t e d i n Table 19.4.

It may be noted t h a t f i v e c i r c u i t s are omitted from

the t a b l e since they a r e spares. 19.4.2.3

Generator No

Motor-Control Center.

This motor-control

center i s located i n panels 2 through 10 on the north side of the switch house, as shown i n Fig. 19.4. switchgear bus No.

Provided with power through breaker F, f r o m

4 (see Section 19.4.1.3,

power t o 19 i t e m s of process equipment. formation i s given i n Table 19.5. provide a t o t a l of 34 c i r c u i t s . c

*See footnote, page 19.3

above), t h i s center supplies

The breaker data and r e l a t e d in-

Fifteen spare c i r c u i t s a r e included, t o

468

Table 19.3.

Tap and Breaker

Termination

FQuipment Connections t o TVA Motor Control Centers

Breaker Size (amps1

Starter Size Location

Cable No. and Size

Intervening Eqyipnent

Motor Control Center T-1 T1-A

Htr M s t r Tl-A

xx)

!IX-B

H t r M s t r Tl-B

xx)

T1-C

Etr Distr T1-B

200

Tl-D-F spare

3 No.k/O 3 No.k/O 3 No.k/O 3 No.k/O

3 N0.12

Motor Control Center T-2 “243

HCV 9754

P-V

PnlEHtrT2-Vl

100

“2-W

RiL E H t r T2-Wl

100

P-x !E?-Y

RcEl Htr E - Y

P-TU

Spare

T2-TZ

Spare

30 200

Note:

MB-3

75-k.W 480/120, 2404 xfhrr. 75-ha,

Console

3 N0.2

4w=% 3 N0.2

240-v xmfr.

3 N0.12 3 No.14

See Appendix f o r explanation of abbreviations.

469

Table 19.4.

Tap and

Termination

Breaker

I n s t r Pnl 3

Equipment Connections t o Motor Control Center G-3

Breaker Starter Size Size Location (amps)

Intervening Equipanent

30-kva w/m,

c-1

100

S w P mfJ

DCC

30 15

CCP

MG-2

RCC -1

FOP-1

TF-1

HW-9%

14 15 16 17

HW930B AC -1

30 15 15 15 15 15 15 100

48-v pnl

1 1

MB-2 MB

MB-2

IR IR 3

MB-3 MB-3

OnEquip.

100

Diesel Aux Pnl CCC -1 I n s t r Pnl

CTP

mnrswfrcan

3 N0.6 3 N0.2 3 N0.2 3 N0o.12

MCC 44-5

MB-2

Xfer Sw MCC-4

MB-2

243-2

2 2

MB -2

MB-4

SF-1

100

m-3

Note:

208-v Xfer Sw i n SH

Cable No.

and Size

7.5-kba 480/120, 240-v xmlr

MB-2

See Appendix for explanation of abbreviations.

3 N0.12 3 N0.12 3 N0.12 3 N0.12 3 N0.12 3 N0.12 3 N0.12 3 N0.6 3 N0.2 3 N0.12 3 No.12 3 N0.8 3 N0.8 3 No.10 3 No.&

470

Table 19.5.

Equipment Connections t o Motor Control Center G-4

Starter Size Location

Intervening Equipment

Cable, No. and Size

Xfer Sw in SR

3 N0.12 3 N0.12 3 Noel2 3 N0.12 3 N0.12

Tap and Breaker

Tednation

Breaker Size (smps)

G-4-2

c -1

100

5 9

DCC

MG-3

COP-1

TF-2

15 15 15 15

DR-1

2 N0.10

16 17

Am DP

ccc

30 15

OnEquip

CTP-2

MB -2

Twp-2

23 24 26

50 50

MB-4

DR-2

15 30 30

MB-2 On Equip MB -2

3 N0.2 3 N0.12 3 N0.8 3 N0.8

480/120,240-vxfmr I n s t r F'nl 1

31 32 33 34

RCC -2

AC -2

(2) 1

MB-2

1 1

48-vPnl

MB-2

Xfer Sw

3 N0.12 3 N0.10 2 N0.10 2 No.4

100 25 -kva, 480/120, 240-v, 1 # xfhr

AC -3

100 100

SF-2

100

3 3 3

MB-2 MB-2

MB-3

Note: See Appendix f o r explanation of abbreviations.

2 No.4 b

3 N0.6 3 N0.6 3 No.4

471 19.4.2.4

Generator No. 5 Motor-Control Center.

Motor-control

center G 5 - l i s i n s t a l l e d i n panels 1 and 2 on the north side of t h e switch house.

The parer supply i s from switchgear bus No.

The center provides

power through transformers t o the h e a t e r d i s t r i b u t i o n panels, which w i l l be discussed subsequently.

There are three spare c i r c u i t s .

The breakers and

other d a t a a r e l i s t e d i n Table 19.6, Motor-control center G5-2 i s connected t o three supply c i r c u i t s , two of which supply h e a t e r s and one which serves as a spare.

The center i s l o -

cated i n panel ll on t h e north side of the switch house.

Data on t h e

breakers i n t h i s center a r e a l s o given i n Table 19.6.

19.5 Building Service C i r c u i t s m e building service c i r c u i t s a r e shown schematically i n Fig. 19.3. The c i r c u i t s are supplied with power from the 750-kva substation through two d i s t r i b u t i o n panels.

These panels, No. 1 and No. 2, a r e located on

the w a l l near column D-4 a t the 840-ft elevation.

19.5.1

Building Service Panel No. 1

This d i s t r i b u t i o n panel i s supplied with 480-v three-phase power through a ~OO-ELI-IIP c i r c u i t breaker.

It provides power t o 11breakers

which supply power t o the equipment l i s t e d i n Table 19.7.

Data f o r

l i g h t i n g panels 1A and IAl, which a r e supplied from the transformer i n ,

c i r c u i t 9 of panel No. 1, are given i n Table 19.8.

'Ihe transformer i s

a K u h l m a n E l e c t r i c Company, Spec No. 114.09, 225-kva, 480/208~-120-~, 0

3-phase, 60-cycle, dry type, r a t e d a t 80 C temperature r i s e . 19.5.2

Building Service Panel No. 2

Three-phase power a t 480 v i s provided for t h i s panel through a

6OO-amp main breaker, as indicated i n Fig. 19.3. The panel i s r a t e d at 325 amps, and has 16 connections t o breakers or fused switches, which lead t o t h e equipment l i s t e d i n Table 19.9.

472

Table 19.6.

Tap and Breaker

G-5 -lA

Termination

Equipment Connections t o Motor Control Centers c-5-1 ma G-5-2

Breaker Size

Starter Size Location

Pnl D G-5-LA

112-ha 480/120, 3 N0.2 208-v Xfmr 112, 5-kva 480/ 3 No.2

200

pnl E G-5-1-1

200

120,208-v Xfmr

~512

Cable No. and Size

( m P s1

1 - 5 C

Intervening Equipment

Pnl n G-5-LD

75-kva, 480/120,

200

3 No.1

208-v Xfmr

1 - 4 Spares G -5 -2X

no3

100

Y B E F

G -5 -2Y -B2

200

spare

HCP

Spare Spare

spare

Note:

See Appendix f o r explanation of abbreviations.

2 N0.2

3 No.4

473

Table 19.7.

Circuit

Connections t o Building Service Panel No. 1 Breaker Cable, No. Fuse and Size

Equipment

Load hP

Remarks

13 6

Both cranes on same fuse and breaker.

( q s )

10-Ton Crane 3-Ton Crane Spare Fused Sw 852-ft RW

spare

Change House Vent Fan W-iPt El- H t r Fan

3 N0.12

852-ft Rev H t r Fan

3 Noel2

6 7

sp=e Two 3# Recept.

15 70

3 ~0.4

MCR Air Conditioner

225-kva XAnr

spare

70/70

3 N0.8

70 25

3 N0.8 3 N0.12

mo 3 0 - q fused sw. 1/2

3/4

Vent fan interlocked with circuit N0.5.

1-112

Note:

See Appendix f o r explanation of abbreviations.

474

Table 19.8.

Connections t o Lighting Distribution Panels IA and W I

arcuit

Lighting Panel

Panel Location

Lights Location

Cable, No and Size

Fused

Lighting Distribution Panel IA 0

MCR-1

852-ft ELw 0

MCR-2

400

MCR

100

4 N0.2

Yes

100/100

Yes

100

4 N0.2 4 N0.2

100

4 N0.2

100 100

4 N0.2 4 N0.2

Yes

90/100

4 N0.2

Yes

4 N0.2

100/100

4 N0.2

Yes

1 N0.2/0

Tm and East

TRM

SA1 N-5

8524% ELW in MCR

MCR

840-it KLw Lights Htr, 1st Floor Guard Portal

B D

8404% KLW

8524% ELW

D-3 Hall

852-ft ELw, E, 1, 2, 3, MCR mgh Bay Area Sump Vent

3 No.4/0

MCR

Below MCR

852-ft ELW

c -5

mgh Bay Lights Three Roof Vents

m-ft ELev M a t i n g Distribution Panel M l

1-6

spares

Store Rocan Diesel House

Store Rocan, Diesel 100/100 House, SH

4 N0.2

Service Roan

Service R o m

4 N0.2

Note:

100

See Appendix for explanation of abbreviations.

475

Table 19.9.

Connections t o Building Service Panel No. 2

Circuit

Ekpipnent

Two W-v, 3 # Recept Spare

3 4

Load

Remarks

3 N0.6

I n service area.

3 No.4

Service H, B1, €I HE3 A4

spare spare spare

6 7

spare

Spare

spare

spare Roll-up Doors

Breaker Cable, No. and Size Fuse

Two W - v , 3 # Recept

Spare

13 14

Two fans, One H t r

spare

30 (F) 3 N0.10

30 (F) 3 No.10

Tap- bottom lMt SW.

South FIigh Bay Area

spare

Note:

See Appendix for explanation of abbreviations.

476

19.6 Direct-Current E l e c t r i c a l Systems There a r e two independent d i r e c t current e l e c t r i c a l systems, an

existing 250-v system and a new 48-v system i n s t a l l e d f o r the MSm.

The

25-kw motor-generator s e t driven by the d i r e c t current system t o supply emergency power t o c e r t a i n important process equipment i s discussed i n t h i s section.

The location of the major components i n the two DC systems

i s sham on ORNL drawing D-E-C-55106.

19.6.1

B t t e r y , M-G Set and Distribution Panel f o r 250-v DC System

"he 250-v DC system provides emergency power t o various important

lighting and switching c i r c u i t s and drives the 2 5 - b DC-AC motor-generator set used t o supply l20/240-v AC power t o the control-rod drives, sampler-

enricher, etc.

19 6 1.1

The 25-kw DC-AC M-G s e t i s described i n Section 19.6.3. AC-DC, l25-kw, 250-v Motor-Generator Set MG-1. The 250-v

DC power source i s a Reliance E l e c t r i c and Engineering Company motorgenerator set, Model 1TH-11924.

It i s mounted i n a s i z e 6-FM sheet

s t e e l cabinet, with a pressure-ventilating system employing dust f i l t e r s . The M-G u n i t i s mounted on a fabricated steel base inside the cabinet.

The motor i s a 200-hp s q u i r r e l cage type, frame B-6085, D/564642, operating at 1,765 r p m on a 440-v, 60-cycle, 3-phase power supply.

It The motor has

i s rated a t 50°C temperature rise under continuous duty. b a l l bearings and an F-2 mounting with s p e c i a l double shaft extensions. The direct-connected generator has a capacity of 125 kw and supplies

power at 250 v DC. The generator frame i s No. 385-TY. The u n i t i s a shunt-wound type, with separate excitation at 230 v, and i s rated at 50°C temperature rise. tensions.

The ball-bearing-mounted s h a f t has s p e c i a l double ex-

An over-speed, normally-closed, switch i s mounted on the f r o n t

end. 19.6,1.2

Bttery.

The driving motor i s supplied with power through

breaker W at the TVA switchgear bus.

There i s a l s o a b a t t e r y f o r emergency

power, which consists of 120 B i d e cells, Type FOP, rated t o discharge

364 amp-hr as the voltage drops t o 210 v i n a 2-hr period. '73

A reverse-

current t r i p prevents a flow of current from the b a t t e r y t o the generator when the motor-generator set i s not operating.

4??

ed V

19.6.1,3

Distribution Pasel. The 250-17 DC distribution panel i s supplied through a w i t c h and a k K ) - a q f'use. The following circuits

are supplied by the panel through switches and fuses of the size indicated: DC emergency lights (3O-amp fclse), switchgear t r i p c i r c u i t (6O-amp f'use), TVA p e r transfer switch ( 3 O - m ~fuse), and the 25-kw M-G s e t ( b 0 - a ~ ~ fuse) 19.6.2

Battery, M-G Set and Control Panel f o r 48-v DC System

The 48-v DC system provides power f o r the electrical- and air-operated controls systems,

These systems normally receive DC power through e i t h e r

the 3-kw No. 2 AC-DC motor-generator s e t (driven by AC power taken from

the motor-control center G3-9 which i s supplied either w i t h power from the TVA o r diesel-generator unit No. 3), o r through the 3-kw AC-DC motor-

generator s e t No. 3 (supplied w i t h power either from the TVA o r from dieselgenerator u n i t No, 4).

In au emergency, when no AC power is available t o run the 3-kw motor-generators, 48-v DC power can be supplied directly from a 24-cell battery system described below. (See ORNL drawing D-KK-C-55112.) 19.6.2.1 AC-DC, 3-kw, Motor-Generator Sets. Each of the two identic a l units is an Electric Products Compmy diverter-pole, motor-generator ryPe h796u. 174 The 440-v, 3-phase, 6O-cycle, AC motor is rated at 5 hp at 1,750 rpm. It draws a maximum of 6.6 a q s and i s rated a t b 0 C temperature r i s e under continuous duty. The direct-connected DC generator is rated at 3 kw (53.5 a m p at 56 v). 19.6.2,2 Battery for 48-v System. The 24-cell battery supplying the 48-v emergency power u t i l i z e s Exide '!l?ytex'' FOP-19 cells. '73 me

cells have a 12-hr discharge capacity at 600 amp-hr when discharged t o k volts. The 24 c e l l s normally provide a potential of about 48 volts. 19.6.2.3 Control Panel f o r 48-v System. The control panel for the 48-v system'is located outside the battery room at the 840-ft elevation. The panel provides the controls t o start and stop the M-G sets, nm then 'Individually o r in parallel, t o detect system grounds, and t o recharge the battery. (See O m drawing ID-KK-C-55108 and drawing D-KK-C-55109. )

19~6.3 DC-AC 25-kw Motor-Generator Set MG-4 and Connected mad %%is motor-generator set is driven by the 250-v DC system and is used t o generate AC parer t o drive certain important process equipment in

478 in an emergency. The set is a Reliance Electric Model 1TH-11946,175 mounted in a size 5-FM sheet steel cabinet having a pressure ventilating system utilizing dust filters. The motor is a special direct current motor, frame No. 92-T. It is a shunt-wound type with 1.61-f~m, maximum field current. For operation at 1,800 r p m the field controller resistance at 258-v full-load voltage is 36 ohms; for 210-v full-load voltage the required resistance is 40 ohms. The motor is rated at a 40°C temperature rise for continuous service. The ball-bearing-mounted shaft has an F-2 mounting with back end extension. The generator is an Electric Machinery, fraIfE s-20, rated at 25 kw at 0.8 power factor. It is a single-phase, ~0/240-v, 3-wire unit, with field rheostat, field discharge resistor, and integrally mounted exciter. The generator supplies AC parer to the following equipment: instrument panel No. 3 (see Part 111); process power panel No. 3, which powers the sampler-enricher and control-rod drive motors; process power panel No. 2, which supplies parer to the fie1 and coolant salt lubricating oil pumps through two 220-v single-phase/kkO-v three-phase converters manufactured by the System Analyzer Corporation, Type 35; and the control p e r for diesel-generator unit No 5 (See ORNL drawing D-KK-C-41152.) To decrease the load on the 25-kw generator when running the motor on power from the 250-v battery system, the fuel and coolant salt lubricating pumps, FOP-2 and CoP-2, can be stopped and the two spare pumps, FOP-1 and CoP-1, can be started, these being driven by diesel-generator units No. 3 and No. 4. The instrument parer panel No. 2 and the process power panel No. 2 receive l20/24O-v AC power either f r o m the 25-kw motor-generator set or through the 480-v/~0 240-v single-phase instrument power trmsformer No. 1. This transformer takes its 480-v primary input via the motorcontrol center bus No. 4 and the TVA system, or in an emergency, from diesel-generator unit No. 4. The secondary of the transformer w i l l be connected to the instrument and process power panels through an automatic transfer switch which, on low voltage f r o m the 25-kw generator, transfers the load from the set to the motor-control center bus No. 4. This automatic switch will not transfer if there is no voltage on the No. 4 bus. (See O R m drawing D-KK-C-41152.)

L i 5

479

19.7 Heater Control C i r c u i t s Power i s normally supplied t o t h e process system heaters from t h e TVA system.

I n an emergency part of t h e heaters can be provided w i t h

power from diesel-generator s e t No. 5.

The power i s d i s t r i b u t e d through

eleven c i r c u i t breaker p3rd.s t o twelve heater control panels and t o one motor control center connection.

voltage) t o t h e heaters Power (i.g.,

i s manually regulated by variable autotransformers.

There a r e 136

heater control c i r c u i t s i n t h e process heating system, including 1 5 4

spare c i r c u i t s . The heaters on t h e process equipment and piping a r e described

i n t h e sections pertaining t o t h e p a r t i c u l a r pieces of equipment on which they a r e employed.

19.7.1 C i r c u i t Breaker Panels G5-LA, G5-lC, G5-lD, T2-V and T2-W These 120-208-v c i r c u i t breaker panels are located along t h e e a s t w a l l of t h e north-south hallway a t t h e 840-ft elevation.

Panels

G5-LA and G5-lC a r e supplied with power from112.5-kva transformers, Panels G5-U),

described below.

T2-V and T2-W receive power from

75-kva transformers. The c i r c u i t breakers supply power t o f i f t y s i x 2.8-kva Powerstats and t h i r t y - n i n e 7.5-kva Type 1256 Powerstats, a l l located on t h e heater control panels t o be discussed subsequently.

19.7.1.1 Transformers G5-LA and G 5 - l C , ll2.5-kva.

These two

transformers a r e located on t h e western side of the main building near t h e switch house.

480/208Y-12O-v,

They are General E l e c t r i c Company Model yT23Y3005,

3-phase, 60-cycle, indoor, dry type transformers r a t e d

a t 112.5 h a with delta-connected primaries and wye-connected secondaries. The temperature r i s e i s 80°c under continuous duty a t rated load. 19.7.1.2

Transformers G5-U),

T2-V and T2-W, 75-kva.

The G5-U)

transformer i s located on t h e western s i d e of t h e main building a t the 840-ft l e v e l , adjacent t o the G5-lA 112.5-kva transformer.

The

T2-V u n i t i s located a t t h e 840-ft elevation on t h e east s i d e of t h e north-south hallway and t h e T2-W transformer i s on t h e w e s t s i d e . A l l u n i t s a r e General E l e c t r i c Models gT23Y3004,

60-cycle, 480-v/120,208-v, rise.

75-kva, 3-phase,

transformers, rated a t an 80°c temperature

480

19.7.1.3 C i r c u i t Breakers. The breakers used on a l l f i v e of t h e

Ld e

above panels a r e Trumbull E l e c t r i c Company, Type TQL o r R, 100-amp, 120/208-~, three-phase, rated a t 4 w a t t s . 19.7.2

C i r c u i t Breaker Panels G5-BB, T1-A, Tl-B, T1-C, T2Y and G5-2Y.

These 480-v c i r c u i t breaker panels are located on t h e south s i d e of the east-west hallway a t t h e 840-ft l e v e l .

Panels G5-BB and G5-2Y

receive power from t h e N o . 5 diesel-generator bus; T1-A, T1-B and T1-C a r e powered f r o m t h e TVA motor control center, T-1; and panel T2-Y i s supplied f r o m t h e TVA motor control center T42. The c i r c u i t breakers supply power t o t h i r t y - e i g h t 30-kva induction regulators, which a r e controlled from the heater control panels described below. The breakers used i n a l l s i x c i r c u i t s a r e General E l e c t r i c Type CCB, 225-amp, ~OO-V, 3 - w a t t switches, with General E l e c t r i c Controllers

Type CR 2 8 1 1 ~ - 1 0 1 ~having , a 25-hp capacity with 3-phase, 440-600-v power.

19.7.3 C i r c u i t Breaker Panel G5-2X and Drain Line l o 3 Heater C i r c u i t . C i r c u i t breaker panel G5-2X takes power from t h e switchgear bus No. 5 t o supply a saturable reactor and a high-current transformer t o provide s t e p l e s s control of t h e current t o the resistance-heated drain l i n e 103.

19.7.3.1 Saturable Reactor. The saturable reactor i s a HeviDuty E l e c t r i c Company, Catalog No. D-73331, single-phase, &-cycle, u n i t , rated a t 25 kva, 460 l i n e v o l t s , a load voltage of 414 a t 60.5 amps, and with a DC control input of 4 t o 75 v. The t o t a l resistance i s about 54 ohms. The reactor i s located i n t h e north e l e c t r i c service a r e a between columns 5-B and 5-C a t t h e 824-ft elevation. The 4 t o 75-v DC control current t o t h e saturable reactor i s

h '

provided by germanium diode r e c t i f i e r s mounted i n t h e cabinet of heater control panel No. 8.

The DC output of t h e r e c t i f i e r s i s varied by

controlling t h e AC input through a Type 136 Powerstat mounted on t h e control panel.

(The Powerstat i s described i n Section 19.7.4, below).

A current transformer and ammeter on the control panel provide i n d i f

cation of t h e heat input t o t h e drain l i n e .

hd m

481

19.7.3.2

Special 25-kva High-Current Transformer.

The output of

t h e s a t u r a b l e r e a c t o r i s fed t o a s p e c i a l 25-kva transformer l o c a t e d i n t h e d r a i n tank c e l l .

The transformer w a s manufactured i n accordance

with ORNL Dwg B-MM-A-56244 by t h e Hevi-Duty E l e c t r i c Company. mary i s r a t e d a t 420 v and t h e secondary a t 18 v.

The p r i -

The u n i t supplies t h e

heavy current of up t o about 1,400 amps needed f o r r e s i s t a n c e heating of t h e INOR-81-1/2-in.

sched 40 d r a i n l i n e 103. The ungrounded s i d e

of t h e transformer i s e l e c t r i c a l l y connected t o t h e d r a i n l i n e about midway between t h e r e a c t o r and t h e d r a i n tank and t h e ends of t h e d r a i n l i n e have ground wires t o t h e grounded s i d e of t h e transformer.

19.7.4 Heater Control Panels and Equipment 0

The twelve h e a t e r control panels are located i n t h e north-south hallway at t h e 840-ft l e v e l , with panels 1 through 7A on t h e west s i d e of t h e hallway f a c i n g panels 8 through 11. Two a d d i t i o n a l h e a t e r panels a r e i n t h e same general l o c a t i o n t o c o n t r o l t h e heaters i n t h e f u e l processing system.

These are described i n P a r t VII.

A l i s t of t h e heaters controlled by each panel and t h e c o n t r o l s showing on t h e f a c e of t h e panel i s given i n Table 19.10.

The h e a t e r panels a r e supplied with power from t h e c i r c u i t breaker panels described i n Sections 19.7.1 and 19.7.2, above. " ;

Some of t h e s e

breaker panels supply as many as f i v e d i f f e r e n t heating panels.

crl

There are no heaters i n t h e process system having t h e power input automatically adjusted by heat-sensing devices and controls systems.

The

power i s regulated by manual adjustment of t h e voltage a t t h e h e a t e r cont r o l panel i n response t o temperature i n d i c a t i o n s i n t h e nearby temperature-scanning instrumentation, see P a r t 111.

19.7.4.1 Type 136 "Powerstat . I 1

This panel-mounted,

hand-positioned

v a r i a b l e autotransformer i s a product of t h e Superior E l e c t r i c Company and i s r a t e d a t 2.8 kva, 20 amps, 120 v, 60-cycle, with 0 t o 120-v output.

A schematic wiring diagram i s shown i n Figure 19.5.

t o t a l of

67 of t h i s type of c o n t r o l .

There are a

482 Unclassified O W DWG 64-8849

T2a-1

To Heater)

m-14 3

Figure 19.5.

Typical Schematic W i r i n g Diagram for r y ~ e12% Powerstat.

To Heater

> c

Typical Heater Connection x-

FV204-1-Fl c5-1-~1-2

12oV

FV204-1-CI.

Control Relay

5 To Freeze Valve FV2O4-1

FV2O4-1-FE

4 Mgure 19.5.

Typical Connection to Freeze Valve

Typical Schematic Diagram for Type 136 Powerstat.

483

Table 19.10 Heater Control Panels*

Heater Location HCP-1

Coolant System:

Heater

Radiator

CR 1

On-off and RaiseLower Push Buttons and 50/5-amp ammeter

CR 2

D i t t o , but 40/5 amp

CR 3 CR 4

D i t t o , b u t 40/5 amp

CR 5 CR 6

Ditto, but 50/5 amp

CR 7 CR 8

D i t t o but 40 amp

?I I? 11 ?I

Loop piping 11

D i t t o , b u t 50/5 amp D i t t o , but 50/5 amp D i t t o but 40 amp

H200-13

D i t t o but 40/5 amp

H201-12

D i t t o , but 40/5 amp

H202-2

D i t t o but 40/5 amp

Spare

No. 16 No. 1 No. 2

Radiator

CR 1

Spare Spare

HCP-2

Control on P a n e l H

D i t t o , but 1 5 amp D i t t o , b u t 40 amp D i t t o , but 40 amp

Coolant System:

Loop Piping Sleeves

Piping I n s i d e Radiator

0-300-v Ground Detection Voltmeter and 3 Line S e l e c t o r Buttons

CH 4

CR 5

CR 6

H200-14

Powerstat Type 1256 and l 5 - m ~ ammeter

H200-15

D i t t o , but 30 amp

H201-10

Ditto, but 30 amp

H201-11

Ditto, but 20 amp

H201-13

D i t t o , b u t 20 amp

* See panel layout ORNL Dwg E-MM-Z-51624.

Panels 1 through 7A are i n

west group, panels 8 through 11 are i n east group.

** Controls a r e l i s t e d as appearing on panel, reading l e f t t o r i g h t , t o p bd T

t o bottom.

484

HCP-3

Coolank System:

Heater Location

Heater

Control on Panel

Loop Piping

H202-1

Powerstat Type 136 and 15 amp ammeter

Loop Piping

H204-2

Loop Piping

~205-1

Freeze Valve Pot FV204-3

b I

Flow Transmitter:

HCP-4

Body t o p

FT20lA -1

Body t o p

FT20lA- 3

Body bottam

FT20lA-2

Body bottom

FT2OlA-4

Body t o p

FT201B-1

Body t o p

FT201B- 3

Body bottom

FT201B-2

Body bottom

FT201B-4

F i l l Line

~203-2

Spare

No. 5

Level Element Pipe

LE-CP-1

Level Element Pot

LE-CP-2

Freeze Valve

FV204-1

Adjacent t o FV

FV204-2

Freeze Valve

~~206-1

Coolant System:

~~206-2

F i l l Line

H204-1

F i l l Line

~206-1

Drain Tank Bottom

CDT 1

F i l l Line

H203-1

CDT 2

Drain Tank Upper CDT 3 Coolant Pump-Bottom CP 1 Coolant Pump

- Side Cp 2

Adj Freeze Valve

Drain Tank - Lower

Powerstat Type 136 and 20 amp ammeter

Raise-Lower Buttons and 30 amp ammeter

Powerstat Type 1256 and 30-amp ammeter ?I ??

n t-

b 7.

HCP-5

Heater Location

Heater

Control on Panel

Coolant Piping

H200-1

Powerstat Type 1256 and 20 amp ammeter

Reactor Cell:

Adjacent Flange 200 H200-11

Adjacent Flange 200 H200-12

Adjacent Flange 201 H201-1

Adjacent Flange 201 H201-2

~201-9

D i t t o , but 30 amp

Adjacent Flange 100 H100-1

D i t t o , but 30 amp

Coolant Piping

HCP-6

Reactor C e l l :

Coolant Piping Control RCH-1

H200-2

H206-3 H200-4A H200 4B

Coolant Piping Control RCH-2 Coolant Piping Control RCH-3

Coolant Piping Reactor

D i t t o , but 30 amp

~200-6 ~200-7 ~200-8

w 4

D i t t o , but 40 amp

~200-g~ ~200-9~ D i t t o , b u t 40 amp H201-4A H201-4B R 1

0-150-v Ground Detection Voltmeter and 3 Line S e l e c t o r Buttons

Reactor

R 3

Adjacent Flange 100 HlOO-2

On-Off and RaiseLower Buttons and 3 40-amp ammeters

Powerstat Type 1256 and 20 amp ammeter

Adjacent Flange 101 HlO1-2

Adjacent Flange 101 HlOl-3

486

HCP-7

Heater Location

Heater

Control on Panel

Coolant Piping Control RCH-5

H200-10 ~201-3

On-OFF and RaiseLower Buttons and 3 30 amp ammeters

Coolant Piping Control RCH-6

~201-5 ~201-6 ~201-7

D i t t o , but 40 amp

Fuel Piping Control RCH-7

mol-1

Ditto, but 30 amp

Fuel Piping

H102-2

Ditto, but 30 amp

Reactor Furnace

R 1

Ditto, but 40/5 amp

Reactor Furnace

D i t t o , but 40/5 amp

Reactor Furnace

R 3

D i t t o , but 40/5 amp

Heat Exchanger

HX1

Ditto, but 40 amp

Heat Exchanger

D i t t o , but 40 amp

Heat Exchanger

D i t t o , but 40 amp

Reactor Cell:

~102-3

- Lower

FP 1

Ditto, but 40/5 amp

Fuel Pump - Upper

FP 2

Ditto, but 40/5 amp

Fuel mUnp Spare

D i t t o , but 40 amp

Spare

Ditto, but 40 amp

HCP-7A Reactor Cell:

Reactor Access Nozzle

RAN-1

Reactor Access Nozzle

Ran-2

Powerstat Type 136 and 20 amp ammeter 11

Spare

Fuel Piping

H102-1

Powerstat Type 1256 and 30 amp ammeter

Adjacent Flange 102 H102-4

Ditto, but 20 amp

Adjacent Flange 102 HlO2-5

Ditto, but 30 amp

cri c

Heater

Control on Panel

H 103

Powerstat Type 136*, 2 on-off push-button s t a t i o n s and 50/5 amp ammeter

Freeze Valve

FV 103

Powerstat Type 136 and 20 amp m e t e r

Adjacent Furnace FFT Spare

H104-1

No. 7

Spare

No. 8

Drain Tank-Lower

FFT-1

Drain Tank-Upper

FFT-2

Drain Tank-Lower

FD1-1

Drain Tank-Upper

FD1-2

Drain Tank-Lower

FD2-1

Drain Tank-Upper

FD2-2

Heater Location

HCP-8 Drain Tank Cell: Reactor F i l l Line

i '

HCP-9

On-Off and RaiseLower Push Buttons and t h r e e 40/5 amp m e t e r s

Drain Tank C e l l : Powerstat Type 136 and 20 amp ammeter

Freeze Valve

FV104-1

Freeze Valve Pot

FV104-3

FFT F i l l Line

m04-5

FFT F i l l Line

H104-6

Freeze Valve

~~105-1

Freeze Valve Pot

FV105-3

Adjacent Furnace FD2 HlO5-l

FD-2 F i l l Line

H105-4

Freeze Valve

~~106-1

Freeze Valve Pot

FV106-3

Adjacent Furnace FD1 mo6-1

FD-1 F i l l Line

mO6-4

Spare

No. 9

Spare

No. 10

* This Powerstat controls t h e DC current f o r t h e saturable r e a c t o r wired i n t h e primary of t h e transformer f o r t h e resistance-heated l i n e .

488 Heater Location

Heater

Control on Panel

HCP-10 Drain Tank C e l l : Adjacent Freeze Valve FV104-23c

Raise-Lower Button and 20 amp ammeter

FFT F i l l Line

H104-2

Ditto, but 30 amp

FFT F i l l Line

HI.04-3

D i t t o , but 30 amp

FFT F i l l Line

H104-4

Ditto, but 30 amp

Adjacent Freeze Valve FVlO5-2*

D i t t o , but 20 amp

FD-2 F i l l Line

~105-2

D i t t o , but 30 amp

FD-2 F i l l Line

H105-3

D i t t o , but 30 amp

FD-2 F i l l Line

H104-7

D i t t o , but 30 amp

Adjacent Freeze Valve ~ ~ 1 0 6 - wD i t t o , but 20 amp FD-1 F i l l Line

~106-2

Ditto, but 30 amp

FD-1 F i l l Line

~106-3

Ditto, but 30 amp

Transfer Line

H110-2

Ditto, but 30 amp

Transfer Line

H110-3

D i t t o , but 30 amp

Spare

No. 1 2

Ditto, but 30 amp

Spare

NO.

D i t t o , but 30 amp

Spare

13 No. 14

Adjacent Furnace FFT

HlO7-l

Powerstat Type 136 and 10 amp ammeter

Transfer Line

~107-2

D i t t o , but 10 amp

Adjacent Flange

mO7-3

Ditto, but 20 amp

Freeze Valve

FVlO7-l

Ditto, but 20 amp

Adjacent Freeze Valve FVlO7-P

Ditto, but 20 amp

Freeze Valve Pots

Ditto, but 20 amp

FV107-3

D i t t o , but 30 amp

* These c i r c u i t s were l e f t i n place although due t o design changes t h e heaters have been eliminated.

489

trr’ R

Heater Location

Heater

Control on Panel

HCP-11 Drain Tank Cell:

Adjacent Furnace FD-2 ~ 1 0 8 - 1

Powerstat Type 136 and 10 amp ammeter

Transfer Line FD-2

~108-2

Ditto, but 10 amp

Adjacent Flange

~108-3

Ditto, but 20 amp

Freeze Valve

~n08-1

Ditto, but 20 amp

Adjacent Freeze Valve ~n08-23t- Ditto, but 20 amp I

Freeze Valve Pots

~ n 0 83-

Ditto, but 20 amp

Adjacent Furnace FD-1 HlOg-1

Ditto, but 10 amp

Transfer Line FD-1

HlO9-2

Ditto, but 10 amp

Adjacent Flange

H109-3

Ditto, but 20 amp

Freeze Valve

Fnog-1

Ditto, but 20 amp

Adjacent Freeze Valve FVlO9-2*

Ditto, but 20 amp

Freeze Valve Pots

FW-09-3

Ditto, but 20 amp

Transfer Line

H110-1

Ditto, but 10 amp

Spare

No. 1 5

Ditto, but 20 amp

* These c i r c u i t s were l e f t i n place although due t o design changes t h e heaters have been eliminated.

490

19.7.4.2

Type 1256 "Powerstat".

This Superior E l e c t r i c Company

variable autotransformer i s panel-mounted and hand-positioned and similar t o t h e Type 136 but i s rated a t 7.8 kva, 28 amps, with 240 v input and 0 t o 280-v output.

A t y p i c a l schematic wiring diagram i s shown i n

Figure 19.6.

Twenty-two of these "Powerstats" a r e used.

19.7.4.3

Motor-Operated Type 1256-1035 "Powerstat".

T h i s variable

autotransformer i s motor-operated and mounted on a rack on t h e west s i d e of t h e north-south hallway between columns C-2 and C - 3 a t t h e 840-ft elevation.

It i s controlled by a "raise-lower" push button on t h e

heater control panel.

The u n i t i s manufactured by t h e Superior E l e c t r i c

Company and i s rated a t 7.8 kva, 28 amps, 240 v input and 0 t o 280-v output, single-phase.

The motor i s operated on 115 v, 0.4 amps, and

has a 45 sec t r a v e l time.

A t y p i c a l wiring diagram i s shown i n Figure 19 6 .

Twenty of t h e controls are of t h i s type.

19.7.4.4

Induction Regulator.

Thirty-eight induction-type voltage They a r e

regulators were e x i s t i n g i n Bldg 7503 as p a r t of t h e ART.

located on t h e west side of t h e north-south hallway a t t h e 840-ft l e v e l , and below t h i s elevation on the south s i d e of t h e east-west hallway. Each regulator i s a General E l e c t r i c Company Type AIRT C a t No. 3263366, and a r e rated a t 480 v, three-phase, 36.5 amp, and 30-kva.

Each i s

positioned by "raise-lower" buttons on t h e heater control panels.

Since

t h e regulators can not produce zero voltage, "on-off" buttons a r e provided on t h e heater control panels.

A l i s t i n g of t h i s "on-off" button

f o r a heater tabulated i n Table 19.10 i d e n t i f i e s use of an induction regul a t o r , w i t h t h e one exception of t h e drain l i n e heater.

The regulators

have mechanical stops t o l i m i t the voltage output t o 208 v.

schematic wiring diagram for t h e induction regulator and a motor operator a r e shown i n Figure 19.7. There a r e 38 of t h e induction regulators i n use.

Nine feed 30-kva

three-phase transformers which supply heater breaker panels.

Eleven of

t h e regulators supply 10-kva single-phase transformers, one transformer f o r each phase.

The transformers a r e described below.

The remaining

regulators feed power d i r e c t l y t o the heater breaker panels.

The

number of heaters supplied by a regulator depends upon the s i z e and application of the p a r t i c u l a r heaters.

Unc lassified ORNL DWG 64-8850 120-v

See l3.gure 19.5 f o r Wiring

magram of Type 1256 Powerstat

'P D3-3H

i I

H204-1-T2

I I I I

Push Buttons on Control Panel HCP

Figure 19.6.

Powerstat Drive Motor

Typical Schematic Wiring D i a g r a m f o r Motor-Operated Type 1256-1035 Powerstat

Unclassified ORIGDWG64-8851

,-I3-I3

G5-l-D3-1

G!j-BB-3

5A 't

--a-----

Off I O-TO

-1 I,

1s I I TT.1 11

Pushbuttons on Control Panel.Bl;rP

Induction Regulator Crib

See Figure 19.6 for schematic wiring diagram of motor operator.

Figure 19.7.

Motor-Operated Induction Regulator

Contactor CRI.

493

19.7.4.5

Three-phase 30-kva Transformer.

There a r e nine of

these transformers located on a platform behind the heater breaker panels i n t h e east-west hallway a t the 840-ft l e v e l .

Each i s a

Jefferson E l e c t r i c Company, C a t No. 223-194, "Powerformer", rated a t 3 0 - k ~ a , three-phase, 60-cycle 480 4208-120 v, 36.1 amp and f o r 150°C temperature r i s e .

The transformer secondaries a r e provided w i t h groundSee ORNL

detection voltmeters mounted on the heater control panel. DWg D-KK-C-55137.

19.7.4.6

Single-phase 10-kva Transformers.

Thirty-three of these

transformers a r e mounted on t h e w a l l of t h e south side of the platform mentioned above.

Each i s a Jefferson E l e c t r i c Company, single-phase,

dry-type transformer, C a t No. 243-466, rated a t 10-kva, 240-480-v primary and 120-240-v secondary a t a 150°C temperature r i s e .

The

primaries a r e delta-connected and t h e secondaries a r e wye-connected and grounded.

19.7.4.7

See ORNL Dwg D-KK-C-55137. Heater Breaker Panels.

As s t a t e d above, an induction

regulator may supply several d i f f e r e n t heater c i r c u i t s .

I n such cases,

each heater c i r c u i t i s provided w i t h a c i r c u i t breaker.

Since most

of t h e breakers and panels a r e e x i s t i n g equipment a b p t e d f o r the E R E , there i s a v a r i e t y of combinations of makes and s t y l e s . Seven panels of c i r c u i t breakers are mounted on t h e e a s t w a l l of the north-south hallway.

Two panels use fourteen Trumbull E l e c t r i c

Company, Type T U , o r R, 120/208-~, three-phase breakers, having various current ratings.

Four panels use General E l e c t r i c Company

Type TF 136020, 60O-v, 3-pole breakers with several d i f f e r e n t current ratings.

There are t h r e e spare c i r c u i t breakers included.

S i x panels of heater c i r c u i t breakers a r e located along t h e south side of t h e east-west hallway.

Each panel contains four General E l e c t r i c

Company Type CCB, three-phase, c i r c u i t breaker mounting panels, seventeen of which a r e rated a t 600 v and seven a% 120/208 v.

The mounting panels

may contain up t o 20 c i r c u i t breakers but only 5 t o 8 a r e usually i n use.

Four of the mounting panels have Westinghouse De-Ion, F Frame,

Style 1222033 c i r c u i t breakers.

Thirteen panels use General E l e c t r i c

Company C a t No. TF 136020 f o r 600 v; f i v e use General E l e c t r i c Type ES-93 and two General E l e c t r i c Type EP-37,both rated a t 125 v.

494

bii

19.7.5 Heater Leads

E l e c t r i c a l leads f o r t h e process heaters i n t h e coolant c e l l a r e multi-conductor No. 19/22 Type TW cable run i n t r a y s and conduit from t h e heater control equipment t o a junction box i n t h e special equipment room.

From t h i s box, multi-conductor No. 19/22 RR cable i s run

i n t r a y s t o t h e equipment i n the c e l l . E l e c t r i c a l leads f o r heaters i n t h e reactor c e l l are multi-conductor No. 19/22 Type TW cable, l a i d i n t r a y s between t h e heater cont r o l equipment and junction boxes i n t h e south e l e c t r i c service area. The leads f o r the drain tank c e l l a r e i d e n t i c a l except that the junct i o n boxes a r e located i n the north e l e c t r i c service area.

The con-

nections between t h e junction boxes and t h e c e l l equipment are made with mineral-insulated, copper-sheather cables carrying t h r e e No o r 1 2 wires.

These pass through the c e l l w a l l s i n 3/4-in. pipe s i z e

penetrations described i n Section 19.8, following.

The heater leads

passing through each penetration a r e l i s t e d i n Table 19.11. Inside the c e l l s t h e cables a r e run i n square duct, e i t h e r t o junction boxes o r t o special 6OO-v, 5O-amp, metal-and-ceramic, female disconnects.

The disconnects, as i l l u s t r a t e d i n Figure 19.8,

are mounted i n t h e c e l l s convenient t o the heater served and a r e located i n a manner t o f a c i l i t a t e remote manipulation.

The c e l l

ends of the cables a r e sealed with brazed bell-end housings.

The

outside ends a r e sealed with a General Cable Co. insulating cap and threaded gland using a cold p l a s t i c sealing compound.

There are

eight spare leads t o the reactor c e l l and fourteen f o r t h e drain tank c e l l .

Some of the process heaters which a r e designed f o r removal and replacement have male, 6OO-v, 5O-amp, 3-wire disconnect plugs mounted d i r e c t l y on t h e removable u n i t .

The connection between t h e matching

female disconnect and t h e porcelain terminal blocks i n t h e junction boxes inside t h e c e l l i s made w i t h ceramic-beaded nickel a l l o y 99 wire, sheathed i n 1/2-in. OD f l e x i b l e s t e e l hose. Permanent heaters have t h e same type of f l e x i b l e leads connected d i r e c t l y t o the heaters.

The leads pass through junctions, where

t h e heaters a r e connected i n p a r a l l e l , and continue t o terminate i n

495 Unclassified ORNL DWG 64-8852

'cp, i

Disconnect Plug

Ceramic Beads Copper Conductors Conductor

I Disconnect Receptacle Ralco Mfg. Co.,No. 10 AECR, &-€imp,

6oo-vAc'

3 Pole.

Lead Brazed t o Terminal '%ish Spine" Ceramic

Beads

'w"C8bh End s d . C e r a m a ~ e a lCO. NO. &5BoU0-3 TWO 3/4-in.

Locknuts

Threaded elana General Cable Corp. No. 434

3/c No. 12 % Cable I" c

Figure 19.8.

Male and Female Electrical Disconnects for Heater Leads Inside Cells.

496 Table 19.11 Heater E l e c t r i c a l Lead C e l l Wall Penetrations PENETRATION R-2 DISCONNECT No.

TRAY

- REACTOR CELL

LENGTH*

SLEEVE No.

H520-J+S

~520-35

45 44 45

~520-25

~52c-1~

H520-4

H520-3 ~520-2

35 37

H200-2

36 36 36 36

FP-4

~200-7

~520-1 H520-5

4 5 6 7 8 9 10 11

13 14

H200-SP

H520-7S H520-6S

41 41

H200-1

H100-2

H100-1

H520-7

39 35

FP-5

~200-8

FCC-2

43 43

H520-6

center

H520-5S H2W-4 ~ 2 0 03H200-6 FP-SP ~200-9

Hx3 Hx2

eal

center center

* Estimated length

15 16

27 28

35 37

CABLE SIZE

3/c

1 0.

. 12

497

Table 19.11 Cont'd. DISCONNECT No.

TRAY

LENGTH

SLEEVE No.

HXL

center

H200-10

center

PE-1

east

34 35 36 37 38 39

FP-1 ~200-5 FP-2

27 29 24

31 31 31

PE-2

FP-3

43 44

PE-3 H200-10

center

H200-11

center

PENrmRATION R-3 DISCONNECT No.

TRAY

LENGTH

C A B U SIZE

>.1 2

41 42 1

- REACTOR CELL SLEEVE No.

C B U SIZE

H i Level Gamma

3 4 5 6

RFI-SP1

47 47 48

R2-2 ~2-3

~3-1

7 0

9 10 11

R2-1

3/c No. 10

center

45 31 37 43

3/c No. 10

LIFP-1

center

16 17

3/c No. 12

~3-2

west

3/c No. 10

H201-SP1

west

H201-3

west

H102-1

center

Rl-1

498

Table 19.11 Cont’d.

LENGTH

SLEEVE No.

57 56 46

LIFP-2

38 37 39 33

~101-3

~201-9

48 47

DISCONNECT No. RH-SP2

R3- 3 ~201-7 H201-4 H102-IS Rl-2

TRAY

wer I

center

~201-8 ~ 2 0 15-

20 21

23 25

3/c No. 12

m-SP3

=-3

LIFP-3

m02-3

34 39

H102-4

H102-2

H201-2

Rcc -1

49 54

H201-SP2

33 34 35 36 37 38 39

m02- 5

center

37 39

41 43 44

mol-1

H201-1

west

~201-6

3/c No. 10

mol-2

3/c No. 12

43 44

~ ~ 1 0 3

CABLE SIZE

- I

-.b.'

499

Table 19.11 Cont'd. WEST SIDE - DRAIN TANK CELL m T E R No.

FVl07-3 H108-3

67 71 74 73 67 63 66 66 64 69 67 66 67 62 65 66 69 67 66 61

H108-SP

FD2-4 FVl08-2

63 63

FVlO8-3 ~~108-1 FD2-SP2

~103 FFT- 2 FFT-SP1 FFT- 3 FFT-4 ~107-1

~107-2

H107-3 H 1 0 7-SP FFT-6 FFT- 5 ~108-1 FD2-2 ~108-2 FD2-SP1 FD2-3 ~~107-2 ~~107-1

H110-1

F D ~5FD1-3

H109-SP ~109-2

~~109-1 FV109-3

END CONNECTION

LENGTH

60 65 59 63 64 58 58 57 57

CABLE SIZE

3/c No. 10

disconnect

disconnect junct . box disconnect

i i

t 4

junct . box disconnect

junct box

disconnect

500 Table 19.11 Cont'd. HEATER No.

UNGTH

END CONNECTION

~~109-2 FD1-4

54 57 58

disconnect

FD1-SP1 m10-2

junct box disconnect

FD1-SP2

61 61 50 50 51

junct box disconnect

FD~-6

junct box

FD~-7

~106-1

45 46 41

mO9-3

m10-3 mo9-1 FD~-5

mo6-2 HLO6-3

CABLE SIZE

EAST SIDE - DRAIN TANK CELL HEATER No.

DCC FFT-1 FFT-SP2 FFT-8

H104-1 R104-2 H104-3 FFT-7 FD2-1 FD2-SP3 H105-SP

mo5-4 ~105-1

FD2-8

mo5-2 mO5-3 FV104-3

LENGTH

END CONNECTION

53 53 48

44 45 46 47 50

46 46 45

44 46 43 44 45

CABLE SIZE

disconnect

junct box

501

Table 19.11

Cont'd.

HEATER No.

LENGTH

FV104-2A FV104-1

44 47

F D ~7-

H105-4 ~ ~ 1-025~

44 44 43

~~105-1

H104-5 H104-SP

44 47

~ ~ 1- 02 5~

FVl05-3

FV104-6

FD~-6

46 43 47

Hl04-7S

FD1-2

H106-4

~~106-1

FV106-2D

36 45 43 36

FV106-3

~~106-2~

36 37

FV104-2D

H104-7

FDl-SP3 FD1-1

~106-SP

END CONNECTION

CABI;E SIZE

3/c N o . 12

junct

. box

disconnect

r )

502 male plugs, as i l l u s t r a t e d i n Figure 19.9.

These a r e plugged i n t o t h e

female disconnect f i t t i n g s which a r e t h e terminus of t h e mineral-insulated cables brought i n t o t h e c e l l . Table 19.11 a l s o l i s t t h e mineral-insulated cable data f o r each heater lead, including t h e length, wire s i z e and type of terminal used.

When single-phase heater c i r c u i t s a r e required, one w i r e of

the three-wire cables i s not connected.

19.8 C e l l Wall Penetrations f o r E l e c t r i c a l Leads Copper o r s t a i n l e s s s t e e l sheathed, mineral-insulated cables a r e used f o r t h e e l e c t r i c a l leads passing through t h e walls of t h e r e a c t o r containment and d r a i n tank c e l l s .

The cable passes through

individual pipe sleeves with compression f i t t i n g s a t each end t o form a leak-tight j o i n t around the sheaths.

Although gas d i f f u s i o n through

t h e mineral i n s u l a t i o n i s considered negligible, t h e sheaths a r e a l s o sealed a t each end.

The number of cable sleeves a t each penetration

i s indicated i n Tables 19.12 and 19.13.

The heater leads i n pene-

t r a t i o n s I1 (R ) and I11 (Re) are l i s t e d i n d e t a i l i n Table 19.11.

19.8.1 Sheathed Cable. The mineral-insulated sheather cable i s manufactured by t h e General Cable Company.

The catalog numbers f o r t h e various numbers

of conductors and wire s i z e s are l i s t e d i n Table 19.14.

Copper

sheathing i s used on a l l M I cable leads. The r e a c t o r c e l l end of a sheath i s sealed with a brazed-on Ceramaseal M I cable pothead, Cat. No. 805~-0110, o r 0111, e t c .

The

end of t h e sheath outside t h e c e l l i s sealed with a screwed-on pothead f i l l e d with a cold-setting p l a s t i c i n s u l a t i n g compound.

See ORNL

DWg. E-MM-Z-56238. 19.8.2

Cable Sleeves.

The M I cable passes through t h e c e l l w a l l s i n individual sleeves

of 3/8-in. IPS t o 1-in. IPS, depending on t h e cable s i z e . have a minimum of a 2-1/2-in.

These pipes

o f f s e t a t t h e midpoint through t h e

c e l l w a l l t o prevent r a d i a t i o n from streaming through t h e opening.

503 Table 19.12

Summary of E l e c t r i c a l Lead Penetrations i n Reactor Cell

MSRE Pene-

Former Penet r a t i o n No.

t r a t i o n No. I1

I11

Number of Sleeves

Function

Electrical

Sleeve Size IPS Schd. 40

6 38 6 38 7

1in.

314 i n . 1in.

314 i n . 314 i n .

Thermocouples

112 i n . 318 i n .

Instrumentation

318 i n .

XXIII

Thermocouples

318 i n .

Table 19.13 Summary of E l e c t r i c a l Lead Penetrations i n Drain Tank C e l l

MSRE Sleeve Numbers

Function

A-1 t o A-36

Table 19.14

Instrumentation Instrumentation Thermocouples Thermocouples Thermocouples Electrical Electrical Electrical Electrical Electrical Electrical

B-1 t o B-36 C-1 t o C-36 D-1 t o D-36 E-1 t o E-36 A-37 t o A-60 B-37 t o B-60 c-37 t o c-60 D-37 t o D-60 E-37 to E-60 F-37 t o F-60

General Cable Company M I Cable Numbers

Number Conductors

Wire Size

Sleeve Size i n . IPS

Gen. Cable C a t . No.

4 3 7 3 3

112

12 10

314 314 314

387 434 449

480

621

504 The cable sleeves a r e grouped t o pass through a poured concrete

U -3

plug mounted i n e x i s t i n g penetrations i n t h e r e a c t o r containment vessel w a l l , or, i n t h e case of t h e d r a i n tank c e l l , a r e arranged on a rectangular g r i d i n t h e poured concrete of t h e 3-ft-thick east

w a l l of t h e c e l l . sleeve layout.

See ORNL Dwg D-KK-C-40947 f o r t h e d r a i n tank c e l l

All d r a i n tank c e l l cable sleeves a r e 3/4-in. IPS.

The cable sleeves have pipe couplings screwed t o each end t o accept a General Cable Company compression gland.

This f i t t i n g con-

sists of a compression sleeve and nut t o e f f e c t a l e a k - t i g h t s e a l around t h e M I cable sheath.

See ORNL D gs D-EJH-B-40539 and Figure 19.9. .

19.8.3 Reactor C e l l Penetration Plug and Sleeve. Existing r e a c t o r containment vessel penetrations consist of sleeves, about 23-in. ID, with one end welded t o t h e inner containment vessel w a l l and t h e other end t o t h e w a l l of t h e outer vessel. A corrugated bellows midway between t h e ends permits r e l a t i v e movement

between t h e two vessels, as shown i n Figure 19.10 and on ORNL Dwg

D-KK-D-40976. A plug, about 22-3/4-in.

OD x 3 f t 5 i n . long, f i t s i n t o t h e

above-mentioned sleeve, and i s welded t o it on t h e outside end. T h i s plug c o n s i s t s of a carbon s t e e l sleeve, about 22 i n . I D of 3/8-in.

w a l l thickness, with end p l a t e s welded t o it through which t h e cable sleeves pass.

These sleeves a r e welded t o t h e p l a t e s a t both ends,

using a trepanned groove a t each weld.

The space between t h e cable

sleeves i n s i d e t h e plug i s f i l l e d with concrete.

E-BB-D-41864.

See ORNL Dwg

505

506

L;I

BUILDING SERVICES

20.

-3

20.1 Potable Water The source of potable water f o r Building 7503 i s b r i e f l y described i n t h e discussion of the site, Section 3 and shown i n Figure 3.3.

The

6 water i s normally obtained from the two 1.5 x 10 -gal reservoirs e a s t of the s i t e , with flow from east-to-west i n t h e 12-in. water main along These reservoirs have a maximum water l e v e l elevation of

7500 Road.

1,055 f t , providing a maximum pressure of about 93 psig a t the 840-ft elevation i n Building 7503.

Potable water can a l s o be provided by

west-to-east flow i n t h e 6-in. main along 7500 Road, as indicated schematically i n Figure 20.1.

Both sources connect t o t h e same 6-in.

t e e supplying the building. The 6-in. potable water main enters the north end of Building 7503 a t about t h e 840-ft elevation, where it then divides i n t o two major

branches.

One &-in. main supplies all building services, such as water

closets, lavatories, sinks, showers, drinking fountains, e t c

. The

other &-in. main provides water f o r t h e f i r e protection system, as discussed i n Section 20.10. 20.2

Process Water

Process water i s supplied t o the MSRE from t h e same potable water mains a t 7500 Road, but through a d i f f e r e n t 6-in. main leading from the road t o the east side of Bldg. 7503, as shown i n Figure 20.1.

There

are two shutoff valves outside the building a t the 848-ft elev.

back-flow preventer i s i n s t a l l e d i n t h e l i n e j u s t inside the building t o r e l i e v e water t o the building drain i n event t h e building process

water pressure should exceed t h e supply pressure.

Piping connections

and valves are provided f o r i n s t a l l i n g a spare back-flow preventer should t h i s be found necessary. Distribution of the process water t o t h e MSRE systems i s discussed i n Section 15 and shown on t h e flowsheet, Figure 15.1

D-AA-A-40889).

(ORNL Dwg

Unclassified ORNL DWG 64-9108

mom x-10 I

6 in.

,6 in.

332-e plug

/Potable

1,500,000-g&l.

Water

Water Tanks (6

To Outside Siemese Corm l-

_____

-I

_--------

Eav845f%,

.6 in.

- -4x

“I I To Hose 1 Cabinets I

To Sprinklers

To Building Services

I II I I 1 I I

6 in.

i I I

/6 in.

RLgure 20.1.

Water Services

to Building

7503.

in.

508

Building Lighting

20.3

’ i

The 13.8-kv feeder l i n e s supplying e l e c t r i c power t o t h e MSRE s i t e

a r e b r i e f l y described i n Section 3 and shown i n Figure 3.4.

A b a n k of

three 25O-kva, 13.8-kv t o 48O-v, transformers located on the e a s t side of B l d g 7503 supplies power f o r i n t e r i o r and e x t e r i o r lighting, air conditioners, and general o f f i c e and building uses. There a r e two main d i s t r i b u t i o n panels.

Panel No. 1, located a t

t h e 840-ft level, has a capacity of 750 amps and supplies t h e 3-ton and 10-ton cranes, the control room a i r conditioning equipment, the main f l o o r u n i t heater and fan, and the basement area u n i t heat and fan.

This panel a l s o provides power f o r a 48O-v/12O-v-24O-v

supplying Panel 1 A .

transformer

This 750-m panel d i s t r i b u t e s power t o the control

room panels, lighting, the high-bay area roof vent fans, the sump p i t vent fan, and t o Panel lAl, which supplies t h e remainder of the l i g h t -

ing circuits. Panel No. 2, of 325-amp capacity, supplies t h e remaining u n i t heaters and vent fans and t h e 480-v building o u t l e t receptacles. The e l e c t r i c building services a r e shown on ORNL Dwg D-KK-C-41134. 20.4

Fencing

The MSRE s i t e i s a non-classified area and security guards are not required.

An 8-ft Cyclone fence serves as a perimeter enclosure.

Vehicular gates a r e provided a t the northwest and southeast corners and a 30-ft-wide main gate i s located a t the north end of the building. 20.5

Steam Supply

Saturated steam a t 240 psig i s supplied t o Building 7503 f r o m t h e X-10 power plant through a 6-in. main as shown i n Figure 3.5.

The

pressure i s reduced t o 50 psig a t a reducing valve s t a t i o n on t h e east side of t h e building.

The main then enters t h e building a t about the

842-ft elevation, where it then divides i n t o numerous branches supplyi n g steam throughout t h e building. discharged t o the building drains.

Condensate i s not returned but i s

509

b.,

20.6

Roof, Foundation and Floor Drains

P Storm water from t h e roof drains flows through a 6-in. l i n e t o a catch basin located west of Bldg 7503 with an i n v e r t elevation of

837 ft, as indicated i n Figure 20.2.

A12-in. reinforced concrete

pipe c a r r i e s t h e water from t h e basin t o a drainage area west of t h e building, leading t o Melton Hill Branch. The various f l o o r drains, etc., emptying i n t o t h e sump room a r e l i s t e d i n Table 14.1. i

As described i n Section 14, sump pumps d e l i v e r

t h e water t o another catch basin, with an i n v e r t elevation of 843 f t , t o d r a i n through a 12-in. reinforced concrete pipe t o t h e same drainage area mentioned above. 20.7

Sanitary Disposal

The Building 7503 s a n i t a r y waste system piping i s directed t o a s e p t i c tank located about 100 f t west of t h e building a t an elevation of 840 f t .

The drainage f i e l d i s outside t h e perimeter fencing and

about 250 f t west of t h e building. 20.8

Air Conditioners

The main control room and t h e data processing room a r e a i r conditioned by a Trane Company steam-heated c o i l , blower and f i l t e r u n i t located a t t h e 852-ft elevation i n t h e hallway south of t h e control room, and by an evaporator c o i l i n t h e discharge ducting from t h e heater u n i t .

This direct-expansion c o i l i s supplied with Freon-12

from a l5-ton Worthington 2vc-6 reciprocating campressor-condenser u n i t located a t t h e 840-ft elevation. Two 5-ton Trane Company " C l i m a t e Changers", located a t t h e 852-

f t elevation, air condition t h e o f f i c e areas.

20.9

Fire Protection System

The e n t i r e Building 7503 area, with t h e exception of t h e shielded c e l l s , t h e switch house, t h e f a n house, and t h e b a t t e r y room, i s prot e c t e d by a Grinnell Company water s p r i n k l e r system i n s t a l l e d as p a r t

510

Unclassified ORNL IXJG 64-9109

figure 20.2.

Schematic Magram Building 7503 Drainage System

511

ors4 -4

of t h e MSRE project.

Water f o r t h e system i s obtained from the 6-in.

potable water l i n e entering t h e north end of the building, see Figure 20.1.

A b i n . Siamese double-hose connection i s provided outside the

north end of t h e building t o a t t a c h a booster source of water f o r the sprinkler system. The 6-in. potable water main a l s o has a kcin. branch connection j u s t inside the building with 4-in. shutoff and check valves, t o supply

s i x f i r e hose cabinets. -4

The 4-in. hose supply can a l s o be augmented

from t h e booster connection outside the building.

Under normal conditions t h e sprinkler system i s valved off from t h e water supply, t h e consequences of inopportune release of water being more serious than the short delay i n opening the valves i f

water i s needed.

513

APPENDIX

515 LIST OF REFEENCES USED I N PART I

H. G . MacPherson, Molten-Salt Breeder Reactors, ORNL-CF-59-12-64 (Jan. 12, 1960).

L . G . Alexander, e t a l . , Experimental Molten-Salt-Fueled Power Reactor, ORNL-27q m a r c h 8, 1960).

J. A. Swartout, L e t t e r t o R. M. Roth, Request f o r Directive CR-316, Molten S a l t Reactor Experiment (Mar. 17, 1961)

S . R. S a p i r i e , AEC Directive CL-262, Molten S a l t Reactor Experiment, Bldg. 7503, Oak Ridge, Tennessee (April 28, 1961).

F. F . Blankenship, Additional Estimated Physical Properties of MSRE Fuel, ORNL-MSR-63-30 (July 17, 1963).

S . E . Beall, e t a l . , MSRE Preliminary Hazards Report, ORNL-CF-61-2-46

(Feb. 28, 196g.-

-fi

-'u

S. E. Beall., e t a l . , MSRE Preliminary Hazards Report Addendum No. 1,

-N%F,Staff, MSRE Preliminary Hazards Report Addendum No. 2, ORNL CR-61-2-46 (May 8, 1962).

W . B. C o t t r e l l ( e a . ) , (Classified "Secret"), ORNL-1407 (Nov. 24, 1952).

10.

W . B. C o t t r e l l , e t a l . , The A i r c r a f t Reactor Test Hazards Summary Report, O R N L - ~n ~a n~ . 19, 1955).

11.

R. B. Briggs, Molten-Salt Reactor Program Semiannual Progress Report f o r Period Ending Dee. 31, 1963, ORNL-3626.

12.

L. F . Parsley, MSRE Reactor Containment Vessel Design C r i t e r i a , ORNL MSR-61-70 (June 23, 1961).

L. F. Parsley, MSRE Containment Vessel S t r e s s Studies, ORNL MSR-62-15 (Feb. 2, 1962).

14.

L. F. Parsley, Consequences of a S a l t S p i l l i n t o t h e Bottom of t h e MSRE Containment Vessel. ORNL MSR-62-12 (Jan. 23. 1962).

R. B. Lindauer, MSRE Process Flowsheet Discussions, ORNL MSR-62-4 (Jan. 10, 1962).

16.

R. B. Lindauer, Revisions t o MSRF: Design Data Sheets, Issue No. 8, O m CF-63-6-30 (June 12, 1963).

Om-CF-61-2-46

(August 14, 1961).

References, Cont 'd.

516

17.

R. B. Lindauer, MSRE Line Schedule, Revision No. 3, ORNL MSR63-36 (Oct. 14, 1963).

18.

E . H . B e t t i s ( e a . ) , MSRE Component Design Report, ORNL MSR-61-67 (June 20, 1961).

W . B. McDonald, Fabrication Specifications, Procedures and Records f o r MSRE Components, ORNL MSR-62-3 (Jan. 23, 1962).

20.

A. L. Boch, e t a l . , The Molten S a l t Reactor Experiment, paper presented a t I n t e r n a t i o n a l Atomic Energy Symposium, Vienna, Austria, Oct. 23-27, 1961.

21.

Contract, National Carbon Company, No. AT (40-1) -2882, Requisition No. 61-2189 ( J u l y 14, 1961), and Order No. 0R62-1746, Requisition No. 62-1723 (June 14, 1962).

22.

R. B. Briggs, et a l . , Modifications t o Specifications f o r MSRE Graphite, ORNL CFX3-2-18 (Feb. 14, 1963).

H. G . MacPherson, Memo t o A. M. Weinberg, t h e MSRE, (Nov. 25, 1960).

24.

R. C . Schulze, e t a l . , INOR-8-Graphite-Fused-Salt Test, - ORNL-31247JGe 1, 1961).

25.

W . H. Cook and A. Taboada, Oxygen Contamination i n t h e MSRE from Graphite and INOR-8,ORNL MSR-62-38 (May 10, 1962).

26.

S . E. Beall, Procedures f o r Cleaning and Purging MSRE Graphite, ORNL MSR-61-148 (Dec. 11, 1961).

27.

I . Spiewak, Proposed Program f o r Purging and Cleaning MSRE Graphite, ORNL MSR-61-144 (Dec. 4, 1961).

28.

B. W. Kinyon, Effects of Graphite Shrinkage i n MSRE Core, ORNL CF60-9-10 (Sept. 2, 1960).

S. E. Moore, Memo t o R. B. Briggs, April 26, 1962.

Graphite Problems i n Compatability

MSRF: Core Graphite Shrinkage,

30.

W. L. Breazeale, Preheating of Graphite Core i n MSRE, ORNL MSR-61-99 (Aug. 15, 1961).

J. R. Engel and P. N. Haubenreich, Temperatures i n t h e MSKE Core During Steady-State Power Operation, ORNL TM-378 (Nov. 5, 1962).

R. Van Winkle, Temperature Rise i n t h e MSCR Graphite Due t o Decay Heat from Absorbed Fuel S a l t - MSCR Memo No. 4, ORNL CF-61-9-59 (Sept. 25, 1961).

Ref e rence s , C ont ' d

517

J. H. Crawford, E. G. Bohlman and E. H. Taylor Re 01% of the MSRE Graphite Committee, ORNL CF-61-1-54 (Jan 6-i

L. F. Parsley, MSRE Core No. 1 Design J u s t i f i c a t i o n , ORNL CF60-9-89 (Sept. 28, 1960).

H. F Poppendiek and L. D. Palmer, Forced Convection Heat Transfer Between P a r a l l e l Plates and Annuli with Volume Heat Sources within t h e Fluids, ORNL-1701 (May 11, 1954).

L . F. Parsley, L e t t e r t o A . L . Boch, Temperature Rise Effects i n MSRE Cores with Round and F l a t Fuel Channels (June 10, 1960).

J. E. Mott, Hydrodynamic and Heat Transfer Studies of a Full-scale Reentrant Core (HRT). O€"G CF-58-8-54 (Aug. 8, 1958).

R. J. Kedl, Pressure Drop Through t h e MSRE Core, ORNL MSR-62-71 (Sept 59 1962)

R. J. Kedl, S a l t Flow Rate Through Core Support Flange, ORNL MSR64-4 (Jan. 24, 1964)

40.

R. B. Briggs, Molten-Salt Reactor Program Semiannual Progress Report f o r Period Ending Aug. 31, 1962, ORNL-3369 (Dec. 4, 1962).

41.

R. J. Kedl, Holes f o r Starved Fuel Channels i n t h e MSRE Core, ORNL ,WR-63-6 (Feb. 21, 1963).

42.

R. D. Sterling, Letter t o E. S. B e t t i s , power System, Bldg 7503 (Nov. 3, 1961).

J. A . Westsik, Drain Tank Capacity Requirements f o r MSRE, ORNL MSR-6'1-141 (Dec. 5 , 1961).

44.

H. R. Payne, Mechanical Design of t h e MSRE Control R o d s and Reactor Access Nozzle, OR% MSR-61-158 (Circa, June, 1961).

C . W. Nestor, Jr., Preliminary Calculations of Heat Generation and Helium Production i n MSRE Control Rods, ORNL MSR-61-118(Sept. 26, 1961).

46.

P. N. Haubenreich, Importance of Errors i n Measurement of Temperat u r e and Control Rod Position i n WEE, ORNL CF-63-8-43 (Aug. 14, 1963).

"Unfired Pressure Vessels", Section V I I I , ASME Boiler and Pressure Vessel Code, American Society of Mechanical Engineers, New York. (See t e x t f o r e d i t i o n date, i f important).

48.

"General Requirements f o r Nuclear Vessels, Case l27ON", Interpretations of ASME Boiler and Pressure Vessel Codes, American Society of Mechanical Engineers, New York. (See t e x t f o r revision number).

Review of MSRE E l e c t r i c a l

References, Cont'd.

518

"Containment and Intermediate Containment Vessels, Case l272N", Case I n t e r p r e t a t i o n s of ASME Boiler and Pressure Vessel Codes, American Society of Mechanical Engineers, New York. (See t e x t f o r revision number)

"Nuclear Reactor Vessels .and Primary Vessels, Case 1273Nf1, - -Case I n t e r p r e t a t i o n s of ASME Boiler and Pressure Vessel Codes, American Society of Mechanical Engineers, New York. (See test f o r revision number).

' ~ ~ Interpretations "Special Equipment Requirements, Case 1 2 7 6 ~ Case of ASME Boiler and Pressure Vessel Codes, American Society of Mechanical Engineers, New York. (See t e x t f o r revision number).

"Nickel-Molybdenium-Chromium-IronAlloy, Case 1315", Case Interpret a t i o n s of ASME Boiler and Pressure Vessel Codes, American Society of Mechanical Engineers, New York. (See t e s t f o r revision number),

53.

R. W. Swindeman, Design Stresses for Wrought and Annealed INOR-8 Between Room Temperature and 1400°F, ORNL MSR-60-31.

W. L. Breazeale, Gamma Heating of Reactor Vessel Hanger Rods f o r MSRE, o m MSR-~~J

W. L. Breazeale, Re-evaluation of Gamma Heating i n Proposed Reactor Vessel Hanger Rods f o r MSRE, ORNL MSR 61-52 (May 12, 1961).

J. H . Westsik, Memo t o R. B. Briggs, Review of Flow Design t o t h e MSRE Thermal Shield ( J u l y 23, 1962).

57.

W . C . Ulrich, Memo t o S. E. Beall, Loss of Cooling Water Flow t o t h e MSRE Thermal Shield (Feb. 20, 1963).

E. C. Miller, Memo t o F. L. Rouser, MSRE Reactor Vessel Thermal Shield Drawings E-KK-D-40722 - 40730 (May 8, 1962).

60.

H. C . Claiborne, High-Energy Neutron Flux i n t h e Containment Vessel of t h e MSRE, ORM, MSR-62-27 (March 19, 1962).

p. G. Smith, Water Test Development of Fuel Pump f o r t h e MSRE, ORNL (Mar. 27, 1962).

"-79

, Purchase Order No. 74Y-47524 ( J u l y 11, 1962).

61.

General Alloys, Boston, Mass.

62.

Lukins S t e e l Company (Coatesville, Pa.), Purchase Order No. 9Ty-87622, October 30, 1961.

Westinghouse E l e c t r i c Corp.

64.

Specification of Drive Motor f o r MSRE Primary Pump, ORNL Job Specification 169-101 (Mar. 15, 1961).

, Purchase Order No. 63~-57698,May 29, 1961.

LJi

References, Cont'd.

519

Specification f o r Drive Motor f o r MSRE Secondary Pump, ORNL Job Specification 169-124 (Oct. 11, 1961).

66.

A. G. Grindell, e t a l . , Memo t o E . S . B e t t i s , Design Memo f o r MSRE Pumps (Dec. 15, 1961).

Ralph H. Guyman, Memo t o R. B. Briggs, Fuel and Coolant Pump O i l Systems (Jan. 15, 1963).

68.

A . G. Grindell, Back-Diffusion Experiment on PK-P Pump, ORNL MSR-61-50 (May 11, 1961).

G. H. Llewellyn, Gamma, Beta and Neutron Heating of MSRE Pump Lubrication Shield, ORNL (2-61-1-38 (Jan. 16, 1961).

C. W. Nestor, Influence of Residence Time D i s t r i b u t i o n of FissionProduct Decay i n t h e MSRE Pump Bowl and Off-Gas Line, ORNL CF 61-6-85 (June 23, 1961).

71.

I . Spiewak, Xenon Removal i n t h e MSRE Pump Bowl, ORNL MSR-60-8 ( o c t . 7, 1960).

S. J. B a l l , MSRE Pump G a s Purge System Study, ORNL MSR-61-3

(Jan.

9, 1961).

P. H. Harley, Pump Bowl Overflow Line, ORNL MSR-62-2 (Jan. 10, 1962). C

. H. Gabbard, Air Cooling Requirements of MSRE Primary Pump Bowl,

ORNL MSR-61-28 (Mar. 23, 1961).

C. E. Gabbard, E l e c t r i c a l I n s u l a t i o n f o r t h e MSRE Fuel and Coolant Pump Drive Motors, ORNL MSR-62-10 (Feb. 1, 1962).

D. W , Vroom, Primary Pump Motor Background Radiation Level a t 10-Mw, ORNL MSR-61-49 (May 10, 1961).

A, G. Grindell, Specification of a Lubricant f o r MSRE Pumps, ORNL MSR 60-37 (Nov. 18, 1960).

L. V, Wilson, MSRE Fuel Pump Coolant O i l Temperature A f t e r Cessation of O i l Flow, ORNL MSR 61-84 ( J u l y 20, 1961).

C . H. Gabbard, Estimated Flow S t a r t u p Transient of t h e MSRE Fuel System, ORNL MSR 61-133 (Nov. 14, 1961).

80.

R. B. Briggs, Molten-Salt Reactor Program Progress Report f o r

Period from August 1, 1960 t o February 28, 1961, ORNL-3122 (June c

-tu'

20, 1961).

References

, Cont ' d.

520

81.

A. G. Grindell and P . G. Smith, MSRE Prototype Pump Shaft Seizure, ORNL MSR-62-67 (Aug. 27, 1962).

82.

D. E. Gladow, MSRE Primary Pump; Analysis of S t r e s s i n Impeller Bowl Due t o Axial Loading, ORNL MSR-60-60 (Sept. 3, 1960).

83.

T. B. Fowler, Generalized Heat Conduction Code f o r t h e IBM 7090 Computer, ORNL CF-61-2-33 (Feb. 9, 1961).

84.

F. J. Stanek, S t r e s s Analysis of Cylindrical S h e l l s , ORNL CF-58-9-2 ( J u l y 22, 1959).

F. J. Startek, S t r e s s Analysis of Conical S h e l l s , ORNL CF-58-6-52 (Aug. 28, 1958).

86.

F. J. W i t t , Thermal S t r e s s Analysis of Cylindrical S h e l l s , ORNL CF-59-1-33 (Mar. 26, 1959).

F . J. W i t t , Thermal Analysis of Conical Shells, OFNL CF-61-5-61

(July 7, 1961)

88.

C . H. Gabbard, Thermal-Strain and Strain-Fatigue Analyses of MSRE Fuel and Coolant Pump Tanks, ORNL TM-78 (Oct. 3, 1962).

R. B. Gallaher, Thermal S t r e s s Analysis of t h e Sampler-Enricher Attachment t o t h e MSRF: Fuel Pump, ORNL MSR-62-16 (Feb. 5, 1962).

90.

W. C. TJlrich, Fuel Pump Main Support Members, Memo t o R. B. Briggs, ORNL MSR-61-159 ( c i r c a June, 1961).

91 *

J. M. C o r n , Memo t o R. B. Briggs, F l e x i b i l i t y Analysis of MSRE Piping, April 24, 1962.

92.

Specification f o r Primary Heat Exchanger f o r MSRE, ORNL Job Specification 80-109 (Dec. 22, 1960).

Tentative Specification f o r Fabrication of MSRE Heat Exchanger Tube Bundle, ORNL Job Specification 61-182 (Sept. 10, 1962).

Specification f o r Brazing of t h e Tube Bundle f o r t h e MSRE Heat Exchanger, ORNL Job Specification 80-167 ( J u l y 16, 1962).

R. G. Donnellv. Reauirements f o r Welding Tube-to-Tube Sheet J o i n t s f o r MSRE Prim& " H e a t Exchanger and Heat Exchanger Samnle ORNL . - , MSR-62-66 (Aug. 29, 1962). ~

R. G. Donnelly, Primary Heat Exchanger Tube-to-Tube Sheet Welding and Subsequent Machining, ORNL MSR 62-39 (May 16, 1962).

97.

R. G . Donnelly, Design Revisions f o r t h e Primary Heat Exchanger Tubeto-Tube Sheet J o i n t s , ORNL MSR-62-23 (March 1, 1962).

References, Cont'd.

521

R. G. Connelly, Brazing Alloy f o r t h e Primary Heat Exchanger Tubeto-Tube Sheet J o i n t s , ORNL MSR-62-6 (Feb. 12, 1962).

W. C. Ulrich, Hydrostatic Test Pressures f o r MSRE Primary Heat Exchanger, Memo t o C. K. McGlothlan, March 12, 1963.

100.

J. C . Amos, R. E. MacPherson and R. L. Senn, Preliminary Report of Fused S a l t Mixture 130 Heat Transfer Coefficient Test, ORNL CF-58-4-23 (April 2, 1958).

101.

D. Q. Kern, Process Heat Transfer, p. 834, Figure 24, McGraw-Hill, New York, 1950.

102.

G. T. Colwell, Pressure Drops Through MSRE Heat Exchanger and Piping, Memo t o R. B. Briggs (Aug. 29, 1962).

103.

Standards of Tubular Exchanger Manufacturers Association, TEMA, 366 Madison Ave., New York, 1949.

104.

H. R. Payne, Reservoir f o r Fuel S a l t Drain Tank Cooling System Addendum t o MSR 61-67 (Ref. 18), Memo t o Distribution ( J u l y 11; 1961).

105.

J. C . Moyers, Design of Freeze Valves f o r MSRE, ORNL MSR 61-160 (Circa, June, 1961).

106.

American Standard Code f o r Pressure Piping, ASA B 31.1 American Society of Mechanical Engineers, New York.

107.

W . C . Ulrich, MSRE Pipe Support Calculations by R. E . Ramsey, Memo t o R. B. Briggs, (Jan. 28, 1963).

108.

R. B. Briggs, Molten-Salt Reactor Program Semiannual Progress Report f o r Period Ending Aug. 31, 1962, ORNL-3369 (Dec. 4, 1962).

log.

J. C. Moyers, Thermal Cycling T e s t of 3-l/2-in. Flanges. ORNL CF-61-2-38 (Feb. 2 , 1961).

110.

R. B. Briggs, Molten-Salt Reactor Program Semiannual Progress Report f o r Period Ending Jan. 31, 1963, 0RM;-3419 (May 24, 1963).

111.

J. C . Moyers, Design of Freeze Flanges f o r MSRF:, Memo t o R. B. Briggs, ORNL MSR-61-161 ( c i r c a June, 1961).

112.

R. E. Ramsey (Burns and Roe), MSRE Reactor Piping S t r e s s Analysis, Memo t o R. B. Briggs, ORNL MSR-61-157 ( c i r c a June, 1961).

113.

Sturn-Krouse, Inc Research and Consulting Engineers (Auburn, Alabama), Analyses and Design Suggestions f o r Freeze Flange Assemblies f o r MSRE, Report t o ORNL under Subcontract No. 1477, Novo 30, 1960.

- 1955,

and b i n . Freeze

References, Cont'd.

522

114.

M. Richardson, Development of Freeze Valves f o r Use i n t h e MSRE, ORNL TIU-128 (Feb. 28, 1962).

115.

R. B. Briggs, Operation of Freeze Valves i n t h e MSRE, ORNL MSR-63-47 (Dec. 12, 1963).

116.

R. L . Moore, MSRE Freeze Valve Control Circuitry, Memo t o Distribution (May 31, 1962).

117.

R. B. Brings. ~ _ _ , Molten-Salt Reactor Proaram Semiannual Progress Report f o r Period Ending J u l y 31, 1-96?, ORNL-3529 (Dec. 0 , 1963).

118.

W. Thomas Mullins, Activation Analysis of Heater Materials ( f o r MSRE), Memo t o M. Richardson (Oct. 16, 1962).

119.

J. R. Engel and B. E. Prince, C r i t i c a l i t y Factors i n MSRF: Fuel Storage and Drain Tanks, ORNL-TM-759 ( I n preparation).

120.

S t a t u s and Progress Report, Oak Ridge National Laboratory, p . 15, ORNL-3543 (Nov., 1963).

121.

R. E. Thoma and F. F. Blankenship, Relative Abundance of Phases i n t h e Frozen MSRE Fuel at Eauilibrium Conditions. ORNL MSR (Revised) 63-38 (Nov. 8, 1965).

122.

S . E . Beall, e t a l . , MSRE Reactor Safety Analysis Report, ORNL TM-732 (Augusx 1964).

123.

T. W . Pickel, MSRE Drain Times, ORNL MSR-62-97 (Dec. 17, 1962).

124.

L. F

. Parsley, MSRE Drain Tank Heat Removal Studies, OFU'JI,

CF-60-9-55 (Sept. 19, 1960). 125.

Vapor Condensing System Water and Gas Tanks, ORNL Specification XSP-120 (April 27, 1964).

126.

P. H. Harley, Drain Tank Furnace Tests, ORNL MSR 64-9 (Feb. 24,

127.

H. R. Payne, Weights of MSRE Fuel, Flush and Coolant Tanks, and Contents, Memo t o R. L. Moore (Jan. 29, 1962).

128.

R. B. Gallaher, MSRE Sampler-Enricher System Proposal, ORNL CF-61-5-120 (May 24, 1961).

129.

G. A. Cristy, S t r e s s e s and Loads i n t h e Sampler-Enricher Transfer Tube, Work Request A-70496-llD, L e t t e r t o E . S. B e t t i s (NQv. 13, 1961).

130

C. H. Gabbard, Hydraulic Performance of MSRE Coolant Pump, Memo t o A. G . Grindell ( J u l y 9, 1963).

1964).

’

References, Cont d.

131.

W. C. Ulrich, MSRE Radiator Design, ORNL CF-60-11-108 (Nov. 30, 1960).

132.

Roy C Robertson and S. E. Bolt, MSRE Heaters Summary of Preliminarv Studies Memo t o E. s. B e t t i s (Aug. 11, 1960).

133

W . B. McDonald, I n s u l a t i o n of Thermocouples on MSRE Radiator, Memo t o R. B. Briggs (Feb. 5, 1963)

134.

W. C . Ulrich, Hydrostatic Test Pressure f o r MSRE Radiator, Memo t o C . K. McGlothlan (April 9, 1963).

135

W. C Ulrich, MSRE Radiator A i r Flow Characteristics, ORNL MSR 61-18 (Mar. 8, 1961).

136.

W. C . Ulrich, Control of Eeat Removal Rate from MSRE Radiator, ORNL MSR 61-51 (May 12, 1961).

137

S. J. D i t t o , Control of MSRE Between 1 Mw and 10 Mw, ORNL MSR 63-23 (June 4, 1963)

138.

S. J. B a l l , Freezing Times f o r Stagnant S a l t i n MSRE Radiator Tubes, Memo t o J R. Tallackson (April 9, 1963).

139

R. E. Ramsey (Burns and Roe), Coolanit System S t r e s s Analysis, Memo t o R. B. Briggs, ORNL MSR-61-156 (Nov. 3, 1961).

140.

A. N. Smith, MSRE Cover Gas System, ORNL MSR 60-44 (Nov. 30, 1960).

141.

A. N. Smith, MSRE Cover Gas System Flowsheet, ORNL MSR 60-11 ( o c t . 7 ) 1960).

142.

P. N. Haubenreich, Oxygen Production by Fluorinelg (n, i n MSFE, ORNL m ~ - Q c . 2 3 ( m y 27, 1964).

143.

A. N. Smith, MSRE Cover Gas System, Design Memo C-3, Helium Dryer, Memo t o R. B. Briggs (Nov. 2, 1961).

144.

A . N. Smith, Helium Surge Tank, Design Memo C-4, Memo t o R. B. Briggs (Nov, 10, 1961).

145.

A. N. Smith, Leak Detector System, MSRE Cover Gas System, ORNL MSR 61-83 ( J u l y 27, 1961).

146.

P. P. Holz, Development of Six-Station Manifold Disconnect, ORNI, CF-61-5-117 (May 18, 1961).

147.

P. P. Holz, S t a t u s of Small Pipe Disconnects f o r MSRE, ORNL m-60-9-102 (Sept 27, 1960)

523

) React ion

148.

A . N. Smith, MSRE Charcoal Beds, ORNL MSR-61-101 (Aug. 17, 1961).

References, Cont'd.

524

149.

R. B. Stevenson, Radiation Source Strengths i n t h e Expansion and O f f - G a s System of t h e ART, ORNL CF-57-7-17 (Nov. 18, 1957).

150.

J. 0. Blomeke and M. F. Todd, Uranium 235 Fission-Product Production as Function of Thermal Neutron Flux, I r r a d i a t i o n Time, and Decay Time, OW-2127, P a r t I, Vol. I (Aug. 19, 1957).

151.

a1 , Treatment of Off-Gas from t h e HW, KT 373, Solenberger, et 4 Memo t o W. E. Browning, Jr. (Nov. 13, 1958).

152.

R. D. Ackley and W. E. Browning, Equilibrium Adsorption of K r and Xe on Activated Carbon and Linde Molecular Sieves, ORNL CF-61-2-32 (Feb. 14, 1961). F i r e Resistant High-Efficiency A i r F i l t e r - up t o 25O?F, ORNL Specification EP-26. Design Criteria Containment and Building Ventilation System, Building 7503, ORNL Work Request A-70496-llD (Jan. 28, 1963). F . L. Culler, Criteria f o r Handling Melton Valley Radioactive Wastes, ORNL CF-61-5-24, May 8, 1961 and Supplement No. 1, Kay 12, 1961.

156.

W. C . Ulrich, Overall Heat Transfer Coefficient f o r Treated Water Cooler, Memo t o S. J. B a l l (April 4, 1963)

157.

S . J. B a l l , Analysis of MSRF, Cooling Water Temperature Control, Memo t o R. L. Moore (May 2, 1963).

158.

Closed Cycle Pressure Drop, MSRE Water Systeq, ORNL P & E Division Design F i l e , Sept. 22, 1961.

159

Cooling Tower Load, MSRE Water System, ORNL P & E Division, (No d a t e ) .

160.

J. C . Moyers, Requirements f o r MSRE Valves and Flanges, L e t t e r t o L. F. Parsley (April 19, 1961).

161.

L. F

. Parsley,

MSRF, Simultaneous S a l t and Water S p i l l Accidents,

ORNL MSR-61-120 (Sept. 28, 1961). 162.

A. N. Smith, Secondary Containment f o r t h e Off-Gas Lines, ORNL MSR-61-110 (Aug. 30, 1961).

163.

L. F. Parsley, Theoretical Analysis of Certain Penetration Regions of t h e MSRE Containment Vessel, ORNL MSR 61-96 (Aug. 10, 1961).

164.

L. F. Parsley, MSRF, Containment Vessel S t r e s s Studies, ORNL MSR-62-15 (Feb. 2, 1962).

References

, Cont d

525

165.

L. F. Parsley, Design of Pressure-Suppression System f o r t h e MSRF:, Memo t o R. B. Briggs (Oct. 17, 1961).

166.

R . B. Briggs, MSRF: Pressure-Suppression System, ORNL MSR-61-135 (Nov. 15, 1961).

167.

F. R. Bruce, ORNL Radiation:isnd Safety Control Manual, June 1, 1961.

168.

H. C

. Claiborne, Review of t h e MSRE Biological Shielding, ORNL

MSR-63-17 (May 13, 1963). 169.

D. W. Vroom, MSRE O f f - G a s Line and Charcoal Bed Shielding Requirements During Operation, ORNL CF-61-10-57 (Octo 23, 1961).

170.

D. W. Vroom, Preliminary MSRE Gamma Ray Source and Biological Shielding Survey, ORNL (3-61-4-97 (April 28, 1961).

171.

A. N. Smith, Shielding of O f f - G a s Lines, ORNL MSR-61-125 (oct. 29, 1961).

172.

Allis-Chalmers Co. I n s t r u c t i o n Manual and P a r t s Catalog, Buda Division, Model DC SG-300-A3E Generator, Allis-Chalmers hCSG-2505 Diesel Engine, f o r Union Carbide Nuclear Co., Contract No. W8X-18089.

173.

E l e c t r i c a l Storage Battery Company, Exide I n d u s t r i a l Division, I n s t r u c t i o n Manual, I n s t a l l i n g and Operating Exide Batteries, Form 4676, 6th ed.

174.

E l e c t r i c a l Products Company, I n s t r u c t i o n Manual f o r I n s t a l l a t i o n Operation and Maintenance of Diverter-Pole Motor-Generators, SM-1050 (Feb. 1, 1950).

175.

Reliance E l e c t r i c and Engineering Company, I n s t r u c t i o n Book, 25O-v, 25-kva, Motor-Generator Set, Book No. 819541 (Feb., 1962).

176.

T. E. Northup, MSRE Vapor Condensing System Memo t o R. G. Affel, May 28, 1964.

rrj i

- P a r a l l e l Rupture Discs,

526

ABBREllIATIolJs The following abbreviations have been used i n the

Description of the Reactor Design, Part I, ORML-TM+8: aternatzng c&ent h e r i c a n Institute of * Electrical Engineers

AIm

8;Blp

American society of Mechanical Engineers

LbsME

aSymetriCd. auxiliary B r i n e l l hardness number

brake horsepower B r i t i s h the& Unit Centigrade, degrees cubic centimeter

centimeter

=ym

atax Bhn bhP BtU OC

constant, v e v e (flow coefficient) cv dimeter dim direct current De distr distribution draving east electramotice force elevation Fahrenheit, degrees

Dwg

feet per second feet

t3-w

gal

E emf elev OF

* Ifow the I n s t i t h e of Electrical and Electronic Ehgineers, I=.

k L d

527

gallons per minute

glFrm

he&erx-: horsepower hour inches inside diameter instrument interugt current iron pipe size kilogram leilowatt kilovolt kilovolt-amphere liter

htr

hla hr in.

ID instr IC

IPS

u kw kv

kva 1

phase pounds pounds, force

maxirmrm

mix

mills, 1,Ooo circular

mall

ldDiram roentgen equivallentman, x 106 Molten S a t Reactor Eq?eriment

min MSRE

megawatt

HatlonaJ. Electrical Manuf’ktupers Association

“4

nominal pipe s i z e

HBS n

neutrons north ndber Oak Ridge Mational Laboratory

lbs

lbsf

mrem

H NO.

O m ag

OD ,i ,

I-W L

PP Pa

528

parts per million pounds per in.2, absolute poundd~per in.2, gage power factor radiation, absorbed dose reference revolutions per minute reactivity reactivity change receptacle roentgen roentgen equivalent man roan root mean square

schedule SeCOIld

south stainless steel standard cubic feet per minute standard temperature and pressure switch switchgear Tennessee V a l l e y Authority thennocouple transfer traasf omer unified national coarse tkread universal gas constant volt watt west

mean psla Psi43

PF rad

ref rpm

k &

recept r rem

Rm RMS sched sec S

ss SCfb

SlT 8w

TVA

TC XFer

XFmr UNC R V W

529

4vI Note:

AB ABC

(AC) AC ACB

AD-1 AD-2

AD-3 AD BH

c -1 c-2 c -3 CAP

CBC

cc CCC CCP

CDC CDT

cc COP

AND TIO ON ~ I A T I O X S

Several changes were made i n the abbreviations 88 the MSRE design progressed. Since the reference literature and drawings e e use of sane of the old notations, all of the abbreviations hare +beenincluded i n t h i s listing, but w i t h those considered 1 4 e inclosed i n parenthesis. Some duplications exist, .but h’cases the context I n w h i c h the abbreviation is used w i l l nbalee.the choice of ngs evident.

Radiator Caustic Scrubber Absorber :Cubic Contafnment ,Stack Condensate Storage Task, 1, 2 Coolant s a t Sampler Cooling Tower CW Cooling Tower Pump, 1, 2 Radiator By- pas^ Duct Esrit Air Duct f’rum Radiator CTW Cooling Tower Water and Coolant Stack CTWR Cooling Tower Water Return Air Dryer, 1, 2 (DB) Duct Blower Auxiliary Rooan Decontaaninatlon C e l l Dc Blower H o u s e DCC Drain C e l l Cooler Waste Tank Vent Blowcr DH Mesel House 3Q-Ton Crane DP Diesel Panel 10-Ton Crane DPI Mesel Panel, Switch House 3-Ton &=e D??M Diesel Panel, Atax. Control Rn. copltaiment Air panels DR C o v e r Gas Dryer, 1, 2 ChasrrcoSCl Bed, IA, Ifjj 2B Decontamination C e l l Chardoal Bed Ce (m) Drajtn T m k Condenser Coolant C e l l M”C Drain Tank Cell Cooltpnt cell Cool hergerpcy Nitrogen Station coqponent’Cooling ELectrlc Service Area Coolant Dj;.ain Cell ESC 4uLment Storage C e l l coolant D;.eein TEZIIC (E) Ea8t Tunnel cover as' [panel) F Stack Mlter, 1, 2, 3 Coolant Rang Lube O i l Fump01,2 Fuel Drain Tank, 1, 2 Coolmt PCamIp Fuel Dran Tank, 1, 2 C

(m)

530

Freeze mange (five) Fuel mush Tank Blower House F2 Preheater F2 Reactor Fuel Pump Lube O i l Pun@, 1,2 Fuel Prmrp Fuel Processing C e l l Fuel Processing S-ler Fuel Sampler Fuel Storage Cell Fuel Storage Tank Freeze Valve (Twelve) Feed Water Tank, 1, 2 GELS cooler (Cmponent Cooling System) GELS coolant ~ u m p(Ccxwned cooling Systm) 1, 2 GM o i l ~ u m p(Ca3Ilponent Cooling System) 1, 2 High Bay

Heater Control Panel H e l i u m Dryer, 1, 2 Heater Distribution Panel Treated H e l i u m Surge Tank Fresh H e l i u n S m l y Trailer H e l i u m Preheater Heater Panel (primtuy) Heat Exchanger Instrument Air Dryer, 1, 2 Inlet f i l t e r ( ~ g ~h a Area) y Leak Detector Leak Detector Lube O i l Package Liquid Waste Tagk Motor

Main Board

MB-1

W n Blowers t o Coolant Radiator Annulus Blowers t o Coolant Radiator Ducting Motor Control Center Motor Control Center, !I!VA Main Control Roan Maintenance Control Roan (Remote) Maintenance Control

m-3 m-2

MB-4 MCC MCCT

MCR (MCR) RMCR

ROCXU

Motor -Generator MG-1 250-v Motor Generator Set MG-2 48-v Motor-Generator Set MG-3 48-v Motor-Generator Set M G - ~ 25-lnra Motor-Generator Set MFC Maintenance Practice Cell Main Sung (Pump) Rooan Nuclear Panel NP OBE outside Building, East OBS Outside Building, South oc O i l Cooler, 1, 2 (m) (Operating) Main Control Rooan O i l Catch Tank, 1, 2 OCf O i l Filter, 1, 2 OF OFf Fuel Pump Overflow Tank O i l (Fill) S w l y Tank Oxygen Remval Ihzit, 1, 2 OR O i l S w l y T&, 1s 2 OT Cover Gas Preheater, 1, 2 PH PLw W-ft Elev Passage, W Side PP P i t PLrmg Pump Rooan PR Process Water (Storage) Tank R Reactor Instrument Air Receiver R-1 MG

(om

;Al

t ‘k, I

531

Instrument Air Receiver Service Air Receiver R-3 Reactor C e l l RC RCC Reactor Cell Cooler RDB Radiator Door Brake RDC Radiator Door Clutch RllM Radiator Door Drive Remote Maintenance C e l l RMC s-1 containment (O-Gas) stack sc Spare C e l l (sc) Stem Condenser Steam Dome (Drum) on ED SD SDC Stem Dame Condenser, 1, 2 Sampler-Enricher SE SER Special EquLpment Roam Stack Fan, 1, 2 SF (SFA) Stack Filter (Fan) Area Sodium Fluoride Absorbers SFA sodium Fluoride Trap SFJ! Switch House SH SOP SO2 Preheater S q R o ~ ,A, B SP Solenoid Rack SR Service Roam SR Surge Tank ST Service Tunnel ST sv Saqler-Enricher Vacuum plmrp (TC) Transfer (Spare) C e l l (Cooling) Tower Fan, 1, 2 TF Transmitter Rack (Roam) TR TRM Transmitter Roam Thermocouple Scanner TS TWC Treated Water Cooler R-2

Treated Water Pump VH Vent House VH-1 Volume Holdup Inside RC VH-2 Volume Holdup i n CBC VP vacuum Pump Vapor Condensing Tank, 1, 2 VT Waste Blower WB Waste Filter WF WOR Waste Oil Receiver, 1, 2 WP Waste Prma, Water Roam WR Liquid Waste Tank WT West Tunnel WT Waste (Tank) l’reaknent WTC C e l l , or Liquid Waste C e l l

TWP

SSM

31X

31A

31M

IIX

IIM

WIX

WIA

WIM

31X

31M

dc-

A3M

A3X

03X

O3A

03M

-- --

I X

S l

I d S d I d -- W d -- W l

-- A 1 11

I A

313

380

113

IIV

W13

WIV

31V

A33

A3V

d Z c

z BI x x

d Z

03V

I V

f U

9 I I I

Z 0

d z

0 z

Z 0

c 3 s 2

5 e

u2 K

Y id

-1

c z

Z 3

z 0 c

e VI W

4 z

WB!eA

p!aedS

-- 3M 3M VM A

VA AQSOaS!A

s 0

PUDH '*Old

S!SAIOUV

S!*!+anPuo3

A4!suoa

s!J4ael3

(IDnUDu)

ID*Jew

1-01

OJnSSOJd

uo!cD!pq

P-dS

-- 3d 3d V d d

V l

uo!4!sod

SSX

ASZ SSZ 31Z l l Z WIZ 312 A3Z 032 -- 1z sz 12 -- -- IZ -- 32 32 vz z -- 3x 3x vx x

ASX ASM SSA

03d

Un(oJ*duel

A3S

037

WIS

A31

A3d

IIS

311

31d

SSS

Wld

ASS

Wll

ASA 1lA 31A A 3 A - - I A SA 1 A -IA 3A A S 1 S S I 381 111 W I l 311 A 3 1 031 A I 11 SI 11 -- W l I1 -- 31 31 V I 1 1s -- ws 03s --- 3s 3s vs s IS 31s 31s -- -- 11 sa 11 b1 w 1 -- 31 31 v1 tl lld

031

111

A31

31d

311

317

WI8

SSd

111

SSl

318

ASd SSI

SS1

AS1

SSH

AS1

-SS3

-- -- -- -- -- -- -- -SI tll Dl -II - -31 V I I (W!O -- I I H WIH 31H A3H 0 3 H -- AH -- SH -- -- -- - -- -- 3 H V H H 113 W I J 31d A 3 3 033 -- A 3 1 3 SA 8 3 b3 W 3 I3 93 33 33 V 3 3

AS3

ASH

SS3

AS3 31V

d Z

Z 0

AS3 313 W13 313 A 3 3 033 --- 13 S 3 83 b3 W3 13 33 3 3 v3 3 3a va a i i a wia ma m a o3a - -- l a sa Ha -- wa la -Ass ssa 13 -- 33 33 v3 3 033 - - 13 s3 13 -- w 3 320 113 313 -- -sv 1v - wv -- 3v 3v vv v SSV

ASV

U n

-.--..-.__...I

~. . . .-- -

. ....

.__. . .. .."

, ,

.-.

"_.

533

PROCESS LtNES

14'\

Unclassified ORNL DWG 64-9111

PRIMARY LIQUID LINE

SECONDARY LIQUID LINE

PRIMARY GAS OR VAPOR LINE

SECONDARY GAS OR VAPOR LINE

-... --

TWO-WAY

ELECTRIC I

THREE-WAY

SOLENOID

FOUR-WAY

NORMALLY (OPERATIN(

SED ISITION)

THREE-WAY NORMALLY (OPERATIN(

ISEDWITH -VE PORT ISITION)

COMMON PORT

EXCESS-FLOWVALVE

NORMALLY (OPERATIN(

:N ISITION)

-pa-

CHECK

THROTTLIN

-RUPTURE DISC

RELIEF OR SAFETY

R INSTRUMENT LINES CONNECTION TO PROCESS

MANUALLYOPERATED

AIR OR PNEUMATIC SIGNAL LINE

, , /,

, ,

/I,

811

, , ,

I,,

.VE THROTTLING

, /

COMMON PORT

MANUALLY OPERAT ED EXTENSION HANDLE

HYDRAULIC LINE

THREE-WAY

>R OPERATED

(X) INDICA1 (ACTUA

fALVE FAILS CLOSED rMEDlUM FAILURE)

(0)INDICA1 (ACTUA

fALVE FAILS OPEN rMEDlUM FAILURE)

( X ) PLACED THREE-\ PORT FI

ONE PORT OF VALVE CLOSEDINDICATES

(ACTUA

*MEDIUM FAILURE)

/// ,//

SELF-OPERATED

d -3'

(FILLED SYSTEM 1 CAPILLARY TUBING

ELECTRICAL SIGNAL OR CONTROL LINE

-X-

xx--

(DIAPHRAGM OR BELLOWS) OPERATED

- ---------

PISTON OPERATED &;;&G's

INSTRUMENT OR PROCESS LINE JUNCTIONS OR CROSSOVERS

VALVE OPERATOR WITH POSITIONER

LINE JUNCTION VALVEOPERATOR WITH HANDWHEEL I

LINE CROSSOVER

- - - - +-- - I

Figure A.2

Symbols Used on

STRAINER

FILTER

COMMON PORT

534 SYMBOLS USED IN MSRE DRAWING IDENTIFICATION "BEB

HH Instrumentation and Control H E 4 Nuclear HE-B Process m-c Health Physic6 HH-D Services HE-Z btLscellaneous BB Reactor B B 4 cell BB-B Vessel BB-C Auxiliary BB-D StWCtUral BB-Z Miscellaneous

cc Pumps CC-A CC-B CC-C CC-D CC-Z

Fuel Coolant Auxiliary Structural Miscellaneous

SaLt

Air AuxKiliary StruCtursl Mis~ellsneOUs

EE H e a t Exchanger EE4 EE-B EE-C EE-D EE-2

fi"URLsalt Coolant Salt Auxiliary

Structural Miscellaneous

FF Salt Storage and Bandling FF-A Vessels FF-B

S-liw

and W i c h i q

FF-C Awciliw FF-D FF-Z

Structural Miscellaneous

GG Process Piping GG-A

GG-B

GG-C GG-D GG-E GG-z

JJ4 JJ-B JJ-C JJ-D JJ-E JJ-Z

Layout Tank6 and E i l t e r S

Ccqonents AUiliW StrUctWaL Mi6Cd.laIEOU8

KK B u i l d i n g and Services K K 4 AirILandling KK-B =ping KK-C R e c t r i c a l KK-D Structural

KK-E Civil KK-z Miscellaneous

DD Radiator

DD4 DD-B DD-C DD-D DD-Z

JJ G a s System

primaryLay€)ut Secondary W O U t Coqponents A~~ilit~y Stm\ctural Miscellaneous

I3l Maintenance Equipment

U4 Handling Gear U-B LL-C U-D U-E

Tools

Controls

Structural Awriliw u - 2 Miscellaneous

MM Process Heatina; P I P I 4 Pipeline Heating MM-B Cosqponent Heating MM-C Schematic Magrams MM-2 Miscellaneous ZZ Miscellaneous ZZ-A

Process

ZZ-B Services ZZ-C 22-2

Building Miscellaneous

d I

Y . \

535

LJ ORNL-TM-728

I n t e r n a l Distribution

1. R. K. Adams 2. R. G. Affel 3. L. G. Alexander 4. G. W. AUin 5 . A. H. Anderson 6. R. F, Apple 7. C. F. Baes 8. S . J. B a l l 9. S . E. Beall 10. M. Bender 11. E. S . B e t t i s 12. F. F. Blankenship 13. R. Blumberg 14. A. L. Boch 15. E. G. Bohlmann 16. C . J. Borkarski 17. H. R. Brashear 18-23. R. B. Briggs 24. G. H. Burger 25. S. Cantor 26. R. H. Chapman 27. H. C. Claiborne 28. J. A. Conlin 29. W. H. Cook 30. L. T. Corbin 31. W. B. C o t t r e l l 32. G. A. Cristy 33. J. L. Crowley 34. D. G . Davis 35. J. H. DeVan 36. G. Dirian 37. S . J . - D i t t o 38.. R. G. Donneily 39. F. A . ' D b s s 4.0. N. E. Dunwoody 41. J. R. Engel 42. E. P. Epler 43. A. P. Fraas 44. E. N. Fray 45. H. A. F r i e m 46. J. H. Frye 47. C H. Gabbard

52. 53. 54. 55. 56-65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80. 81. 82.

83. 84. 85. 86. 87.

88. 89. 90. 91. 92. 93. 94. 95. 96. 97. 98. 99. 100. 101. 102.

4 8 . M. Jf.Gaitanis

103-108.

R. B. Gallaher J. J. WiSt W . R. Grimes

109. 110. 111.

49. 50. 51.

A. G. ,Windell R. H. Gqmon S. H. Hanauer P. H. Harley P. N. Haubenreich G. M. Herbert P. G. Herndon E. C. Rise V. D. Holt P. P. Holz A. Houtzeel T. L. Hudson J. P d Jarvis R. J. Kedl So S. K i r s l i s D. J. Knowles A. I. Krakoviak J. W. Krewson C. E. Laplb J. A. Lane C. E. Larson R . B. Lindauer M. I. Lundin R. N. Lyon H. G. MacPherson C . D. Martin H. C. McCurdy W B. McDonald H . F. McDuffie C. K. McGlothlan H. J. Metz A. J. Miller W. R. Mixon R. L. Moore R. C. Olson P. Patriarca H. R . Payne A. M. Perry H. B. Piper B. E. Prince J. L. Redford M. Richardson R . C. Robertson H. C. Roller M. W . Rosenthal T. H. Row

536 112. 113. 114. 115. 116. L17. 118. 119. 120. 121. 122. 123. 124. 125. 126. 127. 128.

H. W. Savage A . W. Savolainen D. Scott J. H. Shaffer E. G. S i l v e r M. J. Skinner T. F. S l i s k i A. N. Smith P . G. S e t h I. Spiewak R . C. S t e f f y H. H. Stone H. J. S t r i p l i n g J. A. Swartout A. Taboada J. R . Tallackson R. E. Thoma

129. G. M. Tolson 130. D. B. Trauger 131. W. C. Ulrich 132. C. F. Weaver 133. B. H. Webster 134. A. M. Weinberg 135. K. W. West 136. J. C . White 137. G. D. Whitman 138. H. D. Wills 139. L. V. Wilson 140-142. Central Research Library 143-144. Y-12 Document Reference Section 145-146. Reactor Division Library 147-150. Laboratory Records Department 151. Laboratory Records, RC

il 4

External Distribution D. F. Cope, A X , OR0 154. R. W. Garrison, AEC, Washington 155. R. L. Philippone, AEC, OR0 156. H. M. Roth, AEC, OR0 157. W. L. Smalley, AEC, OR0 158. M. J. Whitman, AEC, Washington 159-173. Division of Technical Information Extension, DTIE

152-153.