i n s e r v i c e , b u t t h e anoma1.y o f t h e s i t u a t i o n i s t h a t maximin w a l l - t h i c k n e s s l o s s e s occurred i.n t h e Inconel v e s s e l a t t h e v a p o r - s a l t i n t e r f a c e and a t -that p o i n t no evi-dence o f i n t e r g r a n u l a r a t t a c k could be found.
No e x p l a n a t i o n can be given f o r t h e i n t e r i o r w a l l i n t e r f a c e anomaly d e s c r i b e d nor can one be given f o r t h e heavy e x t e r i o r i n t e r g r a n u l a r
a t t a c k which has l o c a l i z e d i n a c o o l e r r e g i o n of t h i s Inconel f l u o r i n a t o r ( s e e ~ i g 34). .
B, A N i c k e l P l u o r i n a t o r s I
1.
T e s t Method. In a d d i t i o n t o t h e Inconel f l u o r i n a t o r r e p o r t e d lipon i n
S e c t i o n ITPA, t e n A n i c k e l m i n i a t u r e f l u o r i n a t i o n ?-essels, each 1 - i n . and 0.035-in.-wall.
-0.d.
ti?i.ck.ness, have been o p e r a t e d by the V o l a t i l i - t y Studi.es
Gi*oup, Chemical Development
Sec-Lion A,
i n o r d e r t o compare f l u o r i n a t o r cor-
r o s i o n u s i n g d i f f e r e n t process f l o w s h e e t s .
Figure 35 shows t h e uniJLs i n t e s - t
p o s i t i o n , while Table X I I T i s a summary of t h e imposed t e s t cofiditions. The v e s s e l s , j.n a l l cases, were charged w i t h 75 g of f l u o y i d e s a l t t h a t had been ground and cl-assified t o
-8 +20 mesh.
The v e s s e l s were
t h e n p l a c e d i n s p l i t ; tube-type Furnaces and.brought t o t h e s p e c i f i e d temperat u r e under a n i t r o g e n purge o f 0.05 l.iters/min.
A-l; temperature, t h e n i t r o g e n
w a s bypassed and f l u o r i n e was allowed t o bubble thiwugh t h e s a l t a t t h e same flow r a t e .
I n iliose c a s e s where urani.um w a s added t o t h e m e l t , 0.50 g
incret-nents of UF
added a t interva1.s o f 1 h r o r more.
4 were
As shown, some
r e a c t o r s were p l a c e d i n s e r i e s b o t h f o r conveni.ence and t o mini-mize t h e f l u o r i n e consumption.
50
The -total. e k r n e n t a l f l u o r i n e exposure i n each case
h r at, a rate of 0.05 I.iters/min.
a c t o r s Nos. 5,
6, and
Du-t.ing t h e s e 50-hr exposures on t e s t re-
10, twenty-five UF
were made.
7.7a-13
4 additions
and Uli'
6 volati.lizati.ons
I n a l l . t e s t s , t h e s a l t s were kept molten f o r over 200 h r while under a n i t r o g e n purge.
This w a s done t o f a c i l i t a t e t h e t e s t procedure, t h a t
i s , a v o i d r e m e l t i n g s a l t s f o r t h e next f l u o r i n e t e s t period. .Figures 36 and 37 i l l u s t r a t e the c o r r o s i o n r e s u l t s o b t a i n e d by rni.crometer measurements and