- 95 Lowering t h e p r o c e s s temperature t o 450°C and u t i l i z i n g t h e same l i t h i u m - b e a r i n g s a l t (No. 2 ) reduced. c o r r o s i v e a t t a c k t o t h e lowest l e v e l s
found i n t h i s t e s t series.
These results were provided by v e s s e l No. 1 where
t h e approximate losses were 0.02 rnil/hr,
based on f l u o r i n e sparge time.
This
i s es p e c i a l l y si.gni f i c a n t since l i t h i u m - sodium- z irconiurn f l u o r i d e s a l t mix-
, t u r e s can be used i n t h e v o l a t i l i t y process a t lower o p e r a t i n g temperatures
t h a n t h e NaF-ZrF4 composite system because o f the lower l i q u i d u s l i n e of t h e li thium-beari-ng s y s t e r n .
Tes-ts Nos. 10 and
s a l t s , 31--2b-h$ mole
$J
9 at
LiF-NaF-ZrF4,
525°C used h i g h e r LiF- and ZrF4-content
wi.th and without 3-iranium, r e s p e c t i v e l y .
Vessel No. 9 showed s l i g h t l y i n c r e a s e d a t t a c k over v e s s e l s Nos. were o p e r a t e d at t h e same temperature.
4 and
*(‘ which
Metal1ographi.c examination of
v e s s e l No. 10 r e v e a l e d t h a t intergramil.ar p e n e t r a t i o n w a s p r e s e n t i n a l l phases of t h e i n t e r i o r w a l l . The A n i c k e l miniature f l u o r i n a t o r s demonstrated g e n e r a l l y lower r a t e s of corrosi.ve a t t a c k i n simulated f l u o r i n a t i o n environments when compared
t o t h e f u l l - s i z e d L n i c k e l v e s s e l s o r t h e l a t t e r ’ s A ni.cke1 i n t e r n a l components
x&-ich were exposed t o p i l o t p l a n t f l u o r i n a t i o n c o n d i t i o n s .
reasons can probably account f o r most o f t h i s dev-iatton:
The following t h r e e (1)t h e temperatures
of f l u o r j - n a t ?on g e n e r a l l y were somewhat lower i n t h e bench- s c a l e work than diiri-ng p i l o t p l a n t o p e r a t i o n s ;
( 2 ) somewhat b e t t e r c o n t r o l over thermal c y c l i n g
and o t h e r p r o c e s s c o n d i t i o n s w a s o b t a i n e d during bench-scale work; (3) t h e f e e d s a l t s used i n t h e p i l o t p l a n t w o r k were contaminated by having been used
i n previous loop s t u d i e s , the AEE, o r having been contained f o r long p e r i o d s
of time i n t h e p i l o t p l a n t type 347 s t a i n l e s s s t e e l charge melt tank.
The A n i c k e l m i n i a t u r e s a l s o demonstrated g r e a t e r r e s i s t a n c e t o
c o r r o s i v e a t t a c k d u r i n g f l u o r i n a t i o n t h a n t h e I n c o n e l v e s s e l used i n Chemical Development h o t - c e l l s t u d i e s .
C.
INOR-8 P l u o r i n a t o r s 1. T e s t Method Four IN OR-^ t e s t f l u o r l n a t i o n v e s s e l s , e a c h 1-in.-0.d.
0.065-in.-wall
and
thLckness, and of similar d e s i g n t o t h e A n i c k e l r e a c t o r s