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ORNL-TM-4 698 UC-76 - M o l t e n Salt Reactor Technology
.
C o n t r a c t No. W-7405-eny-26
CHEMICAL TECHNOLOGY DIVISION
ENGINEERING DEVELOPL/IENT STUDIES FOR MOLTEN-SALT BREEDER REACTOR PR.OCESSING NO. 18
J . R. Hightower
, Jr .
MARCH 1975
NOTICE This d o c u m e n t contains i n f o r m a t i o n of
a preliminary nature
and was prepared primarily f o r Internal use a t the Oak Ridge National
L a b o r a t o r y . i t is subject t o revision or correction and thoreiore does n o t represent a final report.
OAK RIDGE LJAT'TONAL TABOKATOKY Oak Ridye, Tennessee 37830
operated by
U N I O N CliKBIDl32 CORPORATIOLIJ
"'':YRGY
f o r the RT SEAECH A N 3 DEVL.:LOPYC:NT ADl.IINISTP4TION
3 445b 0550514 7
ii
R e p o r t s p r e v i o u s l y i s s u e d i n this s e r i e s are a s follows: OWL-TM- 3053
P e r i o d ending December 1968
ORNL-TM- 3137
P e r i o d ending March 1 9 6 9
ORNL-TM-3138
P e r i o d ending June 1969
ORNL-TM-3139
P e r i o d e n d i n g September 1969
OWL-TM-3140
P e r i o d ending December 1969
Oâ‚ŹU\IL-TM-3141
P e r i o d ending March 1 9 7 0
OKNL-TM-3257
P e r i o d ending June 1 9 7 0
OWL-TM- 3258
P e r i o d e n d i n g Septemher 1970
ORNL-TM-3259
P e r i o d ending December 1 9 7 0
OHNL-TM-3 352
P e r i o d ending March 1 9 7 1
iii
CONTENTS
............................ 1. INTRODUCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . SALT-PETAL CONTACTOR DEVELOPMENT . . . . . . . . . . . . . . . . .
Page
SUMMARIES
2.1 2.2
......................... Experimental S t u d i e s Using Water-Mercury Systems . . . . . . Background
2.2.1 2.2.2
3
4
.
.
1
1 2
4
............... 4 ....................... 5 C o r r e l a t i o n s w i t h MTE-3 Data . . . . . . . . . 10
Experimental p r o c e d u r e s Results
2.3
Comparison of
2.4
Experimental S t u d i e s i n t h e Salt-Bismuth Flow-thro1.igh Facility
..........................
2.4.1 2.4.2 2.4.3
v
10
. . . . . . . . . . . . . . . . 13 . . . . . . . . . . . . . . . . 13 . . . . . . . . . . . . . . . . . 18 f o r MSBR P r o c e s s i n g P l a n t . . . . . . 2 0
Experimental equipment Mathematical a n a l y s i s : Experimental r e s u l t s
2.5
C o n t a c t o r A r e a Required
2.6
Conclusions
.........................
DEVELOPMENT OF THE METAL TRANSFER PROCESS : ENGINEERING-SCALE EXPER.IMENTS 3.1
Examination of M'FE-3
3.2
S t a t u s of Experiment
CONTIPJUATION OF
.................. Equipment and Materials . . . . . . . . I4TE.3B . . . . . . . . . . . . . . . . .
22
23 26
32
CONTINUOUS FLUORINATOR DEVELOPMENT
. . . . . . . . . . . . . . . .
37
4.1
Autoresistance Ileating T e s t s
................
37
4.2
D i s t r i b u t i o n of Current D e n s i t i e s i n t h e A u t o r e s i s t a n c e H e a t i n g Equipment
...................... 5 . REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . .
39
44
V
SUMMARIES SALT- METAL CONT AC TOR DEVELOPME IV T
A water-mercury
system was used t o study t h e e f f e c t of ycometric
v a r i a t i o n s on m a s s t r a n s f e r r a t e s i n r e c t a n g u l a r c o n t a c t o r s s irriilar t o t h o s e proposed f o r t h e MSBR f u e l r e p r o c e s s i n q scheme.
Since I n a s s t r a n s -
f e r r a t e s were n o t a c c u r a t e l y p r e d i c t ( - d by the T>ewis c o r r e l a t i o n correlations w e r e invest iyated.
,
other
T h e f o l l o w i n q c o r r e l a t i o n w a s found t o
f i t t h e experimental r e s u l t s :
60 k b v
=
1
0.2058 (Re
(0.6
q2 + r' 1
M a s s t r a n s f e r r a t e s a r e b e i n g measured in a fluoride salt--bismuth
contactor.
m i l d steel c o n t a c t o r has been instalLed i n t h e
A 6-in.-diiim
flaw-through r e d u c t i v e e x t r a c t i o n f a c i l i t y for t h i s p u r p o s e .
Experimen-
t a l r e s u l t s from t h e s e r u n s i n d i c a t e t h a t the m a s s t r a n s f e r - rates i n t.hr? s a l t - b i s m u t h system fall between t h e L e w i s c o r r e l a t i o n and t h e modified c o r r e l a t i o n g i v e n above
e
DEVELOPPMNT OF THE METAL TRANSFER PRQCESS : CONTINUATION OF ENGINEERI NG-SCALiE EXP ERTPIIF,N'1' S
Four e n g i n e e r i n g - s c a l e
e x p e r i m e n t s (Pll'E-l,
-2
-ZA, and - 3 ) t o study
t h e s t e p s i n t h e m e t a l t r a n s f e r p r o c e s s were completed p r i o r t o t.he t e r -
i n i n a t i o n of t h e ?4c)lten-Salt Reactor Program e a r l y in 1 9 7 3 . e x p e r i m e n t , MTE-3,
The last:
used s a l t and bismuth flow r a t e s t h a t were 1% of the
e s t i m a t e d flow r a t e s r e q u i r e d f o r p r o c e s s i n g a 1 O O O - M w ( e ) r e a c t o r .
We
p l a n t o c o n t i n u e t h e s e s t u d i e s i n a. new e x p e r i m e n t , d e s i g n a t e d a s !?T'E:-~;B ( i d e n t i c a l t o MTE-3).
The carbon steel vessels used i n experiment MTE-3 a r e b e i n g r e p l a c e d w i t h new v e s s e l s . be used.
F r e s h c a r r i e r s a l t , b i s m u t h , and l i t h i u m c h l o r i d e will
vi
R e s u l t s of measurements of t h e mass t r a n s f e r c o e f f i c i e n t s f o r radium, europium , lanthanum I and neodymium, o b t a i n e d d u r i n g o p e r a t i o n of e x p e r i -
ment: MTE-3, i n d i c a t e d t h a t many of t h e c o e f f i c i e n t s were lower t h a n p r e d i c t e d by l i t e r a t u r e c o r r e l a t i o n s .
The r e a s o n for t h i s i s p r e s e n t l y n o t
known; c o n s e q u e n t l y , a d d i t i o n a l s t u d i e s a r e r e q u i r e d i.n o r d e r t o o b t a i n d a t a n e c e s s a r y â‚Ź o r d e t e r m i n i n g t h e s i z e and t y p e o f equipment r e q u i r e d f o r removal of t h e r a r e - e a r t h
f i s s i o n p r o d u c t s from m o l t e n - s a l t r c a c t o r
fuel. Examination o f t h e MTE-3 carbon s t e e l v e s s e l s indicaLed t h a t no s e r i o u s c o r r o s i o n had o c c u r r e d on t h e i n s i d e s u r f a c e s of t h e v e s s e l s exposed t o s a l t and bismuth d u r i n g 1 y e a r of o p e r a t i o n at: 65OOC ( a l t h o u g h t h e o x i d a t i o n - r e s i s t a n t c o a t i n g on t h e o u t s i d e s u r f a c e of t h e v e s s e l f a i l e d t o comp1.e-tely p r o t e c t t h e carbon s t e e l . ) .
Photomicrographs of t h e
bismuth p h a s e s j-ndicate t h a t t h e s u r f a c e s i.n c o n t a c t w i t h t h e sa1t.s are enriched. i n thorium and i r o n . CONTINUOUS FL,UORINATOR DEVELOPMENT
A u t o r e s i s t a n c e h e a t i n g t e s t s have been c o n t i n u e d i n t h e f l u o r i n a t o r mock-up u s i n g I,i.F-ReF -ThF 2
4
(72-16-12
mole % ) s a l t .
r e t u r n e d t o o p e r a t i n g c o n d i t i o n I and f i v e e x p e r i m e n t s
The equipment was VJWC
run.
A1:t:hough
c o r r e c t s t e a d y - s t a t e o p e r a t i o n w a s n o t a c h i e v e d , t h e r e s u l t s were encouraging. A two-di.mensiona1 e l e c t r i c a l a n a l o g w a s c o n s t r u c t e d t o s t u d y c u r r e n t
flow t h r o u g h t h e e l e c t r o d e sidearm and o t h e r c r i t i c a l a r e a s of t h e t e s t vessel.
The model used c o n s t a n t - r e s i s t a n c e p a p e r c u t i n t h e shape of
t h e sidearm.
An e l e c t r i c f i e l d w a s produced between i s o p o t e n t i a l l i n e s
of c o n d u c t i v e s i l v e r p a i n t connected e l e c t r i c a l l y t o a c o n s t a n t - v o l t a g e source.
The r e s u l t i n g f l u x l i n e s were measured u s i n g a high-impedance
voltmeter.
These s t u d i e s i n d i c a t e t h a t no r e g i o n s of abnormally h i g h
c u r r e n t d e n s i t y e x i s t e d i n t h e f i r s t n i n e r u n s with t h e p r e s e n t a u t o r e s i s t a n c e h e a t i n g equipment.
L o c a l i z e d h e a t i n g had p r e v i o u s l y been t h e
s u s p e c t e d c a u s e â‚Ź o r t h e f a i l u r e t o a c h i e v e proper o p e r a t i o n of khis equipment.
1. A mo ten-sa
INTRODUCTION
t breeder r e a c t o r
(MSBR) w i l l be f u e l e d w i t h a molten
f l u o r i d e m i x t u r e t h a t w i l l c i r c u l a t e through t h e b l a n k e t and c o r e r e g i o n s o f t h e r e a c t o r and t h r o u g h t h e primary h e a t exchangers. p r o c e s s i n g methods f o r u s e i n a close-coupled
We a r e developing
f a c i l i t y f o r removing f i s -
s i o n p r o d u c t s , c o r r o s i o n p r o d u c t s , and f i s s i l e m a t e r i a l s from t h e molten f l u o r i d e mixture. I n January 1973, t h e Molten S a l t Reactor rupted f o r about a y e a r ,
(MSR) Program was i n t e r -
The program w a s r e i n s t a t e d a t 01WL a g a i n i n
January 1 9 7 4 , and t h e s t u d y of s e v e r a l o p e r a t i o n s a s s o c i a t e d w i t h MSBR p r o c e s s i n g w a s resumed.
The remaining p a r t s of t h i s r e p o r t d i s c u s s :
(1) development o f m e c h a n i c a l l y - a g i t a t e d tactors ,
salt-metal
con-
(2)
examination of t h e vessels i n which m e t a l t r a n s f e r experiment MTE-3 was c a r r i e d o u t , and
(3)
e x p e r i m e n t s of a u t o r e s i s t a n c e h e a t i n g o f molten s a l t s conducted i n a mock-up of a f r o z e n w a l l f l u o r i n a t o r .
T h i s work w a s c a r r i e d o u t i n t h e Chemical Technology Divisi.on d u r i n g t h e p e r i o d J a n u a r y through June 1 9 7 4 .
2.
SALT-METAL CONTACTOR DEVELOPMENT J. A. Klein
A critical step i n the
proposed MSBR p r o c e s s i n g scheme i s t h e e x t r d c -
t i o n of r a r e e a r t h s from t h e f l u o r i d e f u e l c a r r i e r s a l t t o a n intermed i a t e bismuth s t r e a m .
One p o s s i b l e approach would b e t o u s e a mechanically-
a g i t a t e d n o n d i s p e r s i n g c o n t a c t o r i n which bismuth and f l u o r i d e s a l t p h a s e s a r e a g i t a t e d i n o r d e r t o f a c i l i t a t e t h e m a s s t r a n s f e r of r a r e e a r t h s across the salt-bismuth i n t e r f a c e . During t h e p e r i o d covered by t h i s r e p o r t we have c o r r e l a t e d m a s s t r a n s f e r c o e f f i c i e n t s which were measured i n a water-mercury
system w i t h
those which were c o l l e c t e d from t h e open l i t e r a t u r e f o r aqueous-organic
systems.
We have completed f o u r experiments i n which m a s s t r a n s f e r
2
coefficients
j
n a â‚Ź l u o r i d e sal t-bismuth system were measured.
T h i s work
i s discussed i n t h e following s e c t i o n s . 2 . 1 Back.groi.ind
Lewis'
i n v e s t i g a t e d mass t r a n s f e r r a t e s i n m e c h a n i c a l l y - a g i t a t e d
n o n d i s p e r s i n g c o n t a c t o r s I a l l of t h e same size, u s i n g s e v e r a l aqueouso r g a n i c systems.
He f i t t e d h i s results w i t h t h e fo11.owiny e m p i r i c a l
equation:
where
2
NL p , r,
Re
=
Reynolds nunher =
N
=
s t i r r e r speed
k
=
m a s s t r a n s f e r c o e f f i c i e n t , cm/scc,
p
:=
d e n s i t y = g/cm
Q
=
viscosi-ty = g/cm*sec,
v
=
kinematic v i s c o s i t y = q / p
=
phase b e i n g c o n s i d e r e d .
1,2
rps,
3
,
For t h e c a s e i n which N reduced t o t h e form
1
= N
2
=
arid L
2
c m / s e c , and
1
=
L2, t h e above eqiiati-on can b e
F o r Lewis' work, where t h e densities o f t h e v a r i o u s phase:; v a r i e d from
0 . 8 t o 1 . 2 9/cm3 but t h e s t i r r e r l e n g t h w a s k e p t c o n s t a n t , t h i s c o r r e l a -
t i o n e f f e c t i - v e l - y u s e s only t h e Reynolds number o f t h e p h a s e being considcrcd.
3
r4cM;inmey
2
c o r . r e l a t e d h i s own d a t a w i t h L e w i s ' s r e s u l t s by t h e f o l -
lowiily e x p r e s s i o n , which i s similar to t h a t u s e d by Lewi.3 b u t incl-udes t h e Schmidt number:
where
Sc
=
Schmidt number = n / p D ,
D
=
d i f f u s i o n cmefficientl == cm /set.
and 2
Note t h a t the dependence on t h e Schmidt number i s f a i r l y weak.
'This equa-
t i r j n can he r e d w e d t.0:
613 k.1,
v
1
-0.37
0.102 (L)( R e l )
1
Again, t h e IZeynolds number o f t h e phase b e i n g c o n s i d e r e d .i.s t h e tlnmin a n t f a c t o r , a l t h o u g h i t i s raised t o a d i f f e r e n t power from t h a t used by ( i . e . , 0 . 9 r a t h e r than 1 . 6 5 ) .
Lewis
Maytiirs3 develvpc:d a s l i g h t l y more invo1vc.d
correla.t:icn of tile
f o l l o w i n q form:
This e q u a t i o n r e d u c e s t o : SO klL
c I c x -
V
1
--
0.1895 (Rel)
($)
1.4
(0.6
-t
):
-2.4
(scl)
0.5
T h i s c o r r e l a h i o n i n d i c a t e s t h a t t h e v i s c o s i t y and d e n s i t y p h a s e af F e c t t h e mass t r a n s f e r c o e f f i c i e n t . on data c o v e r i n g a l i m i t e d r a n g e of d e n s i t i c s
CJ
. 1-
(6)
each
This c o r r e l a t i o n i s b a s d 3
( 0 . 8 t o 1 . 2 g/cm )
.
4
All of t h e above e q u a t i o n s c o r r e l a t e t h e Large amount of aqueouso r g a n i c d a t a v e r y w e l l ; t h e Mayers and McManamey c o r r e l a t i o n s p r o v i d e a s l i g h t l y b e t t e r fit khan t h e Lewis c o r r e l a t i o n .
Xowever I i n a l l c a s e s ,
N , ql, and q 2 w e r e t h e o n l y p a r a m e t e r s v a r i e d t o any s i g n i f i c a n t e x t e n t .
The o t h e r v a r i a b l e s were e i t h e r h e l d c o n s t a n t o r were v a r i e d a v e r v e r y s m a l l ranges.
2.2
Experimental S t u d i e s Using Water-Mercury Systems
Previous r e p o r t s 4 ’
have shown that. a water-mercury
contactor using
the reaction Pb
2+
[H201
C
Zn[Hgl
j .
zn[IfgI
f
2+
Zn
[1120]
i s s u i t a b l e f o r st:udy:ing m a s s t r a n s f e r r a t e s i n t h i s system.
These stud-
i e s have i n d i c a t e d t h a t , a l t h o u g h r e s u l t s were g e n e r a l l y s i m i l a r t o the
pred.ict:ions o f t h e L e w i s c o r r e l a t i o n , s i g n i f i c a n t d e v i a t i o n s from t h e c o r r z l a t f i o n do e x i s t .
Tn o r d e r t o r e c o n c i l e t h e s e d i s c r e p a n c i e s , we
have s t u d i e d t h e e f f e c t _ of g e o m e t r i c v a r i a t i o n s on mass t r a n s f e r r a t e s i n r e c t a n g u l a r c o n t a c t o r s s i m i l a r t o t h o s e proposed for t h e MSBR f u e l r e p r o c e s s i n g scheme.
2.2.1
Experimsntal procedures Three r e c t a n g u l a r c o n t a c t o r s were f a b r i c a t e d in t h e f o l l o w i n g s i z e s :
5-1/4 i n . x 7
iil.,
7-3/4 in. x 1.0-1/2 i n . , and l l - 5 / 8
i n . x 12-1/2
in.
The two s m a l l e r vesse1.s were c o n s t r u c t e d of P l e x i g a s , rwhile t h e l a r g e r
was c o n s t r u c t e d o f s t a i n l e s s s t e e l . A y i - t a t o r b l a d e s having d i a m e t x r s of 3 , 5 , and 7 i n . were f a b r i c a t e d . One s e t of b l a d e s had a c o n s t a n t h e i g h t of 3/4
i.11.
a n o t h e r s e t had a
c o n s t a n t b l a d e d i a m e t e r / b l a d e h e i g h t r a t i o of 4 . 0 .
A l l of t h e b l a d e s
were four-vaned s t r a i g h t p a d d l e s ; . Each c o n t a c t o r was used t o make a large nwrher of e x p e r i m e n t a l r u n s i n which t h e phase volume, b l a d e s i z e , and a g i t a t i o n r a t e s were v a r i e d . A g i t a t i o n r a t e s were l i m i t e d t o v a l u e s below t h e p o i n t a t which d i s p e r s i o n
5
of t h e p h a s e s became a p p a r e n t .
The p a d d l e s used i n t h e two p h a s e s w e r e
identical. i n s i z e . D e t a i l s o f sampling and a n a l y s i s o f d a t a are i n c l u d e d i n a p r e v i o u s report.
2.2.2
4
Results R e s u l t s o b t a i n e d u s i n g t h e 7-3/4-
by 10-1/2-in.
c o n t a c t o r and a 5000-
cm volume f o r e a c h p h a s e a r e compared w i t h t h e t h r e e c o r r e l a t i o n s i n F i g s . 1-3.
Similar r e s u l t s w e r e obtained f o r other contactor sizes.
y i v e s t h e d a t a â‚Ź o r t h e water-mercury s y s t e m .
Table 1
Phase 1 .is mercury; phase
2 i s water. Experimental mass t r a n s f e r c o e f f i c i e n t s ranged from 5 t o :30% of t h e v a l u e s p r e d i c t e d by t h e L e w i s c o r r e l a t i o n .
The slope o f t h e d a t a d e v i a t e d
s i g n i f i c a n t l y from t h a t o f t h e L e w i s c o r r e l a t i o n ; it a g r e e d v e r y c l o s e l y w i t h t h e s l o p e o f t h e McManamey c o r r e l a t i o n , a l t h o u g h e x p e r i m e n t a l v a l u e s
were o n l y 15 t o 30% o f p r e d i c t e d v a l u e s .
Thus it a p p e a r s t h a t t h e
McManamey c o r r e l a t i o n i s o n l y s l i g h t l y b e t t e r t h a n t h e L e w i s c o r r e l a t i o n . T h e s l o p e o f t h e Mayers c o r r e l a t i o n a l s o matches t h a t of t h e d a t a v e r y
w e l l b u t u n d e r p r e d i c t s e x p e r i m e n t a l r e s u l t s by 4 0 t o 50%. The r e s u l t s shown i n F i g s . 1 and 2 , as well as t h e remainder o f t h e data, i n d i c a t e t h a t t h e m a s s t r a n s f e r c o e f f i c i e n t is proportional t o t h e
s t i r r e r l e n g t h , L , r a i s e d t o a power d i f f e r e n t from t h a t a s s o c i a t e d w i t h The exponent o f L is 1 i n t h e Mayers c o r r e l a t i o n
t h e Reynolds number.
r a t h e r t h a n a p p r o x i m a t e l y 2 as i n t h e o t h e r c o r r e l a t i o n s .
T h i s change
improves t h e c o r r e l a t i o n ; however, i t a l s o s e e m s t o overcompensate t o some e x t e n t . Using t h e Mayers c o r r e l a t i o n as t h e b e s t o f t h e e x i s t i n g c o r r e l a t i o n s ,
w e added two a d d i t i o n a l t e r m s t o i n c l u d e t h e e f f e c t o f t h e d e n s i t y r a t i o o f t h e two p h a s e s (p /p
1
) and a dimension r a t i o
2
h e i g h t o f an i n d i v i d u a l p h a s e .
(L/H), where H i s t h e
The t a n k s i z e or p h a s e volume w a s shown
t o be u n i m p o r t a n t e x c e p t i n t h e manner i n which i t a f f e c t s 13.
6
F
0
3 " x +'' B L A D E S
A 5"x
1 %I"
BLADES
a
Fig. 1.
S e l e c t e d experimental results as compared w i t h the I,cwis
c o r r e l a t i - o n f o r the water-mercury system.
7
7 i3” fxIQg
CELL
5000 c c 0
COR RELATI Q
3 ” x 4 BLADES 1 ‘I
5 ” x x l ~8 L A O E S
0 7x I
SaB L A D E S
n 0 0
/’
A
EX PE R I M ETA L VA LU E S FROM W A T E R - O R G A N I C SYSTEMS
Fiq. 2 .
Selected water-mercury exper- j.nental r e s i i l t s ,as compared
w i t h t h e McManamey c o r r e l a t i o n
-
8
I
5800 c c
E X PER I MENTAL 9 A L U E S
Fig. 3 . Selected e x p e r i m e n t a l r e s u l t s as compdred with t h e Mayer c o r r e l a t i o n for the water-mercury system.
9
T a b l e 1.
Run No .
1 2 3 5 16 11 12 13 14 20 21 22 23 24 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54
(L)
Contactor size (cn)
blade size (diarn x h e i g h t )
13.3 x 17.8
7.62 x 1.90
12.70 x 3.175
19.7 x 26.7
7.62 x 1.90
60 k , L
(N)
??!lase
volume (CC)
1,200 1 ,203 1 ,200 1,200 1 ,830 1 ,800 1,800 1 ,800 1 ,800 2 ,606 2 ,630 2 ,600 2 ,600 2 ,600 1,200 1,200 1 ,800 1 ,830 2 ,600 2 ,600 2,600 3,300 3 , 000 3 ,000 5 ,000 5 ,003 5 ,030 5 ,000 7 ,030 7 , 000 7 ,000 7,000 9,000 9,000
E x p e r i n e n t a l a;il p r e d i c t e d mass t r a n s f e r r a t e s for t h e water-mercury
5.2 5.2 5.2 5.2 7.8 7.8 7.8 7.8 7.8 11.0 11.0 11.0 11.0 11.2 5.3 5.0 7.5 7.5 11.0 11.0 11.0 5.5 5.5 5.5 9.5 9.5 9.5 9.5 13.5 13.2 13.5 13.2 17.1 17.0
“1
Stirrer speed ( rprc 1
Pr e d i c t e d valuea
Expe Iimen t a 1 vaiae
55 72 98 136 53 70 99 150 183 51 73 126 183 205 29 49 29 53 29 51 61 51 77 123 50 83 123 i.81 53 78 127 185 51 82
917 1200 1634 2267 736 972 1375 2083 25 00 607 333 1499 2177 2420 1676 2906 1433 247i 1206 2121 3369 829 1252 1999 635 131 7 1525 2300 575 855 1378 2028 498 832
836 577 1457 3078 689 645 1313 2710 3956 428 517 2025 3034 3711 1849 3318 1609 3811 1017 3377 6294 476 1064 1919 756 1024 1548 2507 765 1045 956 1839 421 843
R m
&go.
55 56 73 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 66 103 101 132 133 104 105 106 107 108 109
Contac t o r size (cm)
(L! Blade size (diam x h e i y h t )
19.7 x 26.7
7.62 x 1.93 12.70 x 3.175
17.78 x 4.44
110
111 130 13i 132
29.5 x 31.8
12.70 x 3.17
system
Phase volume (cc 1
9,300 9,000 3 , 003 3,000 3 ,000 3 ,000 5 ,000 5 , 000 5 , 000 5 ,0‘30 7 ,003 7,00G 7 , 008 7 , 000 7 ,eo0 9,1300 9,000 9,000 9,003 3 , 000 3 , 000 5 ,OOC; 5 , 000 5 , 000 5 ,000 7 ,000 7 ,000 :,300 9,000 9,000 9,000 25,030 25 ,030 25 ,030
tH) Phase
depth
(cm)
i : .
0
17.0 5.5 6.0 6.0 6.0 2.5 9.5 9.5 9.5 13.5 13.5 13.5 13.5 13.5 17.0 l7.0 17.2 17.2 5.8 5.8 5.8 9.5 9.5 9.5 13.5 13.5 13.5 17.2 i7.5 17.5 26.8 26.9 26.2
?:[
60 k l L
1
v
1
Stirrer speed [rpm)
Predicted
Experimental
125 150 21 41 59 79 20 44 61 75 21 40 60 80 89 20 41 60 80 21 41 48 21 35 50 2G 35 52 22 39 47 32 51 80
1223 1467 1193 2240 3223 4316 889 1955 2510 3332 797 1517 2276 3035 3376 683 1432 2041 2721 2657 5185 6073 2128 3546 5066 1730 3028 449s 1707 3002 3617 2 92 1418 2252
1022 1234 959 1840 2521 3485 884 1681 2769 4329 869 1144 2046 3133 3534 776 1372 1853 2690 2640 5094 7350 2169 4223 6104 1440 3392 6091 2118 3314 4566 1167 1435 1881
value”
value
0 r-!
m
-3
tII1
c 0
-4
3 r(
I
N'
la
JIm -
m
0 r-! r-! 0 'u-4
0
N
a, rl
ID
\ ,--I
r-7
rl
I
u
rn
u
o
N
,---. a,
ri
a,
p: p:
u
7
r l r l
0
ID
x
rl
4
L
la
c 4-J
'a
-4
a,
5 2a, c a,
h 5 ,-. Le rl
C
a
rd
r-! \ c7 rd' v
G
0
a a
c 0
v
4 '
(1
N
a, 5 ,-.
0
IH
k
a, Q! ffl
3" ffl LJ
C
a, d
0
@ a, a,
s: 4J
a
rd cl '(I
,
a -4
a,
A
m a s:
u
G rd
a,
d
.4
o
c,
0
'
h
co
v
Nul
co
\ I
rl
-
u
u rn
I
ri'
r-!
, a la
N I
0
I1 rl
4
3
x r i 0
co
4
a c, a .a
k
aJ
fd rd
+J
a
I
0
w
2 c
ffl
0
c,
-4
Id
rl
a,
k
LI 0 U 0
w
c
0 ffl
-4
k
a
14
E
U 0 N
a,
5 k LH
a
a a,
h
c,
0 04
k
a, rn
c, G a,
-4
u
.d
w e, 0
rd
a,
d
E
-4 4
c, a
1
a,
!4
!4 0
u
a c rd
u
k
a,
w
-4
c,
c:
c,
c:
a
t.4
5
m
C
a !4 c, m rn
2
a,
E
m rl
a
m
5
a
ri LJ
a
u
C
a
c: -c, -4
3
m C 0
rd
c,
-4
a,
r i
k k 0
U
a,
5 0
w
c,
a,
E
5:
a, k
a
a,
+)
s:
I
[I)
k
a
C 4)
rd
ffl
ffl
E a,
G c,
c
0
.,-i
c,
a
a,
r-4
k k
0
c)
I
3.1
a
rl r-!
2 3
c
0
c,
-4
rd a,
rl
k k
u
0
-rl
a 0
m
-4
s
m
c,
.
a,
E
a,
i :
c,
c,
w w
u
-4
a,
c
L l r-i
.TI
a,
u
c, a
5 u-l a, d
m
0
a, c w c,
k
3
I !4
E
B
c, a, E C
E0 a,
k
a,
m
-4
.c a0 +J
IH
0
4
-4
n4
c X a,
11
ORML D W G 74-683Rl
1200 c c 5 " I~~ B L A D E S
@ 1800
+
CC
2500
ZC
b
5"X
14' B L A D E S
V
CJr
V
d 1
[
0.2058 R e i R e e l Fig. 4 . mass-transfer
I
I
I
I
I
21I
I03 [T 72 ]19 [ 0.6 -+ '
2.4
3000 c c 5"r I $ B L A D E S
5000 c c 7000cc
7000cc I
I
[SC,]-~[$]
I
0*23
I
I
l
l
[ %] 0 . 4 5 i o 4
Experimental water-mercury r e s u l t s as f i t by t h e modified
correlation.
LJ
0
-4
'(i
c u ar - 4 arE
'10
u a
a
I
C
O
N rl
O
Lnr.
D
1
m
- I d
m I
m I
N
12
I
N
c
x
, I
0
x
0
x
i d
0
x
--i
0
x
x
I?
I
0
x
I
N
x
i
o T
I
N
0
x
ri
I
N
x
0
-
N
P G"
O N
0
I
i
LO
P r
1
N
x
0 874
N
x
0 8.1
N
N
O
. 0.
N
m
0
I - i
W
w
0
N rl
N
N
D
N
N
r.
r . m m
0
i-1
,-i
O
m
0 v i
4
r-d
io
0
d
CP
0
0 N
0 m
a
m
0
ro
0
L n l n i d
0
,-! ** n
N
m
Ln
w
L1
. 0. m0.
0
0
m
0
n o o o 0 d N N m m
0
m
N
. . . . . .
r-i
. .
r l m
r i m
0
r . 4 rl
0
1
0
w
d r l
r i m
I
m 0 .-i ~.i rl
0
0
0 l - 1
0
0 0
r i d
. w.
x
m
0 0 '*
r?
0
I
v7Y
x
4 - 1
0 0 M
. 0 . m r i
0
0 0 <-I
E -.-I
7
Li
n,
w
1.3
s a l t - b i s m u t h flow-through f a c i l i t y .
T h i s experi.rnenta1 system ( F i g . 5 )
( 2 ) removal of
a l l o w s (1) p e r i o d i c c l e a n i n g of t h e feed s a l t and m e t a l ,
s u r f a c e c o n t a m i n a t i o n from t h e s a l t - m e t a l i n t e r f a c e , arid ( 3 ) v a r i a t i o n o f t h e d i s t r i b u t i o n r a t i o of t h e material o f i n t e r e s t between the s a l t ant3 the bismuth.
The new s t i r r e d - i n t e r f a c e c o n t a c t o r makes use of t h e e x i s t i n g p i p i n g , equipment, and i n s t r u m e n t a t i o n p r e s e n t i n the m i l d - s t e e l
reductive extrac-
The c o r i t a ~ t o , r which is g e o m e t r i c a l l y i d e n t i c a l t o t h a t used
t i o n system.
with the water-mercury system, c o n s i s t s o E a G i n . -di.am
v e s s e l c o n t a i n i n g four 1 - i n . - - w i c k v e r t i c a l b a f f l e s .
carbon-steel
The a q i t a t o r con-
sists of two 3-in. -diam s t i r r e r s w i t h f o u r noncanted blades.
A 3/4-in.
overflow a t the i n t e r f a c e a l l o w s for removal of i n t e r f a c i a l f i l m s , a s w e l l T h e system i s o p e r a t e d i n e s s e : i n t j . a l l y the 7-l:L employed. w i t h t h e packed columii. T h e salt and b i s -
a s -the s a l t a n d m e t a l o u t f l o w .
same rnanner- a s muth
VJaS
phases were e q u i l i - b r a t e d prior t o
,311
experirrierit.
A f t e r t h e s a l t and
m e t a l p h a s e s had been t r a n s f e r r e d t o the f e e d tanks, 97Zr W C ~ Eadded
tracers
to thc salt.
237u
W i t h this t e c h n i q u e the rates <3k which
z i r c o n i u m and uranium tracex t r a n s f e r from t h e s a l t t o t h e bismuth ~ o u l d h e measured i n a syskeni tl-1a.t w a s o t h e r w i s e at: chemical equi.librium.
?.lathematicala n a l y s i s
2.4.2
I _ -
For a f low-through,
cont:iriuously s t i r r e d contactcjr at s t e a d y - s t:ate
c o n d i t i o n s , a mass balance on t h e salt: p h a s e yields:
whe r c
3
1
=
fI.ow r a t e of salt, cm /set:,
1
=
t r a c e r c o n c e n t r a t i o n i n s a l t i n f l o w , units/ciix 3 ,
C_
=
t r a c e r coucentrat:.inn i n r:alt out E.Low, unit.:;/cm
=
r a t e of t r a n s f e r o f t r a c e r across t h e i n t e r f a c e , u t ~ i t r ; / s e c .
F (7
3
J
3
,
14
n
CONTACTOR
METAL FEED AND COLLECTION TANK
SALT FEED AND COLLECTION TANK
SALT AND METAL TREATMENT VESSEL
F i g . 5 . S a l t - m e t a l c o n t a c t o r a s i n s t a l l e d i n t h e m i l d - s t e e l reductive extraction facility.
15
Expressing the rate of transEer across the interface as the product
of an overall mass transfer coefficient and a driving force times the 12 area available for mass transfer yields: J
where l/K,
= L/ks
+
K
=
overall mass transfer coefficient based on salt phase, cm/sec,
k
=
individual mass transfer coefficient in salt phase, cm/sec,
=
individual mass transfer coefficient phase in metal, cm/sec,
=
distribution coefficient = ratio of concentration in metal
and S S
k
m
D
l/Dkm
,
phase to concentration in salt phase at equilibrium, moles/ cm3 moles/cm 3 ,
Cm A
=
tracer concentration in metal outflow, units/cm3, and
=
interfacial area, cm
2
.
Taking an overall mass balance gives: C F
11
+ C F
2 2
where C2
=:
F
=
2
= C F +C,F2r s 1
tracer concentration in metal inflow I units/cm3 , and 3
flow rate of metal, cm / s e c .
If C2 = 0, Ey. (12) can b e rearranged to give the four following relations:
C F = C F +CmF2, 1 1 s 1
16
=
+)
cS + m F
(2)
,
Cs = C 1 - Cm
cm =
F
and
1.
Combining E q s . FICL - FICs
'
(9)I
(10) and (16) yields:
KsCsA
D
which can he r e a r r a n g e d t o give:
K A
Combining Eqs.
( 9 )I
(10) and (1.5) yields: I
F2 F C = E ' C - C F + K C A - ( K C A ) - 1 1 1 1 m 2 s 1 sin F1 which i s rearranged t o give: K A
C o m b i n i n g Eqs. (9), (lo), and
(14)y i e l d s :
(F),
which i s a r r a n g e d to g i v e :
Cm/C
s
==
K A S
Rearranging E q s .
(22)
(18), (201, and ( 2 2 ) gives t h r e e e x p r e s s i o n s â&#x201A;Źor t h e
o v e r a l l inass t r a n s f e r c o e f f i c i e n t i n terms o f the measureti q u a n t i t i e s
C _ , Cm, F1, 3
F2/ D,
and A:
c 1'
(23)
(24)
(25)
The above equati.ons can t h e n h e used t o c a l c u l a t e mass t r a n s f e r coeff i c i e n t s from e x p e r i m e n t a l r e s u l t s (i.e .
,
t h e r a t i o of t r a c e r c o n c e n t r a -
t i o n s i n any t w o of the s a l t o r bismuth flows). Approximately l 0 - l i t e r volumes of s a l t and bismut.11 were a v a i l a b l e , a l l o w i n g f l o w r a t e s up t o 2 0 0 cc/min.
Experimental v a l u e s o f D, the
d i s t r i b u t i o n c o e f f i c i e n t for t h e m a t e r i a l o f i n t e r e s t ,
~ ~ \ 7 . i l . l vary .
som,>what;
however, if D i s rrlade l a r g e enough, Eqs. ( 2 3 ) , ( 2 4 ) , sild ( 2 5 ) reduce to:
18
(26)
Ks
--
F
2 ___
A
â&#x20AC;&#x2DC;m -
â&#x20AC;&#x2DC;s
-
Uncertainties in the distribution coefficient: do not af feet the accuracy of the overall mass transfer coefficient.
However, when D is very large,
the overall mass transfer coefficient is essentially the individual salt-
phase coefficient since resistance to mass transfer in the metal phase is negligible in comparison.
This is seen by allowing D to assume largc
values in Eq. (11). 2.4.3
Experimental results I
Four runs have been completed to date.
All runs were performed in a
similar manner except as discussed below. While the fluoride salt and hismuth are in contact in TS, the treatment vessel, a sufficient quantity of beryllium is electrolytically added to the salt to give any desired uranium distribution coefficient (Du). Since it is impossible to completely exclude oxidants, berylli.um
needs to be added periodically in order to mai.ntain a relatively high distribution coefficient.
Periodic transfers of salt and bismuth through-
out the system are also performed to maintain the system at equilibrium.
19 P r i o r t o a r u n , t h e s a l t and bismuth p h a s e s w e r e s e p a r a t e d by p r e s s u r i z i n g T 5 and t r a n s f e r r i n g s a l t t o T 3 and bismuth t o T1.
Approximately
7 m C i of 9 7 ~ r - 9 7 ~and b 50 t o 1 0 0 m C i of 237U
s o l v e i n t h e s a l t p h a s e f o r about: 2 h r .
0 were t h e n a l l o w e d t o d i s 3 8 236u A c t i v i t i e s of t h e 95Zr and I
which w e r e a l s o p r e s e n t , were n e g l i g i b l e . S a l t and bismuth streams w e r e p a s s e d t h r o u g h t h e c o n t a c t o r v e s s e l by c o n t r o l l e d p r e s s u r i z a t i o n of b o t h T1 and 77.3.
a t a p p r o x i m a t e l y 59OoC f o r e a c h r u n .
The c o n t a c t o r w a s m a i n t a i n e d
Both p h a s e s e x i t t h r o u g h a common
o v e r f l o w l i n e , s e p a r a t e , and r e t u r n t o t a n k s T 2 and T 4 .
P e r i o d i c sampl.ing
of b o t h e x i t streams w a s accomplished by means of f l o w i n g s t r e a m s a m p l e r s i n s t a l l e d i n t h e e x i t l i n e s from t h e c o n t a c t o r . Samples t a k e n were f i r s t c o u n t e d â&#x201A;Ź o r 237U d i s s o l v e d , and counted a g a i n f o r 237U
a v e r y low l e v e l ) .
and 9 7 Z r ,
then pulverized,
(at t h i s point, " 2 ,
had decayed t o
Countiny twice w a s done i n order t o c o r r e c t â&#x201A;Źor t h e
s e l f - a b s o r p t i o n i n t h e s o l i d s a l t o r bismuth samples of t h e 207.95-kev 6237U from . No s i m i l a r c o r r e c t i o n f o r t h e s e l f - a b s o r p t i o n o f t h e 97Zr-97Nb (743.37 k e V and 658.18 kelr
@-,r e s p e c t i v e l y )
of t h e s h o r t e r h a l f - l i f e .
A complete w e t a n a l y s i s w a s a l s o r u n on each
sample.
a c t i v i t y c o u l d be done b e c a u s e
Mass t r a n s f e r r a t e s c o u l d t h e n b e c a l c u l a t e d from t h e r a t i o s of
t r a c e r c o n c e n t r a t i o n s as d i s c u s s e d p r e v i o u s l y .
Run TSMC-1 w a s mainly a p r e l i m i n a r y experiment d e s i g n e d t o t e s t t h e procedure.
I n t h i s r u n , t h e s a l t and bismuth flows w e r e a p p r o x i m a t e l y
2 0 0 cc/min and t h e s t i r r e r r a t e w a s 1 2 3 rpm.
Unfortunately, the d i s t r i -
b u t i o n c o e f f i c i e n t w a s t o o low t o e f f e c t any s i g n i f i c a n t m a s s t r a n s f e r ; t h u s mass t r a n s f e r r a t e s c o u l d riot be a c c u r a t e l y d e t e r m i n e d Run TSMC-2 w a s performed w i t h o u t d i f f i c u l t y .
flow r a t e s w e r e 228 and 1 9 7 cc/min, r e s p e c t i v e l y .
I
The s a l t and bismuth The d i s t r i b u t i o n c o e f -
E i c i e n t f o r t h i s run w a s d e t e r m i n e d t o b e a p p r o x i m a t e l y 1 . 5 , which w a s Lower t h a n d e s i r e d b u t h i g h enough t o g i v e meaningful r e s u l k s . A bismuth l i n e f a i l u r e o c c u r r e d immediately p r e c e d i n q r u n TSMC-3.
During t h e r e s u l t i n g d e l a y f o r r e p a i r s , t h e 237U
t r a c e r c o u l d be u s e d .
97
Zr decayed and only t h e
The remainder of t h e r u n went smoothly.
s a l t and bismuth flow r a t e s were 166 and 1 7 3 cc/min,
s t i r r e r r a t e w a s 162 rpm.
A h i g h Du
The
respectively; the
(> 4 0 ) w a s maintained
for t h i s r u n .
20
I n run TSMC-4,
flow r a t e s of 1 7 0 and 1 4 4 cc/min were SP-L f o r t h e
s a l t and bismuth flows; a s t i r r e r r a t e o f 205 rpm w a s m a i n t a i n e d .
Both
d i s t r i b u t i o n c o e f f i c i e n t s a s determined from samples t a k e n before, a f t . e r I and duri-ng t h e run were g r e a t e r t h a n 200. l a r g e t h a t Eqs.
(26-28) a r e va1j.d. ]
[ T h i s v a l u e i s suEficient1.y
Large d i s t r i b u t i o n c o e f f i c i e n t s c a r -
n o t be determined p r e c i s e l y due t o t h e i n a b i l i t y t o determiile v e r y s m a l l . amounts of uranium iri t h e s a l t p h a s e .
N o s i g n i f i c a n t problems were
e n c o u n t e r e d duri.ncj t h i s r u n .
R e s u l t s f o r t h e s e f o u r r u n s a r e shown i n Table 3 . o u s l y , r e s u l t s from rim TSMC-1 a r e n o t meaningful. f o r d e t e r m i n i n g t h e mass t r a n s f e r r a t e s
[Eqs. ( 2 6 )
A s noted p r e v i -
The t h r e e e q u a t i o n s
(27) and (28)] were
used t o c a l c u l a t e v a l u e s â&#x201A;Źor t h e mass t r a n s f e r c o e f f i c i e n t
.
C o n t a c t o r Area Required f o r PISEX P r o c e s s i n g Plant
2.5
An e s t i m a t e of t h e a r e a r e q u i r e d f o r a o n e - s t a g e c o n t a c t o r f o r
removing r a r e e a r t h s from t h e f u e l s a l t can be made by u s i n g t h e mass t r a n s f e r c o e f f i c i e n t s measured i n t h e salt,--bismu'ih flow-through faci.1.i.t:y. The f l o w s h e e t assumes a t o t a l r e a c t o r fuel. s a l t volume of 4 7 , 5 0 0 l i t e r s , w i t h a s a l t flow of 55 c c / s e c ; t h i s wou1.d y i v e a 10-day removal time f o r t h e salt. time (16.6 d a y s ) .
O f t-he r a r e e a r t h s , cerium h a s t h e s h o r t e s t removal
T h e r e f o r e , a p p r o x i m a t e l y a 60% e f f i c i e n c y i s needed
f o r t h e proposed s t i r r e d i n t e r f a c e c o n t a c t o r . From Eq.
(Is), K A
F
1
+
K A S
1- --
S
n
(F /F ) 1 2
i f D is made l a r g e and t h e f o l l o w i n g r e f e r e n c e v a l u e s a r e u s e d :
F2
=
F1 area
=
=
780 c c / s e c = bismuth flow r a t e , 55 c c / s e c = s a l t flow r a t e , and
36.7/Ks.
Subs-ti-Luting v a l u e s of m a s s t r a n s f e r c o e f f i c i e n t from Table 3 i n t o Ey. ( 2 9 ) gives t h e following resul-ts:
21
22
if K
S
A i f I<
S
A
0.0042 cm/sec = l o w e s t e x p e r i m e n t a l v a l u e , 2
9 f t ; and
0.054 cm/sec = h i g h e s t e x p e r i m e n t a l v a l u e , 0.7 f t
2
.
These v a l u e s f o r t h e a r e a of t h e proposed contiactor would s e e m t o b e q u i t e reasonable.
However, t h e actual. a r e a which wou1.d be requi-red for a con-
t a c t o r i.n a proce:;sing
plant-. would be somewhat l a r g e r because the d i s t r i -
b u t i o n c o e f f i c i e n t i n t h e con-Lactor would n o t be as l a r g e a s was assumed i n tlne above c a l c u l a t i o n .
2 6
Conclusions
A new c o r r e l a t i o n h a s been developed to a c c o u n t
for t h e e f f e c t of
l a r g e d e n s i t y d i f f e r e n c e s and v a r i a t i o n s i n t h e s t i r r e r l e n g t h / p h a s e depth r a t i o .
The c o r r e l a t i o n g i v e n i n E q .
e x p e r i m e n t a l r e s u l t s f o r t h e water-mercury f o r the aqueous-organic systeifis r e p o r t e d
iin
(7) accurately predicts t h e system as w e l l as t h e r e s u l t s the literature.
A â&#x201A;ŹLow-
through, s t i r r e d - i n L e r f a c e conkactor w a s i n s t a l l e d i n t h e m i l d - s t e e l reductive extraction f a c i l i t y . salt--bismuth
Ma.ss t r a n s f e r r a t e s f o r a molten f l u o r i d e
systein were measured u s i n g t h i s e o n t a c t o r .
These measured
r a t e s f e l l between t h e predict.i.ons made by t3ie L e w i s and modified c o r r e l a t i o n s , e x c e p t when h i g h s t i r r e r r a t e s w e r e u s e d ; i n t h e l a t t e r c a s e s , h i g h m a s s t r a n s f e r r a t e s w e r e obtiained. coefficicnt prevail
,
I f t h e s e v a l u e s of mass t r a n s f e r
t h e r e q u i r e d mass t r a n s f e r area i n an MSBR p r o c e s s i n g
p l a n t would n o t be u n r e a s o n a b l y l a r g e .
23
3.
DEVELOPMENT OF THE METAL TRANSFER PROCESS: OF' ENGINEERING-SCALE EXPERIMENTS H . C.
CONTINUATION
Savage
The p r e s e n t p r o c e s s i n g f l o w s h e e t 1 3 u s e s t h e m e t a l t r a n s f e r p r o c e s s f o r removing rare e a r t h s from m o l t e n - s a l t b r e e d e r r e a c t o r f u e l salt.
In
t h i s p r o c e s s , f u e l s a l t t h a t i s f r e e of uranium and p r o t a c t i n i u m b u t cont a i n s t h e rare e a r t h s i s c o u n t e r c u r r e n t l y c o n t a c t e d w i t h bismuth c o n t a i n i r i q r e d u c t a n t t o e x t r a c t t h e r a r e e a r t h s i n t o t h e bismuth.
The bismuth stream,
which c o n t a i n s the r a r e e a r t h s and t h o r i u m , i s t h e n c o u n t e r c u r r e n t l y cont a c t e d w i t h LiC1.
Because of f a v o r a b l e d i s t r i b u t i o n c o e f f i c i e n t s , s i g n i f -
i c a n t f r a c t i o n s of t h e rare e a r t h s t r a n s f e r t o the L i C 1 a l o n g w i t h a
n e g l i g i b l e amount o f thorium.
The f i n a l s t e p s o f t h e process c o n s i s t i n
e x t r a c t i n g t h e r a r e e a r t h s from t h e L i C l by c o n t a c t w i t h bismuth having l i t h i u m c o n c e n t r a t i o n s o f 5 and 50 a t . %. Four e n g i n e e r i n g - s c a l e e x p e r i m e n t s (MTE-I,
-2,
-23,
- 3 ) have been
c a r r i e d o u t t o s t u d y t h e s t e p s i n t h e metal t r a n s f e r p r o c e s s and t o o b t a i n i n f o r m a t i o n such as m a s s t r a n s f e r r a t e s of t h e r a r e e a r t h s between t h e
s a l t and bismuth p h a s e s n e c e s s a r y f o r d e t e r m i n i n g t h e s i z e and type of equipment needed f o r t h e p r o c e s s .
The r e s u l t s o b t a i n e d i n t h e s e c x p e r i -
ments were r e p o r t e d p r e v i o u s l y . 14-17 The s e l e c t i v e removal of r a r e e a r t h s (lanthanum and 147Nd) from MSBK fuel c a r r i e r s a l t (72-16-12
mole
%
LiF-
BeF -ThF ) and t r a n s f e r t o L i - B i a c c e p t o r a l l o y were d e m o n s t r a t e d i n 2 4 14TE-3 w a s a l a r g e r - s c a l e e x p e r i m e n t , e x p e r i m e n t s MTE-1, - 2 , and -2B. which inc:luded f e a t u r e s s u c h as mechanical a g i t a t i o n of t h e s a l t and
metal p h a s e s t o improve m a s s t r a n s f e r r a t e s o f t h e rare e a r t h s a c r o s s t h e t h r e e salt-metal i n t e r f a c e s .
T'his e x p e r i m e n t was d e s i g n e d t o measure t h e
m a s s t r a n s f e r r a t e s a c r o s s t h e t h r e e i n t e r f a c e s as a f u n c t l o n of a g i t a t o r speed for comparison w i t h c a l c u l a t e d v a l u e s u s i n g a mass t r a n s f e r c o r r e 18 l a t i o n developed by J. B . L e w i s . Experiment MTE-3 (shown s c h e m a t i c a l l y in F i g . 6 ) c o n s i s t e d of t h r e e interconnected vessels:
a 14-in.-diam
f u e l s a l t r e s e r v o i r , a 10-in.-
d i a m s a l t - m e t a l c o n t a c t o r , and a 6 - i n . - d i m
rare-earth
stripper.
The s a l t -
m e t a l c o n t a c t o r was d i v i d e d i n t o two compartments t h a t were i n t e r c o n n e c t e d
t
24
25
t h r o u g h an opening i n t h e bottom of t h e d i v i d e r b y a p o o l of bismuth conThe s t r i p p e r c o n t a i n e d an L i - R i
t a i n i n g t h o r i u m and l i t h i u m .
so Lution.
A mechanical. a g i t a t o r w a s used i n each compartment of t h e c o n t a c t o r a n d
i n %he L i - B i s t r i p p e r t o promote mass t r a n s f e r cicross t h e rAree s a l t -
All vt:!ssels were f a b r i c a t e d o f carbon s t e e l arid had
metal i n t e r f a c e s .
nn o x i d a t i o n - r e s i s t a n t c o a t i n g of n i c k e l a Lurninide on t h e o u t s i d e s u r faces. T h e p u r p o s e of experiment MTE-3
w a s t o e v a l u a t e t h e contac:tor and
s t r i p p e r d e s c r i b e d above f o r use i n removing r a r e e a r t h s from ino1t.en-
F l u o r i d e and L i C l flow r a t e s w e r e a b o u t 1% of t-tlose
s a l t react:or f u e l .
r e q u i r e d f o r removing r a r e e a r t h s from a 1000-mr(e) MSRR. t h e phases were 72-16-12
temperature was about 6SO'C;
f u e l c a r r i e r s a l t , 0.13 a t .
2;
Th-Bi
of l i t h i u m a s r e d u c t a n t , and a 5 a t . In t h i s
~ U X ~ S S t,h e
the '7%-Bi
solut.ion.
The o p e r a t i n g
mole 2; LiF-BeF -ThF
2
s o l u t i o n c o n t a i n i n g a b o u t .LOO w t ppm %
Li-Ri
s o l u t i o n i n t h e str.i.pper.
rare e a r t h s a r e e x t r a c t e d from t h e c a r r i e r salt . i n t o Tlne rare e a r t h s a r c : e x t r a c t e d from the Th-Bi i n t o
molten L i C 1 and a r e s u b s e q u e n t l y s t r . i p p e d from t h e L i C l i n t o B i - L i Mas:?
4
alloy.
t r a n s f e r c o e f f i c i e n t s f o u radium, eiiropium, lanthanum, and neo-
dymium were measured d u r i n g 1 3 runs f o r comparison w i - t ' n values p r e d i c t e d
by l i t e r a t u r e c o r r e l a t i o n . l8
A g i . t a t o r s p e e d s of 100 t o 4 0 0 rpm were used
Many o f t h e mass t r a n s f e r coef f.i.cients w e r e fouiid to be s u b s t a ~ i i - _ i a . l . l y lower ( 4 t o 15%) t h a n p r e d i c t e d . l9
'I'ennination of
ti-le
MSX Eroyriim p r e -
c l u d e d f u r t h e r i n v e s t i g a t i o n of t h e mass t r a n s f e r :~-;itesarid p o s t o p e r a t i v e examination of t h e MTE-3 equipment t o d e t e r m i n e t;he r e a s o n f o r t h e lowerthan-expected t r a n s f e r r a t e s .
The s y s t e m w a s shut down and placed i n
s t a n d b y c i x i d i t i o n , w i t l r i a l l s a l t and metal p h a s e s frozen, i n February
1973. We p l a n t o c o n t i n u e s t u d i e s of the
111ass t r a n s f e r r a t e s o f
rrire e a r t h s
between fuel c a r r i e r s a l t I b i s m u t h , and L.i.C.1 i n a n e w exper j.ment. tlesign a t e d as XTE-3B.
New
.
vest'-' .,t.ls,
s a l t s , and b i s m u t i - 1 will be lised.
26
3.1
Examination of MTE-3 Equipment and Materials
Metal. t r a n s f e r experiment MTE-3 w a s m a i n t a i n e d a t a p p r o x i m a t e l y 650OC f o r a b o u t 1 y e a r
(%8700 h r ) .
During t h e f i n a l r u n ( E U - 9 ) ,
i n which
an a g i t a t o r speed o f 400 rpm was employed, f l u o r i d e s a l t was e n t r a i n e d i n t o the L i C l i n the contactor
I/
(2.1.0 w t % f l u o r i d e i n t o t h e L i C l ) .
This
r e s u l t e d i n t h e t r a n s f e r o f thorium i n t o t h e L i C 1 , from which it was subsequently e x t r a c t e d i n t o t h e L i - B i
solution i n the stripper.
After run
EU-9 t h e experiment w a s s h u t dowil, c o o l e d t o room t e m p e r a t u r e , and p l a c e d i n standby.
( T h i s w a s i n February 1973 when t h e MSR Program w a s t e r m i -
nated. ) Removal o f t h e t h r e e a g i t a t o r assemblies f o r examination o E t h e molybdenum s h a f t s and a g i t a t o r b l a d e s a n d , i f f e a s i b l e , r e u s e i n e x p e r i - ment MTE-3R r e q u i r e d t h a t t h e s a l t and m e t a l p h a s e s i n t h e c o n t a c t o r and s t r i p p e r v e s s e l s be m e l t e d .
A f t e r a l l h e a t e r c i r c u i - t s and r e c a l i b r a t i o n
of i n s t r u m e n t a t i o n had been checked, t h e c o n t a c t o r and s t r i p p e r v e s s e l s
were h e a t e d t o approximately 650째C and t h e a g i t a t o r assemblies were removed w i t h o u t d i f f i c u l t y .
The a g i t a t o r p o r t s w e r e immediately s e a l e d
w i t h b l a n k f l a n g e cover p l . a t e s and t h e v e s s e l s c o o l e d t o ambient tempera-
ture.
During t h e removal o f t h e a q i t a t o r s , a n a r g o n atmosphere w a s main-
tained i n tile vessels. A c u r s o r y v i s u a l . examination i n d i c a t e d t h a t t h e molybdenum s h a f t and
b l a d e s were i n good c o n d i t i o n . noted.
N o a r e a s o f heavy c o r r o s i o n a t - t a c k s w e r e
However, some a r e a s o f t h e s h a f t and b l a d e s c o n t a i n d e p o s i t s of
s a l t and metal which must be removed For a m o r e - d e t a i l e d and meaningful examination.
T h e r e f o r e , whether o r n o t t h e molybdenum a y i t a t o r can o r
s h o u l d be used i n experiment MTE-38 has n o t been d e t e r m i n e d .
(Note:
The s h a f t on t h e a g i t a t o r from t h e L i C l s i d e of t h e c o n t a c t o r w a s a c c i d e n t l y broken, a f t e r removal, i n an a t t e m p t t o remove t h e p i n h o l d i n g t h e molybdenum s h a f t t o t h e a g i t a t o r d r i v e u n i t , )
F i g u r e 7 i s a photograph
of t h e molybdenum a g i t a t o r s h a f t s as removed.
N o t e t h a k t h e a g i t a t o r from
t h e L i C l s i d e o f t h e c o n t a c t o r s h a f t i.s hollow a t t h e b r e a k p o i n t .
This
i s n o t i n a c c o r d w i t h t h e e n g i n e e r i n g drawing f o r t h e s h a f t (M12172 CD 027 E Rev. 5 ) , which i n d i c a t e s a s o l i d c o n s t r u c t i o n a t t h e broken a r e a s .
27
Fig. 7 .
Photograpn of a g i t a t o r shafts removed from VTE-3.
28
W e removed t h e tihermal i n s u l a t i o n from MTE-3
and some o f t h e s t a i n l e s s
s t e e l shim s t o c k s u r r o u n d i n g t h e e l e c t r i c h e a t e r s .
The o u t s i d e s u r f a c e s
of t h e carbon s t e e l v e s s e l s (ASTW-AlO6 Grade 13 w i t h a nominal compositi.on of F e ; C , 0 . 3 0 % max; M n , 0.29-1.06%; P I 0 . 0 4 8 % max; S I 0 . 0 5 8 % max; Si., 0 . 1 0 % min) were found t o be bad1.y o x i d i z e d due t o f a i l u r e of t h e oxidati.on-
r e s i s t a n t coating.
These v e s s e l s had been m a i n t a i n e d a t \ 6 5 O 0 C
hr). i m a t e l y 1 y e a r ("~8700
f o r approx-
The d e p t h o f o x i d a t i o n was e s t i m a t e d t o be
1/16 i n . o r l e s s and t h u s d i d n o t s i - q n i f i c a n t l y a f f e c t t h e mechanical i n t e g r i t y of t h e v e s s e l s
( i n i t i a l wall thickness
a t i n g c o n d i t i o n s o f MTE-3.
= 3/8
i n . ) a t the oper-
The o x i d a t i o n - r e s i s t a n t p r o t e c t i v e c o a t i n g
c o n s i s t e d o f 0.015- t o 0.020-in.-t:hick
n i c k e l a l u m h i d e * a p p l i e d by flame
s p r a y i n g w i t h w i r e flame s p r a y equipment.
We c o n t a c t e d a r e p r e s e n t a t i v e
of ITETCO, who recommended t h a t - a much b e t t e r c o a t i n g would be o b t a i n e d by
u s i n g a nickel-chromium a l l o y w i t h aluminum composite i ~ npowder form (ME'i'CO N o .
P443-10) a p p l i e d w i t h plasma s p r a y equipment.
Test sections
of carbon s t e e l . p i p e w i t h t h e two c o a t i n g s d e s c r i b e d above have Seen p r e -
p a r e d f o r comparat.ive e v a l u a t i o n . We o b t a i n e d samples of t-he s a l - t s ( f u e l c a r r i e r s a l t and L i C 1 ) ant3 bismuth from t h e YTE-3 vesse1.s by removing a 2-i.n.-dLam plug a c r o s s each salt-metal i n t e r f a c e .
("-1/3
A l a y e r of inaterial o E d i f f e r e n t s t r u c t u r e
i n . t h i c k ) appeared t o e x i s t between t h e L i C 1 - - T J i - B i
phases i n t h e
s t r i p p e r , whereas no comparable F i l m was s e e n at: tihe i n t i c r f a c e s between t h e TAiC1--Bi-Th and t h e fuel. c a r r i e r salt--31-Th
p h a s e s in t h e c o n t a c t o r .
C o r r o s i o n of t h e i n s i d e s u r f a c e s of t h e 2 - i n . -dj.am v e s s e l .wall s e c t i o n s appeared minimal on vi-sua1 examination of t h e 2 - i n . -diam pl.uys. A
small (Ql/8- by % 1 / 4 - i . n . )
sample cf bismuth w a s t a k e n a t each of
t h e t h r e e m e t a l - - s a l t i n t e r f a c e s f o r m e t a l l o g r a p h i c examination.
Each
s e c t i o n i n c l u d e d t h e bismuth s u r f a c e i n contact. w i t h t h e s a l t phase. Photomicrographs of t h e s e samples a r e shown i n P i g s . 8-10.
A s seen,
t h e r e j.s some f o r e i g n m a t c r i a l a t e a c h s u r f a c e of t h e bismiith which was ii?
c o n t a c t w i t h t h e sa7.i: p h a s e ( f l u i d c a r r i e r s a l t and L i C l ) .
Whether
t h i s m a t e r i a l w a s p r e s e n t d u r i n g o p e r a t i o n of m e t a l t r a n s f e r experiment ____ $;
._
MEL'CO NO. M405-I 0 (ME'TCO ,
IYIC.
,
Westbury L.1. , N.Y. )
-
29
BISMUTH ..
Fi-g. 8 . Photomicrograph o f B i - T h phase F r o m t h e c o n t a c t o r at t h e flUOri.de c a r r i e r salt i n t e r f a c e i n experiment MTE-3 - As pc3lished. LSOX.
c
30
O R N L DWG. 74-10114
.
..
I
.
BISMUTH
F i g . 9. Photomicrograph of R i - T h phase from the contactor at the LiCl interface in experiment IITE-3. As polished. 150X.
31
32
MTE-3 o r s e g r e g a t e d a t t h e s u r f a c e when t h e phases were c o o l e d w i t h o u t a g i t a t i o n i s unknown. Scanning e l e c t r o n microprobe a n a l y s e s were performed to i d n n t i f y t h e
material s e e n a t t h e i n t e r f a c i a l s u r f a c e s of t h e bismuth. shown i n F i g s . 11-13.
Results a r e
The bismuth i n c o n t a c t w i t h t h e f l u o r i d e c a r r i e r
s a l t c o n t a i n e d a s u r f a c e l a y e r which was e n r i c h e d w i t h thorium and i r o n .
Thorium and i r o n , along w i t h s o m e mangariese arid lanthanum
(lanthanum was
one of t h e r a r e e a r t h s used to measure inass t r a n s f e r r a t e s in MTE-3) , were i d e n t i f i e d a t t h e s u r f a c e of t h e bismuth i n c o n t a c t wi?h t h e L i C l i n t h e contactor.
I r o n arid thorium were a l s o identxified a t t h e s u r f a c e of the
b i s n u t h i n c o n t a c t w i t h t h e LiCl i n t h e s t r i p p e r .
The Ri-ll'h and t h e L i -
Bi p h a s e s , as w e l l as t h e s a l t p h a s e s , c o n t a i n e d s i g n i f i c a n t amounts o f i r o n ( s e e Table 4 ) , undoubtedly as a r e s u l t o f c o r r o s i o n 015 t h e carbon A p e t r o g r a p h i c examination w a s made of
s t e e l vessels.
a sample of t h e
f l u o r i d e s a l t from t h e c o n t a c t o r a t a p o i n t n e a r t h e Bi-Th p h a s e and -the tank wall.
This examination i n d i c a t e d t h a t t h e sample c o n s i s t e d p r i n c i -
p a l l y of c r y s t a l s o f 3LiF-T;iF
4'
According t o t h e p h a s e diagram of t h e
LiF-BeF -ThF 3IAF-ThF would be e x p e c t e d t o c r y s t a l l i z e 2 4' 4 from s o l u t i o n on c o o l i n g - - e s p e c i a l l y a.t: or n e a r t h e t a n k w a l l . No o x i d e s '72-16-12 mole
%
were fourid i n t:he sample. A s e c t i o n of t h e L i - B i - - L i C l
a c r o s s t h e i n t e r f a c j - a l a r e a from I:he
s t r i p p e r (which i n c l u d e d t h e l a y e r of material o f d i f f e r e n t s t r u c t u r e betmeen t h e L i - B i microscopy.
and t h e L i C l ) is b e i n g examined by s c a n n i n g e l e c t r o n
N o r e s u l t s have been o b t a i n e d as y e t .
3.2
Stzatus o f Experiment MTE-3B
We p l a n to c o n t i n u e measuring t h e m a s s t r a n s f : ? r r a t e s of r a r e e a r t h s between salt and bismuth i n a riew e x p e r i m e n t , which i s d e s i g n a t e d a s M'TE-3B.
The v e s s e l s , s a l t s , and bismuth t h a t were used f o r MTE-3 will
be d i s c a r d e d .
N e w carbon s t e e l v e s s e l s a r c b e i n g f a b r i c a t e d , w i t h mid-
June b e i n g t h e esti-mated completion d a t e .
A f t e r t h e v e s s e l s have been
r e c e i v e d , a s s e m b l y o â&#x201A;Ź t h e equipmen-t w i l l . b e g i n .
Based on t h e r e s u l t i s o f
MTE-3, i n i t i a l e x p e r i m e n t s w i l l be made at: a g i t a t o r s p e e d s up t o 300 rpm.
33
Y-124404
Backscattered Electrons
B i LQ X-Rays
5
i
8
ThMa X-Rays
FeKa X-Rays
Fig. 11. Electron beam :;c,mni.ng images of e Iernexits in t h e B i - T l i phase f r o m the c o n t a c t o r at t h e f l u o r i d e s a l t i n t e r f a c e in exper-imc~rit m~2-3
*
K
U
2 *
al
L
..0 .. w 13 4 +.-
U
:: 19
U
Y
m
34
ej
Y
i
35
Buckscattered Electrons
B i La X-Rays
ThMa X-Rays
Fe Ku X-Rays
Fig. 13. Electron beam scaririing images of elements in t h e Z,i -Bjp h C ~ s efrom t h e stripper a t the 1 , i C I salt i n t e r f a c e in experiment P I T E - - ~ .
36
Table 4 .
Lron c o n t e n t o f samples o f m e t a l and 5 a l t p h a s e s from metal t r a n s f e r experiment MTE-3
F l u o r i d e salt from c o n t a c t o r Ai-Th
,
Bi-:rh
, LiCl
3 2 0 , 88a
f l u o r i d e - s a l t s i d e of coizt1actor s i d e of contactlor
2500
L i C l from c o n t a c t o r
3500
L i C l from s t r i p p e r
Li-Bi
1100
650
from s t r i p p e r
1400 .I_
a R e s u l t s f o r two d i f f e r e n t samples.
All other r e s u l t s are f o r oilc sample.
E a r l i e r d a t a showed t h a t improved t r a n s f e r r a t e s were observed w i t h i n c r e a s i n g s p e e d ; however, a t 400 rpm, f l u o r i d e salt w a s e n t r a i n e d i n t o
the L i c l s a 1 t . l 7 We p l a n t o use 14'7Nd as t h e r a r e e a r t h .
A s i n experi-
ment NTE-3,
t r a n s f e r r a t e s can r e a d i l y be followed by c o u n t i n g t h e 0 . 5 3 147 A l s o , t h e r e l a t i v e l y s h o r t h a l f - l i f e of MeV gamma e m i t t e d by 147Nd. Nd (11 d a y s ) w i l l a l l o w experiments t o be r e p e a t e d a f t e r a r e a s o n a b l e w a i t i n g
period.
37
4
CONTINUOUS FLTJOKTNATOR DEVELOPMENT
R. M.
4-1
Counce
J.
K. Hightower, Jr.
A u t o r e s i s t a n c e ilea-ting Tests
A n o n r a d i o a c t i v e experiment
t o d e m o n s t r a t e t h a t a l a y e r of f r o z e n s a l t
w i L1 provide p r o t e c t i o n a g a i n s t corrosion i n A continuous f l u o r i n a t o r r e q u i r e s a h e a t s o u r c e i n t h e m o l t m i s a l - t which i s immune t o a t t a c k by 20 that autoresistance t h e gaseous fluorine. We have p r e v i o u s l y shown h e a t i n g o f t h e s a l t i s f e a s i b l e , and have d e s i g n e d and b u i l t a f l u o r i n a t o r mock-up t o test; a d e s i y n f o r an e l e c t r o d e s i d e a r m to keep t h e e l e c t r o d e
o u t o f tile f l u o r i n e s t r e a m .
21.
F i v e e x p e r i m e n t s (Am-1 tiirough - 5 ) were r u n i n t h e f l u o r i n a t o r mockup b e f o r e t h e MSR. Program was i n t e r r u p t e d (between J a n u a r y 1973 and
.
January 1 9 7 4 ) period.
T h i s equipment remained i d l e , but irit:act.,
during t h i s
T h e equipment has now been r e t u r n e d t o operat.i.ng c o n d i t i o n , and
t e s t i n g o f a u t o r e s i s t a n c e h e a t i n g i n .i.t has been resumed. Experiments AWY3-6.4, r e p o r t per:Lod.
-613, - 7 ,
I n r u n s RI-IT3-6A,
- 8 , arid - 9 were carri-ei'l o u t , ( l u r i n g t h i s
-6I3, -8, and - 9 ,
the autoresistance
h e a t i n g w a s begun when t h e w a l l t e m p e r a t u r e o f t h e test sect:ion was c o o l e d t o 350"C, t h e lowest t e m p e r a t u r e a t which l i q u i d can e x i s t .i.n t:tic?
BeF -ThF system. 2 4
L~F-
N o i n t e r n a l h e a t i n g was a t t e m p t e d .in r u n AHT3-7.
The c i r c u i t r e s i s t a n c e d u r i n g cooldown i.n r u n s AWT3-6A and -6B
remained a t a b o u t 0.01 t o 0 . 0 3 SI u n t i l t h e wall t e m p e r a t u r e dropped t o a p p r o x i m a t e l y fsOO째C, where t h e fuel s a l t b e g i n s t o f r e e z e .
t e m p e r a t u r e d e c r e a s e d from 500'C about 350째C,
As
the w a l l
t o 350"C, the resistance increased; a t
it increased dramatically.
Presumably, t h i s o c c u r r e d because
t h e s a l t f i l m becomes c o m p l e t e l y nonconducting o n l y when t h e t e m p e r a t u r e
is s u f f i - c i e n t l y low t o p r e c l u d e t h e exi!;tence of l i q u i d .
.In t h e LiF-BeF -
ThF4 system, no l i q u i d can e x i s t below 3 5 0 째 C . When t h e w a l l t e m p e r a t u r e reached 3 5 0 째 C , a u t o r e s i s t a n c e heatiny w a s started.
W e had platiried t o i n c r e a s e the c u r r e n t t h r o u q h t h e salt u n t i l
t h e wall t e m p e r a t u r e s i n d i c a t e d s t e a d y s t a t e
I
However, s t e a d y s t a t e w a s
2
38 not attained.
I n s t e a d , t h e r e s i s t a n c e through t h e c o n d u c t i n g p a t h
d e c r e a s e d suddenly from 0 . 5 SZ i n run 6 A and 0 . 4
R i n r u n 6B t o z e r o ,
i n d i c a t i n g a l o s s of f i l m i n t e g r i t y a.nd subsequent s h o r t i n g of t h e h e a t i n g current. I n c r e a s e s i n t h e w a l l t e m p e r a t u r e s a t t h e time o f s h o r t i n q i n d i c a t e d t h a t t h e s h o r t i n g o c c u r r e d n e a r t h e bend i n t h e e l e c t r o d e si.dearm n e a r e s t
to t h e e l e c t r o d e . densities.
T h i s w a s thought t o be due t o l o c a l i z e d h i g h c u r r e n t
The sidearm and o t h e r c r i . t F c a 1 a r e a s o f t h e t e s t v e s s e l have
been modeled t o d e t e r m i n e i f l o c a l i z e d h i g h c u r r e n t d e n s i t i e s might e x i s t . . The modeling p r o c e d u r e and results a r e d i s c u s s e d i n t h e n e x t s e c - t i o n . I n run AHT3-7, t h e wall t e m p e r a t u r e o f t h e t e s t v e s s e l w a s lowered t o 425OC and t h e remaining l i q u i d s a l t was t r a n s f e r r e d to t h e f e e d t a n k . I n t e r n a l h e a t g e n e r a t i o n was n o t a t t e m p t e d .
The f r o z e n s a l t w a l l w a s
i n s p e c t e d a f t e r t h e equipment had heen c o o l e d t o room t e m p e r a t u r e .
The
s a l t w a s a l m o s t c o m p l e t e l y f r o z e n a c r o s s t h e v e s s e l just above t h e lower sidearm i n l e t , a l t h o u g h a much t h i n n e r s a l t l a y e r (%3/4 i n . ) w a s p r e s e n t j u s t below t h e i n l e t and h i g h e r i n t h e t e s t s e c t i o n .
T h i s f r e e z i n g was
caused by c o n t a c t of t h e unheated a r g o n w i t h t h e l i q u i d s a l t .
Heaters
have been added on t h e arcjon l i n e s t o the test v e s s e l t o h e l p a l l e v i a t e t h i s problem. A f t e r t h e e f f e c t s of t h e c o l d a r g o n had been r e d u c e d , t h e maximum r e s i s t a n c e d u r i n g a u t o r e s i s t a n c e h e a t i n g i n c r e a s e d d r a m a t i c a l l y i n AHT3-6A and -6B to 0 . 5 and 0 . 4
R, respectively.
I n r u n AHT3-8, which w a s made
a f t e r h e a t e r s had been added on t h e argon l i n e s , t h e maximum r e s i s t a n c e
w a s 2.4 R during a u t o r e s i s t a n c e heatiny.
During t h e p e r i o d o f a u t o r e s i s -
t a n c e h e a t i n g ( 2 5 m i n ) , t h e c u r r e n t w a s i n c r e a s e d from 5 A t o 2 4 A.
The
s a l t temperatures continued t o decrease during t h i s t i m e b u t appeared t o be approaching a c o n s t a n t v a l u e (above room t e m p e r a t u r e ) .
A f t e r 25 min
of a u t o r e s i s t a n c e h e a t i n g , t h e r e s i s t a n c e suddenly d e c r e a s e d w h i l e t h e t e m p e r a t u r e r o s e r a p i d l y i n t h e hend oE t h e e l e c t r c d e sidearm n e a r t h e
e l e c t r o d e , i n d i c a t i n g t h a t t h i s was t h e a r e a i n which t h e s a l t film had
melted Experiment AHT3-9 was performed u s i n g t h e s a m e p r o c e d u r e a s b e f o r e , e x c e p t t h a t t h e c u r r e n t w a s l i m i t e d t o a maxinium of 1 7 A .
The e l e c t r o d e
39
i n t h e s e tests c o n s i s t e d of a l / 2 - i n .
Inconel tube extending t o t h e i n t e r -
s e c t i o n of t h e c e n t e r l i n e s of t h e v e r t i c a l s e c t i o n and t h e s l o p i n g s e c t i o n of t h e e l e c t r o d e s i d e a r m (see r e f . 21).
In the f i r s t nine runs, the salt
d e p t h i n t h e e l e c t r o d e s i d e a r m above t h e end o f t h e t u b e w a s measured by bubbling argon through t h e tube.
Before run A H T 3 - 9 w a s s t a r t e d , t h i s
measurement had i n d i c a t e d t h a t t h e s a l t l e v e l i n t h e s i d e a r m w a s lower t h a n t h a t measured i n t h e main compartment the t e s t vessel. t h i s run.
w a s 4.3 2.
( g a s - s a l t c o n t a c t i n g zone) o f
Also, abnormally h i g h r e s i s t a n c e s were o b s e r v e d d u r i n g
The h i g h e s t r e s i s t a n c e d u r i n g a u t o r e s i s t a n c e h e a t i n g i n AIIT3-I) A t t h e end o f t h e e x p e r i m e n t , t h e s a l t w a s t r a n s f e r r e d t o t h e
f e e d t a n k from t h e t e s t v e s s e l .
The c a p t i v e volume of s a l t i n the e l e c -
t r o d e s i d e a r m c o u l d n o t b e removed.
A f t e r t h e equipment had beer? allowed
t o c o o l , t h e e l e c t r o d e w a s removed and examined. 1/2-in.
The lower 6 i n . of t h e
I n c o n e l t u b e of which t h e e l e c t r o d e was made was m i s s i n q .
Thus
Ear, w e have no e x p l a n a t i o n f o r t h i s phenomenon. 4.2
D i s t r i b u t i o n of C u r r e n t D e n s i t i e s i n t h e A u t o r e s i s t a n c e Heating Equipment
W e have c o n s t r u c t e d an e l e c t r i c a l a n a l o g of t h e e l e c t r o d e sidearm i n o r d e r t o d e t e r m i n e if t h e r e a r e r e g i o n s of l o c a l i z e d h i g h c u r r e n t d e n s i t y which might be c a u s i n g t h e f r o z e n s a l t f i l m n e a r t h e e l e c t r o d e t o melt. The a n a l o g w a s made from e l e c t r i c a l l y c o n d u c t i n g p h o t o g r a p h i c paper* c u t i n t h e shape o f t h e s i d e a r m and t h e c o n t a i n e d e l e c t r o d e .
With t h e u s e of
t h i s s p e c i a l p a p e r , a two-dimensional model may be c o n s t r u c t e d f o r t h e s t u d y of s t e a d y - s t a t e c u r r e n t flow i n s i m p l e o r complex geometry.
22
The g e o m e t r i c model used i s o p o t e n t i a l nonconducting w a l l c o n d i t i o n s , which were r e p r e s e n t e d i n t h e model b y lines of c o n d u c t i v e p a i n t .
**
BY
g i v i n g t h e opposing w a l l s s e p a r a t e and d i s t i n c t p o t e n t i a l s , w e w e r e a b l e
t o produce an e l e c t r i c f i e l d which c o u l d b e mapped u s i n g a high-impedance voltmeter w i t h an e l e c t r i c p r o b e . *Grade 5 0 6 - L , d i s t r i b u t e d by Knowlton B r o s . , Watertown, N . Y, T h e resist a n c e of t h i s p a p e r w a s s u f f i c i e n t l y h i g h f o r u s e i n t h i s s t u d y .
**
S i l v e r p a i n t o b t a i n e d from Dupont E l e c t r o c h e m i c a l s , Wilmiiigton, E e l .
40
The i s o p o t e n t l i a l lines g e n e r a t e d between t h e walls i n t h i s manner r e p r e s e n t e d c u r r e n t flow l i n e s .
By s h i f t i n g t h e e l e c t x o d e s 90° t o t h e
ends o f t h e model, t h e i s o p o t e n t i a l s would r e p r e s e r i t t h e p o t e n t i a l g r a d i e n t i n t h e system. The Bivar p o t e n t i a l s o u r c e and probe used â&#x201A;Ź o r measuring t h e e l e c t r i c f i e l d were made by E l e c t . r o n i c A s s o c i a t e s , I n c . A n accompanying V a r i p l o t t e r ,
,
o f Long Beach, N e w J e r s e y .
a l s o made by E l e c t r o n i c A s s o c i a t e s , I n c . ,
p r o v i d e d t h e c o n n e c t i o n s t o t h e v o l t a g e s o u r c e and a n i n s u l a t e d s u r f a c e
t o h o l d t h e model.
A high-impedance v o l t m e t e r w a s r e q u i r e d t o measure
the field potentials. The l i n e s i n F i g s . 14-1.6 r e p r e s e n t c u r r e n t strzarn l i n e s .
The d i - s t a n c e
between two stream lines i n F i g . 1 4 r e p r e s e n t s t h e p a s s a g e of 1 2 . 5 % of the t o t a l current.
I n E'igs. 1 5 and 1.6, t h e d i s t a n c e between s t r e a m lines
r e p r e s e n t s 1 0 % of t h e t o t a l c u r r e n t . F i g u r e s 1 4 and 15 show t h a t t h e r e a r e no r e g i o n s o f abnormally h i g h c u r r e n t d e n s i t i e s i n t h e v i c i n i t y of t h e two bends i n t h e e l e c t r o d e s i d e -
arm.
The p r e s e n t sidearm d e s i g n seems a d e q u a t e w i t h r e g a r d t o 1-ocalized
h e a t generat.i.on r a t e s . F i g u r e 1 6 shows an a l t e r n a t e e l e c t r o d e d e s i g n which would f u r t h e r r e d u c e l o c a l i z e d h e a t i n g a t t h e sidearm bend n e a r -the e l e c i x o d e .
This
d e s i g n h a s t h e a d d i t i o n a l a d v a n t a g e t h a t it could also lie used as t h e device f o r introducing t h e feed t o t h e f l u o r i n a t o r without f e a r of impinging a j e t o f h o t s a l t a g a i n s t t h e f r o z e n wal.7. snd d e s t r o y i n g the i n s u l a t i n g f i l m near t h e e l e c t r o d e .
41
OHNL D W G 7 4 - 7 3 2 6
F i g . 1 4 . C a l c u l a t e d c u r r e n t d i s t r i b u t i o n in t h e e l e c t r o d e sidearm of a u t o r e s i s t a n c e h e a t i n g t e s t AHT-3. The p e r c e n t a g e of the to.ka1 c u r r e n t f l o w i n g between two stream :Lines i s equal t o t h e d i f f e r e n c e between t h e numbers on t h e stream l i n e s .
42
ORNI. D W G 74-6372
3
Fig. 15. Calculated current distribution at the junction of the electrode sidearm and the fluorination section in autoresistance heating test AHT-3. The percentage of total current flowi.ng between two stream lines is equal to the difference between the numbers on t h e s t r e a m lines.
43
100
ORNL DWG 74-7328
3
F i g . 16. Calculated c u r r e n t d i s t r i b u t i o n i n t h e e l e c t r o d e s i d e a r m u s i n g a new e l e c t r o d e design. The p e r c e n t a g e of t h e t o t a l c u r r e n t flowing between t w o stream l i n e s i s equal t o t h e d i f f e r e n c e between the numbers on t h e stream l i n e s .
44
5.
REFERENCES
Lewis, Chem. Eng. S c i . 3 , 248-59
1.
J . B.
2.
W.
J . McManamey, Chem. Eng. S e i .
3.
G.
R. A. Mayers, Chem. Eng. S c i . 1 6 , 69-75
4.
J . A , Klein
5.
(1954).
18, 1 2 3 - 3 2 (1961). I
(1961).
, i n E n-_g i n e e r i n g Development S t u d i e s f o r . M o l t e n - S a x Breeder Reactor g-rocessinq N o . 1 4 , OmL-TM-4018 ( i n p r e p a r a t i o n )
.
J. A . K l e i n , i n Enyirieerinq Developmcnt_Studies f o r M o l t e n - S a l t Breeder Reactor-zLocessing N o . 1 5 , ORNL-TM-4019 ( i n p r e p a r a t i o n ) .
I
6.
7.
Chem. Technol.. Div. Annu .-.-. P r o g r . Rept. Mar .-_ 31 pp. 23-25.
1 9 7..... 3 , OWL-4883,
B. A . Hannaford, C . W . K e e , and T,. E . PkNeese, MSR P r o g r a m Semiannu. P r o q r . Rept..- Feb. 2 8 , 1971, .... ORNL-4676, p . 2 5 6 . ^
8.
Hannaford e t al. , MSlS-Program Semian;;.!. 1971., ORNL-4728, p . 2 1 2 .
R , A.
P r o g r . Rept. Auq. .3&-.-
_.I.-
9.
B. A. Hannaford, C . W. Keel and L . E . McNeese; E n q i n e e r i n g D e v e l o E ment: S t u d i e s f o r :4olten-Salt Breeder Reactor l-’rocessing--No. 8 , ORNL-TM-3259 , p 6 4 . I
10. B. A . Hannaford, C . W . Kee, and
1;. E . McNecse, E n g i n e e r i n g Develop:; ment Studies.--for Molten-Salt_-Bireeder. Reactor P r o c e s s i n g No. 9 , OWL-TM-3259, p . 1 5 8 .
11.
B. A . EIannaford, C. W . Keel and L. E . McNeesc, E n g i n e e r i n g Ilevelop-ment S t u d i e s fo~--J40l.ten-Salt Breeder Reac-tor P r o c e s s i n x t o . 10, OWL-TM-3352,
pp, 1 2 - 2 0 .
12.
A. S. Foust et: al., Princip2k.s o f Unit O p e r a t i o n s , p . 21.0, Wiley, New York, 19‘00.
13.
E S R Program Semiannu. P r o g r 179-83.
14.
L. E . McNeese , E n g i n e e r i n g l&?~-zlopment S t u d i e s f o r MolZgn-Salt Breeder 2.eacto.r P r o c e s s i n g N o .-?, ORNL-TPI-3257 , pp. 2 9 - 4 6 .
15.
.
Rept
.
Aug. 3A-!.-. 1971 , ORNL--4’?28 I pp.
E. McNeese, E n g i n e e r i n g Development St~Llies f o r -MoIt:en-SalL Breeder _. . lieac-For Procnssine.No...9, ORNT,--TM-3259 , pp. 167-94.
L.
I
IS.
L. E . IvlcNecse , F-n-giL!s&nq Development Stud:ies f o r P,lolten-Sa& Brecder Reactor P r o c c s s i n q - - - l c . 11, ORNL-TM-3774 (in preparation).
45
E . McNeese, E n g i n e e r i n g Development studies â&#x201A;Ź o r Molten-Salt Breeder R e a c t o r P r o c e s s i n g N o . 1 7 , ORNL-TM-4178 ( i n p r e p a r a t i o n ) .
17.
L.
18.
J . R. L e w i s , Chem. Eng. S c i .
19.
3 , 248-59
I
(1954).
Chem. Technol. Div. Annu. P r o g r . Rept. M a r . 31, 1973, - ORNL-4883,
p. 2 5 .
Hightower , Jr. , w i n c e r i n g Development S t u d i e s f o r M o l t e n - S a l t Breeder R e a c t o r P r o c e s s i n g N o . 1 6 , OWL-TM-4020 ( i n p r e p a r a t i o n ) .
20-
J . R.
21
J. R. Hightower, J r .
22.
C . E'. Kayan, "An E l e c t r i c Geometrical Analogue f o r Complex Heat F l o w , " Trans. RSM!X ._ 67 (91, 713-16 (1945).
, E n g i n e e r i n y Developinent S t u d i e s for Molten-Salt Breeder R e a c t o r P r o c e s s i n y No. 1 7 , ORNL-TM-4178 ( i n p r e p a r a t i o n ) .
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