HOME HELP
C m I C A L TECHNOLOGY DIVISION U N I T OPERATIONS SECTION
LOW-PRESSURE DISTILLATION QP A PORTIOiV OF THE FUEL C J E K I ~ RSALT FROM THE MOLTEN SALT REACTOR EXPmIm?JT
J. L. B. H.
W. Kigh-tower, Jr. E. McMeese
A. flannaford B. Cochran, Jr.
AUGUST 1971
This report was prepared as am account of work sponsored by the United Stater Government. Neither the United States nor the United States Atomic Energy Commission, nor any of their employees, nor any of their contractors, subcontractors, of their employees, makes any warranty, express or implied, or assumes any legal liability OK responsibility foe the accuracy, completeness or usefulness of any information, apparatus, produch oe process disclosed, or represents that its use would not infringe prhately owned rights.
OAK RIDGE NATIOHBL LBQRBTORY Oak Ridge, Tennessee operated by UNIOR CAl3BIDE CORPORATION U.S.
...-..;5 .:.:..A.
for %he ATOMIC EilTERGY COMMISSION
.
L.
iii CONTENTS
..... ... .<w .,. ..
.
Page
................. INTRODUCTION . . . . .. .. . BESCRIPTLON OF EQUIP,mm . .. . . . 2.1 Process Equipment . .. . . . 2.2 Instrumentation . . . . . . 2.2.1 Measurement and Control of Temperature . 2.2.2 Measurement and C o n t r o l of Pressure . . 2.2.3 Measurement and Control of Liquid Level . . 2.2.4 Wadktion Instrumentation . . 2.2.5 Instrument Panel . .. . . 2.3 Condensate Sampler . . .2*4 Location of Equipment at the MSRE . . . . DESCRIPTION OF DISTILLATION OPERATION .. . ~STEtACT..........
E. 2.
e
e
e
e
e
e
a
*
a
e
e
a
a
e
e
e
e
e
e
a
e
a
e
a
e
a
a
e
a
a
e
e
e
e
a
e
e
a
3.
a
4.1
. .
Sumnmry of Experimental Data
- .
~ e s d t sof
a
a
e
e
e
e
e
.
a
.
Relative Volatility Calculations
.
e
4.4.3 Contamination samples 4.hc.h Inaccurate Analyses a
e
e
e
e
e
.
.
a
e e
=
-
a
e
17 20
a
e
20
a
.a
e
e
.
-
..
e
a
a
e
a
e
4.4 Possible Explanations of Calculated Results 4.4.1 Entrainment of moplets of S t i l P - P o t Liquid 4.4.2 Concentration Polarization .. a
a
e
e
..
3
e
a
e
a
e
4.2 Material Balance Calculations k,3
a
e
e
e
a
e
3
a
*
a
a
1
e
a
a
e
i
a
.
.
27
e
28
-
33
.
42
a
e
.
.
e
41
4? 45 46 43
48 7.
...................
REFERENCES.......
8. APPENDIX: ANALYSES OF EXPmImNT
49
SAMPLES FROM TU3 MSRE DISTILLATION
.
e
a
-..
o
.
.
.*.. .
a
e
e
e
a
51
b
LOW-PRESSURE DISTILEATION OF A PORTION OF THE FUEL CARRIER SALT' FROM TKF: MOLTEN SALT REACTOR EXFEPIIMENY
J. 8. Hightower, J r . L. E . VcNeese B. A. Hannaford H. D, Cochran, J r .
ABSTRACT An experiment t o demonstrate t h e high-temperature low-pressure d i s t i l l a t i o n o f i r r a d i a t e d Molten S a l t Reactor Experiment ( N S R X ) f u e l c a r r i e r salt has been s u c c e s s f u l l y conpleted. A t o t a l of 12 l i t e r s of ISERE f u e l c a r r i e r s a l t w a s d i s t i l l e d i n 23 h r of t r o u b l e - f r e e o p e r a t i o n w i t h s t i l l p o t temlser-atures i n t h e range gOO-980"C and condenser press u r e s i n t h e range 0.1-0.8 t o r r . Eleven condensate samples were t a k e n during t h e course of t h e run a t i n t e r v a l s of approximately 90 min and were subsequently analyzed f o r L i , ~ e ~, r , 6 3 7 c s , 9 5 ~ r ,l44ce, 1 4 7 ~ n ,155~u,g l ~ 9QSr, , and 89sr. E f f e c t i v e r e l a t i v e v o l a t i l i t i e s w i t h r e s p e c t t o LiF, f o r Be and Zr were i n good agreement w i t h v a l u e s measured p r e v i o u s l y i n t h e l a b o r a t o r y . E f f e c t i v e r e l a t i v e v o l a t i l i t i e s fsr t h e s l i g h t l y v o l a t i l e materials lk4Ce, 91Y, g0Sr, and 89Sr were found t o b e much h i g h e r t h a n v a l u e s measured in t h e l a b o r a t o r y . The h i g h values w e b e l i e v e d t o be t h e r e s u l t of contamination from o t h e r K R E s a l t samples, although c o n c e n t r a t i o n p o l a r i z a t i o n may have a l s o been a c o n t r i b u t o r . The e f f e c t i v e r e l a t i v e voha t i l i t y f o r l37Cs was found t o be only 20$, c r l e s s , of t h e v a l u e measured i n t h e l a b o r a t o r y ; no e x p l a n a t i o n sf t h i s discrepancy i s a v a i l a b l e . Although t h e e f f e c t i v e r e l a t i v e v o l a t i l i t i e s f o r t h e l a n t h a n i d e s were found t o b e h i g h e r t h a n a n t i c i p a t e d , t h e v a l u e s observed would s t i l l a l l o w adequate recovery of 7LiF from w a s t e salt streams by d i s t i l l a t i o n .
1. Low-pressure d i s t i l l a t i o n may be r e q u i r e d i n o r d e r t o recover v a l u a b l e c a r r i e r s a l t components from waste s a l t streams coming from t h e f u e l p r o c e s s i n g p l a n t of a molten-salt ...,...,..,..................
-.&/
breeder r e a c t o r (MSBR)
T y p i c a l l y , 'LiF
would be vaporized and recovered, l e a v i n g a l i q u i d h e e l
more c o n c e n t r a t e d i n t h e l e s s v o l a t i l e l a n t h a n i d e f i s s i o n p r o d u c t s ( a s fluorides).
This heel would t h e n b e d i s c a r d e d .
The f i n a l stage of a
three-phase experimental program t o s t u d y and demonstrate t h e f e a s i b i l i t y o f d i s t i l l a t i o n f o r decontaminating c a r r i e r s a l t components of l a n t h a n i d e f i s s i o n products i s d e s c r i b e d i n t h i s r e p o r t .
The experimental program
included measurements of r e l a t i v e v o l a t i l i t i e s of s e v e r a l l a n t h a n i d e and a l k a l i n e - e a r t h f l u o r i d e s i n mixtures of LiF and BeF2, E ' 2 t h e operat i o n and t e s t i n g of a l a r g e s i n g l e - s t a g e s t i l l u s i n g f u e l c a r r i e r salt from t h e Molten S a l t Reactor Experiment (MSRE) w i t h simulated f i s s i o n produ c t ~ ~ " ,and, as d e s c r i b e d h e r e , a demonstration of t h e d i s t i l l a t i o n process using i r r a d i a t e d f u e l c a r r i e r s a l t from t h e MSRE. The o p e r a t i o n o f t h e d i s t i l l a t i o n equipment w i t h u n i r r a d i a t e d s a l t
had t h e following o b j e c t i v e s : l a r g e , low-pressure,
(1)o b t a i n i n g o p e r a t i n g experience w i t h
high-temperature d i s t i l l a t i o n equipment; ( 2 ) in-
v e s t i g a t i n g entrainment r a t e s and s e p a r a t i o n i n e f f i c i e n c i e s due t o conc e n t r a t i o n g r a d i e n t s i n t h e s t i l l p o t ; ( 3 ) measuring d i s t i l l a t i o n rates under a v a r i e t y of c o n d i t i o n s ; and
(4)
uncovering unexpected d i f f i c u l t i e s .
The o b j e c t i v e s of t h e demonstration d i s t i l l a t i o n of t h e i r r a d i a t e d YSRE f u e l c a r r i e r s a l t were:
(1)t o provide MSBR f u e l p r o c e s s i n g technology
w i t h a p r o c e s s t e s t e d w i t h fuel s a l t from an o p e r a t i n g r e a c t o r , ( 2 ) t o provide information ( n o t a v a i l a b l e from t h e l a b o r a t o r y i n v e s t i g a t i o n s ) on r e l a t i v e v o l a t i l i t i e s of f i s s i o n p r o d u c t s , and t o g i v e a g e n e r a l confirmation of p r e d i c t e d f i s s i o n product b e h a v i o r , and ( 3 ) t o uncover unexpected d i f f i c u l t i e s a s s o c i a t e d w i t h r a d i o a c t i v e o p e r a t i o n .
3 . w<;i.
.. ...
I n t h e n o n r a d i o a c t i v e t e s t s , s i x 48-liter batches of s a l t t h a t had t h e composition of t h e MSRE f u e l c a r r i e r salt and contained MdF
3
were
d i s t i l l e d a t condenser p r e s s u r e s below 0.1 t o r r " and a t a s t i l l - p o t temperature o f 1 8 0 0 ' ~ .
Whereas t h e s e t e s t s i n d i c a t e d areas i n which
f u r t h e r engineering development was r e q u i r e d , t h e y a l s o i n d i c a t e d t h a t decontamination from l a n t h a n i d e f l u o r i d e s by d i s t i l l a t i o n w a s f e a s i b l e . The s t i l l t h z t w a s used i n t h e n o n r a d i o a c t i v e t e s t s w a s a l s o used t o
distill t h e r a d i o a c t i v e salt ( c o n t a i n i n g no uranium) from t h e &ERE. T h i s o p e r a t i o n and i t s r e s u l t s a r e d e s c r i b e d i n t h e s e c t i o n s t h a t f o l l c w .
2
DESCRIPTION OF EQUPPMEhrE
2.1
Process Equipment
The equipment used i n t h e MSRE D i s t i l l a t i o n Experiment included a
48-liter f e e d t a n k c o n t a i n i n g a s a l t charge from the MSWE t c b e d i s t i l l e d , a 1 2 - l i t e r s t i l l from which t h e salt w a s v a p o r i z e d , a lO-in.-diam by condenser, and a 48-liter condensate r e c e i v e r .
?l-in.-long
This equrip-
rnent is only briefly described here; a more complete d e s c r i p t i o n i s g i v e n
elsewhere
3 e
The f e e d t a n k , shown i n F i g . 1, was a 9/2-in.-diam
by 2 6 - i n . - t a l l
r i g h t c i r c u l a r c y l i n d e r made from l/h-in.-thick H a s t e l l o y designed t o w i t h s t a n d an e x t e r n a l p r e s s u r e of
1 5 p s i a t 608'C.
It w a s The
condensate r e c e i v e r , shown i n ~ i g .2 , was a 16-in.-diam by 1 6 - ~ / 2 - i n . -
t a l l r i g h t c i r c u l a r c y l i n d e r having s i d e s of 1/4-in.-thick H a s t e l l o y K and a bottom of 3/8-in.-thick
B a s t e l l o y N.
an external p r e s s u r e of' 15 p s i at 6OQ"C.
*l t o r r i s 1/760 of a s t a n d a r d atmosphere.
It w a s designed t o w i t h s t a n d
T -g L Fig.
feed
tank.
c
0
1.
Molten
Salt
Distillation
Experiment.
Schematic
c
diagram
of
5
Fig. 2. Nolten Salt Distillation Experiment. the condensate receiver.
& .;.& . .
, .....
Schematic diagram of
The s t i l l and t h e condenser are shown i n F i g . 3.
The s t i l l pot
c o n s i s t e d o f an a n n u l a r volume between t h e vapor l i n e and t h e o u t l e t w a l l , and had a working volume of about 18 l i t e r s . t h e condenser were made of 3/8-in.-thick
Both t h e s t i l l and
B a s t e l l o y N and were designed
for p r e s s u r e s as low as 0.55 t o 1 . 5 t o r r .
The design temperature for
b o t h t h e still pot and t h e condenser w a s 982'C. The f e e d t a n k , t h e still p o t , t h e condenser, and t h e r e c e i v e r were mounted i n an angle i r o n frame t o f a c i l i t a t e t h e i r t r a n s f e r between BPdg. 3541, where t h e n o n r a d i o a c t i v e t e a t s were c a r r i e d
MSRE s i t e .
Q U ~ ,and
the
Since t h e equipment w a s t o be i n s t a l l e d i n a c e l l o n l y
s l i g h t l y l a r g e r t h a n t h e equipment frame, t h e thermocouples, t h e h e a t e r s , t h e i n s u l a t i o n , and most o f t h e p i p i n g were added b e f o r e t h e equipment
w a s placed i n t h e c e l l .
Ffgure
(without t h e i n s u l a t i o n ) .
4
i s a photograph cf t h i s equipment
A s t a i n l e s s s t e e l pan t o c a t c h molten s a l t
i n t h e event of a v e s s e l r u p t u r e w a s p l a c e d around t h e bottom o f t h e f ram.
Because l a r g e q u a n t i t i e s of i r o n and n i c k e l p a r t i c l e s were expected t o be p r e s e n t i n t h e f u e l s t o r a g e t a n k (FST) a t t h e MSWE (as a r e s u l t of t h e chemical processing of t h e f u e l s a l t ) , a porous metal f i l t e r w a s i n s t a l l e d i n t h e f e e d t a n k fill l i n e downstream from t h e freeze v d v e i n l i n e 112 (see Fig. 5 ) .
The I n ~ ~ n fei l t e r medium c o n s i s t e d o f ap-
proximately 28 i n . * of Huyck F e l t m e t a l FM
284
having a mean p o r e s i z e
of 45 p.
To prevent p a r t i c u l a t e s from reaching t h e vacuum p m p , F l a n d e r s High P u r i t y f i l t e r s were i n s t a l l e d i n t h e v a c w ~l i n e s from t h e f e e d t a n k and t h e r e c e i v e r .
These f i l t e r s were t e s t e d and d e n o n s t r a t e d t o
..>.. ..:..,. .. L . ! .. ,
. ...
VIEW A-A
-4
I t
the
Molten Salt Distillation Fig. 3. vacuum still and condenser.
Experiment.
Sehemati@
diagrm
of
8
c
Fig. 4. Molten-Salt Distillation Equipment Before Installation in Spare Cell at MSRE.
_i
-----e-c I ARGON SUPPLY
i
LEVEL
,
AND
u MEASUREMENT I
CONTROL
r-7
FEED TANK
Fig.
5.
Simplified
Flow
Diagram
L
CONDENSATE
of
MSRE Distillation
Experiment.
e f f e c t i v e l y remove
99.997% of 0. 3-LI p a r t i c l e s .
f i l t e r s can b e seen i n Fig.
4 on
The housings Tor t h e s e
two of t h e l a r g e r l i n e s a t t h e r i g h t -
hand s i d e .
All v a l v e s and p i p i n g t h a t d i d n o t c o n t a c t t h e molten salt were made o f s t a i n l e s s s t e e l and were housed i n a s e a l e d s t e e l c u b i c l e c o n t a i n i n g p r e s s u r e t r a n s m i t t e r s and two vacuum pmps- one t o evacuate t h e r e f e r e n c e s i d e of a d i f f e r e n t i a l p r e s s u r e t r a n s m i t t e r , and t h e o t h e r t o evacuate t h e d i s t i l l a t i o n process v e s s e l s .
The v a l v e box, w i t h i t s f r o n t and r e a r
cover p l a t e s removed, i s shown i n F i g .
6.
This box completed t h e second-
a r y containment around p i p i n g and i n s t r u m e n t a t i o n when i t s lower p l a t e s
were b o l t e d and s e a l e d i n p l a c e .
With t h e box w d e r a p r e s s u r e of 1 5 i n .
M 2 0, t h e l e a k r a t e w a s 0 . 1 c f h .
Ddring o p e r a t i o n , t h e p r e s s u r e i n t h e box
never exceeded 0 . 5 i n . H 0 , and t h e Peak r a t e was n e g l i g i b l e . 2
2 2 e
I n s t r m e n t a t ion
Measurement and Control of Temperature
2.2.1
Temperatures w e r e measured and c o n t r o l l e d over two r a n g e s :
500-606~~
f o r t h e f e e d t a n k and t h e condensate r e c e i v e r , and 800-1000QC f o r t h e
s t i l l and t h e condenser.
Platinum v s platinum
-
10% rhodium thermocouples
w e r e used f o r t h e high-temperature measurements, whereas l e s s expensive Chromel-Almel thermocouples were used on t h e f e e d t a n k s , condensate rec e i v e r , and salt t r a n s f e r l i n e s . w a s enclosed i n a 1/8-in.-diam
were used. the Pt
QS
Each of t h e thermocouples ( t o t a l ,
s t a i n l e s s s t e e l sheath; i n s u l a t e d Junctions
F i v e 12-point r e c o r d e r s were a v a i l a b l e f o r r e a d o u t :
~t
-
thermocouples.
60)
two f o r
10% R ~ thermocouples, L and t h r e e f o r t h e el-iromel-klumel
w.xw....
:... ..
..i/
.... . .. .... ,.. ... .. w&&-
l2
There were a t o t a l o f n i n e i n d i v i d u a l l y h e a t e d zones on t h e f e e d
tank, t h e s t i l l , t h e condenser, and t h e r e c e i v e r .
& ? .,.,;
The h e a t e r s for each
o f t h e s e zones were independently c o n t r o l l e d by a Pyrovane " ~ n - ~ f f 'con' t r o l l e r ; t h e v o l t a g e t o t h e h e a t e r s w a s c o n t r o l l e d by Variacs.
Heaters
on t h e v a r i o u s s a l t t r a n s f e r and argon Pines were nnanually c o n t r o l l e d by sron-offsr switches and Variacs
2.2.2
Measurement and Control o f P r e s s u r e P r e s s u r e measurements over t h r e e ranges were r e q u i r e d :
0 to
15 p s i a
f ~ monitoring r system pmpdown at t h e s t a r t of t h e r u n , f o r monitoring system r e p r e s s u r i z a t i o n a t t h e end of t h e run, and f o r c o n t r o l l i n g s a l t t r a n s f e r from t h e f u e l s t o r a g e t a n k ; 0 t o 10 t o r r f u r s u p p r e s s i n g vaporiz a t i o n w h i l e t h e s a l t w a s h e l d a t o p e r a t i n g temperature i n t h e s t i l l ; and 0 t o 1 t o r r during d i s t i l l a t i o n .
Absolute-pressure t r a n s d u c e r s (Foxboro D/P c e l l s w i t h one l e g evacuated) covering t h e 0- t o 1 5 - p i a range were used t o measure t h e p r e s s u r e i n t h e f e e d t a n k and i n t h e stiPP-condenser-receiver complex. p r e s s u r e measuring d e v i c e w i t h ranges of 0-0.083, 0-6.3,
An MMS Baratron
0-8.01, 0 - 0 . 0 3 ,
0-0.1,
0-1, 0-3, and 0-PO t o r r w a s used t o measure v e r y low p r e s s u r e s i n
t h e condensate r e c e i v e r The system pressure w a s c o n t r o l l e d i n t h e 0.1- t o 1 0 - t o m range by feeding argun t o t h e i n l e t of t h e vacuum p m p .
The B a r a t r s n u n i t produced
t h e s i g n a l r e q u i r e d f o r r e g u l a t i n g t h e argon flow. It w a s necessary t o ensure t h a t an e x c e s s i v e i n t e r n a l p r e s s u r e d i d n o t develop i n t h e system s i n c e , at o p e r a t i n g temperature, a p r e s s u r e i n excess of 2 a t m would have been u n s a f e .
T h i s was accomplished by u s i n g .
an absolute-pressure t r a n s m i t t e r i n t h e condenser off-gas l i n e t o monitor
..
13 ....># ..
. ...
:.:.I
L.
t h e system p r e s s u r e .
When t h e p r e s s u r e exceeded 15 p s i a , t h e argon
supply w a s s h u t off a u t o m a t i c a l l y .
2.2.3
Measurement and Control of Liquid Level The d i f f e r e n c e i n t h e p r e s s u r e a t t h e o u t l e t of a n argon-purged d i p
t u b e extending to t h e bottom of t h e v e s s e l and t h a t i n t h e gas space above t h e salt w a s used t o measure t h e depth of t h e s a l t i n b o t h t h e f e e d t a n k and t h e condensate r e c e i v e r . Two conductivity-type l e v e l probes were used i n t h e s t i l l for measuri n g and c o n t r o l l i n g t h e l i q u i d l e v e l .
These probes e s s e n t i a l l y measured
t h e total conductance between t h e m e t a l probes ( t h a t extended i n t o t h e molten s a l t ) and t h e wall of t h e s t i l l ; t h e t o t a l conductance was a funct i o n of t h e immersed s u r f a c e a r e a o f t h e probe. The c o n d u c t i v i t y probes ( s e e F i g .
7) were s i m i l a r t o t h e s i n g l e - p o i n ~
bevel probes t h a t were used i n t h e MERE d r a i n t a n k s .
T e s t s have shown
t h a t t h e range o f such an instrument i s l i m i t e d t o approximately 30% of t h e l e n g t h of t h e s i g n a l g e n e r a t i n g s e c t i o n .
A &in.
s e n s i n g probe w a s
used t o c o n t r o l t h e l f q u i e l e v e l between p o i n t s t h a t were 1 i n . and 3 i n . below t h e s t i l l - p o t overflow; a l o n g e r sensing probe w a s used t o measure v e r y low l e v e l s o f l i q u i d i n t h e s t L l 1 p o t . Metal d i s k s were welCed t o t h e c o n d u c t i v i t y probes t o a i d i n t h e i r calibration.
These d i s k s provided abrupt changes i n t h e i m e r s e d s u r f a c e
area o f each probe a t known l i q u i d l e v e l s .
During o p e r a t i o n , t h e s i g n a l
from a probe changed a b r u p t l y when t h e s a l t l e v e l reached one of t h e disks. The l i q u i d - l e v e l c o n t r o l l e r f o r t h e s t i l l p o t was a Foxboro Dynalog ,;.:........-j.
W ?
c i r c u l a r c h u t r e c o r d e r - c o n t r o l l e r , which c o n s i s t s o f a 1-kRz a6 bridge-type
14
TOP
VBEW
SIGNAL AMPLIFIER LEVEL INDICATO
HEA
COVER
FOLDED
EXCITATION SECTION
CONT.4lNMENT
AND
VESSEL
/
/SIGNAL
GENERATING
DISKS TQ CALIBRATION
Probe
Pig. for
9. Simplified Schematic of Still Pot in MSRE Distillation
SECTION
AIQ
Conductivity-Type Experiment.
Liquid
Level
measuring device using v a r i a b l e c a p a c i t a n c e for r e b a l a n c e .
The proper
c o n t r o l a c t i o n (see S e c t . 3 ) was accomplished by having a v a r i a b l e dead
zone imposed on t h e s e t - p o i n t adjustment mechanism.
With t h e c o n t r o l l e r
s e t f o r t h e d e s i r e d average l i q u i d l e v e l , t h e argon supply v a l v e t o t h e f e e d tali w a s opened when t h e l e v e l i n d i c a t o r dropped 3% below t h e s e t w a s c l o s e d when t h e l e v e l i n d i c a t o r r o s e 3% above t h e s e t p o i n t .
point
2.2.4
Radiation Instrumentation Ionization-chamber r a d i a t i o n monitors were mounted on p r o c e s s l i n e s
i n three locations:
one on t h e f i l t e r i n t h e f e e d t a n k v a c u m l i n e , one
on t h e f i l t e r i n t h e r e c e i v e r vacuum l i n e , and one on t h e l i q u i d - n i t r o g e n t r a p i n t h e receiver vacum l i n e .
The two monitors on t h e f i l t e r s were
s h i e l d e d from the r a d i a t i o n f i e l d in t h e cell by an 18-in.-thick
barytes
c o n c r e t e block w a l l and i n d i c a t e d t h e l e v e l of r a d i o a c t i v i t y f o r each filter.
The monitor on t h e l i q u i d - n i t r o g e n
trap w a s n o t s h i e l d e d from
t h e r a d i a t i o n f i e l d produced by t h e p r o c e s s vessels and t h u s registerec? t h e general l e v e l of r a d i a t i o n i n t h e c e l l .
Two Geiger-!48lPer
tubes
monitored t h e vacuum pumps.
which were a t t a c h e d t o t h e v a l v e box, They were s e t t o sound an alarm when t h e
r a d i a t i o n l e v e l reached 1 nR /hr a t a p o i n t about
2.2.5
6 i n . from t h e p u p s .
Instrument Panel The instrument p a n e l , from which t h e p r o c e s s w a s c o n t r o l l e d , con-
t a i n e d t h e temperature c o n t r o l l e r s , t h e p r e s s u r e and l e v e l r e c o r d e r s and c o n t r o l l e r s , t h e v a l v e o p e r a t i o n s w i t c h e s , t h e e l e c t r i c a l power supply c o n t r o l s , t h e temperature and p r e s s u r e a l u m s , and f o u r o f t h e f i v e temperatwe recorders.
T h i s p a n e l i s shown i n F i g . 8.
The f i f t h
16
w
"....,
17 temperature r e c o r d e r and t h e r a d i a t i o n measuring i n s t r u m e n t a t i o n w e r e mounted i n o t h e r c a b i n e t s .
2.3
Condensat e Sampler
The condensate sampler w%s t h e most important item of equipment f o r The s m p l e r w a s
o b t a i n i n g information from t h e d i s t i l l a t i o n experiment.
p a t t e r n e d a f t e r t h e equipment t h a t had p r e v i o u s l y been used t o add
233u
t o t h e f u e l d r a i n t a n k s and t o t a k e s a l t samples from t h e d r a i n t a n k s .
5
M o d i f i c a t i o n s o f t h i s design were made t o allow t h e s m p l e r t o be evacu a t e d t o a b u t 0.5 t o r r so t h a t condensate samples could b e w i t h d r a m without d i s t u r b i n g t h e o p e r a t i o n of t h e s t i l l . F i g u r e 9 shows a cutaway diagram of t h e sampler. o f t h e sampler were:
The main components
( I ) t h e containment v e s s e l i n which t h e samples
were s t o r e d ; ( 2 ) t h e t u r n t a b l e i n s i d e t h e containment v e s s e l , which
allowed t h e s m p l e c a p s u l e s t o be a l i g n e d w i t h t h e handling t o o l and a l s o w i t h t h e removal t o o l ; ( 3 ) t h e capsule handling t o o l , w i t h which empty c a p s u l e s were a t t a c h e d t o t h e c a b l e t o be lowered i n t o t h e sample r e s e r v o i r ; and
(4)
t h e r e e l assembly, w i t h which c a p s u l e s were lowered
and r a i s e d . The following sequence w a s used i n c o l l e c t i n g a condensate sample. With v a l v e HV-62 (see Fig. 9 ) c l o s e d and t h e containment v e s s e l a t
pheric
zl%mS-
p r e s s u r e , t h e sample handling t o o l w a s r a i s e d t o t h e h i g h e s t
position.
A s shown i n F i g . 9 , t h e c a b l e was a t t a c h e d about 2 0 i n . from
t h e t o p of t h e t o o l s o t h a t , when t h e c a b l e w a s r e e l e d t o t h e h i g h e s t p o s i t i o n , t h e t o p end of t h e t o o l p r o t r u d e d through v a l v e
W-66 and t h e
samples on t h e t u r n t a b l e could p a s s under t h e lower end of t h e t o o l .
BRML D W G 69-4945
Fig. 9. Experiment.
Cutaway Diagram of Condensate Sampler for MSRE Distillation
__...
....,........., , . ~ ... . ~
With t h e t o o l a t i t s h i g h e s t p o s i t i o n , an empty capsule was r o t a t e d underneath t h e Power end of t h e t o o l .
The t o o l was t h e n lowered onto
t h e s t e m o f t h e capsule and Pocked i n p l a c e by an adjustment a t t h e end of t h e t o o l p r o t r u d i n g through
Hv-66.
The t o o l and t h e a t t a c h e d c a p s u l e
were r a i s e d a g a i n , t h e t u r n t a b l e w a s r o t a t e d u n t i l t h e sampling notch w a s l o c a t e d underneath t h e t o o l , and t h e t o o l w a s lowered below v a l v e
KV-66.
Valve
W-66 w a s t h e n c l o s e d .
A t t h i s t i m e , t h e vacuum pump was
t u r n e d o n , and t h e containment v e s s e l w a s evacuated t o about 0 . 5 t o r r . When t h e p r e s s u r e i n t h e containment v e s s e l reached 0.5 t o r r , v a l v e IW-62
w a s opened and t h e sample handling t o o l and t h e empty c a p s u l e were lowe r e d u n t i l t h e sample capsule r e s t e d on t h e bottom of t h e sample r e s e r v o i r
at t h e end of t h e condenser.
The t o o l and capsule were t h e n r a i s e d above
valve IN-62, which w a s subsequently c l o s e d .
Next, t h e c o n t a i m e n t v e s s e l
w a s p r e s s u r i z e d t o atmospheric p r e s s u r e w i t h argon.
Valve PW-66 w a s
t h e n opened, and t h e sample handling t o o l w a s r a i s e d t o i t s h i g h e s t position.
F i n a l l y , t h e empty sample holder w a s r o t a t e d underneath t h e
sample handling t o o l , and t h e sample w a s lowered i n t o i t s h o l d e r and r e leased from t h e t o o l .
T h e process w a s repeated by raising t h e sample t o o l
a g a i n , r o t a t i n g another s m p l e capsule underneath i t , e t c . t u r n t a b l e w a s designed t o c o n t a i n 11 sample c a p s u l e s .
The
A f t e r t h e samples
had been c o l l e c t e d , t h e y were s t o r e d i n t h e containment v e s s e l .
A t the
end sf t h e experiment, t h e y were removed f o r a n a l y s i s .
A blower, which d r e w a i r i n t o t h e t o p of t h e l i n e a t t h e r e e l assemb l y to prevent r a d i o a c t i v e p a r t i c l e s f r o m escaping i n t o t h e o p e r a t i n g
area, w a s provided f o r t h e p a r t s of t h e o p e r a t i o n r e q u i r i n g IN-66 t o be ... ..i .........
.% . *e&
open. cell
e
The a i r handled by t h e blower w a s f i l t e r e d and exhausted i n t o t h e
20 The s m p l e capsules were s t a n d a r d 10-g MSRE sample c a p s u l e s s each of which w a s f i t t e d w i t h a key f o r a t t a c h i n g t o t h e sample handling t o o l .
The t h r e e w i r e r i b s on t h e s t e m
Figure 90 shows one of t h e s e c a p s u l e s .
e n s u e d t h a t t h e capsule would remain v e r t i c a l i n t h e c a p s u l e h o l d e r on the turntables F i g u r e 11 i s a photograph of t h e sampler during i n s t a l l a t i o n a t t h e
MSRE.
I n t h i s photograph, t h e unloading t u b e h a s been capped o f f , and
t h e t u r n t a b l e o p e r a t i n g handle i s not i n p l a c e .
The r i n g o f l e a d b r i c k s
around t h e sampler foms t h e base f o r t h e r a d i a t i o n s h i e l d , which i s f i t t e d over t h e containment v e s s e l .
2.4 Location of Equipment a t t h e MSRE The d i s t i l l a t i o n u n i t w a s i n s t a l l e d i n t h e s p a r e c e l l a t t h e MSRE
site; the s a p l e y
t h e v a l v e boxg and t h e instrument p a n e l were p l a c e d
i n t h e h i g h bay area above t h e c e l l .
F i g u r e 1 2 shows a schematic diagram
of t h e spare c e l l , while P i g . l 3 shows a photograph of t h e u n i t i n t h e c e l l b e f o r e t h e c e l l cover w a s put i n p l a c e .
3.
D E S C R I P T I O N OF DISTILLATION OPERATIOM
The t r a n s f e r of s a l t from t h e f u e l s t o r a g e t a n k (FST) t o t h e f e e d t a n k w a s i n i t i a t e d by evacuating t h e f e e d t a n k , which c o n t a i n e d about 2 l i t e r s o f u n i r r a d i a t e d s a l t , to about
1.5 psie.
Prior t o t h e t r a n s f e r ,
f r e e z e v a l v e FV-112, l o c a t e d between t h e FST and t h e f e e d t a n k f o r t h e s t i l l (see F i g . 5 )
w a s h e a t e d and opened.
( S a l t had p r e v i o u s l y been
f r o z e n i n t h e f e e d l i n e t o t h e s t i l l pot i n o r d e r t o i s o l a t e t h e f e e d
.............. .=,~
(D
P
d-
23
/LINE 8
(42
MOLTEN SALT FILTER I
I
Fig. 6 2 . South Elevation of MSN Spare Cell, Showing Distillation Unit and Sampler Locations.
.... ........ "'&w
(.i.-.
. . "i
24 ORNL
PHOTO 94840R
Fig. 13. Molten Salt S t i l l I n s t a l l e d in S p u e C e l l at MSRE.
t a n k from t h e c t h e r process v e s s e l s . )
A f t e r 12 l i t e r s o f s a l t had been
t r a n s f e r r e d fron t h e FST, t h e p r e s s u r e of t h e f e e d t a n k i n c r e a s e d from
4 psi% t o
about
atmospheric p r e s s u r e over a p e r i o d o f about 2 m i n ; t h i s
i c d i c a t e d t h z t gas w a s being t r a n s f e r r e d from t h e f e e d t a n k through $he
s a l t charging l i n e .
More s a l t could n o t b e t r a n s f e r r e d from t h e FST even
though t h e bubbler i n t h e FST i n d i c a t e d t h s t a d d i t i o n a l s e l t w a s p r e s e n t . Only one f u r t h e r attempt a t s a l t t r a n s f e r was made because o f t h e p o t e n t i a l danger o f blowing t h e t r a p p e d s a l t o u t of t h e f r e e z e v a l v e ; t h i s would have made it impossible t o o b t e i n a s e a l between t h e f e e d t a n k and t h e f u e l storage tank.
A f t e r we had e s t a b l i s h e d t h a t
EL
t i g h t s e a l could be
made, we decided t o proceed w i t h t h e experiment u s i n g t h e s a l t a l r e a d y t r a n s f e r r e d , even though i t s volwne w a s much l e s s t h a n t h e a n t i c i p a t e d volume
(48 l i t e r s ) .
TO start t h e d i s t i l l a t i o n experiment, t h e s t i l l - p o t
Feed l i n e was
thawed, a l l p r o c e s s v e s s e l s were evacuated t o 5 t o r r , and t h e s t i l l pot
w a s h e a t e d t o gSOQC.
The v a l v e between t h e f e e d t a n k and t h e v a c u m p m p
w a s t h e n c l o s e d , and argon w a s i n t r o d u c e d i n t o t h e f e e d t a n k t o i n c r e a s e t h e p r e s s u r e to about 0 . 5 a t m ; this f o r c e d the s a l t t o f l o w f r o m t h e feed
t a n k into t h e s t i l l p o t .
When 7 l i t e r s of s a l t had been t r a n s f e r r e d t o
t h e still p o t , t h e condenser p r e s s u r e w a s reduced t o 0.2 torr t o start the d i s t i l l a t i o n of salt.
A t t h i s point, control of t h e l i q u i d level i n
t h e s t i l l p o t w a s switched t o t h e automatic mode.
I n t h i s mode, s a l t w a s
f e d t o t h e s t i l l p o t a t a ate s l i g h t l y g r e a t e r t h a n t h e v a p o r i z a t i o n r a t e . The argon f e e d valve t o t h e f e e d t a n k remained open ( f o r c i n g more s a l t i n t o t h e s t i l l p o t ) u n t i l t h e l i q u i d l e v e l i n t h e s t i l l rose t~ a given .... .(..... .;&,>.....
s e t p o i n t ; t h e v a l v e t h e n c l o s e d and remained c l o s e d u n t i l t h e l i q u i d
26
l e v e l decreased t o a second s e t p o i n t .
I n t h i s manner, t h e s a l t volume
i n t h e s t i l l p o t w a s maintained n e a r 7 l i t e r s . A s t h e s a l t vapor passed through t h e condenser, h e z t w a s removed
from it by conduction through t h e condenser walls and t h e i n s u l a t i c n and by convection t o t h e a i r i n t h e cell.
The condenser was d i v i d e d i n t o
t h r e e h e a t e d zones, t h e temperatures of which could be c o n t r o l l e d separ a t e l y when condensation w a s n o t o c c u r r i n g .
A s h a r p i n c r e a s e i n tempera-
t u r e above t h e s e t p o i n t s n e a r t h e condenser e n t r a n c e , as w e l l as a g r a d u a l temperature r i s e n e a r t h e end of t h e condenser, accompanied t h e beginning of d i s t i l l a t i o n .
Operation of h e a t e r s t o keep t h e t e m p e r a t m e
of t h e condenser above t h e l i q u i d u s t e n p e r a t m e o f t h e condensate w a s not necessary d u r i n g vapor condensation.
I n t h i s psrt o f t h e r u n , the still-
p o t temperature w a s slowly i n c r e a s i n g ; and, s i n c e t h e c o n c e n t r a t i o n s o f v o l a t i l e BeF
2
and ZrF
4 were
s t i l l f a i r l y high, t h e vaporization r a t e w a s
An abnoz-malby h i g h temperature a t t h e end o f t h e con-
also increasing.
denser i n d i c a t e d t h a t t h e c a p a c i t y o f t h e condenser would be exceeded. By r a i s i n g t h e Condenser p r e s s u r e to 0.8 t o r r , t h e d i s t i l l a t i o n r a t e w a s reduced s u f f i c i e n t l y t o m a i n t a i n t h e condenser temperature n e a r 700QC, an a c c e p t a b l y low temperature. When t h e c o n t e n t s o f t h e feed t a n k ( 7 l i t e r s ) had been d e p l e t e d , t h e
salt i n t h e s t i l l feed l i n e w a s frozen; then a t o t a l of
4 of
o f s a l t i n t h e s t i l l p o t w a s d i s t i l l e d by b a t c h d i s t i l l z k i s n .
the 7 l i t e r s A t this
p o i n t , t h e s t i l l - p o t temperature w a s 980QC. As t h e more v o l a t i l e mate-
~ i a l swere vaporized from t h e s t i l l p o t , t h e condenser pressure w a s reduced from 0.8 t o r r t o 0 . 1 t o r r i n o r d e r t o m a i n t a i n a f a i r l y h i g h distillation rate
a
When t h e condenser p r e s s u r e could n o t be decreased
.. .. ,_... ,... w .. ~
: . i
f u r t h e r , t h e d i s t i l l a t i o n o p e r a t i o n w a s t e r m i n a t e d by i n c r e a s i n g t h e p r e s s u r e i n a l l t h e process v e s s e l s to atmospheric pressure and t u r n i n g o f f t h e power t o a l l t h e h e a t e r s .
The semicontinuous d i s t i l l a t i o n phase l a s t e d f o r 9.3 hr; the average d i s t i l l a t i o n r a t e during t h i s p e r i o d w a s 0.57 l i t e r j h r .
The d u r a t i o n of
t h e b a t c h d i s t i l l a t i o n p e r i o d w a s 13.8 h r ; t h e average d i s t i l l a t i o c r a t e
f o r t h i s p e r i o d w a s 0.36 l i t e r / h r .
Eleven condensate samples were taken
during t h e run at approximately 90-min i n t e r v a l s .
A t t h e end o f t h e
experiment, r a d i a t i o n r e a d i n g s o f t h e s e smples ranged from c o n t a c t ( t h e f i r s t sample) t o 5QQ
4 R/hr a t
at contact ( t h e last s m p l e ) .
After t h e s t i l l had been allowed t o c o o l down, a l l e l e c t r i c a l and thermocouple l e a d s t o t h e s t i l l were c u t and a l l p n e u m k i c instrument Pines f r ~ mt h e v a l v e box were disconnected.
The sampler w a s dismantled
and s e n t t o t h e b u r i a l ground; t h e p r o j e c t i n g end of t h e s m p l e l i n e w a s flanged.
Valve handle e x t e n s i o n s were c u t f l u s h w i t h t h e f l o o r o f t h e
h i g h b8y sea.
The process v e s s e l s and t h e valve box were allowed to
remain i n piece.
4. 4.1
EXPERIMENTAL RESULTS
S m a r y of Experimental Data
I n o r d e r t o determine t h e c a p a b i l i t y o f t h e d i s t i l l a t i o n equipment f o r s e p a r a t i n g f i s s i o n products from t h e c a r r i e r s a l t , w e measured t h e f o l l o w i n g q u a n t i t i e s i n t h e course of t h i s experiment: of .... .. ,.. ;,. ....: ;
.@w
8.11
t h e concentration
t h e major and most of t h e minor components i n t h e f e e d s a l t t o t h e
s t i P P , $the c o n c e n t r a t i o n of each component i n t h e condensate as it l e f t
28 t h e s t i l l p o t , t h e volume of l i q u i d f e d t o t h e s t i l l p o t , and t h e volume
of' l i q u i d c o l l e c t e d i n t h e r e c e i v e r .
~. .& .....?
An e s t i m a t e 7 w a s made of t h e con-
c e n t r a t i o n o f each f i s s i o n product whose c o n c e n t r a t i o n i n t h e f e e d s a l t
The estimate w a s based on t h e production r a t e o f each
was not measured.
f i s s i o n product i n t h e MSRE and assumed that a l l t h e p r e c u r s o r s o f a given f i s s i o n product remained i n t h e s a l t .
This seemed t o b e a f a i r l y
good assumption f o r i s o t o p e s having no long-lived gaseous p r e c u r s o r s .
All t h e Concentrations were converted t o mole f r a c t i o n s ; t h e m o l e f r a c t i o n s of r a d i o a c t i v e m a t e r i a l s were c a l c u l s t e d as of May 7 , 1969. The volumes were determined by measuring t h e weight of l i q u i d over t h e end o f a b u b b l e r , d i v i d i n g by a s a l t d e n s i t y o f 2.2 g / m 3 t o o b t a i n t h e depth o f l i q u i d , and m u l t i p l y i n g t h i s v a l u e by t h e c r o s s - s e c t i o n a l area of t h e p a r t i c d a r vessel t o o b t a i n t h e volume.
We assumed t h a t t h e mass
d e n s i t y of t h e l i q u i d w a s independent of c a n p o s i t i o n and t h a t t h e volume
of l i q u i d i n t h e s t i l l pot could b e c a l c u l a t e d by s u b t r a c t i n g t h e volnne of condensate c o l l e c t e d from t h e t o t a l volume of s a l t f e d to t h e s t i l l from t h e f e e d t a n k . E
Assuming t h a t molar volumes can be added (which i s
f a i r l y gooti assumption f o r f l u o r i d e s a l t s ) , we c a l c u l a t e d m a s s d e n s i t i e s
f o r liquids i n t h e c o n c e c t r a t i o n range seen i n t h i s experiment and found o n l y a 5% v a r i a t i o n ; hence, o u r assumption o f c o n s t a n t d e n s i t y appears
t o be acceptable.
The a n a l y s e s of a l l t h e condensate samples are r e p o r t e d
i n t h e kppendix.
4.2
M a t e r i d Balance C a l c u l a t i o n s
One of t h e most concise ways t o express t h e s e p a r a t i o n performance of t h e d i s t i l l a t i o n equipment i s to convert t h e condensate a n a l y s e s t o e f f e c t i v e
&.&",
â&#x20AC;&#x2DC;-
r e l a t i v e v o l a t i l i t i e s w i t h r e s p e c t t o LiF.
The e f f e c t i v e r e l a t i v e
v o l a t i l i t y of component i w i t h r e s p e c t t o LiF i s d e f i n e d a s :
a i-LiF
= yLiP /xLiF
9
v h e r e y = mole f r a c t i o n i n t h e condensates
x = mole f r a c t i o n i n t h e s t i l l p o t . Although t h e composition of each component i n t h e still pot w a s not neasu r e d d i r e e t l y during t h e r u n , t h e d a t a allowed t h e composition of t h e s t i l l p o t t o b e e s t i m a t e d from a mzterial balance f o r each component.
I n t h i s s e c t i o n , w e d e r i v e t h e material balance equations and o u t l i n e t h e c a l c u l a t i o n a l procedure.
For t h e s e m i c o n t i n u ~ u snode of o p e r a t i o n , a d i f f e r e n t i a l mole b a l a n c e f o r component i g i v e s :
where
I = t o t a l moles f e d t o t h e still p o t , 0 = t c t a l moles removed f r o m the s t i l l p o t ,
Mi fi
yi
= moles of component i i n t h e still p o t , = mole f r a c t i o n o f component i i n t h e f e e d , = mole f r a e t i o n of component i i n t h e condensate.
Since volume w a s t h e measured q u a n t i t y , we can make t h e following substitutions:
.. ... .... ......
.wiw
Vin
where
= volume of' s a l t Ped t o t h e s t i l l p o t , l i t e r s , = v d m e of condensate c o l l e c t e d $l i t e r s
v
j
= p a r t i a l moEar volume" of component j, l i t e r s / m o k .
When w e s u b s t i t u t e t h e q u a n t i t i e s i n Eq. ( 3 ) i n t o Eq. (21, we o b t a i n :
Y,
f,
f;
bJ
v in -
f .v j -1 J j
where t h e c o n d i t i o n s V were used.
in
=
vout
= Mi = 0 a t t h e s t a r t o f t h e experiment
The composition i n t h e s t i l l p o t can be determined by s o l v i n g
f o r Ne f o r each component. 1
vout
This equation i s v a l i d up t o t h e p o i n t where
= 7.07 l i t e r s ( t h e ecd o f t h e semicontinuous d i s t i l l a t i o n ) . Sf M. moles of component i are p r e s e n t i n t h e s t i l l p o t and dbl P i
moles of component i are vaporized during t h e b a t c h d i s t i l l a t i o n , t h e mole f r a c t i o n o f component i i n t h e vapor i s given by
yi = N k-l
9
%
"Assumed t o be independent of t h e cornposition o f t h e l i q u i d .
= ......;'
.
'.I:-
.
;
s i m i l a r l y , f o r component j ( i
From E q s . ( 6 ) and
(91, w e
+ j),
o b t a i n t h e expression
Assuming t h a t t h e p a r t i a l molar volumes v
i
are independent of t h e c o n p ~ ~ i -
t i s n of t h e l i q u i d (as b e f o r e ) , w e multiply b o t h s i d e s sf Eq. ( 9 ) by vi and sum both s i d e s over all i to o b t a i n t h e following e q u a t i o n :
where
V s t i l l = volume of s a l t i n t h e still pot, l i t e r s .
I. Sslving ~ q .(1.0)f o r CM
I n t e g r a t i n g Eq.
9
yields:
(11)y i e l d s : ~
Vstill Y.
d V s t i i l9
N . . . .
............ c "+ ..wp.
li
i=l
I
I
32
where %a
jo
= moles o f component j p r e s e n t i n t h e s t i l l p o t a t t h e s t a r t
,.:.w.>. ......,.
of t h e batch d i s t i l l a t i o n , V
6
= volume of s a l t i n s t i l l p o t at start of b a t c h d i s t i l l a t i o n .
The q u a n t i t y M
jo
t h e v a l u e s of
vin
distillation. liters
i n Eq. ( 6 2 ) i s c a l c u l a t e d by e v a l u a t i n g Eq. (51, u s i n g
m a vo u t
ana
vout
t h a t correspond t o t h e end of t h e senicontinuous
( A t t h e end of semicontinuous d i s t i l l a t i o n , Vin = 5.07 l i t e r s . )
TIE
=
13.8
composition of t h e s t i l l pot i s
determined by e v a l u a t i n g Eq. ( 1 2 ) f o r each component t h a t i s p r e s e n t . The i n t e g r a l s i n E q s .
( 5 ) and ( 1 2 ) were e v a l u a t e d by p l o t t i n g Y.
v s t h e volume of condensate c o l l e c t e d i n t h e r e c e i v e r during t h e senzicontinuous d i s t i l l a t i o n and
vs the s t i l l - p o t volume ( c a l c u l a t e d as explained p r e v i o u s l y ) dcring t h e b a t c h d i s t i l l a t i o n , f i t t i n g t h e r e s u l t i n g curves t o simple e m p i r i c a l f u n c t i o n s of t h e a p p r o p r i a t e volume, and t h e n i n t e g r a t i n g t h e s e equations
F o r any component, a f a i r l y wide range of e q u a t i o n parameters f i t t h e s c a t t e r e d d a t a e q u a l l y w e l l ; howevers t h e v a l u e s sf t h e i n t e g r a l s were not s i g n i f i c a n t l y s e n s i t i v e t o t h e s e v a r i a t i o n s i n t h e parameters. The N Tuâ&#x20AC;&#x2122; f.v . were adequately r e p r e s e n t e d by c o n s i d e r i n g only sums r y i v i and 1 1 i=l t h e major s8lt components EiF, BeF2$ and ZrF4 s i n c e t h e mole f r a c t i o n s
e
3% of t h e f i s s i o n p r o d u c t s were n e g l i g i b l e as compared w i t h t h e mole f r a c t i o n s of t h e s e components. Using Eqs. ( 5 ) and (121,we c a l c u l a t e d the number of moles o f each component p r e s e n t i n t h e s t i l l p o t a t t h e t i m e each condensate sample was taken,
The mole f r a c t i o n of each component i n t h e s t i l l pot a t t h a t t i m e
w a s c a l c u l a t e d u s i n g t h e following equation:
The measured v a l u e s o f yi and t h e c 8 l c u l a t e d v a l u e s of x. were t h e n used 1
i n Eq.
(1) t o c a l c u l a t e t h e r e l a t i v e v o l a t i l i t y of each component, w i t h
r e s p e c t t o EiF, f o r each sample.
4.3
R e s u l t s of Relative ~ o l a t i l i t yC a l c u l a t i o n s
The e f f e c t i v e r e l a t i v e v o l a t i l i t i e s
mafor s a l t components, B ~ Fana z 2
w i t h r e s p e c t t o LiF
of t h e
~ ana F of~ the ~ f i s s i o n products 9 % ~ ~
o f t h e d i s t i l l a t i o n o p e r a t i o n , as o b t a i n e d from t h e c a l c u l a t i o n s , a r e g i v e n i n F i g s . 14-17.
I n t h e s e f i g u r e s , t h e most s e l f - c o n s i s t e n t v a l u e s
r e s u l t e d when t h e c a r r i e r s a l t composition i n t h e f e e d was assumed -to b e
65-30-9 mole % LiP-BeF2-ZrF4 r a t h e r t h a n t h e s l i g h t l y d i f f e r e n t composit i o n i n d i c a t e d by t h e a n a l y s i s of t h e s a l t from the f u e l s t o s
The d i f f e r e n c e between t h e a n a l y t i c a l v a l u e s and t h e v a l u e s a c t u a l l y ....<,w<pp ........:i
used c a n probably b e a t t r i b u t e d t o z i r c o n i m metal, which was p r e s e n t in
34
~.
%,..... ....... "
LlTEWS CONDEF6SATE COLLECTED
LITERS CONDENSATE COLLECTED
37 ..... .,.,. ..... ..,by
0
2
3
4
5
6
a
8
LITERS CONDENSATE COLLECTED
F i g . 17. E f f e c t i v e R e l a t i v e V o l a t i l i t y of l a 7 C s , Varying t h e AS SUE^ ~ e e dC o n c e n t r a t i o n of 1 3 7 ~ s .
Showing E f f e c t of
t h e f u e l s t o r a g e tank a t t h e t i m e t h e a n a l y s i s w a s made b u t w a s f i l t e r e d
'v
o u t when 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 s t i l l f e e d t a n k . The e f f e c t i v e r e l a t i v e v o l a t i l i t i e s of BeF2' ZrF4, and 95Zr are
shorn i n F i g . 1 4 .
The e f f e c t i v e r e l a t i v e v o l a t i l i t y of BeF
w a s essen-
2
t i a l l y constanat during t h e r u n , e x h i b i t i n g an average v a l u e o f 3.8.
This
v a l u e a g r e e s f a v o r a b l y w i t h t h e v a l u e of 3.9 measured by Smith, F e r r i s , and Thompson* b u t i s s l i g h t l y lower t h a n t h e v a l u e of
4.7 measured
by
S l i g h t i n a c c u r a c i e s i n c a l c u l a t i o n s (especially
Hightower and McNeese
t h e material b a l a n c e c a l c u l a t i o n s d e s c r i b e d e a r l i e r ) and a n a l y s e s probably account f o r such d i f f e r e n c e s . he e f f e c t i v e r e l a t i v e v o l a t i l i t i e s o f f i s s i o n product
9 5 ~ rand of
ZrF4, t h e c a r r i e r s a l t c o n s t i t u e n t , a r e i n agreement w i t h r e s p e c t t o
magnitude and v a r i a t i o n during t h e r u n .
When t h e a n a l y s i s of t h e s a l t
i n t h e FST w a s used i n t h e r e l a t i v e v o l a t i l i t y c a l c u l a t i o n , t h e r e s u l t i n g r e l a t i v e v o l a t i l i t i e s of t h e ZrF v a l u e s f o r "ZrS value n e a r
4
Figure
4 were
about a f a c t o r o f 2 lower t h a n t h e
1 4 shows t h a t a ZrFb -Lip decreased from an i n i t i a l
a t t h e s t a r t sf t h e run t o about l a t t h e end of t h e r u n .
These v a l u e s b r a c k e t t h e v a l u e ( 2 . 2 ) measured by Smith e t a l . mixtures having a ZrF
4
L
i n salt
c o n c e n t r a t i o n about 2% of t h a t i n t h i s system.
The e f f e c t i v e r e l a t i v e v o l a t i l i t i e s o f t h e l a n t h a n i d e f i s s i o n products '44Ce:,
l4'Prn,
and 155Eu a r e shown i n F i g .
v o l a t i l i t y of 144Ce
r o s e s h a r p l y from
-2
sample t o about 1.0 x 1 0 quent samples.
15. The e f f e c t i v e r e l a t i v e
6.1 x 1 0-4 a t t h e
t i m e of the f i r s t
where it remained f o r n e a r l y a l l t h e subse-
However, t h e r e l a t i v e v o l a t i l i t y f o r t h e f i f t h sample
w a s lower t h a n 1 . 0 x
lo-'
by a factor of 3.
The IGW i n i t i a l value w a s
1 . 5 t o 3.4 t i m e s the v a l u e measured i n an e q u i l i b r i u m s t i l l , whereas t h e
. .. ... ....:...x;;...y % ..
39 h i g h , s t e a d y v a l u e w a s 24 t o
56 t i m e s
t h e v a l u e measured i n t h e
equilibrium s t i l l . The e f f e c t i v e r e l a t i v e v o l a t i l i t y
0%
147,
w a s based on a computed
f e e d c o n c e n t r a t i o n , which w a s considered t o be a more a c c u r a t e v a l u e t h a n t h e measured f e e d c o n c e n t r a t i o n s i n c e measured c o n c e n t r a t i o n s of o t h e r l a n t h a n i d e f i s s i o n p r o d u c t s had agreed w e l l w i t h computed concen$rations
A s i n t h e case of
144Ce, t h e r e l a t i v e v o l a t i l i t y of L47h was
low a t t h e t i m e t h e f i r s t sample w a s t a k e n , t h a t i s , l e s s t h a n 7.8 x
4
10- ; it r o s e s h a r p l y to about 3.4 x POm3 f o r t h e remaining samples except f o r t h e f i f t h sample, which w a s low.
There were no previo-Jsly
measured v a l u e s f o r t h e r e l a t i v e v o l a t i l i t y of promethium w i t h which t h e s e r e s u l t s could be compared.
At t h i s p o i n t , it i s i n t e r e s t i n g t o note t h a t , when t h e e f f e c t i v e w a s c d c u l a t e d on t h e b a s i s of t h e measured r e l a t i v e v o l a t i l i t y of 147h c o n c e n t r a t i o n o f l4’Rn tisn, the
ci
1 4 7 h - L iP
i n t h e FST i n s t e a d of on an e s t i m a t e d concentra-
f o r each sample, except t h e f i r s t , n e a r l y coincided
w i t h t h e r e s p e c t i v e c a l c u l a t e d p o i n t fsr 144Cee T h e v a r i a t i o n sf t h e r e l a t i v e v o l a t i l i t i e s of 155Eu d u r i n g t h e run
c l o s e l y p a r a l l e l e d t h e v a r i a t i o n s observed f o r 144Ce and 147F’m. t h e v a l u e f o r t h e f i r s t sample w a s low ( l e s s t h a n
Although
1.5 x 10-5), t h e v a l u e s
f o r a l l subsequent samples, except t h e f i f t h , were much h i g h e r , th8.t i s ,
-4
about 2.2 x 10
a f a c t o r of 2.6. (which
.
The v a l u e f o r t h e f i f t h sample was lower t h a n t h i s by These c a l c u l a t e d e f f e c t i v e r e l a t i v e V Q h t i l i t i e S
were based on a computed f e e d c o n c e n t r a t i o n of 155Eu) were lower
t h a n t h e v a l u e of 1.1 x ...
....,.,.,. :........ ...&W . .
:l
measured i n r e c i r c u l a t i n g e q u i l i b r i u m s t i l l s .
However, t h e accuracy of t h e ’55Eu v a l u e s i s q u e s t i o n a b l e s i n c e some
40 d i f f i c u l t y w a s experienced i n making t h e analgrses; a l l o f Zhe r e s u l t s for "bu
i n t h e condensate samples were r e p o r t e d a s approximate (see On t h e o t h e r hand, it i s s i g n i f i c a n t t h a t t h e v a r i a t i o n
t h e Appendix). Of
during t h e run c l o s e l y p a r a l l e l e d t h e r e l a t i v e v o l a t i l i t i e s
%5rn,LiF
of 144,e
and
Figure
147pm. 16
shows t h e e f f e c t i v e r e l a t i v e v o l a t i l i t i e s of 91Y and "Sr.
During t h e r u n , t h e e f f e c t i v e r e l a t i v e v o l a t i l i t y of 91Y had an average v a l u e of
1.4 x
about 410 t i m e s t h e v a l u e measured i n r e c i r c u l a t i n g The v a r i a t i o n of agl
equilibrium s t i l l s .
Y-LiF
during t h e r u n w a s s i m i l a r
t o v a r i a t i o n s of r e l a t i v e v o l a t i l i t i e s o f t h e l a n t h a n i d e s ; t h e low v a l u e f o r t h e f i f t h smphe w a s most n o t i c e a b l e . The e f f e c t i v e r e l a t i v e v o l a t i l i t y of "Sy.
(based on t h e measured
c o n c e n t r a t i o n i n t h e f e e d ) had an average value during t h e run of 10-39 about
stills.
84 times
t h e v a l u e measured i n r e c f r c u l a t i n g e q u i l i b r i u m
Although not shown i n F i g .
v o l a t i l i t y o f "Sr
4.1 x
16, t h e average v a l u e o f t h e r e l a t i v e
(based on a computed Concentration i n t h e f e e d ) w a s
0.193, about 3900 times t h e v a l u e measured i n e q u i l i b r i u m s t i l l s .
The
r a t i o o f t h e 89Sr a c t i v i t y t o t h e 90Sr a c t i v i t y i n t h e condensate samples v a r i e d from 0.22 t o v a l u e s g r e a t e r t h a n 1 0 .
It should have been about
0.002 f o r each sample o r , a t t h e l e a s t , should have remained c o n s t a n t . C a l c u l a t i o n s of t h e e f f e c t i v e r e l a t i v e v o l a t i l i t y of "7,s
were
based on an e s t i m a t e d f e e d c o n c e n t r a t i o n s i n c e t h e c o n c e n t r a t i o n of 137Cs
i n t h e f e e d s a l t w a s n o t measured.
long-lived gaseous p r e c u r s o r (147Xe t h e a c t u a l c o n c e n t r a t i o n of 137C!s
However, 137Cs has a f a i r l y
h a l f - l i f e = 3.9 min) t h a t causes
i n t h e s a l t t o be l e s s t h a n t h a t pre-
d i c t e d when t h e method o u t l i n e d e a r l i e r i s used.
Also, because t h e
41 ... .;.... " .........: .;.. U & ,
a c t u a l r e l a t i v e v o l a t i l i t y of CsF i s fairly h i g h , t h e r e s u l t s of c a l c u l a t i o n s o f t h e e f f e c t i v e r e l a t i v e v o l a t i l i t y are s e n s i t i v e t o t h e assumed feed c o n c e n t r a t i o n of 137Cs.
Figure
1 7 shows c a l c u l a t e d r e l a -
t i v e v o l a t i l i t i e s . of " 7 ~ s f o r two assumed feed c o n c e n t r a t i o n s .
0
e he
p o i n t s around t h e lower curve r e s u l t f r o m t h e f e e d c o n c e n t r a t i o n of
sC'"
which would apply i f a l l t h e p r e c u r s o r s remained i n t h e s a l t These p o i n t s r e p r e s e n t lower l i m i t s f o r t h e
d u r i n g MSRE o p e r a t i o n .
e f f e c t i v e r e l a t i v e v o l a t i l i t y i n t h i s d i s t i l l a t i o n ; t h e p o i n t s around t h e upper l i n e r e s u l t from a feed c o n c e n t r a t i o n j u s t h i g h enough t o keep t h e computed c o n c e n t r a t i o n of '37,s
i n t h e s t i l l - p o t l i q u i d from falling
t o zero o r below, and r e p r e s e n t upper l i m i t s f o r t h e e f f e c t i v e r e l a t i v e volatility
0%"13',s.
he h i g h e s t e f f e c t i v e r e l a t i v e v s l E t i l i t y of
la7cs
seen i n t h e s e c a l c u l a t i o n s was o n l y about 20% o f t h e v a l u e measured by ,Smith e t a l . i n LiP-BeF
2
systems.
A s seen from t h e previous c a l c u l a t e d r e s u l t s , a l l components except b e r y l l i u m and zirconium had e f f e c t i v e r e l a t i v e v o l a t i l i t i e s t h a t d i f f e r e d
(in some c a s e s , d r a s t i c a l l y ) from v a l u e s p r e d i c t e d f r o m work w i t h equilibrium systems.
Some possible explanations for these discrepancies are
d i s c u s s e d i n t h e following s e c t i o n .
4.4
P o s s i b l e Explanations o f C a l c u l a t e d R e s u l t s
P o s s i b l e causes f o r t h e d i s c r e p a n c i e s between t h e e f f e c t i v e r e l a t i v e v o l a t i l i t i e s of some of t h e f i s s i o n p r o d u c t s i n t h i s experiment and v a l u e s measured p r e v i o u s l y i n c l u d e :
(1) entrainment of d r o p l e t s of s t i l l - p o t
P i q u i d i n t h e vapors ( 2 ) c o n c e n t r a t i o n g r a d i e n t s i n t h e s t i l l p o t , ,.@
.. ...
ii..
...
( 3 ) contamination o f samples during t h e i r p r e p a r a t i o n f o r radiochemical a n a l y s i s , and ( 4 ) i n a c c u r a t e a n a l y s e s .
These p o s s i b i l i t i e s a r e d i s c u s s e d
below. P
4.4.1
Entrainment of D r o p l e t s of 8 t i l l - P o t L i a s Entrainment r a t e s of o n l y 0.023 mole of l i q u i d p e r mole of vapor,
o r l e s s , would account f o r t h e high r e l a t i v e v o l a t i l i t i e s c a l c u l a t e d f o r t h e s l i g h t l y v o l a t i l e f i s s i o n p r o d u c t s 1 4 4 ~ e , 147,
, 9lY,
and 9OSr.
Rates of t h i s o r d e r would not b e r e f l e c t e d i n t h e e f f e c t i v e r e l a t i v e v o l a t i l i t i e s of r e l a t i v e l y v o l a t i l e m a t e r i a l ( a 2 1).
he h i g h c o r r e l a -
t i o n of t h e s c a t t e r of t h e c a l c u l a t e d e f f e c t i v e r e l a t i v e v o l a t i l i t i e s of d i f f e r e n t slightly v o l a t i l e f i s s i o n p r o d u c t s i s c o n s i s t e n t w i t h t h e h y p o t h e s i s t h a t entrainment o c c u r r e d . Although t h e r e w a s some evidence of entrainment d u r i n g t h e nonr a d i o a c t i v e o p e r a t i o n of t h e s t i l l ,
4 t h e c o n s i d e r a b l y lower r a t e of
d i s t i l l a t i o n o f t h e MSRE s a l t m k e s entrainment by t h e same mechanism less likely.
T h e r e f o r e , some o t h e r reason f o r entrainment i n t h e r a d i o -
a c t i v e o p e r a t i o n should be sought.
Evidence of a s a l t m i s t above t h e
s a l t i n t h e pump bowl a t t h e ,KRE and a l s o above s a l t samples removed
from t h e MSWE has been r e p ~ r t e d ; ~ â&#x20AC;?t h e s t u d i e s have i n d i c a t e d t h a t t h e s e m i s t s a r e p r e s e n t over r a d i o a c t i v e s a l t m i x t u r e s b u t not over nonradioactive mixtures.
According t o t h e r e p o r t e d d a t a , e i t h e r a m i s t
c o n c e n t r a t i o n (grams of s a l t p e r em3 of g a s ) or a r a t e of formation of
m i s t (grams of s a l t p e r second) could be c a l c u l a t e d .
Entrainment r a t e s
s u f f i c i e n t l y l a r g e t o e x p l a i n t h e r e s u l t s of t h i s experiment could only be o b t a i n e d by assuming t h a t t h e g a s space above t h e s a l t c o n t a i n e d s a l t
m i s t having t h e same c o n c e n t r a t i o n as t h a t seen i n t h e s t u d i e s , i n s t e a d
43 of by assuming equal m i s t formation r a t e s .
However, t h e c o n c e n t r a t i o n s
c a l c u l a t e d from t h e d a t a were s c a r c e l y adequate t o e x p l a i n t h e e n t r a i n e d f r a c t i o n t h a t must have occurred.
Furthermore, b o t h t h e m i s t formation
r a t e and t h e c o n c e n t r a t i o n o f t h e m i s t would be expected to decrease w i t h decreasing decay power d e n s i t y i n t h e l i q u i d .
Since t h e s a l t used
i n t h e d i s t i l l a t i o n experiment had a much lower decay power d e n s i t y t h a n t h e s a l t e x m i n e d f o r m i s t formation (400 days of coobing f o r 6 i s t i l l a t i o n f e e d , as compared w i t h l e s s t h a n 36, days of cooling f o r s a l t sam$.es t e s t e d f o r m i s t f o r m a t i o n ) , it seems u n l i k e l y t h a t t h e m i s t concentrat i o n would have been h i g h enough t o e x p l a i n t h e h i g h r e l a t i v e v o l a t i l i -
t i e s f o r t h e s l i g h t l y v o l a t i l e f i s s i o n products.
I n a d d i t i o n t o t h e argument a g a i n s t t h e entrainment h y p o t h e s i s j u s t g i v e n , n o t a91 t h e d i s c r e p a n c i e s , f o r example, t h e v a r i a t i o n s i n t h e 90~r a c t i v i t y r a t i o of and t h e low v d u e for t h e e f f e c t i v e v o l a t i l i t y
8'~r/
of 137Cs,
44 e
e
2
would be explained by t h e entrainment h y p o t h e s i s .
Concentration P o l a r i z a t i o n Concentration p o l a r i z a t i o n would cause t h e e f f e c t i v e r e l a t i v e vola-
t i l i t i e s of t h e s l i g h t l y v o l a t i l e materials t o be h i g h e r t h a n t h e t r u e relative volatilities.
A s t h e m o r e - v o l a t i l e materials w e r e vaporized
from t h e l i q u i d s u r f a c e , t h e s l i g h t l y v o l a t i l e m a t e r i a l s would be l e f t behind a t a h i g h e r c o n c e n t r a t i o n t h a n i n t h e l i q u i d j u s t below t h e s u r face.
I n turn, t h e vapor-phase c o n c e n t r a t i o n of t h e s e s l i g h t l y v o l a t i l e
m a t e r i s l s would i n c r e a s e , s i n c e f u r t h e r v a p o r i z a t i o n would occur from a l i q u i d w i t h s u c c e s s i v e l y h i g h e r c o n c e n t r a t i o n s of s l i g h t l y v o l a t i l e materials.
Thus, s i n c e e f f e c t i v e r e l a t i v e v o l a t i l i t i e s were based on
+ . .... ..& ...,'
average c o n c e n t r a t i o n s i n t h e s t i l l pot, t h e vapor c o n c e n t r a t i o n would
44 be h i g h e r t h a n t h a t corresponding t o t h e average l i q u i d c o n c e n t r a t i o n , and t h e c a l c u l a t e d e f f e c t i v e r e l a t i v e v o l a t i l i t y would b e h i g h e r t h a n t h e t r u e r e l a t i v e v o l a t i l i t y , i f t h e concentrations a t t h e surface of t h e l i q u i d were h i g h e r t h a n average.
S i m i l a r l y , c o n c e n t r a t i o n polariza-
t i o n would cause t h e e f f e c t i v e r e l a t i v e v o l a t i l i t i e s of components w i t h r e l a t i v e v o l a t i l i t i e s h i g h e r t h a n l t o b e lower t h a n t h e i r t r u e r e l a t i v e
If mixing o r d i f f u s i o n d i d n o t reduce t h e c o n c e n t r a t i o n
volatilities.
g r a d i e n t i n t h e l i q u i d , t h e n t h e s e p a r a t i o n performed by t h e s t i l l would be a d v e r s e l y a f f e c t e d . A s noted i n r e f .
4, t h e
e x t e n t t o which c o n c e n t r a t i o n p o l a r i z a t i o n
a f f e c t s t h e e f f e c t i v e r e l a t i v e v o l a t i l i t y of a p a r t i c u l a r component depends on t h e dimens.ionless group D/vL, which q u a l i t a t i v e l y r e p r e s e n t s t h e r a t i o of t h e s a t e of d i f f u s i o n o f a p a r t i c u l a r component f r o l n t h e vapor-liquid
i n t e r f a c e i n t o t h e b u l k of t h e s t i l l - p o t l i q u i d t o t h e r a t e
a t which t h i s material i s t r a n s f e r r e d by convection t o t h e i n t e r f a c e by
l i q u i d moving toward t h e v a p o r i z a t i o n s u r f a c e . effective diffusivity
0%
In t h i s ratio, D is the
t h e component of i n t e r e s t , v i s t h e v e l o c i t y o f
l i q u i d moving toward t h e i n t e r r a c e , and E i s t h e d i s t a n c e between t h e i n t e r f a c e and t h e p o i n t where t h e f e e d i s i n t r o d u c e d . The occurrence of c o n c e n t r a t i o n p o l a r i z a t i o n i s suggested by t h e s h a r p r i s e , a t t h e beginning of t h e run, i n t h e e f f e c t i v e r e l a t i v e vola-
t i l i t i e s of 144Ce, 147h, "*Eu,
and, p o s s i b l y ,
and 9oSr.
This r i s e
would correspond t o t h e formation o f t h e c o n c e n t r a t i o n g r a d i e n t a t t h e beginning of t h e r u n .
The e f f e c t i v e d i f f u s i v i t i e s sf NdF
3
i n the still
pot
c a l c u l a t e d from r e s u l t s o f t h e n o n r a d i o a c t i v e experiments
from
1 . 4 x lo-'
to
16
x 10-
4
2 em / s e e .
4 ranged
They form the b a s i s f o r e s t i m a t i n g
c......:.;.
45 t h e magnitude of t h e c o n c e n t r a t i o n p o l u i z a t i o n e f f e c t i n t h e r a d i o a c t i v e operation.
During t h e semicontinuous o p e r a t i o n a t t h e MSRE, t h e l i q u i d
-4 cm/sec
v e l o c i t y r e s u l t i n g from v a p o r i z a t i o n averaged 2.2 x 18 depth of l i q u i d above t h e i n l e t w a s approximately
9.4 cm.
and t h e
I f one assumes
t h a t t h e e f f e c t i v e d i f f u s i v i t y o f t h e f i s s i o n products i n t h e s t i l l pot d u r i n g t h e E R E D i s t i l l a t i o n Experiment w a s i n t h e same range as thet
seen d u r i n g t h e n o n r a d i o a c t i v e t e s t s
t h e observed r e l a t i v e v o l a t i l i t i e s
of t h e s l i g h t l y v o l a t i l e materials would b e only 2 . 0 t o actual r e l a t i v e v o l a t i l i t i e s
, and
18 t i m e s
the
t h e observed r e l a t i v e v o l a t i l i t y of
would be 0.011 t o 8.021 t i m e s i t s t r u e v a l u e ( i n each c a s e , assuming
I3'Cs
%hat t h e t r u e r e l a t i v e v o l a t i l i t i e s were t h o s e given i n r e f s . 1 and 2 ) . Although c o n c e n t r a t i o n p o l a r i z a t i o n may have been p r e s e n t i n t h e work w i t h r a d i o a c t i v e s a l t , t h e e f f e c t w a s l e s s important t h a n t h a t needed t o account f o r t h e d i s c r e p a n c i e s between observed r e l a t i v e v o l a t i l i t i e s and what we consider t o be t h e t r u e v a l u e s .
Concentr-ation p o l a r i z a t i o n would
n o t e x p l a i n t h e v a r i a t i o n i n t h e r a t i o o f t h e a c t i v i t i e s of @Sr- and "Sr between sztmples.
4.4.3
Contamination
Samples
The p o s s i b i l i t y t h a t t h e condensate samples were contaminated during p r e p a r a t i o n f o r a n a l y s i s i s suggested by t h e extreme v a r i a t i o n i n t h e r a t i o o f 89Sr and "Sr
a c t i v i t i e s between samples.
Although r o u t i n e
p r e c a u t i o n s a g a i n s t s m p l e contamination were t a k e n i n t h e h o t c e l l s where t h e c a p s u l e s were c u t open, no s p e c i a l p r e c a u t i o n s were t a k e n . (The sme manipulators t h a t are used t o handle MSRE s a l t samples were employed f o r opening t h e s e condensate samples.
1
If it i s assuaged t h a t
t h e source of t h e contamination w a s a sample from t h e MSRE taken just
46 b e f o r e t h e condensate a n a l y s e s were s e n t t o t h e h o t c e l l s , t h e n t h e m o u n t of r a d i o a c t i v e m a t e r i a l necessary t o r e s u l t i n t h e observed v a l u e s
of t h e r a t i o of 89Sr and "Sr per gram of sample.
a c t i v i t i e s w a s i n t h e range
to
g
Prevention of such a low l e v e l of contamination i s
extremely d i f f i c u l t . Other o b s e r v a t i o n s t h a t can be explained by assuming t h a t t h e samples were contaminated a r e t h e high r e l a t i v e v o l a t i l i t i e s o f t h e s l i g h t l y vola t i l e f i s s i o n p r o d u c t s and t h e high c o r r e l a t i o n between t h e v a r i a t i o n of c a l c u l a t e d r e l a t i v e v o l a t i l i t i e s of d i f f e r e n t f i s s i o n products.
other hand, t h e low r e l a t i v e v o l a t i l i t y for '3'Cs t h i s hypothesis
4.4.4
On t h e
i s not explained by
e
I n a c c u r a t e Analyses The a n a l y s e s f o r 95Zr, 137Cs,
144Ce,
"Sr,
and @Sr
were made by
proved, r e l i a b l e methods and a r e considered t o be a c c u r a t e w i t h i n The a n a l y s e s f o r 14'h and "Y
2 5%.
a r e thought t o be l e s s r e l i a b l e b u t ,
nevertheless, accurate t o within
-+ 10%. analysis for ' 5 5 ,
s
was difficult;
t h e r e f o r e , t h e r e s u l t s a r e only approximate and t h e i r accuracy i s open t o question.
10
The a n a l y s e s f o r
1 4 4Ce, which were made by gamma scanning and by
radiochemical s e p a r a t i o n techniques u s i n g s e p a r a t e p o r t i o n s of t h e cond e n s a t e samples, appeared t o be a c e m a t e .
Good agreement w a s obtained
between t h e two sets of a n a l y s e s .
,.. ...,...:"
47 5.
CONCLUSIONS
The f o l l o w i n g conclusions were dram from t h e r e s u l t s o b t a i n e d i n t h e experiment d e s c r i b e d above.
1. The s e p a r a t i o n of f u e l c a r r i e r s a l t from the l a n t h a n i d e f i s s i o n p r o d u c t s w a s demonstrated by p r o c e s s i n g 1 2 l i t e r s of f u e l s a l t from an o p e r a t i n g r e a c t o r .
Although t h e
volume of s a l t t h a t was processed w a s less t h a n a n t i c i p a t e d ,
a l l t h e important features of t h e o p e r a t i o n were adequately tested.
The o p e r a t i o n of t h e equipment f o r t h i s run w a s
smooth and t r o u b l e - f r e e . 2.
The e f f e c t i v e r e l a t i v e v o l a t i l i t i e s f o r BeP2 and ZrF4 (based on b o t h n a t u r a l zirconim. and f i s s i o n product 952,) agreed w i t h previous l a b o r s t o r y measurements.
3.
The upper l i m i t of t h e r e l a t i v e v o l a t i l i t y of 13'C!s,
e f f e c t i v e i n t h i s run, w a s found t o be o n l y about 28% of t h e v a l u e measured i n t h e l a b o r a t o r y
We cannot adequately
e x p l a i n t h i s discrepancy i n t e r n s sf t h e occurrence o f l i q u i d entrainment, concentration p o l a r i z a t i o n i n t h e still
4.
o r condensate s a p l e c o n t a n i n a t i o n .
The e f f e c t i v e r e l a t i v e v o l a t i l i t i e s for t h e l a n t h a n i d e f i s s i o n products 144Ce and n47h w e r e unexpectedly h i g h . The e f f e c t i v e r e l a t i v e v o l a t i l i t y of l 4 4 ~ ewas about
t i m e s t h a t i n d i c a t e d by previous measurements. p r e v i o u s measurements f o r
'47h
56
No
were a v a i l a b l e ; however,
t h e r e l a t i v e v o l a t i l i t y i s thought t o be c l o s e t o t h a t o f
CeP3.
It i s b e l i e v e d t h a t the discrepancy between
observed v a l u e s and previous measurements i s , in p a r t , due t o sample contamination.
5.
Even i f t h e r e l a t i v e v o l a t i l i t i e s of t h e l a n t h a n i d e s are as
high 8s seen here (W.019,adequate recovery of 7LiF
from w a s t e s a l t streams by d i s t i l l a t i o n i s still p o s s i b l e .
48 Lf t h e r e l a t i v e v o l a t i l i t i e s o f t h e r a r e - e a r t h f l ~ o r i d e s were as h i g h as 0.01, o n l y 3% of t h e rare e a r t h s would be vo%atilized during v a p o r i z a t i o n of 95% of t h e PrEiP i n a batch d i s t i l l a t i o n .
6.
ACmowLmGmms
The a u t h o r s g r a t e f u l l y acknowledge t h e h e l p of t h e following people
i n t h e i n s t a l l a t i o n , o p e r a t i o n , and a n a l y s i s of t h e %RE Experiment:
P. M. Haubenreich, W. H. Guymon, E'.
Distillation
H. Harley, A. I .
Krakoviak, and M. Richardson, sf t h e Reactor D i v i s i o n ; W. W. Tucker of t h e I n s t r u m e n t a t i o n and Controls D i v i s i o n , R. B. LindaUer of t h e Chemical Technology D i v i s i o n ; J.
H. Moneyhun of t h e Analytical Chemistry D i v i s i o n ;
8. S. Jackson of t h e P l a n t and Equipment D i v i s i o n ; and 8 . 0.
Payne,
V. E. Fowler, J. Beams, F. L. Rogers, E. I?. J o h n s , and J.
Rose,
C.
t e c h n i c i a n s i n t h e Unit Operations S e c t i o n of"t h e Chemical Technology Division.
w
49 7.
REFERENCES
1. 3 . R . Hightower, Jr., and %. E. McMeese, Measurement of t h e R e l a t i v e V o l a t i l i t i e s of F l u o r i d e s of Ce, La, P r , Nd, Sm, Eu, B a , S r , Y, and
Zr i n Mixtures sf LiF 2.
OWNL-TI-2058
(January
1968).
F. J . Smith, L. M. F e r r i s , and C . T. Thompson, Liquid-Vapor E q u i l i b r i a i n LiP-BeF,
and LiF-BeF,-ThF4
Systems, OWML-4415 (June
1969).
L
L
3.
a-BeF,,
W. E. C a r t e r , R. B. Lindauer, and L. E. McNeese, Design of an Engineering-Scale Vacuum D i s t i l l a t i o n Experiment f o r Molten S a l t Reactor F u e l , OR63L-TM-2213
4. J.
3 . Hightower,
(November
19689 -
Jr., and E. E. McNeese, Low-Pressure D i s t i l l a t i o n
o f Kolten Fluoride Mixtures :
Nonradioactive Tests f o r t h e MSRE
D i s t i l l a t i o n Experiment, OREL-4434 (January $1. 'd.
Rosenthal,
ORâ&#x201A;Ź&-4919, F.
6. M. W.
1971). 9
76.
Wosenthal,
OREL-4396, p. 24. 7.
E. E. Compere., ORNL, p e r s o n a l communication, J u l y 1,
8.
M. W. Rosenthal ,
1969. Y
ORm-4254, p . LOO. 9.
M. W. Wosenthal, MSR P r o g r t ~Semiann. ~~ Progr. Rept. Feb. 28, 1969,
0~~~-439 p.6 1-45. , J. H. Moneyhm, QRNL, p e r s o n a l conmunication, Feb. 9, 1970.
8.
..
.. ... .......
~
..X,.,&.,,.P
APPENDIX:
ANALYSES O F SAmEES PROM TEE YSRE DISTILLATIOM EXPEPIPbEITT
53
Table A - l .
Li
Be
Zr
(wt %)
(wt. % )
( w t $)
11.14 8.48 10.39 9.76
15.66
(ais
rnin-lg-l-1
Analyses of Samples from t h e MSRE D i s t i l l a t i o n Experiment
( d i s min-lg-')
(dis min-lg'l)
(ais
mira'lg-1)
( d i s min-lg-1)
(ais min-lg-1)
( d i s min-lg-1)
(dit, mTn'-lg-')
S a l t Volumes Associated w i t h Condensate Samples Total L i t e r s L i t e r s Condensate Fed Collect ea
Fuel storage tank-1 (Date analyzed)
Fuel storage tank-2 (Date analyzed) Condensate samples -1 -2
-3
-4 -5 -6
-7 -8
-9 -10 -11
(Date analyzed 1
8
3.88 4.67 6.86 7.24 8.15
10.00
l.o.09
1.53 109 1.39 x lo9 1.14 x l o 9 1.17 109
10.48
1.24 x 10'
12.05
10.04
9.93 i o . 49 9.24 10.53 8.48 9.83 7.66 8.71 13.02 5.11 8.26 13.28 5.22 8.11 (5/21/69) (5/23/69) (5/23/69) 7.05 7.82 8.77 9.80
k p l i e a t e samples d i f f e r e d by a f a c t o r o f 4 or more.
1.16 109 1.17 1 ~ 9 9.78 x 1 08 9.44 x 1 08
6.83 x lo6 1 . 2 1 x 108 2.39 x 108 1.97 x 108 8.09 x lo7 2.89 x i o8 8 1.99 x 1 0 3.01 x 108 4.63 x 108 4.75 x 1 08
9.25 x 108 (5/21/69)
4.91 x 108 (?/21/69)
1121
109
<2.6 x i o 6 1.53 x 10'1 2.78 x 107
107 8.85 x 1 06
2.23
3.20 x
lo7
2.16 x 107 3.08 107 5.98 107 6.27 107 6.90 x 107 (7/2/69 1
6.54 1.18 1.44 1.32 6.14 1.81 1.15 1.60 2.29 6.01
105 x 106 x
106
x 106 x
lo5
x 1 06 x i o6 x x
lo6 i o6
x 106
4.10 x 106 ( 9/30/ 69)
< 2 . 1 x 1 06
<5.2 x 1 06 8.54 x 1 06 5.76 x 1 06& e . 5 x 1 06. 8.93 x 1 06 8.57 x 106 8.75 x 106 1.56 x 1Q7 2.37 x 1 07 3.04 107 (7/8/ 69 1
9.46 109 6.49 x lo8 3.93 x 109 3.53 109 3.14 109 2.61 x 109 1.66 x 109 5.91 x lo8 4.06 x lo8 2.63 x lo8 2.96 x lo8 ( 5/ 21/ 69 1
7.9
0.42
10.0
1.93
11.2
2.96 3.81 4.35 4.95 5.80 6.34 6.89
12.6 13.4
13.6 13.8 13.8 13.8 13.8 13.8
1
7.49 7.85
55
ORNL-4574 UC-80 -Reactor Technology
INTERNAL DISTRIBUTION 1-3. Central Research Library 4-5. FlSRP Director's Qffice 6. OWE - Y-12 Technical Library Document Reference Section 7-41. Laboratory Records Department 42. Laboratory Records, ORNL R.C. 43. R. K. A d a m 4 4 . e. M. Adamson 45. s. E. Anderson 46. C . F. Baes 4 7 . 6 . E. Bamberger 48. C. J. Barton 49. H. F. Bauman 50. S. E. Beall 51. M. J. Bell 52. E. S. Bettis 53. R. E. Blaneo 54. P. F. Blankenship 55. J. 8 . Blomeke 56. R. Blumberg 57. E. G . Bshlmann 58. G . E. Boyd
59. J. 68. M. 61. R. 62. s. 63. W. 64. M. 65. E. 66. W. 67. B. 68. J. 6 9 . P. 70. J. 71. S. 72. W. 7 3 . J. 7 4 . D. 75. L.
Braunstein A . Bredig
B. Briggs Cantor L. Carter D. Cochran, Jr. k. Compere H. Cook Cox L. Crowley
E. C u l l e r PI. DeVan J. D i t t o B. Eatherly
a. Engle E. Ferguson M. Ferris
76. A. P. Fraas 77. W. R. Grimes 78. A. G . Grindell
79. R. H. Gupon 80. B. A. Hannaford 81. P. B. Harley 82. P . N. Haubenreich 83. R. F. Hibbs
R. Hightower, Jr. W e Hoffman W. Horton H. Jordan 89. P o R . Kasten
84-85. J . 86. H. 87. R. 88. W.
98. C. Id. Kee
91. M. J. Kelly 92. S. %.Mirs1is 9 3 . J . W. Koger 9 4 . K. B. Korsmeyer
95. A . I. Krakoviak 96. T. S. Kress 97. J. A . Lane 98. R. B. Eindauer 99. A. P . Litman 100. M. I. Lundin 101. H. G . MacPherson 102. J. C. Mailen 103. H. E. McCoy 1 0 4 . L. E. McNeese 105. A . S. Meyer 166. R. L. Moore 107. D . M. F f Q U 1 t O n 188. 9. P . NickoPs 109. E. L. Nicholson
110. A. N. Perry 111. J . E. Redford 1 1 2 . M. Richardson 113. G . D. Robbins 114. K. A . Romberger J. Roth
115. 116. 117. 118. 119. 120.
121. 122. 12%. 124. 125.
W. P. Schaffer Bunlap Scott J. H. Shaffer M. J . Skinner A. N. Smith E'. J. Smith D . A. Sundberg R. E. Thsrna I). B. Trauger Chia-Pao Tung W. E. Unger G . M. Watson
126. 127. 128. A. M. Weinberg 129. J. R. Weir 130. M. E. Whatley 131. J . C. White
56
3.32. Gale Young 133. E. L . Youngblood 134. P . H. Emmett (consultant) 135. J. J. Katz (consultant)
136. 6. E. Ice (consu%tant) 1 3 7 . E. A . Mason (consultant) 138. R. â&#x201A;Ź3. Richards (consultant)
EXTERNAL DISTRIBUTION
139. A. Giambusso, U.S. Atomic Energy Commission, Washington, D . C . 140. Kermit Laughon, AEC Site Representative, ORNL 141-142, T. W. McIntosh, U.S. Atomic Energy Commission, Washington, B.C. 143. M. Shaw, U.S. Atomic Energy Commission, WashPngt~n,D.C. 144. 3 . A . Swartout, Union Carbide Corporation, New Y w ~ , N . Y . 10019 145. Laboratory and University Division, AEC, OR0 146. Patent Office, AEC, OR0 147-149. Director, Division of Reactor Licensing, U.S. Atomic Energy Commission, Washington, D.C. 150-151. Director, Division of Reactor Standards, U.S. Atomic Energy Commission, Washington, D e C . 152-375. Given distribution as shown in TIB-4500 under Reactor Technology category (25 copies - NITS)
.... .: w,.;.;.>y Y