ornl tm 0528
DESCRIPTION
http://www.energyfromthorium.com/pdf/ORNL-TM-0528.pdfTRANSCRIPT
- , 4
O A K RIDGE NATIONAL LABORATORY operated by
UNION CARBIDE CORPORATION for the
U.S. ATOMIC E N E R G Y COMMISSION
ORNL- TM- 528 -~. -..
DESIGN AND OPERATION OF FORCED-CIRCULATION
CORROSION TESTING LOOPS WITH MOLTEN SALT
J. L, Crowley W. 8. McDonald D. L. Clark
NOTICE This document contains information of a preliminary nature and was prepared primarily for internal use at the Ook Ridge National Laboratory. I t i s subiect to revision or correction ond therefore does not represent a final report. The information i s not to be abstracted, reprinted or otherwise given public dis- semination without the approval of the ORNL patent bronch, Legal and Infor- mation Control Department.
I
LEGAL NOTICE
Th is report was prepared as on account of Government sponsored work. Neither the United States,
nor the Commission, nor any person acting on behalf of the Commission:
A. Makes any warranty or representotion, expressed or implied, w i th rmspoct to the accuracy,
completeness, or usefulness of the information contained i n th is report, or that the use of
any information. apparatus, method, or process disclosed i n th i s report moy not infr inge
pr ivate ly owned r ights; or
6. Assumes ony l i ob i l i t i es w i th respect t o the use of, or for domoger resul t ing from the use of
any information, apparatus, method, or process disclosed i n th i s report.
As used i n the obove, "person act ing on beholf o f the Commission" includes any employee or
contractor of the Commission, or employee of such controctor. to the extent that such employee
or controctor of the Commission, w employee of such controctor prepares, dinseminotes. or
provides access to, ony informotion pursuont to h i s employment or controct w i th the Commission,
or h i s employment w i th such controctor.
' ...
C o n t r a c t N o . W - 7405 -eng-26
R e a c t o r Division
DESIGN AND OPERATION OF FORCED-CIRCULATION CORROSION TESTING LOOPS WITH MOLTEN SALT
J. L. C r o w l e y W . B . M c D o n a l d D . L . C l a r k
D a t e Issued
MAY - 1 1963
OAK RIDGE NATIONAL LABORATORY Oak R i d g e , Tennessee
operated by UNION CARBIDE CORPORATION
for the U . S . ATOMIC ENEBGY COMMISSION
ORNL-TM-528
h
t iii
CONTENTS
Ab s t r a c t
In t roduc t ion
Descr ipt ion of Test Loop and Auxil iary Equipment
Alarm and Automatic-Action Controls
Operation and Maintenance of a T e s t Loop
Summary
Acknowledgments
Page
1
1
2
1 5
17
21
21
7
.
DESIGN AND OPERATION OF FORCED-CIRCULATION
CORROSION TESTING LOOPS WITH MOLTEN SALT
.
J. L. Crowley W . B. McDonald D. L . Clark
Ab s t r ac t
StandardLzed t e s t f a c i l i t i e s were developed and oper- ated f o r i n v e s t i g a t i n g t h e compat ib i l i ty of s t r u c t u r a l materials and flowing molten f l u o r i d e salts . The s tandard loop accommodates var ious combinations of materials, f l u i d s , flow r a t e s , and t m p e r a t u r e d i f fe ren t ia l s and permits f a b r i c a t i o n of comjtonents i n s u f f i c i e n t quan t i ty f o r c o s t reduct ion . The t e s t loop c o n s i s t s of a pump, two heated sec t ions , a cooled sec t ion , a d r a i n tank, and a frozen- plug-type valve. Automatic con t ro l s and equipment were developed t o prevent s o l i d i f i c a t i o n of t h e sal t mixtures (m.p., 800 t o 1100°F) i n the event of a loss of power. Most t e s t loops are f a b r i c a t e d of 0.5-in.-o.d. , 0.045-in.- w a l l tubing, and they operate with a temperature d i f f e r - e n t i a l of up t o ZOOOF, a maximum w a l l temperature i n t h e range 1200 t o 1500C’F, and a sa l t flow rate of up t o 3 gpm. Twenty-five t e s t loops have been operated f o r an accumu- l a t e d operat ing time-- of Z90,OOO h r . been operated continuously f o r more
Ind iv idua l 1 oops have than one yea r .
In t roduct ion
Mixtures of molten f l u o r i d e salts have been inves t iga t ed ex tens ive ly
f o r a p p l i c a t i o n i n r e a c t o r systems as f l u i d f u e l s or as h e a t transfer
media.
conta iner a l l o y i s detemnined, i n p a r t , by t es t s with thermal-convection
loops,’ and t h e most promising combinations of sa l t mixtures and
s t r u c t u r a l material are i;hen s tud ied i n fo rced -c i r cu la t ion cor ros ion
t e s t loops . These loops simulate a l l e s s e n t i a l r e a c t o r opera t ing con-
d i t i o n s except r a d i a t i o n m 2
i z e d t o permit ready repilacement and t o minimize f a b r i c a t i o n c o s t s and
i n s t a l l a t i o n t ime.
The compat ib i l i ty of a p a r t i c u l a r salt mixture with a proposed
The t e s t s tands and loops have been s tandard-
Many mixtures of mo:lten salts have been t e s t e d . The bas i c con- s t i t u e n t s of t h e s e have -2een t h e f l u o r i d e s of sodium, l i thium, beryll ium,
t
2
z i r c o n i m , thori,Jm, ar2d uracium i n va r ious p ropor t i cns t h a t g ive melt ing
temperatures gene ra l ly f a l l i n g i n t3e 800 t o llOO0F range.
and d e n s i t y vary with each mixture.
axount of b e y j r l l i ~ x Frese:?_t wid t k e der:sit,y f z c x e s e s : h i i t k ? t h e anmmt of h?ez,vy elcment,s prest t.
ct:r:t.ipoLse en? E sp~.cZZj_c gya:iity of 2 . 4 et I I C O F. c orz~.:riFng k e r y L l i z - e q d re s t z i n g e c t saf z t ; ~ p-scaut,ions t.0 prevent ex-
posure of p e r s o x e l t o t -2 -L~ t o x i c nateriai .
V i scos i ty
The v i s c o s i t y i n c r e a s e s with t h e
!- t y p i c a l sa l t rnlxt?ire k r s h Tiiscosity of 10 3
T'-p sal t mixtures . I
rn p r e d i c t ecc:?.retelg co r ros ion r a t e s f o r power r eac to r s , t h e t e s t s
r m s t necessa r i ly be of long-term ciuratioi?. Tl.e t z s t sts~zci c o n t r o l
s p t m w z s t?ie:mefcr? ciesigced not only t o m & i E t & i c .the necessary t e s t
co_rditions for i o ~ g per iods of opera+,ior bat aisc t o provide a x t o m t i c
p r c t e c t i o x agaiwt scl i2ff isatLon cf t h e sai t i n t3e system. S i m e
melting of t h e sait iinpcses sewx-e stresses or? t h e c o c t a i n e r w a l l , re-
melt ing a f t e r s o l i d i f l e a t i m migkt cause premature f a i l u r e of t h e loop.
The tes t l cop i s I l l s s t re t ,ed i n Fig. 1. m, J.LY loop c o e s i s t s of a
punp,, two heatzd sectioris, 8 cooled sect.ion, a ?.rc,ic t.a;-k, and a f rozen-
plug-type -;sive. . A l l w e t k d p a r t s of t h e ioop are fa-9r icated of t h e
a l l o y be icg s tud ied . Loop tubirg s i z e i s s e l e c t e d t o provide t h e proper
c o n d i t i o x i f o r e l e @ t r F c a l = r e s l s t a ~ c e h e a t i n g and t o g ive a p res su re drop
a t design flo-+. that, i s c m s i s t e r i t w i t l ; t h e pwnp c a g a b i i i t y . A flow
d i a s r m 52' t:?? IYZ~- -LSE-S~ . - + c i r cu2z and t h e a a x i l i e r y co.ntrols f o r t h e
- fi1er-t COITF;:~ g:es 225 c:tflitLt-s is sh.owr; ir, Fig" 2 .
A stz,n??ard lcoy, sv.ypar-kd ky i t s mobile bily i s p i c t w e d i n
Fig. 3 . T k i s s-tec2zrd I m p was developed from expe r i e ixe gaiced i r ?
zaxy tes t s t o accsmiodate t h e v a r i m s combinatiozs of materials, f l u i d s ,
~ l o w r a t e s , a temperttu:?e g r e d i e s t s de s i res- Such s t anda rd i z a t i on
has permit ted f 'ehricr, t ion of components i n quan t i ty f o r both c o s t re-
dimction ar_? eese zjf a.ese%bly-o
and star& .~,LIows +;;I?J f 'a-arlcat.ior, of stacd5y t e a t loop zssemblies f o r
quick replasemezt v i t h 8 ?xLrlim.m of dowr? the.
o.d. , O.C45-in.-wall -Lg.-oiii?g has been fcund t o 3e su5 tab le .
--
The i n t e r c h a n g e a 3 i l i t y of t h e t e s t loops
F o r x o s t tests, O.5-in. -
. I
1
I
‘ l c ,
UNCLASSIFIED ORNL-LR-DWG 64740
110kva -:r POWER SUPPLY
/
1600-amp BREAKER
-~“B” AA ,
(0 kva POWER SUPPLY
Fig. 1. Molten-Salt Corrosion Testing Loop and Power Supplies.
Unclassified Photo 34533
MAGNETIC CLUTCH 8 5HP
, ' > SHAFT AN0 SEAL OIL -
FLOW ALAR
COOLING WATER
SUPPLY
HELIUM SUPPLY
L
,,:;,"ZE ;LVE\
AIR
p F
I I I 1
DRAIN TANK
AIR VENT
EQUIPMENT IDENTIFICATION
FG-FLOW INDICATING GLASS, NON- CALIBRATED F I - FLOW INDICATOR
HCV-HAND- ACTUATED CONTROL VALVE HV-HAND-ACTUATED BLOCK VALVE PI- PRESSURE INDICATOR PV-PRESSURE CONTROL VALVE
XV-CHECK VALVE TI- TEMPERATURE INDICATOR
SI-SPEED INDICATOR SC-SPEED CONTROL LL-LEVEL LIGHT
J& PRESSURE CONTROL VALVE -W- VALVE, NORMALLY CLOSED Q VALVE, NORMALLY OPEN
+CHECK VALVE (XV)
Fig . 2 . Flow Diagram of Molten S a l t Loop and Ut i l i t i e s .
!
5
i
Unclassified
Fig. 3. Photograph of Molten-Salt Corrosion Testing Loop on Mobile Dolly.
6
The flow rate, Reynolds number, p re s su re drop, and power required
f o r t h e h e a t e r s e c t i o n s a r e c a l c u l a t e d using t h e phys ica l p r o p e r t i e s
of t h e p a r t i c u l a r sa l t mixture an2 t h e perfolrmance c h a r a c t e r i s t i c s of
t h e pump.
A l o o p p res su re drop ( f ee t of head) vs flow (gpm) curve i s determined
by m i n g t h e phys ica l p r o p e r t i e s of t h e molten salt t o be t e s t e d and t h e
geometry of t h e l o o p . Ey superimposing t h i s c m v e on t h e pump operat ing
c h a r a c t e r i s t i c curve, as shown i n F ig . 4, t h e d e s i r e d flow r a t e i s
determined wi th in t h e Lirr i ta t ions of aliowzble puxp speed.
The e l e c t r i c a l r e s i s t i v i t y of +,he rc;ol-Len sal t i s enough h ighe r t h a n
t h a t of t h e metal con ta ine r w a l l s t h a t it can be neglected i n determining
t h e power requiremects of t h e hea-cer s e c t i o n s . The t ransformer vo l t age
r equ i r ed f o r t h e p a r t i c u l a r salt mixture shown i n Pig. 4 w a s c a l c u l a t e d
according t o t h e e l e c t r i c a l r e s i s t a n c e of t h e h e a t e r s e c t i o n tubing, t h e
flow rate, and t h e d e s i r e d b d k f l u i d temperature d i f f e r e n c e . The power
r equ i r ed of t h e t ransformer w a s 58.8 Kw a t 1250 amp and 47.2 v o l t s . The
two h e a t e r s ec t ions , 96 i n . and lo9 i n . i n length, are connected t o t h e
power supply t r a n s f o r n e r i n p a r a l l e l and c a r r y 665 and 585 amp, respec-
t i v e l y .
imparts a higher h e a t f l c x where t h e bu lk f l u i d temperature i s t h e
lowest .
ternperatires a t t h e o u t l e t of bo th h e a t e r s . A w a l l temperature and bulk
f l u i d t e n p e r a t z r e p r o t i l e of E. t y p i c a l loop while i n ope ra t ion a t t e s t c o a d i t i o l s i s sho~n Zr Fig . 5. s t r a i g h t s e c t i o n s of t h e tu5ixgg, during ~ o r m a l operation, t o e l imina te
ho t s p o t s caused 5y poo? flow d i s t r i b u t i o n i n t h e tub ing bends.
h e a t e r s e c t i o n s are used t o reduce t h e o v e r - a l l l e n g t h of t h e loop t h a t
wo-dd be necessary t o ob ta in t t e d e s i r e d f l u i d temperature with one con-
t i n c o u s h e a t e r s e c t i o n . The flow of c u r r e n t i s r e s t r i c t e d t o t h e h e a t e r
sectiofis during operat ion a t t e s t cond i t ions by t h e nethod of attachment
t o t h e t ransformer. O x t e rmina l of t h e t ransformer i s connected t o t h e
o n t l e t of t h e second h e a t e r s e c t l o n and t o t h e l d e t of t h e f i rs t h e a t e r
s e c t i o n . The o u t l e t of t h e f i r s t h e a t e r and t h e i n l e t of t h e second
h e a t e r are siar1lar;y connectec! t o t h e o the r t ransformer t e rmina l .
loop i s grouEde3 a t t k pimp, whlie t h e renainder of t h e loop i s
The s h o r t e r f irst s e c t i o n (96 i n . ) has l e s s r e s i s t a n c e and
This arrangement r e s u l t s i c approximately equal maximum w a l l
The 12R hea t ing i s app l i ed only t o
Two
The
c -
it
P
.
U N C L A SS IF1 ED ORNL- LR-DWG 65065
110 - I I 1 I I
100
90
80
70 A
c + Y
60 0
W I a
a 50 5 a
40
30
20
10
0 0 1 2 3 4 5 6 7 8
FLOW (gpm)
Fig. 4 . Performance C h a r a c t e r i s t i c s of C e n t r i f u g a l Pump, Model LZB.
1300
1250
c 1200 LL v
i150 l-
[L
a
a w (100
I- 4050 5
to00
950
UNCLASSIFIED ORNL-LR-DWG 65066
0 400 200 300 400 5 00 600
LENGTH (in.)
Fig. 5 . Temperature Profile of Corrosion Loop a t T e s t Conditions.
9
.
e l e c t r i c a l l y in su la t ed .
A t tes t condi t ions, from 350 t o TOO amp of 60-cycle a l t e r n a t i n g
cu r ren t flows i n each h e a t e r s ec t ion a t a p o t e n t i a l of 25 t o 50 v.
E l e c t r i c a l current ' i s suppl ied t o t h e h e a t e r s ec t ions through a n icke l
lxg welded t o a thick-walled adapter s e c t i o n of t h e loop.
'I3e power f o r t h e h e a t e r sect ior , i s scppi ied by a 110-kva t r a n s -
f omer kaving a low-voltsge high-current secondary winding, with a
sa turable-core r e a c t o r on t h e primary s ide .
pyrometer r egu la t e s t h e 3-c vol tage t o t h e sa tu rab le r e a c t o r and de te r -
n ines t h e vol tage appl ied t o t h e h e a t e r s ec t ion of t h e loop by t h e main
power t ransformer.
h e a t e r s ec t ion i s l i m i t e 3 by a maximum-adjustment rheos t a t t h a t l i m i t s
t h e d i r e c t cu r ren t ava i lcable t o t h e sa tu rab le r eac to r .
A propor t iona l -cont ro l
The mount of power which may be appl ied t o t h e
A loop high-temperature alarm i s designed t o c u t of f t h e d i r e c t
cu r ren t t o t h e sa tu rab le r e a c t o r and t o reduce t h e power t o a minimum
leakage value. When t h e loop temperature again drops below t h e alarm
set poin t , t h e automatic a c t i o n r e l a y i s reset and t h e power i s re-
appl ied a t t h e rate previously se t . The high-temperature alarm thus
serves as an "on-off" c o Q t r o l of t h e power i f an emergency condi t ion
occurs.
The t ransformer i s connected t o t h e loop hea te r l u g s by a 5OO,OOO-
c i r c u l a r - m i l l s cab le through a 1600-amp breaker .
t h e connections of t h e h e a t e r s ec t ion are such t h a t t h e cu r ren t f low i s
confined t o t h e two h e a t e r s ec t ions (4 connections t o t h e loop) .
ever, when it i s necessa:ry t o prehea t o r provide emergency hea t ing t o
the e n t i r e loop, t h e 1600-amp breaker shown i n Fig. 1 i s t r ipped , leav ing
only two connections t o t h e loop.
cep t ion of t h e cooler c o i l , i s heated by t h e formation of two p a r a l l e l
pa ths of nea r ly equal r e s i s t a n c e .
During normal opera t ion
How-
Thus t h e e n t i r e loop, with t h e ex-
A downflow cen t r i fuga l sump pump designed a t ORNL i s used.
of t hese p u ~ p s have been f a b r i c a t e d of fou r d i f f e r e n t materials. An
accumulated t o t a l of approximately 450,000 h r of operat ion i n cor ros ion
t e s t i n g loops and o the r high-temperature pumping app l i ca t ions has demon-
strated t h e i r r e l i a b i l i t ~ r . ~ ~ As shown i n F ig . 6, t h e pump has an over-
h x r ~ v e r t i c a l s h a f t with an o i l - l u b r i c a t e d f ace seal above t h e l i q u i d
Over 40
10
UNCLASSIFIED ORNL-LR-DWG 3095A
LIQUID
I M PELL
-
2 in.
n.
11
I
t
W
.
I
U
?.
l e v e l i n an i n e r t - g a s atmosphere. Cooling of t h e s h a f t and seal i s pro-
vided by a flow of o i l down through t h e hollow s h a f t and out p a s t t h e
seal. The i n l e t t o t h e pump i s loca ted on t h e s ide, and t h e o u t l e t i s
a t t h e bottom. %e pe r fo rmaxe c h a r a c t e r i s t i c s of t h e pump f o r var ious
pump speeds are given i n Fig. 4. i s used f o r most long-teim opera t ion .
A pump speed of approximately 3000 rpm
T!e cent , r i fuga l puq) i s dr iven through dou5le V-belts by a va r i ab le -
speid magnetic c lu t ch and a 5 hp motor. The speed i s regula ted by an
e l e c t r o n i c con t ro l supplying d-c t o t h e magnetic-clutch u n i t . I n order
t o decrease t h e p o s s i b i l i t y of a flow stoppage as a r e s u l t of an
e l e c t r o n i c u n i t f a i l u r e , an a u x i l i a r y d-c source i s suppl ied f o r t h e
magretic c lutch, which is p r e s e t a t t h e des i r ed speed. This c lu t ch
supply c i r c u i t i s shown schematical ly i n Fig. 7. Relay SR-3 automatical ly
changes over t o t h e a u x i 1 i a . r ~ supply i f any pe r tu rba t ion of t h e normal
con t ro l occurs . The operat ion of t h e pump i s thelz maintained by t h e
aux i l i a ry -c lu t ch supply, while e l e c t r o n i c tubes are changed o r o the r
r e p a i r s are being made t o t h e normal supply. I n t h e event of t h e f a i l u r e
of both c lu t ch suppl ies o r a motor f a i l u r e , s t e p s are taken au tomat ica l ly
t o provide h e a t t o t h e e n t i r e loop, as w i l l be discussed f u r t h e r i n t h e
following sec t ion on alarm and automatic-act ion con t ro l s .
Since t h e pump conta ins t h e only gas- l iqu id i n t e r f a c e of t h e system,
a sampling device6 and l e v e l i n d i c a t o r s are mounted on t h e pump bowl
f lange . The maximum and minimum l i q u i d l e v e l s are ind ica t ed by a spark-
plug-type probe which l i g h t s an i n d i c a t o r as t h e molten salt comes i n
contac t with it. A c ross - sec t iona l view of t h e sampling device i s shown i n Fig. 8.
It c o n s i s t s of a dynamic-seal and bal l -plug-valve arrangement through
which a d i p tEbe can be i n s e r t e d i n t o t h e molten sal t and a sample with-
drawn without contaminating t h e i n e r t - g a s covering t h e l i q u i d i n t h e pump
bowl. The samples, which are removed p e r i o d i c a l l y f o r chemical ana lys i s ,
i n d i c a t e t h e type and rate of i nc rease of var ious cor ros ion products i n
t h e molten sal t .
I n p repa ra t ion f o r tak ing a sample, a seal i s e s t ab l i shed around t h e
per iphery of t h e sample tube, and t h e i n e r t gas i s introduced t o purge
t h e v o l m e between t h i s seal and t h e b a l l plug valve below. The b a l l
12
PYROMETEQ
SRI-4
OPENS ON CLUTCH
LOW SPEED
OPENS ON
TEMPERATURE
OPENS ON CLUTCH 1
SRI-4
LOW SPEED
OPENS ON
TEMPERATURE
BYPASS OPEN ON OPERATE
CLOSED ON LOW TEMPERATURE
CLOSED ON TEST
(TIME DELAY TRANSFORMER TAP
"OFF"
AMPLIFIER
AUXILIARY CONTROLS
MAIN RESISTANCE HEATER CIRCUIT
5 2 T
OPENS ON LOOP HIGH TEMPERATURE
OPEN ON PREHEAT CLOSED ON OPERATE
I MAIN RESISTANCE HEATERS CONTROL
r-
CLOSES ON
LOW CLOSES TEMPERATURE ON LOOP L'g?' SIMPLYTROL PYROMETER
HETEQ RELAV
TACHOMETER SPEED AND LOW TEMPERATURE CONTROL
IPENS ON LOSS OF CLUTCH
r A-C PUMP MOTOR CIRCUIT POTENTIAL
t 63 ORMAL SUPPLY t MAIN RESISTANCE
HEATER POTENTIAL
TACHOMETER CIRCUIT =@=I L - S U P P L Y FOR BLOWER MOTOR 4
I 0 0-100 Y DC I I
MAIN RESISTANCE pp HEATER Y T E N T I A L -7
CLOSED AT STARTUP OF OPERATION TO
ALLOW PICKUP OF RB. OPEN AFTER STARTUP-
DAMPER CONTROL
c L u r c n AUXILIARY 0 - c SUPPLY
OPEN ON LOSS
OPEN ON RESET AN0 PREHEAT
CLOSEO ON OPERATE
-it--', -OPEN ON RESET SUB STA. AND DIESEL CKT. POT. :LOSE0 ON OPERATE
/;;;;\ AUTOMATIC OPERATION
+ MAIN SUPPLY COOLER RESISTANCE HEATER
Re-6 CLOSEO ON PREHEAT fa OPEN ON OPERATE-
40 KVA TRANSFORMER
0-50" AC
COOLER RECTIFIER f y w I20 Y AC V A R I A C
COOLER PREHEAT CONTROL
SELECTOR SWITCH DEVELOPMENT CLUTCH CONTROL CIRCUIT
INORMAL CLUTCH SUPPLV-I PARTIAL CLUTCH
SUPPLY CONTROL CIRCUIT
Fig. 7. E l e c t r i c a l Schematic of Automatic Action Relays.
r.
1
13
UNCLASSIFIED ORNL-LR-DWG 65062
REMOVABLE HEAD ASS E M B LY --
-\
RMANENT LOOP UNTED ASSEMBLY
- - - MAXIMUM - - - - -_ LIQUID LEVEL
MINIMUM LIQUID LEVEL - - - - - - - -
Fig. 8. Cross Section of a Molten-Salt Saqling Device.
14
plug valve i s then opened, and t h e d i p tube i s i n s e r t e d i n t o t h e molten
sa l t i n t h e p m p .
sample i s drawn ap i n t o t h e tube.
b a L plug valve closed.
axount of n o l t e n sa l t whtch car, be removed withot1.t deprimicg t h e pump.
A vacuum i s then app l i ed t o t h e d i p tube, and t h e
The d i p tube i s withdrawn, and t h e
Th? nznber of samplzs is l i m i t , & only by t h e
El',, 3 . . L L J fiow of molter- saLt from t'ne pmip i s past t h e d ra i c - t ank
c o x e c t i o n , tlzrough the f i r s t h e a t e r s ec t ion , tkroJgh a lorig-raaius
182-dSg Surd, t h r o g h C,ke second h z a t e r see-cion, through a c o i l e d
cooler, and back t o t h t pdmp.
yioc:r?ted i n a circular-&Lct a m u i u s through whicn arn'cient a i r i s blown.
To provide t a e rxczss s ry preheat t anpe ra tu re f o r f i l l i n g t h e loop and
f o r p r o t e c t l o n a g a i n s t s o l i d i f i c z t i o n of t h e mol t e r salt i c a n emergency
s i t u a t i o i , t h e coo le r c o i l i s provided idith e l e c t r i c a l hea t ing l u g s a t
both ends and i n t h e cen te r f o r e l e c t r i c a l - r e s i s t a n c e hea t ing . The i n l e t
a_rd o d t l e t &re kep t e t t5.e s a ~ e p o t e n t i a l e l e c t r i c a l l y t o confine t h e
flow of ca-rerrt t o tke c o o h r c o i l oLnly. A sepa ra t e 10-kva s a t u r a b l e
core r e s c t o r a r d t r a r i s f o r w r are connected t o t h e coo le r c o i l f o r use i n
preheat ing c r d x i p g an esnergeacy alarm conditior, .
a t a predeteLrmined rate of approximately 300 axp arid 15 vg and t h e power
i s app l i ed ag tomat i ca l ly m e n r equ i r ed ,
The coo le r s e c t i o n i s a h e l i c a l c o i l
Tke c o n t r o l i s set
Other a u x i l i a r y eq".ipment r equ i r ed f o r t h e ope r s t ion of t h e loop
i x h d e a 3000 cfrr. blower, a cool ing o i l suppiy, an3 t h e necessary u t i l -
i t i e s , sdch as cool i2g aZr f o r t h e frozen-plug vaivz, i n e r t gas, and
cool ing watcr. The e z t i r e p~urp, loop, and d r a i n tank assembly i s shown
i n Fig. 3 mourited on z n o b i l e 3011y f o r ease of f a b r i c a t i o n , inspect ion,
and 5 n s t a L a t i o n .
duct a?d t h e a i r d e f l e c t o r i n t h e center , which f o r m a n annular a i r
passage. Tke back h a l f of t h e coo le r duct i s momted on t h e permanent
s t and f r aze , which also con ta ins t h e c i r c u l a t i n g cool ing o i l system,
h e a t e r concections, and t h e pump-drive motor. Mounted over t h e coo le r
duct i s as i n s u l a t e d cover l i d t h a t i s h e l d i n ar? up r igh t p o s i t i o n by
a solenoid-3eid i a t c h during ope ra t ion of the! loop. I n t h e event of an
a l a r n co%Xtioz which sl?v.ts o f f t h e blower motor, t h e l a t c h i s r e l e a s e d
OK t'ne drop l i d azd erxloses t h e coo le r c o i l t o prevent excessive l o s s
of t ea t .
T2e d s l l y con ta ins one h a l f of t h e i n s u l a t e d coo le r
1 5
4
I
*
Al l c r i t i c a l loop welding i s done by t h e He l i a rc process with i n e r t
cover gas and backup purge according t o a s t r i c t welding s p e c i f i c a t i o n . 7
A l l welds a r e in spec ted v i s u a l l y , by dye penetrant , and by x-ray. Mter
welding, t h e loop i s instrumented with Chromel-Alumel thermocouples and
h e a t e r s .
with shim stock f o r p r o t e c t i o n . Both ceramic- and sheath-type h e a t e r s
are used f o r hea t ing such a u x i l i a r i e s as t h e d r a i n tank, t h e pump bowl,
t h e h e a t e r lugs, acd t h e freeze-plug valve. Standby h e a t e r s are mounted
on t h e loop p ip ing f o r emergency use only i n t h e event of a f a i l u r e of
t h e main power supply.
t h e loop i s covered with 3 i n . of high-temperature i n s u l a t i o n .
and d o l l y assembly are tken i n s t a l l e d i n t h e f a c i l i t y , and t h e connections
are made t o c o n t r o l s and power supp l i e s .
The thermocoiip1.e~ are spot welded t o t h e txbing and covered
After t h e h e a t e r s and thermocouples are at tached,
The loop
Alarm and Automatic-Action Controls
The system thermal i n e r t i a i s low because of t h e small-diameter
tubing used, and t h e r e f o r e safeguards must be provided t o prevent s o l i d i -
f i c a t i o n of t h e salt i n t h e loop. The sa l t i n t h e coo le r c o i l w i l l become
s o l i d i n less than 1 min i f t h e flow i s stopped and no e x t e r n a l h e a t i s
app l i ed .
t e c t t h e loop even though t h e r e w a s a f a i l u r e of t h e power source or any
one p i e c e of operat ing equipment.
An alarm an5 automatic-act ion r e l a y system w a s designed t o pro-
The b a s i c o u t l i n e of t h i s system i s shown i n block form i n F ig . 9. Any one of t he alarms shown a t t h e t o p of Fig. 9, i.e., any cond i t ion
which w i l l cause flow stoppage o r adverse temperatures, w i l l au tomat i ca l ly
p l a c e t h e loop i n an isothermal or safe cond i t ion by performing t h e
a c t i o n s l i s t e d a t t h e bottom of t h e f i g u r e . This r e s u l t s i n t h e e n t i r e
l oop being warmed and i n a safe or isothermal cond i t ion while t h e
necessary a c t i o n i s taken t o r e s t o r e t h e equipment t o operat ing cond i t ion .
To cover t h e p o s s i b i l i t y of t h e f a i l u r e of t h e main power transformer,
t h e ceramic standby h e a t e r s are connected af ter 2 see, and they w i l l
maintain isothermal condi t ions u n t i l t h e main source of power i s r e s t o r e d .
A l l r e l a y a c t i o n s i n d i c a t e d i n t h e block diagram of Fig. 9 are shown
schematical ly i n Fig. 7. The battery-powered r e l a y R-8 i s de-energized
by r e l a y R-4 t o perform t h e f0b.r Pdnctions which p l a c e t h e loop on
LOSS OF NORMAL AND AUXILIARY LOSS OF PUMP CLUTCH SUPPLIES (PUMP STOPS) MOTOR (PUMP STOPS)
INSTANTANEOUS ALARM-ACTION RELAY (NO DELAY IF CONTROL POWER IS AVAILABLE 1
LOOP HIGH LOSS OF MAIN POWER LOOP LOW TEMPERATURE TEMPERATURE SUPPLY TO HEATER SECTION
I I 1 I
DROPS LID ON SWITCHES MAIN POWER SUPPLY FROM OPERATE TO COOLER BOX PREHEAT CONNECTIONS ON LOOP
TIME-DELAY ALARM-ACTION RELAY (2sec DELAY IF CONTROL POWER NOT AVAILABLE TO ALLOW FOR AUTOMATIC THROWOVER I FROM NORMAL TO ALTERNATE FEEDER 1
-
CONNECTS POWER TO COOLER COIL AT PRESET RATE
I CONNECTS POWER TO EMER- GENCY HEATERS ON LOOP I PIPING AT PRESET RATE
Fig. 9. Block Diagram of Automatic A l a r m Actions.
17
isothermal operat ion. To guard a g a i n s t t h e f a i l u r e of t h e power supply t o the b u i l d i n g
which houses t h e tes ts or t o t h e bus duct supplying power t o t h e loops,
equipmect has been designed and i n s t a l l e d as shown i n block diagram i n
Fig. 10. Should a fa i lu i -e occur of t h e normal b u i l d i n g feeder, a t r a n s f e r
t o a n altercate f eede r i s made automatical ly wi th in 2 see. The t ime-delay
relzy TD-1 and r e l a y R-3 of Fig. 7 w i l l ho ld i n t h e battery-powered r e l a y
E-6, al lowing t h e traisfer t o be made without d i s t u r b i n g t h e ope ra t ion of
t h e loops .
pe r iod l o c g e r thap 2 see, t h e emergency d i e s e l generator , which s t a r t e d
imnediately, would begin assuming t h e l o a d through a s e q u e n t i a l t imer.
Loads would be picked i3.p a l t e r n a t e l y between motor s t a r t u p and h e a t e r l o a d
u n t i l t h e e n t i r e f a c i l i t y of 15 loops had power r eapp l i ed w i t h i n 40 see
a f t e r t h e i n t e r r u p t i o n . The 300-kw capac i ty of t h e d i e s e l gene ra to r i s
s u f f i c i e n t t o operate t h e loops i so the rma l ly u n t i l normal b u i l d i n g
e l e c t r i c a l power i s aga in available.
Should t h e bii i lding e l e c t r i c a l power be unavai lable f o r a
Other alarms a r e a v a i l a b l e f o r t h e p r o t e c t i o n of t h e loops t h a t g ive
only an aud ib le o r v i s u a l s i g n a l or both f o r c o r r e c t i v e a c t i o n t o be
taken by t h e ope ra to r .
cool ing o i l flow, l o s s of’ coo le r p rehea t p o t e n t i a l , improper p o s i t i o n of
c o n t r o l switches, improper p o s i t i o n of alarm acknowledge switches, and
loss of c o n t r o l c i r c u i t p o t e n t i a l .
These alarms include l o s s of blower motor, low
Operation and Maintenance of a T e s t Loop
The s t a r t u p of a new co r ros ion t e s t i n g loop i s preceded by a series
of checkouts of equipment.. When a l l t h e e l e c t r i c a l , thermocouple and
c o n t r o l c i r c u i t s are t e s t e d s a t i s f a c t o r i l y and t h e loop i s l e a k t i g h t , t h e
e n t i r e loop i s preheated t o llOO°F with t h e pump s h a f t r o t a t i n g slowly
and t h e cool ing o i l c i r c d a t i n g . The sa l t mixture chosen f o r t h e p a r t i c -
u l a r tes t i s i n t r o d w e d i n t o t h e d r a i n t ank i n a molten state a t a
s l i g h t l y h ighe r tempera tme than t h a t of t h e loop. The d r a i n t ank l e v e l
probe i n d i c a t e s when t h e r e i s s u f f i c i e n t salt t o f i l l t h e loop. I n e r t
gas pressv-re i s admitted t o t h e d r a i n tank and vented from t h e upper
p o r t i o n of t h e loop a t t k e p m p .
18
DIESEL G E N E R AT0 R -- STARTS WHEN POWER FAILS
I 3
SEQUENTIAL TIMER FOR IN- CREMENTAL APPLICATION OF
LOAD
I AUTOMATIC SWITCHING ,
UNCLASSIFIED ORNL-LR-DWG 65069
MANUAL SWITCHING EQUIPMENT
>
I NORMAL BUILDING FEEDER
BUS CUCT
SUPPLYING POWER TO EQUIP- MENT AND CONTROLS FOR 15 LOOPS
ALT E R N AT E BUILDING FEEDER
SUB STATION
SUPPLYING Iio-kva TRANS- FORMER POWER FOR i5 LOOPS
AUXILIARY BUILDING FEEDER
. Fig. 10. Block Diagram of Building Electrical Supply.
,
U
A s t h e sa l t i s slow.ly forced up i n t o t h e loop, i t s path can be
t r a c e d by t h e temperature readings of thermocouples placed along t h e
tub ing .
t h i s l eve l i s maintained by manipulation of gas p re s su re while cool ing
a i r i s suppl ied t o t h e freeze-plug va lve . When t h e temperature of t h e
valve i n d i c a t e s a s o l i d plug, t h e p re s su re i s r e l e a s e d from t h e d r a i n
tank and t h e pump speed :is i nc reased t o begin c i r c u l a t i o n of t h e molten
sal t .
d e s i r e d temperature leve:-. The f i r s t l o a d of sa l t i s c i r c u l a t e d f o r a
minimum of 2 h r t o c l ean t h e system and i s then dumped i n t o t h e d r a i n
tank and removed.
of salt t o be used f o r t h e co r ros ion t e s t .
Level probes i n t h e pump i n d i c a t e when t h e loop i s f u l l , and
Power from t h e mafin t ransformer i s a d j u s t e d t o maintain t h e
The f 3 l i n g ope ra t ion i s repeated with t h e supply
When t h e t e s t sa l t is c i r c u l a t i n g , t h e d i f f e r e n t i a l temperatures
are e s t a b l i s h e d by s h u t t i n g o f f t h e coo le r heat, opening t h e l i d on t h e
coo le r duct, t u r n i n g on t,he blower, c l o s i n g t h e 1 6 0 0 - ~ p h e a t e r s e c t i o n
b reake r (which connects all f o u r h e a t e r l u g s ) , and a d j u s t i n g pump speed,
cool ing a i r flow, and main t ransformer power, as r equ i r ed . When t h e
d e s i r e d cond i t ions are met, a l l t h e c o n t r o l l e r s , alarm se t po in t s , and
automatic func t ion ing r e l a y s are set f o r continuous operat ion.
I n o r d e r t o assure, as far as p r a c t i c a l , t h a t a l l emergency equip-
ment w i l l f u n c t i o n p rope r ly when t h e need arises, a p reven t ive maintenance
program i s c a r r i e d out weekly. A check l i s t i s completed f o r each
f a c i l i t y which c a l l s f o r t h e t e s t i n g of a l l important alarms, t h e throw-
over c i r c u i t on the a u x i l i a r y c lutch supply, t he cooler drop l i d , and
t h e c l u t c h brushes; a v i s u a l i n s p e c t i o n i s made of t h e system.
The tes ts under t h i s program have been operated with maximum w a l l
temperatures of 1200 t o 1500°F, a temperature d i f f e r e n c e between t h e
maximum w a l l temperature and t h e m i n i m u m f l u i d temperature of 200 F, and
flow rates up t o 3 gpm.
p e r a t u r e s of 1500°F and h ighe r .8
l i m i t e d only by t h e s t r e n g t h of t h e con ta ine r material used. The tem-
p e r a t u r e d i f f e r e n t i a l obtained i s l imi ted by t h e flow rate and power
a v a i l a b l e . The f o r c e d - c i r c u l a t i o n co r ros ion t e s t f a c i l i t y with eleven
t e s t s t ands showing i n t h e l e f t background i s p i c t u r e d i n Fig. 11. The
remaining f o u r t e s t s t ands are on t h e opposi te s i d e of t h e a is le t o t h e
r i g h t .
0
Previously tes ts were conducted with w a l l t e m -
The w a l l temperatures obtained are
20
I
b
21
Summary
Twenty-five loops hsve been f a b r i c a t e d with both INOR-8 and Incone19
and have operated under t h i s program f o r an accumulated t o t a l of over
29O,OOO h r . Twenty of t h e loops, t h i r t e e n of which were f a b r i c a t e d of
INOR-8 and seven of Inconel, operated from one t o two and a ha l f years
before being terminated 2nd examined meta l lographica l ly .
The long-term operat ion and metallographic examination of t hese
loops w a s inst rumental i n t h e acceptance of INOR-8 as t h e conta iner
material f o r t h e Molten ;Salt Reactor Experiment.lo
i s expected t o be less than 1 mils /yr a t t h e design opera t ing temperature
of 1225'F.
The expected corrosion
Corrosion specimen weight loss and salt sample d a t a from t h e s e loops
ind ica t ed t h a t t h e primary cor ros ion product i s chromium and t h a t an
e s s e n t i a l l y cons tan t value w a s achieved af ter approximately 5000 h r of
o p e r a t i o n . l l
Acknowledgments
Many persons have made important con t r ibu t ions t o t h e design and
opera t ion of t hese f a c i l i t i e s .
H. W . Savage under whose d i r e c t i o n t h i s program w a s executed. The suc-
c e s s f u l opera t ion of t hese loops w a s due t o a l a r g e ex ten t t o
W . H. Duckworth and t h e s h i f t operat ions group under R. Helton, and t o
many o the r s t o o numerous t o mention.
Acknowledgment i s made e s p e c i a l l y t o
22
R e f e r e ne e s
1. J. H . &Van and
2 .
3 "
4.
5.
6.
7.
8.
9.
10 *
11.
J . D. Man S a l t Mixtures, Trans. Am.
y, Corrosion P rope r t i e s of Fused-Fluoride Nuclear Soc., 1 (1) :44 (June 1958).
D. E. Trauger a i d J . A. CorLLin, CircLllat.ing Bused-Salt-Fuel l r r a d l a t i o n T e s t Loop, Trans. Am. Nuclear Soc., 2 (1):173-4 (CTi;.De 1959).
5. ?. Biake ly , Molten S e l t Coxpositions, Oak 3idge National Laboratory Report C F - 5 8 - 6 - m J u n e 12 , 1958).
J . 3. Keyes and A. I . Krakoviak, High-Frequency Surface Thermal F a t 1 Trans. Am. NLlclear Soc., r l ) : 2 2 - & (June 1959).
W . F. Boudre~~i., A, 5. G r i ~ d ~ 2 . L and H. W . Savage, Tlze Development and Operation of Cantrifug8.l P w p s f o r Liquid Metals 2nd Fused S a l t s a t l100-150G°F, Trans. AT. Nuclear Soc . , 2 (1) :l7-l.8 (June 1959).
W. B. McDonald a i d J. L. Crowley, A Samplin Device f o r Molten S a l t Systems, Oak Ridge Rat ional Laboratory Report \8 ORNL-2 (March 7,1960)
'i'. 3 . Housley apd 2. Pa t r i a rca , Procedure Spec i f i ca t ioL - PS-2 f o r D.C. AFX Weifiins of - l n c o n e l Tubing f o r Higk! I Corrosion 4-pplications, Oak Ridge Eat ions1 Lcboratory.
W . D. Manly -_ e t hl., - ?i le ta l lsrgical P rob lem i n Molten Fluoride Systems, Proceedirgs of t h e SGcond United Nations I n t e r n s t i o n a l Conference on t h e Peaceful Uses of Atomic Energy, Vol. 7, pp. 223-34, United r\Tatlozls, Geneva, 1958.
J. A. Lane, ?. G . bkcPhersori and F. Maslar?, F lu id Fuel Reactors, p . 596, Addisoi-We.cle;r, Reading, Mass., 19587
S. E. Beail e t -- &lo, Moit?n-Sal t Reactor Experiment Prel iminary Hazards Report, Ozk 3idge NLtioral Laboratory Report CF-62-2-46 (Feb. 28, 2.961).
J. E. &'an and R . E . Evans III, Corrosion Bzhavior of Reactor Materials ir F ~ u o ~ c ! . ~ S a l t Mi x tu res Oak Ridge National Laboratory Repo-ct TX-329 (Septenber 19, ---, 19 2
I \ ' d i
c
23
DISTRIBUTION I
1. MSRP D i r e c t o r ' s Office 43. W . B. McDonald 2. G . M. Adamson 3. L. G . Alexander 4. S. E. Bea l l 5. M . Bender 6. E. S. B e t t i s 7. F. F. Blankenship 8. E. G . Bohlmain 9. D. L. Clark
10. J . A. Conlin 11. W . H. Cook
lZ.-l5. J. L . Crowley 16. J. H . DeVan 17. R . G . Donnelly 18. J. R. Engel 19. C . H . Gabbard 20. R . B. Gal laher 21. W . R. Grimes 2 2 . A. G . Gr inde l l 23. R . H . Guymon 24. P. H . Harley 25. P. N. Haubenreich 26. R . Helton 27. E. C . Hise 28. H. W . Hoffman 29. P. P . Holz 30. T. L . Hudson 31. R . J. K e d l 32. J. J. Keyes, Jr. 33. S. S. Kirslis 34. A. I . Krakoviak 35. J. W . Krewson 36. J. A. Lane 37. E. M. Lees 38. R . B. Lindauer 39. M . I . Lundin 40. R . N. Lyon 41. H. G . MacPherson 42. E. R . Mann
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H. F. McDuffie C . K. McGlothlan R . L . Moore J. C . Moyers W . R . Osborn P. P a t r i a r c a H. R . Payne M. Richardson R. C . Robertson H. W . Savage A. W . Savolainen D. S c o t t J . H. Sha f fe r M. J. Skinner G. M. Slaughter A. N. Smith P. G . Smith I. Spiewak J. A. Swartout A. Taboada J. R . Tallackson R . E. Thoma D. B. Trauger W . C . U l r i c h C . F. Weaver B. H. Webster A. M. Weinberg J. C. White L . V. Wilson Cen. Res. Lib. (CRL) Doc. Ref. See. (DRS) Lab. Records (LRD) Lab. Records - RC Div. of Tech. I n f o . Exten. Res. and Dev. Div. (ORO) Reactor Div. (ORO) ORNL Pa ten t Off ice
External
110.-111. D. F. Cope, Reactor Div., AEC, OR0 112. A. W . Larson, Reactor Div., AEC, OR0 113. H. M. Roth, Div. of R e s . and Dev., AEC, OR0 114. W . L. Smalley, Reactor Div., AEC, OR0 115. J. Wett, AEC, Washington