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ORNL-TM-4804.txt
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e ~1729 %
ORNL-TM-4804
A Method for Calculating the
Steady-State Distribution of Tritium
in a Molten-Salt Breeder Reactor Plant
R. B. Briggs
C. W. Nestor
OPERATED BY UNION CARBIDE CORPORATION = FOR THE U.S. ATOMIC ENERGY COMMISSION
Printed in the United States of America. Available from
National Technical Information Service
U.S. Department of Commerce
5285 Port Royal Road, Springfield, Virginia 22161
Price: Printed Copy $5.45; Microfiche $2.25
This report was prepared as an account of werk sponsored by the United States
Government. Neither the United States nor the Energy Research and Development
Administration, nor any of their employees, nor any of their contractors,
subcontractors, or their employees, makes any warranty, express or implied, or
assumes any legal liability or responsibility for the accuracy, completeness or
usefulness of any information, apparatus, product or process disclosed, or represents
that its use would neot infringe privately owned rights.
ORNL-TM-4804
UC-76 — Molten Salt
Reactor Technology
Contract No. W-7405-eng-26
Reactor Division
A METHOD FOR CALCULATING THE STEADY-STATE DISTRIBUTION
OF TRITIUM IN A MOLTEN~-SALT BREEDER REACTOR PLANT
R. B. Briggs
Central Management Office
C. W. Nestor
Computer Sciences Division
NOTICE
This report was prepared as an account of work
sponsored by the United States Government. Neither
the United States nor the United States Energy
Research and Development Administration, nor any of
theit employees, nor any of their c¢ontractors,
APR‘ L ]975 subcontractors, or tpeir ) employees, makes any
warranty, express or implied, or assumes any legal
liability or responsibility for the accuracy, completeness
or usefulness of any information, apparatus, product or
process disclosed, or represents that its use would not
infringe privately owned rights,
OAK RIDGE NATIONAL LABORATORY :$
Oak Ridge, Tennessee 37830
operated by
UNION CARBIDE CORPORATION
for the
U.S. ENERGY RESEARCH AND DEVELOPMENT ADMINISTRATION
prare mAanUAENT UNLIMITE
DISTRIBUTION OF THIS DOCUMERS 7 1}[
i !
iii
CONTENTS
Abs tract * s . . . . L4 . L * - * - * * . - *
I. Introduction . L] ° . *® . e . - * . - - *
IT. Derivation of Equations and Computational Procedures
ITI. Solution of Equations . .« « &« « « o &
IV. Nomenclature . « « ¢ o o« o s o o o o o
V. Computer Program, Input Instructions and
Appendix — Program Listing . ¢« o« ¢« ¢ o ¢ o &
o * * * - . .
23
35
49
65
LIST OF FIGURES
Fig. 1. Molten-Salt Breeder Reactor System. . . . . .
Fig. 2. Sketch Of F(CK) VS CK . o - L ] L ] . . * . L * *
Fig. 3. Sketch of G(C,) VS8 C, « « & o« « s s o o o o &
K K
Fig. 4. Sample Problem Input .« « o o ¢ ¢ « o o o o &
Fig. 5A. List of Parameter Values Used in Calculation
Fig. 5B. Output from Iterative Calculations . . . . .
Figo SC. Output Sumary e & ® e+ & * % ® & 5 & & s s @
Fig. 5D. Output Produced by "CHANGE" Command. . . . &
Fig. 5E. List of Parameter Values Used in Calculation
"CHANGE" Command. « o « o o o o -6 o ¢ ¢ o o o o s o
Fig. 5F. Output from Iterative Calculations With New Parameters
Fig. 5G. Output Summary (New Parameters). « o« o « o« o s o o o o
Fig. 5H. Response to Unrecognized Command Card. « « « ¢« ¢« « « o
Fig. 5I. Normal Ending Message. . « « ¢ s o ¢ ¢ & o &
After
27
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33
55
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58
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63
A METHOD FOR CALCULATING THE STEADY-STATE DISTRIBUTION
OF TRITIUM IN A MOLTEN-SALT BREEDER REACTOR PLANT
R. B. Briggs and C. W. Nestor, Jr.
ABSTRACT
Tritium is produced in molten salt reactors primarily by fissioning
of uranium and absorption of neutrons by the constituents of the fuel
carrier salt. At the operating temperature of a large power reactor,
tritium is expected to diffuse from the primary system through pipe and
vessel walls to the surroundings and through heat exchanger tubes into
the secondary system which contains a coolant salt. Some tritium will
pass from thé secondary system into the steam power system. This report
describes a method for calculating the steady state distribution of
tritium in a molten salt reactor plant and a computer program for making
the calculations. The method takes into account the effects of various
processes for removing tritium, the addition of hydrogen or hydrogenous
compounds to the primary and secondary systems, and the chemistry of
uranium in the fuel salt. Sample calculations indicate that 30 percent
or more of the tritium might reach the steam system in a large power
reactor unless special measures are taken to confine the tritium.
I. INTRODUCTION
Conceptual designs of Molten Salt Breeder Reactor (MSBR) power
plants usually can be represented by the diagram shown in Fig. 1. The
fissioning of uranium in the fuel salt heats the salt as it is pumped
through the reactor vessel in the primary system. The heat is trans-
ferred to a coolant salt that circulates in the secondary system and,
thence, to water, producing steam to drive a turbine-generator in the
steam system.
Fission products and other radiocactive materials are produced in
large amounts in the fuel salt. Much smaller amounts are produced in
the coolant salt by the flux of delayed neutrons in the primary heat
exchangers. The radioactivity is normally confined by the 'walls of
the piping and vessels. However, tritium is produced in the salts,
partly as a fission product, but mostly by absorption of neutrons by
lithium in the fuel salt. At the high temperature of an MSBR, tritium
diffuses through metals and might escape to the environs in amounts
thgt would be cause for concern.
The purpose of this report is to describe a method for calculating
the distribution of tritium in and its escape from an MSBR plant. We
assume that the tritium, born as tritium ions, is present in the fuel
salt primarily as tritium molecules® and tritium fluoride molecules. ¥
The ions are estimated to be produced at a rate of 2.6 X lOlh/MWsec***
*Tritium molecules are intended to include HT and H, molecules
when hydrogen is present.
*%Tritium fluoride molecules are intended to include tritium (and
hydrogen) ions associated with fluoride ions in the salt.
**%2420 Ci/day in a 2250 MW(t), 1000 MW(e) plant.
ORNL-DWG 68~1185EB
PURGE STREAM PURGE STREAM
FOR REMOVAL OF TRITIUM FOR REMOVAL OF TRITIUM
—~ FROM FUEL SALT FROM COOLANT SALT
) A
PRIMARY SECONDARY
SALT PUMP NaBFy—NaF SALT PUMP
1
COOLANT SALT
11150 °F
{300°F wp
GRAPHITE
MODERATOR
REACTOR
HEAT _
EXCHANGER Hi
1050 °F €W
TLiF -BeF,-ThFy-UF, STEAM GENERATOR
FUEL SALY SUPERHEATER, AND
—-— A T
1000 °F '
——
TURBO-
GENERATOR | L—==
STEAM
Fig. 1. Molten Salt Breeder Reactor System.
in a typical fuel salt. The relative concentrations of tritium and
tritium fluoride in the fuel salt are expected to be governed by the
equilibrium relationship for the reaction,
UF, + 1/2 T, 2 UF3 + TF ,
with uranium in the salt. The absolute concentrations are governed
by removal processes.
Three types of processes are provided for removing tritium from
the primary system: permeation through the metal of the walls of
piping and vessels, sorption on materials in contact with the salt,
and purging. We assume that tritium molecules that reach a metal
surface can sorb on the surface, dissociate into tritium atoms and
diffuse through the metal. Tritium in tritium fluoride and other
compounds is assumed to be chemically bound and unable to pass through
the metal.
Experience with the Molten Salt Reactor Experiment indicated that
tritium sorbs on and is tightly bound to graphite. We provide for
sorption of tritium and tritium fluoride on the graphite in the reactor
core.
Provision is made for purging tritium from the primary system by
circulating a stream of salt through an apparatus which extracts gaseous
tritium and tritium compounds. A contactor in which tritium and tritium
fluoride are transferred to a gas phase by virtue of their wvapor
pressures would be such an apparatus. Current designs for MSBR's
provide for sparging c¢f the fuel salt with helium bubbles in the
primary system to remove krypton and Xenon. Tritium and tritium
fluoride would be removed also. The sparging process can be treated
as an equivalent purging process in the calculatioms.
Tritium will reach the secondary system by diffusion from the primary
system through the walls of the tubes in the primary heat exchangers
and by neutron capture in the coolant salt. We provide for removal of
tritium from the secondary system by diffusion through the metal walls,
sorption, and purging. The secondary system would not normally contain
a sorber or have an elaborate purging system. Such processes, if
incorporated into the plant, would be designed specifically for removing
tritium.
The coolant salts do not normally contain constituents that are
reducible by tritium and, thereby, able to convert tritium into tritium
fluoride and make it unavailable to diffuse through the metal walls.
We, therefore, have provided for addition of hydrogen fluoride or other
hydrogenous compounds to the secondary system. We assume that tritium
will exchange with the hydrogen in the added compound and that the
compound will be extracted by the sorption and/or purge process.
The steam system and the cells around the reactor primary and
secondary systems are considered to be sinks for tritium. Tritium
reaching the steam system is assumed to exchange with hydrogen in the
water, and thdat reaching the cells is assumed to be oxidized to water.
The partial pressure of tritium is effectively zero.
In the calculations we assume that tritium and hydrogen behave
identically. The equation used for calculating the diffusion of
hydrogen through a metal wall states that the rate of transport per
unit of surface area is proportional to the product of a permeability
coefficient and the difference between the square roots of the partial
pressures of hydrogen at the inner and outer surfaces of the metal.
In this circumstance, addition of hydrogen can reduce the transport
of tritium through the metal. Suppose, for example, the partial
pressures of tritium and hydrogen at the outer surface of a pipe are
zero and the partial pressure of tritium at the inner surface is held
constant. If hydrogen were added to increase the total hydrogen partial
pressure at the inner surface by a factor of 100, the flow of hydrogen
plus tritium through the metal wall would increase by a factor of 10.
But the flow of tritium would decrease by a factor of 10 because of the
100-fold dilution of hydrogen. Because of other factors, the effect of
adding hydrogen may not be so dramatic, but the calculational method
provides for addition of hydrogen to the primary and secondary systems
and for hydrogen to be present at a specified concentration in the
steam system so that the effects can be studied.*
The calculational model describes the behavior of tritium in an
MSBR plant to the extent that it is known or has been inferred at the
present time. The removal processes can be included in or eliminated
from the calculations by careful choice of the values assigned to co-
efficients in the equations. The model probably does not include all
the chemical reactions and physical processes that will ultimately be
*The calculational procedure might have been developed to treat hydrogen
and tritium as separate species. Separate values then could be assigned
to important parameters, such as solubility and diffusion coefficients,
for each species. Interaction between hydrogen and tritium would be
taken into account by the equilibrium relationship
péT/pHQ *Pp, = kp for the reaction H, + T, ¥ HT .
However, kp has a value near 4 at temperatures of interest, which signi-
fies that hydrogen and tritium interact as though they are the same
species. Also, there are substantial uncertainties in the values for
most of the parameters. Complicating the procedure to treat hydrogen
and tritium separately would not, for the present, improve the accuracy
of the results.
shown to affect the distribution of tritium in an MSBR. In some
instances these effects can be included, when recognized, simply by
adjusting the coefficients in equations for processes presently in-
cluded. Others may require incorporation of additional processes.
Two assumptions in the calculational procedure should be recognized
for their potential for leading to major differences between the cal-
culated distribution of tritium and what would actually occur in a
reactor plant. Tritium, present in the salt as tritium fluoride, can
react with metal to yield tritium atoms that would dissolve in and
diffuse through the metal. Neglect of this reaction could cause the
calculations to be greatly in error under circumstances where most of
the tritium is present in the salt as tritium fluoride.
Oxide films (and possibly others) that form on metal surfaces
reduce the permeability of a metal wall to the passage of hydrogen.
They may also cause the transport to vary with pressure to a power
in the range of 1/2 to 1. The reduced permeability appears as a
coefficient in the transport equations of the model, but we make
no provision for changing the exponent on the pressure terms from
1/2. The calculated transport of tritium through the metal walls
and the effect of the addition of hydrogen in reducing the transport
would both be greater than would actually occur if the actual trans-
port were proportional to the pressure to a power in the range 1/2
to 1. The calculations would not underestimate the transport unless
the total pressure of tritium and hydrogen exceeded the reference
pressure for the permeability coefficient, which is usually 1 atm.
II. DERIVATION OF EQUATIONS AND COMPUTATIONAL PROCEDURES
In making the calculations, we first calculate the distribution of
hydrogen plus tritium in order to establish flows and concentrations of
the combined isotopes throughout the plant. Then we calculate the distri-
bution of tritium throughout the plant.
For calculating the distribution, the fluids in the primary and
secondary systems and the various parts of the steam system are assumed
to be well mixed and to contain uniform bulk concentrations of all
constituents, The calculations are for steady-state conditions, and
only hydrogen and tritium molecules are assumed to be able to sorb on
the metal surfaces, dissociate, and diffuse through the metal walls.
The various paths are defined and the distribution is calculated by the
use of the following set of equations.*
A. In the primary system:
1. Transport of hydrogen through the salt film to the wall
of the piping in the hot leg from the reactor vessel to
the heat exchanger:
Q1 = h1A1(CF — C1) (1a)
Transport through the pipe wall to the surroundings where
the hydrogen pressure is assumed to be negligible:
- p1A1 [(kl_cl)? _— 0] - RJLAI (klcl).r . (1b)
Qi ty t,
2. Transport of hydrogen to and through the walls of the cold-
leg piping from the heat exchanger to the reactor vessel:
*Symbols are defined in Section IV, Nomenclature.
10
Q2 = thz(CF - C3z) (2a)
1
5
- EzAziszz) . (2b)
Transport of hydrogen to and through the walls of the
reactor vessel and the shells of the heat exchangers in
the primary system:
Qs = hsAs(Cp — Ca) (3a)
z
- EaA:(kSCB) (3b)
3
Transport of hydrogen to and through the walls of the
tubes in the primary heat exchangers into the secondary
system:
Qe = haAa(CF'“ Ca) (4a)
Puhs + z
= . [(kacu) = (k12C12) ] . (4b)
Transport of hydrogen to the surfaces of the graphite
in the reactor vessel or to other sorber:
Q5 = h5A5(CF - Cs) . (Sa)
Sorption by the graphite or other sorber assuming that
the sorbing surface is replaced continuously and that
the concentration of sorbed gas is proportional to the
square root of the partial pressure:
+
Qs = B;W,As (ksCs) . (5b)
Removal of hydrogen by purge:
Qe = F1E1CF . (6)
11
7. Transport of hydrogen fluoride to and removal by sorber:
Q; = h7A7(CFF'“ Cs) (7a)
1
B,W.A, (k,Cy)~ . (7b)
8. Removal of hydrogen fluoride by purge:
Qs = FLE;C . (8)
FF
Because the molecular species involved may contain different numbers
of hydrogen atoms, all the calculations are done in terms of atoms of
hydrogen. This does not mean that the hydrogen necessarily diffuses as
single atoms, but only that a transport unit is one hydrogen atom and
the parameters are expressed in terms of single hydrogen atoms. A
Q value of 1 then represents the transport of one-half molecule of H,,
one molecule of HF, or one-fourth molecule of a compound 1like CH,, all per
unit time. Likewise, a C value of 1 represents a concentration of one-
half molecule of H,, one molecule of HF, or one-~fourth molecule of CH,,
all per unit volume.
If the rates of inflow of tritium and hydrogen atoms (R; and R,,
respectively) to the primary system are given, a material balance over
the primary system gives
8
R; + R = I Q. (9)
i=1 *
In our calculations, all flow rates in the sum on the right-hand side
of Eq. 9 are positive or zero except for Q,, the transport through the
12
heat exchanger tubes to the secondary system. Q, can be positive,
negative or zero, depending on the conditions in the various systems.
Hydrogen is present in and is removed from the primary system as hydrogen
fluoride, but we provide no input of HF. It is produced by the reaction
UF, + +H, < UF, + HF ,
which has an equilibrium quotient
X(UFs) _BPAER)
XUR) [P (Ha) ]
or
X(UFy) | “7“rF 1
Corrosion and other chemical considerations make it desirable to maintain
the ratio X(UF5)/X(UF,) = 1/U at a constant value,* so the concentration
of HF in the bulk of the salt can be related to the hydrogen concentration
by
2
Cop = -11\-{{-{71 (ksCp)? . (10)
We replace CFF by the equivalent function of C_, in Eqs. 7a and 8 to obtain
F
expressions for @, and Qg in terms of CF'
B. Secondary System:
1. Hot-leg piping:
Qio0 = thAlO(CC — C10) (11a)
1
- Piohio (kloclo)f . (11b)
Cio
#This might require that hydrogen be added to the primary systems as
a mixture of hydrogen and hydrogen fluoride.
13
Cold-leg piping:
Q11 = hy1An, (CC - C11)
= EA%ALL (k110111%
11
Transport through the primary heat exchanger tubes into the
primary system:
Qrz = hi24y (C. - Ci2)
| 1
= %‘?‘u‘[(kmczz)f - (kuCu)T] .
Transport through the steam generator tubes into the
Steam system:
Qi3 = hi3A;; (CC - C13)
A 1 1
= P‘%?—Bl—i [(k13€13)7 - (RZICZI)TJ .
Transport through the superheater tubes into the steam
system:
Qiy = hitAqy (CC - C1y)
A 1
= R‘l—‘l&i [(kmcm)%" (kzzczz)r] .
Transport through the reheater tubes into the steam system:
Q15 = hisA;s (CC - C15)
1
P‘uti\—;i [(kzsCls)% ~ (k23C2 3)7] .
Removal by sorber as hydrogen:
Q16 = higAis (CC - Cig)
1
B3WsA16(k16C1g)° .
(12a)
(12b)
(13a)
(13b)
(14a)
(14b)
(15a)
(15b)
(16a)
(16b)
(17a)
(17b)
14
8. Removal by purge as hydrogen:
Qir = FSEBCC . (18)
9. Removal by sorber as HF:
Qis = h1eA1a(CCF — C1s) (19a)
1
BuWuhia(kisCia) > - (19b)
10, Removal by purge as HF:
ng = FqEqC . (20)
CF
Since we assume that the hydrogen fluoride does not release hydrogen
to diffuse through the metal walls, and that there are no chemical reac-
tions in the secondary system that make the concentrations of hydrogen and
hydrogen fluoride interdependent, we write separate material balances for
the two species for the distribution of total tritium and hydrogen:
17
Rs + Ry = I Q (21a)
i=10
Rs = Q18 + Q1o -« (21b)
In these equations all the R's and all the Q's have positive or
zero values except for Qi2, Qi3, Q14 and Q;s5, which can have negative
values.
C. Steam generator system:
1. Transport through the steam generator tubes into the secondary
system:
Q1 = h21A13(CSG -~ Cz1) (22a)
A 1 1
= E'l—ta‘*z—s‘[(kzlcz D7 - (&, 3C13)7] . (22b)
13
2. Transport through superheater tubes into the secondary system:
Qz2 = hzzAlu(CSS - Cz2) (23a)
15
A 1 1
= E‘l'i';:i [(kzzczz)z_ - (klucw)?] . (23b)
3. Transport through the reheater tubes into the secondary system:
Q23 = hz3A15(Cop = C23) (24a)
A 1 1
= PJ‘f:—lji [(kzaczs)r - (kzscls)y] . (24b)
and C_._ will be given.
I
n the steam system the values for CSG’ CSS SR
The steam flows will be so large that the diffusion of hydrogen through
the metals should not have much effect on the concentration of hydrogen
in the steam. Under these assumptions, we do not require a material
balance over the steam system. If hydrogen is added to the feed water
as hydrazine or in some other manner to give a specified ratio of
hydrogen to H,0, then this ratio, coupled with the steam tables, can be
used to calculate the hydrogen concentrations in the water and steam in
the steam-raising equipment. Without addition of hydrogen the
concentrations are established by the dissociation of water.
We now need to solve the above equations to obtain values for all
the flow rates and concentrations. We carry this out in the following
sequence, discussed in more detail in Sec. IIIL.
1. Calculate C Cis, Q18 and Q;9 from equations 19a, 19b, 20
and 21b.
CF’
2. Assume a value for CC.
3. Calculate Qip5, Q115 Qi15, Q17 and C;¢ from equations 1lla, 11b,
12a, 12b, 17a, 17b and 18.
4. Calculate Qi13, Qis, Qis, Ci13, Ciy and Ci1s from equations léa,
14b, 15a, 15b, 16a, 1l6b, 22a, 22b, 23a, 23b, 24a and 24b,
noting that the steam system and the secondary system are
coupled by the relationships Qi3 = -Q21, Q14 = -Qz22 and
Qis = —Q23.
16
5. Calculate Q;, from the material balance, Eq. 2la.
6. Calculate CF’ Ci12 and Cy from Eqs. 4a, 4b, 13a, 13b, the
relationship Q4 = -Q;» and the value of Qi» obtained in step 5.
These concentrations should all be positive. If any one of them
is negative, steps 3 through 6 must be repeated with a larger
value of CC.
7. When positive values have been found for CF’ Ci2 and Cy4,
calculate Qi, Q2, Q3,5 Qs Q65 Q7,5 Qss Cs, Cpp and Cy.
8. Calculate RF from
8
Rp = iil Qi - (R; + Rp) &
If RF is positive, hydrogen must be added to the primary system
in order to maintain a balance. This means that CF is too large,
which in turn means that CC is too large, and steps 3 through 8§
must be repeated with a smaller value of CC. If RF is negative,
CC is too small and steps 3 through 8 must be repeated with a
larger value of CC.
When this process has been repeated until the ratio is
R, + R,
sufficiently small, the flows and concentrations of hydrogen plus tritium
and of hydrogen fluoride plus tritium fluoride have been established
throughout the plant and we can proceed with the calculation of the
tritium distribution. We ignore the difference in the properties of
the two isotopes and assume that they behave identically. Thus,
hydrogen and tritium compounds have the same solubilities and
diffusivities, and if a hydrogenous compound, such as HF, is added
to a mixture of hydrogen and tritium, exchange will occur to give a
ratio of tritium to hydrogen that is the same in hydrogen* and the
added compound.
*H,, HT and T,.
17
We now proceed with the calculation of the tritium distribution.
D. Primary system:
1. Transport through walls of hot-leg piping:
Qs1 = UFT Q; . (25)
“r
2. Transport through walls of cold-leg piping:
Q32 = EEI Q2 . (26)
“r
3. Transport through wall of reactor vessel and shells of heat
exchangers in primary system:
Q33 = _FT Q3 . (27)
4, Transport through walls of primary heat-exchanger tubes
into the secondary system:
Qay = hyA,y (CFT - Cay) (28a)
il
B [decsr ~ osery| - (260)
Equations 25 through 27 are straightforward, simply indicating that
the amount of tritium flowing with hydrogen is proportional to the fraction
of the concentration that is tritium when the flow of both is into a sink
with a zero concentration of both. Equation 28a is straightforward,
indicating that the flow of tritium from the bulk salt to the wall is
proportional to the difference between the concentrations of tritium in
the bulk fluid and the wall. Equation 28b, however, requires some
additional explanation.
18
The rate of transport of hydrogen through a metal wall can be
expressed as
I) .
_DA v _
Q= t (CI Co
where D is the diffusivity of hydrogen atoms in the metal, the C's are
the concentrations of hydrogen atoms dissolved in the metal at the inner
(I) and outer (0) surfaces, t is the metal thickness and A is the surface
area. Assuming no interaction of tritium and hydrogen atoms as they
diffuse through the metal, the rate of transport of tritium is
_DA
QT t
¥ t
- C .
(o 0
The concentration of hydrogen + tritium atoms in the metal at the
surface is
1
¢ = s = so)?
where S is a solubility coefficient and P is the partial pressure of
hydrogen + tritium and is equal to the product of Henry's law coefficient
and the concentration of hydrogen + tritium in the salt at the surface.
Assuming that the ratio of tritium to hydrogen + tritium in the metal
at the surface is the same as that in the salt at the surface, we can
write
v — CTI — %-CTI kICTI
C —C————S(kC) _.._._.=S_..._.._.1.
TI T C I'T” C | s
I 1 (kICI)
and a similar expression for the outer surface. Then,
kiCr kqCro
1 = 1
(kICI)f- (kOCOy?
_ DSA
U = 7%
19
and by substituting the permeability coefficient, p, for the product,
DS, we obtain Eq. 28b. This treatment is necessary here because
the net flows of hydrogen and tritium may be in opposite directionms.
The equations provide a means for taking into account the effect of the
mass action laws on the concentrations of tritium in the metal and its
transport through the metal.
5. Removal by graphite or other sorber:
C
FT
Q35 = T Qs » (29)
F
6. Removal by purge:
C
FT
Q3 = Rl Qg (30)
F
7. Removal by graphite or other sorber as tritium fluoride:
CFT
Q37 = = Q7 , (31)
Cr
8. Removal by purge as tritium fluoride:
C
Qag = EEE'QB . (32)
7 :
The tritium balance over the primary system is:
38
Rl = 2 Qi . (33)
i=31
E. Secondary system:
1. Hot-leg piping:
C
CT
Quo = ¢ Qo - (34)
20
2. Cold-leg piping:
C
CT
Qui =5 Q1 (35)
C
3. Transport through primary heat exchanger tube walls into
primary system:
Quz = R128u(Cop = Cuz) (36a)
= -E-li-l}-ii _klz_C"f_z__' - kquq v .
ty [(klzclz)’f (kaCoa)i | (36b)
4. Transport through steam generator tube walls into the steam
system:
Qus = h13A13(CCT ~ Cy3) (37a)
_ P13Ais klgcual
tiy (ki13Ci3f2
. (37b)
Calculations of the tritium distribution are based on the assumption
that tritium will exchange so rapidly with the hydrogen in the steam to
form tritiated water that the tritium concentration will be effectively
Zero.
5. Transport through the superheater tubes into the steam system:
Quy = hluAlu(CCT - Cuy) (38a)
_ PauAyy _kiuCuy
= 1 . 8b
tiv (ki14C1y)7 (38b)