Oxidation of tritium in packed bed of noble metal catalyst for detritiation from system gases

Journal

of Nuclear Materials North-Holland. Amsterdam

135 (1985) l-10

OXIDATION OF TRITIUM IN PACKED BED OF NOBLE DETRITIATION FROM SYSTEM GASES Masabumi NISHIKAWA, Mikio ENOEDA Department Received

Toshiharu

TAKEISHI,

METAL

CATALYST

Kenzo MUNAKATA,

Kenji

FOR

KOTOH

and

of Nuclear Engineering, Kyushu lJniversit.v, Hakozaki. Higashi - ku, Fukuoka 812, Japan

30 August

1984; accepted

6 April 1985

Catalytic oxidation rates of tritium in the bed of the noble metal catalysts are obtained and compared with the oxidation rates observed for the packed bed of spongy copper oxide or hopcalites. Use of Pt- or Pd-alumina catalysts is recommended in this study because they give effective oxidation rates of tritium in the ambient temperature range. The adsorption performance of tritiated water in the catalyst bed is also discussed.

1. Introduction A multi-barrier containment concept will be applied to control tritium in a fusion power plant. The rationale for this concept is the prevention of the dilution of concentration in each barrier so that the tritium can be recovered before it penetrates to the outer barrier. Tritium cocentration of more than tens of thousands ppm will be handled in the primary containment which consists of the equipments and pipes to enclose the tritium bearing materials in the plasma fuel and exhaust system, the breading blanket system and the fuel processing system. It has been reported by Kuroki et al. [l] that almost all tritium in the plasma exhaust gas should be recovered for use to keep the self sustained plasma when only the bred tritium is supplied. Nishikawa et al. [2] have recommended to handle tritium in the oxide form for this purpose. As nearly all of the primary containment system will be enclosed in a secondary containment .with an inert gas atmosphere, tritium of a rather low concentration is handled in the secondary containment system under the steady state operation, while tritium of high concentration should be dealt with in case when some troubles happen with the primary containment system. Gloveboxes are used for the secondary containment. The reactor building serves as the tertiary containment and an emergency cleanup system will recover tritium from the room air to minimize the environmental release of tritium. Application of the catalytic oxidation operation is considered to handle tritium in each containment system as reported by Kershner [3] and Ortman et al. [4].

0022-3115/85/$03.30 0 Elsevier Science Publishers (North-Holland Physics Publishing Division)

However, detailed pre-examinations are needed to select the most suitable operational conditions to each tritium handling system becasue of a wide variety in concentration of tritium or hydrogen isotopes, gas components accompanying with tritium, chemical form of the tritium bearing materials, gas flow rate, pressure and temperature. In this paper, catalytic oxidation rates of hydrogen isotopes in the bed of noble metal catalyst are discussed and compared with the oxidation rates observed for the packed bed of spongy copper oxide or hopcalites reported elsewhere by the present authors [5,6]. Effects of gas flow rate and bed temperature on the overall oxidation rate are also discussed.

2. Theory The tritium balance following equations: Vn(dC~n.n,rn/df)

=

in each enclosure

&H,D,T,T

-

-

Q~~H.D.T,T

’

c1 -

is given by the

&H.D.T,T

C~H,D,T)T.~/C~H.D.T)T

-P~(CO,D,T~)~ b@C&.D,T)To/df)

=

R(H,D,T,TO

(1) -

-

Q~~H.D.T)To

’

(I

-

&H,D,T,TO

C~H.D.T)TO.~~C~H.D.T)TO

-P’~(C~H,D.T,TO).

B.V.

1

1 (2)

where VE. t. R. q and Q mean volume of the enclosure. time, teak rate from the inner enclosure or production rate in the enclosure. leak rate from the enclosure to the outer space and volumetric flow rate of gases to the enclosure detritiation system. rcspecitvelv. and /I/ x lo\\ ( ~,H.WI,T) and p’f( C;,,,,,, ,,(,) mean permeation through the tnctosure watt and glove\. respectiveI\ C‘(,,,,).,,, means the tritium concentration in the rnclosure and any combination. HT. DT or ‘I‘,. i\ to br taken according to the chemical form of tritium handled. A schematic diagram of the multi-harrier containment system is shown in fig. 1. Concentration of tritium gas in the enclosure. and the concentration at inlet to the enclosure c;~,~~.~j~. from the detritiation system. C&D,TjT,,, are related as follows using the decontamination factor at catalyst bed. K, assuming the perfect mixing model in the enclosure:

~~H.D.T)T,~ = qw,,r,,/K,.

(3)

c (H.D)D.!

(4)

=

C,H,D,Il/Kt,~

C H,.I = C,JK,,

.

where C;tl.t),LO.,means

the concentration of Lvater swamped to the gas flow at the inlet of the adsorption bed in the detritiation system to make hure of adsorption of triliated water if necesbarq. I and 1 are u’ater concentration at the outlet of the catalyst bed and the adsorption bed, respectively. and both value\ can he estimated from the breakthrough curves for water adsorption using the following equations.: “‘=/‘(q,[,

,),()’ 7‘).

(5)

where K,. K, and K, are different because of the isotope effect in transfer processes in the oxidation. Concentration of tritiated water in the inlet gas to the enclosure from the detritiation system, C&r3,7I1o,, is shown as follows where no other unit operations than

where M. y. U, 2. t‘. C&o,,,,,, and T mean water concentration in the adsorbent, packed density of bed. superficial gas velocity in the bed. axial length of the

Air -_

Air

I

letritiation

1

system

detritiation

I I I 1 enclosure I ,

enclosure

systen EO Leak HT-HTO --

Stack

errneat i

H20-02 -<<- --HTO

[

Primary

I. Multi-barrier

c;tainfi~‘/“.“‘

Secondar; Tertiary

Fig.

i7j

containment

system

containment containment

detritiation system

3

bed, void fraction of the bed, equilibrium water concentration at the mass transfer interface and the absolute temperature, respectively, and K,,, is the overall mass transfer coefficient in the water adsorption. Details of the way to estimate the breakthrough curves in the water adsorption or desorption taking the hysteresis phenomena and the isotope effects in account are reported by Kotoh et al. [7]. It should be noted that x and y are not zero even before the breakthrough because there exists the limiting value for each driving agents below which the water adsorption does not proceed. The decontamination factor at the oxidation process is related to the overall mass transfer coefficient as

where K,, a and V,,, are overall mass transfer coefficient in the oxidation process, specific surface area of catalyst particles and catalyst bed volume, respectively. It can be seen from above equations that the overall mass transfer coefficient plays an important role in the detritiation performance and that catalysts which give larger I(, vafues at some oprationai conditioons are desired in use. As the overall mas transfer coefficient is usually given by the following equation, each mass transfer coefficient should be evaluated to understand the behaviour of tritium in the oxidation process: l/K,

= l/k,

+ l/flk,

+ l/k,.

initial tritium concentration mixing in the enclosure.

The pilot catalytic oxidation detritiation system is schematically shown in fig. 2 and various experimental conditions are shown in tables 1 and 2. A constant temperature bath or an electric furnace is used to heat the catalyst bed. The catalytic columns are made of Pyrex glass. Concentration change of hydrogen isotopes other than tritium is determined by using gas chromatography, and the tritium level is monitored by an ionization chamber continuously. Water vapour formed by the catalytic reaction is removed from the bulk gas stream by the packed bed of molecular sieves. activated alumina or silica gel before the analysis by gas chromatography. As for the bulk carrier gases. t\r. He. N, or dry air are used in this study.

stack

t water bubbter

=

%.r,.Td’[

e

{ 1 -

exP( KFQ~‘&/Q>

I] .

(12) The concentration change of the tritium in an enclosure is given by the following equation when R(,.,,,, is given by a pulse function as in the case of rupture of the inner enclosure or when the production rate of tritium suddenly becomes zero:

c(H.D.T)T

ionization

chamber

1 - exp( - K,d&,,/Q) =

c,“,.D.~l~

exp (

“E/Q) (13)

as-

3. Ex~rimentaI

01)

where. k,, @k, and k, are mass transfer coefficient due to oxidation reaction on the catalyst surface, mass transfer coefficient due to diffusional transfer of reactant in a catalyst substrate and mass transfer coefficient to transfer reactant from the bulk gas flow to the surface of catalyst particles, respectively. At the steady state operation, C,,,o,r,, is given by the following equation according to eqs. (l), (3) and (lo), as 4 and pf( C(rr,p,r,r) are usually negligibly small compared to other factors:

c(H.D.T)T

is the whereGI.~.T,T suming perfect

Fig. 2. Schematic

diagram

of experimental

apparatus.

4

Table 1 Experimental

4. Results and discussion conditions

(i)

Hydrogen isotopes Carrier gas Hydrogen isotopes concentration Superficial gas velocity Type of catalyst

Amount of catalyst in bed Diameter of catalyst bed Temperature of catalyst bed

Hz and D1 Ar, He or NL 100-20000 ppm 3-150 cm/s Pt-alumina. Pt-Ag. Pt-C‘. Pd-alumina, Pd-asbestos. Pt-hydrophobic substrate 0.5%30 g lo,16 and 19 cm 0&45O”C

4.1. Chewncul reuction

Applying the Wilson plot method [9] for the Arrhenius plot of the overall mass transfer coefficient in rather low temperature range around the ambient temperature, the following equations are obtained for the reaction using the Pt-alumina catalyst when oxygen concentration in the bulk gas stream is more than three times of the hydrogen concentration: k

Table 2 Experimental

r.H, = 8.82 x 10“ exp( - 10700/RT)

k KHZ .x r.r), conditions

: k,.m = 1 : l/2:

[m/h].

(14)

l/4,

(151

(ii)

Hydrogen isotopes Carrier gas Hydrogen isotope concentration Tritium level Superficial gas velocity Type of catalyst Amount of catalyst Diameter of catalyst bed Temperature of catalyst bed

Hz. D, and HT Ar or N, IO-2000 ppm 0.5-50 mCi/m’ IO-30 cm/s Pt-alumina. Pt-hydrophobic substrate 0.2-0.7 g 0.7 cm 0~200”c

The catalyst pellets are heated at 300°C for 2 h in dry gas stream containing a little hydrogen and/or oxygen by the reason stated elsewhere by the present authors [8]. Details of noble metal catalysts used in this study are shown in table 3.

Table 3 Details of catalysts

rute

Almost the same equations are obtained for the Pd--alumina catalysts. The isotope effect shown above agrees well with the following relationship proposed by the authors [6]: (k,),,/(k,),=

116)

{(krMkr)oJ-‘.

and (kr)7 are the chemical reacwhere (kr)“. (k,)o tion rates when protium, deuterium and tritium are limiting reactants, respectively. in this study, as shown in eqs. (14) k r,HT obtained and (15), is about one order larger than the values estimated using the correlative equation by Sherwood [lo] based on the data by Bixel and Kershner [ll]. This difference comes from the effect of the water amount in the catalyst as explained in the paper by Nishikawa et al. [8]. With the same procedure, k, for the Pt-catalyst with hydrophobic substrate is also obtained as follows: k

r.H,

k r.~:

=

1.46

x IO’” exp( - 25100jRT)

: k,.r,: : kr.,, = 1 : l/2.9

[m/h],

t 17)

: l/X.3.

(18)

used in this experiment

Catalyst

Content

Form

Pt-alumina Pd-alumina Pt-carbon Pt coated Ag Pd&asbestos PI-hydrophobic substrate

0.5% Pt 0.5-l o/r Pd 20% Pt 5% Pt

Pellet Pellet Granular Granular

3Om50% Pd

Fibrous

1% Pt 1% Pt

Pellet Sphere

Particle diameter

BET wrface area by Nz (m2/g)

(mm) l-3 3 1.2 1.2

1. 2 3

--80-110 150-240 140 0.3 17

M. Nishrkawa

The isotope effect shown in the above equation again agrees well with the relationship obtained from eq. (16). Comparison of eqs. (14) and (15) with (17) and (18) indicates that the catalyst with alumina substrate gives a larger oxidation rate for tritium, though the catalyst with hydrophobic substrate gives a larger oxidation rate for H,. 4.2. Diffusion rate in catalyst substrate K, 1/K,

at the elevated = l//3k,

temperature

is represented

as

+ I/k,.

[m/h]

for H,.

shows much smaller values as

&s,wz = 15.2fi

[m/h],

/3ks,Hz: /3k,.DI: /3k,,,,=

(22) 1 : l/3.1

flk a,~, : t%,D, : i%,w, : Ws,T, = 1 : l/1.38

: l/1.66.

(23)

The reason why so small values are observed for the hydrophobic substrate is not clear. However, it may have close relation to the pore size distribution of the substrate, as the decrease of K, with time is also observed at the oxidation process using molecular sieve (MS 4A) or hydrophobic substrate with fine micro pores as the substrate of the noble metal catalyst. 4.3. Gas phase mass transjer rate at inferjace For estimation of k,, correlative equations by Carberry [13] or Chu et al. [14] are often used. The present authors, however, recommended the following equation for the cases when the particle diameter in the packed bed is smaller than 3 mm: ( k,/u)&c2/3

= t.l5(R~/~)-“*(J~/~~~~~,

(24)

where d, and d,, are particle diameter and the standard particle diameter (= 3 mm), respectively, and the Schmidt number, SC, and the particle Reynolds number, Re,, are shown by the following equations:

(21)

The values of bk, are so large that they give effect on K, only at the elevated temperature and the large superficial gas velocity. /3k, obtained for the hydrophobic substrate in this

SC = PlU&, Rer = (d~~p/~~/(l-

(25) ~1,

0 observed R’%

(261

where p, p and DG are specific weight of the bulk gas, viscosity of the bulk gas and diffusional coefficient of hydrogen isotopes in the bulk gas, respectively. The isotope effect in k, can be estimated as follows from eqs. (24) and (25) in the argon atmosphere: k &HZ: k8.n21kg.,, 1kg.D, = 1 : l/l

---------I-------

: l/8.5.

(20)

From the correlative equation by Fujita for the diffusional coefficient of gas phase (121, the isotope effect on /?k, in the argon atmosphere is expected as follows:

: l/1,38

study, however,

(1%

because l/k, can be neglected. As /3k, is independent of the superficial gas velocity (though j3k, is independent of the superficial gas velocity (though k, is dependent as shown later), @k, is obtained as follows from fig. 3 for the Pt-alumina catalyst: /3k, = ll8@

5

et al. / Oxrdurmn of tritrunr

.24 : l/l

.24 : l/l

.40. (27)

KF

Comparison of k, with k, and k, shows that k, becomes the rate controlling step at the higher temperature than about 100°C for the noble metal catalysts with alumina substrate.

----

4.4. Overall mass transfer coefficient Pt-Alumina

Cot.

mlh

Fig. 3. Effect of superficial gas velocity on oxidation rate.

The estimated values for the overall mas transfer coefficients using eqs. (14), (15), (20), (21). (24) and (27) are compared with the observed values in figs. 4 and 5 for the Pt-alumina catalysts. As can be seen from these figures, solid lines representing the estimated values agree well with the observed values. These figures also indicate that Pt-alumina catalysts are available at the

_

t

r*

100

Pt-hydrophobic

dp-lmm

Pt-Alumina

uq2Ucmls

for H2D2 in Ar

‘8 261 /’

8’

estimated

observed o

H2 in Ar D2 in Ar

10 _ l

HT in N2

52 2.8

103 j

a( 261

32

34

observed

HT or) N2

value

HI

in

/

0

D2

in Ar

Ar

i

*

Hi in N2

I

l/K

plot of overall oxidation

value

0

/

3.0

rate for Pt-alumina

I 28

I 3.0

3.2

t

OC 100

I

80

I

I

Pt-A~urn~na t-l2 or 02

60

I

40

20

0

I

I

plot of overall suhstrate.

oxidation

rate for Pt cataivst

dp-3mm

in Ar

10: 3 .c ;‘

~ 10;

VOhX

observed

Fig. 6. Arrhrnius with hydrophobic

34 K-1

1000/T

150

G!-

A

5.9

\

A

10

I

I

I

2.4

2.6

28

I

I

3.2

$4

I

3.0

1000/T

Fig. 5. Arrhenius catalyst.

for H2.D2 tn Ar

$estimated

1 il

2.2

./

value

‘Ot

1000/1

r

substrote

value

o

Fig. 4. Arrhenius catalyst.

.

- .__&__

dp=Z?mm

ug=212em1s

HT in N2

O(

40

plot of overall oxidation

I

3.6

K-’

rate for Pt-alumina

ambient temperature without heating as reported b> Sherwood et al. [15]. though 300-400°C is required to get the reasonable oxidation rates of tritium when copper oxide or hopcalites is used as shown previousI> hv the present athors [5,6]. The estimated K, values for the Pt catalyst uith the hydrophobic substrate also agree well with the observed values as shown in fig. 6. K,- for the Pt-alumina catalyst under various condrtions are estimated in fig. 7. As is shown in this figure. k, is the rate controlling step at temperatures beloa several tens of degree of centigrade and X, nbovc 100°C. Accordingly, it is reasonable to heat the bed filled with the Pt-alumina catalyst to get a larger decontamination factor in the oxidation process when the bed temperature is below several tens of degree of centigrade. An increase of the superficial gas velocity or increase of the catalyst bed volume other than heating can be the resonable action to take when the bed temperature 1s already ahove 100°C. The pumping capacitk through the enclosure detritiation system, however. should have

Kozeny-Karman equation (161. It should also be noted that the isotope effect observed on the overall mass transfer coefficient varies with change of relative rates of k,, &k, and k,, as the isotope effect in each mass transfer coefficient is different. It is observed in this study that the activation energy or the isotope effect in k, keeps the same value for certain combinations of catalyst and substrate, though about 20-30s variation in the Frequency factor is observed when the catalysts from different factories or lots are compared. Accordingly, it is safer to check the frequency factor of k, for each catalyst with protium before packing into the catalyst bed of a detritiation system. Then, k, and consequently k, for other hydrogen isotopes can be obtained using eq. (18) and other equations stated above in this paper. When k,‘s for protium and deuterium are known, more close k, for tritium can be obtained by using eq. (15) than the value estimated using the method stated above. Though K, for fresh Pd-asbestos gives desirable values, it decreases rather rapidly with time. Pd-asbestos catalyst is not to be trusted for the long term use because of loose binding of Pd particles to the asbestos fibre and easily changeable density of asbestos flock. Pt-carbon catalyst gives the same performance as Pt-- or Pd-alumina catalyst. However. it cannot be used at elevated temperature because of occurrence of oxidation of the carbon substrate itself. Pt--silver catalyst with the composition shown in table 3 cannot be used for the oxidation of tritium because of the small reaction rate. This observation agrees with the tendency stated by Allison and Bond [17] as that 70 to 100% silver alloys with palladium was inactive at 100°C for hydrogen oxidation. High oxida-

ug = 64&m/s ,# 160cmis

“\.

k’t-Alumina cat dp= 3mm

\ \ 1’ \

Hydrogen isotope in Ar H2 D 2 7

____--__ ---T

I

I

20

2.2

I

I

2.6 24 1000/T

-l,

I

I

I

2.8

3.0

3.2

I 3.4

1

3.6

l/K

Fig. 7. Estimated overall oxidation rate.

some surplus when the superficial gas velocity or the catalyst bed volume is changed, because the pressure drop of gas stream through the packed bed is increased with increasing both parameters as shown by the

3mm R-Alumina cat.

OO

200 1

400 I Time

Fig. 8. Water adsorption

breakthrough

600 I

800 1 h

curve for Pt-alumina catalyst bed.

lOO0

x tion capacity, however, is expected for the palladiumsilver permeation membrane at the large palladium composition and at the higher temperature than several hundreds degree centigrade. Use of a small amount of Pt-silver catalyst in the upper course of the catalyst bed with the noble metal catalyst may be useful to scavenge sulfur compounds which are poison to the noble metal catalysts. 4.5. Water adsorption performance

of catalyst partlc1e.v

The tritium oxidized by the catalyst bed is expected to be adsorbed on the adsorbent placed at the downstream of the catalyst bed in succession. As the catalyst particles, however, usually have the fair capacity to adsorb water, it is necessary to evaluate the water adsorption breakthrough curve for the catalyst bed itself. Nishikawa et al. [18] observed that Ptor Pd-alumina catalyst adsorbed about one-third of water that could be adsorbed on activated alumina. Fig. 8 shows some examples of the water adsorption breakthrough curves by using eqs. (7)-(9) for several inlet water concentrations where the vapour pressure at the outlet of the bed before breakthrough is assumed to be 0.06 Pa based on the observation by Kotoh et al. [7]. Fig. 9 shows the amount of water trapped in the catalyst bed evaluated from the breakthrough curves. These figures show that a fair amount of tritiated water may be retained not only in the adsorption bed but also in the catalyst bed. Accordingly, dehydration operation should be also given to the catalyst bed to recover all tritium from the detritiation system, though no dehydration installations are given to the catalyst bed of the

emergency tritium cleanup system of the Trmum Syatern Test Assembly in Los Alamos 1191. It IS possible I&) avoid the water adsorption in the catalyst bed by using the noble metal catalysts with the hydrophobic SLIIF strate or by using the metal oxide. The overall mass transfer coefficients in the oxidation of tritium, ho\\.. ever. are rather too low to use in the moderate temperature range with these catalysts at the present state. The amount of tritium in the Pttalumina catalyst bed and the adsorption bed with molecular sieve (MS 5A) composing an enclosure detritiation system of thk: secondary containment is shown against time in fig. ICI. and various conditions assumed in estimation using eqs. (1).-(12) are listed in table 4. The breakthrough time ot tritiated water obtained hy using eys. (7)~-(9) 1s ,11so compared in table 5 for the catalyst bed and the adsorption bed. It can be seen from fig. 10 that a large portion of tritium is trapped in the catalyst bed especiallv before the breakthrough for the catalyst bed has CX’curred where utility frequency of gloves means a\ fo!lows: utility frequency

(2X)

It can also be expected that a catalyst bed of 10 kg and a MS 5A bed of several tens kg are enough for continuous operation of an enclosure detritiation system in the secondary containment for one year where the conditions are as those listed in table 4. The amount of tritium in the secondary enclosure estimated under these conditions by using eqs. (l)-(9) is shown in fig. 11 for the cases before the breakthrough of tritiated water for

I

Q =h0m3/h

0.10 -

I

Vcot=0.01m3 Db=O.l6m Pt-Alumina

1=25OC

humidity 90 %

cat. dp=3mm 70%

min

Tlmc Fig. 9. Amount

of water trapped

in the catalyst

bed

numher of gloves in use of gloves = __ total number of gloves

M. Nishikaw

er al. / Oxidation

of tritium

Y

x1(12 6

-----

trttium

caught

in cat bed

I,

MS bed

II

/ tritium released,’

G

4 utility frequency of gloves

._ ,s .-

2

0 time

day

Fig. 10. Tritium amount in catalyst and adsorption beds.

the adsorption bed has occurred. The tritium level in the secondary enclosure is kept at about 15 mCi/m3 without isotope swamping because the water permeated through gloves into the secondary enclosure from the tertiary

Table 4 Conditions for simulation enclosure * Prrmuly

of tritium

behaviour

in secondary

(0.9~10-~

atm-cc/s)

enclosure

Tritium amount handled Leak rate to secondary enclosure Secondarv enclosure System volume Gas circulation rate Glove (buthyl rubber) Glove surface area Glove thickness System gas Amount of Pt-alumina catalyst Amount of MS 5A Room (tertiary enclosure) temperature Room humidity

10h Ci IO-s/day

10 m’ 5h-’ 50 pairs 1 m*/pair 0.8 mm Argon 10 kg 20 kg 2o”c 60%

* As for threshold value at water adsorption 1 ppm for catalyst and 0.5 ppm for molecular sieve (MS 5A) is used.

enclosure acts as the swamped water, where permeation rates through gloves are estimated using values by Wittenberg et al. (201. The tritium level in the secondary enclosure increases at smaller utility frequency of gloves as shown in fig. 11 because of too low water concentration in the bulk gas stream to give effective water adsorption in the catalyst bed and the adsorption bed. The amount of tritium permeated to the tertiary atmosphere through gloves is about several hundreds of micro curies per day as shown in fig. 12 and nearly all is in the form of tritiated water.

Table 5 Breakthrough time (in days) at tritiated water catalyst bed and molecular sieve (MS 5A) bed Utility frequency of gloves (W)

Catalyst

100 50 25 10 5

6.4 12.1 25.6 155 *

* Inlet water concentration water adsorption.

bed

adsorption

for

MS 5A bed

199 287 515 1081 1926 is below

the threshold

value

at

r

tritlum

\

Secondary

enclosure

\

\

in the ambient

4dwrption grab&

\

amount

total

\

hecause

retained

in

--__

----___

;I

the

breakthrough

‘1..

temperature

performance fair

amount

catalyst

for

range.

of the catalyst i>f

bed

the catalyst

bed

tritiated

must w,iti‘r’

c\pecially

hel‘orc

hc ii the

bed.

_

HT form References

Ill

t

\“.--“‘“.” I

I

121M.

Nlshlkawa.

and M. Ohta. J. Nucl. SKI 1 ccl+

Y. Yamamoro

Energy Sot. Japan 25

utlllty frequency of gloves Fig. 11. Tritrium

H. NakaJima

nol. 10 (19X2) 186.

I 75

50

25

S. Kurokl.

A 100

%

level in atmosphere of secondary enclosure.

131 M.S.

Ortman.

E.M.

and S. M;ltsunng;~. J. :\iom~c

(1983)734

Larsen dnd Ahdel-Kh,illk.

nol.,~Fuu~>n 1 (1981)

ERDA-50. [41 C‘.J. Kerhwcr, burg. Ohio (June 1975).

Mound

I_‘thorat,w\.

151 M. Nlshikawa, T. Iuyam;r Technol. 70 (1983) 145.

and K. Shlnnal.

[61 M. Nuhikawa. K. Shlnnal. S. Ma~wnaga J. Atomic Sot. Japan 26 (lYX4) 70X

ic

~.

$

Tech

X~I,I~~I\-

.l. Nucl

\CI

;~nd 1. Kln~~\hlr,l.

111prrparatlkw. I71 K. Kotoh, M. Enoeda and M. Nl\hlkau:r. partly reported by M Enoedn II) hl. Fng. t&l\. K\tlxhu

400

4 ol SI

Nucl.

255.

)-

total ___-

_____---HTO

I “I\

amount

(1984).

[Xl M. Nlshlkawa. K. HigashlJima. and ~1.. lakeiahi, in preparstwn.

form

Meeting of AESJ, Tokyo.

191E.E I lOI 4.E.

37 (lY15)

Sherwood. CONF-761 Tech.. American

M

lznoed,~

partly reported in .Annu,tl

1983. and Osaka.

Wilson, Trans. ASME

Fwtem\

K. Munakata.

I.

101-t Nuclear

19X4.

47.

74th C’onf. on Rcmotc‘ Sot.. Wa\hln_econ. I)(‘.

1976

IllI

I.(‘. Bixel and C.J. Kerahnrr.

LlSAI:C Report uwy Fig. 12. Tritrium

LIZI I.

frequency of gloves

[Ii]

permeated to tertiary enclosure

through

gloves.

Wash-1332

FuJita, Kagaku-kikal

J.J. (‘arherry,

AlChE

mc,re Laboratory, Ilhl [I71 Catalytic

Ptstudy

oxidation

of the noble or

metal

Pd-alumina because

P.C (1077)

5. Conclusion

bed

they

rates catalysts catalysts give

of

tritium

in

the

are obtained is recommended

effective

oxidation

use of in

rates

E.<;.

C’drmsn.

B.G.

Wetteroth.

Monahan.

Griffith.

(‘hem.

R.A

Inatn.

I:ng. Progr.

McWilliam\.

UCRL.-52X1

Livermorc.

Trans.

234.

1. Laarencc

t S. 1 !\cr

(‘al. (July lY79). (‘hem.

Fngr\.

(L~lndon)

2:

1%).

.Alhson and G.C.

Bond. (.‘atalyus

Rev. 7 (lY72)

233.

pdr-tl! 11x1 M. Nlshikawn and M. Enoeda, tn preparation. reported in Annual Meeting of AE,SJ. Tokyo. 19X3

catalyst

and

15 (1951)

J. 6 (1960) 460.

I141 1.c‘. Chu. J. Kalil and W.A. 49 (105.3) 13.5. Sherwood. 1151 4.b Ilrlhe and <‘.M.

Proc. 2nd l:n\~r. I’r~~i c <)nt (1974).

this of

1191 R.V. Carlson. US-Japan Workshop on Tritium Handling. Lo\ ,Alamoa National Laboratory. Lo Alamo\. NM. 19X3. [XI]

L.J. Wlttcnherg.

CONF-760935

(1976).