DECAY HEAT CALCULATION - Nuclear Energy Agency (NEA)

NEACRP-319 "L"

NEANDC-275 "-0"

DECAY HEAT CALCULATION An International Nuclear Code Comparison

B. DUCHEMIN Laboratoire de Metrologie des Rayonnements Ionisants

C.E.N., Saclay, France

C. NORDBORG NEA Data Bank,

Gif-sur-Yvette, France

1.008 1.006- 1.004- 1.002- l.OOO- 0.998- 0.996- 0.994

0 1 2 3 4 5 6 7 8 9 10 11 12 13

COOLING TIME (lO**N Seconds)

NEACXP- 319 “L” NEANDC!- 275 “U”

0 e

DECAY HEAT CALCULATION

An International Nuclear Code Comparison

B. DUCHEMIN

I.,abcwal.oire de Metrologie des Rayonnements Ionisants C.E.N., Saclay, France

C. NORDBORG

NEA Data Bank, Gif-sur-Yvette, France

‘1’1~ renult.s of an international code comparison on decay heat are presented and dis- crossed. Participants from more than ten laboratories calculated, using the same input dabn, decay heal: for thirteen cooling times between 1 and 1013 sec. Two irradiation cases were lm~psed: fission pulse and 3x10’ seconds of irradiation of 235U fuel. The resuhs are analysed and compared. This inter-comparison shows that, if the same input data are given, most of t,he codes give very similar results for the decay heat and consequently also for the fssion product contribution.

Contents

1 Introduction

z Contributions Received

3 General Comments

4 Comments on Benchmark no. 1

5 Comments on Benchmark no. 2

0 Conclusion

7 List of Figures

8 List of Tables

3

4

7

10

11

12

13

14

*

a

.This report.contnins the preliminarp’results df an international effort to compa?e the results obtained by codes which calculate decay heat either for pulse fission or after irradiation. These decay heat calculations are very important for reactor studies. The comparison was init.iat.ed during the specialist meeting on data for decay heat predictions held at Studsvik (Swetla~) in September 1987. The objective is to verify that the discrepancies appearing Mwcen different calculations are due to the data used (yields, capture cross-sections, nuclide m3m energies, ) and not to the method used to solve the generalised Bateman equat.ions which describe the nuclide evdlution during irradiation and cooling.

The specification of the exercise is given in the annex 1. The participants were asked to calculate the decay heat, with uncertainties :if possible, for.two cases, each for several cooling t,imes, using a given set of input data. The results should contain, for each cooling t.ime, information on the total decay heat, the p and 7 parts separately and, a list of the nuclides which contribute more than 1 % to the total decay heat. The two cases agreed U,‘O” were:

1. R 23511 fission pulse,

2. a 3x IO’ seconds irradiation of 235U with no burn-up.

Tbr cooling times chosen ranged from 1 second to 1Ol3 seconds. The input data contained inl’orm;rtiw on: yields, spectroscopic data, and capture cross-sections. Only the decay heat dw 1.1, fission products should be calculated. The decay ,heat due to actinide forma- t.ion was omitted from this comparison.

This report is organised in the following way. S&on 2 ,&es a’stirvey of the co&b&ions received and are grouped in two classes: class A for analyti&l solution of the Bateman equations, t,he class B for numerical solution of these same equatioix. Section 3 gives some general comments and sections 4 and 5 contains comments on the results from benchmark no. 1 and benchmark no. 2 respectively. Section 6 contains a brief conclusion.

3

2 CONTRIBUTIONS RECEIVED

The contributions received can he divided int.o two classes: one for analytical s&&xx of the equations and one for numerical solutions.

Class A: Analytical solutions

Code name: Participants: Address:

AFPA RUZHANSKY P.A., RUBTSOV P.M. Moscow Engineering Physics Institute, Kashirskoe Shosse 31, 115409 MOSCOW M-409, USSR


CINDER-10 BEARD C.A., ENGLAND T. Los Alamos National Laboratory, Group T-2, Mail Stop B243, LOS ALAMOS, NM 87545, USA

Code name: Participant: Address:

CINDER WANG DA0 Chinese Nuclear Data Center, Institute of Atomic Energy, P.O. Box 275(41), Beijing, P.R. China a


DCHAIN TASAKA K., IHARA H, Japan Atomic Energy Research Institute, Tokai-Mum, Naka-gun, Iharaki-ken 319.11, Japan

Code name: Participant: Address:

FISPG TOBIAS A. National Power Nuclear, Berkeley Nuclear Laboratories, Berkeley, Gloucestershire GL13 9PB, U.K.

4

C!Odl? IlilnlF: INVENT

Parl.icipiwl~: Address:

H.UDSTAti G. University of UppSala, ” The Studsvik Neutron Research Laboratory, S-611 82 Nykijping, Sweden

Code name: Participants: AddEW

PEPIN NIMAL B., DIOP C. C.E.N. Saclay, DEMT/SERMA/LEPP F-91191 Gif-sur-Yvette CEDEX, France

Class B: Nun~erical solutions

C!ode name: Part.icipanbs: Address:

FISPIN JAMES M.F. AEE Winfrith, Nuclear Data Group, Reactor Physics Division, Dorchester, GB-Dorset DT2 8DH, U.K.

Code name: Parl.icipant.:

Address:

KORIGEN WIESE H.W. Kernforschungszentr~~~ll Karlsruhe, Instil.ut fiir Neutronenphysik, Postfach 3640, 75 Karlsruhe, Rep. Fed. of Germany

Cbde name: Participant: Address:

MECCYCO GILLET, G. C!EA/CEN Cadarache, DRP/SPRC, F-13108 Saint Paul lez Durance Cedex, France

5

Code name: ORIGEN-S

Participants: BRADY M.C., BOHNHOFF W.I., HERMANN 0.W

Address: Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 378314238 USA

3 GENERAL COMMENTS

Some of the comments below cqncerning the input data :were given by the participants:

A. InconsisteIic~“het.ureen Ld$&d&t &d cu&&ti~e yields:

0

0 0

This inconsistency arose for some nuclides hut its influence on the results is’less than 2 per-mil at 1 sec. cooling time and 1 per-mil after.

.;,: The fact that branching ratio may not sum to 100 is gnly due to round-up differ- WXS. It has no r&l itl?portanck pn the r&&t+

C!. Cnpt.ure branching ratio

The capture cross-section branching ratio when the daughter has ground and iso- merit state was not given. This has however no influence on theresults (5 1 per-mil) as shown by the..PEPIN cr%tribution, where &ults had been obtained for the two hypot.hesis: 100 percent on ground-state, and 50 percent on ground state and 50 percent on isomeric state.

1). Uncertainties.

Only I.he INVENT and KORIGEN results were given with uncert&inti& In the case of KORIGEN it. WXR stated, that the uncertainties resulted from energy release only. The INVENT code used all uncertainties in the input data in the calculations. This code gives for example uncertainties for the total decay heat for.benchmark no 1 t.hat varies from about 5 percent at very short and very long cooling times down 1.0 about, 1.3 percent at medium cooling times. The corresponding values given for benchmark no 2,by INVENT tie:, about 1 percent’ at short cooling times up &about 10 percent at very long cooling times. It should be. noted ,that these quoted uncertainties are relevant to t.his exercise only

..:a~ and not to a real c&se of dectiy.heat calculation, as the input data did not correspond to a realistic case and did not included a complete set of uncertainties.

E. Computing times.

‘I%<? object.ive of thisexercise was not to compare computing times otl different con1- lm1.w~. Nevertheless; for-information, Table 1 summaiises the values-given by each cml.ril~utor.

Followillg 1.11~ NEANDCINEACRP Task Force meeting on Decay Heat Predictions held al 1.11~: NlM Data Bank on 21st and 22nd September 1989, when preliminary results were presented, some contributions were revised with subsequent corrections to the codes:

a. Double precision

In the case of INVENT and KORIGEN some calculational parameters were modified to double precision in order to better reproduce the results at long cooling t.imes.

h. Wrongly lab&d data.

Two set of results, one with the benchmark data and one with the local data library, were given for the AFPA code. The hen&mark data results did not agree very well with the results of other contributions, but it was noted t,hat the result,s were wrongly labeled, and it was really the results for the local data library that were deviant. This deviation was explained by different treatment of conversion electrons and X-ray data in t,he two set of results and a re-calculat.ion showed much better agreement between the results.

c. Capture effects in benchmark no. 2.

The first CINDER results did not take into account the capture effects, but. t:his was corrected in a second set of results.

d. Wrong input data

The first results from hen&mark no 2 from the code KORIGEN were discrepant. and the reasons were two: misunderstanding of the interpretation of the one group capture cross section and a typing error resulting in an irradiation of 1 x 10’ i:lst.ead of 3 x 10’ seconds.

e. Burn-up effect.

(I, In the specification of benchmark no. 2 it was stated that no burn-up sho~dd I:ake place, which is unrealistic, but avoids further complications in a inter-conli)aricol, 0 benchmark like this. One code, INVENT, which had a built-in hum-up calcnlat.ion routine had to be modified to keep the amount of Uranium constant during the long irradiation.

f. Delayed neutron effects

Following the discussions of the first benchmark results, the FISPG code was revised to avoid any manual manipulation of the fission yields (to account for delayed net,- tron effects). This involved extension of the linearised decay chains I:O account. for the delayed neutron effects as well as sane minor data manipulation amendment.s t,o the FISPG code itself.

8

g. Subdivision of then i+radkti’on tiine. .’ ’ ’

In benchmark no 2 a subdivision of the irradiation time was not. prescribed in t,he specifications. Theoretically in case of constant coefficients the solution does not de- pend on this subdivision. Numerically, however, a certain dependence is introduced by treating the chain equations with respect to the half-lives of the nuclides in the chains, as in.t,he code KORIGEN. High total decay heat values were no&d before for KORIGEN at lo7 and 10’ seconds cooling time but this dependence was since st,rongly reduced. The values are still slightly higher that the average but well wit,hin t:hc quoted uncertainties. The same tendency was also found in the results of the OIUGEN-S code.

L~ollowing these ikrations, the results from the different codes agree very well and only minor differknces are found. No systematic differences between the results of the Analytical and Numerical codes could be found.

e e

9

4 COMMENTS ON BENCHMARK NO. 1

The objective of the pulse fission calculation was to test the ability of the codes to use the fission yields and to treat correctly the mass decay-chain calculation.

As shown in Figures 1 and 2, all codes give results for the total decay heat which agree, on the average, to better than l/2 percent. This is well within t,he uncertainties given by the INVENT and KORIGEN result. A few points can be noted when studying figure 2:

CINDER-10

Relatively high values were reported for cooling times lo5 and 10’ seconds.

INVENT

The results are about 0.2 percent above the average. This is most probabIy due to t;he fact that the amount of Uranium was fitted to give 1.25 * 1O’5 fissions and the program only outputs the nun~ber of fissions with 4 significant digits, which means an uncert.ainty of 5 * 10” fissions or * 0.04 %.

KORIGEN

The results between lo4 and lOlo seconds cooling time are all above the average, 1x11. within 0.5 % of the average.

ORIGEN-S

The somewhat scattered results for this code is due to the fact that the results were given with only two significant decimals. This effect could for example be seen in Table T where the fission product contribution after lo9 seconds cooling time add up to over 100 percent. Relatively low values were reported for cooling times lo5 and above 10” seconds.

10

0

e 0

5 COMMENTS ON BENCHMARK NO. 2

The objective of long irradiation (3x107’se~ond~) calculation was to test the ability of the codes to treat the capture (or absorption) problem.

As shown in Figures 5 and 6, all codes give results for the total decay heat which agree, on the average, to better than l/2 percent, except maybe for the CINDER contribution by Wang Dao. A few points c& be noted when studying figure 6:

CINDER-10

Relat.ively high values were reported for cooling times 10“ and lo5 seconds.

CINDER

The result:s are on the average,about 1 to 3 percent lower than dther results.

INVENT

The resu1t.s are about 0.2 percent abpve the ayerage, except for cooling times above IO”’ seconds. This is most probably due to the fact that the amount of Uranium was fitted to give 1.25 * lOI fissions and the program only outputs the number of fissions with 4 significant digits, which means an uncertainty of 5 * 10” fissions or f. 0.04 %.

Two relatively high values are noted for lo7 and 10’ seconds cooling time (see item g. above). At cooling times 10” seconds and above the results are about 0.2 percent higher t.11an average.

OFUGEN-S

The somewhat~ scattered results for this code is due to the fact that the resnlts were given wit.h only t,wo significant decimals. This effect could for example be seen in Table 13 where t.he fission product contribution after 10’ seconds cooling time add up to over 100 percent. Two relatively high values were reported at lo7 and 10’ seconds cooling time (see item g. above). Somewhat low values were reported for cooling times above 1O’O seconds as in benchmark no 1.

6 CONCLUSION

In the present exercise t,he following codes were compared:

Analytical Numerical

AFPA CINDER-IO CINDER DCHAIN FISPG INVENT PEPIN

FISPIN KORIGEN MECCYCO ORIGEN-S

The overall results of the calculation of decay heat and contributing fission prot1uct.s are in very good agreement for the codes. The results given by the CINDER code (contribution by Wang Dao) are on the average 1 to 3 percent lower that other results.

The objective of this exercise was to ensure that t.he discrepant. results for decay heat. calculation obtained in different laboratories were due to different input data and not I& different: solutions of the equations describing the fission product evolution. This objective has been reached.

This inter-comparison has permit.ted the participants to gain confidence in their codes and minor modifications to a few of the codes have been noted as a result of this exercise.

12

*

List of Figures

Large scale plot showing the rebults.at diffe&nt &ling t&s for the total decay heat of lmichmirk tie’ 1 (235U fission pulse irradiation) Fine scale plot showing the results at different cooling times for the total decay heat of henchn%rk no 1 (‘s% fission pul~e’irradiatjon) ~. Fine scale plot showing the r&As at different cooling times for the p decay heat of benchmark no’ 1 (sssU fission pulse irradiation) Fine scale plot showing the restilts at different cooling times for the y decay heat of benchmark nb i ( 235U fission’pulse~irradiation) Large scale plot showing the results at different cooling times for the total decay heat df he&hmark’xio 2 (I&g irradiation) :, ~. ‘. Fine scale plot showing the results at differ&t coqling~&mes for the total decay heat of henchniark no’2 (Long irradiation) Fine scale plot showing the results at differ+nt cooling times for t.he 0 decay heat of h&chmark’no 2 (Iqg i+ra+tion) ~. 1 ~. .’ Fine scale plot showing thcresults at different cooling times for the 7 decay he&t of benchmark no 2 (Long irradiation) . ~1 .

“,

15

16

17

18

19

20

21

22

13

List of Tables

1 2

3

4

5

6

7

8

9

10

11

12

13

Computers and CPU time (seconds) used in the exercise 23 p Decay Heat results (in MeV/sec) for a ‘W fission pulse given at cooling times from 1 second to lOI seconds 24 7 Decay Heat results (in MeV/sec) for a 235U fission pulse given at cooling times from 1 second to 1Ol3 seconds 25 Total Decay Heat results (in MeV/sec) for a 235U fission pulse given at. cooling times from 1 second to lOI seconds 26 Fission product contribution (in %) to the total decay heat for a ZRSll fission pulse after 10 second cooling time 27 Fission product contribution (in %) to the total decay heat for a 235U fission pulse after 10’ seconds cooling time 28 Fission product contribution (in %) to the total decay heat for a 235U l&ion pulse after 10” seconds cooling time 28 /? Decay Heat results (in MeV/sec) for a 3~10~ seconds irradiation given at. cooling t,imes from 1 second to 1Ol3 seconds 21) y Decay Heat results (in MeV/sec) for a 3~10~ seconds irradiat.ion given at. cooling times from 1 second to 1Ol3 seconds 30 Total Decay Heat results (in MeV/sec) for a 3x lo7 seconds irradiation given at cooling times from 1 second to 1Ol3 seconds 31 Fission product contribution (in %) to the total decay heat for a 3x10’ seconds irradiation after 1 second cooling time 32 Fission product contribution (in %) to the total decay heat for a 3x10’ seconds irradiation after IO4 seconds cooling time 33 Fission product contribution (in %) to the total decay heat for a 3x10’ seconds irradiation after 10’ seconds cooling time 34

0 l

14

$ d ld ld ld ld 10’ ld lo” 10’ lo” lo’ ld” ld’ 16’ ld”

Cooling Time (see)

INTERCOMPARISON OF CODES FOR DECAY HEAT CALC. TOTAL DECAY HEAT FOR A FISSION PULSE

0 CIr.“u--l” (ClmLAIVUI

A DCHAIN (TA%KA) + FISPG (TOBIAS) x FlSPIN (JAMES) - _- o IN’

z d I 4 I,,,,,, I I ,,,,,,, ,/ ,,,,, /,,, I,/ , , ,,,,(,, I ,,,,,,, / /,/ ,,,, , ,,,,,,, , ,,,, */, ,,,,,,, / I /,I, 10” ld ld ld 10‘ ld 10” lo’ 10” 10’ Id” lo” ld’ ld’

Cooling Time (set)

INTERCOMPARISON OF CODES FOR DECAY HEAT CALC

ld lo” lo’ 10” ld ld” ld’ ld’ ld’ Cooling Time (set)

INTERCOMPARISON OFCODES FOR DECAY HEAT CALC ~ y DECAY 0

HEAT FOR A FISSION PULSE I I I I I I I I I

0 0 A + X 0 V e @ E

AVERAGEOFALL AFPA (RUBTSOV) cmm-10 (ENGLAND) DCHAIN (TASAKA)

I I I I I I I 1 I

ld 10" 10' IO" 10' Cooling Time(sec)

10” ld ld ld 10' 10' to" lo' IO" 10" ld" Id' ld' ld" CooIingTime(sec)

INTERCOMPARISON OFCODESFOR DECAY HEAT CALC. TOTALDECAY HEATFORA LONG IRRADIATION

10” ld ld ld 10' lo' 10” lo’ lo” ld lo'" lo" ld' ld' CoolingTime(sec)

l * l

INTERCOMPARISONOFCODESFOR DECAY HEATCALC

ld 10" 10' lo" lo" Id" Id' ld' Id" Cooling Time (set)

HEAT CALC INTERCOMPARISON OF CODESFORDECAY 1. 7 DECAY HEAT FORALONGIRRADIATION 2

----- AVERA Gl$ OFALL(EXCEFTCINDER)

Bs PEPIN (NIMAL)

lo' 10' ld 10' ld 10" lo' 10" 10' lo'" Cooling nme(sec)

aa 0

Table 1: Computers and CPU time (seconds) used in the exercise

Code

AFI’A C!lNDER-IO CINDER ~DCMAIN .FISPG FISPIN 1N VENT KOH.IGEN ME(~!C!YC!O ORIGEN-S PIWIN

Laboratory-

Moscow Los Alanios Pekin Tokai-mura Berkeley Winfrith Studsvik Karlsruhe Cadarache Oak Ridge Saclay

Computer model

ES-1060 CRAY-XMP CYBER-1701825 FACO&l M-780 @M-4381/23 SUN 3/60 VAX-8200 SIEMENS-7890 IBM-9377 IBM-370/3033 IBM-9371

Benchmark no 1

100 17.98

0.69 3.5

N.C!. 95

1.75 -90

20.34~ N.C.

I 1

3enchmark no 2

131 17.91 59.75 0.85 4.22 N.C.

95 2~33~ -90

24.43 N.C.

23

Table 2: p Decay Heat remits (in MeV/sec) for a 235U fission pulse given at cooling t.inlen from 1 second to 10’3 seconds

Computer code

AFPA CINDER-IO DCHAIN FISPG FISPIN INVENT KORIGEN MECCYCO ORIGEN-S PEPIN

Colllput.er code

AFPA CINDER-10 DCHAIN FISPG FISPIN INVENT KORIGEN MECCYCO ORIGEN-S PEPIN

chlllputer code


100

3.358 E-02 3.366 E-02 3.359 E-02 3.359 E-02 3.359 E-02 3.359 E-02 3.359 E-02 3.359 E-02 3.36 E-02

3.359 E-02

104

8.224 E-06 8.200 E-06 8.198 E-06 8.197 E-06 8.198 E-06 8.216 E-06 8.227 E-06 8.197 E-06

8.3 E-06 8.198 E-06

10”

5.351 E-12 5.351 E-12 5.351 E-12 5.347 E-12 5.351 E-12 5.361 E-12 5.362 E-12 5.351 E-12

5.3 E-12 5.351 E-12

I I I I

10’

1.073 E-02 1.073 E-02 1.073 E-02 1.073 E-02 1.073 E-02 1.074 E-02 1.073 E-02 1.072 E-02 1.07 E-02

l.Oi3 E-02

105

3.282 E-07 3.349 E-07 3.282 E-07 3.281 E-07 3.282 E-07 3.289 E-07 3.290 E-07 3.282 E-07 3.24 E-07

3.282 E-07

10'0

7.393 E-15 7.393 E-15 7.393 E-15 7.390 E-15 7.393 E-15 7.416 E-15 7.440 E-15 7.393 E-15

7.3 E-15 7.393 E-15

102

1.958 E-03 1.958 E-03 1.958 E-03 1.958 E-03 1.958 E-03 1.962 E-03 1.959 E-03 1.957 E-03 1.96 E-03

1.958 E-03

106

3.017 E-08 3.072 E-08 3.017 E-08 3.017 E-08 3.017 E-08 3.023 E-08 3.032 E-08 3.016 E-08 3.05 E-08 3.017 E-08

10"

3.555 E-17 3.555 E-17 3.555 E-17 3.552 E-17 3.555 E-17 3.548 E-17 3.537 E-17 3.554 E-17 3.54 E-17 3.555 E-17

103

1.253 E-04 1.250 E-04 1.249 E-04 1.249 E-04 1.249 E-04 1.252 E-04 1.251 E-04 1.249 E-04 1.25 E-04 1.249 E-04

107

7.776 E-11 7.778 E-11 7.778 E-11 7.779 E-11 7.759 E-11 7.ii2 E-11 7.i94 E-l 1 7.77 El1

7.8 E-11 7.778 E-11

__-~--. 10’2

3.525 E-17 3.525 E-17 3.525 E-17 3.522 E-17 3.525 E-17 3.532 E-17 3.5Oi E-17 3.524 E-li 3.51 E-li 3.525 E-Ii

108

1.034 E-11 1.034 E-11 1.034 E-11 1.033 13-11 1.034 E-III I.036 I~<-11 :I ,036 E- 1 I 1.034 E-11 I.03 E-1 I

1.034 15. I I

LO'"

3.234 E-J7 3.234 I<-17 3.234 E-l i 3.231 E-17 3.234 E-17 3.241 E-17 3.218 E-17 3.234 E-lIi 3.22 E-li

3.234 I<-li

0

0 0

24

0

0 0

TdAe :I: -y Decay &at. results (in MeV/sec) for a 235U fission pulse given at cooling times (ion1 I serolld to 10’3 seconds

chllputer code

AFPA CINDER-10 DCHAIN FISPG FISPIN INVENT KORIGEN MECXYCO ORIGEN-S PEPIN

100 101

1.732 E-02 8.312 E-03 1.735 E-02 8.304 E-03 1.734 E-02 8.303 E-03 1.734 E-02 8.303 E-03 1.734 E-02 8.303 E-03 1.735 E-02 8.320 E-03 1.734 E-02 8.306 E-03 1.734 E-02 8.301 E-03 1.73 E-02 8.31 E-03

1.734 E-02 8.303 E-03

Computer code

AFPA <:INI)ER-10 DCHAIN FISPG FISPIN 1NVENT KOR.IGEN MECCYCO ORIGEN-S PEPIN

~-.- colllyut~er code

AFPA C!INUER.-10 DCHAIN FISP6 FISPIN INVENT KORIGEM MISCCYCO ORIGEN-S I’FPlN J --

104 __~ 1.767 E-05 1.767 E-05 1.767 E-05 1.767 E-05 1.767 E-05 1.770 E-05 1.767 E-05 1.767 E-05 1.76 E-05 1.767 E-05

10”

1.255 E-11 1.225 E-11 1.225 E-11 1.224 E-11 1.225 E-11 1.228 E-11 1.228 E-11 1.225 E-11 1.23 E-11 1.226 E-11

I ! I I

105

6.755 E-07 6.758 E-07 6.756 E-07 6.753 E-07 6.756 E-07 6.769 E-07 6.792 E-07 6.755 E-07 6.76 E-07

6.756 E-07

10’0

1.685 E-14 1.685 E-14 1.685 E-14 1.684 E-14 1.685 E-14 1.690 E-14 1.696 E-14 1.685 E-14 1.69 E-14

1.685 E-14

106

8.650 E-08 8.651 E-08 8.650 E-08 8.650 E-08 8.650 E-08 8.664 E-08 8.697 E-08 8.647 E-08 8.65 E-08

8.650 E-08

I

1

I

I

10’1

8.921 E-27 8.921 E-27 8.921 E-27

8.921 E-27

8.830 E-27 8.921 E-27 8.85 E-27 8.921 E-27

102

1.924 E-03 1.926 E-03 1.925 E-03 1.925 E-03 1.925 E-03 1.929 E-03 1.926 E-03 1.925 E-03 1.92 E-03 1.925 E-03

103

1.344 E-04 1.342 E-04 1.342 E-04 1.342 E-04 1.342 E-04 1.344 E-04 1.342 E-04 1.342 E-04 1.34 E-04

1.342 E-04

10’

2.317 E-10 2.318 E-10 2.318 E-10 2.318 E-10 2.318 E-10 2.325 E-10 2.323 E-10 2.317 E-10 2.32 E-10 2.318 E-10

1012

6.416 E-27 6.416 E-27 6.416 E-27

6.416 E-27

5.350 E-27

6.36 E-27 6.416 E-27

108

2.369 E-11 2.369 E-11 2.369 E-11 2.367 E-11 2.369 E-11 2.373 E-11 2.374 E-11 2.368 E-11 2.37 E-11

2.369 E-11

10’3

2.376 E-28 2.376 E-28 2.3i6 E-28

2.376 E-28

2.351 E-28

2.36 E-28 2.376 E-28

25

Table 4: Total Decay Heat results (in MeV/sec) for a “‘U fission pulse given al. cooling t.imes from 1 second to lOl3 seconds

Computer code


Computer code


Computer code

AFPA CINDER-10 DCHAIN FISPF FISPIN INVENT KORIGEN MECCYCO OR.IGEN-S PEPIN

100

5.090 E-02 5.100 E-02 5.093 E-02 5.093 E-02 5.093 E-02 5.094 E-02 5.093 E-02 5.093 E-02 5.09 E-02 5.093 E-02

104

2.589 E-05 2.587 E-05 2.587 E-05 2.586 E-05 2.587 E-05 2.591 E-05 2.590 E-05 2.586 E-05 2.59 E-05 2.587 E-05

109

1.761 E-11 1.761 E-11 1.7Fl E-11 1.759 E-11 1.761 E-11 1.764 E-11 1.766 E-11 1.761 E-11 1.76 E-11

1.761 E-11

IO’

1.904 E-02 1.903 E-02 1.903 E-02 1.903 E-02 1.903 E-02 1.906 E-02 1.904 E-02 1.903 E-02 1.90 E-02

1.903 E-02

105

1.004 E-06 1.011 E-06 1.004 E-06 1.003 E-06 1.004 E-06 1.006 E-06 1.008 E-06 1.004 E-06 1.00 E-06

1.004 E-06

10’0

2.424 E-14 2.424 E-14 2.424 E-14 2.423 E-14 2.424 E-14 2.432 E-14 2.432 E-14 2.424 E-14 2.42 E-14

2.424 E-14

26

102

3.882 E-03 3.884 E-03 3.883 E-03 3.883 E-03 3.883 E-03 3.890 E-03 3.885 E-03 3.882 E-03 3.88 E-03

3.883 E-03

106

1.167 E-07 1.172 E-07 1.167 E-07 1.167 E-07 1.167 E-07 1.169 E-07 1.173 E-07 1.166 E-07 1.17 E-07

1.167 E-Oi

IO”

3.555 E-17 3.555 E-17 3.555 E-17 3.552 E-17 3.555 E-17 3.562 E-17 3.556 E-17 3.554 E-17 3.54 E-17

3.555 E-17

103 -

2.597 E-04 2.592 E-04 2.591 E-04 2.591 E-04 2.591 E-04 2.596 E-04 2.593 E-04 2.591 E-04 2.59 E-04

2.591 E-04 I I I I

10’

3.095 E-10 3.095 E-10 3.095 E-10 3.096 E-IO 3.096 E-10 3.105 E-IO 3.101 E-10 3.095 E-IO 3.10 E-10

3.095 E-IO

10’2

3.525 E-17 3.525 E-17 3.525 E-17 3.522 E-li 3.525 E-17 3.532 E-17 3.526 E-17 3.524 E-17 3.51 E-Ii

3.525 E-17

IO”

3.403 I$-1’1 3.403 12,. I I 3.403 E.11~ 3.400 13-11 3.403 E-l 1 3.409 15-I 1 3.414 E-II 3.403 IS-1 I 3.40 E-l 1~

3.403 E-l 1~

10’3

3.234 E-17 3.234 IS-17 3.234 E-Ii 3.231 E-Ii 3.234 E-Ii 3.241 E-Ii 3.235 E-17 3.234 13-17 3.22 E-l.7

3.234 I<-17

0

0 0

Table 5: Fission uroduct contribution (in %1 to the total decay heat for a 235U fission pulse after 10 second cooling time

0

0 0

Chquter code ‘Yh

XFPA 1.84 CINDER-10 1.85 DC!HAIN 1.84 FISPG 1.85 FISPIN 1.85 INVENT 1.84 KOR.IC:EN 1.84 MEC!C:YCO 1.84 ORIGEN-S 1.85 PEPIN 1.84

Clomputer code

A FPA CINDER-10 DCHAIN FISP6 FISPIN INVENT KOILIGEN MECC!YC!O ORIGEN-S PEPIN

‘%I) -

1.93 1.93 1.93 1.93 1.93 1.93 1.93 1.93 1.94 1.93

I.2 I

mj- Tq

8.76 8.99 a.77 9.00 8.77 9.00 a.77 9.00 8.77 ~9.00 a.77 8.99 8.76 8.99 8.76 9.00 8.79 9.00 a.77 9.00

,=Sb

1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.03 1.03

II I

.-Sb - 1.72 1.72 1.72 1.72 1.72 1.72 1.72 1.72 1.72 1.72

Tq L!zc=zz 1.96 1.96 1.96 1.96 1.96 1.96 1.96 1.96 1.97 1.96

-Sb

3.77 3.77 3.77 3.77 3.77 3.77 3.77 3.77 3.77 3.77

‘35Te - 15.24 15.24 15.24 15.24 15.25 15.24 15.24 15.24 15.26 15.24

I 1 I I

‘37Xe 1.27 1.28 1.27 1.27 1.28 1.28 1.27 1.28 1.28 1.27

‘3GTe - 10.67 10.57 10.57 10.57 10.57 10.57 10.56 10.57 10.58 10.57

I 1 I I

‘=Xe

10.86 10.86 10.86 10.86 10.86 10.86 10.87 10.86 10.89 10.86

‘4OXe - 14.67 14.68 14.68 14.68 14.68 14.69 14.68 14.69 14.68 14.68

L40~s ziIzzz= 6.82 6.83 6.83 6.83 6.83 6.83 6.84 6.83 6.84 6.83

27

Table 6: Fission product contribution (in %) to the total decay heat for a 235U fission pulse after lo5 seconds cooling time

Computer code 11 131mTe 1, ‘=Te

AFPA 11 2.23 1 2.72 CINDER-IO DCHAIN FISPG FISPIN INVENT KOR.IGEN MECCYCO ORIGEN-S PEPIN

2.21 2.70 2.23 2.72 2.23 2.i2 2.23 2.72 2.23 2.72 2.22 2.75 2.23 2.72 2.23 2.72 2.23 2.72

1311 -iy xy *35*

Ecz=zzz - - - 1.18 23.20 25.47 18.69 1.19 23.05 25.31 18.56 1.19 23.20 25.47 18.69 1.19 23.20 25.47 18.68 1.19 23.20 25.47 18.69 1.19 23.20 25.46 18.F9 1.19 23.49 25.36 18.61 1.19 23.20 25.47 18.F9 1.20 23.30 25.60 18.80 1.19 23.20 25.4i 18.69

5 4.10 4.08 4.10 4.10 4.10 4.10 4.09 4.1~0 4.12 4.10

Table 7: Fission product contribution (in %) to the total decay heat. for a 235U fission pulse afkr 10” seconds cooling time

Computer code


13’CS

22.91 22.92 22.91 22.91 22.92 22.91 22.92 22.91 22.90 22.91

137711ga

- 77.09 77.08 77.09 77.09 77.08 77.09 77.08 77.09 77.27 77.09

0

0 0

28

-' Table 8: fl Decay Heat results (in M&V/sex) for a 3~10~ seconds irradiation given at cooling times from 1 second to 1013 seconds

0

0 0

Computer code IO0 AFPA 1.675 Et15 CINDER-IO 1.680Et15 UNDER 1.666 Et15 DCXIAIN 1.676Et15 FISPG 1.675 Et15 FISPIN 1.675Et15 INVENT 1.679 Et15 KORIGEN 1.676 Et15 MECCYCO 1.675 Et15 ORIGEN-S 1.67 Ef15 PEPIN 1.676 Et15

Computer code AFPA CINDER-10 (!INDER DCXAIN FISPG FISPIN ItiVtiN'I KORIGEN MECXYCO OR.lGEN-S PEPIN

Computer code AFPA CXNDEIL-10 CJINDER, DCXAIN FISP6 FISPIN INVENT KORiGEN MECXYCO ORIGEN-S PEPIN

I

I

104 2.274Et14 2.319Et14 2.242 Et14 2.274Et14 2.275 Et14 2.274Et14 2.284Et14 2.279Et14 2.273 Et14 2.28 Et14 2.274Et14

log 1.985 Et11 1.985 Et11 1.961Etll 1.985Etll 1.985 Et11 1.985Etll 1.988 Et11 1.985 Et11 1.985 Et11 1.98 Et11 1.985 Et11

I I I I

10 1.491Et15 1.495 Et15 1.482Et15 1.491Et15 1.491Et15 1.491Et15 1.494 E+15 1.491Et15 1.491Et15 1.49 E+15 1.491Et15

105 1.281Et14 1.321Et14 1.263 Et14 1.282 EC14 1.282Et14 1.282 Et14 1.288 E-t14 1.285 Et14 1.281Et14 1.29 Et14 1.282Et14

1010 2.732Et08 2.732E-k08 2.702Et08 2.732 Et08 2.733 Et08 2.732EtOB 2.740EtOB 2.731E+08 2.731 E~t08 '2.73 Et08 2.732EtOB

102 103 l.O04E+14 5.625 Et14 1.009Et15 5.656 Et14 9.971Et14 5.561Et14 1.004 Et15 5.612 Et14 1.004 Et15 5.612 Et14 1.004Et15 5.611Et14 1.006 Et15 5.627 Et14 1.005 Et15 5.617 Et14 1.004 Et15 5.610Et14 1.00 Et15 5.6 Et14 1.004 Et15 5.612 Et14

106 4.707 Et13 4.728 Et13 4.700 Et13 4.709 Et13 4.711Et13 4.710 Et13 4.722 Et13 4.710Et13 4.709Et13 4.7 Et13

4.709 Et13

10" 2.796 Et05 2.797Et05 2.701Et05 2.795 Et05 2.796 Et05 2.796 Et05 2.793 Et05 2.801Et05 2.796 Et05 2.78 Et05 2.795 E+05

29

10' 8.483Etll 8.487Etll 8.511Etll 8.485 Et11 8.484Etll 8.484Etll 8.518Etll 8.543E+ll 8.485Etll 8.5 Et11

8.486Etll

2.772 Et05 2.773Et05 2.678Et05 2.771Et05 2.772Et05 2.772 Et05 2.769Et05 2.777E+05 2.573E+05 2.76 E+05 2.772 Et05

lo8 5.010Etll 5.011Etll 4.993 Et11 5.010Etll 5.009Etll 5.010Etll 5.025 Et11 5.032Etll 5.010Etll 5.0 Et11

5.011Etll

10'3 2.544 Et05 2.545 Et05 2.458Et05 2.543Et05 2.543Et05 2.543 Et05 2.540 Et05 2.548Et05 2.544E+05 2.53 Et05 2.543Et05

Table 9: y Decay Heat results ( in MeV/sec) for a 3x10’ seconds irradiation given al: cooling times from 1 second to lOI seconds

chllputer code

AFPA CINDER:10 CINDER DCHAIN FISPS FISPIN INVENT KORIGEN MECCYCO ORIGEN-S PEPIN

Computer code

AFPA CINDER-IO C!INDER DCHAIN FISPG FISPIN INVENT KORIGEN MECCYCO ORIGEN-S PEPIN

Computer cod’

AFPA CINDER-IO CINDER DCHAIN FISPF FISPIN INVENT KORIGEN MEC!C!YCO ORIGEN-S PEPIN

100

2.146 Et15 2.147 Et15 2.133 Et15 2.147 E+15 2.147 Et15 2.146 Et15 2.153 Et15 2.148 E+15 2.146 Et15 2.15 Et15 2.147 Et15

104

5.956 Et14 5.957 Et14 5.881 Et14 5.957 Et14 5.961 Et14 5.956 Et14 5.993 Et14 5.976 Et14 5.955 E+l4 5.99 Et14

5.957 Et14

IO”

4.546 Et11 4.546 Et11 4.454 Et11 4.546 Et11 4.546 Et11 4.546 E+ll 4.555 Et11 4.546 Et11 4.546 Et11 4.55 Et11

4.546 Et11

IO’

2.024 Et15 2.024 Et15 2.011 Et15 2.024 Et15 2.024 Et15 2.023 Et15 2.030 Et15 2.026 Et15 2.024 Et15 2.02 Et15

2.024 Et15

105

3.549 E+l4 3.551 Et14 3.507 Et14 3.552 Et14 3.555 Et14 3.551 Et14 3.576 Et14 3.564 Et14 3.551 Et14 3.57 Et14

3.552 Et14

10’0

6.250 E+08 6.250 Et08 6.131 Et08 6.250 Et08 6.252 Et08 6.250 Et08 6.270 Et08 6.250 Et08 6.250 Et-08 6.25 Et08

6.250 Et08

30

102

1.597 Et15 1.597 Et15 1.585 Et15 1.597 Et15 1.598 E+l5 1.597 Et15 1.602 Et15 1.599 Et15 1.596 Et15 1.60 Et15

1.597 Et15

IO”

1.399 Et14 1.400 Et14 1.393 Et14 1.400 Et14 1.402 Et14 1.400 Et14 1.404 Et14 1.400 Et14 1.400 Et 14 1.40 Et14

1.400 Et14

10”

3.323 E-04 3.345 E-04 3.345 E-04 3.346 E-04

3.345 E-04

3.351 E-04 3.345 E-04 3.32 E-04

3.346 E-04

103

1.168 E-t-15 1.16.5 E-t15 1.154 ES-15 1.165 E+15 1.165 Et15 1.165 Et,15 1.169 Et15 l.lFi Et15 1.165 E+l5 1.17 F~t15 1.165 Et15

IO’

4.253 Et12 4.255 Et12 4.305 Et12 4.254 E-1-12 4.253 Et12 4.253 Et12 4.278 Et12 4.310 Et12 4.254 E-112 4.29 E+l2 4.255 Et12

10’2

2.406 E-04 2.406 E-04 2.406 E-04 2.406 E-04

2.406 E-04

2.410 E-04

2.38 E-04 2.406 E-04

10s

1.991 Et12 1.992 Et12 2.002 E-1,. I2 1.992 E+~J2 1.991 ES12 1.991 Et12 2.001 Ei-12 2.013 Et12 1.991 EPIC 12 2.01 IQ12 1.992 E-i 12

1.0’3

s.910 E-OG- 8.909 E-06 8.914 E-06 8.909 E-06

8.909 E-06

8.923 E-06

8.83 E-06 8.910 E-06 _~__

‘IX&z 10: Total Decay Heat results (in MeV/sec) for a 3~10~ seconds irradiation given at cooling times from 1 second to 1Ol3 seconds

Computer code

AFPA CINDER-10 CINDER DCHAIN FISPG FISPIN INVENT KORIGEN ,MECCYCO ORZGEN-S PEPIN -

Computer code

AFPA C!INDER:lO CINDER. DC!HAIN FISPG FISPIN INVENT KORIGEN MECCYCO OIUGEN-S 1’ WIN

Computer code

>.FPA CINDER-10 CINDER. DCIIAIN FISPG FISPIN INVENT KORIGEN MECCYCO ORIGEN-S PEPIN --..~.__

100 3.821 Et15 3.827 Et15 3.800 Et15 3.823 E+15 3.822 Et15 3.821 E+15 3.832 Et15 3.824 Et15 3.821 Et15 3.820 Et15 3.822 Et15

10’ 3.514 Et15 3.519 Et15 3.493 E+15 3.515 Et15 3.515 Et15 3.514 E+15 3.524 Et15 3.517 Et15 3.514 Et15 3.510 Et15 3.515 Et15

104 105

109

6.531 Et11 6.531 Et11 6.415 Et11 6.531 Et11 6.530 Et11 6.531 Et11 6.543 Et11 6.532 Et11 6.531 Et11 6.530 Et11 6.531 Et11

8.981 E+08 8.982 Et08 8.833 Et08 8.981 Et08 8.984 Et08 8.981 Et08 9.011 Et08 8.982 Et08 8.981 Et08 8.980 Et08 8.981 E-CO8

lo2


106 1.870 E+14 1.873 E+14 1.863 Et14 1.871 Et14 1.873 Et14 1.871 Et14 1.877 Et14 1.872 E+14 1.870 Et14 1.870 Et14 1.871 Et14

10’1

2.796 Et05 2.797 Et05 2.701 Et05 2.795 Ef05 2.796 Et05 2.796 Et05 2.793 Et05 2.801 Ef05 2.796 E-t05 2.780 Et05 2.795 E-CO5

103 1.730 Et15 1.730 Et15 1.710 Et15 1.726 Et15 1.726 Et15 1.726 Et15 1.732 Et15 1.729 Et15 1.726 Et15 1.730 Et15 1.726 Et15

10’ 5.101 Et12 5.104 Et12 5.156 Et12 5.103 Et12 5.102 Et12 5.102 Et12 5.130 Et12 5.165 Et12 5.103 Et12 5.140 Et12 5.104 Et12

1012

2.772 Et05 2.773 Et05 2.678 Et05 2.771 Et05 2.772 Et05 2.772 Et05 2.769 Et05 2.777 Et05 2.773 Et05 2.760 Et05 2.771 E+05

108 2.492 Et12 2.493 Et12 2.501 Et12 2.493 Et12 2.492 Et12 2.492 Et12 2.503 Et12 2.517 Et12 2.493 Et12 2.510 Et12 2.493 E+12

10’3


31

Table 11: Fission product contribution (in %) to the total decay heat for a 3x10’ seconds irradiation after 1 second cooling time

-- I ?I ‘3GTe

2.65 2.65 2.ti7 2.65 2.65

1

2.65 2.65 2.65 2.65 2.64 2.65

Computer code ‘=Sb

AFPA 1.55 CINDER-10 1.55 CINDER 1.56 DCHAIN 1.56 FISPG 1.56 FISPIN 1.55 INVENT 1.55 KORIGEN 1.55 MECCYCO 1.55 OR.IGEN-S 1.55 PEPIN 1.56

Wb zzzzzzc 2.89 2.88 2.90 2.89 2.88 2.89 2.89 2.88 2.89 2.88 2.89

l=Sb

2.39 2.39 2.41 2.39 2.39 2.39 2.39 2.39 2.39 2.39 2.39 7 !

1361

3.88 3.87 3.86 3.88 3.87 3.88 3.87 3.87 3.88 3.87 3.88

‘%S

8.17 8.16 8.12 8.17 8.17 8.17 8.16 8.16 8.17 8.17 8.16

-- -=Te

2.00 1.99 1.98 2.00

2.00 2.00 2.00 2.00 2.00 1.99 2.00

- .=I

i.55 1.54 i.57 I.55 ‘.55 8.55 ‘.54 ‘.55 ‘.55 ‘.55 ‘.55

IT 1 1, 1, 1, 1,

r

1. 1. 1. 1. 1. 1.

L?9Cs

4.20 4.20 4.21 4.20 4.20 4.20 4.20 4.20 4.20 4.19 4.20

.=mTe - 1.80 1.79 1.81 1.80 1.80 1.80 1.79 1.79 1.80 1.80 1.80

‘34Te ‘3STe

2.24 3.63 2.24 3.63 2.24 3.62 2.24 3.63 2.24 3.63 2.24 3.63 2.24 3.63 2.24 3.63 2.24 3.63 2.24 3.64 2.24 3.63 0

133I 1341

2.22 7.98 2.21 7.91 2.13 8.03 2.22 7.98 2.21 7.98 2.22 7.98 2.21 7.91 2.21 7.98 2.22 7.98 2.21 7.98 2.22 7.98

1321

Yzz=ZZ

3.89 3.89 3.91 3.89 3.89 3.89 3.89 3.89 3.89 3.90 3.89

GmI

.53

.53

.54

.53

.53

.53 ,53 ,53 ,53 ,53 ,53 -

,371 1381 ‘3’X‘Z

2.49 1.37 3.87 2.49 1.37 3.8i 2.50 1.38 3.86 2.49 1.37 3.87 2.49 1.37 3.87 2.49 1.37 3.87 2.49 1.37 3.8i 2.49 1.37 3.8i 2.49 1.37 3.87 2.49 1.3i 3.87 2.49 1.37 3.87

‘“8Xe

3.92 3.92 3.90 3.92 3.92 3.92 3.92 3.92 3.92 3..93 3.92

Computer code

AFPA CINDER-10 CINDER DCHAIN FISPG FISPIN INVENT KORIGEN MECCYCO ORIGEN-S PEPIN @

0 ‘4OXe - 2.83 2.83 2.85 2.83 2.83 2.83 2.83 2.83 2.83 2.83 2.83

l4OBa

1.01 1.01 1.01 1.01 1.01 1.01 1.01 1.01 1.01 1.01 1.01

Computer code ‘3”Xe

AFPA 4.52 CINDER-10 4.52 CINDER 4.52 DCHAIN 4.52 FISPG 4.52 FISPIN 4.52 INVENT 4.52 KORlGEN 4.52 MECCYCO 4.52 ORIGEN-S 4.53 PEPIN 4.52

‘WS

7.17 7.16 7.21 7.17 7.17 7.17 7.17 7.17 7.17 7.17 7.17

‘39Ba

2.01 2.00 2.01 2.01 2.01 2.01 2.01 2.00 2.01 2.01 2.01

,4OLa

5.86 5.85 5.81~ 5.85 5.85 5.86 5.94 5.92 5.86 5.99 5.85

32

l

a e

Table 12: Fission product contribution (in %) t,o the total decay heat for in 3~10~ seconds irradiation after lo4 seconds cooling time

Ckmputer code

~FPA UNDER-10 UNDER. ~DC:HAIN FISPG FISPIN INVENT KORIGEN MECCYCO ORIGEN-S PEPIN

,32Te

2.10 2.09 2.13 2.10 2.10 2.10 2.09 2.09 2.10 2.09 2.10

11 Computer code

11 AFPA UNDER-10 CINDER DC:HAIN FISPG FISPIN INVENT KORIGEN ME’XYCO ORIGEN-S PEPIN

‘33Xe zzYzzz= 1.83 1.82 1.85 1.83 1.82 1.83 1.82 1.82 1.83 1.75 1.83

133rnTe 1311

1.05 2.18 1.04 2.17 1.06 2.20 1.05 2.18 1.05 2.17 1.05 2.18 1.04 2.16 1.04 2.li 1.05 2.17 1.04 2.14 1.05 2.18

r

I

=Xe zz?=zzz 1.81 1.80 1.72 1.81 1.83 1.81 1.81 1.81 1.81 1.80 1.81

33

‘38CS

1.84 1.83 1.85 1.84 1.84 1.84 1.84 1.84 1.84 1.84 1.84

Ty 1331

- =zz=czz 17.79 9.62 17.70 9.57 18.03 9.27 17.80 9.62 17.78 9.61 17.79 9.62 17.73 9.58 17.74 9.59 17.79 9.62 17.65 9.56 17.80 9.F2

‘39Ba - 2.61 2.60 2.64 2.61 2.61 2.61 2.60 2.61 2.61 2.60 2.61

71 I

1341

10.08 10.02 10.21 10.08 10.07 10.08 10.04 10.05 10.08 10.02 10.08

.4OBa

4.65 4.62 4.71 4.F5 4.65 4.F5 4.63 4.63 4.65 4.63 4.F5

Tay - 13.46 13.38 13.50 13.46 13.45 13.46 13.40 13.41 13.46 13.42 13.46

‘40La - 27.17 27.02 27.16 27.16 27.15 27.18 27.43 27.39 27.17 27.57 27.16

Table 13: Fission product contribution (in %) to the t.otal decay heat for a 3x 10’ seconds irradiation after 10’ seconds cooling time 0

1 Computer code %A

49.36 49.38 50.44 49.37 49.36 49.36 49.50 49.85 49.36 49.80 49.38

34

0 e

ANNEX1

NEANDC-246 'U' NEACRP-303 'L'

INTERNATIONAL COMPARISON STUDY

OF CODES USED IN DECAY HEAT CALCULATIONS

Bernard Duchemin, CEA Saclay Claes Nordborg, NEA Data Bank

25th November 1988

1. INTRODUCTION

Following a discussion at the NEACRP/NEANDC Specialists' Meeting on Data for Decay Heat Predictions, held at Studsvik, Sweden, 7th-10th September 19871,' it was decided to,perform an inter-comparison of codes used in decay heat calculations. It tias shown that the existing codes could not reproduce the experimental data .at short cooling times. The main reason for this discrepancy, was thought to be due to lack of good data for short lived fission products. It was nevertheless felt, that a comparison of the summation codes, both analytical and numerical, for the calculation of decay heat would be very useful in order to verify the computational aspect of the problem. The following ttio benchmark specifications were agreed upon.

2. SPECIFICATION

Benchmark no 1:

'23~s tem~: U-235 fission' pulse

Input Data: Decay Data: The heavy mass peak A=131-140. The data have been extracted from the Evaluated Nuclear Structure Data File (ENSDF) and translated into the ENDF-5 format at the NEA Data Bank, using a new version of the code RADLST. Delayed neutron data are also included. (File no 1 on tape)

Fission Yields: The file contains data for U-235 and in the ENDF-5 format. Independent yields with uncertainties are given at thermal energy. The corresponding cumulative yields, without uncertainties are also included. (File no 2 on tape)

35

Benchmark no 2:

System: Long irradiation ( 3.0 * IO7 seconds) of fuel elements com- posed of 100% U-235. It is assumed that no burn-up will take place.

Input Data: Decay Data: Same as for benchmark no 1.

Fission Yields: Same as for benchmark no 1.

Neutron flux: Maxwellian 2(600° K) spectrum of 5.0*1013 neutrons/cm *second

Fission rate:

Capture data:

1.25 * 1015 fissions/second

The average one-group capture cross sections has been given in file number 3 on the tape. They have been calculated using the following formula : 0

< 0 > = -E- 7% 2g3 --- + cap

sc*1 1.128 T cap

where T = 600’ K, SC = 0.3 (Epithermal to thermal flux ratio), and I is the capture resonance integral. cap

The data are given in free format, one isotope per line. Each line contains the following information: isotope proton number (Z), isotope mass (A), and the one-group capture cross section.

3. WHAT TO CALCULATE 0

The following quantities should be calculated for both benchmark 1 and 2:

A. Decay heat for beta, gamma, and beta + gamma in MeV/second, for cooling

times: 1, 10, 102, 103,.........1013 seconds. (Every decade).

B. List of fission products and their contribution (in per-cent) to the decay heat at each of the above mentioned cooling times. Only those isotopes contributing more than 1.0 % to the decay heat should be specified.

All calculated values should preferable be given with uncertainties. The answers should contain a reference to what computer code was used, and on what computer it was run. The CPU time used could also be of interest.

36

,

4. PARTICIPATION AND RESULTS

Those interested in participating and receiving the input data on tape, should contact:

Claes Nordborg NEA Data Bank Bat. 445 91191 GIF-SW&YVETTE CEDEX FRANCE

Telephone: l-69086094 Telex: NEADATA 690920F Telefax: 1-69413965 Computer network: NORDBORG at

FRNEAB51 (EARN/BITNET)

The results must be returned by 5 May 1989 to the above mentioned address.

31

RESULTS OF BENCHMARK NO 1

NAME : ................................................................

INSTITUTE : ...............................................................

CODE NAME AND TYPE (ANAL. OR NUMER.): .....................................

CODE REFERENCE : ..........................................................

COMPUTER AND CPU-TIME USED : ..............................................

NOTE!! THE CONCENTRATION OF FISSION PRODUCTS SHOULD BE GIVEN SEPARATELY. '

DECAY BEAT RESULTS

COOLING BETA dBETA GAMMA dGAMMA BETA+GAMMA d(B+G) seconds MeV/sec % MeV/sec % MeV/sec %

10 1

10 2

10 3

10 4

10 5

10 6

10 ’

10 *

10 9

lOI

1011

1012

1013

38

RESULTS OF BENCHMARK NO 2

NAME : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

INSTITUTE : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CODE NAME AND TYPE (ANAL. OR NUMER.) : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CODE REFERENCE : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COMPUTER AND CPU-TIME USED : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

NOTE!! THE CONCENTRATION OF FISSION PRODUCTS SHOULD BE GIVEN SEPARATELY.

DECAY BEAT RESULTS

COOLING BETA dBETA GAMMA dGAMMA BETA+GAMMA d(B+G) seconds MeV/sec % MeV/sec % MeV/sec %

10 O

10 1

10 2

10 3

10 4

10 g

lOlO

1011

1o12

lo13 39

Documents

DECAY HEAT CALCULATION - Nuclear Energy Agency (NEA)