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Comparison of European computer codes relative to the aerosol behaviour in PWR containment buildings during severe core damage accidents

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Nuclear energy and safety

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Publié par
Nombre de lectures 26
Langue English
Poids de l'ouvrage 1 Mo

£UR A4.-ASÌJ
Commission of the European Communities
nuclear science and technology
COMPARISON OF EUROPEAN COMPUTER CODES
RELATIVE TO THE AEROSOL BEHAVIOR
IN PWR CONTAINMENT BUILDINGS
DURING SEVERE CORE DAMAGE ACCIDENTS
Blow-up from microfiche original Commission of the European Communities
nuclear science and technology
COMPARISON OF EUROPEAN COMPUTER CODES
RELATIVE TO THE AEROSOL BEHAVIOR
IN PWR CONTAINMENT BUILDINGS
DURING SEVERE CORE DAMAGE ACCIDENTS
Jean FERMANDJIAN
CEA/IPSN/DAS/STAS/SASC
CEN/FAR
B.P.6 ­ F­92265 Fontenay­aux­Roses Cedex (FRANCE)
Contract No. ECI­1414­B­7221­85­F
FINAL REPORT
(November 1986)
Directorate­General Science, Research and Developme itpADI ¡ Π|ΡΓ)Ρ Rihlinfh
1987 N.äSJR 11154 EfJ
CL Published by the
COMMISSION OF THE EUROPEAN COMMUNITIES
Directorate-General
Telecommunications, Information Industries and Innovation
BAtiment Jean Monnet
LUXEMBOURG
LEGAL NOTICE
Neither the Commission of the European Communities nor any person acting on behalf
of then is responsible for the use which might be made of the following
information
© ECSC—EEC—EAEC Brussels - Luxembourg, 1987 III
¡ ABSTRACT ¡
The prediction of the behavior of nuclear aerosols, associated
with postulated PWR accidents, in the reactor containment building, is
necessary for the assessment of radiological consequences, and hence it is
an important aspect of reactor safety evaluation.
The present study concerns a comparative exercise, performed
within the framework of the Commission of the European Communities - Divi­
sion of Safety of Nuclear Installations -, of the computer codes (AEROSIM-M,
UK ; AER0S0LS/B1, France ; CORRAL-2, CEC and NAUA Mod5, Germany) used in
order to assess the aerosol behavior in PWR containment buildings during
severe core damage accidents (with steam condensation onto the particles).
The previous CEC aerosol code comparison exercise performed in
1984 within the framework of LMFBR safety, without steam condensation onto
the particles, indicated that the results of discrete codes were very
similar. The present study shows that the accounting for the steam
condensation onto the particles does not lead to large discrepancies
concerning the (integrated) aerosol leaked mass despite the differences in
the kinetics of aerosol behavior.
, The large discrepancies between the results of the discrete codes
and of the empirical approach code CORRAL-2, especially concerning the
instantaneous and integrated leaked masses, justify the development of
discrete aerosol behavior codes. OUTLINE
ABSTRACT III
I - INTRODUCTION 1
II - BRIEF DESCRIPTION OP THE CODES 2
III - DEFINITION OF THE BENCHMARK CALCULATIONS 5
. SURRY 1 CASE
. SIMPLE CASE
. SENSITIVITY ANALYSIS 6
IV - RESULTS OBTAINED 7
. MASS CONCENTRATION 8
. SETTLED MASS 10
. DIFFUSED MASS
. LEAKED MASS1
. MASS MEDIAN RADIUS2
. GEOMETRICAL STANDARD DEVIATION3
. PARTICLE SIZE DISTRIBUTION4
. MASS BALANCE5
V - CONCLUSION7
FUTURE WORK 18
ACKNOWLEDGEMENTS
REFERENCES9
TABLES 21
FIGURES 43 VII
TABLES
Tabi« I ­ Physical processes taken Into account by the CORRAL­2,
AEROSIM­M, NAUA Mod5 and AER0S0LS/B1 computer codes
Table II ­ Calculation methods used by the CORRAL­2, AEROSIM­M, NAUA Mod5
and AER0S0LS/B1 computer codes
Table III ­ Timing of predicted events for S2CD
Table IV ­ Input data for PUR accident sequence (SURRY 1)
Table V ­ Aerosol source rate for S2CD sequence (SURRY 1)
Table VI ­ Thermohydraulic data for S2CD sequence (SURRY 1)
Table VII ­ c data for S2CD sequence (SURRY 1)
Table VIII ­ Discretisation of the particle sise attribution used in various
computer models
Table IX ­ Input data for the simple case
Table X ­ Mass balance at t ­ 2 days ­ SURRY 1 (S2CD sequence) ­ Dry
case
Table XI ­ Mass balance at t ­ 3,300 seconds ­ SURRY 1 (S2CD sequence) ­
Wet case
Table XII ­ Mass balance at t ­ 42,720 seconds ­ SURRY 1 (S2CD sequence) ­
Wet case
Table XIII ­ Mass balance at t ­ 2 days ­ SURRY 1 (S2CD sequence) ­ Wet
case
Table XIV ­ Diffused aerosol masses on the walls of the RCB ­ SURRY 1 (S2CD
sequence)
Table XV ­ Leaked aerosol masses at t ­ 2 days ­ SURRY 1 (S2CD sequence)
Table XVI ­ Mass balance at t ­ 600 seconds ­ Simple case ­ Dry
Table XVII ­ Mass balance at t ­ 300 seconds ­ Simple case ­ Wet
Table XVIII­ Mass balance at t ­ 600 seconds ­ Simple case ­ Wet
Table XIX ­ Diffused aerosol masses on the walls of the containment vessel
at t ■ 600 seconds ­ Simple case
Table XX ­ Leaked aerosol masses at t · 600 seconds ­ Simple case