Preliminary analysis of the post-disassembly expansion phase and structural response under unprotected loss of flow accident in prototype sodium cooled fast reactor

For the prototype sodium-cooled fast reactor, MONJU, the mechanical energy and structural response under energetics caused by neutronic power excursion during Unprotected Loss of Flow (ULOF) accident were preliminarily evaluated. In the first licensing of MONJU, pressure-volume relation (P-V relatio...

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Autores principales: Yuichi ONODA, Ken-ichi MATSUBA, Yoshiharu TOBITA, Tohru SUZUKI
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Publicado: The Japan Society of Mechanical Engineers 2017
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spelling oai:doaj.org-article:029d69babe974376bf8abaf7ec1bda132021-11-26T07:03:57ZPreliminary analysis of the post-disassembly expansion phase and structural response under unprotected loss of flow accident in prototype sodium cooled fast reactor2187-974510.1299/mej.16-00597https://doaj.org/article/029d69babe974376bf8abaf7ec1bda132017-03-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/mej/4/3/4_16-00597/_pdf/-char/enhttps://doaj.org/toc/2187-9745For the prototype sodium-cooled fast reactor, MONJU, the mechanical energy and structural response under energetics caused by neutronic power excursion during Unprotected Loss of Flow (ULOF) accident were preliminarily evaluated. In the first licensing of MONJU, pressure-volume relation (P-V relation) was evaluated based on the maximum theoretical work energy possible for an expanding core. It was adopted in the structural response analysis of the reactor vessel as the input. The maximum theoretical work energy is called Fuel Vapor Work Potential (FVWP) in this paper. In the successive studies of the energetics, mechanical energy was evaluated with the code in which mechanistic modelling of core expansion was implemented and this might reduce the Actual Work Potential (AWP) by an order of magnitude below FVWP. In order to evaluate the realistic structural response of the reactor vessel using AWP, method to convert the AWP to the P-V relation is necessary. Therefore, we developed the method to obtain realistic P-V relation based on the AWP by tracing the surface of the expanding core, and then we evaluated the mechanical energy and structural response under energetics during ULOF accident in MONJU using the developed method. The AWP is evaluated to 3 MJ based on the result of the latest ULOF analysis in which FVWP was evaluated to 30MJ, and sodium slug does not impact on the lower surface of the shield plug and no residual strain of the reactor vessel is evaluated. When FVWP is assumed to be 500 MJ as a hypothetical condition covering the conservative energy production, corresponding AWP is evaluated to 33 MJ. In this case, sodium slug impacts on the lower surface of the shield plug and residual strain of the reactor vessel of 0.008% at the maximum is evaluated, however the integrity of the primary boundary is still maintained.Yuichi ONODAKen-ichi MATSUBAYoshiharu TOBITATohru SUZUKIThe Japan Society of Mechanical Engineersarticlesodium-cooled fast reactorsevere accidentunprotected loss of flowenergeticssimmer-ivautodynMechanical engineering and machineryTJ1-1570ENMechanical Engineering Journal, Vol 4, Iss 3, Pp 16-00597-16-00597 (2017)
institution DOAJ
collection DOAJ
language EN
topic sodium-cooled fast reactor
severe accident
unprotected loss of flow
energetics
simmer-iv
autodyn
Mechanical engineering and machinery
TJ1-1570
spellingShingle sodium-cooled fast reactor
severe accident
unprotected loss of flow
energetics
simmer-iv
autodyn
Mechanical engineering and machinery
TJ1-1570
Yuichi ONODA
Ken-ichi MATSUBA
Yoshiharu TOBITA
Tohru SUZUKI
Preliminary analysis of the post-disassembly expansion phase and structural response under unprotected loss of flow accident in prototype sodium cooled fast reactor
description For the prototype sodium-cooled fast reactor, MONJU, the mechanical energy and structural response under energetics caused by neutronic power excursion during Unprotected Loss of Flow (ULOF) accident were preliminarily evaluated. In the first licensing of MONJU, pressure-volume relation (P-V relation) was evaluated based on the maximum theoretical work energy possible for an expanding core. It was adopted in the structural response analysis of the reactor vessel as the input. The maximum theoretical work energy is called Fuel Vapor Work Potential (FVWP) in this paper. In the successive studies of the energetics, mechanical energy was evaluated with the code in which mechanistic modelling of core expansion was implemented and this might reduce the Actual Work Potential (AWP) by an order of magnitude below FVWP. In order to evaluate the realistic structural response of the reactor vessel using AWP, method to convert the AWP to the P-V relation is necessary. Therefore, we developed the method to obtain realistic P-V relation based on the AWP by tracing the surface of the expanding core, and then we evaluated the mechanical energy and structural response under energetics during ULOF accident in MONJU using the developed method. The AWP is evaluated to 3 MJ based on the result of the latest ULOF analysis in which FVWP was evaluated to 30MJ, and sodium slug does not impact on the lower surface of the shield plug and no residual strain of the reactor vessel is evaluated. When FVWP is assumed to be 500 MJ as a hypothetical condition covering the conservative energy production, corresponding AWP is evaluated to 33 MJ. In this case, sodium slug impacts on the lower surface of the shield plug and residual strain of the reactor vessel of 0.008% at the maximum is evaluated, however the integrity of the primary boundary is still maintained.
format article
author Yuichi ONODA
Ken-ichi MATSUBA
Yoshiharu TOBITA
Tohru SUZUKI
author_facet Yuichi ONODA
Ken-ichi MATSUBA
Yoshiharu TOBITA
Tohru SUZUKI
author_sort Yuichi ONODA
title Preliminary analysis of the post-disassembly expansion phase and structural response under unprotected loss of flow accident in prototype sodium cooled fast reactor
title_short Preliminary analysis of the post-disassembly expansion phase and structural response under unprotected loss of flow accident in prototype sodium cooled fast reactor
title_full Preliminary analysis of the post-disassembly expansion phase and structural response under unprotected loss of flow accident in prototype sodium cooled fast reactor
title_fullStr Preliminary analysis of the post-disassembly expansion phase and structural response under unprotected loss of flow accident in prototype sodium cooled fast reactor
title_full_unstemmed Preliminary analysis of the post-disassembly expansion phase and structural response under unprotected loss of flow accident in prototype sodium cooled fast reactor
title_sort preliminary analysis of the post-disassembly expansion phase and structural response under unprotected loss of flow accident in prototype sodium cooled fast reactor
publisher The Japan Society of Mechanical Engineers
publishDate 2017
url https://doaj.org/article/029d69babe974376bf8abaf7ec1bda13
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AT kenichimatsuba preliminaryanalysisofthepostdisassemblyexpansionphaseandstructuralresponseunderunprotectedlossofflowaccidentinprototypesodiumcooledfastreactor
AT yoshiharutobita preliminaryanalysisofthepostdisassemblyexpansionphaseandstructuralresponseunderunprotectedlossofflowaccidentinprototypesodiumcooledfastreactor
AT tohrusuzuki preliminaryanalysisofthepostdisassemblyexpansionphaseandstructuralresponseunderunprotectedlossofflowaccidentinprototypesodiumcooledfastreactor
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