Development of failure evaluation method for BWR Lower head in severe accident; - Creep damage evaluation based on thermal-hydraulics and structural analyses -

In existing severe accident codes such as MELCOR and THALES2, rupture of reactor pressure vessel (RPV) by relocated molten core is judged using simple models such as temperature and/or stress criteria. However, it is difficult to assess rupture behavior of the lower head of RPV in boiling-water-type...

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Autores principales:	Jinya KATSUYAMA, Yoshihito YAMAGUCHI, Yoshiyuki NEMOTO, Yoshiyuki KAJI, Hiroyuki YOSHIDA
Formato:	article
Lenguaje:	EN
Publicado:	The Japan Society of Mechanical Engineers 2016
Materias:	fukushima daiichi finite element analysis coupled analysis thermal-hydraulics analysis elastic-plastic-creep analysis creep failure evaluation Mechanical engineering and machinery TJ1-1570
Acceso en línea:	https://doaj.org/article/b70b2755dee14717935b96e45be7c822
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spelling	oai:doaj.org-article:b70b2755dee14717935b96e45be7c8222021-11-26T06:51:30ZDevelopment of failure evaluation method for BWR Lower head in severe accident; - Creep damage evaluation based on thermal-hydraulics and structural analyses -2187-974510.1299/mej.15-00682https://doaj.org/article/b70b2755dee14717935b96e45be7c8222016-03-01T00:00:00Zhttps://www.jstage.jst.go.jp/article/mej/3/3/3_15-00682/_pdf/-char/enhttps://doaj.org/toc/2187-9745In existing severe accident codes such as MELCOR and THALES2, rupture of reactor pressure vessel (RPV) by relocated molten core is judged using simple models such as temperature and/or stress criteria. However, it is difficult to assess rupture behavior of the lower head of RPV in boiling-water-type nuclear power plants due to severe accident like Fukushima Daiichi. One reason is that boiling water reactors (BWRs) have geometrically complicated structure with a lot of penetrations. Another one is that BWR lower head is composed of various types of materials of RPV, weld-overlay cladding, control rod guide tubes, stub tubes, welds, etc. Therefore, we have been developing an analysis method to predict time and location of RPV lower head rupture of BWRs considering creep damage mechanisms based on coupled analysis of three-dimensional thermal-hydraulics (TH) and thermal-elastic-plastic-creep analyses. The detailed three-dimensional model of RPV lower head with control rod guide tubes, stub tubes, and welds are constructed. TH analysis is performed to obtain three-dimensional temperature distribution in relocated debris. Using TH analysis results, structural analysis is carried out to evaluate creep damage distributions using four types of damage criterions of “considere”, strain, Kachanov, and Larson-Miller-parameter (LMP) criteria. Creep damage evaluation based on Kachanov and LMP models is made by using experimentally determined parameters. From comparison of damage criterions, it is shown that failure regions of BWR lower head are only penetrations under simulated conditions, although there is a large difference in failure time.Jinya KATSUYAMAYoshihito YAMAGUCHIYoshiyuki NEMOTOYoshiyuki KAJIHiroyuki YOSHIDAThe Japan Society of Mechanical Engineersarticlefukushima daiichifinite element analysiscoupled analysisthermal-hydraulics analysiselastic-plastic-creep analysiscreep failure evaluationMechanical engineering and machineryTJ1-1570ENMechanical Engineering Journal, Vol 3, Iss 3, Pp 15-00682-15-00682 (2016)
institution	DOAJ
collection	DOAJ
language	EN
topic	fukushima daiichi finite element analysis coupled analysis thermal-hydraulics analysis elastic-plastic-creep analysis creep failure evaluation Mechanical engineering and machinery TJ1-1570
spellingShingle	fukushima daiichi finite element analysis coupled analysis thermal-hydraulics analysis elastic-plastic-creep analysis creep failure evaluation Mechanical engineering and machinery TJ1-1570 Jinya KATSUYAMA Yoshihito YAMAGUCHI Yoshiyuki NEMOTO Yoshiyuki KAJI Hiroyuki YOSHIDA Development of failure evaluation method for BWR Lower head in severe accident; - Creep damage evaluation based on thermal-hydraulics and structural analyses -
description	In existing severe accident codes such as MELCOR and THALES2, rupture of reactor pressure vessel (RPV) by relocated molten core is judged using simple models such as temperature and/or stress criteria. However, it is difficult to assess rupture behavior of the lower head of RPV in boiling-water-type nuclear power plants due to severe accident like Fukushima Daiichi. One reason is that boiling water reactors (BWRs) have geometrically complicated structure with a lot of penetrations. Another one is that BWR lower head is composed of various types of materials of RPV, weld-overlay cladding, control rod guide tubes, stub tubes, welds, etc. Therefore, we have been developing an analysis method to predict time and location of RPV lower head rupture of BWRs considering creep damage mechanisms based on coupled analysis of three-dimensional thermal-hydraulics (TH) and thermal-elastic-plastic-creep analyses. The detailed three-dimensional model of RPV lower head with control rod guide tubes, stub tubes, and welds are constructed. TH analysis is performed to obtain three-dimensional temperature distribution in relocated debris. Using TH analysis results, structural analysis is carried out to evaluate creep damage distributions using four types of damage criterions of “considere”, strain, Kachanov, and Larson-Miller-parameter (LMP) criteria. Creep damage evaluation based on Kachanov and LMP models is made by using experimentally determined parameters. From comparison of damage criterions, it is shown that failure regions of BWR lower head are only penetrations under simulated conditions, although there is a large difference in failure time.
format	article
author	Jinya KATSUYAMA Yoshihito YAMAGUCHI Yoshiyuki NEMOTO Yoshiyuki KAJI Hiroyuki YOSHIDA
author_facet	Jinya KATSUYAMA Yoshihito YAMAGUCHI Yoshiyuki NEMOTO Yoshiyuki KAJI Hiroyuki YOSHIDA
author_sort	Jinya KATSUYAMA
title	Development of failure evaluation method for BWR Lower head in severe accident; - Creep damage evaluation based on thermal-hydraulics and structural analyses -
title_short	Development of failure evaluation method for BWR Lower head in severe accident; - Creep damage evaluation based on thermal-hydraulics and structural analyses -
title_full	Development of failure evaluation method for BWR Lower head in severe accident; - Creep damage evaluation based on thermal-hydraulics and structural analyses -
title_fullStr	Development of failure evaluation method for BWR Lower head in severe accident; - Creep damage evaluation based on thermal-hydraulics and structural analyses -
title_full_unstemmed	Development of failure evaluation method for BWR Lower head in severe accident; - Creep damage evaluation based on thermal-hydraulics and structural analyses -
title_sort	development of failure evaluation method for bwr lower head in severe accident; - creep damage evaluation based on thermal-hydraulics and structural analyses -
publisher	The Japan Society of Mechanical Engineers
publishDate	2016
url	https://doaj.org/article/b70b2755dee14717935b96e45be7c822
work_keys_str_mv	AT jinyakatsuyama developmentoffailureevaluationmethodforbwrlowerheadinsevereaccidentcreepdamageevaluationbasedonthermalhydraulicsandstructuralanalyses AT yoshihitoyamaguchi developmentoffailureevaluationmethodforbwrlowerheadinsevereaccidentcreepdamageevaluationbasedonthermalhydraulicsandstructuralanalyses AT yoshiyukinemoto developmentoffailureevaluationmethodforbwrlowerheadinsevereaccidentcreepdamageevaluationbasedonthermalhydraulicsandstructuralanalyses AT yoshiyukikaji developmentoffailureevaluationmethodforbwrlowerheadinsevereaccidentcreepdamageevaluationbasedonthermalhydraulicsandstructuralanalyses AT hiroyukiyoshida developmentoffailureevaluationmethodforbwrlowerheadinsevereaccidentcreepdamageevaluationbasedonthermalhydraulicsandstructuralanalyses
_version_	1718409740688556032

Development of failure evaluation method for BWR Lower head in severe accident; - Creep damage evaluation based on thermal-hydraulics and structural analyses -

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