Title of article
Semi-analyticalmodelingofaPWRlowerheadfailureundersevereaccidentconditionsusinganaxisymetricalshelltheoryOriginalResearchArticle
Author/Authors
V.Koundy، نويسنده , , I.Cormeau، نويسنده ,
Issue Information
روزنامه با شماره پیاپی سال 2005
Pages
9
From page
845
To page
853
Abstract
TheUSNRC/SNLOLHFprogramwascarriedoutwithintheframeworkofanOECDproject.Thisprogramconsistedoffourone-fifthscaleexperimentsofareactorpressurevessel(RPV)lowerheadfailure(LHF)underwellcontrolledinternalpressureandlargethroughwalltemperaturedifferentials;theobjectivesweretocharacterizethemode,timingandsizeofapossiblePWRlowerheadfailureintheeventofacoremeltdownaccident.Theseexperimentsshouldalsoleadtoabetterunderstandingofthemechanicalbehaviorofthereactorvessellowerhead,whichisofimportancebothinsevereaccidentassessmentandthedefinitionofaccidentmitigationstrategies.Awell-characterizedfailureofthelowerheadisofprimeimportancefortheevaluationofthequantityofcorematerialthatcanescapeintothecontainment,sincethisdefinestheinitialconditionsforallex-vesselevents.Alargequantityofescapingcoriummayleadtodirectheatingofthecontainmentorex-vesselsteamexplosion.Theseareimportantissuesduetotheirpotentialtocauseearlycontainmentfailure.Theexperimentsalsoprovidedataformodeldevelopmentandvalidation.Forourpart,asoneoftheprogrampartners,a2Dsemi-analyticalmodelhasbeendevelopedandusedtosimulatetheseexperiments.TheaimofthiseffortistodevelopasimplifiedbutwellpredictingcodethatcanbethenimplementedinEuropeanintegralsevereaccidentcomputercodes(ASTEC,ICARE/CATHARE).Thispaperpresentsthedetailedmathematicalformulationofthissimplifiedmethodwhichisusedtointerprettheexperimentalresults.Theaxi-symmetricshelltheoryunderinternalpressureproposedbyTimoshenkohasbeenutilised.Thesolutiontotheequilibriumequationsispresented,withparticularattentiontotheRabotnovanalyticalformula.Theradiusandthepolarangleofthedeformedstructurehavebeenwrittenasanalyticalexpressionsinordertotakethelargedisplacementsandlargestrainsintoaccountusingourmathematicalformulation.TheNortontypecreeplawandtheKachanovdamagelawhavebeenused.Severalfailurecriteriawereusedinthecalculationsandtheireffectonthenumericalresultsisdiscussed.This2Dsemi-analyticalmodelgivesverysatisfactoryresultswhencompared,withtheexperimentalandnumericalresultsthatwerepresentedrecentlyintheBenchmarkcalculationsbasedonthefirsttestoftheOLHFprogram.Theperformanceofthismodelisalsoillustratedbyitscapacitytoaccuratelysimulatethedeformationofthelowerhead,includingthevariationofwallthickness.
Journal title
Nuclear Engineering and Design Eslah
Serial Year
2005
Journal title
Nuclear Engineering and Design Eslah
Record number
894892
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