ProbabilisticmodelingforfracturemechanicstudiesofreactorvesselswithcharacterizationofuncertaintiesOriginalResearchArticle

Theresearchpresentedinthispaperaddressessomeimportantprobabilisticfracturemechanicsissuesraisedinrecenteffortsforassessingpressurizedthermalshockrisk(PTS)inpressurizedwaterreactors(PWRs).Thecommonobjectivesaddressingtheseissueswereto(1)provideaframeworkincludinguncertaintycharacterizationandtreatmentforPTSstudies;(2)usethescreeningcriteriaforscenarioselectiondevelopedandreportedbytheauthors;(3)developasimplecomputationapproachforPTSanalyses;and(4)supportotherresearchersintheireffortstodeveloptoolsandtechniquesforreactorvesselfailureassessment. ThePTSevaluationconsistsofthreedisciplines:probabilisticriskassessment,thermalhydraulics,andprobabilisticfracturemechanics.Themajorcontributionofthisresearchhasbeentoprovideaframeworkforthefracturemechanicsaspectsofpressurizedthermalshockanalysisincludinguncertaintycharacterizationandtreatment.Theuncertaintyanalysisproposedinthisresearchmakesadistinctionbetweenaleatoryandepistemicuncertaintiesforproperpropagationofuncertainties. Toeasethecomputationalburdenincurredbyintroducingthermalhydraulicsuncertainties,asimpleandreasonablyaccuratefracturemechanicscomputationalapproachthatperformsfracturemechanicscalculationsrapidlyandconservativelyisproposed.TheapproachistestedbydevelopingamathematicalroutineinformofasimpleMathematica™routinecalledMATH-PFM.