Coriumretentionforhighpowerreactorsbyanin-vesselcorecatcherincombinationwithExternalReactorVesselCoolingOriginalResearchArticle

Iftherewereinadequatecoolingduringareactoraccident,asignificantamountofcorematerialcouldbecomemoltenandrelocatetothelowerheadofthereactorvessel,ashappenedintheThreeMileIslandUnit2(TMI-2)accident.Ifitispossibletoensurethatthevessellowerheadremainsintactsothatrelocatedcorematerialsareretainedwithinthevessel,theenhancedsafetyassociatedwiththeseplantscanreduceconcernsaboutcontainmentfailureandassociatedrisk.Forexample,theenhancedsafetyoftheWestinghouseAdvanced600MWePressurizedWaterReactor(AP600),whichrelieduponExternalReactorVesselCooling(ERVC)forin-vesselretention(IVR),resultedintheUnitedStatesNuclearRegulatoryCommission(USNRC)approvingthedesignwithoutrequiringcertainconventionalfeaturescommontoexistingLightWaterReactors(LWRs).Accordingly,IVRofcoremeltisakeysevereaccidentmanagementstrategyadoptedbysomeoperatingnuclearpowerplantsandproposedforsomeadvancedlightwaterreactors.However,itisnotclearthatcurrently-proposedmethodstoachieveERVCwillprovidesufficientheatremovalforhigherpowerreactors.AUS–KoreanInternationalNuclearEnergyResearchInitiative(INERI)projecthasbeeninitiatedinwhichtheIdahoNationalEngineeringandEnvironmentalLaboratory(INEEL),SeoulNationalUniversity(SNU),PennsylvaniaStateUniversity(PSU),andtheKoreaAtomicEnergyResearchInstitute(KAERI)willdetermineifIVRisfeasibleforreactorsupto1500MWe.Thispapersummarizesresultsfromthefirstyearofthis3-yearproject.