OnsomesalientunresolvedissuesinsevereaccidentsforadvancedlightwaterreactorsOriginalResearchArticle

Someoftheoutstandingissuesofthesevereaccidentareevaluatedfromthesynthesisoftheresultsfromtheresearchprogramsofthesimulationofnaturallyarrestedthermalattackinthevessel(SONATA),testforrealcoriuminteractionwithwater(TROI),andthetestfortheperformanceofaquenchingscreenforahydrogenburn. Thestrategyoftheinvesselretention(IVR)byanexternalreactorvesselcooling(ERVC)isevaluatedfortheKoreaStandardNuclearPowerPlant(KSNP)andAdvancedPowerReactor-1400(APR-1400).ThefavorableandadverseeffectsoftheproposedstrategyandtheuncertaintiesoftherelevantphenomenaincludingthegapcoolingandheatremovalcapabilityoftheEVRCarediscussed.Itisshownthatthethermalmarginforthefailureofthereactorvesselischallengedforthesereactors.TheobservationoftheenergeticspontaneoussteamexplosionsintheTROIsuggeststhatpropermeasuresshouldbetakentoavoidand/orlessentheriskofanin-vesselorex-vesselsteamexplosion,whenweemployanex-vesselcoolingstrategyand/oraninvesselinjectionstrategy. Toaddresstheissuethatmultipleburnsinducedbythehydrogenignitercanposeathreattothesafetyequipment,theuseofaquenchingscreenissuggested.Theresultsofthelaboratoryscaleexperimentsfortheperformanceofthequenchingscreenindicatedthefeasibilityofusingaquenchingscreentoprotecttheessentialequipmentbystoppingtheflamepropagation