Preliminarythermal-hydraulicphenomenainvestigationduringtotalinstantaneousblockageaccidentforCEFROriginalResearchArticle

TheChineseExperimentalFastReactor(CEFR)isunderinstallationandcommissioningrightnow.Itisessentialtoinvestigatecoredisruptiveaccidents(CDAs)fortheevaluationofCEFRʹssafetycharacteristic.Aspart-Ipreliminaryinvestigation,accidentoftotalinstantaneousblockage(TIB)insinglesubassemblyscaleismodeledandanalyzed.Thedegradationscenariohasbeencalculatedbyafluid-dynamicsanalysiscodeforliquid–metalfastreactors(LMFRs).Forfurtherinvestigationofaccidentprocessandinfluencetotheneighboringbundles,sevensubassemblydomainisthensimulatedandcalculatedaspart-IIinvestigation.Totalinstantaneousblockageisassumedtooccurinthecentersubassemblyundernormaloperatingconditionsandconsequencestoneighboringassembliesarestudied.Theresultshowsthatthekeyevents,suchassodiumboiling,cladmelting,fuelparticlesrelocation,hexcanmelt-throughandmeltpropagationintoneighboringsixassembliessymmetricallyareadequatelysimulated.FromcomparisonanddiscussionoftheCEFRʹsresultswiththeSCARABEEtestsandSuperphenix(SPX1)-typereactorsimulation,itisconcludedthatallthekeyeventsappearinthesamesequencewhereasthepropagationislimitedinneighboringsixassemblies.ThediscrepancyisprobablyduetolessfuelinventoryandbettercoolingcapacityinCEFRsubassemblydesign.TIBcalculationshelptogiveabetterunderstandingandpredictionofhypotheticalaccidentscenarioinsubassemblyblockageaccidentsforCEFR.