SimulationofMCCIwiththeTOLBIAC-ICBcodebasedonthephasesegregationmodelOriginalResearchArticle

Intheeventofasevereaccidentinapressurizedwaterreactor,corium,amixtureofmoltenmaterialsissuedfromthefuel,claddingandstructuralelements,appearsinthereactorcore.Insomecircumstances,coriumislikelytomeltthroughthereactorpressurevesselandspreadovertheconcretebasematofthereactorpit.Moltencoreconcreteinteraction(MCCI)thenoccurs.Themainquestionthathastobeaddressedinthisscenarioiswhetherandwhenthecoriumwillmakeitswaythroughthebasemat.Forsomeyears,CEAisdevelopinganumericalcodenamedTOLBIAC-ICBinordertosimulatemoltencoreconcreteinteractioninreactorcase.ThegeneralapproachusedinthiscodeisbasedonthephasesegregationmodeldevelopedbyCEA.Thesolidphaseissupposedtobelocatedatthecoriumpoolboundariesasasolidcrustcomposedofrefractoryoxides,whereasthecoriumpoolcontainsnosolid.Theinterfacialtemperaturebetweenthecrustandthepoolistheliquidustemperaturecalculatedwiththecompositionofthepool.Theinteractionbetweenthermalhydraulics(massandenergybalances)andphysico-chemistry(liquidustemperature,crustcomposition,chemicalreaction)ismodelledthroughacouplingbetweenTOLBIAC-ICBandtheGEMINIcodeforthedeterminationofthephysico-chemistryvariables.ThemainpurposeofthispaperistopresentthemodellingusedinTOLBIAC-ICBandsomevalidationcalculationsusingthedataofexperimentsavailableintheliterature.