Author/Authors :
B.Clément، نويسنده , , T.Haste، نويسنده , , Fridolin Krausmann، نويسنده , , S.Dickinson، نويسنده , , G.Gyenes، نويسنده , , J.Duspiva، نويسنده , , F.deRosa، نويسنده , , S.Paci، نويسنده , , F.Martin-Fuertes، نويسنده , , W.Scholytssek، نويسنده , , H.-J.Allelein، نويسنده , , S.Güntay، نويسنده , , B.Arien، نويسنده , , S.Marguet، نويسنده , , M.Leskovar، نويسنده , , A.Sartmadjiev، نويسنده ,
Abstract :
TheTHENPHEBISP2-yearthematicnetworkstartedinDecember2001,andwasconcernedwithOECD/CSNIInternationalStandardProblem46,itselfbasedonthePhebusFPT1coredegradation/sourcetermexperiment.Theaimwastoassessthecapabilityofcomputercodestomodelinanintegratedwaythephysicalprocessestakingplaceduringasevereaccidentinapressurisedwaterreactor,fromtheinitialstagesofcoredegradation,thefissionproducttransportthroughtheprimarycircuitandthebehaviourofthereleasedfissionproductsinthecontainment.ISP-46,coordinatedbyIRSN/DRSCadarache,attracted33participatingorganisations,from23countriesandinternationalbodies,whosubmitted47basecasecalculationsand21best-estimatecalculations,using15differentcodes.
Thethermalbehaviourofthefuelbundleandthehydrogenproductionweregenerallywellcaptured,andgoodagreementforthecorefinalstatecouldbeobtainedwithasuitablechoiceofbulkfuelrelocationtemperature,howeverthisisunlikelytoberepresentativeofallplantstudiessosensitivitycalculationsareneededwiththemodellinginitscurrentstate.Totalvolatilefissionproductreleasewassimulated,butitskinetics,andtheoverallmodellingofsemi-volatile,low-volatileandstructuralmaterialrelease(Ag/In/Cd,Sn)needsimprovement.Overallretentioninthecircuitiswellpredicted,butcalculationsunderestimatedepositsintheupperplenumandoverestimatethoseinthesteamgenerator,alsothevolatilityofsomeelementscouldbebetterpredicted.Containmentthermalhydraulicsanddepletionrateofaerosolsarewellcalculated,butwithdifficultiesrelatedtopartitionamongstthedepositionmechanisms.Calculationofiodinechemistryinthecontainmentturnedouttobemoredifficult.Itsqualitystronglydependsofthecalculationofreleaseandtransportintheintegralcodes.Themajordifficultiesarerelatedtotheexistenceofgaseousiodineintheprimarycircuitandtothepredictionoftheamountoforganiciodineinthegasphase.Thispapersummarisestheresultsachievedandtheimplicationsforplantcalculations
