ExperimentsatthemixingtestfacilityROCOMforbenchmarkingofCFDcodesOriginalResearchArticle

Abstract Forthevalidationofcomputationalfluiddynamics(CFD)codes,experimentaldataonfluidflowparameterswithhighresolutionintimeandspaceareneeded. RossendorfCoolantMixingModel(ROCOM)isatestfacilityfortheinvestigationofcoolantmixingintheprimarycircuitofpressurizedwaterreactors.ThisfacilityreproducestheprimarycircuitofaGermanKONVOI-typereactor.Allimportantdetailsofthereactorpressurevesselaremodelledatalinearscaleof1:5.Thefacilityischaracterizedbyflexiblepossibilitiesofoperationinawidevarietyofflowregimesandboundaryconditions.Theflowpathofthecoolantfromthecoldlegsthroughthedowncomeruntiltheinletintothecoreisequippedwithhigh-resolutiondetectors,inparticular,wiremeshsensorsinthedowncomerofthevesselwithameshof64×32measurementpositionsandinthecoreinletplanewithonemeasurementpositionfortheentryintoeachfuelassembly,toenablehigh-levelCFDcodevalidation.TwodifferenttypesofexperimentsattheROCOMtestfacilityhavebeenproposedforthispurpose.Thefirstproposalconcernsthetransportofaslugofhot,under-boratedcondensate,whichhasformedinthecoldlegafterasmallbreakLOCA,towardsthereactorcoreundernaturalcirculation.Thepropagationoftheemergencycorecoolingwaterinthetestfacilityundernaturalcirculationorevenstagnantflowconditionsshouldbeinvestigatedinthesecondtypeofexperiment.ThemeasureddatacancontributesignificantlytothevalidationofCFDcodesforcomplexmixingprocesseswithhighrelevancefornuclearsafety.