Title of article :
BorondilutiontransientsduringnaturalcirculationflowinPWR—ExperimentsandCFDsimulationsOriginalResearchArticle
Author/Authors :
ThomasH?hne، نويسنده , , S?renKliem، نويسنده , , UlrichRohde، نويسنده , , Frank-PeterWeiss، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2008
Abstract :
Coolantmixinginthecoldleg,downcomerandthelowerplenumofpressurizedwaterreactorsisanimportantphenomenonmitigatingthereactivityinsertionintothecore.Therefore,mixingofthede-boratedslugswiththeambientcoolantinthereactorpressurevesselwasinvestigatedatthefourloops1:5scaledRossendorfcoolantmixingmodel(ROCOM)mixingtestfacility.Inparticularthermalhydraulicsanalyseshaveshown,thatweaklyboratedcondensatecanaccumulateinthepumploopsealofthoseloops,whichdonotreceiveasafetyinjection.Afterrefillingoftheprimarycircuit,naturalcirculationinthestagnantloopscanre-establishsimultaneouslyandthede-boratedslugsareshiftedtowardsthereactorpressurevessel(RPV).
IntheROCOMexperiments,thelengthoftheflowrampandtheinitialdensitydifferencebetweentheslugsandtheambientcoolantwasvaried.Fromthetestmatrixexperimentswith0resp.2%densitydifferencebetweenthede-boratedslugsandtheambientcoolantwereusedtovalidatetheCFDsoftwareANSYSCFX.TomodeltheeffectsofturbulenceonthemeanflowahigherorderReynoldsstressturbulencemodelwasemployedandameshconsistingof6.4millionhybridelementswasutilized.OnlytheexperimentsandCFDcalculationswithmodeleddensitydifferencesshowstratificationinthedowncomer.Dependingonthedegreeofdensitydifferencesthelessdenseslugsflowaroundthecorebarrelatthetopofthedowncomer.Attheoppositeside,thelowerboratedcoolantisentrainedbythecoldersafetyinjectionwaterandtransportedtothecore.ThevalidationprovesthatANSYSCFXisabletosimulateappropriatelytheflowfieldandmixingeffectsofcoolantwithdifferentdensities.
Journal title :
Nuclear Engineering and Design Eslah
Journal title :
Nuclear Engineering and Design Eslah
