Title of article
HELIOcodepredictionofhydrogenaccumulationinnon-ventedsteampipelinesOriginalResearchArticle
Author/Authors
VladimirD.Stevanovic، نويسنده , , ZoranV.Stosic، نويسنده , , UweStoll، نويسنده ,
Issue Information
روزنامه با شماره پیاپی سال 2006
Pages
11
From page
1728
To page
1738
Abstract
Thethermal-hydraulicandphysico-chemicalcodeHELIOisdevelopedfornumericalsimulationsandanalysesofradiolyticgases(hydrogenandoxygen)accumulationinnon-ventedsteampipelinesofnuclearpowerplantsystems.TheHELIOcodesimulatesallrelevantprocess,suchasthesteam–radiolyticgasesmixtureconvection,thecondensatedrainage,thebuoyancyforcesinducedbyconcentrationandrelatedgasmixturedensitydifferences,thegasmixtureandcondensatefilminterfacialshear,thesteamcondensationinthepresenceofnon-condensables,thenon-condensablesdiffusion,andtheradiolyticgasesabsorptionanddegassingontheliquidfilmsurface.ThispaperpresentsHELIOcodemodels,numericalsolvingprocedureandthreecasesofresultsofthree-dimensionalradiolyticgasesaccumulation:(a)inanon-ventedsteampipelineoftheResidualHeatRemovalSystemintheHamaokaNuclearPowerPlant,(b)inanon-ventedhorizontalpipeconnectedwithanelbowandaverticalpipe,and(c)inaslightlyinclined,nearlyhorizontalpipe.Theradiolyticgasesaccumulationinthemixturewithsteamisaveryslowandlongdurationtransientthatisinducedbythesteamcondensationduetoheatlossestotheatmosphere.Thecondensateisdrained,whiletheconcentrationofremainingnon-condensableradiolyticgasesincreases;theprocessthatcouldleadtotheformationofacriticalhydrogenandoxygenconcentrationandsubsequentexplosion,asincaseoftheHamaokaplantincident.IncaseoftheHamaokasteampipelinegeometry,presentedresultsshowanaccumulationoftheradiolyticgasesfromtheclosedtopendofthepipeline,aformationoftheconcentrationfrontanditspropagationtowardstheopenend.Inthesecondanalyzedcase,thegasmixturecirculatesintheelbowandhorizontalpipeduetobuoyancyforcesinducedbyconcentrationandrelateddensitydifferences.Thecirculationflowpreventstheformationofradiolyticgasesconcentrationfrontandanaccumulatedradiolyticgasesconcentrationislow.Thethirdcaseshowsthatunderlowerheatlossratesorhigherpipediametersthehydrogen–oxygenaccumulationdoesnotoccurduetothebuoyancydrivencirculationofgasmixture;thecirculationexpelsthegasmixturestreamwithahigherradiolyticgasesconcentrationoutofthepipe.Obtainedresultsclarifymechanismsoftheradiolyticgasesaccumulationandtheyareasupporttotheprescriptionofsafetymeasuresthatshouldbeappliedinordertopreventanaccumulationandeventualexplosion.
Journal title
Nuclear Engineering and Design Eslah
Serial Year
2006
Journal title
Nuclear Engineering and Design Eslah
Record number
941293
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