Title of article
Predictionofmoisturemigrationandporepressurebuild-upinconcreteathightemperaturesOriginalResearchArticle
Author/Authors
Y.Ichikawa، نويسنده , , G.L.England، نويسنده ,
Issue Information
روزنامه با شماره پیاپی سال 2004
Pages
15
From page
245
To page
259
Abstract
Predictionofmoisturemigrationandporepressurebuild-upinnon-uniformlyheatedconcreteisimportantforsafeoperationofconcretecontainmentvesselsinnuclearpowerreactorsandforassessingthebehaviouroffire-exposedconcretestructures.(1)Changesinmoisturecontentdistributioninaconcretecontainmentvesselduringlong-termoperationshouldbeinvestigated,sincethedurabilityandradiationshieldingabilityofconcretearestronglyinfluencedbyitsmoisturecontent.(2)Thepressurebuild-upinaconcretecontainmentvesselinapostulatedaccidentshouldbeevaluatedinordertodeterminewhetheraventingsystemisnecessarybetweenlinerandconcretetorelievetheporepressure.(3)Whenconcreteissubjectedtorapidheatingduringafire,theconcretecansufferfromspallingduetopressurebuild-upintheconcretepores.
Thispaperpresentsamathematicalandcomputationalmodelforpredictingchangesintemperature,moisturecontentandporepressureinconcreteatelevatedtemperatures.Apairofdifferentialequationsforone-dimensionalheatandmoisturetransferinconcretearederivedfromtheconservationofenergyandmass,andtakeintoaccountthetemperature-dependentreleaseofgelwaterandchemicallyboundwaterduetodehydration.Theseequationsarenumericallysolvedbythefinitedifferencemethod.Inthenumericalanalysis,thepressure,densityanddynamicviscosityofwaterintheconcreteporesarecalculatedexplicitlyfromasetofformulatedequations.
Thenumericalanalysisresultsarecomparedwithtwodifferentsetsofexperimentaldata:(a)long-term(531days)moisturemigrationtestunderasteady-statetemperatureof200°C,and(b)short-term(114min)pressurebuild-uptestundertransientheating.Theseexperimentswereperformedtoinvestigatethemoisturemigrationandpressurebuild-upintheconcretewallofareactorcontainmentvesselathightemperatures.Theformerexperimentsimulatedtheeffectoflong-termsteady-statelinertemperatureduringnormaloperation,andthelattersimulatedasituationwhereanaccidentresultedinsudden,short-termheatingtoapproximately400°C.
Finally,concretespallingissimulatedbythenumericalanalysis;andtheresultsshowhowthemoisturecontentandporepressuredistributionsinconcreteexposedtofirechangewithtimeandtemperature.Thenumericalanalysiscanpredictthetime,positionandtemperatureatwhichspallingoccurs.
Journal title
Nuclear Engineering and Design Eslah
Serial Year
2004
Journal title
Nuclear Engineering and Design Eslah
Record number
894684
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