Title of article
IodinebehaviourunderLWRaccidentconditions:LessonslearntfromanalysesofthefirsttwoPhebusFPtestsOriginalResearchArticle
Author/Authors
N.Girault، نويسنده , , S.Dickinson، نويسنده , , F.Funke، نويسنده , , A.Auvinen، نويسنده , , L.Herranz، نويسنده , , Fridolin Krausmann، نويسنده ,
Issue Information
روزنامه با شماره پیاپی سال 2006
Pages
16
From page
1293
To page
1308
Abstract
TheInternationalPhebusFissionProductprogramme,initiatedin1988andperformedbytheFrench“InstitutdeRadioprotectionetdeSûretéNucléaire”(IRSN),investigatesthroughaseriesofin-pileintegralexperiments,keyphenomenainvolvedinlightwaterreactor(LWR)severeaccidents.Thetestscoverfuelroddegradationandthebehaviouroffissionproductsreleasedviatheprimarycoolantcircuitintothecontainmentbuilding.
Theresultsofthefirsttwotests,calledFPT0andFPT1,carriedoutunderlowpressure,inasteamrichatmosphereandusingfreshfuelforFPT0andfuelburnedinareactorat23GWdt−1forFPT1,wereimmenselychallenging,especiallywithregardtotheiodineradiochemistry.Someofthemostimportantobservedphenomenawithregardtothechemistryofiodinewereindeedneitherpredictednorpre-calculated,whichclearlyshowstheinterestandtheneedforcarryingoutintegralexperimentstostudythecomplexphenomenagoverningfissionproductbehaviourinaPWRinaccidentconditions.Thethreemostunexpectedresultsintheiodinebehaviourrelatedtoearlydetectionduringfueldegradationofaweakbutsignificantfractionofvolatileiodineinthecontainment,thekeyroleplayedbysilverrapidlybindingiodinetoforminsolubleAgIinthecontainmentsumpandtheimportanceofpaintedsurfacesinthecontainmentatmospherefortheformationofalargequantityofvolatileorganiciodides.
TosupportthePhebustestinterpretationsmall-scaleanalyticalexperimentsandcomputercodeanalyseswerecarriedout.Theformer,helpingtowardsabetterunderstandingofoveralliodinebehaviour,wereusedtodeveloporimprovemodelswhilethelattermainlyaimedatidentifyingrelevantkeyphenomenaandatmodellingweaknesses.Specificeffortsweredevotedtoexploringthepotentialoriginsoftheearly-detectedvolatileiodineinthecontainmentbuilding.Ifaclearexplanationhasnotyetbeenfound,thenon-equilibriumchemicalprocessesfavouredintheprimarycoolantcircuitandtheearlyradiolyticoxidationofiodidesinthecondensedwaterfilmsareatpresentthemostlikelyexplanations.Modelsthatweremodifiedordevelopedandembodiedinthecomputercodesfororganiciodideformation/destructioninthegasphaseandAg–Ireactionsinthesumplead,inagreementwiththePhebusfindingsrespectivelytogreatlyenhancedorganiciodideformationkineticsandlongtermconcentrationinthecontainmentatmosphereononehandand,intheconditionsofPhebusexperiments,tosignificantlylimitedmoleculariodinevolatilisationfromthesumpinsofarassilverwasinexcesscomparedtoiodine,ontheotherhand.Organiciodidesthenquicklygaininimportanceandbecomethepredominantvolatileiodinespeciesatlongterm.
Journal title
Nuclear Engineering and Design Eslah
Serial Year
2006
Journal title
Nuclear Engineering and Design Eslah
Record number
896080
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