Title of article
Accidentmanagementfollowinglossofresidualheatremovalduringmid-loopoperationinaWestinghousetwo-loopPWROriginalResearchArticle
Author/Authors
J.Birchley، نويسنده , , T.J.Haste، نويسنده , , M.Richner، نويسنده ,
Issue Information
روزنامه با شماره پیاپی سال 2008
Pages
9
From page
2173
To page
2181
Abstract
Thepossibilityofanaccidentorcomponentfailureduringmid-loopoperationhasbeenidentifiedinprobabilisticstudiesasamajorcontributortocoremeltfrequencyandsourcetermriskduringshutdownconditions.Thewiderangeofplantstatesencounteredandtheunavailabilityofcertainsafetyfeaturesmakeitdifficulttoguaranteethatsafetysystemsoperationwillalwaysbesufficienttoterminatetheaccidentevolution.InthiscontextanalysesareperformedusingMELCOR1.8.5forlossofresidualheatremoval(RHR)atvarioustimesduringmid-loopoperationofaWestinghousetwo-loopPWR.IntheabsenceofrecoveryofRHRorotheraccidentmanagement(AM)measures,thesequencesnecessarilyleadtoalongtermcoreuncovery,heat-upanddegradation,lossofgeometryandeventualfailureofthereactorpressurevessel(RPV).Theresultsshowanextensivetimewindowbeforeuncoveryandadditionallybeforecoredamage,whichincreaseprogressivelywithincreasingtimeaftershutdownatwhichlossofRHRoccurs.Significantoxidationofthecladdingmayresultinconcentrationsofhydrogensufficientfordeflagration.TheslowevolutionimpliesanopportunityfortheplantoperatorstoinitiateAMmeasuresevenaftercoreuncoveryhasstarted.Theanalysesindicateasubstantialtimewindowduringtheuncoverywithinwhichtheinjectioncanrecoverthecorewithoutdamage.Theupperendofthewindowisdeterminedbythetemperatureatwhichheatfromcladdingoxidationbecomesadominantfactor,markingacriticalpointfortheeffectivenessofthisrecoverymode.Theresultsprovideconfidenceintheinherentrobustnessoftheplantwithrespecttoaccidentsequencesofthistype.
Journal title
Nuclear Engineering and Design Eslah
Serial Year
2008
Journal title
Nuclear Engineering and Design Eslah
Record number
895172
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