RuptureofspentfuelZircaloycladdingindrystorageduetodelayedhydridecrackingOriginalResearchArticle

DelayedhydridecrackingintheZircaloyalloyhasbeenconsideredasapossibledegradationmechanismofspentnuclearfuelcladdingininterimdrystorage.Somerecentin-corefuelfailuresindicatedthatalongaxialcrackdevelopedinthecladdingwasasecondaryfailurebydelayedhydridecracking.TheaimofthisstudyistodefinetheeffectsofhydridereorientationonthefailureofZircaloycladding.Differenthydrideorientations,theamountofzirconiumhydrideandvariouscrackingtypes,allhavebeenconsideredfortheireffectsonthecrackgrowthandstabilityofthecladding,andhavebeenthoroughlydiscussedinthispaper.Afiniteelementcomputercode,ANSYS,hasbeenusedinconjunctionwiththestrainenergydensitytheory.Insummary,thecrackpropagationwillbeaggravatedifthehydrideorientationisshiftedfromthecircumferentialtotheradialdirection.Foralargercracklength,thezirconiumhydrideplaysanimportantroleinaffectingthecrackgrowthbecausethestrainenergydensityfactorincreasesasthehydrideapproachesthecracktip.Furthermore,whenthermaleffectsareconsidered,acompressivestressexistsattheinnersideofthecladding,whileatensilestressisfoundattheoutersideofcladding,thusresultingincrackpropagationfromtheoutersidetotheinnersideofthecladding.Thesefindingsareinaccordancewithotherexperimentalresultsinrelatedliterature.