Press Release-97-079, NRC Sends Letters to Sierra Nuclear, Three Utilities on Spent Fuel Storage Cask Welding Problems, Press Release-97-079, NRC Sends Letters to Sierra Nuclear, Three Utilities on Spent Fuel Storage Cask Welding Problems

Press Release-97-079, NRC Sends Letters to Sierra Nuclear, Three Utilities on Spent Fuel Storage Cask Welding Problems

ML003709793
Person / Time
Issue date:	05/16/1997
From:	Office of Public Affairs
To:
Category:Press Release
References
Press Release-97-079
Download: ML003709793 (2)

Text

UnitedStatesNuclearRegulatoryCommissionOfficeofPublicAffairsWashington,DC20555Phone301-415-8200Fax301-415-2234 Internet:opa@nrc.govNo.97-079FORIMMEDIATERELEASE (Friday,May16,1997)NRCSENDSLETTERSTOSIERRANUCLEAR,THREEUTILITIESONSPENTFUELSTORAGECASKWELDINGPROBLEMSTheNuclearRegulatoryCommission'sOfficeofNuclearMaterialSafetyandSafeguardshasissuedConfirmatoryAction LetterstoSierraNuclearCorporation,designeroftheVSC-24dry storagecaskforspentnuclearfuel,andthreeutilitiesthatuse thecaskatpowerplants.ThelettersconfirmthatSierraand theutilitieswilltakecertainactionsregardingwelding problemswiththecasks.TheutilitiesandplantswherethecasksareusedareEntergyOperations,Inc.,operatorofArkansasNuclearOnenear Russellville,Arkansas;ConsumersPowerCo.,operatorofthe PalisadesnuclearpowerplantnearSouthHaven,Michigan;and WisconsinElectricPowerCompany,operatorofthePointBeach nuclearpowerplantnearManitowoc,Wisconsin.SierraNuclearholdsanNRCcertificateapprovingtheuseoftheVSC-24.NRCconductsinspectionstodeterminewhetherthe systemisbeingmanufacturedinaccordancewiththeNRC-certified

design.AninspectionconductedtheweekofMarch17atSierraNuclearandtwoofitsfabricationcontractorfacilitiesfocused onproblemspreviouslyfoundinweldsjoiningtheinnercasklid tothecaskwallsinVSC-24unitsatthePalisadesandArkansas plants.Followingthatinspection,problemsarosewhilewelding anotherArkansascask.TheMarchinspectionrevealedthatneitherSierraNuclearnortheutilitylicenseeshadperformedacomprehensiveroot causeanalysisofthefirsttwoweldproblems.Anunderstanding oftherootcauseisessentialtopreventingrecurrencewhen weldingfuturecasks,andassessingthepossibilityofadditional weldproblemsandcracking.OnMay6,NRCheldapublicmeetingwithSierraNucleartodiscussactionstakenandplannedbythecompanyinresponseto theinspectionfindings.Afterthemeeting,theNRCstaff concludedthattherootcauseofthewelddefectshasnotbeenadequatelydetermined.TheNRClettertoSierraNuclearconfirmsthatthecompanywilldeterminetherootcauseofthewelddefects,assessthe potentialfordelayedcrackinginweldsthatattachthetwoouter lidstothecaskwallsinthe19VSC-24caskspresentlyinuse (atArkansas,PalisadesandPointBeach),andevaluate appropriatecorrectiveactionstopreventrecurrenceofweld problems.Aftercompletingtheseactions,thecompanywill submitawrittendescriptionoftheseevaluationstotheNRCby June30.TheNRCletterstothethreeutilitiescurrentlyusingtheVSC-24casksconfirmthat--beforeloadingadditionalVSC-24casks withspentfuel--theywilldeterminethattheirweldingand inspectionpracticesprovidereasonableassurancethatcracking, includingpossibleundetectedordelayedcracking,willnotoccur inthesealweldsbetweenthetwoouterlidsofthecasksystem andthecaskwalls,and,ifnecessary,modifytheirwelding processestoinhibitrecurrenceoftheweldingproblem.After completingthisaction,theutilitieswillsubmittotheNRC,at least14daysbeforeloadinganotherVSC-24caskwithspentfuel, awrittendescriptionofanyproceduralordesignmodifications made,includingatechnicaljustificationforeachmodification.CopiesoftheletterswillbeavailableontheNRCOfficeofPublicAffairshomepageat:http://www.nrc.gov/OPA.