ML19015A118
| ML19015A118 | |
| Person / Time | |
|---|---|
| Site: | Holtec |
| Issue date: | 01/11/2019 |
| From: | Anton S, Bullard C, Manzione K, Singh K, Tindal R Holtec |
| To: | Michael Layton Division of Spent Fuel Management |
| Love E | |
| References | |
| Document ID: 5014862 IR 2018201 | |
| Download: ML19015A118 (37) | |
Text
www.holtec.com Holtecs Input to the PEC Proceedings on NRCs Inspection Report
- 07201014/2018-201 Presented by:
Dr. Kris Singh, Chief Technology Officer Dr. Stefan Anton, Vice President-Engineering Kim Manzione, Licensing Manager Robert Tindal, Senior Director, NPD Chuck Bullard, Director, Engineering Mechanics USNRC, White Flint, MD; January 9, 2019 Revised Version Issued to the NRC: January 11, 2019 ATTACHMENT 1 TO HOLTEC LETTER 5014862 1 of 37
www.holtec.comlPage2 Agenda PurposeofthePresentation SummaryofApparentViolations BasketShimDetails SummaryofWhatHappened MPCStatusandInspectionResults SafetyEvaluationoftheMPCsContainingSSOs CorrectiveActions Summary ATTACHMENT 1 TO HOLTEC LETTER 5014862 2 of 37
www.holtec.comlPage3 Purpose of this Presentation Toprovideadditionalinformationwhichshows:
ThattheentirepopulationofSSOsplaysno roleinthesafetyfunctionof anyoftheMPCsloadedacrosstheCountry.
Stateddifferently,theloadedMPCswouldfulfilltheirintendedfunction withoutexceedinganyregulatorylimitsunderallapplicableconditionsof storageandtransporteveniftheyhadnoSSOs.
BecausetheSSOsplaynoroleinthesafetyperformanceoftheloaded MPCs,theycanbecorrectlycharacterizedasaNotImportanttoSafety (NITS)itemintheBasketShimAssembly.
Thus,whileweacceptthecitedviolations,theirlackofsafetysignificance ismanifestlyevident.Perhaps,theviolationsshouldbetermedminor.
That,learningfromthisepisode,Holtechasperformedastemtosternre appraisalofitsprocessesandoperatingproceduresandmadenumerous systemicimprovementstopreventdamagetoSSCsduringhandlingin manufacturingandtransporttothesiteandothersimilaractivitieswhich heretoforehavebeenoutsidethescopeofthenormalsafetyanalyses.
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www.holtec.comlPage4 Additional Purpose of this Presentation Provideadditionalfactsandinsightstoclarifyandfurtherinform NRCsfindingssummarizedintheinspectionreport.
ToprovideinformationonthesafetyanalysesofaloadedMPCunder thehypotheticalassumptionthatnoSSOwasinstalled:
Thermalanalysisdemonstratesallregulatorylimitsaremet Structuralanalysesdemonstratethattheintegrityofthestoredfueland theFuelBasketremainsunchangedbythepresenceorabsenceofSSOs.
Provideasummaryofthenumerousimprovements,afterthe discoveryofadamagedSSO,madeintheconcepttocommissioning lifecycleofCompanysSSCssothatallconceivableavenuesforfuture failureareblocked.
Theviolationsoccurredbecauseofinadequateconsiderationof manufacturingchallengesinthedesignandinadequatefocuson preventinghumanperformanceerrorduringmanufacturing.
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www.holtec.comlPage5 Two Apparent Violations Cited by the NRC Bothpertaintothebasketshimstandoffs ApparentViolationA Holtecfailedtoestablishadequatedesigncontrol measuresaspartoftheselectionandreviewof suitabilityofapplicationofalternatefourinchshim standoffpins ApparentViolationB Holtecfailedtoperformawrittenevaluationto demonstratethatadesignchangeformultipurpose canisterstainlesssteelstandoffpindidnotrequireaCoC Amendment.
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www.holtec.comlPage6 Basket Shims BasketShimAssembliesoccupythecircumferentialspace betweentheBasketandtheMPCShell DiscreteBasketShimAssemblies surroundtheperipheryof theFuelBasketasshownintheillustrationbelowforMPC37 ATTACHMENT 1 TO HOLTEC LETTER 5014862 6 of 37
www.holtec.comlPage7 What are the SSOs?
What is Their Performance Mission?
TheBasketShimAssembly consistsofshimstandoffs(SSOs) made ofstainlesssteelendthreadedbars,typicallythreeinnumber, fastenedtothebottomoftheBasketShim.
TheSSOsweredesignedtoimprovefabricabilityandevaluated underthe72.48processandtoboostthenativeheatrejection capacityoftheMPCswiththeintenttoseekahigherheatload ratingthroughafutureLAR TheSSOs,shownbelow,increasetheopenheliumflowareainthe MPCsdowncomerspacewhichincreasestherateofheatrejection ATTACHMENT 1 TO HOLTEC LETTER 5014862 7 of 37
www.holtec.comlPage8 SSOs are a Part of the Basket Shim Assembly MPCType NumberofBasketShim ColumnsperMPC TotalNumberof SSOsperMPC MPC37(PWR) 32 88 MPC68M(BWR) 28 76 TheSSOsconsistofmultiplestainlesssteelbarstappedinto thebottomfaceofeachshimcolumntoelevatethemabove theMPCBaseplatetofurtherpromotenaturalconvectionof heliuminsidetheMPC EachMPCtypehasmultipleBasketShimAssemblies,and eachShimhasmultipleSSOs(forredundancy).
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www.holtec.comlPage9 What Happened?
TheSSOswereintroducedviatheECOand72.48processwhich involvedperformingqualifyingsafetyanalyses;theanalysesshowed acceptablesafetymargins.
DuringamanufacturinginvolvingrepeatedrollingtheMPCshell,a smallnumberoftheSSOswerebent,afewevenbrokeoff.The damagetotheSSOsremainedundetecteduntiltheMPCssite inspectionoccurred.
TheincidenceofSSOdamagecorrelateswellwiththeextentofrolling (PeenedMPCs(usedatSONGSonly)exhibitedproportionallygreater SSOdamageratethantheunpeenedones).
TheSSOs,proventoberobustunderdesignbasisloadingsfortheMPCs (whicharediametrical),provedvulnerabletodamageunder circumferentialforcesappliedtothemduringrollingoperations.Afew instancesofobservedbendingoftheSSOsisalsotracedtotheerrorin theirinstallationprocessintheshop.
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www.holtec.comlPage10 Why is the Basket Shim Assembly Classified as an ITS Class C Part?
TheBasketShimAssemblyservestopositiontheFuel BasketinsidetheMPC;itssafetyfunctionisrather minor;viz.:
Itplaysnoroleinreactivitycontrol(criticalitysafety).
Itscontributiontoradiationblockage(shielding)isnegligible.
Itsassistanceinheatrejectionisratherminor(increased conductionbytheshimsmetalmassisoffsetbythe reductioninheattransportbythethermosiphonaction).
InterposedbetweentheMPCShellandtheFuelBasket,it servestoprovideaconformalcontactinterfacewithboth.
TheBasketShimAssemblyisITSCbecauseitplaysno safetyroleinpreventingcriticalityoraradiationrelease event.
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www.holtec.comlPage11 The SSOs in the LOADED MPCs merit being classified as NITS EverySSOforaBasketShimissecuredtoitthrougha threadedconnection.MultipleSSOssupporteach BasketShim.SSOsaredeterminedtohavenosafety impact ontheperformanceoftheMPCsinwhichthey aredeployed,because:
Theydontprovideanymeaningfulradiationshieldingor criticalitycontrol Asdiscussedlater,theresultsoftheFSARcompliantthermal andseismicanalysesontheloadedMPCsprovidedefinitive evidencethattheSSOslackasafetyfunction Inshort,everyloadedMPCmeetstheentiresetof regulatorysafetycriteriaifallofitsSSOswereabsent altogether ATTACHMENT 1 TO HOLTEC LETTER 5014862 11 of 37
www.holtec.comlPage12 Events Following the Discovery of a Broken SSO in an MPC by Holtecs Site Services Team at SONGS ByYearEnd2017-TheintroductionoftheSSOdesignto MPC37andMPC68MthroughEngineeringChangeOrder (ECO)completedandprocessedunder72.48(usingfull evaluation)
February2018-DuringSiteInspectionofMPCdeliveredto SONGS,abrokenSSOwasdiscoveredinsideMPC37byHoltec personnel March2018 Holtecaskedallclientstoperformfocusedinspectionofevery SSObearingMPCtoensurethatallSSOsareintactpriorto loadingthecanister HoltecmadeNRCheadquartersawareoftheSSOissue,provided regularupdatesandcopiesofallsafetyevaluations,andanswered questionsfromNRCstaff.
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www.holtec.comlPage13 Events Following the Discovery of a Broken SSO in an MPC by Holtecs Site Services Team at SONGS (contd)
ARootCauseEvaluation(RCE)wasinstitutedimmediatelywhich includedfactoryandsiteinspectionsanddatacollection, establishingthestatisticalprobabilityofSSOfailureduringthe manufacturingevolutions,safetyanalysestoassessthe consequenceofassumingaboundingassumptionoffailedSSOs, andacomprehensivereappraisaloftheproceduresand practices.Numerousareasofimprovementwereidentified.
AdetailedRCEreportcontainingtheselfidentifiedweaknesses indesignprocesswaspresentedtothevisitingNRCinspection teaminMay2018.
Additionalcorrectiveactions(guidedbyNRCIN9628)defined inpursuitofoperationalexcellence,subsequenttoNRCsvisit, havebeenfullyimplementedacrosstheCompanysdrystorage program.
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www.holtec.comlPage14 Statistics on the SSO-Equipped MPCs OnlyMPC37andMPC68Mmodelswereaffected.
AtthetimeoftheselfidentifiedissuewiththebrokenSSOs, 121MPCswereequippedwithSSOs;thetablebelowshows theirstatusinthreediscretecategories:1.Loaded 2. At HoltecsFabricationFacility; and3.DeliveredtoSitesbutnot loaded.
MPCType Loaded AtHoltecs FabricationFacility Deliveredbutnot Loaded MPC68M(BWR) 22 9
28 MPC37(PWR) 4 26 32 Total 26 35 60 ATTACHMENT 1 TO HOLTEC LETTER 5014862 14 of 37
www.holtec.comlPage15 SSO Inspection Census Over50%ofallSSOs(4,200)werevisuallyinspectedandtheir conditiondocumented(therestinspectedandreplacedas neededbutnotdocumented):
0.12%foundbroken;everybrokenSSOwasintheMPCsthatwere peened(SONGSspecific) 1.22%foundtohaveaslightbend;foundinbothpeenedandun peenedMPCs.
Conclusionsbasedonasfoundconditions:
NoneoftheBasketShimshadsufferedfailureofallofitsSSOs ThepercentageofbrokenSSOsisaverysmallfractionofthe redundancybuiltinthedesign(outofthreeSSOsineachshim,one SSOisredundant)
Furthermore,theevaluationofthepresenceofbrokenSSOsin theMPCindicatedthatthefailuredoesnothaveanysafety impactwhatsoever.
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www.holtec.comlPage16 Safety Evaluation of the MPCs Containing SSOs TheImmediateOperabilityReviewconcludedthatall26loaded systemsweresafeandwouldcontinuetorendertheirintended functionwithoutexceedinganyregulatorylimitsunderallapplicable conditionsofstorageandtransport.
Thethermalsafetyevaluationsfortheimmediateoperabilityreview werebasedontheMPCsasloadedheatloadsundertheoverarching assumptionthateverySSOhasfailedandbecomeinoperative.
SeismicAnalysesusingaboundingearthquakethatenvelopedthe DBEoftheplantswhichwereexecutingloadingsshowedthatevenif onlyoneSSOremainedfunctional ineachshimassembly,thesystem willsuccessfullywithstandtheseismicevent.(TheSSOfailuredoes notimpactthestructuralperformanceoftheMPCwhatsoever)
Assuredbytheinspectionresults,andHoltecssafetyanalyses,all plantsexceptSONGS(whoseDBEexceedsthebounding earthquake)resumedloading.
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www.holtec.comlPage17 SONGS MPCs FourloadedMPCsatSONGSwerereconfirmedtomeet allapplicableregulatorycriteriaforonsitestorageand transportundertheboundingassumptionthatoneSSO hasbeendamagedineveryBasketShim(whichvastly exceedstheobservedrateoffailure).
ThenotyetloadedSSObearingMPCsforSONGS, subjecttotheMostSevereEarthquake,werereturned tothemanufacturingplantandmodifiedtoreplacethe SSOs,eventhoughafocusedinspectionandsurgical SSOreplacementswouldhavesufficed.
Atpresent,alloftheMPCsreadyforloadingatSONGS havenoSSOs ATTACHMENT 1 TO HOLTEC LETTER 5014862 17 of 37
www.holtec.comlPage18 Supplemental Seismic Analysis to answer NRC Inspection Teams query AttherequestoftheNRCinspectionteam,a supplementalseismicanalysiswasperformedwitha boundingRegGuide1.60DBE(1.0gintwohorizontal and0.75gintheverticaldirection)andassumingonly twooperativeSSOs(onehasfailed)supportingeach shimassemblyandthattheywerebothbent.
ThisanalysisshowedthattheMPCwillcontinuetomeet allapplicableregulatorycriteria Insummary,byMay2018,theintegrityofSSOequipped MPCshadbeenestablishedbyanalysisofvarious scenariosrequestedbytheHoltecUserGroupmembers andtheNRC.
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www.holtec.comlPage19 Quantifying the Effect of Assumed SSO Failure on the Thermal Safety Performance of Affected MPC Models Thermalanalyseswereperformedunderthenoncredible, conservativeassumptionthateverySSOhasvanished(non mechanistically)causingeveryBasketShimtodropdownand blockthedowncomertobottomplenumflow.
Thethermalmodelusedemulatesthelicensingbasismodel documentedinthesystemFSAR.
MPC68MinHISTORM100 TheabsenceoftheSSOsdoesnotimpairtheabilityoftheMPCto meettheregulatorylimitunderthefulllicenseddesignbasisheat loadof36.9kW Regulatorylimitsonthepeakcladdingtemperature(PCT)are satisfiedwithrobustmargins.Additionally,theMPCcavitypressure remainsbelowitsdesignlimitsetforthintheFSAR.
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www.holtec.comlPage20 Quantifying the Effect of Assumed SSO Failure on the Thermal Safety Performance of Affected MPC Models (Contd)
MPC37inHISTORMUMAX Regulatorylimitsonthepeakcladdingtemperature (PCT)aresatisfiedwithrobustmarginsforcanistertotal decayheatof37.6kW(HoltecReportHI2188123).
MPCheatloadadoptedforsafetyevaluationsishigher thanthatallowedintheHISTORMUMAXCoC(37.06 kW,AppendixB,Table2.31)
Computedmarginstothelimitaregreaterthanthosein theapprovedFSAR MPCcavitypressureremainsbelowFSARdesignlimit.
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www.holtec.comlPage21 Summary of Thermal Safety Analysis of MPCs with Failed SSOs EventhoughtheinspectionoftheSSOsdidnotindicateeven onebasketshimtohavedroppeddowntothebaseplate becauseoffailedSSOssupportingit,thethermalanalysiswas carriedoutassumingthateverySSOineveryshim hasfailed causingeveryshimtodropdowntothebaseplate,essentially blockingtheflowfromthedowncomertotheinletplenum.
EvenunderthiscounterfactualassumptionofeverySSOfailed, thepeakfuelcladdingtemperatureundertheCoClimitedheat loadremainsbelowtheISG11Rev3limitforMPC68MinHI STORM100andMPC37inHISTORMUMAX Insummary,theSSOsareirrelevanttotheregulatorythermal complianceoftheMPCsinHISTORM100andHISTORMUMAX.
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www.holtec.comlPage22 SSOs Serve No Role in Structural Compliance of the MPCs TheSSOsdonotcontributetothestructuralstrengthof theMPCinanymannerwhatsoever.Theirsolefunction istoenhancetheMPCsheatrejectionrate.
Asobservedinthepreceding,theMPCsmeetthe permissibleheatloadassumingthatnoSSOispresent.
Therefore,theSSOsareentirelysuperfluousforthe safetycomplianceoftheloadedMPCs.
Tocompletethetechnicalevaluations,severalseismic analyseswereneverthelessperformedtoexplorethe MPCsstructuralperformancewithpartiallydamaged populationofSSOs,reportedonthenextslide.
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www.holtec.comlPage23 Structural Evaluation of the SSOs under Seismic loadings Bydesign,theSSOscontributenostructuralstrengthtotheMPCortheFuel Basket.Theseismicanalysis,therefore,wasdevotedtocheckingthestructural integrityoftheSSOsunderassumedSSOfailures.
SeismicanalysisoftheMPCsassumingtwooutofthreeSSOsareunavailable forsupportingeveryshimintheMPCshowedthattheMPCwillwithstanda boundingReg.Guide1.60earthquakepeggedto0.35gintwohorizontal directionsand0.3gverticaldirection(whichboundedtheDBEofeveryactively loadingUSsite)withoutfailureoftheremainingSSOs.
EvenSCEsMostSevereEarthquake(MSE)(Reg.Guide1.60spectrawith unprecedentedZPAsof1.5gineachofthetwoorthogonalhorizontaland1.0gin theverticaldirection)doesnotprecipitateSSOfailureiftheshimissupportedby onlytwo(outofthree)SSOs.
Separately,analysisoftheSSOsduringthehypotheticalcaskdropspursuantto 10CFR71regulationsalsodemonstratedthattheSSOsremainstructurally intactandfullyfunctional
==
Conclusion:==
NoMPCequippedwithSSOsneededtobemodifiedtomeetanyhosts sitesdesignbasisseismicloads.
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www.holtec.comlPage24 Risk Informed Remedial Measures 16additionalMPCswereloadedafteracomprehensive inspectiontoconfirmthatnoSSOwasdamaged.
AllloadedMPCsfullysatisfytheirrespectiveCoC requirement.
TablebelowliststhetotalcountofMPCsbearingSSOs loadedintheindustry.
MPC NumberLoaded priortoDiscovery NumberLoadedafterCompleting FocusedSSOInspections MPC68M 22 16 MPC37 4
0 ATTACHMENT 1 TO HOLTEC LETTER 5014862 24 of 37
www.holtec.comlPage25 Assay of Apparent Violation A ViolationAcitation,Holtecfailedtoestablishadequatedesigncontrol measuresaspartoftheselectionandreviewofsuitabilityofapplication ofalternatefourinchShimStandoffpins.
RootCause Determinedtobeadeficiencyinthedesignchangeprocesswhichdidnot ensuremanufacturingoperationswereconsideredandevaluated.
Holtecsinput:
Holtecdidperformafullevaluationunder72.48priortoadoptingtheSSOs.The companydidonlyascreening(notafullevaluation)afterdamagetotheSSOswas reported.Holtecacceptsthespirit,ifnottheletteroftheviolationcitedabovewhich appliestoof72.146(a)(designcontrol).Holtecsubmitsthat,forreasonsexplainedin theforegoing,thisshouldbeconsideredaminorviolation.
Thelifecycleofnewdesignimplementation(fromdesigntomanufacturingtoonsite implementation)hasthreemajorbarrierswhichare:
DesignReviewProcess FactoryAcceptanceTests/Examinations(FATE)
SiteAcceptanceTests/Examinations(SATE)
Whilethefirsttwobarriersfailed,thethird(SATE)didnot:TheSSOfailurewasdetected duringtheSATEprocessbyHoltecpersonnel.
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www.holtec.comlPage26 Summary of Immediate Corrective Actions Whiletheoperatingproceduresandpracticessucceededin flaggingtheSSOanomalyindicatingthattheQAprogram workedasawhole,theRCEindicatedapressingneedto implementdefinitivecorrectivemeasurestopreclude recurrence.Thefollowingactivitieswerecompletedasapart ofthecorrectiveaction:
Performedsafetyanalysis(thermalandstructural)ofloadedunits toensuretheirsafety Completedallapplicableanalysispackagesforarchivalreference Inspectedallnonloadedunitsandidentifiednecessaryactionson casebycasebasis ReplacedSSOswithmonolithicshimdesigninallapplicableMPCs licensingandfabricationdrawings,reconcileallanalysispackages withthemodifieddesign.
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www.holtec.comlPage27 Strategy to Preclude Recurrence Toprecluderecurrence,theentireedificeoftheproductdesign development,manufacturing,andsiteimplementationprocess(not justDesignChangecontrol)hasbeensubjectedtoacrucialappraisal, whichmeansleveragingthelargebodyofConditionReports(CRs),
NonconformanceReports(NCRs),andFieldConditionReports(FCRs) accumulatedoverthepast32yearsofnuclearQAoperationsatthe Companytoimprovetheoperatingprocessesacrosstheboard.
Usingthewisdomgainedfrompastoperationsaswellasfreshthinking fromtheCompanysthoughtleadersandconsultants,thedesign developmentprocedureswereupgradedtoincludeindepth considerationofmanufacturingandsiteoperations.
Separatethedesigndevelopers(RedTeam)fromthedesigncritics (BlueTeam).Includemanufacturingandsiteservicesexpertsineach.
Emphasizecrossdisciplinetrainingandsolicitfeedbackfrompeoplein thetrenches ATTACHMENT 1 TO HOLTEC LETTER 5014862 27 of 37
www.holtec.comlPage28 Major Actions Complete to Prevent Recurrence UpgradedtheCompanysdesigndevelopmentproceduretoincludeinitial CTOapprovalofconceptualdesign,inprocesspeerreviewsbyredteam, andfinalcritiquebyablueteam ofpreviouslyuninvolvedindependent experts.
Strengthenedtheinitialdesignassessment,EngineeringChangeOrder (ECO)anddrawingreviewquestionnairestoprobeadequacyofthedesign embodimenttowithstandfabricationoperations.
Drawingonthelessonslearneddatabase,developednewquestionnaires toquerythepotentialofnewissuesthatmayariseduringsite implementation.
Developaformalprotocoltoquantifyrisksassociatedwithdesignor processchanges.
UpgradeOJToftechnicalpersonneltoincludetraininginmanufacturing andsiteoperationprocedures EmbedmanufacturingandsiteservicesexpertsintheRedTeam to facilitatediscussionofmanufacturingsubtletiesandpracticalchallengesin siteimplementation.
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www.holtec.comlPage29 Assay of Apparent Violation B ApparentViolationB Holtecfailedtoperformawrittenevaluationtodemonstrate thatadesignchangeformultipurposecanisterstainlesssteel standoffpindidnotrequireaCoCAmendment.
Specifically,forthe72.48saddressingthesitediscoveries, ScreeningswereperformedinsteadofaFullEvaluation Holtecsinput Asstatedearlier,Holtecacceptstheviolationof72.48(d)(1)(design control)inthecontextoffull72.48evaluationofthefielddataon SSOdamage(nottheoriginaldesignchange);however,wesubmit that,forthereasonsdiscussedinthecontextofViolationA,this shouldbeconsideredaminorviolation.
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www.holtec.comlPage30 Corrective Actions and Actions to Prevent Recurrence for Apparent Violation B Upgraded72.48s#1319and#1321(bothareon evaluatingtheeffectoffielddataontheSSOs)to fullevaluations(beforetheywerescreenings).The priorsafetyconclusionsremainunchanged.
Remedialtrainingonthe72.48process implementationprovidedtopersonnel.Also reinforcedexpectationtoerronthesideof conservatismwhendeterminingwhethera72.48 evaluationisneeded(versusscreeningonly).
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www.holtec.comlPage31 Assessment of the Safety Significance of Apparent Violation B ThestatedviolationisfoundtohavenoSafety Significance 72.48fullevaluationconfirmedtheconclusionreached bythepriorscreening.
Technicaljustificationremainedunchanged.
Administrativechangetolicensingpaperworkonly.
Thiswasanisolatedincident,sinceareviewofHoltecs past72.48sgoingbackthreeyearsidentifiednoother suchcase.
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www.holtec.comlPage32 Summary Aswehavediscussedindetail,ouranalysisshowsthat,assuming allSSOsfailandbecomeinoperative,theloadedMPCsfulfilltheir intendedfunctionwithoutexceedinganyregulatorylimitsunder allapplicableconditionsofstorageandtransport.
Hence,theSSOsplaynoroleinthesafetyperformanceofthe loadedMPCsandcanbecorrectlycharacterizedasaNot ImportanttoSafety(NITS)itemintheBasketShimAssembly.
Therefore,whileweaccepttheviolationswebelievetheyentailed minorsafetysignificance.
Topreventrecurrence,Holtechasperformedastemtosternre appraisalofitsprocessesandoperatingproceduresandmade numerousimprovementstopreventdamagetoequipmentduring handlinginmanufacturingandtransporttothesiteandother similaractivitiesoutsidethescopeofthenormalsafetyanalyses.
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www.holtec.comlPage33 Summary (Contd)
NRCEnforcementManualspecifiesthefollowing conditionsunderwhichNRCwillmostlikelynot considerescalatedenforcementactions.Theyare:1) safetysignificanceoftheissuebeingminor;2)issueis self identifiedbythelicenseeandpromptlyplacedin thelicenseesCorrectiveActionProgram;3)licensee promptlycompletesRootCauseAnalysisReport;4) promptlycompletesallrequiredcorrectiveactions;and 5)issuewasnotcausedbyanywillfulactions.
Asthispresentationindicates,wefullymeeteveryone oftheabovecriteriaintheNRCsEnforcementManual.
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www.holtec.comlPage34 Digging Deeper into the Root Cause and Devising Remedial Measures OurassessmentofthesuperveningrootcausebehindtheSSOmalfunction isapervasivelackofknowledgeintheindustryregardingthemany collateraleffectsofmanufacturingprocessonthehardwaresperformance.
InNRCsregulatoryliterature,NEIsguidance,andHoltecsowninternal controls,theattentionpaidtothecomplexroleplayedbythefabrication processeshasbeeninadequate.Thiscallsforafundamentalchangeinthe waydesign/changedevelopmentworkisconducted.
Thefirststepiseducatingboththedesigndevelopersandthemanufacturing personnelintothefocusedsymbioticrelationshipbetweentheirdisciplines.
(Towardsthisend,apersonneltrainingprogramisbeingimplementedatHoltec)
Next,expandthedesignchangeexecutionand72.48screeningprocessesto integrateconsiderationsofdesign,manufacturing,andsiteoperationsandtheir effectoneachother(AmajorupgradeoftheECOand72.48questionnaireshas beencarriedout)
Third,increasetechnicalpersonnelsexposuretomanufacturing.(Establishingthe manufacturingplantadjacenttotheengineeringofficesisakeystepinthis direction).
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www.holtec.comlPage35 Synopsis of Lessons Learned from the SSO Episode Makeanintensivecorporateefforttoincludenuancesof manufacturingandsiteservicesintheSSCsdesigndevelopment effort.
IntensifytrainingtheCompanypersonnelonthesymbiotic relationshipbetweendesignandmanufacturing.Personnel mustbegivedeepimmersioninreallifemanufacturing.
BroadentheECO/72.48processestoincludeindepth considerationofmanufacturingandsiteoperations.
Increaseinprocessreviewandcritiqueofevolvingdesign decisions(CTO,RedTeam,andBlueTeamreviews).
Whenindoubt,doafull72.48evaluation.
Continuouslyupgradetheproceduresusinglessonslearnedfrom continuingoperations-complacencyistheenemyofquality.
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www.holtec.comlPage36 Concluding Remarks AllloadedcanisterswithSSOsfullymeettheirCoCspecifications.
TheSSOsintheloadedMPCscanbecharacterizedasNITS.Theirsole functionistoaddmarginbyenhancingtheMPCsheatrejectionrate.
HOLTECacceptstheviolationof72.146(a)(designcontrol)butourassessment showsthatthesafetysignificanceisminor.
HOLTECacceptstheviolationof72.48(d)(1)(recordsofchanges)withregardto evaluationoffieldconditions(butnotthechangetotheSSOs,whichdidreceivea fullevaluation).Ourfull72.48evaluations,performedsubsequently,didnot screentoahighersignificance.
Holtechasrevampedandupgradedtheentirearrayofprocessesandprocedures includingthosepertainingtoprojectplanning,designcontrol,72.48screening&
evaluation,fabricabilityreview,siteoperationprocedures,personneltraining regimen,andriskinformeddecisionmaking.
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www.holtec.comlPage37 Concluding Remarks (Contd)
InformationtoClarifyNRCInspectionReportDiscussionofViolationA. statesthatSSOssupporttheFuelBasket.However,the designoftheSSOsissuchthattheydonot,andarenotrequiredto, supporttheFuelBasket.,Section3.4.2:statedthatHOLTECinformedlicenseesto limittheheatloadbelowNRCapprovedlimits.Therewasnoneedfor suchanotificationandHOLTECdidnotmakethisnotification.
InformationtoClarifyNRCInspectionReportDiscussionofViolationB. statesthatforthedesignchangefortheSSOs,Holtec completeda72.48screeningandincorrectlydeterminedthatawritten evaluationwasnotneeded.Notethatthe72.48forthedesignchange (1212)wasafullevaluation.
TheloadedCanistersdonotandneverhaveposedanyrisktopublichealth andsafety,asincorrectlyandcontinuouslyallegedbycertainactivistsin thesocialmedia.Weregrettheircanards.
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