ML19143A472

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Presentation Material for 6/03/19 Pre-Submittal Meeting Integrated Leak Rate Test Extension License Amendment Request
ML19143A472
Person / Time
Site: Millstone 
Issue date: 06/03/2019
From:
Dominion Energy Nuclear Connecticut
To:
Plant Licensing Branch 1
Guzman R
References
EPID L-2019-LRM-0026
Download: ML19143A472 (15)
v • d • e


Text

Millstone Power Station Unit 3 Pre-Submittal Teleconference for License Amendment Request to Extend Containment Leakage Testing Intervals June 3, 2019 1

  • BackgroundandReasonforAmendment
  • ProposedChanges
  • TechnicalJustificationforChanges
  • Conclusions
  • Schedule
  • 10CFR50,AppendixJwasamendedaftertheinitiallicensing ofMPS3toprovideaperformancebasedapproach(OptionB) forthecontainmentleakagetestingrequirementsILRT(Type A)andlocalleakratetesting.

Performancebasedtestintervalsarebasedon considerationoftheoperatinghistoryofthecomponent andresultingriskfromitsfailure.

  • NEITopicalReport9401providedaguidelinetotheindustry forimplementingtheperformancebasedOptionB.

NRCsSEsforNEI9401Revision2Aand3Aconcluded thatLicenseescouldimplementthisoptionalapproachas describedinthedocuments,subjecttothelimitationsand conditionsoftheSEs.

Background

June 3, 2019 3

  • DENCproposesa LARforMPS3,whichwillreviseTS6.8.4.f, "ContainmentLeakageRateTestingProgramto:

ReplacethereferencetoRG1.163withareferencetoNEI 9401,Revision3A.

Includeadditionalwordingtoimposethelimitationsand conditionsspecifiedinNEI9401,Revision2A.

  • ThesechangeswouldallowDENCtoextendtheTypeA(ILRT) intervalfrom10yearsto15yearsandtheTypeClocalleak ratetestintervalfrom60monthsto75monthsforMPS3.

ProposedChanges June 3, 2019 4

TestingHistoryandInspections Areviewofthelast3ContainmentLeakRateTestprogramresults indicatethatmeasuredleakratesmeettheapplicableTSlimits and/orAppendixJcriterionwithmargin.

Onlyexceptionwasduringthe1998asfoundTypeAtest,when failuresresultedfromacontainmentpurgesupplyissue(LER96 01200)

Containmentinspectionsperformedinaccordancewithotherplant programsservetoprovideahighdegreeofassurancethatthe containmentwillnotdegradeinamannerthatwouldchallenge containmentintegrity.

BasedonthelatestASMEXISubsectionIWE/IWLcontainment inspectionsperformedatMPS3,therearenoactivedegradation mechanismspresent.

TechnicalJustificationforChanges June 3, 2019 5

MPS3PRABackground

  • DENCpreparedaconfirmatoryriskimpactassessmentin accordancewiththemethodologydescribedinEPRIReportNo.

1009325,Revision2forILRTExtensions.

  • TheassessmentconfirmedthegeneralfindingsofNUREG1493 (PerformanceBasedContainmentLeakTestProgram)ona plantspecificbasis,consideringsevereaccidentsforMPS3.

IncreasingtheILRTintervaltofifteenyearsisconsideredto beaninsignificantchangeinrisksinceitrepresentsasmall changetotheMPS3riskprofile.

TechnicalJustificationforChanges June 3, 2019 6

MPS3PRAScope

  • ThescopeoftheMPS3PRAmodelincludesInternalEventand InternalFloodHazards.
  • InthisLAR,FireandSeismicHazardswillbeassessedusinga boundinganalysis,consideringIPEEEinformation.
  • OtherExternalHazardswillbeassessedqualitatively.

TechnicalJustificationforChanges June 3, 2019 7

MPS3PRAQuality

  • IntheSE(ADAMSAccessionNo.ML081140105)forEPRIReport 1009325andNEI9401Revision2theNRCstated,inpart:

theNRCstaffwillexpectthelicenseessupportingLevel 1/LERFPRAtoaddressthetechnicaladequacy requirementsofRG1.200,Revision1.CapabilitycategoryI ofASMERASa2003shallbeappliedasthestandard,since approximatevaluesofCDFandLERFandtheirdistribution amongreleasecategoriesare sufficientforuseintheEPRI methodology.

TechnicalJustificationforChanges June 3, 2019 8

MPS3PRAQuality

  • DENCrecentlycontractedwithWestinghousetoperforma focusedscopepeerreviewoftheMPS3PRAtodetermine compliancewithAddendumAoftheASME/ANSPRAStandard andRG1.200,Revision2.
  • Thisreview,whencombinedwithapreviousfocusedscope peerreview,resultedinacompletereviewoftheMPS3Internal EventandInternalFloodPRAmodelagainstthefullscopeof ASME/ANSRASa2009/RG1.200R2technicalrequirements.

TechnicalJustificationforChanges June 3, 2019 9

MPS3PRAQuality

  • TheMPS3PRAmodelhas106F&OsofFindingsignificance.

Allfindingshavebeenassessedanddispositionedforthis application.

TheLARincludesatablewhichdiscussesthedisposition foreachfinding.Thetableusesatemplatefrom10CFR 50.69riskinformedcategorizationlicenseamendments.

TechnicalJustificationforChanges June 3, 2019 10

MPS3PRAQuality

  • Eachfindingwasdispositionedusingoneofthefollowing techniques:

Qualitativeassessment Incorporationintoaquantitativesensitivityanalysiswhich assessedthecumulativeimpactofPRAfindings, uncertaintiesandpendingchanges TechnicalJustificationforChanges June 3, 2019 11

ThePRAmodel(including106findings)isacceptableforILRTsurveillance applicationwiththefollowingbasis:

TheILRTriskassessmentmethodologyemploysanumberof simplifyingassumptionswhichapplyconservativebiastothe evaluation.PertheNRCSEforEPRIReport1009325:

approximatevaluesofCDFandLERFandtheirdistributionamongrelease categoriesaresufficientforuseintheEPRImethodology.

Thesubjectofthefindingsdonotadverselyimpacttheabilityofthe MPS3modeltosupportthisapplication.PertheWestinghousePeer ReviewReport:

Thefindingsandsuggestionsprimarilypertaintomodelingdetailsandtothe clarityandcompletenessofdocumentation.Overall,theMPS3PRAwasfound tosubstantiallymeettheASME/ANSPRAStandard,RASa2009atCapability CategoryII ThesensitivityanalysisdemonstratesthattheILRTriskanalysishas verylowsensitivitytothecumulativeimpactofPeerReviewfindings.

TechnicalJustificationforChanges June 3, 2019 12

  • DENCisadoptingtheguidanceofNEI9401,Revision3A,and thelimitationsandconditionsspecifiedinNEI9401,Rev.2A, foruseintheMPS310CFR50,AppendixJtestingprogram.
  • BasedonthepreviousILRTtestsconductedatMPS3,DENC concludesthatextensionofthecontainmentTypeA(ILRT) intervalfrom10to15yearsandtheTypeClocalleakratetest from60monthsto75monthsrepresentminimalrisksto increasedleakage.
  • ThefindingsoftheMPS3riskassessmentconfirm,onaplant specificbasis,thatextendingtheTypeA(ILRT)intervalfrom10 to15yearsresultsinasmallchangetotheMPS3riskprofile.

Conclusions June 3, 2019 13

  • NRCPreSubmittalMeetingon06/03/2019
  • SiteFacilitySafetyReviewCommitteeReviewtargetedforend ofJune2019
  • LARSubmittaltotheNRCexpectedbyendofJuly2019
  • NRCApprovalrequestedbyendofJuly2020 Schedule June 3, 2019 14

ANS AmericanNuclearSociety ASME AmericanSocietyofMechanical Engineers CDF CoreDamageFrequency CFR CodeofFederalRegulations DENC DominionEnergyNuclear Connecticut EPRI ElectricPowerResearch Institute F&O Finding&Observation IPEEE IndividualPlantExaminationof ExternalEvents ILRT IntegratedLeakRateTesting LAR LicensingAmendmentRequest Acronyms June 3, 2019 15 LERF LargeEarlyReleaseFrequency MPS3 MillstonePowerStationUnit3 NEI NuclearEnergyInstitute NRC NuclearRegulatoryCommission PRA ProbabilisticRiskAssessment RG RegulatoryGuide SE SafetyEvaluation TS TechnicalSpecifications

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