ML15286A140
| ML15286A140 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 10/13/2015 |
| From: | Siva Lingam Plant Licensing Branch IV |
| To: | Siva Lingam Plant Licensing Branch IV |
| Lingam S | |
| Shared Package | |
| ML15286A156 | List: |
| References | |
| CAC MF4988, CAC MF4989 | |
| Download: ML15286A140 (3) | |
Text
1 Burkhardt, Janet From:
Lingam, Siva Sent:
Tuesday, October 13, 2015 10:24 AM To:
Lingam, Siva
Subject:
Diablo Canyon 1 and 2 - PG&E Response to Questions on LAR 14-04 Associated with Leak Before Break for Fuel Structural Analysis (CAC Nos. MF4988 and MF4989) -
PUBLIC From:Schrader,Kenneth[1]
Sent:Wednesday,September23,20158:30PM To:George,Andrea<Andrea.George@nrc.gov>;Lingam,Siva<Siva.Lingam@nrc.gov>
Cc:Soenen,PhilippeR<PNS3@pge.com>;Wright,Michael(ENG)<MDW4@pge.com>;Nelson,EricP(DCPP)
<EPN1@pge.com>;Jahangir,Nozar<NxJ1@pge.com>;Zaitz,KristinMurray<KMMh@pge.com>;Schrader,Kenneth
<KJSe@pge.com>;Andrachek,Jim(andracjd@westinghouse.com)<andracjd@westinghouse.com>;DaveDunsavage (dunsavd@westinghouse.com)<dunsavd@westinghouse.com>;DaveSklarsky(sklarsdw@westinghouse.com)
<sklarsdw@westinghouse.com>
Subject:
[External_Sender]PG&EResponsetoQuestionsonLAR1404[CONTAINSPROPRIETARYINFORMATION]
Siva,Andrea,
BelowisthePG&Eresponsetothe5questionsoftheLAR1404,UseofLBBinthefuelstructuralanalysisanduseofthe fuelstructuralanalysistosatisfy10CFR50.46(b)(4).
1.Page2ofEnclosuretoletterdatedOctober2,2014states,inpart; Thechangeinthebreaklocationinthe2010fuelstructuralanalysiswasnotaddressedinthecorresponding10CFR 50.59evaluation.
Pleasestatethepurposeof10CFR50.59evaluationandprovideacopyoftheevaluation.
Response:Thepurposeforthe10CFR50.59evaluationwasfortheIntegratedHeadAssembly.
2.Page6ofEnclosuretoletterdatedOctober2,2014states,inpart;,SummaryoftheDiabloCanyonUnits1and2FuelStructuralAnalysisResultsfortheHosgriEarthquake andtheAccumulatorLineBreak,providesasummaryoftheresultsoftheDCPPFuelStructuralAnalysis.
PleaseprovideacomparisontoshowhowtheresultsoftheDCPPFuelStructuralAnalysisfortheHosgriEarthquakeand theAccumulatorLineBreakcomparewiththeoriginalanalysis.
Response:TheoriginalanalyseswereperformedforVantage5fuelanddocumentedinWestinghouseproprietary documentVantage5ReloadTransitionSafetyReportfortheDiabloCanyonPowerPlantUnits1and2,datedOctober 1988.Themaximumstructuralgridimpactforceswerecalculatedconsideringtwobreaklocations,areactorpressure vesselinletlimiteddisplacementLOCAbreakandadoubleendedreactorcoolantpumpoutletpipebreak,andthe limitingbreaklocationimpactforcewasused(basedonWCAP9401PAmethods).Themaximumstructuralgrid impactforceswerecalculatedconsideringaccelerationspectrafortheHosgriearthquake.TheresponsefortheLOCA accidentandseismicanalyseswerecombinedusingthesquarerootsumofsquares(SRSS)method.
ThemaximumZircaloyMIDgridforcesusingtheSRSSmethodweredeterminedforafullcoreofVantage5fueltobe
[]poundsforUnit1[lessthanthe[]poundsfortheAccumulatorlinebreakinpage4ofAttachment4tothe EnclosureofDCL14083]and[]poundsforUnit2[lessthanthe[]poundsfortheAccumulatorlinebreakinpage6
2 ofAttachment4totheEnclosureofDCL14083]whichwaslessthattheallowablegridcrushstrengthof[]poundsfor thegriddesignatthetime.TheLOCAanalysisforcesatthegridlocationwithlimitingSRSScombinedloadswere determinedtobe[]poundsforUnit1and[]poundsforUnit2.
ThemaximumIFMgridforcesusingtheSRSSmethodweredeterminedforafullcoreofVantage5fueltobe[]pounds forUnit1[lessthanthe[]poundsfortheAccumulatorlinebreakinpage4ofAttachment4totheEnclosureofDCL 14083]and[]poundsforUnit2[lessthanthe[]poundsfortheAccumulatorlinebreakinpage6ofAttachment4 totheEnclosureofDCL14083]whichwaslessthattheallowablegridcrushstrengthof[]poundsforthegriddesign atthetime.TheLOCAanalysisforcesatthegridlocationwithlimitingSRSScombinedloadsweredeterminedtobe[]
poundsforUnit1and[]poundsforUnit2.
3.Page5ofEnclosuretoletterdatedOctober2,2014states,inpart; TheLOCAloadforDCPPwasbasedontheloadsassociatedwithapostulatedpiperuptureintheaccumulatorline,the RCSbranchlinethatproducedthemostlimitingloads.TheearthquakeloadforDCPPwasbasedontheloadsassociated withtheHosgriearthquake.TheHosgriearthquakegridloadsweredeterminedbyanalysistobemorelimitingthanthe DoubleDesignEarthquakeandDesignEarthquakeloads.ThelimitingLOCAload,combinedwiththeHosgriearthquake loadusingtheSquareRootSumofSquares(SRSS)methoddidnotresultinanygriddeformationforDCPP.
PleasestatetheoverallimpactofShorelineFaultontheearthquakeloadsconsideredfortheevaluationdocumentedin letterdatedOctober2,2014?
TheNRCinalettertoPG&EonOctober12,2012(NRCReviewofShorelineFaultaccessionnumberML12073106) issuedtheresultsoftheirindependentconfirmatoryassessmentunderResearchInformationLetter,RIL1201)thestaff concludedthatShorelinescenarioshouldbeconsideredasalesserincludedcaseundertheHosgrievaluationandthe licenseshouldupdatethefinalsafetyanalysisreport,asnecessary,toincludetheshorelinescenario..Asaresultthe DiabloCanyonFSARhasbeenupdatedasrequestedbythestaff.ThereforethedesignbasisforDiabloCanyonremains astheDesignEarthquake/DoubleDesignEarthquakeandHosgrievaluation(asaboundingcase),andnoadditional analysisorreviewforshorelinefaultisnecessary.
4.Page3ofEnclosuretoletterdatedOctober2,2014,inpart;
TheNRCapprovedBELOCAmethodologyalsoaddressesgriddeformationinfuelassembliesthatarelocatedonthe peripheryofthecore,ifitisdeterminedtooccur,basedonthefuelstructuralintegrityanalyses(Reference9).However nogriddeformationwascalculatedtooccurinthefuelstructuralintegrityanalysesthatwereperformedforDCPP.
Reference9(WCAP12945PA)isapplicableonlytoUnit1analysis.Unit2analysiswasperformedinaccordancewith WCAP16009PA.PleaseprovidereferencetothedocumentprovidingjustificationfornogriddeformationforUnit2.
Response
TheBELOCAanalysesdonotdeterminewhetherthereisanypotentialfuelgriddeformation.Thefuelstructural analysesdetermineifthereisanypotentialfuelgriddeformation.
AsummaryofthefuelstructuralintegrityanalysisresultsforUnit2arediscussedonPage6ofAttachment4tothe EnclosureofDCL14083inthesectionentitled,Unit2CombinedSeismic(HosgriEarthquake[HOS])andLOCA (AccumulatorLineBreak[ACC])LoadCase.
ThequotedstatementintheisonlydiscussingthattheNRCapprovedBELOCAmethodologywouldaddressfuelgrid deformation,ifitisdeterminedtooccur,andnotthattheBELOCAmethodologycalculatespotentialfuelgrid deformation.
3 5.Regardingtheapplicabilityofthefuelstructuralanalysisresults(whichutilizeLBB)tosatisfy10CFR50.46(b)(4),
thecoolablegeometryECCSperformancecriteria,theNRCstaffpositiondoesnotsupportapprovalofthisportionofthe LAR.TheNRCstaffpositionontheapplicabilityofLBB,itsapplicabilitytolocaldynamiceffectsonly,andits nonapplicabilitytoECCSperformance(sinceECCSaddressesglobaldynamiceffects)iswelldocumentedinNUREG0800, StandardReviewPlan,Section3.6.3,andinFederalRegisternotices51FR12502,datedApril11,1986,FinalRuleto modifyGDC4;52FR41288,datedOctober27,1987,2ndFinalRuletoModifyGDC4;53FR1131,datedApril8,1988; and,54FR18649,datedMay2,1989.
Response
PG&EunderstandsLBBcannotbeusedfortosatisfyECCSperformancecriteria.
PG&Erequestsapprovaltousethefuelassemblystructuralanalysisresultstosatisfy,inpart,theEmergencyCore CoolingSystemPerformanceAcceptanceCriterion,10CFR50.46(b)(4),"CoolableGeometry."Thewordsinpartare includedinthePG&EdescriptionofthechangebecausetheDiabloCanyonECCSanalysesforpeakcladdingtemperature andlongtermcorecoolingtomeet10CFR50.46requirementsdomodeladoubleendedguillotinebreakinthecoldleg asrequiredby10CFR50.46.Thefuelassemblystructuralanalysesareperformedtodetermineifanyfuelgrid deformationoccursandtheseresultsarethenusedasaninputtotheECCSanalysestodemonstratecompliancewith 50.46(b)(4)fuelcoolablegeometryrequirementsinaccordancewiththeNRCapprovedWestinghouseBELOCA methodology(WCAP12945PA,AppendixC).Thefuelstructuralanalyses,unliketheECCSanalyses,require considerationofaconcurrentearthquakeandLOCAperSection4.2oftheSRP.
Thedeterminationoftheconfigurationofthefuelgrids(deformationornodeformation)fortheECCSanalysis,basedon thefuelstructuralanalysesforthelimitingRCSbranchlinebreakbasedonapplicationofleakbeforebreak,hasbeen approvedbytheNRCmultipletimesforlicensees(mostrecentlyfortheTurkeyPointExtendedPowerUprate).In Section4.2oftheNRCSafetyEvaluationfortheTurkeyPointExtendedPowerUprate,thestaffstated(includedinPage 9oftheEnclosureofthePG&EletterDCL14083)ThelicenseeevaluatedseismicandLOCAloadingusingtheapproved methodologydescribedinWCAP9401PAformixedcoreofDRFAandupgradefueldesigns,andafullcoreofthe upgradefueldesignattheEPUconditions.ByletterdatedMay18,2011,thelicenseeprovidedinitialresponsestothe NRCstaffRAI.ThecoreplatemotionsandverticalimpactsonthenozzleswereusedintheseismicandLOCAanalysesfor theEPUconditions.Thelicenseeappliedseverallimitingfuelloadingconfigurationsforthemixedcore.Thelargest branchlinebreaks,eithertheaccumulatorline(ACC)break,surgelinebreak,orRHRlinebreak,wereconsideredwhen generatingLOCAhydraulicforcingfunctionsusedasinputtotheanalysis.PG&Eisrequestingapprovaltoperformwhat wasapprovedforTurkeyPoint,thatistousethelargestbranchlinebreak(eithertheaccumulatorlinebreak,surgeline break,orRHRlinebreak)whengeneratingLOCAhydraulicforcingfunctionsforthefuelstructuralanalysis.
- Thanks,
KennethJ.Schrader RegulatoryServicesPacificGas&ElectricCo.
email:kjse@pge.com Phone:8055454328 Fax:8055453459