ML14325A752

Grand Gulf, Unit 1 - License Amendment Request Application to Revise Current Fluence Methodology

ML14325A752
Person / Time
Site:	Grand Gulf
Issue date:	11/21/2014
From:	Mulligan K J Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML14325A758	List: ML14325A752
References
GNRO-2014/00080
Download: ML14325A752 (16)

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QEntergyOperations,Inc.P.O.Box756PortGibson,MS39150KevinMulliganSiteVicePresidentAh2&3C.0.GrandGulfNuclearStationttacmentsontainPRPRIETARYInformationTel.(601)437-7500GNRO-2014/00080Nov21,2014u.s.NuclearRegulatoryCommissionAttn:DocumentControlDeskWashington,DC20555-0001

REFERENCES:

LicenseAmendmentRequestApplicationtoReviseGrandGulfNuclearStationUnit1'sCurrentFluenceMethodologyfrom0EffectiveFullPowerYears(EFPY)ThroughtheEndofExtendedOperationstoaSingleFluenceMethodGrandGulfNuclearStation,Unit1DocketNo.50-416LicenseNo.291.SeverityLevelIVnon-citedviolationof10CFR50.59,"Changes,Tests,andExperimentsinvolvingthelicensee'sfailuretoobtainalicenseamendmentpursuantto10CFR50.90priortoimplementinganewmethodofevaluationfordeterminingreactorvesselneutronfluence;GrandGulfNuclearStation-NRCIntegratedInspectionReport05000416/2013004,datedNovember27,20132.U.S.NuclearRegulatoryCommissionLetter,"RequestsforAdditionalInformationfortheReviewoftheGrandGulfNuclearStation,LicenseRenewalApplication,"datedAugust28,2013(AccessionNo.ML13227A394)3.GrandGulfNuclearStationLetter,"ResponsetoRequestsforAdditionalInformation(RAI)set47,"datedSeptember23,2013(AccessionNo.ML13266A368)4.U.S.NuclearRegulatoryCommissionRegulatoryGuide,RegulatoryGuide1.190,datedMarch2001(AccessionNo.ML010890301)

DearSirorMadam:

InaccordancewiththeprovisionsofSection50.90ofTitle10CodeofFederalRegulations(10CFR),EntergyOperations,Inc.(Entergy)issubmittingarequestforanamendmenttoreviseourexistinglicensebasisforGrandGulfNuclearStation(GGNS),Unit1.TheproposedamendmentistoreviseGrandGulfNuclearStation,Unit1'slicensebasistoadoptasinglefluencemethod.Thischangeisneededtoaddressalegacyissueinwhichthe GNRO-2014/000BOPage2of3currentmethodwasdeterminedtobeutHizedwithoutreceivingpriorNuclearRegulatoryCommission(NRC)approval.Attachment1providesadescriptionoftheproposedchange.Attachment2providesthetopicalreportfromMPMachineryandTesting,LLC.Attachment3providesthereportdocumentingtheapplicationofthesinglefluencemethodatGGNS.ThisreportalsoappliestotheMaximumExtendedLoadLineLimitPlus(MELLLA+)LicenseAmendmentRequest(LAR)inletter2013/00012(AccessionNo.ML13269A140).Althoughthisrequestisneitherexigentnoremergency,yourpromptreviewisrequested.Onceapproved,theamendmentshallbeimplementedwithin60days.MPMachineryandTesting,LLC(MPM)considerstheinformationprovidedinAttachments2and3tobeproprietaryandthereforeexemptfrompublicdisclosurepursuantto10CFR2.390.TheproprietaryinformationwasprovidedtoEntergyinanMPMtransmittal.Therefore,onbehalfofMPM,EntergyrequeststowithholdAttachments2and3frompublicdisclosureinaccordancewith10CFR2.390(b)(1).Thislettercontainsnonewcommitments.Ifyouhaveanyquestionsorrequireadditionalinformation,pleasecontactMr.JamesNadeauat(601)437-2103.Ideclareunderpenaltyofperjurythattheforegoingistrueandcorrect.ExecutedonNovember21,2014.Sincerely,KJM/rasAttachments:1.AnalysisofProposedSingleFluenceMethodology2.TopicalReportfromMPMachineryandTesting,LLC:MPM-614993,"BenchmarkingofMPMMethodsforBWRNeutronTransportCalculations,"November,2014.3.SingleFluenceMethodAppliedtoGGNS:MPM-B14779Revision1,"NeutronTransportAnalysisforGrandGulfNuclearStation,"November,2014.cc:Seenextpage GNRO-2014/00080Page3of3cc:withAttachmentandEnclosuresU.S.NuclearRegulatoryCommissionATTN:Mr.JohnDaily,NRRlDLRMailStopOWFN/11F111555RockvillePikeRockville,MD20852-2378cc:withoutAttachmentandEnclosuresU.S.NuclearRegulatoryCommissionATTN:Mr.MarkDapas,(w/2)RegionalAdministrator,RegionIV1600EastLamarBoulevardArlington,TX76011-4511NRCSeniorResidentInspectorGrandGulfNuclearStationPortGibson,MS39150U.S.NuclearRegulatoryCommissionATTN:Mr.AlanWang,NRRlDORL(w/2)MailStopOWFN8B1Washington,DC20555-0001Dr.MaryCurrier,M.D.,M.P.HStateHealthOfficerMississippiDepartmentofHealthP.O.Box1700Jackson,MS39215-1700 Attachment1GNRO-2014/00080AnalysisofProposedSingleFluenceMethodology Attachment1toGNRO-2014/000BOPage1of121.0DESCRIPTIONTheproposedamendmentrevisestheGrandGulfNuclearStation,Unit1(GGNS)licensebasestoadoptasinglefluencemethodologyfrom0EffectiveFullPowerYears(EFPY)throughtheendofextendedoperations.ThischangeisneededtoaddressalegacyissueinwhichthecurrentmethodwasdeterminedtohaverequiredNuclearRegulatoryCommission(NRC)approvalpriortobeingutilized,andalsoappliestotheMaximumExtendedLoadLineLimitPlusAnalysisPlus(MELLLA+)LicenseAmendmentRequest(LAR)(AccessionNo.ML13269A140).Thenewfluencemethodologyisreferredtobelowasthe"singlefluencemethod"toindicatethatallcalculationsareperformedinaconsistentmanner.ThemethodologyisdescribedindetailinReferences1and2whichgivetheresultsofthemethodologybenchmarkinganalysisandtheapplicationofthemethodologytotheGGNSfluenceanalysiscoveringoperationforthefirst21fuelcycles.2.0BACKGROUNDDuringtheGGNSLicenseRenewalprocess,itwasdeterminedthatthecurrentfluencemethodologyshouldhavereceivedNRCapprovalpriortobeingutilized.ThisresultedinaSeverityLevelIVNon-CitedViolation(NCV)of10CFR50.59,"Changes,Tests,andExperiments"involvingfailuretoobtainalicenseamendmentpursuantto10CFR50.90priortoimplementinganewmethodofevaluationfordeterminingreactorvesselneutronfluence,asdocumentedintheGrandGulfNuclearStation-NRCIntegratedInspectionReport05000416/2013004,datedNovember27,2013.LicenseRenewalApplication(LRA)LicenseAmendmentRequestResponsetoRequestforAdditionalInformation(RAI),set47,question5response,stated,inpart:GGNSRAI4.2.1-2cResponse5)AsupplementalresponsetothisRAIisbeingdevelopedandwillbeprovidedtotheNRC.Thesupplementalresponsewillprovidetheanswerstothefollowingquestions:a)PleaseprovidefluencevaluesthathavebeendeterminedfromBeginningOfLifetoEndofLifeExtendedinaccordancewithasinglemethod.i)IfthemethodisNRC-approvedinsofarasitappliestovesselfluencecalculations,providethereferencetothestaff-acceptedmethodology.ii)IfthemethodisnotNRC-approved,providetheplant-specificcalculationsanddocumentation,andincludesufficientinformation,toenabletheNRCstafftodeterminewhetherthecalculationadherestoNRCRegulatoryGuide(RG)1.190,"CalculationalandDosimetryMethodsforDeterminingPressureVesselNeutronFluence,"orotherjustificationasrequiredtoestablishthatthefluencecalculationisacceptable.iii)RefertoRegulatoryPosition3,"Reporting,"forthespecificdocumentationrequiredtoestablishadherencetoNRCRG1.190.

Attachment1toGNRO-2014/00080Page2of123.0TECHNICALANALYSIS3.1ApplicabilityEntergyhasreviewedtheU.S.NuclearRegulatoryCommissionRegulatoryGuide,RG1.190(Reference3).ThisguidedescribestheapplicationandqualificationofamethodologyacceptabletotheNRCstafffordeterminingthebest-estimateneutronfluenceexperiencedbymaterialsinthebeltlineregionoflightwaterreactor(LWR)pressurevessels,aswellasfordeterminingtheoveralluncertaintyassociatedwiththosebest-estimatevalues.EntergyhasconcludedthattheproposedfluencemethodologycomplieswiththeguidanceofRG1.190,andthereforeisappropriatetobeutilizedatGGNS.3.2DeterminationofcompliancewithRG1.1903.2.1RegulatoryPosition(RP)ComplianceDiscussion.FLUENCECALCULATIONMETHODSRP1.3FluenceDetermination.Absolutefluencecalculations,ratherthanextrapolatedfluencemeasurements,mustbeusedforthefluencedetermination.GGNSResponse:AllcalculationsperformedusingtheGGNSproposedmethodologyuseabsolutefluencecalculations.ThismeetstherequirementofRP1.3.

Attachment1toGNRO-2014/00080Page3of12RP1.1.1ModelingData.Thecalculationmodeling(geometry,materials,etc.)shouldbebasedondocumentedandverifiedplant-specificdata.GGNSResponse:TheGGNSproposedmethodologyisbasedondocumentedandverifiedplant-specificdata.Further,thecalculationsuseas-builtdataforplantstructuresandmaterialcompositionswheneverthesedataareavailable.Thefueldataisspecificforeachfuelcycleandincludesresultsforpowerdistributionsandwaterdensitiestakenfromthefueldepletionanalysis.ThismeetstherequirementofRP1.1.1.RP1.1.2NuclearData.ThelatestversionoftheEvaluatedNuclearDataFile(ENDF/B)shouldbeusedfordeterminingnuclearcross-sections.Cross-sectionsetsbasedonearlierorequivalentnuclear-datasetsthathavebeenthoroughlybenchmarkedarealsoacceptable.Whentherecommendedcross-sectiondatachange,theeffectofthesechangesonthelicensee-specificmethodologymustbeevaluatedandthefluenceestimatesupdatedwhentheeffectsaresignificant.GGNSResponse:ThecalculationsusetheBUGLE-96crosssectionsetwhichisbasedonthelatestversion(VI)oftheEvaluatedNuclearDataFile(ENDF/B).ThismeetstherequirementofRP1.1.2.RP1.1.2Cross-SectionAngularRepresentation.Indiscreteordinatestransportcalculations,aP3angulardecompositionofthescatteringcross-sections(ataminimum)mustbeemployed.GGNSResponse:AllcalculationsuseaP3angulardecompositioninaccordancewithregulatoryguide.ThismeetstherequirementofRP1.1.2.RP1.1.2Cross-SectionGroupCollapsing.Theadequacyofthecollapsedjoblibrarymustbedemonstratedbycomparingcalculationsforarepresentativeconfigurationperformedwithboththemasterlibraryandthejoblibrary.GGNSResponse:AllcalculationsareperformedwiththeBUGLE-96librarywhichiscollapsedto47neutrongroups.Thislibraryhasbeenthoroughlybenchmarked.ThismeetstherequirementofRP1.1.2.RP1.2NeutronSource.Thecoreneutronsourceshouldaccountforlocalfuelisotopicsand,whereappropriate,theeffectsofmoderatordensity.Theneutronsourcenormalizationandenergydependencemustaccountforthefuelexposuredependenceofthefissionspectra,thenumberofneutronsproducedperfission,andtheenergyreleasedperfission.GGNSResponse:Theneutronsourceiscalculatedtakingintoaccountchangesinneutronsperfission,energyperfission,andtheaveragefissionspectrumwhichdevelopsastheUranium-235isburnedandother Attachment1toGNRO-2014/00080Page4of12isotopes,suchasPu239,increaseinfissionfraction.ThismeetstherequirementofRP1.2.RP1.2End-of-LifePredictions.Predictionsofthevesselend-of-lifefluenceshouldbemadewithabest-estimateorconservativegenericpowerdistribution.Ifabestestimateisused,thepowerdistributionmustbeupdatedifchangesincoreloadings,surveillancemeasurements,orotherinformationindicateasignificantchangeinprojectedf1uencevalues.GGNSResponse:GGNShascalculatedthefluenceforeverycycleuptothepresent.Thisgivesthemostaccuratevalueofthepresentfluence.Extrapolationstofuturetimesaremadeusingbestestimatevaluesoffuturefueldesignsinacycle21bestestimateprojectioncycle.Aschangesinfuelcoreloadingsaremade,updatedextrapolationswillbemade.Further,thefluxvaluesfromthecycle21transportcalculationweremultipliedwithafactorof1.1appliedforprojectiontoexposuresaftercycle21.This10%)conservatismwasappliedbyEntergytoensurethatfluenceestimatesremainconservative.Periodiccycletransportupdatesareplannedtoensurethe100/0factoradequatelycoversfutureas-burnedfluxes.ThismeetstherequirementofRP1.2.RP1.3.1SpatialRepresentation.Discreteordinatesneutrontransportcalculationsshouldincorporateadetailedradialandazimuthal-spatialmeshof-2intervalsperinchradially.Thediscreteordinatescalculationsmustemploy(ataminimum)anSaquadratureand(atleast)40intervalsperoctant.GGNSResponse:Thepresentmethodologymeetsorexceedstheserequirements.All3DcalculationswereperformedwithanS16quadrature.TheR-8modelincluded215meshpointsintheradialdirection.Theradialmeshcoverstherangefromthecenterofthecoretoabout15inchesintothebiologicalshield.Thelargenumberofmeshpointswasusedtoaccuratelycalculatetheneutronfluxtransportfromthecoreedgetotheoutsideofthevessel.Intheazimuthaldirection,185meshpointswereusedtomodelaquadrantofthereactor.Inspectionofthefuelloadingpatternsindicatedthatonlyminordeviationsfromquartercoresymmetrywerepresent,andthesewerenotsignificant.However,therearesomedeviationsfromoctantfuelsymmetryandthese,togetherwiththequadrantsymmetryofthejetpumps,ledtotheuseofthequartercoremodel.The185azimuthalpointsprovidedgooddefinitionofthevariationofthecoreedgewithangleandaccuratelydefinedtheazimuthalfluxvariationintheshroud.Intheaxialdirection,the3DmodelextendspastBAFtoabout18inchesbelowtheH7shroudweld.ThemodeloftheregionabovethetopguideextendsaxiallypastthetopguideweldH1byanaxialextentof18inches.Thisresultedinatotalof246meshpointsintheaxialdirection,with105axialmeshesin Attachment1toGNRO-2014/00080Page5of12thecoreregion.Thisresultedinamodelwithover9.7millionmeshesinthe3Dmodel.ThismeetstherequirementofRP1.3.1.RP1.3.1MultipleTransportCalculations.Ifthecalculationisperformedusingtwoormore"bootstrap"calculations,theadequacyoftheoverlapregionsmustbedemonstrated.GGNSResponse:Itwasnotnecessarytousebootstrappingforthesecalculationssothisrequirementdoesnotapply.RP1.3.2PointEstimates.Ifthedimensionsofthetallyregionorthedefinitionoftheaverage-fluxregionintroduceabiasinthetallyedit,theMonteCarlopredictionshouldbeadjustedtoeliminatethecalculationalbias.Theaverage-fluxregionsurroundingthepointlocationshouldnotincludematerialboundariesorbelocatednearreflecting,periodic,orwhiteboundaries.GGNSResponse:ThisrequirementonlyappliestoMonteCarlocalculationswhicharenotusedhere.Variancereductionmethodswerenotused.RP1.3.2StatisticalTests.TheMonteCarloestimatedmeanandrelativeerrorshouldbetestedandsatisfyallstatisticalcriteria.GGNSResponse:ThisrequirementonlyappliestoMonteCarlocalculationswhicharenotusedhere.RP1.3.2VarianceReduction.Allvariancereductionmethodsshouldbequalifiedbycomparisonwithcalculationsperformedwithoutvariancereduction.GGNSResponse:ThisrequirementonlyappliestoMonteCarlocalculationswhicharenotusedhere.RP1.3.3CapsuleModeling.Thecapsulefluenceisextremelysensitivetothegeometricalrepresentationofthecapsulegeometryandinternalwaterregion,andtheadequacyofthecapsulerepresentationandmeshmustbedemonstrated.GGNSResponse:Thecapsulegeometryismodeledusingas-builtdrawings.Thewaterbetweenthecapsuleandthevesselsurfaceisalsomodeledusingbuiltdrawings.ThemeshisrefinedintheregionofthecapsuleandtheadequacyofthemeshhasbeendemonstratedbytheaccuracyoftheCIMratiosforthecycle1dosimetryanalysis.ThismeetstherequirementofRP1.3.3.

Attachment1toGNRO-2014/00080Page6of12RP1.3.3SpectralEffectsonRTNDT.InordertoaccountfortheneutronspectrumdependenceofRTNDT,whenitisextrapolatedfromtheinsidesurfaceofthepressurevesseltotheT/4and3T/4vessellocationsusingtheE>1-MeVfluence,aspectralleadfactormustbeappliedtothefluenceforthecalculationofaRTNDT.GGNSResponse:Thisrequirementonlyappliestoextrapolationthroughthevesselanddoesnotaffectthebenchmarkcalculations.However,whenfluencewithinthevesselisrequired,thedisplacementperatom(dpa)extrapolationmethodologyisappliedtovesselcalculationsasspecifiedinRG1.99,Revision2.DataaresuppliedtoenableextrapolationusingdpacalculatedextrapolationorusingRG1.99Rev.2extrapolationtoaccountforthespectralshift.ThismeetstherequirementofRP1.3.3.RP1.3.5CavityCalculations.Indiscreteordinatestransportcalculations,theadequacyoftheS8angularquadratureusedincavitytransportcalculationsmustbedemonstrated.GGNSResponse:NocavitydosimetryworkhasbeenperformedatGGNS.RP1.4.1,1.4.2,1.4.3MethodsQualification.Thecalculationalmethodologymustbequalifiedbyboth(1)comparisonstomeasurementandcalculationalbenchmarksand(2)ananalyticuncertaintyanalysis.Themethodsusedtocalculatethebenchmarksmustbeconsistent(totheextentpossible)withthemethodsusedtocalculatethevesselfluence.Theoverallcalculationalbiasanduncertaintymustbedeterminedbyanappropriatecombinationoftheanalyticuncertaintyanalysisandtheuncertaintyanalysisbasedonthecomparisonstothebenchmarks.GGNSResponse:AnextensivebenchmarkingprogramhasbeencarriedouttoqualifytheMPMneutrontransportmethodology.AlloftherequirementsofRG1.190havebeenmet.Inparticular,allC/Mresultsfallwithinallowablelimits(+1-20%),anditwasdeterminedthatnobiasneedbeappliedtoMPMfluenceresults.Theuncertaintyanalysisindicatesthatallfluenceresultsinthebeltlineregionhaveuncertaintyoflessthan20%.TheresultsofthisanalysisaredocumentedinReferences1and2.ThismeetstherequirementofRP1.4.1,1.4.2,and1.4.3.RP1.4.3FluenceCalculationalUncertaintyandBiasEstimation.Thevesselfluence(1sigma)calculationaluncertaintymustbedemonstratedtobeS200kforRTPTSandRTNDTdetermination.Intheseapplications,ifthebenchmarkcomparisonsindicatedifferencesgreaterthan20%,thecalculationalmodelmustbeadjustedoracorrectionmustbeappliedtoreducethedifferencebetweenthefluencepredictionandtheupper1-sigmalimittowithin200/0.Forotherapplications,theaccuracyshouldbedeterminedusingtheapproachdescribedinRegulatoryPosition1.4,andanuncertaintyallowanceshouldbeincludedinthefluenceestimateasappropriateinthespecificapplication.

Attachment1toGNRO-2014/00080Page7of12GGNSResponse:AnextensiveevaluationofallcontributorstotheuncertaintyinthecalculatedfluencewasmadefortheBWRplantcalculationsperformedtodate.Thisevaluationindicatedthattheuncertaintyincalculatedfluencesinthereactorbeltlineregionisbelow200kasspecifiedintheguide.Inaddition,thecomparisonswithmeasurementsindicateagreementwellwithinthe20%limit.Theagreementofcalculationswithmeasurementstowithin+/-200/0uncertaintyindicatesthattheMPMcalculationscanbeappliedforfluencedeterminationwithnobias.ThismeetstherequirementofRP1.4.3.FLUENCEMEASUREMENTMETHODSRP2.1.1SpectrumCoverage.Thesetofdosimetersshouldprovideadequatespectrumcoverage.GGNSResponse:GGNSdoesnothavedosimetrysetsinstalledtoprovidespectrumdefinition.ThisisincommonwithGEBWRswhichhaveonlylimiteddosimetryinstalledinsurveillancecapsules.TheGGNSdosimetryanalyzedtodateisfromironwiresattachedtoasurveillancecapsuleandremovedafterthefirstcycleofoperation.CalculatedneutronspectraarevalidatedusingthedetailedmeasurementsfortestreactorsandthecalculationalbenchmarkincludedinRG1.190.ResultsaredocumentedinReference1.RP2.1.1DosimeterNuclearandMaterialProperties.Useofdosimetermaterialsshouldaddressmelting,oxidation,materialpurity,totalandisotopicmassassay,perturbationsbyencapsulationsandthermalshields,andaccuratedosimeterpositioning.Dosimeterhalf-lifeandphotonyieldandinterferenceshouldalsobeevaluated.GGNSResponse:TheGGNSdosimetrywirematerialcharacterizationwasperformedbyGE(Reference4).AllnuclearconstantsandparametersusedinthedosimetrycountingandanalysisfollowASTMstandardproceduresandusevalidatednuclearconstants.ThismeetstherequirementofRP2.1.1.RP2.1.2Corrections.Dosimeter-responsemeasurementsshouldaccountforfluenceratevariations,isotopicburnupeffects,detectorperturbations,selfshielding,reactioninterferences,andphotofission.GGNSResponse:Thefluenceratevariationsforthedosimetryremovedaftercycle1wereexplicitlytakenintoaccountbydividingthecycleinto9segmentsandcalculatingthecapsulefluencerateforeachsegment.Theisotopicburnupeffectsareaccuratelyaccountedforaspreviouslydiscussed.

Attachment1toGNRO-2014/00080Page8of12Theothereffectshaveallbeenevaluatedtobesmallornotapplicable.ThismeetstherequirementofRP2.1.2.RP2.1.3ResponseUncertainty.Anuncertaintyanalysismustbeperformedfortheresponseofeachdosimeter.GGNSResponse:UncertaintyanalysesforeachdosimeterhavebeenreportedinallofthesurveillancecapsulereportsperformedbyMPM.ForGGNS,GEperformedthecycle1dosimetryanalysis(Reference4).Theuncertaintyforeachcycle1dosimeterwasreported.ThismeetstherequirementofRP2.1.3.RP2.2Validation.Detector-responsecalibrationsmustbecarriedoutperiodicallyinastandardneutronfield.GGNSResponse:RegardingtheGGNScycle1dosimetryworkdonebyGE,responsecalibrationshavebeencarriedoutinthepastusingdocumentedprocedures.TheGEradiochemistrylaboratoryparticipatedinpastinterlaboratorydosimetrymeasurementcalibrationprogramsbothforfastreactorirradiations(InterlaboratoryLMFBRReactionRateProgram)(Reference5)andlightwaterreactorirradiations(LWRSurveillanceDosimetryImprovementProgram)(Reference6).Intheseprograms,dosimeterswereirradiatedinstandardneutronfieldsandmeasuredbymultiplelaboratories.Theseprogramsdemonstratedtheaccuracyofmeasurementsandimproyedthestate-of-the-art.RegulatoryPosition2.2isdated.Theaboveprogramsarecompletedandstandardfielddetectorresponseirradiationsarenolongerdone.Theseprogramsservedtheirpurposetodemonstratethevalidityofmeasurementuncertaintyestimates.Althoughthecalibrationprogramsenvisionedcontinuinguseofstandardfieldirradiations,thesearenolongerconsiderednecessaryandmoderncountingpracticesinvolvetheuseofNISTtraceablemixedgammasourcestoprovideaccurateenergyandefficiencyspectrometercalibrations.RP2.3Fast-NeutronFluence.TheE>1MeVfast-neutronfluenceforeachmeasurementlocationmustbedeterminedusingcalculatedspectrum-averagedcross-sectionsandindividualdetectormeasurements.Asanalternative,thedetectorresponsesmaybeusedtodeterminereactionprobabilitiesoraveragereactionrates.GGNSResponse:Measurement-to-Calculationratiosaredeterminedforeachdosimetermeasurementusingcalculateddetectorresponses(References1and2).ThismeetstherequirementofRP2.3.

Attachment1toGNRO-2014/00080Page9of12RP2.3Measurement-to-CalculationRatios.TheMICratios,thestandarddeviation,andbiasbetweencalculationandmeasurement,mustbedetermined.GGNSResponse:TheMICratios,standarddeviations,andcomparisonsbetweencalculationandmeasurementhavebeendoneandhavebeenreportedasdiscussedearlier(References1and2).ThismeetstherequirementofRP2.3.REPORTINGPROVISIONSRP3.1Neutronfluenceanduncertaintiesdetailsoftheabsolutefluencecalculations,associatedmethodsqualification,andfluenceadjustments(ifany)shouldbereported.Justificationandadescriptionofanydeviationsfromtheprovisionsofthisguideshouldbeprovided.GGNSResponse:ThereportontheGGNScalculationsmeetsallRG1.190reportingrequirements(Reference2).ThismeetstherequirementofRP3.1.RP3.2Calculatedmultigroupneutronfluencesandfluenceratesshouldbereported.GGNSResponse:Becauseoftheextensiveamountofdata,onlythefluencedistributionsforneutronswithenergygreaterthan1MeVarereported,exceptforthevesselwhereneutronswithenergygreaterthan0.1MeVanddpaarealsoreported.Themultigroupfluenceratesarepermanentlystoredforfutureaccessifrequired.Thesearenotseenashavinganyapplicationexceptforpossiblefuturedosimetryanalysis.Multigroupfluxvaluesarereadilyavailableforalldosimetrylocations.ThismeetstherequirementofRP3.2.RP3.2Thevalueandbasisofanybiasormodeladjustmentmadetoimprovethemeasurement-to-calculationagreementmustbereported.GGNSResponse:Nobiasisobservedandnoneisapplied(References1and2).ThismeetstherequirementofRP3.2.RP3.3Calculatedintegralfluencesandf1uenceratesforE>1MeVandtheiruncertaintiesshouldbereported.GGNSResponse:Theseareallreported(Reference2).ThismeetstherequirementofRP3.3.RP3.4MeasuredandcalculatedintegralE>1MeVfluencesorreactionratesanduncertaintiesforeachmeasurementlocationshouldbereported.TheMICratiosandthespectrumaveragedcross-sectionshouldalsobereported.

Attachment1toGNRO-2014/000BOPage10of12GGNSResponse:Thesearereportedforalldosimetrylocations(References1and2).ThismeetstherequirementofRP3.4.RP3.5Theresultsofthestandardfieldvalidationofthemeasurementmethodshouldbereported.GGNSResponse:Notapplicable.SpecificActivitiesandAverageReactionRatesRP3.5Thespecificactivitiesattheendofirradiationandmeasuredaveragereactionrateswithuncertaintiesshouldbereported.GGNSResponse:Thisiscontainedinallreportswithmeasureddosimetrydata.ThismeetstherequirementofRP3.5.RP3.5Allcorrectionsandadjustmentstothemeasuredquantitiesandtheirjustificationshouldbereported.GGNSResponse:Nocorrectionsmade.ThismeetstherequirementofRP3.5.CONCLUSIONSInconclusion,theproposedsinglefluencemethodfrom0EFPYthroughtheendofextendedoperationsisinfullcompliancewithRG1.190,anditsreferencedregulations,andensuresthefluenceinputstotheanalysisareappropriate.Therefore,theadoptionofthissinglefluencemethodisconsideredacceptableandmaintainsapplicablesafetymargins.4.0REGULATORYSAFETYANALYSISNRCRG1.190describestheapplicationandqualificationofamethodologyacceptabletotheNRCstafffordeterminingthebest-estimateneutronfluenceexperiencedbymaterialsinthebeltlineregionoflightwaterreactor(LWR)pressurevessels,aswellasfordeterminingtheoveralluncertaintyassociatedwiththosebest-estimatevalues.ThisrequestforlicenseamendmentprovidestheGGNS-specificactionstoresolvethenonconformingcondition.GGNShasdeterminedthattheproposedchangesdonotrequireanyexemptionsorrelieffromregulatoryrequirements,anddonotaffectconformancewithanydraftGeneralDesignCriteriadifferentlythandescribedintheGGNSUFSAR,asdescribedbelow.4.1ApplicableRegulatoryRequirements/CriteriaRegulatoryrequirement10CFRPart50,"DomesticLicensingofProductionandUtilizationFacilities"AppendixG,"FractureToughnessRequirements,"and10CFR50.61,"Fracture Attachment1toGNRO-2014/00080Page11of12ToughnessRequirementsforProtectionAgainstPressurizedThermalShockEvents",areregulationsthatensurethestructuralintegrityofthereactorpressurevesselforcooledpowerreactors.Chapter15,AccidentAnalysis,oftheStandardReviewPlan(NUREG-0800,StandardReviewPlanfortheReviewofSafetyAnalysisReportsforNuclearPowerPlants)assumesthepressurevesseldoesnotfail.Theproposedsinglefluencemethodfrom0EFPYthroughtheendofextendedoperationsisinfullcompliancewithRG1.190anditsreferencedregulationsandensuresthefluenceinputstotheanalysisarecorrect.Inconclusion,basedontheconsiderationsdiscussedabove,(1)thereisreasonableassurancethatthehealthandsafetyofthepublicwillnotbeendangeredbyoperationintheproposedmanner,(2)suchactivitieswillbeconductedincompliancewiththeCommission'sregulations,and(3)theissuanceoftheamendmentwillnotbeinimicaltothecommondefenseandsecurityortothehealthandsafetyofthepublic.4.2NoSignificantHazardsConsiderationDeterminationEntergyrequestsadoptionoftheproposedsinglefluencemethodfrom0EFPYthroughtheendofextendedoperations.Entergyhasevaluatedwhetherornotasignificanthazardsconsiderationisinvolvedwiththeproposedamendment(s)byfocusingonthethreestandardssetforthinTitle10CodeofFederalRegulations(10CFR)50.92,"IssuanceofAmendment,"asdiscussedbelow:1.Doestheproposedchangeinvolveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated?Response:No.Theproposedchangeadoptsasinglefluxmethodology.WhileChapter15,AccidentAnalysis,oftheStandardReviewPlan(NUREG-0800,StandardReviewPlanfortheReviewofSafetyAnalysisReportsforNuclearPowerPlants)assumesthepressurevesseldoesnotfail,thefluxmethodologyisnotaninitiatortoanyaccidentpreviouslyevaluated.Accordingly,theproposedchangetotheadoptionofthefluxmethodologyhasnoeffectontheprobabilityofanyaccidentpreviouslyevaluated.Therefore,theproposedchangedoesnotinvolveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated.2.Doestheproposedchangecreatethepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated?Response:No.Theproposedchangeadoptsafluxmethodology.Thechangedoesnotinvolveaphysicalalterationoftheplant(i.e.,nonewordifferenttypeofequipmentwillbeinstalled)orachangeinthemethodsgoverningnormalplantoperations.Thechangedoesnotalterassumptionsmadeinthesafetyanalysisregardingfluence.

Attachment1toGNRO-2014/00080Page12of12Therefore,theproposedchangedoesnotcreatethepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated.3.Doestheproposedchangeinvolveasignificantreductioninamarginofsafety?Response:No.Theproposedchangeadoptsasinglefluencemethodology.Theproposedchangedoesnotalterthemannerinwhichsafetylimits,limitingsafetysystemsettingsorlimitingconditionsforoperationaredetermined.TheproposedchangeensuresthatthemethodologyusedforfluenceisincompliancewithRG1.190requirements.Therefore,theproposedchangedoesnotinvolveasignificantreductioninamarginofsafety.Basedontheabove,Entergyconcludesthattheproposedchangepresentsnosignificanthazardsconsiderationunderthestandardssetforthin10CFR50.92(c),and,accordingly,afindingof"nosignificanthazardsconsideration"isjustified.5.0ENVIRONMENTALCONSIDERATIONTheproposedchangewouldnotchangearequirementwithrespecttoinstallationoruseofafacilitycomponentlocatedwithintherestrictedarea,asdefinedin10CFR20,andwouldnotchangeaninspectionorsurveillancerequirement.Theproposedchangedoesnotinvolve(i)asignificanthazardsconsideration,(ii)asignificantchangeinthetypesorsignificantincreaseintheamountsofanyeffluentthatmaybereleasedoffsite,or(iii)asignificantincreaseinindividualorcumulativeoccupationalradiationexposure.Accordingly,theproposedchangemeetstheeligibilitycriterionforcategoricalexclusionsetforthin10CFR51.22(c)(9).Therefore,pursuantto10CFR51.22(b),noenvironmentalimpactstatementorenvironmentalassessmentneedbepreparedinconnectionwiththeproposedchange.

6.0REFERENCES

1.MPM-614993,"BenchmarkingofMPMMethodsforBWRNeutronTransportCalculations,"November,2014.2.MPM-814779,"NeutronTransportAnalysisforGrandGulfNuclearStation",November2014.3.U.S.NuclearRegulatoryCommission,RegulatoryGuide1.190,datedMarch2001(AccessionNo.ML010890301)4."FluxWireDosimeterEvaluationforGrandGulfNuclearPowerStation,"GEReport35-0387,April1987.5.W.N.McElroy,"DataDevelopmentandTestingforFastReactorDosimetry",Nucl.Tech.25,177(1975).6.R.GoldandW.N.McElroy,"TheLightWaterReactorVesselSurveillanceDosimetryImprovementProgram(LWR-PV-SDIP):PastAccomplishments,RecentDevelopments,andFutureDirections,"ReactorDosimetry:Methods,Applications,andStandardization,ASTMSTP1001,HarryFarrarandE.P.Lippincott,eds.,AmericanSocietyforTestingandMaterials,Philadelphia,1989,pp44-61.