ML17037C366

Nine Mile Point Unit 1 - Letter Responding to the August 13, 1971 Letter Requesting Additional Information on the Partial Refueling Scheduled for September 19, 1971 and Enclosing Information on the Second, Third, and Fourth Questions

ML17037C366
Person / Time
Site:	Nine Mile Point
Issue date:	08/20/1971
From:	Brosnan T J Niagara Mohawk Power Corp
To:	Morris P A US Atomic Energy Commission (AEC)
References
Download: ML17037C366 (20)

Text

MagaraEo&mshPoeerCorporaHonSTITaacusoMewYorh.1320TJ.3roananTO:11Dr.NorrisDATEOFDOCUMENT:DATERECEIVEDLTR,8-2G<<VXMEMO.-8-~~<71PORT:ACTIONNECESSARYQNOACTIONNECESSARYQCONCURRENCECOMMENTORIG.:CC:OTHER'sined&59confEINO.:vll'(OTHERQDATEANSWERED:QBV:CLASSIF:POSTOFFICEUREG.NOIDESCRIPTIONI(MuatBaUnC!aSaified)htrreoux'-13-7l1tre+furnf.shingaddiinfo(answerstoquestions2,364onthepartialrefuelingofWineBilePointreactor..anmers'touestinasFILECODE:50-220REFERREDTODATE-24-7RECEIVEDBYDATE'""~'ue.1villbeSezeeeee~yteeogFilesCompBance{2)SkoyholtREMARKS:ThompsonDTXE(Laughlin)U.S.ATOMICENERGYCOMMISSION*U.S.GOVERNMENTPRINTINGOFFICER~1071Ma4WeafodMAILCONTROLFORMFoRMAEGGESSI6-60I 00tIIFlfIkCg~~tVJIls'4 NIAGARAMOHAWKPOWERCORPORATION,iII~JRfNIAGARA~)MOHAWKSYRACUSE,NEWYORK13202August20,1971eEf$/(p~,9COIIPII+@40gDr.PeterA,Morris,DirectorDivisionofReactorLicensingUnitedStatesAtomicEnergyCommissionWashington,D.C.20545

DearDr.Morris:

ReguiatoI'YFileCy.0-.220YourletterofAugust13,1971requestedadditionalinformationonthepartialrefuelingoftheNineMilePointreactorscheduledfor,September19,1971.Uponreceiptofthisletter,NiagaraMohawkimmediatelyinitiatedthepreparationofaresponse.Informationrequestedonthesecond,third,andfourthquestionsinyourletterofAugust13,1971isenclosed.Thexesponsetoyourfirstquestion,concerningtheconsequencesofpossibleloadingerrors,isinfinalstagesofpreparationandwillbeforwardedpromptlyuponcompletion.Verytrulyyours,,J.BrosnanVicePr~dentandChiefEngineerEnclosuresDOCKETEDUSAECAUG281971DREGIIUITORYII-5MAILSECTIONDOCKET'LERKb3757 e'tJbg-t%s'vp',Ig;rj

~~RE:T.J.BrosnanAugust20,1971responsetoDr.P.A.MorrisAugust13,.1971letter.2.Question:Inviewofthefuelfailuresexperiencedtodate,describemeasures~andprogramsyouareemployingorproposetoinstitutetoprovideimprovedqualityofgadolinium-bearingfuelasfabricatedand'naugmentedsurveillanceofthecorefuelduringoperations.'Answer:Fuelfaj.luresexperiencedtodatehavebeenattributedbyGeneralElectric'tolocalizedcladhydridingandtoaninfrequentoccurenceoftubingflaws.ThepresenceoflocalizedcladhydridinghasbeenconfirmedbyinvestigationsofdefectivefuelremovedfromtheDresdenUnit2andKRB(Germany)reactors.FueldischargedfromtheDresdenUnit2reactorduringtheJune1970andMarch1971outageswasinspectedbyGeneralElectrictodeterminethenatureandextentoffueldefects.Core"sipping"wasusedtoidentifythebundlescontainingleakerfuelrods.Eachoftheleakerfuelrodswasdisassembledandindividuallyinspectedbyultrasonicandeddycurrenttechniques.Theseresultsweresupplementedbyvisualexaminationofselectedrods.Detailedhot-cellexaminationswereperformedon12selectedfuelrodstoestablishthenatureoftheXuelrod.defects.and,to.detexmine.thecause.andtheconditionsleadingtothedefects.ThisinvestigationrevealedthecauseofcladperforationsintheDresden2fueltobelocalizedcladhydridingfromhydrogenousimpuritiesintroducedintotherodduringmanufacture.TheinvestigationofleakingfuelattheKRBreactorrevealedthepresenceoflocalizedcladhydriding,andinfrequentincidenceofrodperforationsduetotubingflawswasalsoindicated.Thoughafewgadoliniarodshaveexperiencedfailure,thequantityisstatisticallysmall,andnoneofthesefailureshavebeenattributedtothepresenceofgadolinia.Qualitycontrolofgadoliniumcontainingfuelrodshasbeendescribedinotherdocketsl.Reloadfuel.fortheNineMilePointNuclearStationiscurrentlybeingmanufacturedbyGeneralElectricCompanyattheirNilmingtonmanufacturingfacilityinaccordancewithanestablishedqualitycontrolprogram.SystematicprogramshavebeencarriedoutbyGeneralElectricatthei(ilmingtonfacilitytoeliminateanysourceofhydrogenousimpuritiesincurrentproductionfuelandtoeliminateordetectanytubingflaws,shouldtheyoccur.Allloadedfuelrodsarehotvacuumoutgassedjustpriortofinalweldingtoeliminateanyhydrogenous'impurities.The1.DocketSO-2S4;QuadCitiesStation,Units1and2;Amendment9;pp.3-5.2-1

~~

Answer(Cont'd):manufacturingstepsusedatNilmingtonforzircaloytubingmanufacturewererevisedtoeliminatecausesoftubingflawsandincreasednon-destructivetestingstepswereaddedtothetubingfinalinspection,includingincreasedfrequencyofultrasonicinspection.AsindicatedinourletterofJuly27,1971,NiagaraMohawkengineersanditsdesignatedagent,theNuclearAuditandTestingCompany,areconductinganindependentauditoXthequalityassuranceprogramattheNilmingtonfacilityduringthemanufactureofNiagaraMohawksreloadfuel.AlsoasstatedinourletterofJuly-27,1971,acompletevisualanddimensionalinspectionofallfuelwillbemadeatNineMilePointNuclearStationpriortoinsertingthefuelintothe'eactor.Duringnormaloperationofthestation,parametersrelatedtofuelperformancearemonitoredinaccordancewiththeNineMilePointNuclearStationTechnicalSpecifications.InadditionasurveillanceprogramonBoilingNaterReactorfuelwhichoperatesbeyondcurrentproductionfuelexperiencewillbeundertakenasitbecomesavailableforinspection.Thescheduleofinspectionsfortheleadfuelrodwithrespecttoexposure,linearheatgenerationrateandthecombinationofthesewillbecontingentupontheavailabilityofthefuelasinfluenced.by.plant.operating,andfacility,requirements.2~2 I,

RET.J.BrosnanAugust20,1971responsetoDr.P.A.MorrisAugust13,1971letter.Question:YourJuly27,1971letterstatedthattheperformanceofgadolinium-containingfuelhasbeendemonstratedsuccessfullyinotherBNRs.andthatwehavereviewedsuchfuelforseveralotherfacilities.ClarifyyourreferencestootherdocketstoindicatetheinformationthatisrelevanttotheproposedNMPoperationwithgadolinium-bearingfuelasregardsgadoliniumcontent,marginstofuelmeltingandclad.damage.duringsteady-.stateand.transientoperations,includinguncertaintiesinpowerdistributionasafunctionofburnupandsimilarlythemargin-to-fueldamageforcontrolroddropaccidentconditions.Answer:FuelcontainingvariousconcentrationsofgadoliniahasbeenutilizedintheHumboltBay,Dresden1andBigRockPointreactors.TheexperiencewiththisfuelhasbeenreportedtotheCommissionontheQuadCitiesStationDocket>.TheType.2reloadfuelproposedforNineMilePointcontainsGd203inconcentrationswithin.therangeofthisexperience.TheCommissionhasreviewedthe.use..of,gadoliniumcontainingfuelsimilartoNineMilePointType2reloadfuelonthedocketsforDresden22andQuadCities>.TheGd203'oncentrationsintheNineMilePointType2reloadfuelareless'thanthemaximumusedineitherDresden2orQuadCitiesfuel.ThelowerconcentrationsusedinNineMilePointfuelresultinhigherlinearheatgenerationrates(LHGR),fortheonsetoffuelmeltingandcladdamage(onepercentplasticstrain)thanthecorrespondingLHGP.'sapplicabletothegadoliniumcontainingfuelrodsinDresden2,asshowninTable3-.1.Bydesign,thegadoliniumcontainingfuelrodsinbothDresden-2andNineMilePointwilloperateataLHGRlessthanorequalto14.0kw/ft3.Therefore,themarginsbetweensteadystateoperationandfuelmeltingandcladdamage(onepercentplasticstrai'n)areactuallygreaterforNineMilePointwhencomparedtoDresden2.Themarginstofuel.meltingandcladdamageforgadolinium-containingfuelarealsogreaterforNineMilePointthanDresden2foralltransientswhichresultinthesamemaximumLHGRfortheU02fuelrodsbecauseofthehigherLHGR'scorrespondingtofuelmeltingandcladdamageforNineMile.Pointfuel.1.Dockets50-254and50-265;QuadCitiesStationUnits1and2;Amendment9,pp.3-5.2.Docket50-237;DresdenNuclearPowerStation,Unit2;TopicalReporttoDPR-19,"Modification71-1Refueling".3.Ibid2,pp.43-1

'Answer(Cont'd):ThemaximumexposuredependentlocalpeakingfactorcalculatedfortheNineMilePointreloadfuelisapproximately1.25andis,therefore,lessthanthedesignbasispeakingfactorof1.30.Amaximumpeakingfactorof1.27wascalculatedforfuelcontaininggadoliniuminDresden2".TheGd02concentrationoftheNineMiloPoint.fuelisdifferentthanthatotheDresden2fuel.BecauseofthisdifferencetheminimumenthalpiesatstartandendofGd202-002meltingarosome20cal/gmhigherfortheNineMilePointfuel;agreatermarginisaffordedtheNineMilePointgadoliniafuelascomparedtoDresden25.4,ibid2,pp.6.s5.Docket50-237,DresdenNuclearPowerStation,Unit2,TopicalReporttoDPR-19,SupplementNo.1,Table3.3-2

TABLE3-1LINEARHEATGENERATIONRATESFOROPERATING,FUELMELTING,CLADDAMAGECONDITIONSNinehfilePoint6Dresden27OperatingLHGR(kw/ft)UORod217.5Gd0-UORod23214.0Gd0-UORod23214.0OnsetofFuelMelting(kw/ft)21.519.517.3CladDamage(kw/ft)28.026.525.26.Docket50-220;Letter,NiagaraMohawk(T.J.Brosnan)toAtomicEnergyCommission(Dr.PeterA.Morris)datedJuly27,1971,pp.2-3.7.Docket50-237;DresdenNuclearPowerStation,Unit2;TopicalReporttoDPR-19,"h(odification71-1Refueling";pp.D-2.3-3

0Re:T.J.BrosnanAugust20,1971responsetoDr.P.A.MorrisAugust13,1971letter.4.Question:DescribeindetailtheeffectoftheproposedfuelonanalyticalresultsobtainedfromthestudyyouareperforminginresponsetoourlettertoyoudatedJuly22,1971,concerningtheAECinterimacceptancecriteriafortheperformanceofemergencycorecoolingsystems.Answer:Enrichmentlevelsofthereloadfuelareslightlyhigherthanthoseoftheinitialcorebundles.Inaddition,thereloadbundlesincorporateaburnablegadoliniumpoisonmixedwithuraniumoxideinfourfuel'rodsineachbundle.Thedistributionoflocalpeakingfactorsandchangesinpeakingfactorswithexposurearedifferentwiththereloadbundles,thoughthemaximumdesignlocalpeakingfactorisnotincreased.Thesedifferencesaffectdirectlytheresultsoftheloss-of-coolantaccidentanalyses.Theseanalyseshavebeenredoneforuseofreloadfuelatanypositioninthecore,includingthemostreactiveposition.TheyindicatethattheresultsoftheanalysesfortheinitialcorefueldesignprovidedinourletterofAugust20,1971.tothe..Commission,remainthesame.forthereloadfuelexceptasindicatedbelow.Thesame'single-failureeventsdescribedinourletterofAugust20,1971totheComissionfortheinitialcorefuelwereusedinthereloadanalysesandthecompleterangeofpeakingfactors,fromthebeginningtotheendofbundlelife,wasstudied.ResultsareshowninFigure4-1.Themaximumpeakcladtemperatureofthereloadedcoreoccursat10,000WD/T,eventhoughthehighestlocalpeakingfactorisnotthenatitsmaximum.Amaximumpeakcladtemperatureof226SFwasobtainedfromthisstudyforthedesignbasisaccident;thecorrespondingpeakcladtemperaturefortheworstcaseintermediatesizebreakis224SF.Cladembrittlementcontinuestobeavoidedforallbreaksuptoandincludingthedesignbasisaccidentsincethemaximumlocalcladdingoxidationislessthan7.0~oforthereloadcorecase.Thesedatacomparecloselytothosecalculatedfortheinitialcorebundles.Thus,theNineMilePointreloadedcorewillcontinuetobeinconformancewiththeCommission'sInterimAcceptanceCriteriawhenreloadfuelofthetypedescribedinourletterofJuly27,1971isemployedatanylocation-inthecore.OurletterofJuly27,1971alsodiscussedreconstitutionofinitialcorefuel.Thereconstitutedbundleswillcontainfuelrodstakenfromotherinitialcorebundles.Eachreplacementrodwillbeofthesameinitialenrichmentasthedefectiveroditreplaces.Exposuredifferencesbetweendefectiveandreplacementrodswillbelimitedtovaluessuchthatthebundlepowerwillbeessentiallythesameasfortheinitialcorefuel.4-1

Answer(Cont'd]:Inparticular,replacementrodexposurewillbethesameorgreaterthanthatofthedefectiveroditreplaces.Calculationswilldetailtheexposurehistoryofeachfuelrodintheaffectedbundlesandexposuredifferencewillbecontrolledsuchthatthereplacementrodorrodswillresultinthepeakcladtemperaturesfollowingaloss-of-coolantaccidentthesameorlessthanthatcalculatedfortheinitialcorebundledesign.4-2

~~

NINEMILEPOINTNUCLEARSTATION.2300.EFFECTOFFUELBUNDLEEXPOSUREONPEAKCLADDINGTEMPERATURE-RELOADFUELMaximumDesignBasisAccident22002IOOl-C5lD2000DIntermediateBreakl90000FIGURE4-I5000l0000FUELBUNDLEEXPOSURE(MWD/T)I5000

• ~~lafr'ht