ML17227A343

Proposed Tech Spec 5.3.1 Re Fuel Assemblies

ML17227A343
Person / Time
Site:	Saint Lucie
Issue date:	03/13/1992
From:	FLORIDA POWER & LIGHT CO.
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ML17227A342	List: ML17227A340 ML17227A343
References
NUDOCS 9203180143
Download: ML17227A343 (10)

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DESIGNFEATURES5.2.1.2SHIELDBUILDINGa.Minimumannularspace=4feet.b.Annulusnominalvolume=543,000cubicfeet.C.Nominaloutsideheight(measuredfromtopoffoundationbasetothetopofthedome)=230.5feet.d.Nominalinsidediameter=148feet.e.Cylinderwallminimumthickness=3feet.f.Domeminimumthickness=2.5feet.g.Domeinsideradius=112feet.DESIGNPRESSUREANOTEMPERATUREI5.2.2Thecontainmentvesselisdesignedandshallbemaintainedforamaximuminternalpressureof44psigandatemperatureof264'F.PENETRATIONS5.2.3PenetrationsthroughthecontainmentstructurearedesignedandshallbemaintainedinaccordancewiththeoriginaldesignprovisionscontainedinSections3.8.2.1.10and6.2.4oftheFSARwithallo'wancefornormaldegrada-tionpursuanttotheapplileSurveillanceReuirements.53REACTORCOREg+'Z/rreyg@or~+gg~y~~oc/geeagp/jrpqg+Jy~~+ppg~FUELASSEMBLIES4Pf~~~+~PM~41PPc/~~J-/goalcz~+ZPPypQ~gg~r,~~5.3.1Thereacorcoreshallcona>n~ue1~3~mbreswseachfuelassemblycontainingamaximumof176fuelrodscladwithZircaloy-4.Eachfuelrodsha(haveanominalactivefuellengthofbetween134.1and136.7~414kfuelasseppbliesshallcontainfuelrodsofthesamenominalactivefuellength..~Theinitialcoreloadingshallhaveamaximumenrichmentof2.83weightpercentU-235.Reloadfuelshallbesimilarinphysicaldesigntotheinitialcoreloading.5.3.2ExceptforspecialtestasauthorizedbytheNRC,allfuelassembliesundercontrolelementassembliesshallbesleevedwithasleevedesignpreviouslyapprovedbytheNRC.ST;.LUCIE-UNIT.15-4AmendmentNo.3g,M,769203180i439203i3PDR*DOCK05000335PPDR I

St.LucieUnit1DocketNo.50-335ProposedLicenseAmendmentAlternativeReuirementsforFuelAssembliesATTACHMENT2SAFETYANALYSISIntroductionThisproposedlicenseamendmentrevisestheSt.Lucie1TechnicalSpecificationsDesignFeaturesSection5.3.1topermittheuseoffuelassemblydesignsthatarenotlimitedtoamaximumuraniumweight.ReloadfuelassemblieswillbelimitedtothosedesignsthathavebeenanalyzedusinganNRCapprovedmethodologyandshownbytestsoranalysestocomplywithallapplicabledesignandsafetycriteria.ThefuelassemblydescriptionintheDesignFeaturesSectionoftheTechnicalSpecificationsprovidesadescriptionoftherequiredcharacteristicsofreloadfuel.TheSt.Lucie1TechnicalSpecificationDesignFeaturesSection5.3.1requiresthateachfuelrodinafuelassemblyshallcontainamaximumtotalweightof2250gramsuranium.However,theCycle11reloadwasdesigned,analyzedandfabricatedtocontainapproximately2275gramsofuraniumperfuelrod.ThepurposeofthisrequestistorevisethissectionoftheTechnicalSpecificationstopermittheuseoffuelassemblydesignsthatareofsimilarphysicaldesigntotheinitialcoreloading,butarenotlimitedbyanunnecessarymaximumfuelroduraniumweightrequirement.Therequirementofamaximumfuelroduraniumweightisunnecessarybecausechangestothecharacteristicsofthefuelrod(includinguraniumweight)thatcanimpactdesignandsafetycriteriaarespecificallyanalyzedduringthereloadevaluationprocess.Theseevaluations,usingNRCapprovedmethodology,assurethatapplicabledesignandsafetyanalysiscriteriaaremet.Additionally,complianceofthedesignwiththeLimitingSafetySystemSettingsandtheLimitingConditionsforOperationintheTechnicalSpecificationsisdemonstratedduringthereloadevaluationprocess.Therefore,theproposedamendmentwillnotadverselyimpactthesafeoperationofSt.LucieUnit1.TECHNICALDISCUSSIONChangestothecharacteristicsofthefuelrod/assemblythatcanimpactdesigncriteria,safetyanalysiscriteriaorsafetylimitsarespecificallyanalyzedforeachreload,usingNRCapprovedmethodology,toassurethatapplicablecriteriaorlimitsarenotviolated.Theseanalysesalsoassurethatplantoperationwiththe reloadfuelassembliescomplywiththeSafetyLimitsandLimitingConditionsForOperationintheTechnicalSpecifications.AnexampleofthisdesignprocessistheSt.LucieCycle11reloadwhereseveralchangestothefuelroddesignwereincorporatedintothereloadfuelassemblies.Thefuelroddesignchangesconsistedofthefollowing:1.Thepelletdiameterwasincreasedfrom0.370to0.377inches.2.Thepelletdensitywasincreasedfrom944to95%theoreticalUO,density.3.Thecladthicknesswasreducedfrom0.031to0.028inches(identicaltotheinitialcore).4.Thepellet-cladgapwasreducedfrom0.0080to0.0070inches.5.Theactivefuelheightwasincreasedfrom134.1to136.7inches(identicaltotheinitialcore).Thisisaccomplishedbyincreasingthetopnaturaluraniumaxialblanketfrom6.0to8.64inches.6.Theplenumspringlengthwasreducedfrom8.800to5.206inchestoaccommodatetheincreasedactivefuellength.7.Fuelrodheliumfillgaspressurewasincreasedfrom290to330psig.AlthoughthedesignoftheCycle11reloadfuelwassimilarinphysicalcharacteristicstothatofthefuelinitiallyloadedintothereactor,thechangesresultedinanincreasedfuelroduraniumweight(approximately14increaseinthefuelrodweight).Significantaspectsofthechangeswereevaluatedtoshowcompliancewithapplicabledesignandsafetycriteria.Othersecondaryaspectssuchas:structuralimpactonthereactorinternals,vesselsupportsandspentfuelpool,andspentfuelheatload,werequalitativelyevaluatedanddeemedtobeinsignificant.Thekeyresultsandconclusionsarediscussedbelow:a)Thereducedgapwidth,thedecreaseincladdingthickness,theincreaseinfueltheoreticaldensityandtheincreaseinfillgaspressurenecessitatedare-analysis/evaluationoftheLargeBreakandSmallBreakLOCAevents.Theresultsdemonstratedthatall10CFR50.46(b)criteriaweremet.b)TheincreaseintheheatedlengthofthefuelrodanditsimpactontheMinimumDeparturefromNucleateBoilingRatio(MDNBR)wasexplicitlyevaluatedintheThermalMargin/Low PressureandtheDNB/LCO(LimitingConditionForOperation)verificationanalysesforCycle11.TheresultsdemonstratedthatthecurrentsetpointsprovidesufficientmargintoDNB.c)TheimpactofthereductioningapwidthonthehotrodgapconductancethroughoutthecycleanditseffectonAnticipatedOperationalOccurrences(AOO)wasevaluated.EvaluationofthelimitingDNBAOO,LossofFlow,demonstratedthatthereferenceanalysisremainsboundingforCycle11.d)Theimpactofthedesignchangesonthecorephysicsparameterswereexplicitlymodeled.Theresultsdemonstratedthatthekeyparametersmetapplicabledesignandsafetycriteria,andTechnicalSpecifications.Forexample,peaklinearheatrateandradialpeakingfactorvaluesof13.4kw/ftand1.59,respectively,,werecalculated.ThecorrespondingTechnicalSpecificationlimitsare15.0and1.70.Excessshutdownmarginof1406pcmwascalculated.TheModeratorTemperatureCoefficientwascalculatedtobewithintheTechnicalSpecificationlimitsatalltimesduringCycle11operation.e)IntegrityofthenewfuelroddesignduringnormaloperationandAnticipatedOperationalOccurrenceswasconfirmedbyadetailedmechanicalperformanceanalysis.Itwasconcludedthat:themaximumsteady-statecladdingstrainwaswellbelowthe14designlimit,themaximumsteady-statecladdingstressesmettheASMEBoilerandPressureVesselCodeRequirements,thetransientcircumferentialstrainwaswithinthe1%designlimit,thetransientstresscalculatedduringpowerramps(uptothemaximumallowablepeakingfactor)waswithinthe56ksidesignlimit,claddingcreepcollapsewasprecluded,thefuelrodpressureremainedbelowthedesigncriteriaofsystempressureplus800psithroughoutlife,themaximumlocalcladdingoxidationwasbelowthe130micronlimit,thecladdingfatigueusagefactorwasbelowthe0.67designlimit, thefueltemperatureremainedbelowthemeltingtemperatureandthecladtotaluniformstrainremainsbelow14fortheAOOcondition.f)Radiologicalconsequencesforeachlimitingeventwereevaluatedagainst10CFR100criteriaandfoundtobeboundedbytheresultsofpreviousanalysis.Znconclusion,thedeletionofthemaximumrodweightintheDesignFeaturesSection5.3.1oftheTechnicalSpecificationsonFuelAssemblieswillpermitchangesinroduraniumweightwhilemaintainingsimilarityinphysicaldesigntothatoftheinitialcore.AnychangesinthecharacteristicsofthereloadfuelassemblieswillbelimitedtothosedesignsthathavebeenanalyzedusinganNRCapprovedmethodologyandshownbytestsoranalysestocomplywithallapplicabledesignandsafetycriteria.

St.LucieUnit1DocketNo.50-335ProposedLicenseAmendmentAlternativeReuirementsforFuelAssembliesATTACHMENT3DETERMINATIONOFNOSIGNIFICANTHAZARDSCONSIDERATIONvThestandardsusedtoarriveatadeterminationthatarequestforamendmentinvolvesanosignificanthazardsconsiderationareincludedintheCommissionsregulation,10CFR50.92.10CFR50.92statesthatnosignificanthazardsconsiderationsareinvolvediftheoperationofthefacilityinaccordancewiththeproposedamendmentwouldnot(1)involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluatedyor(2)createthepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated;or(3)involveasignificantreductioninamarginofsafety.Eachstandardisdiscussedasfollows:Operationofthefacilityinaccordancewiththeproposedamendmentwouldnotinvolveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated.Theamendmentwillnotincreasetheprobabilityofanaccidentbecauseitdoesnotchangetheplantoperatingmodesortherequirementthatthereloadfuelbesimilarinphysicaldesigntotheinitialcoreloading.Thisrequirementensuresthatthefuelassemblyoutsidedimensionsandinterfacewithcoreinternalsandotherplantequipmentremainthesame.Thisresultsinnochangeinthehandlingandoperationofthefuelassembliesthatwouldincreasetheprobabilityofanaccident.Additionally,theconsequencesofanypreviouslyanalyzedaccidentwillnotbesignificantlyincreasedsinceanychangestothefuelassemblydesignwillcontinuetobeevaluatedusingNRCapprovedmethodologytodemonstratecompliancewithapplicabledesignandsafetycriteria.(2)Useofthemodifiedspecificationwouldnotcreatethepossibilityofanewordifferentkindofaccidentfromanypreviouslyevaluated.Theamendmentwillnotcreatethepossibilityofanewordifferentaccidentnotpreviouslyanalyzed,sincetheoperatingmodesandplantconfigurationwillnotbechangedfromthosepreviouslyanalyzedintheFinalSafetyAnalysisReport.

I fL(3)Useofthemodifiedspecificationwouldnotinvolveasignificantreductioninamarginofsafety.Thisamendmentwillnotreducethemarginofsafetysincetheplantoperatingandsafetylimitswillremainunchanged.AllcycledesignshavebeenandwillcontinuetobeanalyzedusingNRCapprovedmethodstodemonstratethatexistingdesignlimitsandsafetyanalysiscriteriaaremetinadvanceofcycleoperation.Inaddition,theNRChasprovidedexamplesofamendmentsthatareconsiderednotlikelytoinvolvesignificanthazardsconsiderations(48Fed.Reg.at14870).Thisproposedamendmentmatchesexample(iii):"achangeresultingfromanuclearreactorcorereloading,ifnofuelassembliessignificantlydifferentfromthosefoundpreviouslyacceptabletotheNRCforapreviouscoreatthefacilityinquestionareinvolved.ThisassumesthatnosignificantchangesaremadetoacceptancecriteriafortheTechnicalSpecifications,thattheanalyticalmethodsusedtodemonstrateconformancewiththeTechnicalSpecificationsandregulationsarenotsignificantlychanged,andthattheNRChaspreviouslyfoundsuchmethodsacceptable."ThisparticularamendmentforalessrestrictivefuelroduraniumweightmatchesthisexamplesinceTechnicalSpecification5.3.1willcontinuetorequirereloadfuelassemblieswhicharesimilarinphysicaldesignasthatpreviouslyapprovedforSt.LucieUnit1~Whencomparedtothestandardssetin10CFR50.92(c),thisproposedamendmentdoesnotinvolveasignificantsafetyhazardsconsideration.ThisisfurtherverifiedbycomparingthischangewiththeexamplegivenintheFederalRegister,wherein,thisisachangethatwillresultinthereactorcorebeingreloadedwithfuelassemblydesignsthathavebeenanalyzedwithapplicableNRCapprovedmethodologytoverifycompliancewithapplicabledesignandsafetycriteria.Therefore,itisconcludedthatoperationofSt.LucieUnit1inaccordancewiththeproposedamendmentwillnotposeathreattothepublichealthandsafety.Basedontheabove,wehavedeterminedthattheproposedamendmentdoesnot(1)involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated,(2)createtheprobabilityofanewordifferentkindofaccidentfromanypreviouslyevaluated,or(3)involveasignificantreductioninamarginofsafety;andthereforedoesnotinvolveasignificanthazardsconsideration.

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