ML17216A252

Application to Amend License DPR-67,permitting Continued Operation at Rated Thermal Power for Specified Period of Time Following Dropped Control Element Assembly.No Significant Hazards Evaluation Encl

ML17216A252
Person / Time
Site:	Saint Lucie
Issue date:	07/19/1985
From:	WILLIAMS J W FLORIDA POWER & LIGHT CO.
To:	THOMPSON H L Office of Nuclear Reactor Regulation
Shared Package
ML17216A253	List: ML17216A252 ML17216A255
References
L-85-268, NUDOCS 8507290387
Download: ML17216A252 (12)

Text

REGULATOR)NFORMATIONDISTRIBUTIONSEM(RIDS)ACCESSION.NBR;5507290387DOC~DATE:85/07/19FACIL':50-.335St.LuciePlantEUnit1<FloridaAUTHsNAMEAUTHORAFFILIATIONHILLIAMSEJ~N.Florida-Power8LightCo,RECIP,NAME<RECIPIENTAFFILIATIONTHOMPSONEH~LEDivisionofLicensingNOTARIZED:YESPowerLLightCo.DOCKET5000335

SUBJECT:

ApplicationtoamendLicenseDPR67<permittingcontinuedoperationatratedthermalpowerforspecifiedperiodoftimefollowingdroppedcontrolelementassembly.Nosignificanthazardsevaluationencl.DISTRIBUTIONCODE:ADOIDCOPIESRECEIVEDiLTRgENCL.]SIZE:2+K"TITLE.:ORSubmittal:GeneralDistributionNOTES:OL:02/01/7605000335RECIPIENTIDCODE/NAMENRRORB3BC01.COPIESRECIPIENTLTTRENCLIDCODE/NAME77COPIESLTTRENCL<INTERNALoACRS09ELD/HDS2NRR/DLDIRNRR/DL/TSRGNRR/DSI/RABRGN266101111111ADM/LFMBNRR/DE/MTEBNRR/DL/ORABNRR/DSI/METB04101110111EXTERNAL;2QXLPDRNSIC0305111111EG5GBRUSKEgSNRCPDR02TOTALNUMBEROFCOPIESREQUIRED:LTTR28ENCL25 IIlfI~Itk,fPrf~lf'lrCktfI>>'kfl<1+Iffr(~,I,I.fkklf>rIttkf'klIr't.III,If'.I))'-<<kkI~Jf)klIJJ.a.'IilgJ'lfl>II,CI(JC)(11CkHl'CIIlf)W'fkfIJPI'C4I~IkfJC1flk"t1ftf')<<k*I~'IIktIF,ff~Ir~f~Ifpft"pl)IfW'fr1Jf<<lfkf'Ia~,)fItIf,'1~'IICfttI0fIr~AsIffkqrIeIICI":IlqI.>kkTf.IWf~llfJkI>ffkffkI$kJrf;~'fIIJf,'JIIlIa/fIII]IX"llIE>lf"k<kl~l$"kI'tkJ~kk$f'rk~kk4~".J>I-I>If1lCIIkft'llIJ POX14000,JUNOBEACH,FL33408FLORIDAPOWER&LIGHTCOMPANYPAL191885L-85-268OfficeofNuclearReactorRegulationAttention:Mr.HughL.ThompsonDivisionofLicensingU.S.NuclearRegulatoryCommissionWashington,D.C.20555

DearMr.Thompson:

Re:St.LucieUnitNo.IDocketNo.50-335ProposedLicenseAmendmentMovableControlAssembliesInaccordancewithIOCFR50.90,FloridaPower8LightCompanysubmitsherewitthreesignedoriginalsandfortycopiesofarequestto"amendAppendixAofFacilityperaIgLicensesDPR-67.TherequestedchangewillpermitcontinuedoperationatRatedThermalPowerforaspecifiedperiodoftimefollowingadroppedControlElementAssembly.Furthermore,thecurrentactionstatementCwillbereformulatedintonewactionstatementsCandH.ThisreformulationwillbettercorrelatetherequirementsforcorrectiveactioninaTechnicalSpecificationwiththeunderlyinganalyticalassumptionstheactionstatementsaredesignedtoprotect.AnosignificanthazardsevaluationhasbeenperformedasrequiredbyIOCFR50.91and92andisprovided.TheproposedamendmenthasbeenreviewedbytheSt.LuciePlantFacilityReviewGroupandtheFloridaPower&LightCompanyNuclearReviewBoard.InaccordancewithIOCFR50.9I(b)(l),acopyoftheproposedamendmentisbeingforwardedtothestatedesigneefortheStateofFlorida.InaccordahcewithIOCFRI70.2I,acheckisattachedasremittanceforthelicenseamendmentapplicationfeeforSt.LucieUnitI.85072903878507i9aoocxosoOoss5PPDR~yt(PEOPLE...SERVINGPEOPLE JI)K~l'f Page2OfficeofNuclearReactorRegulationMr.HughL.ThompsonShouldyouhaveanyquestionsregardingthissubmittal,pleasefeelfreetocontactuseVerytrulyyours,gCC/~~uJ.W.Williams,Jr.GroupVicePresidentNuclearEnergyJWW/RG/cabAttachmentscc:Dr.J.NelsonGrace,RegionIIHaroldF.Reis,EsquireLyleE.Jerret,Ph.D,DirectorRadiologicalHealthServicesDepartmentofHealth&RehabilitativeServicesl323WinewoodBoulevardTallahassee,Florida3230I SAFETYEVALUATIONANDDETERMINATIONOFNOSIGNIFICANTHAZARDSMODIFICATIONTOSTLUCIE1TECHNICALSPECIFICATION3/41.3PIntroduction:TwochangeshavebeenproposedforSt.LucieUnit1TechnicalSpecification3/4.1.3.ThepurposeofthefirstchangeistopermitUnit1tocontinuetooperateatratedthermalpowerforsomeperiodoftimefollowinganinadvertentsingledroppedcontrolelementassemblyCEA.TheintentofthesecondchangeistoreformulateanexistingActionstatement(ActionC)intotwoseparateactionstatements(ActionsCandH)tomoreclearlylinkanyrequiredoperatoractionwiththeapplicableanalysisassumptionsrequiringthataction.ThefirstproposedchangewillpermitSt.LucieUnit1tocontinuetooperateatratedthermalpowerforaperiodoftimefollowinganinadvertentsingledroppedCEA.Thisperiodoftimewilldependonthepre-dropvalueoftheintegratedradialpeakingfactor(FR)measuredattheplantduringnormalpowerdistributionsurveillances.The.onlytransientaffectedbythisproposedTechnicalSpecificationchangeisthesingleCEAdrop.TheCEAdropaccidentisdefinedastheelectricalormechanicalfailureoftheCEAdrivemechanismwhichopensthecircuitoftheholdingcoilcausingtheCEAtodropintothecore.ThesingleCEAdroptransientisanimportantpartofdeterminingtheplantDNB-relatedoperatingspace.Initially,theCEAdropeventcausesadecreaseinthereactorpower.Theheatextractionbythesecondaryplantremainsessentiallyconstanthowever,causingtheaveragereactorcoolanttemperaturetodecrease.Thistemperaturedecrease,combinedwiththeassumedendofcyclenegativevalueofthemoderatortemperaturecoefficient,willcausethereactorpowerleveltoreturntoitsinitialpowerlevelwiththedroppedCEAstillremaininginthecore.ThepresenceofthedroppedCEAwillresultinadistortedcorepowerdistributionandincreasedpeakingfactors.InplantssuchasSt.LucieUnit1withanalog-typeReactorProtectiveSystems,thereisnoneedforaspecifictrip'signalorotherautomaticactiontobegeneratedfollowinganinadvertentdroppedCEA.Instead,sufficientmarginhasbeendesignedintotheplantoperatingspace,specificallyintheDNBLimitingConditionforOperation(LCO),toensureacceptableconsequencesfortheworstdroppedCEAatanytimeduringcorelife.Additionally>thisdesignmarginiscomplementedbytheactionoftheReactorProtectiveSystemtoinhibitautomaticCEAwithdrawalduringaCEAdropevent.ThisfeaturehasbeencreditedintheCEA"dropanalysis.

e'1II ForSt.LucieUnit1,marginwasdesignedintotheDNBLCOthroughtheinputvalueschosenfortheXCOBRA(Reference1)thermalmarginanalysismodel.A10%greaterinputvalue(1.87)ofFR,afteruncertainties,thantheTechnicalSpecifidationlimitofFR(1.70)wasused.EvenusingthegreaterinputvalueofFR(1.87)inthethermalmarginanalysis,theresultingDNBR'sweregreaterthantheDNBSpecifiedAcceptable,FuelDesignLimits(SAFDL).Themarginbetweenthepermissiblenormaloperationlimitof1.70(oractuallowermeasuredvalue)andthe1.87thermalmargininputvaluecanbeutilizedasavailableoverpowermargin(AOPM)forthesingleCEAdropanalysis.Table1detailsthespecificcycle5&6singleCEAdropresults.FromanalysisresultstheincreaseinassemblypeakFRvaluesfollowingadropped.CEAeventwasseento'eafunctionofthereactivityworthofthedroppedCEAandtheassembly'sdistancefromthedroppedCEA.BecauseofthisanassemblyotherthantheonewiththecoremaximumFRcanhavealargerpercentincreasethanthecoremaximumFRassembly.Forcycles5and6themaximumFRincreaseinanon-peripheralassemblywascalculatedtobe9.2%ofitsinitial(pre-drop)valueimmediatelyfollowingthedroppedrodeventand11.7%afteronehour.PeripheralassembliescontainedthegreatestpercentageFRincrease.However,theseassembliesareoflowpowerandarenotlimiting.TheywerenotconsideredinselectingthemaximumFRincrease.Ascanbeseenfromtheattachedtabulateddata,forbothcycles5and6theincreaseinthemaximumcore-widevalueofFRonehourfollowinga'CEAdropislessthan10%.Thismeansthatforcycles5and6ifthebefore-dropFRwasequalto1.70,onehourfollowingtheCEAdropthemaximumFRwouldhaveincreased8.3%toapproximately1.84.Thisvalueislessthanthe1.87valueusedasinputtogeneratetheDNBLCO,therefore<theplantcouldremainat100%powerforonehourfollowingtheworstcaseCEAdropatanytimeduringcycles5or6.ToassuretheCEAdropresultsfromfuturecycleswillbebounded,Figure3.l-laintheproposedTechnicalSpecificationwasdrawntopermitonly15minutesoffullpoweroperationwhenthepre-dropvalueofFRequals1.70.Asthepre-dropvalueofFRdecreasesbelow1.70,thetimeSt.LucieUnit1mayremainatfullpowerafteradropincreasesuptoamaximumofonehourascanbeseeninFigure3.1-1a.Fromareactoroperationstandpoint,valuesofFR>1.67arenotanticipatedtooccur.TofurtherassureFigure'.l-laremainsbounding,theincreaseinthecoremaximumFRfortheCEAdroptransientwillbeanalyzedforeachfuturecycle.Asstatedabove,theproposedTechnical"SpecificationchangeattachedrequiresthemisalignedCEAberealignedwiththerestofitsbankwithinaspecifiedamountoftimedependingonthepre-dropmeasuredFR.IftheCEAcannotberealignedwithinthistimeperiod,reactorpowermustbereducedtoC70%ofratedpower.WithinthetimeconstraintsgiveninFigure3.1-la<

theanalysispresentedinthisreportdemonstratesthatthepeaQingfactorincreaseduringtheonehourperiodwillnotexceedthatutilizedinthesafetyanalysisforthedro'ppedCEAevent.ThesecondproposedchangetoSpecification3/4.1.3consistsofthereformulationof.ActionStatementCintotwoActionStatements,CandH.ThischangewillbettercorrelatetherequirementsforcorrectiveactioninaTechnicalSpecificationwiththeunderlyinganalyticalassumptionstheactionstatementsaredesignedtoprotect.Thereasonforthisactionstatementistoassurethattheassumptionsmadeinthesafetyanalysisregardingthecorepowerdistribution(specificallyaxialshapeanalysis)duringthecycledepletionboundthepowerdistributionsseeninthecoreduringactualoperation.TheseassumedpowerdistributiozareusedinseveralplantsafetyanalysisandarealsousedingeneratingtheUnit'1operatingsetpoints.Validityoftheseassumptionscanbeassuredbylimiting,asisdoneinSpecification3.1.3.6,thetimedurationoperationmaycontinuewithCEAsinserted'eyondtheLongTermInsertionLimits(LTIL).Specification3.1.3.6limitsthisinsertiontolessthanorequalto14EFPDperyear.Thistimelimit,whichisapplicabletoSpecification3/4.1.3,willensurethepowerdistributionasactuallydepletedinthecorecloselyapproximatesanunroddedpowerdistributiondepletion.Ifoperationbeyond.theLTILwaspermittedatratedthermalpowerinexcessof14dayspercalendaryear,theresultingcyclepowerdistributionwouldbegintosignificantlydeviatefromtheunroddeddistributionassumed.Analysisofthisconditioncouldrequirethemodificationofplanttransientanalysis.WhenCEAsarepositionedwithintheiralignmentrequirementsandatawithdrawnpositiongreaterthantheLTILasiscoveredbyActionCofSpecification3/4.1.3,thentheresultingpowerandburnupdistributionswillremainboundedbythepowerdistributiorusedforplanttransientandsetpointanalysisindependentofthelengthoftimetheCEAsremaininserted.ThisisbecausetheoverallperturbationofthepowerdistributionfromtheAROpowershapeduetothisamountofCEAinsertionissmall.Asnotedabove,St.LucieUnit1proposestorecognizethedistinctionsinsafetyanalysisrequirementsoutlinedabovebyreconstructingthepresentactionstatementintotwodifferentactionstatements;onewithapplicabilitywhenCEAsareabovetheLTILandaseparateonewhenCEAsareinsertedbeyondtheLTIL.Thisseparationwillaidoperationspersonneltobetterunderstandtheunderlyingtechnicalbasisofeachspecificationandactionstatementand'itwillaidinthestandardizationofspecificationsbetweenSt.LucieUnits1and2.NochangesinsafetyanalysisresultsorinputarerequiredasaresultofthisseparationortheadditionofFigure3.1-la.Therefore,asrequiredbylOCFR50.92(c)(1),theproposedchangestoSpecificatia3/4.1.3donotresultinanincreaseintheprobabil'ity'orconsequencofanyaccidentpreviouslyevaluatedbecausenochangeinanalysisinputorassumptionswasrequiredforanytransient.Acceptableresults,willcontinuetobeshownforallpreviouslyanalyzedtransients.fi 1

TheproposedchangestaSt.LucieTechnicalSpecification3/4,1,3donotcreatethepossibilityofnewordifferenttypeofaccidentfrom'anyaccidentpreviouslyevaluatedbecauseneithertheconfigurationoftheplantnoritsmodeofroperationhavebeenmodified.BecausenochangeswillbemadetothephysicalplantoritsmodeofoperationasaresultofthisTechnicalSpecificationchange,thereisnoincreaseinthepossibilityofanewordifferenttypeoiaccidentasdiscussedin10CFR50.92(c)(2).TheproposedchangestotheSt.Lucie1CEAPositionTechnicalSpecificationwillnot,resultinanyreductioninthemarginofsafetyasdiscussedin10CFR50.92(c)(3)becausenoinputstonorresultsfromplant'safetyanalysisrequirechangeormodifications.TherequiredoverpowermarginforeachtransientanalyzedforSt.Lucie1iscompletelyunaffectedbythisproposedchangetherefore,thedifferencebetweenreactorsafetylimitsandtheresultsofthe'safetyanalysis,whichisrepresentativeofthemarginofsafety,isunchanged.Basedontheinformationpresentedabove,FloridaPower6LightCompanyhasconcludedthattheproposedchangetotheSt.LucieUnit1TechnicalSpecificationsdoesnotconstituteanunreviewedsafetyissueorasignificanthazardtothehealthandsafetyofthepublicasdiscussedin10CFRS0.92(c).PReferenceI:N.F.FaunaandT.W.Fatten,XCOBRA-IIIC:A~ComuterCodetoDeterminetheDistributionofCoolantXN-NF-21(P),Rev;2,September1982.

~~iTABLE1ST.XUCIEUNIT1INCREASEINFRVERSUSTIMEFORCYCLE5AND6CEADROPANALYSISdPa)l4BOC54.8%EOCS6.0%BOC66.3%EOC66.5%b)gc)Md)6.8%9.2%11.7%7.2'%.5%7'%8.3%9.7%-10.6%8.3%8.0%10.2%a)IncreaseinCoreMaximumFRimmediatelyfollowingCEAdropb)IncreaseinCoreMaximumFR1hourfollowingCEAdropc)MaximumincreaseinFRanywherewithinthecoreimmediatelyfollowingdropd)MaximumincreaseinFRanywhereinthecore1hourfollowingCEAdrop