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)

NFORMATION DISTRIBUTION SEM(RIDS)ACCESSION.

NBR;5507290387 DOC~DATE:85/07/19FACIL':50-.335 St.LuciePlantEUnit1<FloridaAUTHsNAMEAUTHORAFFILIATION HILLIAMSEJ

~N.Florida-Power8LightCo,RECIP,NAME<RECIPIENT AFFILIATION THOMPSONEH

~LEDivisionofLicensing NOTARIZED:

YESPowerLLightCo.DOCKET5000335

SUBJECT:

Application toamendLicenseDPR67<permitting continued operation atratedthermalpowerforspecified periodoftimefollowing droppedcontrolelementassembly.No significant hazardsevaluation encl.DISTRIBUTION CODE:ADOIDCOPIESRECEIVEDiLTRgENCL.]SIZE:2+K"TITLE.:ORSubmittal:

GeneralDistribution NOTES:OL:02/01/76 05000335RECIPIENTIDCODE/NAME NRRORB3BC01.COPIESRECIPIENT LTTRENCLIDCODE/NAME 77COPIESLTTRENCL<INTERNALo ACRS09ELD/HDS2NRR/DLDIRNRR/DL/TSRG NRR/DSI/RAB RGN266101111111ADM/LFMBNRR/DE/MTEB NRR/DL/ORAB NRR/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-85-268OfficeofNuclearReactorRegulation Attention:

Mr.HughL.ThompsonDivisionofLicensing U.S.NuclearRegulatory Commission Washington, D.C.20555

DearMr.Thompson:

Re:St.LucieUnitNo.IDocketNo.50-335ProposedLicenseAmendment MovableControlAssemblies Inaccordance withIOCFR50.90,FloridaPower8LightCompanysubmitsherewitthreesignedoriginals andfortycopiesofarequestto"amendAppendixAofFacilityperaIgLicensesDPR-67.Therequested changewillpermitcontinued operation atRatedThermalPowerforaspecified periodoftimefollowing adroppedControlElementAssembly.

Furthermore, thecurrentactionstatement Cwillbereformulated intonewactionstatements CandH.Thisreformulation willbettercorrelate therequirements forcorrective actioninaTechnical Specification withtheunderlying analytical assumptions theactionstatements aredesignedtoprotect.Anosignificant hazardsevaluation hasbeenperformed asrequiredbyIOCFR50.91and92andisprovided.

Theproposedamendment hasbeenreviewedbytheSt.LuciePlantFacilityReviewGroupandtheFloridaPower&LightCompanyNuclearReviewBoard.Inaccordance withIOCFR50.9I(b)(l),

acopyoftheproposedamendment isbeingforwarded tothestatedesigneefortheStateofFlorida.Inaccordahce withIOCFRI70.2I,acheckisattachedasremittance forthelicenseamendment application feeforSt.LucieUnitI.8507290387 8507i9aoocxosoOoss5PPDR~yt(PEOPLE...

SERVINGPEOPLE JI)K~l'f Page2OfficeofNuclearReactorRegulation Mr.HughL.ThompsonShouldyouhaveanyquestions regarding thissubmittal, pleasefeelfreetocontactuseVerytrulyyours,gCC/~~uJ.W.Williams, Jr.GroupVicePresident NuclearEnergyJWW/RG/cab Attachments cc:Dr.J.NelsonGrace,RegionIIHaroldF.Reis,EsquireLyleE.Jerret,Ph.D,DirectorRadiological HealthServicesDepartment ofHealth&Rehabilitative Servicesl323WinewoodBoulevard Tallahassee, Florida3230I SAFETYEVALUATION ANDDETERMINATION OFNOSIGNIFICANT HAZARDSMODIFICATION TOSTLUCIE1TECHNICAL SPECIFICATION 3/41.3PIntroduction:

TwochangeshavebeenproposedforSt.LucieUnit1Technical Specification 3/4.1.3.ThepurposeofthefirstchangeistopermitUnit1tocontinuetooperateatratedthermalpowerforsomeperiodoftimefollowing aninadvertent singledroppedcontrolelementassemblyCEA.Theintentofthesecondchangeistoreformulate anexistingActionstatement (ActionC)intotwoseparateactionstatements (ActionsCandH)tomoreclearlylinkanyrequiredoperatoractionwiththeapplicable analysisassumptions requiring thataction.ThefirstproposedchangewillpermitSt.LucieUnit1tocontinuetooperateatratedthermalpowerforaperiodoftimefollowing aninadvertent singledroppedCEA.Thisperiodoftimewilldependonthepre-dropvalueoftheintegrated radialpeakingfactor(FR)measuredattheplantduringnormalpowerdistribution surveillances.

The.onlytransient affectedbythisproposedTechnical Specification changeisthesingleCEAdrop.TheCEAdropaccidentisdefinedastheelectrical ormechanical failureoftheCEAdrivemechanism whichopensthecircuitoftheholdingcoilcausingtheCEAtodropintothecore.ThesingleCEAdroptransient isanimportant partofdetermining theplantDNB-related operating space.Initially, theCEAdropeventcausesadecreaseinthereactorpower.Theheatextraction bythesecondary plantremainsessentially constanthowever,causingtheaveragereactorcoolanttemperature todecrease.

Thistemperature

decrease, combinedwiththeassumedendofcyclenegativevalueofthemoderator temperature coefficient, willcausethereactorpowerleveltoreturntoitsinitialpowerlevelwiththedroppedCEAstillremaining inthecore.ThepresenceofthedroppedCEAwillresultinadistorted corepowerdistribution andincreased peakingfactors.InplantssuchasSt.LucieUnit1withanalog-type ReactorProtective Systems,thereisnoneedforaspecifictrip'signalorotherautomatic actiontobegenerated following aninadvertent droppedCEA.Instead,sufficient marginhasbeendesignedintotheplantoperating space,specifically intheDNBLimitingCondition forOperation (LCO),toensureacceptable consequences fortheworstdroppedCEAatanytimeduringcorelife.Additionally>

thisdesignmarginiscomplemented bytheactionoftheReactorProtective Systemtoinhibitautomatic CEAwithdrawal duringaCEAdropevent.ThisfeaturehasbeencreditedintheCEA"dropanalysis.

e'1II ForSt.LucieUnit1,marginwasdesignedintotheDNBLCOthroughtheinputvalueschosenfortheXCOBRA(Reference 1)thermalmarginanalysismodel.A10%greaterinputvalue(1.87)ofFR,afteruncertainties, thantheTechnical Specifidation limitofFR(1.70)wasused.EvenusingthegreaterinputvalueofFR(1.87)inthethermalmarginanalysis, theresulting DNBR'sweregreaterthantheDNBSpecified Acceptable, FuelDesignLimits(SAFDL).Themarginbetweenthepermissible normaloperation limitof1.70(oractuallowermeasuredvalue)andthe1.87thermalmargininputvaluecanbeutilizedasavailable overpower margin(AOPM)forthesingleCEAdropanalysis.

Table1detailsthespecificcycle5&6singleCEAdropresults.FromanalysisresultstheincreaseinassemblypeakFRvaluesfollowing adropped.CEAeventwasseento'eafunctionofthereactivity worthofthedroppedCEAandtheassembly's distancefromthedroppedCEA.BecauseofthisanassemblyotherthantheonewiththecoremaximumFRcanhavealargerpercentincreasethanthecoremaximumFRassembly.

Forcycles5and6themaximumFRincreaseinanon-peripheral assemblywascalculated tobe9.2%ofitsinitial(pre-drop) valueimmediately following thedroppedrodeventand11.7%afteronehour.Peripheral assemblies contained thegreatestpercentage FRincrease.

However,theseassemblies areoflowpowerandarenotlimiting.

Theywerenotconsidered inselecting themaximumFRincrease.

Ascanbeseenfromtheattachedtabulated data,forbothcycles5and6theincreaseinthemaximumcore-wide valueofFRonehourfollowing a'CEAdropislessthan10%.Thismeansthatforcycles5and6ifthebefore-drop FRwasequalto1.70,onehourfollowing theCEAdropthemaximumFRwouldhaveincreased 8.3%toapproximately 1.84.Thisvalueislessthanthe1.87valueusedasinputtogeneratetheDNBLCO,therefore<

theplantcouldremainat100%powerforonehourfollowing theworstcaseCEAdropatanytimeduringcycles5or6.ToassuretheCEAdropresultsfromfuturecycleswillbebounded,Figure3.l-laintheproposedTechnical Specification wasdrawntopermitonly15minutesoffullpoweroperation whenthepre-dropvalueofFRequals1.70.Asthepre-dropvalueofFRdecreases below1.70,thetimeSt.LucieUnit1mayremainatfullpowerafteradropincreases uptoamaximumofonehourascanbeseeninFigure3.1-1a.Fromareactoroperation standpoint, valuesofFR>1.67arenotanticipated tooccur.TofurtherassureFigure'.l-la remainsbounding, theincreaseinthecoremaximumFRfortheCEAdroptransient willbeanalyzedforeachfuturecycle.Asstatedabove,theproposedTechnical "Specification changeattachedrequiresthemisaligned CEAberealigned withtherestofitsbankwithinaspecified amountoftimedepending onthepre-dropmeasuredFR.IftheCEAcannotberealigned withinthistimeperiod,reactorpowermustbereducedtoC70%ofratedpower.Withinthetimeconstraints giveninFigure3.1-la<

theanalysispresented inthisreportdemonstrates thatthepeaQingfactorincreaseduringtheonehourperiodwillnotexceedthatutilizedinthesafetyanalysisforthedro'ppedCEAevent.ThesecondproposedchangetoSpecification 3/4.1.3consistsofthereformulation of.ActionStatement CintotwoActionStatements, CandH.Thischangewillbettercorrelate therequirements forcorrective actioninaTechnical Specification withtheunderlying analytical assumptions theactionstatements aredesignedtoprotect.Thereasonforthisactionstatement istoassurethattheassumptions madeinthesafetyanalysisregarding thecorepowerdistribution (specifically axialshapeanalysis) duringthecycledepletion boundthepowerdistributions seeninthecoreduringactualoperation.

Theseassumedpowerdistributioz areusedinseveralplantsafetyanalysisandarealsousedingenerating theUnit'1operating setpoints.

Validityoftheseassumptions canbeassuredbylimiting, asisdoneinSpecification 3.1.3.6,thetimedurationoperation maycontinuewithCEAsinserted'eyond theLongTermInsertion Limits(LTIL).Specification 3.1.3.6limitsthisinsertion tolessthanorequalto14EFPDperyear.Thistimelimit,whichisapplicable toSpecification 3/4.1.3,willensurethepowerdistribution asactuallydepletedinthecorecloselyapproximates anunroddedpowerdistribution depletion.

Ifoperation beyond.theLTILwaspermitted atratedthermalpowerinexcessof14dayspercalendaryear,theresulting cyclepowerdistribution wouldbegintosignificantly deviatefromtheunroddeddistribution assumed.Analysisofthiscondition couldrequirethemodification ofplanttransient analysis.

WhenCEAsarepositioned withintheiralignment requirements andatawithdrawn positiongreaterthantheLTILasiscoveredbyActionCofSpecification 3/4.1.3,thentheresulting powerandburnupdistributions willremainboundedbythepowerdistributior usedforplanttransient andsetpointanalysisindependent ofthelengthoftimetheCEAsremaininserted.

Thisisbecausetheoverallperturbation ofthepowerdistribution fromtheAROpowershapeduetothisamountofCEAinsertion issmall.Asnotedabove,St.LucieUnit1proposestorecognize thedistinctions insafetyanalysisrequirements outlinedabovebyreconstructing thepresentactionstatement intotwodifferent actionstatements; onewithapplicability whenCEAsareabovetheLTILandaseparateonewhenCEAsareinsertedbeyondtheLTIL.Thisseparation willaidoperations personnel tobetterunderstand theunderlying technical basisofeachspecification andactionstatement and'itwillaidinthestandardization ofspecifications betweenSt.LucieUnits1and2.Nochangesinsafetyanalysisresultsorinputarerequiredasaresultofthisseparation ortheadditionofFigure3.1-la.Therefore, asrequiredbylOCFR50.92(c)(1),

theproposedchangestoSpecificatia 3/4.1.3donotresultinanincreaseintheprobabil'ity

'orconsequenc ofanyaccidentpreviously evaluated becausenochangeinanalysisinputorassumptions wasrequiredforanytransient.

Acceptable results,willcontinuetobeshownforallpreviously analyzedtransients.

fi 1

TheproposedchangestaSt.LucieTechnical Specification 3/4,1,3donotcreatethepossibility ofnewordifferent typeofaccidentfrom'anyaccidentpreviously evaluated becauseneithertheconfiguration oftheplantnoritsmodeofroperation havebeenmodified.

Becausenochangeswillbemadetothephysicalplantoritsmodeofoperation asaresultofthisTechnical Specification change,thereisnoincreaseinthepossibility ofanewordifferent typeoiaccidentasdiscussed in10CFR50.92(c)(2).

TheproposedchangestotheSt.Lucie1CEAPositionTechnical Specification willnot,resultinanyreduction inthemarginofsafetyasdiscussed in10CFR50.92(c)(3) becausenoinputstonorresultsfromplant'safety analysisrequirechangeormodifications.

Therequiredoverpower marginforeachtransient analyzedforSt.Lucie1iscompletely unaffected bythisproposedchangetherefore, thedifference betweenreactorsafetylimitsandtheresultsofthe'safety

analysis, whichisrepresentative ofthemarginofsafety,isunchanged.

Basedontheinformation presented above,FloridaPower6LightCompanyhasconcluded thattheproposedchangetotheSt.LucieUnit1Technical Specifications doesnotconstitute anunreviewed safetyissueorasignificant hazardtothehealthandsafetyofthepublicasdiscussed in10CFRS0.92(c).

PReference I:N.F.FaunaandT.W.Fatten,XCOBRA-IIIC:

A~ComuterCodetoDetermine theDistribution ofCoolantXN-NF-21(P

),Rev;2,September 1982.

~~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)IncreaseinCoreMaximumFRimmediately following CEAdropb)IncreaseinCoreMaximumFR1hourfollowing CEAdropc)MaximumincreaseinFRanywherewithinthecoreimmediately following dropd)MaximumincreaseinFRanywhereinthecore1hourfollowing CEAdrop