ML17213B033

Proposed Tech Spec Revising Linear Heat Rate Prior to Unit Restart Following Upcoming Refueling Outage

ML17213B033
Person / Time
Site:	Saint Lucie
Issue date:	02/08/1983
From:	FLORIDA POWER & LIGHT CO.
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ML17213B032	List: ML17213B031 ML17213B033
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NUDOCS 8302150008
Download: ML17213B033 (17)

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POWERDISTRIBUTION LIMITSSURVEILLANCE REQUIREMENTS continued c.Verifying thattheAXIALSHAPEINDEXismaintained withintheallowable limitsofFigure3.2-2,where100percentofmaximumallowable powerrepresents themaximumTHERMALPOWERallowedbythefollowing expression:

MxNwhere:1.Misthemaximumallowable THERMALPOWERlevelfortheexistingReactorCoolantPumpcombination.

2.Nisthemaximumallowable fractionofRATEDTHERMALPOWERasdetermined bytheFxcurveofFigure3.2-3..4.2.1.4IncoreDetectorMonitoring Systems-Theincoredetectormonitorsystemmaybeusedformonitoring thecorepowerdistribution byverifyingthattheincoredetectorLocalPowerDensityalarms:a.Areadjustedtosatisfytherequirements ofthecorepowerdistribution mapwhichshallbeupdatedatleastonceper31daysofaccumulated operation inMODE1.b.HavetheiralarmsetpointadjustedtolessthanorequaltothelimitsshownonFigure3.2-1whenthefollowing factorsareappropriately includedinthesettingofthesealarms:.1.Ameasurement calculational uncertainty factorof1.07*,2.Anengineering uncertainty factorof1.03,3.Alinearheatrateuncertainty factorof1.01duetoaxialfueldensification andthermalexpansion, and4.ATHERMALPOWERmeasurement uncertainty factorof1.02.*Anuncertainty factorof1.10applieswheninLOADFOLLOWOPERATION.

gIfthecoresystembecomesinoperable, reducepowertoMxNwithin4hoursandmonitorlinearheatrateinaccordance withSpecification 4.2.1.ST.LUCIE-UNIT13/42-2Amendment No.

/~~~'3/4.2:~PONER0ISTRIBUTIONLINITSBASES3/4.2.1LINEARHEATRATEThelimitation oflinearheatrateensuresthatintheeventofaLOCA,thepeaktemperature ofthefuelcladdingwillnotexceed2200'F.Eitherofthetwocorepowerdistribution monitoring systems,theExcoreDetectorMonitoring SystemandtheIncoreDetectorthonitoring System,provideadequatemonitoring ofthecorepowerdistribution andarecapableofverifying thatthelinearheatratedoesnotexceeditslimits.TheExcoreDetectorMonitoring Systemperformsthisfunctionbycontinuously monitoring theAXIALSHAPEINDEXwiththeOPERABLEquadrantsymmetric excoreneutron.fluxdetectors andverifying thattheAXIALSHAPEINDEXismaintained withintheallowable limitsofFigure3.2-2.Inconjuction withtheuseoftheexcoremonitoring systemandinestablishing theAXIALSHAPEINDEXlimits,thefollowing assumptions aremade:1)theCEAinsertion limitsofSpecifications 3.1.3.5and3.1.3.6aresatisfied, 2)theAZIMUTHAL POllERTILTrestrictions ofSpecification3.2.4aresatisfied, and3)theTOTALPLANARRADIALPEAKINGFACTORdoesnotexceedthelimitsofSpecification 3.2.2.TheIncoreDetectortlonitoring Systemcontinuously providesadirectmeasureofthepeakingfactorsandthealarmswhichnavebeenestablished fortheindividual incoredetectorsegmentsensurethatthepeaklinearheatrateswillb.maintained withintheallowable limitsofFigure3.2-1.Thesetpoints forthesea'farmsincludeallowances, setintheconservative directions, for1)ameasurement-cal culational uncertainty factorof1.07*,2)anengineering unceit.aintyfactorof1.03,3)anallowance of1.01foraxialfueldensification andthermalexpansion, and4)aTHERMALPOWERmeasurement uncertainty factorof1.02.3/4.2.2,3/4.2.3and3/4.2.4TOTALPLANARANDINTEGRATED RADIALPEAKINGFACTORSFyANDFrANDAZIMUTHAL POWERTILTTqThelimitation onFTandTareprovidedtoensurethattneassumptions usedintheanalysisforBtablisfling theLinearHeatRateandLocalPowerDensity-HighLCOsandLSSSsetpoints remainvalidduringoperation atthevariousallowable CEAgroupinsertion limits.Thelimitations onFTrandTqareprovidedtoensurethattheassumptions

~Anuncertainty factorof1.10applieswheninLOADFOLLOWOPERATION.

ST.LUCIE-UNIT183/42-1 O.

2.1SAFETYLIMITSBASES2.1.1REACTORCORETherestrictions ofthissafetylimitpreventoverheating ofthefuelcladdingandpossiblecladdingperforation whichwouldresultinthereleaseoffissionproductstothereactorcoolant.Overheating ofthefuelisprevented bymaintaining thesteadystatepeaklinearheatratebelowthelevelatwhichcenterline fuelmeltingwilloccur.Overheating ofthefuelcladdingisprevented byrestricting fueloperation towithi'nthenucleateboilingregimewheretheheattransfercoefficient islargeandthecladdingsurfacetemperature isslightlyabovethecoolantsaturation temperature.

Operation abovetheupperboundaryofthenucleateboilingregimecouldresultinexcessive claddingtemperatures becauseoftheonsetofdeparture frcmnucleateboiling(DNB)andtheresultant sharpreduction inheattransfercoefficient.

DNBisnotadirectlymeasurableparameter duringoperation andtherefore THERMALPOWERandReactorCoolantTemperatur eandPressurehavebeenrelatedtoDNBthroughtheExxonXNBcorrelation.

TheXNBDNBcorrelation hasbeendeveloped topredicttheDNBfluxandthelocationofDNBforaxiallyuniformandnon-uniform heatfluxdistributions.

ThelocalDNBheatfluxration,DNBR,definedastheratiooftheheatfluxthatwouldcauseDNBataparticular corelocationtothelocalheatflux,isindicative ofthemargintoDNB.TheminimumvalueoftheDNBRduringsteadystateoperation, normaloperational transients, andanticipated transients islimitedto1.22usingtheXNBDNBRcorrelation.

Thisvaluecorresponds toa95percentprobability ata95percentconfidence levelthatDNBwillnotoccurandischosenasanappropriate margintoDNBforalloperating conditions.

ThecurvesofFigure2.1-1showthelociofpointsofTHERMALPOWER,ReactorCoolantSystempressureandmaximumcoldlegtemperatur e'ithfourReactorCoolantPumpsoperating forwhichtheminimumDNBRisnolessthantheDNBRlimitforthefamilyofaxialshapesandcorresponding radialpeaksshowninFigureB2.1-1.ThelimitsinFigure2.1-1werecalculated forreactorcoolantinlettemperatures lessthanorequalto580'F.Thedashedlineof580'Fcoolantinlettemperature isnotasafetylimit;however,operation above580'Fisnotpossiblebecauseoftheactuation ofthemainsteamlinesafetyvalveswhichlimitthemaximumvalueofreactorinlettempratur e.Reactoroperation atTHERMALPOWERlevelshigherthan112$ofRATEDTHERMALPOWERisprohibited bythehighpowerleveltripsetpointspecified inTable2.1-1.Theareaofsafeoperation isbelowandtotheleftoftheselines.ST.LUCIEUNIT1B2-1 SAFETYLIMITSBASESTheconditions fortheThermalMargi'nSafetyLimitcurvesinFigure2.1-1tobevalidareshownonthefigure.Thereactorprotective systeminccmbination withtheLimitingConditions forOperation, isdesignedtopreventanyanticipated combination oftransient conditions forreactorcoolantsystemtemperature,

pressure, andthermalpowerlevelthatwouldresultinaDNBRoflessthantheDNBRlimitandprecludethe)existenceofflowinstabilities.

2.1.2REACTORCOOLANTSYSTEMPRESSURETherestriction ofthisSafetyLimitprotectstheintegrity oftheReactorCoolantSystemforoverpressurization andtherebypreventsthereleaseofradionuclides contained inthereactorcoolantfromreachingthecontainment atmosphere.

Thereactorpressurevesselandpressurizer aredesignedtoSectionIIIoftheASMECodeforNuclearPowerPlantcomponents whichpermitsamaximumtransient pressureof11(g(2750psia)ofdesignpressure.

TheReactorCoolantSystempiping,valvesandfittings, aredesignedtoANSIB31.7,ClassIwhichpermitsamaximumtransient pressureoflit@(2750psia)ofccmponent designpressure.

TheSafetyLimitof2750psiaistherefore consistent withthedesigncriteriaandassociated coderequiranents.

TheentireReactorCool.antSystemishydrotested at3125psiatodemonstrate integrity priortoinitialoperation.

ST.LUCIE-UNIT1B2-3Amendment No.

2.2LIMITINGSAFETYSYSTEMSETTINGSBASESReactorCoolantFlow-Low(Continued) reactorcoolantpumpsaretakenoutofservice.Thelow-flowtripsetpoints andAllowable Valuesforthevariousreactorcoolantpumpcombinations havebeenderivedinconsideration ofinstrument errorsandresponsetimesofequipment involvedtomaintaintheDNBRabovetheDNBRlimitundernormaloperation andexpectedtransients.

Forreactoroperation withonlytwoorthreereactorcoolantpumpsoperating, theReactorCoolantFlow-Lowtripsetpoints, thePowerLevel-High tripsetpoints, andtheThermalMargin/Low Pressuretripsetpoints areautomatically changedwhenthepumpcondition selectorswitchismanuallysettothedesiredtwo-orthree-pump position.

Changingthesetripsetpoints duringtwoandthreepumpoperation preventstheminimum.valueofDNBRfrcmgoingbelowtheDNBRlimitduringnormaloperational transients andanticipated transients whenonlytwoorthreereactorcoolantpumpsareoperating.

PressurizerPressure-High ThePressurizer Pressure-High trip,backedupbythepressurizer codesafetyvalvesandmainsteamlinesafetyvalves,providesreactorcoolantsystemprotection againstoverpressurization intheeventoflossofloadwithoutreactortrip.Thistrip~'ssetpointis100psibelowthenaninalliftsetting(2500psia)ofthepressurizer codesafetyvalvesanditsconcurrent operation withthepower-operated reliefvalvesavoidstheundesirable operation ofthepressurizer codesafetyvalves.Contairment Pressure-High TheContairment Pressure-High tripprovidesassurance thatareactortripisinitiated concurrently withasafetyinjection.

SteamGenerator Pressure-Low TheSteamGenerator Pressure-Low tripprovidesprotection againstanexcessive rateofheatextraction fromthesteamgenerators andsubsequent cooldownofthereactorcoolant.Thesettingof600psiaissufficiently belowthefull-load operating pointof800psigsoasnotST.LUCIE-,UNIT1B2-.5Anendment No.

LIMITINGSAFETYSYSTEMSETTINGSBASESThermalMarin/LowPressureTheThermalMargin/LowPressuretripisprovidedtopreventoperation whentheDNBRislessthantheDNBRlimit.Thetripisinitiated wheneverthereactorcoolantsystempressuresignaldropsbeloweither1887psiaoraccmputedvalueasdescribed below,whichever is'igher.

TheccmputedvalueisafunctionofthehigherofhTpowerorneutronpower,reactorinlettemperature, thenumberofreactorcoolantpumpsoperating andtheAXIALSHAPEINDEX.Theminimumvalueofreactorcoolantflowrate,themaximumAXIMUTHAL POWERTILTandthemaximumCEAdeviation permitted forcontinuous operation areassumedinthegeneration ofthistripfunction.'n

addition, CEAgroupsequencing inaccordance withSpecifications 3.1.3.5and3.1.3.6isassumed.Finally,themaximuminsertion ofCEAbankswhichcanoccurduringanyanticipated operational occurrence priortoaPowerLevel-High tripisassumed.TheThermalMargin/Low Pressuretripsetpoints includeappropriateallowances forequipment responsetime,calculational andmeasurement uncertainties, andprocessing error.Afurtherallowance of30psiaisincludedtocompensate forthetimedelayassociated withproviding effective termination oftheoccurrencethatexhib1tsthemostrapiddecreaseinmargintotheDNBRlimit.Asymmetric SteamGenerator TransientProtective TripFunctionASGTPTFTheASGTPTFconsistsofSteamGenerator pressureinputstotheTM/LPcalculator, whichcausesareactortripwhenthedifference inpressurebetweenthetwosteamgenerators exceedsthetripsetpoint.

TheASGTPTFisdesignedtoprovideareactortripforthoseeventsassociated withsecondary systanmalfunctions whichresultinasymmetric primaryloopcoolanttemperatures.

Themostlimitingeventisthelossofloadtoonesteamgenerator causedbyasinglemainsteamisolation valveclosure.Theequipment tripsetpointandallowable valuesarecalculated toaccountforinstrument uncertainties, andwillensureatripatorbeforereachingtheanalysissetpoint.

ST.LUCIE-UNIT1B2-7

POWERDISTRIBUTIONLIMITSBASESusedintheanalysisestablishing theDNBMarginLCO,andThermalMargin/Low PressureLSSSsetpoints remainvalidduringoperation atthevariousal1owableCEAgroupinsertion Limits.IfF,ForTexceedxy'theirbasiclimitations, operation maycontinueundertheadditional restrictions imposedbytheACTIONstatements sincetheseadditional restrictions provideadequateprovisions toassurethattheassumptions usedinestablishing theLinearHeatRate,ThermalMargin/Low PressureandLocalPowerDensity-HighLCOsandLSSSsetpoints remainvalid.AnAZIMUTHAL PO'WERTILT)0.10isnotexpectedandifitshouldoccur,subsequent operationwouldberestricted toonlythoseoperations requiredtoidentifythecauseofthisunexpected tilt.ThevalueofTthatmustbeusedintheequationF=F(1+T)qandF=F(1,+T)isthemeasuredtilt.rr'Thesurveillance requirements forverifying thatF,FandTTTarewithintheirlimitsprovideassurance thattheactualvaluesofF,Fxy'.randTdonotexceedtheassumedvalues.YerifyingFandFafterqxyreachfuelloadingpriortoexceeding 75$ofRATEDTHERMALPOWERprovidesadditional assurance thatthecorewasproperlyloaded.3/4.2.5DNBPARAMETERS ThelimitsontheDNBrelatedparameters assurethateachoftheparameters aremaintained withinthenormalsteadystateenvelopeofoperation assumedinthetransient andaccidentanalyses.

Thelimitsareconsistent withthesafetyanalysesassumptions andhavebeenanalytically demonstrated adequatetomaintainaminimunDNBRof>1.22throughout eachanalyzedtransient.

The12hourperiodicsurveillance oftheseparameters throughinstrument readoutissufficient toensurethattheparameters arerestoredwithintheirlimitsfollowing loadchangesandotherexpectedtransient operation.

The18monthperiodicmeasurement oftheRCStotalflowrateisadequatetodetectflow'egradation andensurecorrelationoftheflowindicationchannelswithmeasuredflowsuchthattheindicated percentflowwillprovidesufficient verification offlowrateona12hourbasis.ST.LUCIE-UNIT1B3/4Z-ZAmendment No.

+~

~~3/4.4REACTORCOOLANTSYSTEMBASES3/4.4.1REACTORCOOLANTLOOPSANDCOOLANTCIRCULATION Theplantisdesignedtooperatewithbothreactorcoolantloopsandassociated reactorcoolantpumpsinoperation, andmaintainDNBRabovetheDNBRlimitduringallnormaloperations andanticipated transients.

InNODES1and2withonereactorcoolantloopnotinoperation, thisspecification requiresthattheplantbeinatleastHOTSTANDBYwithin1hour.InMODE3,asinglereactorcoolantloopprovidessufficient heatremovalcapability forremovingdecayheat;however,singlefailureconsiderations requirethattwoloopsbeOPERABLE.

InNODE4,andinMODE5withreactorcoolantloopsfilled,asinglereactorcoolantlooporshutdowncoolingloopprovidessufficient heatremovalcapability forremovingdecayheat;butsinglefailureconsiderations requirethatatleasttwoloops(eithershutdowncoolingorRCS)beOPERABLE.

InNODE5withreactorcoolantloopsnotfilled,asingleshutdowncoolingloopprovidessufficient heatremovalcapability forremovingdecayheat;butsinglefailureconsiderations andtheunavailability ofthesteamgenerators asaneatremovingcomponent, requirethatatleasttwoshutdowncoolingloopsbeOPERABLE.

rTheoperation ofoneReactorCoolantPumporoneshutdowncoolingpumpprovidesadequateflowtoensuremixing,preventstratification andproducegradualreactivity changesduringboronconcentration reductions 1ntheReactorCoolantSystem.Thereactivity changerateassociated withboronreductions will,,therefore, bewithinthecapability ofoperatorrecognition andcontrol.Therestrictions onstartingaReactorCoolantPumpinMODE5withoneormoreRCScoldlegslessthanorequalto165'FareprovidedtopreventRCSpressuretransients, causedbyenergyadditions fromthesecondary system,whichcouldexceedthelimitsofAppendixGto10CFR50.TheRCSwillbeprotected againstoverpressure transients andwillnotexceedthelimitsofAppendixGbyeither1)restricting thewatervolumeinthepressurizer andtherebyproviding avolumefortheprimarycoolanttoexpandinto,or2)byrestricting startingoftheReactorCoolantPumpstowhenthe-secondary watertemperature ofeachsteamgenerator islessthan45'FaboveeachoftheReactorCoolantSystemcoldlegtemperatures.

3/4.4.2and3/4.4.3SAFETYVALVESThepressurizer codesafetyvalvesoperatetopreventtheRCSfrcmbeingpressurized abgveitsSafetyLimitof2750psia.Eachsafetyvalveisdesignedtorelieve2x10~lbs.perhourofsaturated steamatthevalvesetpoint.

Thereliefcapacityofasinglesafetyvalveisadequatetorelieveanyoverpressure condition'which couldoccurduringshutdown.

IntheeventthatnosafetyvalvesareOPERABLE, anoperating shutdowncoolingloop,connected totheRCS,providesoverpressure reliefcapability andwillpreventRCSoverpressurization.

ST.LUCIE-UNIT1B3/44-1Amendment No.

SAFETYEVALUATION RE:St.LucieUnit1DocketNo.50-335ProposedLicenseAmendment LinearHeatRateTechnical Secification

-FluxPeakinAumentation FactorsI.Introduction PastpracticeforECCSanalysishasbeentopostulate thataxialgapscanoccurinthefuelrodpellet.stack.Such.gapscouldtheoretically occurbecauseoffuelcolumndensification incombination withanincreaseinthecladdingovality.Withseverecreepovality,thepelletstackcouldbegrippedbythecladdingbeforedensification is'omplete suchthatagapwouldformbetweenpelletsasfurtherdensification occurs.Thisgapwouldlowerthefueldensityinahorizontal plane,resulting inanincreaseinthermalneutronfluxandhigherlocalrodpowers.Thispossiblepowerincreaseisusedinestablishing peakingfactorlimits.II.Evaluation ExxonNuclear(ENC)andFloridaPower6Light(FPL)havemadeacarefulevaluation oftheconditions thatarenecessary toformsuchgapsandhaveconcluded thatforENC-designed fuel,suchgapswillnotoccur.Thejustifi-cationforthispositionhasbeensubmitted totheUSNRCinsupportofarevisedcladcollapseprocedure inReference l.Thereasonsare:1.Densification iscompleteafterafewthousandMWD/MTexposure.

2.Ovalitydoesnotproceedtothepointthatpelletsaregrippedbythecladdinguntilafterfueldensifi-cationiscomplete.

Thisconclusion isverifiedbythecalculation ofovalityandcreepdown withtheCOLAPXandRODEX2fuelperformance codes.3.Theupperplenumspringactstokeepapositivepressureonthepelletstoovercomeresistance ofthepelletstacktodownwardmotion.Thespringisfabricated ofcreepresistant InconelX-750toavoidearlyloadrelaxation andisdesignedtoprovidepositivedownwardpressureovertherangeofpotential densification.

Toverifytheconclusion thatsignificant gapsarenot,formed,ENChasmadeanumberofscansofirradiated rodsandconfirmed thataxialgapsdonotexistedBecauseoftheseresultsnofluxpeakingaugmentation factorsarerequiredforENCdesignedfuel.ENChasperformed neutronics calculations forCombustion Engineering designedfuelwhichshowthat,thepeakrodpowerforCEfuelisatleast10%lessthanthepeakpowerforENCfuelduringCycle6.Becausethemaximumvalueofflux.peakingaugmentation factorsissignifi-cantlylessthan10%,noaugmentation factorneedbeappliedtoCEfuel.Therefore, FloridaPower8LightCompanyhasconcluded thatafluxpeakingaugmentation factorcurveneednotbecontained j.nSt.LucieUnit1Technical Specificat.ions.

III.Conclusion Basedontheconsiderations described above,(1)theproposedchangedoesnotincreasetheprobability orconsequences qfaccidents ormalfunctions ofequipment, important tosafetyanddoesnotreducethemarginofsafetyasdefinedinthebasisforanytechnical specification, therefore, thechangedoesnotinvolveasignificant hazardsconsideration, (2)thereisreason-ableassurance thatthehealthandsafetyofthepublicwillnotbeendangered byoperation intheproposedmanner,and(3)suchactivities wil'1beconducted incompliance withtheCommission's regulations andtheissuanceofthisamendment willnotbeinimicaltothecommondefenseandsecurityortothehealthandsafetyof'hepublic.

Reference:

(1)XN-NF-82-06,

'"Qualification of'ExxonNuclearFuelforExtendedBurnup",June1982.

STATEOFFLORiDA)))stRobertE.Uhribeingfirst.dulysworn,deposesandsays:ThatheisYicePresident ofFloridaPoweraLight,Company,theL>censeeherein;Thathehasexecutedtheforegoing document,;

that,thestate-mentsmadeinthissaid.documentaretrueandcorrecttothebestofhisknowledge, information, andbelief,andthatheisauthorized toexecutethedocumentonbehalfofsaidRobertE.UhrigSubscribed andsworntobeforemethisdayof19>10TARYPUBLiC,inandfortheCountyofDade,StateofFloridaNycommission expires: