ML17213B033
| ML17213B033 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 02/08/1983 |
| From: | FLORIDA POWER & LIGHT CO. |
| To: | |
| Shared Package | |
| ML17213B032 | List: |
| References | |
| NUDOCS 8302150008 | |
| Download: ML17213B033 (17) | |
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POWERDISTRIBUTIONLIMITSSURVEILLANCEREQUIREMENTScontinuedc.VerifyingthattheAXIALSHAPEINDEXismaintainedwithintheallowablelimitsofFigure3.2-2,where100percentofmaximumallowablepowerrepresentsthemaximumTHERMALPOWERallowedbythefollowingexpression:MxNwhere:1.MisthemaximumallowableTHERMALPOWERlevelfortheexistingReactorCoolantPumpcombination.2.NisthemaximumallowablefractionofRATEDTHERMALPOWERasdeterminedbytheFxcurveofFigure3.2-3..4.2.1.4IncoreDetectorMonitoringSystems-TheincoredetectormonitorsystemmaybeusedformonitoringthecorepowerdistributionbyverifyingthattheincoredetectorLocalPowerDensityalarms:a.Areadjustedtosatisfytherequirementsofthecorepowerdistributionmapwhichshallbeupdatedatleastonceper31daysofaccumulatedoperationinMODE1.b.HavetheiralarmsetpointadjustedtolessthanorequaltothelimitsshownonFigure3.2-1whenthefollowingfactorsareappropriatelyincludedinthesettingofthesealarms:.1.Ameasurementcalculationaluncertaintyfactorof1.07*,2.Anengineeringuncertaintyfactorof1.03,3.Alinearheatrateuncertaintyfactorof1.01duetoaxialfueldensificationandthermalexpansion,and4.ATHERMALPOWERmeasurementuncertaintyfactorof1.02.*Anuncertaintyfactorof1.10applieswheninLOADFOLLOWOPERATION.gIfthecoresystembecomesinoperable,reducepowertoMxNwithin4hoursandmonitorlinearheatrateinaccordancewithSpecification4.2.1.ST.LUCIE-UNIT13/42-2AmendmentNo.
/~~~'3/4.2:~PONER0ISTRIBUTIONLINITSBASES3/4.2.1LINEARHEATRATEThelimitationoflinearheatrateensuresthatintheeventofaLOCA,thepeaktemperatureofthefuelcladdingwillnotexceed2200'F.Eitherofthetwocorepowerdistributionmonitoringsystems,theExcoreDetectorMonitoringSystemandtheIncoreDetectorthonitoringSystem,provideadequatemonitoringofthecorepowerdistributionandarecapableofverifyingthatthelinearheatratedoesnotexceeditslimits.TheExcoreDetectorMonitoringSystemperformsthisfunctionbycontinuouslymonitoringtheAXIALSHAPEINDEXwiththeOPERABLEquadrantsymmetricexcoreneutron.fluxdetectorsandverifyingthattheAXIALSHAPEINDEXismaintainedwithintheallowablelimitsofFigure3.2-2.InconjuctionwiththeuseoftheexcoremonitoringsystemandinestablishingtheAXIALSHAPEINDEXlimits,thefollowingassumptionsaremade:1)theCEAinsertionlimitsofSpecifications3.1.3.5and3.1.3.6aresatisfied,2)theAZIMUTHALPOllERTILTrestrictionsofSpecification3.2.4aresatisfied,and3)theTOTALPLANARRADIALPEAKINGFACTORdoesnotexceedthelimitsofSpecification3.2.2.TheIncoreDetectortlonitoringSystemcontinuouslyprovidesadirectmeasureofthepeakingfactorsandthealarmswhichnavebeenestablishedfortheindividualincoredetectorsegmentsensurethatthepeaklinearheatrateswillb.maintainedwithintheallowablelimitsofFigure3.2-1.Thesetpointsforthesea'farmsincludeallowances,setintheconservativedirections,for1)ameasurement-calculationaluncertaintyfactorof1.07*,2)anengineeringunceit.aintyfactorof1.03,3)anallowanceof1.01foraxialfueldensificationandthermalexpansion,and4)aTHERMALPOWERmeasurementuncertaintyfactorof1.02.3/4.2.2,3/4.2.3and3/4.2.4TOTALPLANARANDINTEGRATEDRADIALPEAKINGFACTORSFyANDFrANDAZIMUTHALPOWERTILTTqThelimitationonFTandTareprovidedtoensurethattneassumptionsusedintheanalysisforBtablisflingtheLinearHeatRateandLocalPowerDensity-HighLCOsandLSSSsetpointsremainvalidduringoperationatthevariousallowableCEAgroupinsertionlimits.ThelimitationsonFTrandTqareprovidedtoensurethattheassumptions~Anuncertaintyfactorof1.10applieswheninLOADFOLLOWOPERATION.ST.LUCIE-UNIT183/42-1 O.
2.1SAFETYLIMITSBASES2.1.1REACTORCORETherestrictionsofthissafetylimitpreventoverheatingofthefuelcladdingandpossiblecladdingperforationwhichwouldresultinthereleaseoffissionproductstothereactorcoolant.Overheatingofthefuelispreventedbymaintainingthesteadystatepeaklinearheatratebelowthelevelatwhichcenterlinefuelmeltingwilloccur.Overheatingofthefuelcladdingispreventedbyrestrictingfueloperationtowithi'nthenucleateboilingregimewheretheheattransfercoefficientislargeandthecladdingsurfacetemperatureisslightlyabovethecoolantsaturationtemperature.Operationabovetheupperboundaryofthenucleateboilingregimecouldresultinexcessivecladdingtemperaturesbecauseoftheonsetofdeparturefrcmnucleateboiling(DNB)andtheresultantsharpreductioninheattransfercoefficient.DNBisnotadirectlymeasurableparameterduringoperationandthereforeTHERMALPOWERandReactorCoolantTemperatureandPressurehavebeenrelatedtoDNBthroughtheExxonXNBcorrelation.TheXNBDNBcorrelationhasbeendevelopedtopredicttheDNBfluxandthelocationofDNBforaxiallyuniformandnon-uniformheatfluxdistributions.ThelocalDNBheatfluxration,DNBR,definedastheratiooftheheatfluxthatwouldcauseDNBataparticularcorelocationtothelocalheatflux,isindicativeofthemargintoDNB.TheminimumvalueoftheDNBRduringsteadystateoperation,normaloperationaltransients,andanticipatedtransientsislimitedto1.22usingtheXNBDNBRcorrelation.Thisvaluecorrespondstoa95percentprobabilityata95percentconfidencelevelthatDNBwillnotoccurandischosenasanappropriatemargintoDNBforalloperatingconditions.ThecurvesofFigure2.1-1showthelociofpointsofTHERMALPOWER,ReactorCoolantSystempressureandmaximumcoldlegtemperature'ithfourReactorCoolantPumpsoperatingforwhichtheminimumDNBRisnolessthantheDNBRlimitforthefamilyofaxialshapesandcorrespondingradialpeaksshowninFigureB2.1-1.ThelimitsinFigure2.1-1werecalculatedforreactorcoolantinlettemperatureslessthanorequalto580'F.Thedashedlineof580'Fcoolantinlettemperatureisnotasafetylimit;however,operationabove580'Fisnotpossiblebecauseoftheactuationofthemainsteamlinesafetyvalveswhichlimitthemaximumvalueofreactorinlettemprature.ReactoroperationatTHERMALPOWERlevelshigherthan112$ofRATEDTHERMALPOWERisprohibitedbythehighpowerleveltripsetpointspecifiedinTable2.1-1.Theareaofsafeoperationisbelowandtotheleftoftheselines.ST.LUCIEUNIT1B2-1 SAFETYLIMITSBASESTheconditionsfortheThermalMargi'nSafetyLimitcurvesinFigure2.1-1tobevalidareshownonthefigure.ThereactorprotectivesysteminccmbinationwiththeLimitingConditionsforOperation,isdesignedtopreventanyanticipatedcombinationoftransientconditionsforreactorcoolantsystemtemperature,pressure,andthermalpowerlevelthatwouldresultinaDNBRoflessthantheDNBRlimitandprecludethe)existenceofflowinstabilities.2.1.2REACTORCOOLANTSYSTEMPRESSURETherestrictionofthisSafetyLimitprotectstheintegrityoftheReactorCoolantSystemforoverpressurizationandtherebypreventsthereleaseofradionuclidescontainedinthereactorcoolantfromreachingthecontainmentatmosphere.ThereactorpressurevesselandpressurizeraredesignedtoSectionIIIoftheASMECodeforNuclearPowerPlantcomponentswhichpermitsamaximumtransientpressureof11(g(2750psia)ofdesignpressure.TheReactorCoolantSystempiping,valvesandfittings,aredesignedtoANSIB31.7,ClassIwhichpermitsamaximumtransientpressureoflit@(2750psia)ofccmponentdesignpressure.TheSafetyLimitof2750psiaisthereforeconsistentwiththedesigncriteriaandassociatedcoderequiranents.TheentireReactorCool.antSystemishydrotestedat3125psiatodemonstrateintegritypriortoinitialoperation.ST.LUCIE-UNIT1B2-3AmendmentNo.
2.2LIMITINGSAFETYSYSTEMSETTINGSBASESReactorCoolantFlow-Low(Continued)reactorcoolantpumpsaretakenoutofservice.Thelow-flowtripsetpointsandAllowableValuesforthevariousreactorcoolantpumpcombinationshavebeenderivedinconsiderationofinstrumenterrorsandresponsetimesofequipmentinvolvedtomaintaintheDNBRabovetheDNBRlimitundernormaloperationandexpectedtransients.Forreactoroperationwithonlytwoorthreereactorcoolantpumpsoperating,theReactorCoolantFlow-Lowtripsetpoints,thePowerLevel-Hightripsetpoints,andtheThermalMargin/LowPressuretripsetpointsareautomaticallychangedwhenthepumpconditionselectorswitchismanuallysettothedesiredtwo-orthree-pumpposition.Changingthesetripsetpointsduringtwoandthreepumpoperationpreventstheminimum.valueofDNBRfrcmgoingbelowtheDNBRlimitduringnormaloperationaltransientsandanticipatedtransientswhenonlytwoorthreereactorcoolantpumpsareoperating.PressurizerPressure-HighThePressurizerPressure-Hightrip,backedupbythepressurizercodesafetyvalvesandmainsteamlinesafetyvalves,providesreactorcoolantsystemprotectionagainstoverpressurizationintheeventoflossofloadwithoutreactortrip.Thistrip~'ssetpointis100psibelowthenaninalliftsetting(2500psia)ofthepressurizercodesafetyvalvesanditsconcurrentoperationwiththepower-operatedreliefvalvesavoidstheundesirableoperationofthepressurizercodesafetyvalves.ContairmentPressure-HighTheContairmentPressure-Hightripprovidesassurancethatareactortripisinitiatedconcurrentlywithasafetyinjection.SteamGeneratorPressure-LowTheSteamGeneratorPressure-Lowtripprovidesprotectionagainstanexcessiverateofheatextractionfromthesteamgeneratorsandsubsequentcooldownofthereactorcoolant.Thesettingof600psiaissufficientlybelowthefull-loadoperatingpointof800psigsoasnotST.LUCIE-,UNIT1B2-.5AnendmentNo.
LIMITINGSAFETYSYSTEMSETTINGSBASESThermalMarin/LowPressureTheThermalMargin/LowPressuretripisprovidedtopreventoperationwhentheDNBRislessthantheDNBRlimit.Thetripisinitiatedwheneverthereactorcoolantsystempressuresignaldropsbeloweither1887psiaoraccmputedvalueasdescribedbelow,whicheveris'igher.TheccmputedvalueisafunctionofthehigherofhTpowerorneutronpower,reactorinlettemperature,thenumberofreactorcoolantpumpsoperatingandtheAXIALSHAPEINDEX.Theminimumvalueofreactorcoolantflowrate,themaximumAXIMUTHALPOWERTILTandthemaximumCEAdeviationpermittedforcontinuousoperationareassumedinthegenerationofthistripfunction.'naddition,CEAgroupsequencinginaccordancewithSpecifications3.1.3.5and3.1.3.6isassumed.Finally,themaximuminsertionofCEAbankswhichcanoccurduringanyanticipatedoperationaloccurrencepriortoaPowerLevel-Hightripisassumed.TheThermalMargin/LowPressuretripsetpointsincludeappropriateallowancesforequipmentresponsetime,calculationalandmeasurementuncertainties,andprocessingerror.Afurtherallowanceof30psiaisincludedtocompensateforthetimedelayassociatedwithprovidingeffectiveterminationoftheoccurrencethatexhib1tsthemostrapiddecreaseinmargintotheDNBRlimit.AsymmetricSteamGeneratorTransientProtectiveTripFunctionASGTPTFTheASGTPTFconsistsofSteamGeneratorpressureinputstotheTM/LPcalculator,whichcausesareactortripwhenthedifferenceinpressurebetweenthetwosteamgeneratorsexceedsthetripsetpoint.TheASGTPTFisdesignedtoprovideareactortripforthoseeventsassociatedwithsecondarysystanmalfunctionswhichresultinasymmetricprimaryloopcoolanttemperatures.Themostlimitingeventisthelossofloadtoonesteamgeneratorcausedbyasinglemainsteamisolationvalveclosure.Theequipmenttripsetpointandallowablevaluesarecalculatedtoaccountforinstrumentuncertainties,andwillensureatripatorbeforereachingtheanalysissetpoint.ST.LUCIE-UNIT1B2-7
POWERDISTRIBUTIONLIMITSBASESusedintheanalysisestablishingtheDNBMarginLCO,andThermalMargin/LowPressureLSSSsetpointsremainvalidduringoperationatthevariousal1owableCEAgroupinsertionLimits.IfF,ForTexceedxy'theirbasiclimitations,operationmaycontinueundertheadditionalrestrictionsimposedbytheACTIONstatementssincetheseadditionalrestrictionsprovideadequateprovisionstoassurethattheassumptionsusedinestablishingtheLinearHeatRate,ThermalMargin/LowPressureandLocalPowerDensity-HighLCOsandLSSSsetpointsremainvalid.AnAZIMUTHALPO'WERTILT)0.10isnotexpectedandifitshouldoccur,subsequentoperationwouldberestrictedtoonlythoseoperationsrequiredtoidentifythecauseofthisunexpectedtilt.ThevalueofTthatmustbeusedintheequationF=F(1+T)qandF=F(1,+T)isthemeasuredtilt.rr'ThesurveillancerequirementsforverifyingthatF,FandTTTarewithintheirlimitsprovideassurancethattheactualvaluesofF,Fxy'.randTdonotexceedtheassumedvalues.YerifyingFandFafterqxyreachfuelloadingpriortoexceeding75$ofRATEDTHERMALPOWERprovidesadditionalassurancethatthecorewasproperlyloaded.3/4.2.5DNBPARAMETERSThelimitsontheDNBrelatedparametersassurethateachoftheparametersaremaintainedwithinthenormalsteadystateenvelopeofoperationassumedinthetransientandaccidentanalyses.ThelimitsareconsistentwiththesafetyanalysesassumptionsandhavebeenanalyticallydemonstratedadequatetomaintainaminimunDNBRof>1.22throughouteachanalyzedtransient.The12hourperiodicsurveillanceoftheseparametersthroughinstrumentreadoutissufficienttoensurethattheparametersarerestoredwithintheirlimitsfollowingloadchangesandotherexpectedtransientoperation.The18monthperiodicmeasurementoftheRCStotalflowrateisadequatetodetectflow'egradationandensurecorrelationoftheflowindicationchannelswithmeasuredflowsuchthattheindicatedpercentflowwillprovidesufficientverificationofflowrateona12hourbasis.ST.LUCIE-UNIT1B3/4Z-ZAmendmentNo.
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~~3/4.4REACTORCOOLANTSYSTEMBASES3/4.4.1REACTORCOOLANTLOOPSANDCOOLANTCIRCULATIONTheplantisdesignedtooperatewithbothreactorcoolantloopsandassociatedreactorcoolantpumpsinoperation,andmaintainDNBRabovetheDNBRlimitduringallnormaloperationsandanticipatedtransients.InNODES1and2withonereactorcoolantloopnotinoperation,thisspecificationrequiresthattheplantbeinatleastHOTSTANDBYwithin1hour.InMODE3,asinglereactorcoolantloopprovidessufficientheatremovalcapabilityforremovingdecayheat;however,singlefailureconsiderationsrequirethattwoloopsbeOPERABLE.InNODE4,andinMODE5withreactorcoolantloopsfilled,asinglereactorcoolantlooporshutdowncoolingloopprovidessufficientheatremovalcapabilityforremovingdecayheat;butsinglefailureconsiderationsrequirethatatleasttwoloops(eithershutdowncoolingorRCS)beOPERABLE.InNODE5withreactorcoolantloopsnotfilled,asingleshutdowncoolingloopprovidessufficientheatremovalcapabilityforremovingdecayheat;butsinglefailureconsiderationsandtheunavailabilityofthesteamgeneratorsasaneatremovingcomponent,requirethatatleasttwoshutdowncoolingloopsbeOPERABLE.rTheoperationofoneReactorCoolantPumporoneshutdowncoolingpumpprovidesadequateflowtoensuremixing,preventstratificationandproducegradualreactivitychangesduringboronconcentrationreductions1ntheReactorCoolantSystem.Thereactivitychangerateassociatedwithboronreductionswill,,therefore,bewithinthecapabilityofoperatorrecognitionandcontrol.TherestrictionsonstartingaReactorCoolantPumpinMODE5withoneormoreRCScoldlegslessthanorequalto165'FareprovidedtopreventRCSpressuretransients,causedbyenergyadditionsfromthesecondarysystem,whichcouldexceedthelimitsofAppendixGto10CFR50.TheRCSwillbeprotectedagainstoverpressuretransientsandwillnotexceedthelimitsofAppendixGbyeither1)restrictingthewatervolumeinthepressurizerandtherebyprovidingavolumefortheprimarycoolanttoexpandinto,or2)byrestrictingstartingoftheReactorCoolantPumpstowhenthe-secondarywatertemperatureofeachsteamgeneratorislessthan45'FaboveeachoftheReactorCoolantSystemcoldlegtemperatures.3/4.4.2and3/4.4.3SAFETYVALVESThepressurizercodesafetyvalvesoperatetopreventtheRCSfrcmbeingpressurizedabgveitsSafetyLimitof2750psia.Eachsafetyvalveisdesignedtorelieve2x10~lbs.perhourofsaturatedsteamatthevalvesetpoint.Thereliefcapacityofasinglesafetyvalveisadequatetorelieveanyoverpressurecondition'whichcouldoccurduringshutdown.IntheeventthatnosafetyvalvesareOPERABLE,anoperatingshutdowncoolingloop,connectedtotheRCS,providesoverpressurereliefcapabilityandwillpreventRCSoverpressurization.ST.LUCIE-UNIT1B3/44-1AmendmentNo.
SAFETYEVALUATIONRE:St.LucieUnit1DocketNo.50-335ProposedLicenseAmendmentLinearHeatRateTechnicalSecification-FluxPeakinAumentationFactorsI.IntroductionPastpracticeforECCSanalysishasbeentopostulatethataxialgapscanoccurinthefuelrodpellet.stack.Such.gapscouldtheoreticallyoccurbecauseoffuelcolumndensificationincombinationwithanincreaseinthecladdingovality.Withseverecreepovality,thepelletstackcouldbegrippedbythecladdingbeforedensificationis'ompletesuchthatagapwouldformbetweenpelletsasfurtherdensificationoccurs.Thisgapwouldlowerthefueldensityinahorizontalplane,resultinginanincreaseinthermalneutronfluxandhigherlocalrodpowers.Thispossiblepowerincreaseisusedinestablishingpeakingfactorlimits.II.EvaluationExxonNuclear(ENC)andFloridaPower6Light(FPL)havemadeacarefulevaluationoftheconditionsthatarenecessarytoformsuchgapsandhaveconcludedthatforENC-designedfuel,suchgapswillnotoccur.Thejustifi-cationforthispositionhasbeensubmittedtotheUSNRCinsupportofarevisedcladcollapseprocedureinReferencel.Thereasonsare:1.DensificationiscompleteafterafewthousandMWD/MTexposure.2.Ovalitydoesnotproceedtothepointthatpelletsaregrippedbythecladdinguntilafterfueldensifi-cationiscomplete.ThisconclusionisverifiedbythecalculationofovalityandcreepdownwiththeCOLAPXandRODEX2fuelperformancecodes.3.Theupperplenumspringactstokeepapositivepressureonthepelletstoovercomeresistanceofthepelletstacktodownwardmotion.ThespringisfabricatedofcreepresistantInconelX-750toavoidearlyloadrelaxationandisdesignedtoprovidepositivedownwardpressureovertherangeofpotentialdensification.
Toverifytheconclusionthatsignificantgapsarenot,formed,ENChasmadeanumberofscansofirradiatedrodsandconfirmedthataxialgapsdonotexistedBecauseoftheseresultsnofluxpeakingaugmentationfactorsarerequiredforENCdesignedfuel.ENChasperformedneutronicscalculationsforCombustionEngineeringdesignedfuelwhichshowthat,thepeakrodpowerforCEfuelisatleast10%lessthanthepeakpowerforENCfuelduringCycle6.Becausethemaximumvalueofflux.peakingaugmentationfactorsissignifi-cantlylessthan10%,noaugmentationfactorneedbeappliedtoCEfuel.Therefore,FloridaPower8LightCompanyhasconcludedthatafluxpeakingaugmentationfactorcurveneednotbecontainedj.nSt.LucieUnit1TechnicalSpecificat.ions.III.ConclusionBasedontheconsiderationsdescribedabove,(1)theproposedchangedoesnotincreasetheprobabilityorconsequencesqfaccidentsormalfunctionsofequipment,importanttosafetyanddoesnotreducethemarginofsafetyasdefinedinthebasisforanytechnicalspecification,therefore,thechangedoesnotinvolveasignificanthazardsconsideration,(2)thereisreason-ableassurancethatthehealthandsafetyofthepublicwillnotbeendangeredbyoperationintheproposedmanner,and(3)suchactivitieswil'1beconductedincompliancewiththeCommission'sregulationsandtheissuanceofthisamendmentwillnotbeinimicaltothecommondefenseandsecurityortothehealthandsafetyof'hepublic.
Reference:
(1)XN-NF-82-06,'"Qualificationof'ExxonNuclearFuelforExtendedBurnup",June1982.
STATEOFFLORiDA)))stRobertE.Uhribeingfirst.dulysworn,deposesandsays:ThatheisYicePresidentofFloridaPoweraLight,Company,theL>censeeherein;Thathehasexecutedtheforegoingdocument,;that,thestate-mentsmadeinthissaid.documentaretrueandcorrecttothebestofhisknowledge,information,andbelief,andthatheisauthorizedtoexecutethedocumentonbehalfofsaidRobertE.UhrigSubscribedandsworntobeforemethisdayof19>10TARYPUBLiC,inandfortheCountyofDade,StateofFloridaNycommissionexpires: