ML17255A590

Proposed Tech Spec Allowing Insertion of 14x14 Optimized Fuel Assembly Design for Cycle 14 Reload

ML17255A590
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Site:	Ginna
Issue date:	12/20/1983
From:	ROCHESTER GAS & ELECTRIC CORP.
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TECHNICALSPECIFICATIONS1.0DEFINITIONS1.2Thefollowingtermsaredefinedforuniforminterpretationofthespecifications.ThermalPowerTheratethatthethermalenergygeneratedbythefuelisaccumulatedbythecoolantasitpassesthroughthereactorvessel.Reactor0eratinModesModeReactivityakk'oolantTemperature1.3RefuelingColdShutdownHotShutdownOperatingWQ5avg.avgavgavg140200540580Anyoperationwithinthecontainmentinvolvingmovementoffueland/orcontrolrodswhenthevesselheadisunbolted.1.4~OerableCapableofperformingallintendedfunctionsintheintendedmanner.S4OiOaO35OGOOOa4+-----pBS<mo,'POPAQQCpDRPAmendmentNo.Proposed i'

regimeistermeddeparturefromnucleateboiling(DNB)andatthispointthereisasharpreductionoftheheattransfercoefficientwhichwouldresultinhighcladtemperaturesandthepossibilityofcladfailure.DNBisnot,however,anobservableparameterduringreactoroperation.Therefore,theobservableparameters,thermalpower,reactorcoolanttemperatureandpressurehavebeenrelatedtoDNBthroughtheW-3and/orWRB-1,DNBcorrelation.TheseDNBcorrelationshavebeendevelopedtopredicttheDNBfluxandthelocationofDNBforaxiallyuniformandnon-uniformheatfluxdistributions.ThelocalDNBheatfluxratio,definedastheratiooftheheatfluxthatwouldcauseDNBataparticularcorelocationtothelocalheatflux,isindi-cativeofthemargintoDNB.AminimumvalueoftheDNBratio,MDNBR,isspecifiedsothatduringsteadystateoperation,normaloperationaltransientsandanticipatedtransients,thereisa95%probabilityata95%confidencelevelthatDNBwillnotoccur.(1)ThecurvesofFigure2.1-1representthelociofpointsofthermalpower,coolantsystempressureandaveragetemperatureforwhichthisminimumDNBvalueissatisfied.Theareaofsafeoperationisbelowtheselines.Proposed Sinceitispossibletohavesomewhatgreaterenthalpyrisehotchannelfactorsatpartpowerthanatfullpowerduetothedeepercontrolbankinsertionwhichispermittedatpartpower,aconservativeallowancehasbeenmadeinobtainingthecurvesinFigure2.1-1foranincreaseinFHwithdecreasingpowerlevels.Rodwithdrawalblockandloadrunbackoccursbeforereactortripsetpointsarereached.TheReactorControlandProtectiveSystemisdesignedtopreventanyanticipatedcombinationoftransientconditionsforreactorcoolantsystemtemperature,pressureandthermalpowerlevelthatwouldresultintherebeinglessthana95%probabilityata95%confidencelevelthatDNBwouldnotoccur.(3)AmendmentNo.March30,1976Proposed

(1)FSAR,Section3.2.2(2)FSAR,Section3.2.1(3)FSAR,Section14.1.1Proposed

FIGURE2.1-1COREDNBSAFETYLIMITS2LOOPOPERATION668'658645-635:638625628o6l56l86852400PSIA~00gPgg~l))~Sp~UNACCEPTABLEOPERATION595598585588575578ACCEPTABLEOPERATION8..l.2~3~45.6.7.8.91.l.llPOVER(tractionof'ominal)AmendmentNo.Proposed d.OvertemperaturehT-DT[Kl+K2(PP)-K3(TT)1+x2SwherehT=indicatedhTatratedpower,'F0T=averagetemperature,'FT=5735FP=pressurizerpressure,psigP=2235psig1K=1.201K2=.000900K=.02093vl=25sect2=5secandf(DI)isafunctionoftheindicateddiffer-encebetweentopandbottomdetectorsofthepower-rangenuclearionchambers;withgainstobeselectedbasedonmeasuredinstrumentresponseduringplantstartuptestswhereqtandqbarethepercentpowerinthetopandbottomhalvesofthecorerespectively,andq+qbisthetotalcorepowerinpercentofratedpowersuchthat:(i)forqt-qblessthan+21percent,f(hI)=02~32AmendmentNo.March30,1976Proposed 0

(ii)foreachpercentthatthemagnitudeofqt-qbismorepositvethan+21percent,thebTtripsetpointshallbeautomaticallyreducedbyanequivalentof1.6percentofratedpower.OverpowerbTDT[K4Kg(TT)K63S+1]+f(6?)whereTTlK~K5K6T3f(zI)indicatedhTatratedpower,'Faveragetemperature,'FindicatedTavgatnominalconditionsatratedpower,'F1.077.0.0forT<T0.0011forT>T0.0262forincreasingT0.0fordecreasingT10secasdefinedin2.3.1.2.d.2~33Amendment.No.March30,1976proposed PressurizerWheneverthereactorisathotshutdownorcriticalthepressurizershallhaveatleast100kwofheatersoperableandawaterlevelmaintainedbetween12%and87%oflevelspan.Ifthepressurizerisinoperableduetoheatersorwaterlevel,restorethepressurizertooperablestatuswithin6hrs.orhavetheRHRsysteminoperationwithinanadditional6hrs.BasesTheplantisdesignedtooperatewithallreactorcoolantloopsinoperationandmaintaintheDNBRabovethelimitvalueduringallnormal3.1-4bChangeNo.AmendmentNo.Proposed

MinimumConditionsforCriticalitExceptduringlowpowerphysicstests,thereactorshallnotbemadecriticalatatemperaturebelow500'F,andifthemoderatetemperaturecoefficientismorepositivethana.5pcm/'F(below70percentofratedthermalpower)b.0pcm/'F(atorabove70percentofratedthermalpower)3.1.3.23.1.3.3BasisInnocaseshallthereactorbemadecriticalaboveandtotheleftofthecriticalitylimitlineshownonFigure3.1-1ofthesespecifications.Whenthereactorcoolanttemperatureisbelowtheminimumtemperaturespecifiedabove,thereactorshallbesubcriticalbyanamountequaltoorgreaterthanthepotentialreactivityinsertionduetodepressurization.PrevioussafetyanalyseshaveassumedthatforDesignBasisEvents(DBE)initiatedfromthehotzeropowerorhigherpowercondition,themoderatortemperaturecoefficient(MTC)was.eitherzeroornegative.BeginninginCycle14,thesafetyanalyseshaveassumedthatamaximumMTCof+5pcm/Fcanexistupto70%power.AnalyseshaveshownthatthedesigncriteriacanbesatisfiedfortheDBE'swiththisassumption.Atgreaterthan(3)70%powertheMTCmustbe'zeroornegative.Proposed ThelimitationsonMTCarewaivedforlowpowerphysicsteststopermitmeasurementoftheMTCandotherphysicsdesignparametersofinterest.Duringthesetestsspecialoperatingprecautionswillbetaken.3.1-19proposed Therequirementthatthereactorisnottobemadecriticalaboveandtotheleftofthecriticalitylimitprovidesincreasedassurancethattheproperrelationshipbetweenreactorcoolantpressureandtemperaturewillbemaintainedduringsystemheatupandpressurization.Heatuptothistemperaturewillbeaccom-plishedbyoperatingthereactorcoolantpumps.Ifthespecifiedshutdownmarginismaintained,thereisnopossibilityofanaccidentalcriticalityasaresultofanincreaseinmoderatortemperatureoradecreaseofcoolantpressure.Reference(1)FSARTable3.2.1-1(2)FSARFigure3.2.1-8(3)SafetyEvaluationforR.E.GinnaTransitionto14x14OptimizedFuelAssemblies,WestinghouseElectricCorporation,November1983.AmendmentNo.Proposed

topublichealthandsafety.Wheneverchangesarenotbeing(1)madeincoregeometryonefluxmonitorissufficient.Thispermitsmaintenanceoftheinstrumentation.Continuousmoni-toringofradiationlevelsandneutronfluxprovidesimmediateindicationofanunsafecondition.Theresidualheatpumpisusedtomaintainauniformboronconcentration.Theshutdownmarginasindicatedwillkeepthecoresubcritical,evenifallcontrolrodswerewithdrawnfromthecore.Duringrefueling,thereactorrefuelingcavityisfilledwithapproxi-'ately230,000gallonsofboratedwater.Theboronconcentrationofthiswaterat2000ppmboronissufficienttomaintainthereactorsubcriticalbyatleast5%Dk/kinthecoldconditionwithallrodsinserted(bestestimateof10%subcritical),andwillalsomaintainthecoresubcriticalevenifnocontrolrodswereinsertedintothereactor.Periodicchecksofrefueling(2)waterboronconcentrationinsurethepropershutdownmargin.Communicationrequirementsallowthecontrolroomoperatortoinformthemanipulatoroperatorofanyimpendingunsafeconditiondetectedfromthemaincontrolboardindicatorsduringfuelmovement.Inadditiontotheabovesafeguards,interlocksareutilizedduringrefuelingtoinsuresafehandling.Anexcessweightinterlockis3.8-3Proposed

providedontheliftinghoisttopreventmovementofmorethanonefuelassemblyatatime.Thespentfueltransfermechanismcanaccommodateonlyonefuelassemblyatatime.Inadditioninterlocksontheauxiliarybuildingcranewillpreventthetrolleyfrombeingmovedoverstoragerackscontainingspentfuel.Theoperabilityrequirementsforresidualheatremovalloopswillensureadequateheatremovalwhileintherefuelingmode.Therequirementfor23feetofwaterabovethereactorvesselflangewhilehandlingfuelandfuelcomponentsincontainmentiscon-sistentwiththeassumptionsofthefuelhandlingaccidentanalysis.

References:

(1)FSAR-Section9.5.2(2)ReloadTransitionSafetyReport,Cycle14(3)FSAR-Section9.3.13.8-4AmendmentNo.

IIaveragepowertiltratioshallbedeterminedonceadaybyatleastoneofthefollowingmeans:a.Movabledetectorsb.Core-exitthermocouples3.10.2.2Powerdistributionlimitsareexpressedashotchannelfactors.Atalltimes,exceptduringlowpowerphysicsteststhehotchannelfactorsmustmeetthefollowinglimits:F(Z)=(2.32/P)*K(Z)QF(Z)=4.64*K(Z)QFDH=1.66[1+.3(1-P)]forPR.5forP<~5for0<P<1.00wherePisthefractionofratedpoweratwhichthecoreisoperating,K(Z)isthefunctiongivenbyFigure3.10N3,andZistheheightinthecore.ThemeasuredFshallbeincreasedbygreepercenttoyieldF.IfthemeasuredForFhexceedsthelimitinsIvalue,withduea118wancePcrmeasurementerror,themaximumallowablereactorpowerlevelandtheNuclearOverpowerTripsetpointshallbereducedonpercentforeachpercentwhichFDorFexceedsthelimitingvalue,whicheverismor8restiRctive.Ifthehotchannelfactorscannotbereducedbelowthelimitingvalueswithinoneday,theOverpowerhTtripsetpointandtheOvertemperaturehTtripsetpointshallbesimilarlyreduced.3.10.2.3Exceptforphysicstests,ifthequadranttoaveragepowertiltratio,exceeds1.02butislessthan1.12,thenwithintwohours:a.Correctthesituation,orb.Determinebymeasurementthehotchannelfactors,andapplySpecification3.10.2.2,orC.Limitpowerto75%ofratedpower.3.10-3AmendmentNo.g,P4Proposed

Ifthequadranttoaveragepowertiltratioexceeds1.02butislessthan1.12forasustainedperiodofmorethan24hourswithoutknowncause,orifsuchatiltrecursintermittentlywithoutknowncause,thereactorpowerlevelshallberestrictedsoasnottoexceed50%ofratedpower.Ifthecauseofthetiltisdetermined,continuedoperationatapowerlevelconsistentwith3.10.2.2above,shallbepermitted.Exceptforphysicstest,ifthequadranttoaveragepowertiltratiois1.12orgreater,thereactorshallbeputinthehotshutdownconditionutilizingnormaloperatingprocedures.Subsequentoperationforthepurposeofmeasuringandcorrectingthetiltisper-mittedprovidedthepowerleveldoesnotexceed50%ofratedpowerandtheNuclearOverpowerTrip"setpointisreducedby50%".Followinganyrefuelingandatleasteveryeffectivefullpowermonththereafter,fluxmaps,usingthemovabledetectorsystem,shallbemadetoconfirmthatthehotchannelfactorlimitsofSpecification3.10.2.2aremet.Thereferenceequilibriumindicatedaxialfluxdifferenceasafunctionofpowerlevel(calledthetargetfluxdifference)shallbemeasuredatleastonceperequivalentfullpowerquarter.Thetargetfluxdifferencemustbeupdatedatleasteachequivalentfullpowermonthusingameasuredvalueorbylinearinterpolationusingthemostrecentmeasuredvalueandthepredictedvalueattheendofthecyclelife.Exceptduringphysicstests,controlrodexercises,excoredetectorcalibration,andexceptasmodifiedby3.10.2.9through3.10.2.12,theindicatedaxialfluxdifferenceshallbemaintainedwithini5%ofthetargetfluxdifference(definesthetargetbandonaxialfluxdifference).Axialfluxdifferenceforpowerdistributioncontrolisdefinedastheaveragevalueforthefourexcoredetectors.Ifoneexcoredetectorisoutofservice,theremainingthreeshallbeusedtoderivetheaverage.3.10-4AmendmentNo.+Proposed 3.00eI.jilI~I(I;<<Ie-'(illeIII~lI'~e~~~jII.~IIIe~:I'.!e~ee~~IgjI~.I.:)Ie<<e-ITee~II~~~IIe<<[~~~~~ONELOOPOPERATION2.00~eO'jOJOeIsrhJf-/-1.00OJOCC3ODIll0.0l~I:II~~~~I;Il00I~IIIl>eI;i<<~,"~IJIeli<iislIeLII'Is>i~~e~I-.l.erlibel1000ell:Iej;I<<:.I<<II;Jlje50!I.'I'I'.!jile~~.e.I)'Ij.ejj<<fTMOLOOPOPERATIONCOOLANTBORONCONCENTRATION(PPN)RE(VIREOSHUT00MNMARGINF'TrierStn-rPROPOSED 1.500uFIGURE3.10-31.2500NORMALIZEOAXIALOEPENOENCEFACTORFORFQVS.ELEVATION1.00000.7500Ihi00000.2500TOTAI.FO2'.320COREHEIGHT0.0006.00010.80012.000K{7)f.000f.0000.9400.6470.0CDCDCDEUCDCDCD~t'DEOCOREHEIGHT(FT)C)CDCDEX)CDamendmentt]o.gg,gpPROPOSEDCDAJ AppendixBBeginningwiththereloadforCycle14,scheduledforinsertioninthespringof1984,RochesterGas6ElectricwillusetheWestinghouseOptimizedFuelAssembly(OFA)14x14designwithnaturaluraniumaxialblankets.InordertostoreandusefuelassembliesofthisdesignseveralchangestoGinnaTechnicalSpecificationsarerequired.OnFebruary23,1982,RG&ErequestedachangetotheTechnicalSpecificationtopermitstorageofthehigherenrichmentOFAfuelinthespentfuelpool.InresponsetoquestionsfromtheNRCstaffconcerningthissubmittalRGSEprovidedacriticalityanalysisofthenewfuelstorageracksonSeptember12,1983.AttachedarethreereportscomprisingthesafetyanalysispreparedbyWestinghousecoveringthetransitionfromanallExxonfueledcoretoafullcoreoftheOFAdesign.Thissafetyanalysisisnotcyclespecific,butusesparameterswhichwillbound,thoseexperiencedduringthetransitionperiod.Thesafetyanalysisiscomposedofasummaryofthemechanical,thermal-hydraulicandaccidentanalysisanddetailedresultsofthenon-LOCAandLOCAanalysis.TheseanalysesincorporatetheproposedchangestotheTechnicalSpecificationsandshowthattheapplicabledesigncriteriafortheExxonandOFAaresatisfied..Inbrief,theproposedchangestotheTechnicalSpecificationsarethefollowing:1.AllowingapositiveMTC(+5pcm'F)upto70%power.2.AreductioninshutdownmarginatEOCfrom1900,pcmto1800pcm.N3.AchangeintheFhHlimitsat,lessthan100%power.4.Achangeinthecoreprotectionlimits(OTDTandOPDTsetpointequations).5.AdeletionofthelimitsonTargetAxialOffset.Thefirstfourchangesareincorporatedintotheaccidentanalyses.Thedeletionofthelimitontargetaxialoffset(TAO)isnottreatedexplicitlyintheWestinghousesafetyanalysis.Worstcasepowerdistributionsthatboundanythat,wouldoccurduringoperationareassumedbyWestinghouse.ForeveryreloadWestinghousemustassurethatthepotentialworstcasepowerdistributiondoesnotexceedthoseassumedinthesafetyanalysis.Therefore,thelimitationonTAOisunnecessary.ThedeletionofthelimitationsisconsistentwiththeprovisionsoftheStandardTechnicalSpecification.

0~y Fourmigsoxideassemblies(MOX)willremaininthecoreforCycle14..TheseassembliesaremechanicallyidenticaltothewestinghouseHIFARdesignusedasreloadfueltoGinnaprjy~toCycle8.Exxonpreviouslyhasperformedasafetyanalysisandconcludedonabestestimatebasisthatinamixedcoreconfigurationtheflowtoeachassemblywaswithinonepercentofthecoreaverage.ApplyingaDNBRpenaltyequivalenttoadecreaseinonepercentofflowtotheminimumDNBRforExxonfuelcalculatedbyWestinghouseindicatesthatsufficientmargintothedesignDNBRlimitexists.pferanalysesremainvalid,aspreviouslyapprovedbytheNRC.

Reference1.Letter,D.C.Ziemann,USNRCtoL.D.White,RG&EApril15,1980.2.R.E.GinnaNuclearPlantCycle8SafetyAnalysisReport,ExxonNuclearCompany,December,1977.

AttachmentCInaccordancewith10CFR50.91thesechangestotheTechnicalSpecificationshavebeenevaluatedagainstthreecriteriatodetermineiftheoperationofthefacilityinaccordancewiththeproposedamendmentwould:1.involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated;or2.createthepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated;or3.involveasignificantreductioninamarginofsafety.Asoutlinedbelow,RochesterGas6Electricsubmitsthat,theissuesassociatedwiththisamendmentrequestareoutsidethecriteriaof10CFR50.91,andtherefore,anosignificanthazardsfindingiswarranted.Theproposedchangesarerequiredtoallowtheinsertionof,andsubsequenttransitionto,afullcoreoffuelassembliesoftheWestinghouseOptimizedFuelAssemblyDesign(W-OFA).ThesechangeshavebeenincorporatedintotheassumptionsandmethodologyusedbyWestinghousetoverifythataDesignBasisEventdoesnotcausetheappropriateacceptancecriteriatobeviolated.Inallcasestheassumptions,methodsandresultsareconsistentwithWestinghousestandardreloadsafetyevaluationtechniquesandotherplantsubmittalstotheNRCforinsertionofW-OFA.Therefore,anosignificanthazardsfindingiswarrantedforthefollowingreasons:TheinsertionofW-OFAfuelassemblieswillnotcauseanincreaseintheprobabilityofanyaccident,andbecausetheacceptancecriteriaaresatisfied,theconsequencesofanaccidentarenotincreased.2.Thepossibilityofanewordifferentkindofaccidentisnotcreated.3.Whileitisnotpossibletosimplycomparetheresultstopreviousanalysesbecauseofthedifferentanalyticaltechniquesusedbyvendors,andtheconstantevolutionoftheirmethods,theWestinghouseanalysishasdemon-stratedthatappropriatemarginexistsbetweenresultsandtheacceptancecriteria.

SafetyEvaluationforR.E.GinnaTransitiontoWestinghouse14xl4OptimizedFuelAssembliesEditedbyJ.C.MillerRochesterGasandElec:ricCorporationOocketNo.50-244Approved:M.G.Arlotti,ManagerFuelLicensngandProoramSuppor.WestinghouseElec=ricCorporationNuclearEnergySys.emsNuclearFuelDivis'.onP.0.Box39'.2Pittsburgh,PA152300710L:6

TABLEOFCONTENTSSectionPage

1.0INTRODUCTION

2.0SUMMARYANDCONCLUSIONS2"13.0MECHANICALEVALUATION3-14.0NUCLEAREVALUATION4-15.0THERMALANDHYDRAULICEVALUATION6.0ACCIDENTEVALUATION6-

17.0REFERENCES

ATTACHMENTATECHNICALSPECIFICATIONS7-1ATTACHMENTBNON-LOCAACCIDENTANALYSISFSARCHAPTER14ATTACHMENTCLOCAACCIDENTANALYSISFSARSECTIONS14.3.1/14.3.20710L:6 LISTOFTABLESTableNo.~Pae1FSARChapter14AccidentAnalysisSensitivitytoProposedChanges6-6LISTOFFIGURES~FiureNu.~Pae1R.E.Ginna14x14OFA3-50710L:61-2

1.0INTRODUCTION

R.E.GinnaisaWestinghousedesignedPWRandiscurrentlyoperatingwithanallExxonNuclearCompany(ENC)14x14fueledcoreexceptforfourWestinghouseMixedOxide(MOX)assemblies.R.E.GinnawaslastsuppliedwithWestinghousefuelduringthecycle7reload.Cycle14isthefirstcycleinatransitionphasefromENCtoWestinghouse14x149gridOptimizedFuelAssembly(OFA)fuelwithcoreloadingsrangingfromapproximatelya15:oOFAand85MENCfueledcoretoeventuallyanall-OFA-fueledcore.TheOFAfuelisverysimilartotheWestinghouse7grid14x14lowparasiticfuelwhichhashadsubstantialoperatingperformanceinanumberofnuclearplants.Thisreportsummarizesthesafetyevaluation/analysisfortheregion-by-regionreloadtransitionfromthepresentENC-fueledcoretoanall-WestinghouseOFA-fueledcore.ThisreportexaminesthedifferencesbetweentheOFAandENCfuelassemblydesignsandevaluatestheeffectofthesedifferencesonthecoresduringthetransitiontoanall-OFA-fueledcore.TheevaluationconsidersthestandardreloaddesignmethodsdescribedinReference1,andthetransitioneffectsdescribedinChapter18ofReference2.Reference3presentstheoperatingexperiencethroughDecember1981ofOFAdemonstrationassemblies.Therearefour14x147griddemonstrationassembliesthathavecompletedtwocyclesofoperation(establishedburnup-20,000MWD/MTU).Post-testexaminationatthecompletionofthefirstcycleofirradiationindicatednoabnormalities.However,onedemonstrationassemblyattheendofthesecondcycleofirradiationwasdamagedandremoved.ItwasconcludedthatthecauseofthedamagewasanisolatedeventandnotagenericOFAdesignproblem(seeLetterReportIT-83-222,"FailureInvestigationofPointBeachUnit2OFARods,"July1983).Thedemonstrationassemblieswillhaveexperiencedapproximately35,000MWD/MTUofburnupin1984.Sections3.0through6.0summarizetheMechanical,Nuclear,ThermalandHydraulic,andAccidentEvaluations,respectively.0710L:61"3

2.0SUMMARYANDCONCLUSIONSConsistentwiththeWestinghousestandardreloadmethodology(Reference1),parametersarechosentomaximizetheapplicabilityofthetransitionevaluationspresentedhereinforfuturecycles.TheobjectiveofsubseqventcyclespecificReloadSafetyEvaluationReports(RSE's)willbetoverifythatapplicablesafetylimitsaresatisfiedbasedonthereferenceevaluation/analysesestablishedbythisreport.Thetransitiondesignandsafetyevaluationspresentedhereinconsiderthefollowingnominaloperatingconditions:1520MWtcorepower,2250psiasystempressure,573.5'Fvesselaveragecoolanttemperature(HFP)at2250psia,and174,000gpmprimarysystemthermaldesignflow.Theresultsofevaluation/analysesandtestsdescribedhereinleadtothefollowingconclusions:1.TheWestinghouseOFAsaremechanicallyandhydraulicallycompatiblewiththeENCfuelassemblies,controlrods,andreactorinternalsinterfaces.AlldesigncriteriafortheWestinghouseOFA'saresatisfied.2.GenerallychangesinthenuclearcharacteristicsbecauseofthetransitionfromENCto,OFAfuelwillliewithinthecycle-to-cyclevariationsobservedforpastfuelreloaddesigns.Themoderatortemperaturecoefficientisthemostsignificantexceptiontothis.SincetheH/UratioislargerforOFA,themoderatortemperaturecoefficientismorepositivethanobservedinpastWestinghousefueledR.E.Ginnacores.Thishasbeenaccountedforintheaccidentevaluations.0710L:62-1 3.DemonstrationexperiencewithWestinghouseOFAscontainingZircaloygridsprovidesreasontoexpectsatisfactoryoperationfromOFAZircaloygrids.4.Theproposedtechnicalspecificationschanges(AttachmentA)areapplicabletocorescontaininganycombinationofOFAandENCfuelandplantoperatinglimitationswillbesatisfiedwiththeseproposedchanges.5.AreferenceisestablisheduponwhichtobasefuturecyclesafetyevaluationsforWestinghouseOFAreloadfuel.0710L:62-2 3.0MECHANICALEVALUATIONThemechanicaldesignrequirementsandcriteriaapprovedbytheNRCforthe17x17OFAdesignaredescribedinReference2.The14x14OFAdesignmeetsthesesamebasicdesignrequirementsandcriteria.ENC,inestablishingtheirassemblydesign,demonstratedtheirfuel'scompatibilitywiththeWestinghousedesignwhichwastheinitialR.E.Ginnafuel.WestinghousehasdemonstratedthecompatibilityofitsOFAdesignwithitsinitial9griddesignandhasperformedthereviewsdescribedbelowtherebydemonstratingcompatibilityoftheWestinghouseOFAandENCfuelassemblies.ThesimilaritiesbetweentheOFAdesignandpreviousWestinghousefuelincludethenumberoffuelrods,grids,guidethimblesandinstrumenta-tiontube.Thematerialsofthetopandbottomnozzles,fuelrod,andtopandbottomgridsarethesameinboththeWestinghouseOFAandinitialdesigns.Thedesignchangesbetweenthetwodesignsincludeareductioninfuelrod,guidethimble,andinstrumentationtubediameters,andchangeofmaterial(SStozirc)andsevenintermediategridsmadeofZircaloywiththethicknessandheightincreasedtoretaintherequiredgridstrength.Inadditiontothereductionofthefuelroddiameter,6.2inchesofnaturaluraniumpelletsreplacethestandardslightlyenrichedpelletsatbothendsofthefuelstack(axialblanket).Alsochangedisthebottomnozzlewhichincludesalockingcupfeaturewhichfacilitatesreconstitutabilityofthefuel.assembly.CThisisidenticaltothestandardbottomnozzleexceptforthereconstitutionfeature.Thisdesignchangeofthebottomnozzleandgridmodificationswereevaluatedanddeterminedtohavenoimpactonthesafeoperationoftheplantandtheperformanceofthefuel.Thesechangesweremadeasallowedpertherequirementsof10CFR50.59.ThefueldesignbasesandcriteriaforWestinghouse14x14OFA'sarethesamea0thosediscussedinSections4.2and4.4.1.2ofReference2fortheWestinghouse17x17OFAdesign.Verificationthatthesecriteriaare0710L:63-1

metforWestinghousefuelintheR.E.GinnaplantisperformedusingthedesignmethodologyandmodelsdiscussedinReference1.Animprovedthermalsafetymodel,Reference4,isbeingusedtogeneratefueltemperaturesforsafetyanalysis.ThetopandbottomgridsoftheOFAarefabricatedfromInconelandthesevenintermediategridsarefabricatedfromZircaloy.TheelevationofthecenterlineofeachoftheOFAgridsmatchthatoftheENCgridsinordertominimizecrossflowduringoperation.Figure1showstheOFA.TheZircaloygridheightis2.25inchesascomparedtotheInconelgridwhichis1.5inches.Thesedimensionalchangesweremadetocompensatefordifferencesinmaterialstrengthproperties.Eachfuelrodisgivensupportatsixcontactpointswithineachgridcellbyacombinationofsupportdimplesandsprings.TheWestinghouseOFAthimbletubesarefabricatedfromZircaloy.Therearetwosectionswithalargediameterandtwowithasmallerdiameter.Thelargerdiameteratthetoppermitsrapidcontrolrodinsertion.Bothofthereduceddiametersectionsproduceadashpotactionneartheendofthecontrolrodtraveltodeceleratethecontrolrodandreduceimpactforces.TheinstrumentationtubeisalsofabricatedfromZircaloy.Thistubeisofconstantdiameterandisdesignedtoaccept,theR.E.Ginnaincoreinstrumentation.TheOFAinstrumentationtubehasa0.004inchdiametralincreasewhencomparedtotheENCassemblyinstrumentationtube.ThereissufficientdiametralclearancefortheinstrumentationthimbletotraversetheOFAinstrumentationtube.TheOFAtopandbottomnozzlesarefabricatedfromstainlesssteel.Bothnozzlesindexthefuelassemblyinthecoreanddirectflowintoandoutoftheassemblythroughperforatednozzleplates.TheaxialspacingbetweenthetopandbottomnozzleisestablishedtoaccommodatethegrowthofthefuelrodsduetoirradiationeffectsontheZircaloyfueltube.TheOFAbottomnozzledesignhasareconstitutionfeaturewhichfacilitateseasyremovalofthenozzlefromthefuelassembly.0710L:e3-2 HolddownoftheOFAisprovidedbyfoursetsoftwoleafsprings.TheInconel,718springdesignpermitsbothahighspringrateandlargetravel,whichisrequiredtoaccommodatethedifferenceinthermalexpansionbetweenthe2ircaloythimblesandthestainlesssteelreactorinternals.Thisspringdesignalsoaccommodatesthegrowthofthe2ircaloythimblesduringserviceandpreventsfuelassemblyliftoffduringnormaloperation.ThefuelrodfrettingevaluationperformedontheWestinghouse14x14sevengridOFAdesignhasshownthatevenwithnogridspringforceactingonthefuelrodbythefiveZircaloygridsatendoflife,thecladwearcriterionismet.SincetheR.E.GinnaOFAdesigncontainsninegridsincludingsevenZircaloygrids,considerableadditionalwearmarginexistsfortheR.E.Ginnafueldesignthanfortheseven-gridOFAdesign.TherodbowbehavioroftheR.E.GinnaOFAisexpectedtobebetterthanthatofthe7gridWestinghousefuelassembly.TheR.E.GinnaOFAwillhavereducedgridspringforcesduetotheZircaloygridsshorterspanlengthsandahigherfueltubethickness-to-diameterratiothanthe7gridfuelassembly.Thesedesignchangesshouldresultinreducedrodbow.The-ZircalloygridspringforcesarelowerduringservicethanthosetypicallyusedonInconelgrids.Therefore,lowerfrictionforcesaregeneratedbythedifferentialthermalexpansionandirradiationgrowthofthefuelrods.Thisresultsinlowerloadsappliedtotheskeletoncomponentsthanarepresentinthe7gridWestinghouseassemblies.Theskeletoncomponentsare'conservativelydesignedtoaccepttheseloadswithmargin.0710L:63-3 e

Newthimble-pluggingdevicesandsecondarysourceassembliesweredesignedtobecompatiblewiththeOFA'sonly.Thesenewcorecomponentsweredesignedtoaccommodatethegrowthofthefuel'ssemblyandthedifferenceinthermal-.expansionbetweentheZircaloythimblesofthefuelassemblyandstainlesssteelreactorinternals.ThecontrolrodsusedintheR.E.GinnareactorcorearecompatiblewiththeOFA.Thecurrentthimblepluggingdevicesandsecondarysourceswillcontinuetobeusedwithpreviouslysuppliedfuel.0710L:63-4

~II~~

0 4.0NUCLEAREVALUATIONThekeysafetyparametersevaluatedfortheconceptualtransitionandfullOFAdesignsshowthattheexpectedrangesofvariationformanyoftheparameterswillliewithinthenormalcycle-to-cyclevariationsobservedforpastENCfuelreloaddesigns.Theparameterswhichfalloutsideoftheserangesarethosewhicharesensitivetofueltype,e.g.,themoderatortemperature-coefficient.Theaccidentevaluation,documentedinSection6.0,hasconsideredrangesofparameterswhichareappropriateforthetransitioncyclesandbeyond.ThemethodsandcoremodelsusedinthereloadtransitionanalysisareidenticaltothoseemployedanddescribedinReferences1,2,and5.ThesearethesamemethodsandmodelswhichhavebeenusedinotherWestinghousereloadcycledesigns.Nochangestothenucleardesignphilosophy,methods,ormodelsarenecessaryduetothetransitiontoOFAfuel.AnumberofchangestotheR.E.GinnaTechnicalSpecifications(AttachmentA)willbeproposedaspartofthetransitiontoOFAfuel.Someofthesechanges,whetherdirectlyrelatedtoOFAfuelornot,impactthecorenucleardesign.Thesechangesinclude:(1)thepositivemoderatortemperaturecoefficient(MTC)specification;and(2)the0.3multiplierintheFlimitfunction;(3)areductionintherequiredshutdownmargin(SDM)to1.8"hp.Powerdistributionsandpeakingfactorsareprimailyloading"pattern-dependent.Theusualmethods,suchasenrichmentvariationcanbeemployedinthetransitionandfullOFAcorestoensurecompliancewiththepeakingfactorTechnicalSpecifications.0710L'64-1

5.0THERMALANDHYDRAULICEVALUATIONHYDRAULICCOMPATIBILITYThehydrauliccharacteri'stiesofanENCfuelassemblywereevaluatedbyperformingtestsonaclean,unirradiated.ENCfuelassemblyattheR.E.GinnasiteusingtheWestinghouseFuelAssemblyCompatiblitySystems(FACTS)loop.AsimilartestwasconductedonacleanunirradiatedsevengridWestinghouseOFAinthesameloop.SincetheWestinghouseOFAdesignforR.E.GinnaisslightlydifferentfromtheregularsevengridOFAtested(twoextramixingvanegridsandaslightlyshorterfuelrodlength)theeffectofthesedesigndifferencesonthehydrauliccharacteristicsofthetestassemblywasaddressed.Theresultsshowedthatthenetmismatchinoverallcorelosscoefficientwaslessthanonepercent.Itwasthereforeconcludedthatthetwoassembliesarehydraulicallycompatible.CALCULATIONALMETHODSThecalculationalmethodsusedintheanalysisemploythreechangesfrommethodspresentlyemployedfortheR.E.Ginnathermal-hydraulicanalysis.Thesemethodsare:(1)theTHINCIVcomputercode,(2).theWRB-1DNBCorrelationfortheOFA,and(3)theImprovedThermalDesignProcedure(ITDP).TheTHINCIVprogramisusedtoperformthermal-hydrauliccalculations.TheTHINCIVcodecalculatescoolantdensity,massvelocity,enthalpy,voidfractions,staticpressure,andDNBRdistributionsalongflowchannelswithinareactorcoreunderallexpectedoperatingconditions.TheTHINCIVcodeisdescribedindetailinReferences8and9.0710L:6 Inthis.application,theWRB-1DNBCorrelation(Reference6)isemployedinthethermal-hydraulicdesignoftheWestinghouseOFA.TheWRB-1Correlation(References6and13)providesasignificantimprovementinCriticalHeatFlux(CHF)predictionsoverpreviousDNBcorrelati'ons.The17x17OFADNBtestsshowedthattheWRB-1Correlationcorrectlyaccountedforthegeometrychangesingoingfromthe17x170.374"rodODdesigntothe17x170.360"rodODdesign,andthatthedesignlimitof1.17w'asstillapplicable,Reference13.The14x14OFAdesigninvolvedverysimilargeometrychangesfromthe7grid14x14STDfueldesign,namely,thereductionoftherodODfrom0.422"to0.400"andtheincorporationofagriddesignwithanincreasedheightandstrapthicknessduetothechangefromInconeltoZircaloy.ConfirmatoryDNBtestsperformedonthe)4xl4OFAtypicalcellgeometryverifiedthattheWRB-1CorrelationaccuratelypredictedCHFvaluesforthisgeometrytypeandthatthedesignlimitof1.17wasstillappropriate.TheW-3DNBRCorrelation(Reference14and15)wasusedinthedesignoftheENCfuelassembly.AcorrelationlimitDNBRof1.30isapplicable.ThedesignmethodemployedtomeettheDNBdesignbasisistheITDP,Reference7.Uncertaintiesinplantoperatingparameters,nuclearandthermalparameters,andfuelfabricationparametersareconsideredstatisticallysuchthatthereisatleasta95percentprobabilitythattheminimumDNBRwillbegreaterthanorequaltoDNBRforthepeakpowerrod.PlantparameteruncertaintiesareusedtodeterminetheplantDNBRuncertainty.This--DNBR'ncertainty,combinedwiththeGNBR..l,imit,establishesadesign.DNBRvaluewhichmustbemetinplantsafetyanalyses.SincetheparameteruncertaintiesareconsideredindeterminingthedesignDNBRvalue,theplantsafetyanalysesareperformedusingvaluesofinputparameterswithoutuncertainties.Inaddition,thelimitDNBR-valuesareincreasedtovaluesdesignatedasthesafetyanalysi'slimitDNBR's.TheplantallowanceavailablebetweenthesafetyanalysislimitDNBRvaluesandthedesignlimitDNBRvalues0710L:65-2 isnotrequiredtomeetthedesignbasis.Theallowancewillbeusedforflexibilityinthedesignandoperationofthispl'ant.TheDNBRmarginisdefinedasSafetyanalysisDNBRvalue=1-MarginThetablebelowindicatestherelationshipbetweenthecorrelationlimitDNBR,designlimitDNBR,andthesafetyanalysislimitDNBRvaluesusedrsforthisdesign.W14x14OFATypicalThimbleENC14x14Typica1ThimbleCorrlelationLimitDesignLimitSafetyAnalysisLimit1.171.34.1.521.171.331.511.301.58'.62~1.301.50)1.54)ThemarginbetweenthedesignlimitandthesafetyanalysislimitDRBRismorethanenoughtooffsettherodbowpenaltyandthetransitioncorepenalty.RODBOWTheOFAforR.E.Ginnahasninegridsandanactivefuellengthof141.4inches.BasedonthecurrentNRCapprovedlicensingbasis,Reference16,thefractionalclosureatanygivenburnupfortheOFAforR.E.Ginnacanbecomparedtothatofthe7-gridassembly.ThereleventparametersformakingsuchacomparisonareL/I(L=span2lengthbetweengrids,I=fuelrodmomentofinertia)andtheinitial0710L:65-3 rod-to-rodgap.The1/IratioishigherfortheOFA,buttheinitialrod-to-rodgapisalsolarger,therefore,theseeffortsoffseteachother.Thefractionalclosureatanyburnupforthe9-gridWestinghouseOFAcanbeobtainedbydirectLscalingfromthatofthe7-gridassembly.Theresultsindicatedthatamaximumrodbowpenaltyof4.Z4DNBRisapplicablefortheR.E.GinnaOFA.SufficientmarginbetweenthesafetyanalysislimitDNBRandthedesignlimitDNBRhasbeenmaintainedtoaccommodatethispenaltyaswellasthetransitioncoreDNBpenalty.TheENCfuelassemblywouldbeexpectedtohavelessgapclosurethantheWestinghouseOFA,duetotheENCfuel'sthickercladdingasshowninReference17.Dataobtainedbyotherinvestigations,References18and19,showthatgapclosuresupto55%%uhavenomeasurableeffectonDNB.Therefore,noresultantrodbowDNBRpenaltyisrequiredforENCfuel.TRANSITIONCOREDNBMETHODOLOGYTheOFAhasalargerhydraulicdiameterandflowareacomparedtotheENCfuelassembly.Thus,ifitisassumedthatthesamemassflowexistsinanENCassemblyandanOFAandthatthereisnoallowanceforflowredistributiontooccur,theENCfuelassemblywillhaveahighervelocityintherodbundle.Thehighervelocity,togetherwiththelowervalueofrodbundlehydraulicdiameter,willcausetherodbundlepressuredroptobehigherintheENCfuelassembly.Thus,forthesamevalueofmassflowrateintoanadjacentsetofENCandOFA,theflowwouldhaveatendencytoredistributefromtheENCtotheOFAintherodbundleregion.Inthegriddedregions,however,theOFAhasahighervalueofmixingVanegridlosscoefficient.ThiswillinducelocalizedflowredistributionfromtheOFAtotheENCattheaxialzonesnearthemixingvanegridpositions.0710L:65"4

ThenetconsequenceofthisflowredistributiononDNBRisprimarilyduetotheeffectthisredistributionhasonthehotchannelmassvelocityandthelocalquality.DependingontheaxiallocationoftheminimumDNBR,aDNBpenaltycanbepostualtedoneithertypeoffuelassemblywhencomparedtoafullcoreofsimilarfuel.A2XtransitioncoreDNBpenalty,ontheWestinghouseOFAandalXDNBpenaltyontheENCfuelweredeterminedtobeapplicablebyanalyzingdifferentassemblyloadingpatternsatvariouscoreconditionsinamannerconsistentwithpreviouslyapprovedanalysis,Reference20.Thusthetransitioncoreswillbeanalyzedinthefollowingmanner:theENCfuelinatransitioncorewillbeanalyzedasafullcoreofENCfuelapplyinga1%DNBtransitioncorepenlty;andtheOFAfuelinatransitioncorewillbeanalyzedasfullcoreofOFAfuelapplyinga2XDNBtransitioncorepenalty.TheDNBmarginspreviouslydescribedfortheENCandOFAfuelaremorethanenoughtoaccomodatethetransitioncorepenaltyandtherodbowpenalty.0710L65-5 0

6.0ACCIDENTEVALUATIONThissectionaddressestheimpactonaccidentanalysesofthefollowingproposedchangesforR.E.Ginna.oOFAPositiveMTCF>HMultiplierChangeArevisedFSARChapter14giveninAttachmentBcontainsthedescriptions,methodology,resultsandconclusionforeachaccidentreanalyzed.OFATheprincipalmechanicaldesigncharacteristicoftheOFAdesignwhichcouldhaveaneffectonaccidentsisthesmallerfuelrod.Thisleadstoahigherfuelrodtemperature,surfaceheatflux,andaDNBpenalty.ThelargerhydraulicdiameterandlowercoolantflowvelocitycauseareductioninheattransferafterDNB.ThesmallerfuelrodalsoleadstoafasterheatuprateforseverereactivitytransientssuchasRodClusterControlAssembly(RCCA)ejection.Asaresultofthesmallerfuelrod,forthesamepowerlevel,theOFAdesignwillhavealowerDNBratiothantheinitialdesign.TheDNBpenaltywasoffsetfortheOFAcorethroughtheuseoftheWRB-1DNBCorrelation,Reference6,andtheITDP,Reference7.ThosetransientsimpactedbytheOFAdesignareshowninTable1.AdiscussionofLoss-of-CoolantAccidents(LOCA)isaddressedlaterinthissection.PositiveMTCThepresentR.E.GinnaTechnicalSpecificationsrequiretheMTCtobezeroornegativeatalltimeswhilethereactoriscritical.This0710L:66-1 requirementisoverlyrestrictive,sinceasmallpositivecoefficientatreducedpowerlevelscouldresultinasignificantincreaseinfuelcycleflexibility,butwouldhaveonlyaminoreffectonthesafetyanalysisoftheaccidenteventspresentedintheFSAR.TheproposedTechnicalSpecificationchange,giveninAttachmentA,allowsa+5pcm/FMTCbelow70percentofratedpower,changingtoa0pcm/'FMTCat70percentpowerandabove.Apower-leveldependentMTCwaschosentominimizetheeffectofthespecificationonpostulatedaccidentsathighpowerlevels.Moreover,asthepowerlevelisraised,theaveragecorewatertemperaturebecomeshigherasallowedbytheprogrammedaveragetemperaturefortheplant,tendingtomakethemoderatorcoefficientmorenegative.Also,theboronconcentrationcanbereducedasxenonbuildsintothecore.Thus,thereislessneedtoallowapositivecoefficientasfullpower'isapproached.Asfuelburnupisachieved,boronisfurtherreducedandtheMTCwillbecomenegativeovertheentireoperatingpowerrange.TheimpactofapositiveMTContheaccidentanalysespresentedinChapter14oftheR.E.GinnaFSAR,Reference10,hasbeenassessed.Thoseincidentswhichwerefoundtobesensitive,tominimumornear-zeromoderatorcoefficientswerereanalyzed.Ingeneral,theseincidentsarelimitedtotransientswhichcausereactorcoolanttemperaturetoincrease.Withtheexceptionsbelow,theanalysespresentedhereinwerebasedona+5pcm/~FMTC,whichwasassumedtoremainconstantforvariationsintemperature.Thebankwithdrawalfromsubcriticalandcontrolrodejectionanalysesarebasedonacoefficientwhichisatleast+5pcm/'Fatzeropowernominalaveragetemperature,andwhichbecomeslesspositiveforhighertemperatures.ThisisnecessarysincetheTWINKLEcomputercode,onwhichtheanalysisisbased,isadiffusion-theorycoderatherthanapoint-kineticsapproximationandthemoderatortemperaturefeedbackcannotbeartificiallyheldconstantwithtemperature.Forall0710L:66-2 accidentswhicharereanalyzed,theassumptionofapositiveMTCexistingatfullpowerisconservative,sinceasnotedinAttachmentA,theproposedTechnicalSpecificationrequiresthatthecoefficientbezeroornegativeatorabove70percentpower.Accidentsnotreanalyzedincludedthoseresultinginexcessiveheat.removalfromthereactorcoolantsystemforwhichalargenegativeMTCisconservative,andthoseforwhichheatupeffectsfollowingreactortripareinvestigated,whicharenotsensitivetothemoderatorcoefficient.F>HMultiplierChangeAproposedchangefromK=0.2toK=0.3inthefollowingequationfortheNuclearHotChannelFactor(FH)wasevaluatedwithregardtoNitseffectonaccidentanalyses:FhH-1.66[1.0+.3(1-P)3wherePisthefractionoffullpowerand.3isthepowercorrectionconstant.Theeffectonaccidentanalysesisthroughthecoresafetylimitsatveryhighpressureandlowpowerlevels.Sincethesteamgeneratorsafety,valvespreventtheplantfromreachingtheselimitingconditions,theprotectionsetpointsareunaffectedbythischange.Thechangesometimesimpactstheaxialoffsetenvelopesuch,thatthef(EI)changes.However,nocreditforthef(hI)protectionisassumedintheaccidentanalyses.Therefore,thesafetyanalysesarenotimpactedbytheproposedFmultiplierchange.0710L66"3

Non"LOCATheimpactof.theproposedchangesasidentifiedearlierinthissectionhasbeenassessedforthenon-LOCAasprovidedinChapter14oftheR.E.GinnaFSARgiveninAttachmentB.Thefollowingaccidentshave.beenreanalyzed:UncontrolledRCCABankWithdrawalFromaSubcriticalConditionUncontrolledRCCABankWithdrawalatPowerRCCADropChemicalandVolumeControlSystemMalfunctionStartupofanInactiveReactorCoolantLoopReductioninFeedwaterEnthalpyIncidentExcessiveLoadIncreaseIncidentLossofReactorCoolantFlow/LockedRotorLossofLossofExternalElectricalLoadNormalFeedwater/StationBlackoutRuptureofaSteamPipeRuptureofaControlRodMechanismHousing-RCCAEjectionForeachofthesafetycriteriaaccidentsanalyzed,itwasfoundthattheappropriatearemet.'areBreakLOCAThelargebreakLOCAanalysisforR.E.Ginna,applicabletotransitionandfullOFAcorecycles,wasreanalyzedduetothedifferencesbetweenENCandWestinghouseOFAdesigns.ThisanalysisisconsistentwiththemethodologyemployedinWCAP-9500,IReferenceCoreReort17x170timizedFuelAssembl.Thecurrentlyapproved1981largebreakEmergencyCoreCoolingSystem(ECCS)EvaluationModel,Reference11,wasutilizedforaspectrumofcoldlegbreaks.TherevisedPADFuelThermalSafetyModel,Reference4,generatedtheinitialfuelrodconditions.TheR.E.Ginnaanalysiswasperformedforanassumedsteamgeneratortubeplugginglevelof.12%.0710L:66-4 ArevisedFSARChapter14.3.2giveninAttachmentCcontainsafulldescriptionofthemethodsandassumptionsutilizedfortheWestinghouseOFAECCSLOCAanalysis,andtheresultsoftheanalyses.ThelargebreakOFALOCAanalysisforR.E.Ginnautilizingthecurrentlyapproved1981evaluationmodelresultedinaPCTof1833Fforthe0.4COLOCAcaseatatotalpeakingfactorof2.32.AdditionoftheUPIpenaltyof21FresultsinafinalPCTof1854'F.Thesmallimpactofcrossflowfortransitioncorecyclesisconservativelyevaluatedasatmosta4'FeffectontheWestinghousefuel,whichiseasilyaccommodatedinthemarginto10CFR50.46limits.SmallBreakLOCAThesmallbreakLOCAanalysisforR.E.GinnaapplicabletotransitionandfullOFAcorecycles,wasreanalyzedduetothedifferencesbetweenEHCandWestinghouseOFAdesigns.ThisisconsistentwiththemethodologyemployedinWCAP-9500.ThecurrentlyapprovedOctober1975smallbreakECCSevaluationmodelwasutilizedforaspectrumofcold-legbreaks,Reference12.TherevisedPADfuelthermalsafetymodelgeneratedtheintialfuelrodconditions.TherevisedFSARChapter14.3.1,giveninAttachmentC,containsafulldescripitionoftheanalysisandassumptionutilizedfortheWestinghouseOFAECCSLOCAanalysis.ThesmallbreakOFALOCAanalysisforR.E.Ginnautilizingthecurrentlyapproved1975SmallBreakEvaluationmodelresultedinaPCTof1092Fforthe6inchdiametercoldlegbreak.TheanalysisassumedtheworstsmallbreakpowershapeconsistentwithaLOCAFenvelopeof2.32atcoremidplaneqelevationand1.5atthetopofthecore.AnalysesshowthatthehighandlowheadportionsoftheECCS,togetherwiththeaccumulators,providesufficientcorefloodingtokeepthecalculatedPCTwellbelowtherequiredlimitsof10CFR50.46.AdequateprotectionisthereforeaffordedbytheECCSintheeventofasmallbreakLOCA.0710L:66-5 TABLE1FSARCHAPTER14ACCIDENTANALYSISSENSITIVITYTOPROPOSEDCHANGESAccidentsOFA+MTC1.UncontrolledRodWithdrawalfromaSubcriticalConditionFSARSection14.1.1..2.UncontrolledRCCAWith-drawalatPower.FSARSection14.1.2.3.RodClusterControlAssembly(RCCA)DropFSARSection14.1.4.4.ChemicalandVolumeControlSystemMal-functionFSARSection14.1.5.5.StartupofanInactiveReactorCoolantLoopFSARSection14.1.7.6.ReductioninFeedwaterEnthalpyIncidentFSARSection14.1.10.7~ExcessiveLoadIncreaseIncidentFSARSection14.1.11.0710L:66"6 TABLE1(Con't)FSARCHAPTER14ACCIDENTANALYSISSENSITIVITYTOPROPOSEDCHANGES(CONTINUED)AccidentsOFA+MTC8.LossofReactorCoolantFlowFSARSection14.1.6..9.LossofExternalElectricalLoadFSARSection14.1.8.10.LossofNormalFeed-waterFSARSection14.1.9.11.LossofAllACPowertotheStationAux-iliariesFSARSection14.4.12.12.RuptureofaSteamPipeFSARSection14.2.5.13.RuptureofaControlRodMechanismHousing-RCCAEjectionFSARSection14.2.6.14.LOCAFSARSection14.3.10710L:66"7 01'

7.0REFERENCES

1.Bordelon,F.M.,etal.,"WestinghouseReloadSafetyEvaluationMet'hodology,"WCAP-9272(Proprietary)andWCAP-9273(Non-Proprietary),March1978.2.Davidson,S.L.;Iorii,J.A.,"ReferenceCoreReport-17xl7OptimizedFuelAssembly,"WCAP-9500-A,May1982.3.Skaritka,J.;Iorii,J.A.,"OperationalExperiencewithWestinghouseCores,"WCAP-8183,Revision12,August1983.4.LetterfromE.P.Rahe(Westinghouse)toC.O.Thomas(NRC),NS-EPR-2673,"WestinghouseRevisedPADCodeThermalSafetyModel,"WCAP"8720,Addendum2,October27,1982,(Proprietary).5.Camden,T.M.,etal.,"PALADON-WestinghouseNodalComputerCode,"WCAP-9485A(Proprietary)andWCAP-9486A(Non-Proprietary),December1979,andSupplement1,September1981.6.Motley,F.E.,etal.,"NewWestinghouseCorrelationWRB-1ForPredictingCriticalHeatFluxInRodBundlesWithMixingVaneGrids,"WCAP-8762,July1976.7.Chelemer,H.,etal.,"ImprovedThermalDesignProcedure,"WCAP-8567,July1975.8.Chelemer,H.,etal.,"THINCIV-AnImprovedProgramforThermal-HydraulicAnalysisofRodBundleCores,"WCAP-7956,June1973.9.Hochreiter,L.E.,etal.,"ApplicationoftheTHINCIVProgramtoPWRDesign,"WCAP-8054,September1973.10.FinalSafetyAnalysisReport,R.EDGinnaNuclearPowerPlant,DocketNo.50-244.0710L:67-1

7.0REFERENCES

(Continued)11.Eicheldinger,C.,"WestinghouseECCSEvaluationModel,1981Version,"WCAP-9200-P-A(Proprietary),WCAP-9221-A(Non-Proprietary)Revision1,1981.12.Skwarek,R.J.;Johnson,W.J.;andMeyer,P.E.,"WestinghouseEmergencyCoreCoolingSystemSmallBreak,"October1975Model,WCAP-8970-P-A(Proprietary)andWCAP-8971-A(Non-proprietary),January1979.13.Davidson,S.L.;Iorii,J.A.(Eds.),"VerificationTestingandAnalysesofthe17xl7OptimizedFuelAssembly,"WCAP-9401-P-AandWCAP-9402,March1979.14.Tong,L.S.,"CriticalHeatFluxesinRodBundles,TwoPhaseFlowandHeatTransferinRodBundles,"AnnualASMEWinterMeeting,November1969,p.3146.15.Tong,L.S.,"BoilingCrisisandCriteriaHeatFlux,...,"AECOfficeofInformationServices,TID-25887,1972.16.LetterfromR.A.Clark(NRC)toW.G.CounsilNortheastNuclearEngineeringCompany,

Subject:

FuelSafetyEvaluationofMillstone,UnitNo.2BSR,NRCDocketNo.50-336.P17.LetterfromG.F.Owsley(ENC)toT.A.Ippolito(NRC),XN-75-32,Supplement1,"ComputationalProcedureforEvaluatingFuelRodBowing,"July17,1979.18.Markowski,etal.,"EffectofRodBowingonCHFinPWRFuelAssemblies,"ASMEpaper77-HT-91.0710L:67"2

7.0REFERENCES

(Continued)19.LetterfromJ.H.TaylortoS.A.Varga,"StatusReportonREDProgramsdescribedinSemi-AnnualTopicalReportBAW-10097A,"Revision2,November13,1978.20.LetterfromC.0.Thomas(NRC)toE.P.Rahe(Westinghouse),"SupplementalAcceptanceNumber2forReferencingofLicensingTopicalReportsWCAP-9500andWCAPs9401/9402,"January24,1983.0710L:67-3 ATTACHMENTAAlistoftheTechnicalSpecificationchangesrequiredbvtheuseoftheOFAdesignandapositiveMTCisprovidedasAttachmentAtotheApplicationforAmendmenttoOperatingLicense.

0 ATTACHMENTBNON-LOCAACCIDENTANALYSISRESULTSFSARCHAPTER140710L6

ATTACHMENTBNON-LOCASAFETYANALYSISPresentedinAttachmentBarethosenon-LOCAaccidentanalysesoftheR.E.GinnaFSARChapter14impactedbytheproposedchangesasdeterminedinSection5.Providedbelowisadiscussionofinitialconditions,assumptions,andcomputer'codesusedtoanalyzetheaccidentspresented.Furtherdiscussionisprovidedforeachindividualanalysis.SectionnumbersinthisappendixcorrespondtothoseusedintheFSAR.B-10710L:6

~J TABLEOFCONTENTSSectionDescriptionPage14.0AccidentAnalysis14-114.1.1UncontrolledRCCAWithdrawalFromASubcriticalCondition14.1.1-114.1.2UncontrolledRCCAWithdrawalAtPower14.1.2-114.1.4RodClusterControlAssembly(RCCA)Drop14.1.4-114.1.5ChemicalandVolumeControlSystemMalfunction14.1.5-114.1.6LossofReactorCoolantFlow14.1.6-114.1.8~~LossofExternalElectricalLoad14.1.8"114.1.10ExcessiveHeatRemovalDueToFeedwaterTemperatureDecrease14.1.10-114.1.11ExcessiveLoadIncreaseIncident14.1.11-114.2.5RuptureofaSteamPipe14.2.5-114.2.6RuptureofaControlRodMechanismHousing-RCCAEjection14.2.6-10710L:6

,4 LISTOFTABLESTableDescriptionPage14"1SummaryofInitialConditionsandComputerCodesUsed14-2NominalVa1uesofPertinentPlantParametersforNon-LOCAAccidentAnalysis14"1214"3TripPointsandTimeDelaystoTripAssumedinAccidentAnalysis14-1314-4DeterminationofMaximumOverpowerTripPoint-PowerRangeNeutronFluxChannel-BasedonNominalS'etpointConsideringInherentInstrumentErrors14-1514.1.1-1Time'SequenceofEventsforUncontrolledRCCAWithdrawalFromaSubcriticalCondition14.1.2-1TimeSequenceofEventsforUncontrolledRCCAWithdrawalatPower14.1.2-814.1.6"1TimeSequenceofEventsforLossofReactorCoolantFlow14.1.6"1014.1.6"2.SummaryofLimitingResultsforLockedRotorAccident14.1.6-1114F1.6-3TimeSequenceofEventsforLockedRotorIncident14.1.6-120710L:6 LISTOFTABLES(continued)TableDescriptionPage14.1.8"1TimeSequenceofEventsforLossofExternalElectricalLoad14.1'-614.1~11-1TimeSequenceofEventsforExcessiveLoadIncreaseIncident14.1.11"414.2.5-1TimeSequenceofEventsforSteamlineRupture14.2.5-914.2.6"1ParametersUsedintheAnalysisoftheRodClusterControlAssemblyEjectionAccident14.2.6-1414.2.6"2TimeSequenceofEventsRCCAEjection14.2.6-150710L:6 LISTOFFIGURESFigureDescriptionPage14-1CoreLimitsandOverpower-OvertemperaturehTSetpoints14-17.14.2ReactivityCoefficientsUsedinNon-LOCASafetyAnalysis14-1814-3ReactivityInsertionSCRAMCurvesUncontrolledRCCABankWithdrawalFromSubcritical14.F1-914.1.1-2UncontrolledRCCABankWithdrawalFromSubcritical14.1.1-1014.1.2-1UncontrolledRCCABankWithdrawalAtPower,MaximumFeedback,100%Power,90pcm/sec14'.2-914.1.2-2UncontrolledRCCABankWithdrawalatPower,MaximumFeedback,100ÃPower,90pcm/sec14.1.2-1014.1.2-3UncontrolledRCCABankWithdrawalatPower,MaximumFeedback,1005Power,90pcm/sec14.1.2-1114.1.2-4UncontrolledRCCABankWithdrawalatPower,MaximumFeedback,1005Power,7pcm/sec14.1.2-12iv0710L:6 LISTOFFIGURES(continued)FigureDescriptionPage14.1.2-5UncontrolledRCCABankWithdrawalatPower,MaximumFeedback,1005Power,7pcm/sec14.1.2"1314.1.2-6UncontrolledRCCABankWithdrawalatPower,MaximumFeedback;10P%%dPower,7pcm/sec14.1.2-1414.1.2"7UncontrolledBankWithdrawalFrom100KPower14.1.2"1514.1.2-8UncontrolledBankWithdrawalFrom60%Power14.1.2-1614.1.2-9UncontrolledBankWithdrawalFrom10/Power14.1.2"1714.1.4-1DroppedRod-100pcm14.1.4-414.1.4-2DroppedRod-100pcm14.1.4-514.1.4-3.Dropped'od"100pcm14.1.4-614.1.4-4DroppedRod-800pcm14.1.4"714.1.4"5DroppedRod-800pcm14.1.4-814.1.4-6DroppedRod-800pcm14.1.4-90710L:6 LISTOFFIGURES(continued)FigureDescriptionPage14.1.6-1FullLossofFlow14.1.6-1314.1.6"2FullLossofFlow14.1~6-1414.1.6-3FullLossofFlow14.1.6-1514.1.6-4PartialLossofFlow14.1.6-1614.1.6-5PartialLossofFlow14.1.6-1714.1.6-6PartialLossofFlow14.1.6-1814.1.6-7PartialLossofFlow14.1.6-1914.1.6"8LockedRotor14.1.6"2014.1.6-9,LockedRotor14.1.6-2114.1.6-10LockedRotor14.1.6-2214.1.8"1LossofLoad-MinimumFeedbackWithAutomaticPressureControl14.1.8"914.1.8-2LossofLoad-MinimumFeedbackWithAutomaticPressureControl14.1.8-1014.1.8-3LossofLoad-MinimumFeedbackWithAutomaticPressureControl14.1'-11vi0710L:6 LISTOFFIGURES(continued)FigureDescriptionPage14.1.8"4LossofLoad-MaximumFeedbackWithAutomaticPressureControl14.1.8-1214.).8-5LossofLoad-MaximumFeedbackWithAutomaticPressureControl14.1.8-1314.1.8-6LossofLoad-MaximumFeedbackWithAutomaticPressureControl14.1.8-1414.1.8-7LossofLoad-MinimumFeedbackWithoutPressureControl14.1.8-1514.1.8-8LossofLoad-MinimumFeedbackWithoutPressureControl14.1.8-1614.1.8-9LossofLoad-MinimumFeedbackWithoutPressureControl14.1.8-1714.1.8"10LossofLoad-MaximumFeedbackWithoutPressureControl14.1'-1814.1.8-11LossofLoad-MaximumFeedback.WithoutPressureControl14.1.8-1914.1.8-12LossofLoad-MaximumFeedbackWithoutPressureControl14.1.8"20vii0710L:6 LISTOFFIGURES(continued)FigureDescriptionPage14.1.10-1FeedwaterEnthalpyDecrease-AutomaticRodControl14.1.10-514.1.10-2FeedwaterEnthalpyDecrease-AutomaticRodControl14.1.10-614.1.10-3FeedwaterEnthalpyDecrease-AutomaticRodControl14.1.10"714.1.10-4FeedwaterEnthalpyDecrease-ManualRodControl14.1.10"814.1.10"5FeedwaterEnthalpyDecrease-ManualRodControl14.1.10-914.1.10"6FeedwaterEnthalpyDecrease-ManualRodControl14.1.10"1014.1.11"1ExcessLoadIncrease"MinimumFeedbackWithoutRodControl14.1.11-514.1.11-2ExcessLoadIncrease-MinimumFeedbackWithoutRodControl14.1.11-614.1.11-3ExcessLoadIncrease-MinimumFeedbackWithoutRodControl14.1.11-7viii0710L:6 LISTOFFIGURES(continued)FigureDescriptionPage14.1.11-4ExcessLoadIncrease-MaximumFeedbackWithoutRodControl14.1.11-814.1.11"5ExcessLoadIncrease-MaximumFeedbackWithoutRodControl14.1.11-914.1.11-6ExcessLoadIncrease"MaximumFeedbackWithoutRodControl14.1.11-1014.1.11-7ExcessLoadIncrease-MinimumFeedbackWithAutomaticRodControl14.1.11-1114.1.11-8ExcessLoadIncrease-MinimumFeedbackWithAutomaticRodControl14.1.11-1214.1.11"9ExcessLoadIncrease-MinimumFeedbackWithAutomaticRodControl14.1.11-1314.1.11-10ExcessLoadIncrease-MaximumFeedbackWithAutomaticRodControl14.).11-1414.1.11-11ExcessLoadIncrease-MaximumFeedbackWithAutomaticRodControl14.1.11-1514.1.11-12ExcessLoadIncrease-MaximumFeedbackWithAutomaticRodControl14.1.11-1614.2.5"1SteamlineRupture14.2.5-11ix0710L:6 LISTOFFIGURES(continued)FigureDescriptionPage14.2.5"2SteamlineRupture14.2.5"1234.2.5"3SteamlineRupture-4.6ftBreakWithPower2LoopsinService14.2.5-1314.2.5-4SteamlineRupture-4.6ft2BreakWithPower2LoopsinService14.2.5-1414.2.5"5SteamlineRupture-4.6ft2BreakWithPower14.2.5-1514.2.5-6SteamlineRupture-4.6ft.2BreakWithPower14.2.5-1614..2.5"7SteamlineRupture-4.6ft2BreakWithPower14.2.5-1714.2.5-8SteamlineRupture-BreakWithoutPower4.6ft,2LoopsinService14.2.5-1814.2.5-9SteamlineRupture-4.6ft2BreakWithoutPower2LoopsinService14.2.5-1914.2.5-10SteamlineRupture-4.6ft2BreakWithoutPower2LoopsinService'4.2.5-2014.2.5-11SteamlineRupture-4.6ft2BreakWithoutPower2LoopsinService14.2.5-210710L:6 LISTOFFIGURES(continued)FigureDescriptionPage14.2.5-12SteamlineRupture-4.6ftBreakWithoutPower14.2.5"2214.2.5-13SteamlineRupture-FailedSafetyValve14.2.5-2314.2.5-14SteamlineRupture-FailedSafetyValve2LoopsinService14.2.5-2414.2.5-15SteamlineRupture-FailedSafetyValve2LoopsinService14.2.5-2514.2.5-16SteamlineRupture-FailedSafetyValve14.2.5-2614.2.5-17SteamlineRupture-FailedSafetyValve14.2.5-2714.2'-18SteamlineRupture-4.6ftBreakWithPowerOneLoopinService14.2.5-2814.2.5"19SteamlineRupture-4.6ft2BreakWithPowerOneLoopinService14.2.5-2914.2.5-20SteamlineRupture-4.6ft2BreakWithPower'neLoopinService14.2.5-3014.2.5-21SteamlineRupture-4.6ft2BreakWithPowerOneLoopinService14.2.5"3114.2.5-22SteamlineRuptureBreakWithPowerOneLoopinService14.2.5"32xi0710L:6 LISTOFFIGURES(continued)FigureDescriptionPage14.2.5-23SteamlineRuptureFailedSafetyValveOneLoopinService14.2.5-3314.2.5-24SteamlineRuptureFailedSafetyValveOneLoopinService14.2.5-3414.2.5-25SteamlineRuptureFailedSafetyValveOneLoopinService14.2.5-3514.2.5"26SteamlineRuptureFailedSafetyValveOneLoopinSevice14.2.5-3614.2.6-.1RCCAEjection-BeginningofLife,FullPower14.2.6-1614.2.6-2RCCAEjection-BeginningofLife,ZeroPower14.2.6-170710L:6X11

~Chater14InitialConditionsFormostaccidentswhichareDNB-limited,nominalvaluesofinitialconditionsareassumed.Theallowancesonpower,temperature,andpressurearedeterminedonastatisticalbasisandareincludedinthelimitDNBR,asdescribedinWCAP-8567(Reference1).Thisprocedureisknownasthe"ImprovedThermalDesignProcedure,"andisdiscussedmorefullyinSection4.ForaccidentswhicharenotDNB-limitedorinwhichtheImprovedThermalDesignProcedureisnotemployed,theinitialconditionsareobtainedbyaddingthemaximumsteadystateerrorstoratedvalues.Thefollowingconservativesteadystateerrorswereassumedintheanalysis:1.CorePower+2percentallowanceforcalorimetricerror2.AverageReactorCoolant+4oFallowanceforcontrollerdeadbandandmeasurementerror.3.PressurizerPressure+30poundspersquareinch(psi)allowanceforsteadystatefluctuationsandmeasurementerrorTables14-1and14"2summarizeinitialconditions'andcomputercodesusedintheaccidentanalysis,andshowwhichaccidentsemployedaDNBanalysisusingtheImprovedThermalDesignProcedure.0710L:614-1

PowerDistributionThetransientresponseofthereactorsystemisdependentontheinitialpowerdistribution.Thenucleardesignofthereactorcoreminimizesadversepowerdistributionthroughtheplacementofcontrolrodsandroperatinginstructions.Theconstantaxialoffsetcontrol(CAOC)strategyisusedforR.E.Ginna.Powerdistributionmaybecharacterizedbytheradialfactor(F)andthetotalpeakingaHfactor(F~).ThepeakingfactorlimitsaregivenintheTechnicalSpecificationsandinSection5.0ofthisreport.FortransientswhichmaybeDNB-limited,theradialpeakingfactorisofimportance.Theradialpeakingfactorincreaseswithdecreasingpowerlevelduetorodinsertion.ThisincreaseinFHisincludedintheaHcorelimitsillustratedinFigure14-1.AlltransientsthatmaybeDNBlimitedareassumedtobeginwithaF>Hconsistentwiththeinitial,powerleveldefinedintheTechnicalSpecifications.TheaxialpowershapeusedintheDNBcalculationsarediscussedinSection4.TheradialandaxialpowerdistributionsdescribedaboveareinputtotheTHINGCodeasdescribedinSection4.Fortransientswhichmaybeoverpowerlimited,thetotalpeakingfactor(F~)isofimportance.AlltransientsthatmaybeoverpowerlimitedareassumedtobeginwithplantconditionsincludingpowerdistributionswhichareconsistentwithreactoroperationasdefinedintheTechnicalSpecifications.Foroverpower,transientswhichareslowwithrespecttothefuelrodthermaltimeconstant,forexample,theChemicalandVolumeControlSystemmalfunctionthatresultsinadecreaseintheboronconcentrationinthereactorcoolantincidentwhichlastsmanyminutes,andtheexcessiveincreaseinsecondarysteamflowincidentwhichmayreachequilbriumwithoutcausingareactortrip,.thefuelrodtherm'alevalua-tionsareperformedasdiscussedinSection4.Foroverpowertransients0710L:614"2 whicharefastwithrespecttothefuelrodthermaltimeconstant,forexample,theuncontrolledrodclustercontrolassemblybankwithdrawalfromsubcriticalandrodclustercontrolassemblyejectionincidentswhichresultinalargepowerriseoverafewseconds,adetailedfuelheattransfercalculationmustbeperformed.Althoughthefuelrodthermaltimeconstantisafunctionofsystemconditions,fuelburnupandrodpower,atypicalvalueatbeginning-of-lifeforhighpowerrodsisapproximatelyfiveseconds.h.ReactivitCoefficientsAssumedintheAccidentAnalsesPThetransientresponseofthereactorsystemisdependentonreactivityfeedbackeffects,inparticularthemoderatortemperaturecoefficientandtheDopplerpowercoefficient.ThesereactivitycoefficientsandtheirvaluesarediscussedindetailinSection3.0ofthemaintext.Intheanalysisofcertainevents,conservatismrequirestheuseoflargereactivitycoefficientvalues,whereasintheanalysisofotherevents,conservatismrequirestheuseofsmallreactivitycoefficientvalues.SomeanalysessuchaslossofcoolantfromcracksorrupturesintheReactorCoolantSystemdonotdependonreactivityfeedbackeffects.Thejustificationforuseofconservativelylargeversussmallreactivitycoefficientvaluesistreatedonanevent-by"eventbasis.Insomecasesconservativecombinationsofparametersareusedtoboundtheeffectsofcorelife,althoughthesecombinationsmaynotrepresentpossiblerealisticsituations.ThelimitingvaluesofthemoderatordensityandDopplerpowercoefficientsusedinthesafetyanalysesareshowninFigure14-2.RodClustersControlAssemblInsertionCharacteristicsThenegativereactivityinsertionfollowingareactortripisafunctionofthepositionversustimeoftherodclustercontrolassembliesandthevariationinrodworthas.afunctionofrodposition.Withrespecttoaccidentanalyses,thecriticalparameteristhetimeofinsertionup'tothedashpotentry.0710L:614-3 TherodclustercontrolassemblypositionversustimeassumedinaccidentanalysesisshowninFigure14-3.Therodclustercontrolassemblyinsertiontimetodashpotentryisnormalizedto1.8seconds.Figure14-3alsoshowsthefractionoftotalnegativereactivityinsertionversusnormalizedrodposition.Thiscurveisusedtocomputethenegativereactivityinsertionversustimefollowingareactortrip.Atotalnegativereactivityinsertionfollowingatripof4percenthkisassumedinthetransientanalysesexceptwherespecificallynotedotherwise.Thisassumptionisconservativewithrespecttothecalculatedtripreactivityworthavailable.TriPointsandTimeDelastoTriAssumedtoAccidentAnalsesAreactortripsignalactstoopentwotripbreakersconnectedinseriesfeedingpowertothecontrolroddrivemechanisms.Thelossofpowertothemechanismcoilscausesthemechanismstoreleasetherodclustercontrolassemblieswhichthenfallbygravityintothecore.Therearevariousinstrumentationdelaysassociatedwitheachtripfunction,includingdelaysinsignalactuation,inopeningthetripbreakers,andinthereleaseoftherodsbythemechanisms.Thetotaldelaytotripisdefinedasthetimedelayfromthetimethattripconditionsarereachedtothetimetherodsarefreeandbegintofall.Limitingtripsetpointsassumedinaccidentanalysesandthetimedelayassumedforeachtrip'unctionaregiveninTable14-3.ReferenceismadeinthattabletoOvertemperatureandOverpowerhTtripshowninFigure14-1.ThisfigurepresentstheallowableReactorCoolantLoopAverageTemperatureandhTforthedesignflowandpowerdistribution,asdescribedinSection4,asafunctionofprimarycoolantpressure.TheboundariesofoperationdefinedbytheoverpowerhTtripandtheovertemperaturehTtriparerepresentedas"ProtectionLines"onthisdiagram.Theprotectionlinesaredrawnto0710L:614-4

includealladverseinstrumentationandsetpointerrorssothatundernominalconditionstripwouldoccurwellwithintheareaboundedbytheselines.TheutilityofthisdiagramisthatthelimitimposedbyanygivenDNBRcanberepresentedasaline.TheDNBlinesrepresentthelocusofconditionsforwhichtheDNBRequalsthelimjtvalue.ThelimitvaluesforWestinghousefuel.are1.52(typicalcell)and1.51(thimblecell).ForEXXONfuel,thevaluesare1.62(typicalcell)and..1.54(thimblecell).AllpointsbelowandtotheleftofaDNBlineforagivenpressurehaveaONBRgreaterthanthelimitvalue.ThediagramshowsthatDNBispreventedforallcases,iftheareaenclosedwiththemaximumprotectionlinesisnottraversedbytheapplicableONBRlineatanypoint.Theareaofpermissibleoperation(power,pressure,andtemperature)isboundedbythecombinationofreactortrips:highneutronflux(fixedsetpoint);highpressure(fixedsetpoint);lowpressure(fixedset-point);overpowerandovertemperaturehT(variablesetpoints).Thelimitvalue,whichwasusedastheONBRlimitforallaccidentsanalyzedwiththeImprovedThermalDesignProcedure(seeTable14-1),isconservativecomparedtotheactualdesignDNBRvaluerequiredtomeettheONBdesignbasisasdiscussedinSection4.Thedifferencebetweenthelimitingtrippointassumedfortheanalysisandthenormaltrippointrepresentsanallowanceforinstrumentationchannelerrorandsetpointerror../NominaltripsetpointsarespecifiedintheplantTechnicalSpecifications.InstrumentationDriftandCalorimetricErrors-PowerRaneNeutronFluxTheinstrumentationdriftandcalorimetricerrorsusedinestablishingthepowerrangehigh'eutronfluxsetpointarepresentedinTable14-4.Thecalorimetricerroristheerrorassumedinthedeterminationofcore'tthermalpowerasobtainedfromsecondaryplantmeasurements.Thetotalionchambercurrent(sumofthetopandbottomsections)iscalibrated(setequal)tothismeasuredpoweronaperiodicbasis.0710L:614"5 Thesecondarypowerisobtainedfrommeasurementoffeedwaterflow,feedwaterinlettemperaturetothesteamgeneratorsandsteampressure.High-accuracyinstrumentationisprovidedforthesemeasurementswithaccuracytolerancesmuchtighterthanthosewhichwouldberequiredtocontrolfeedwaterflow.ComuterCodesUtilizedSummariesofsomeoftheprincipalcomputercodesusedintransientanalysesaregivenbelow.ThecodesusedintheanalysesofeachtransienthavebeenlistedinTable14-1.FACTRANFACTRANcalculatesthetransienttemperaturedistributioninacrosssectionofmetalcladU02fuelrodandthetransientheatfluxatthesurfaceofthecladusingasinputthenuclearpowerandtime-dependentcoolantparameters(pressure,flow,temperature,anddensity).Thecodeusesafuelmodelwhichexhibitsthefollowingfeaturessimultaneously:l.Asufficientlylargenumberofradialspaceincrementstohandlefasttransientssuchasrodejectionaccidents.2.Materialpropertieswhicharefunctionsoftemperatureandasophisticatedfuel-to-cladgapheattransfercalculation.3.Thenecessarycalculationstohandlepost-DNBtransients:filmboilingheattransfercorrelations,Zircaloy-waterreaction,andpartialmeltingofthematerials.0710L:614"6 FACTRANisfurtherdiscussedinReference2.LOFTRANTheLOFTRANprogramisusedforstudiesoftransientresponseofaPWRsystemtospecifiedperturbationsinprocessparameters.LOFTRANsimulatesamultiloopsystembyamodelcontainingreactorvessel,hot-andcold-legpiping,steamgenerator(tubeandshellsides)andthepressurizer.Thepressurizerheaters,spray,relief,andsafetyvalvesarealsoconsideredintheprogram.Pointmodelneutronkinetics,andreactivityeffectsofthemoderator,fuel,boron,androdsareincluded.Thesecondarysideofthesteamgeneratorutilizesahomogeneous,saturatedmixtureforthethermaltransientsandawater-levelcorrelationforindicationandcontrol.TheReactorProtectionSystemissimulatedtoincludereactortripsonhighneutronflux,OvertemperaturebT,OverpowerhT,highandlowpressure,lowflow,andhighpressurizerlevel.Controlsystemsarealsosimulatedincludingrodcontrol,steamdump,feedwatercontrol,andpressurizerpressurecontrol.TheEmergencyCoreCoolingSystem,includingtheaccumulatorsandupper-headinjection,isalsomodeled.LOFTRANisaversatileprogramwhichissuitedtobothaccidentevalua-tionandcontrolstudiesaswellasparametersizing.LOFTRANalsohasthecapabilityofcalculatingthetransientvalueofDNBRbasedontheinputfromthecorelimitsillustratedinFigure14-1~ThecorelimitsrepresenttheminimumvalueofDNBRascalculatedfortypicalorthimblecell.LOFTRANisfurtherdiscussedinReference3.0710L:614-7

TWINKLETheTWINKLEprogramisamulti-dimensionalspatialneutronkineticscode.Thecodeusesanimplicitfinite-differencemethodtosolvethetwo"grouptransientneutrondiffusionequationsinone,two,andthreedimensions.Thecodeusessixdelayedneutrongroupsandcontainsadetailedmulti-regionfuel-clad-coolantheattransfermodelforcalculatingpointwiseDopplerandmoderatorfeedbackeffects.Thecodehandlesupto2000spatialpoints,andperformsitsownsteadystateinitialization.Asidefrombasiccross-sectiondataandthermal-hydraulicparameters,thecodeacceptsasinputbasicdrivingfunctionssuchasinlettemperature,pressure,flow,boronconcentration,controlrodmotion,andothers.Variouseditsareprovided,e.g.,channelwisepower',axialoffset,enthalpy,volumetricsurge,pointwisepower,andfueltemperatures.TheTWINKLECodeisusedtopredictthekineticbehaviorofareactorfortransientswhichcauseamajorperturbationinthespatialneutronfluxdistribution.TWINKLEisfurtherdiscussedinReference4.THINCTheTHINGCodeisdescribedinReferences18and19,(maintext).References1.Chelemer,H.,etal.,"ImprovedThermalOesignProcedure,"WCAP-8567-P(Proprietary),July,1975,andWCAP-8568(Non-Proprietary),July1975.2.Hargrove,H.G.,"FACTRAN-AFortran-IVCodeforThermalTransientsinaUOFuelRod,"WCAP-7908,June1972.II0710L:6 3.Burnett,T.W.T.,etal.,"LOFTRANCodeDescription,"WCAP-7907,June1972.4.Risher,D.H.,Jr.;Barry,R.F.,"TWINKLE"AMulti-DimensionalNeutronKineticsComputerCode,"WCAP-7979-P-A(Proprietary),andWCAP-8028-A(Non-Proprietary),January1975.0710L614-9

aTABI.E14"1SUMMAIIYOFINITIALCONOITIOITSINOCOIIPUTERCODESUSEDAccidentsimprovedThermaIComputerDNB"DesignCodesUtilizedCorrelationProcedureInitiaINSSSTIEermaIPowerOutput(NWT)ReactorVesselCoolantFlow(GPH)VesselAveragoTemp(oF)PressurizerPressure(psia)UncorltrolledRCCATWINKLEWithdrawalfromaFACTRANSubcriticaITHINGConditionWRB-IH-3Yes824325472250UncontroIledRCCALOFTRANWithdrawalatPowerHRB-IW-3Yes1520912152179200573.5562.9549.72250RodClusterLOFTRANControlAssemblyTHING(RCCA)DropWRB-1H-3Yes1520179200573'2250.ChemlcaIandNAVolumeControISysternHaIfunctIon0and1520~NANANAReductioninFeedwaterEnthaIpyLOFTRANWRB"IW-3Yes0and1520179200547573.52250ExcessiveLoadLOFTRANIncr'easeWRB-IW-3Yes1520179200573'2250LossofLoadTurbineTripLOFTRANWRB-1W-3Yes1520179200573.52250SteamllneBreakLOFTRANTHINGW-3No174000800405472250"WheretwocorrelationsaroIisted,HRB-IappliostoWestinghousefuelH-3appliestoEXXONfuel<<<<OnepumpInoporation.AccountsforreverseI'lowthroughotherloop.0710L:6

TABLE,14-1(Continued)SUHHARYOFIITIALCODITIONSA0COHPUTERCODESUSEDAccidentsImprovedThermaIComputerDNBDesignCodesUtilizedCorrelationProcedureInitlaIReactorNSSSThermaIVesselVesselPowerCoolantAveragePressurizerOutput(HWT)Flow(GPH)Temp.(4F)Pressure(psia)LossofFlowLOFTRANFACTRANTHINGWRB-1W-3Yes1520179200573.52250LockedRotorLOFTRANFACTRANN/ANo1550174000577.52280JRodEJectlon.TWINKLEFACTRANN/ANo1550and017400080040>>"547andN/A573.5+onepumpInoporation.Accountsforreversoflowthroughotherloop.0710L:6

0TABLE14-2NOMINALVALUESOFPERTINENTPLANTPARAMETERSFORNON-LOCAACCIDENTSANALYSIS"ParameterWithITDPWithoutITDPThermalOutputofNSSS(MWt)g1520/1520CoreInletTemperature(~F)543.7543.7VesselAverageTemperature('F)573.5573.5ReactorCoolantSystem*Pressure(psia)22502250ReactorCoolantFlowPerLoop(gpm)TotalReactorCoolantFlow(10LBM/hr)8960067.98700065.9Al(g~<SteamFlowfromNSSS(10LBM/hr)6.586.58SteamPressureatSteamGenerator746.5Outlet(psia)IAssumed,FeedwaterTemperatureat432.3SteamGeneratorInlet(F)746.5432.3AverageCoreHeatFlux(BTU/hr-ft)21894401894400Thenon-LOCAanalysesassumeasteamgeneratortubeplugginglevelof10;~.0710L:614-12 TABLE14"3TRIPPOINTSANDTIMEDELAYSTOTRIPASSUMEDINACCIDENTANALYSESTripFunctionLimitingTripPointAssumedInAnalsisTimeDelaysSecondsPowerrangehignneutron/flux,highsetting118K0.5Powerrangehighneutronflux,lowsetting35K0.5OvertemperaturehTVariableseeFigure14-16.0OverpowerhTVariableseeFigure14-12.0Highpressurizerpressure2425psia2.0Lowpressurizerpressure1775psia2.0aTotaltimedelay(includingRTDtimeresponse,andtripcircuit,channelelectronicsdelay)fromthetimethetemperaturedifferenceinthecoolantloopsexceedsthetripsetpointuntiltherodsarefreetofa11.0710L:614-13 TABLE14-3(Continued)TRIPPOINTSANDTIMEDELAYSTOTRIPASSUMEDINACCIDENTANALYSESTripFunctionLimitingTrip.PointAssumed~*'TimeDelaysSecondsLowreactorcoolantflow875loopflow(Fromloopflowdetectors)1.0UndervoltagetripNotapplicable1.5TurbinetripNotapplicable2.0Low-lowsteamgenerator.level0~ofnarrowrangelevelspan2.00710L:614-14 TABLE14-4DETERMINATIONOFMAXIMUMOVERPOWERTRIPPOINT"POWERRANGENEUTRONFLUXCHANNEL-BASEDONNOMINALSETPOINTCONSIDERINGINHERENTINSTRUMENTERRORSVariableAccuracyofMeasurementofVariableIerrorEffectOnThermalPowerDetermination~error(Estimated)(Assumed)'CalorimetricErrorsintheMeasurementofSecondarySystemThermalPower:Feedwatertemperature+0.5Feedwaterpressure(smallcorrectiononenthalpy)+0.50.3Steampressure(smallcorrectiononenthalpy)Feedwaterflow+1.251.25AssumedCalorimetricError(Xofratedpower)+2(a)AxialpowerdistributioneffectsontotalionchambercurrentEstimatedError(Iofratedpower)AssumedError(XofratedPower)+5(b)0710L:614-15 TABLE14-4(Continued)DETERMINATIONOFMAXIMUMOVERPOWERTRIPPOINT-POWERRANGENEUTRONFLUXCHANNEL-BASEDONNOMINALSETPOINTCONSIDERINGINHERENTINSTRUMENTERRORSVariableAccuracyofMeasurementofVariableXerrorEffectOnThermalPowerDetermination5error(Estimated)(Assumed)InstrumentationchanneldriftandsetpointreproducibilityEstimatedError(5ofratedpower)AssumedError(Xofratedpower)+2(c)Totalassumederrorinsetpoint(a)+(b)+(c)PercentofRatedPowerNominalSetpoint109Maximumoverpowertrippointassumingallindividualerrorsaresimultaneouslyinthemostadversedirection1180710L:614-16 Figure14-1GinnaCoreLimitsandOverpower-OvertemperatureaTSetpoints6664625654O52o58~~48464442L((oO\'\'\'\Qbf.C'>HIT5A%50rs(h'\'\'\wVOOs:(h0(4((5256IC(.~"PCfpylef5unc,rgSf'af~gvalve>apI5755885655985956886856l86I56286256B8TevgloF')14-17 Figure14-2ReactivityCoefficientsUsedinNon-LocaSafetyAnalysisQQ2L~-10.ge-18020406080100Power,XMostPositivesgttgeyeast500540560T,'F14-18

.Figure14-3ReactivityInsertionScramCurves1.0.8.6.4.20.2.4.6.81.0NormalizedPosition1.21.0Q.8OO7g.6p.4OashpotII.20.2.4.6.81.01.2Norma1izedTime14-19.

14.1.1UncontrolledRCCAWithdrawalfromaSubcriticalConditionARCCAwithdrawalincidentisdefinedasanuncontrolledadditionofreactivitytothereactorcorebywithdrawalofrodclustercontrolassembliesresultinginapowerexcursion.Whilethepr'obabilityofatransientofthistypeisextremelylow,suchatransientcouldbecausedbyamalfunctionofeitherthereactorcontrolorcontrolroddrivesystems.ThiscouldoccurwiththereactoreithersubcriticaloI'tpower.The"atpower"caseisdiscussedinSection14.1.2.Reactivityisaddedataprescribedandcontrolledrateinbringing,thereactorfromashutdownconditiontoalowerpowerlevelduringstartupbyRCCAwithdrawal.Althoughthe'nitialstartupprocedureusesthe"Imethodofborondilution,thenormalstartupiswithRCCAwithdrawal.RCCAmotioncancausemuchfasterchangesinreactivitythancanbemadebychangingboronconcentration.Therodclusterdrivemechanismsarewiredintopreselectedgroups,andthesegroupconfigurationsarenotalteredduringcorelife.Therodst..arethereforephysicallypreventedfromwithdrawinginotherthantheirrespectivegroups.Powersuppliedtotherodgroupsiscontrolledsuchthatnomorethantwogroupscanbewithdrawnatanytime.Theroddrivemechanismisofthemagneticlatchtypeandthecoilactuationissequencedtoprovidevariablespeedrodtravel.Themaximumreactivityinsertionrateisanalyzedinthedetailedplantanalysisassumingthesimultaneouswithdrawalofthecombinationofthetworodgroupswiththemaximumcombinedworthatmaximumspeed.0710L614'.1-1 Theneutronfluxresponsetoacontinuousreactivityinsertionischar-acterizedbyaveryfastrise,terminatedbythereactivityfeedbackeffectofthenegativeDopplercoefficient.Thisself-limitationofthepowerexcursionisofprimaryimportance,sinceitlimitsthepowertoatolerablelevelduringthedelaytimeforprotectiveaction.Ifacon-tinuousrodclustercontrolassemblywithdrawalaccidentoccurs,thetransientisterminatedbythefollowingautomaticfeaturesofthereac-torprotectionsystem:1.Sourcerangeleveltrip-actuatedwheneitheroftwoindepen-dentsourcerangechannelsindicatesafluxlevelaboveapre-selected,manuallyadjustablevalue.Thistripfunctionmaybemanuallybypassedwheneitheroftheintermediaterangefluxchannelsindicateafluxlevelabovethesourcerangecutoffpowerlevel.Itisautomaticallyreinstatedwhenbothinter-mediaterangechannelsindicateafluxlevelbelowthesourcerangecutoffpowerlevel.2.Intermediaterangerodstop-actuatedwheneitheroftwoinde-pendentintermediaterangechannelsindicatesafluxlevelaboveapreselected,manuallyadjustablevalue.ThisrodstopmaybemanuallybypassedwhentwooutofthefourpowerrangechannelsindicateapowerlevelaboveapproximatelylOXpower.Itisautomaticallyreinstatedwhenthreeofthefourpowerrangechannelsarebelowthisvalue.3.Intermediaterangefluxleveltrip-actuatedwheneitheroftwoindependentintermediaterangechannelsindicatesafluxlevelaboveapreselected,manuallyadjustablevalue.Thistripfunc-tionmaybemanuallybypassedwhentwoofthefourpowerrangechannelsarereadingaboveapproximately10Kpowerandisauto-maticallyreinstatedwhenthreeofthefourchannelsindicateapowerlevelbelowthisvalue.0710L:614.1.1"2 4.Powerrangefluxleveltrip(lowsetting)-actuatedwhentwooutofthefourpowerrangechannelsindicateapowerlevelaboveapproximately25~.Thistripfunctionmaybemanuallybypassedwhentwoofthefourpowerrangechannelsindicateapowerlevelaboveapproximately105powerandisautomaticallyreinstatedwhenthreeofthefourchannelsindicateapowerlevelbelowthisvalue.5.Powerrangefluxleveltrip(highsetting)-actuatedwhentwooutofthefourpowerrangechannelsindicateapowerlevelaboveapresetsetpoint.Thistripfunctionisalwaysactive.MethodofAnalsisArodclustercontrolassemblywithdrawalaccidentisanalyzedbythreedigitalcomputercodes.Theanalysisi'sperformedinthreestages:first,anaveragecorenuclearpowertransientcalculation;thenanaveragecoreheattransfercalculation;andfinallytheDNBRcalcula-tion.Theaveragenuclearcalculationisperformedusingaspatialneutronkineticscode,TWINKLE,averagepowergenerationwithtimein-cludingthevarioustotalcorefeedbackeffects,i.e.,Dopplerandmoderatorreactivity.TheFACTRANcodeisthenusedtocalculatethethermalheatfluxtransient,basedonthenuclearpowertransientcalculatedbyTWINKLE.FACTRANalsocalculatesthefuelandcladtemperatures.TheaverageheatfluxisnextusedinTHING,References18and19,fortransientDNBRcalculation.ThisaccidentisanalyzedusingtheImprovedThermalDesignProcedureasdescribedinReference6.PlantcharacteristicsandinitialconditionsarediscussedinSection4.0710L:614.1.1-3 Inordertogiveconservativeresultsforastartupaccident,thefol-lowingadditionalassumptionsaremadeconcerningtheinitialreactorconditions:1.Sincethemagnitudeofthenuclearpower'peakreachedduringthe"initialpartofthetransient,foranygivenrateofreactivityinsertion,isstrongly.dependentontheDopplercoefficient,conservativelylowvalues(lowabsolutemagnitude)asafunctionoftemperatureareused.2.,ThecontributionofthemoderatorreactivitycoefficientisnegligibleduringtheinitialpartofthetransientbecausetheheattransfertimebetweenthefuelandthemoderatorismuchlongerthanthenuclearfluxresponsetimeHowever,aftertheinitialnuclear'fluxpeak,the'ucceedingrateof'owerincrease'saffectedbythemoderatorreactivitycoefficient.Accord-ingly,aconservativevalueof+5.0pcm/'Fatzeropower.is,used,becausethisyields.themaximumpeakheatflux.I3.Thereactorisassumedtobejustcriticalathotzeropower(no-loadaveragetemperature)'.Thisassumptionismorecon-servativ'ethanthatofalower'nitialsystemtemperature.The.Ihigherinitial'ystemtemperatureyieldsalargerfuelwaterheattransfercoefficient,largerspecificheats,andalessnegative(smallerabsolutemagnitude)Oopplercoefficient-allofwhichtendtoreducetheOopplerfeedbackeffect,therebyincreasingtheneutronfluxpeak.Theinitialeffectivemulti-plicationfactorisassumedtobe1.0,sincethisresultsinmaximumneutronfluxpeakingand,thus,themostseverenuclearpowertransient.0710L:614.1.1"4 4.Reactortripis,assumedtobeinitiatedbythepowerrangeflux.leveltrip(lowsetting).Themostadversecombinationofin-strumentandsetpointerrors,aswellasdelaysfortripsignalactuationandrodclustercontrolassemblyrelease,istakenintoaccount.A10percentincreaseisassumedforthepowerrangefluxtripsetpoint,raisingitfromthenominalvalueof25percentto35percent.Previousresults,however,showthatrise,intheneutronfluxissorapidthattheeffectoferrorsin.thetripsetpoint,ontheactualtimeatwhichtherodsarereleasedisnegligible.Inaddition,thereactortripinsertioncharacteristicisbasedontheassumptionthatthehighestworthrodclustercontrolassemblyisstuckinitsfullywithdrawnposition.5.Themaximumpositivereactivityinsertionrateassumed(97.5pcm/sec)isgreaterthanthatforthesimultaneouswithdrawalofthecombinationofthetwocontrolbankshavingthegreatestcombinedworthatmaximumspeed(45inches/minute).6.Themostlimitingaxialandradialpowershapes,associatedwithhavingthetwohighestcombinedworthsequentialbanksintheirhighestworthposition,areassumedforDNBanalysis.7.Theinitialpowerlevelwasassumedtobebelowthepowerlevel"9expectedforanyshutdowncondition(10ofnominalpower).Thecombinationofhighestreactivityinsertionrateandlowestinitialpowerproducesthehighestpeakheatflux.8;Onereactorcoolantpumpisassumedtobeinoperation.ThislowestinitialflowminimizestheresultingDNBR.0710L:614.1.1-5 ResultsThecalculatedsequenceofeventsisshowninTable14.1.1-1.Figures14.1.1-1and14.1.1-2showthetransientbehaviorfortheindicatedreactivityinsertionratewiththeaccidentterminatedbyreactortripat35percentnominalpower.Thisinsertionrateisgreaterthanthatforthetwohighestworthcontrolbanks,bothassumedtobeintheirhighestincremental'orthregion.Figure14.1.1-1showstheneutronfluxtransient.Theenergyreleaseandthefueltemperatureincreasesarerelativelysmall..Thethermalfluxresponse,ofinterestfordeparturefromnucleateboilingconsiderations,isshowninFigure14.1.1-1.Thebene-ficialeffectontheinherentthermallaginthefuelisevidencedbya(peakheatfluxlessthanthefull-powernominalvalue.Thereisalarge,'~margin-to-departurefromnucleateboilingduringthetransient,since<therodsurfaceheatfluxremainsbelowthedesignvalue,and.thereisahighdegreeofsubcoolingatalltimesinthecore.Figure14.1.1"2showstheresponseofthehotspotaveragefuelandcladding'empera-ture.Theaveragefueltemperatureincreasestoavaluelowerthanthenominalful1-powervalue.TheminimumDNBRatalltimesremainsabovethelimitvalue.Thecal-culatedsequenceofeventsforthisaccidentisshowninTable14.1.1-1.Withthereactortripped,theplantreturnstoa'stablecondition.Theplantmaysubsequentlybecooleddownfurtherbyfollowingnormalplantshutdownprocedures.0710L:614.1.1"6 ConclusionIfarodclustercontrolassemblywithdrawalaccidentfromthesubcrit-icalconditionoccurs,thecoreandthereactorcoolantsystemarenotadverselyaffected,sincethedeparturefromnucleateboilingratioremainsabovethelimitvalue.I0710L:614.1.1-7 TABLE14.1.1-1TIMESEQUENCEOFEVENTSFORUNCONTROLLEDRCCAWITHDRAWALFROMASUBCRITICALCONDITIONEventTimeofEachEventSecondsInitiationofuncontrolledrodwithdrawal,97.5pcm/secondreactivityinsertionrate,from-910ofnominalpowerPowerrangehighneutronfluxlowsetpointreached8.09Peaknuclearpoweroccurs8.21Rodsbegintofallintocore8.59PeakheatfluxoccursMinimumDNBRoccurs10.25Peakcladtemperatureoccurs10.53Peakaveragefueltemperatureoccurs10.630710L:614.1.1-8 Figure14.1.1-'1GinnaUncontrolledRCCABankWithdrawalfromSubcritical,1.0O.1.01t.0000.80000.60000I+.iooOO.@XYLO0.0C5CDCDCIIDCDCICICICDCDCICICCJCDnICJCDCImTlHE(SEC)

Figure14.1.1-2GinnaUncontrolledRCCABankWithdrawalfromSubcriticali100.0INN.0a1750.01500.0M50.01000.0027.00UJaO.00oC00.00SCICtTilelSKC)CICIAJClCICIm14.I.1-10 14.1.2UncontrolledRCCAWithdrawalatPowerAnuncontrolledRCCAwithdrawalatpowerresultsinanincreaseincoreheatflux.Sincetheheatextractionfromthesteamgeneratorremainsconstant,thereisanetincreaseinreactorcoolanttemperature.Un"lessterminatedbymanualorautomaticaction,thispowermismatchandresultantcoolanttemperaturerisewouldeventuallyresultinDNB.Therefore,topreventthepossibilityofdamagetothecladding,theReactorProtectionSystemisdesignedtoterminateanysuchtransientwithanadequatemargintoDNB.TheautomaticfeaturesoftheReactorProtectionSystemwhichpreventcoredamageinarodwithdrawalaccidentatpowerincludethefollowing:1.Nuclearpowerrangeinstrumentationactuatesareactortripiftwooutofthefourchannelsexceedanoverpowersetpoint.Lv2.ReactortripisactuatedifanytwooutoffourhTchannelsexceedanovertemperaturehTsetpoint.Thissetpointisauto-maticallyvariedwithaxialpowerimbalance,coolanttemperatureandpressuretoprotectagainstDNB.3.ReactortripisactuatedifanytwooutoffourhTchannelsexceedanoverpowerhTsetpoint.Thissetpointisautomati-callyvariedwithaxialpowerimbalanceandcoolanttemperaturetoensurethattheallowableheatgenerationrate(kw/ft)isnotexceeded.4.Ahighpressurereactortrip,actuatedfromanytwooutofthreepressurechannels,issetatafixedpoint.Thissetpressurewillbelessthanthesetpressureforthepressurizersafetyvalves.0710L614.1.2"1 5.Ahighpressurizerwaterlevelreactortrip,actuatedfromanytwooutofthreelevelchannels,isactuatedatafixedset-point.ThisaffordsadditionalprotectionforRCCAwithdrawalaccidents.ThemannerinwhichthecombinationofoverpowerandovertemperaturehTtripsprovidesprotectionoverthefullrangeofreactorcoolantsystemconditionsisillustratedinFigure14-1.Figure14-1presentsallowablereactorloopaveragetemperatureandhTforthedesignpowerdistributionandflowasafunctionofprimarycoolantpressure.TheboundariesofoperationdefinedbytheoverpowerhTtripandtheover-temperaturehTtriparerepresentedas"protectionlines"onthisdiagram.Theseprotectionlinesaredrawntoincludealladverseins-trumentationandsetpointerrors,sothatundernominalconditionstripwouldoccurwellwithintheareaboundedbytheselines.Amaximumsteady-stateoperatingconditionforthereactorisalsoshownontheFigure.Theutilityofthediagramjustdescribedisinthefact'hattheopera-tinglimitimposedbyanygivenDNBratiocanberepresentedasalineonthiscoordinatesystem.TheDNBlinesrepresentthelocusofcondi-tionsforwhichtheDNBRequalsthelimitvalue.AllpointsbelowandtotheleftofthislinehaveaDNBratiogreaterthanthisvalue.ThediagramshowsthatDNBispreventedforallcasesiftheareaenclosedwithinthemaximumprotectionlinesisnottraversedbytheapplicableDNBratiolineatanypoint.Theregionofpermissibleoperation(power,pressureandtemperature)iscompletelyboundedbythecombinationofreactortrips:nuclearover-power(fixedsetpoint);.highpressure(fixedsetpoint);lowpressure0710L:6'4.1.2-2

(fixedsetpoint);overpowerandovertemperaturehT(variableset-points).ThesetripsaredesignedtopreventoverpowerandaDNBratiooflessthanthelimitvalue.MethodofAnalsisqCjVUncontrolledrodclustercontrolassemblybankwithdrawalisanalyzedbytheLOFTRANcode.Thiscodesimulatestheneutronkinetics,reactorcoolantsystem,pressurizer,pressurizerreliefandsafetyvalves,pres-surizerspray,steamgenerator,andsteamgeneratorsafetyvalves.Thecodecomputespertinentplant'variables,includingtemperatures,pres-sures,andpowerlevel.Thecorelimits,asillustratedinFigure14-1,areusedasinputtoLOFTRANtodeterminetheminimumdeparturefromnucleateboilingratioduringthetransient.ThisaccidentisanalyzedwiththeImprovedThermalDesignProcedureasdescribedinReference6.PlantcharacteristicsandinitialconditionsarediscussedinSection14.Inordertoobtainconservativevaluesofdeparturefromnucleateboil-ingratio,thefollowingassumptionsaremade:1.InitialConditions-Initialreactorpower,reactorcoolantaveragetemperatures,andreactorcoolantpressureareassumedtobeattheirnominalvalues.UncertaintiesininitialconditionsareincludedinthelimitDNBRasdescribedinReference6.2.ReactivityCoefficients-Twocasesareanalyzed.a.MinimumReactivityFeedback-Apositive(Spcm/'F)modera"torcoefficientofreactivityisassumed,correspondingtothebeginning-of-core-life.AvariableDopplerpowercoef-ficientwithcorepowerisusedintheanalysis.Aconser-vativelysmall(inabsolutemagnitude)valueisassumed.0710L:614.1.2-3

(/b.HaximumReactivityFeedback-Aconservativelylargeposi-tivemoderatordensitycoefficientandalarge(inabsolutemagnitude)negativeDopplerpowercoefficientareassumed.3.Therodclustercontrolassemblytripinsertioncharacteristicisbasedontheassumptionthatthehighestworthassemblyis,stuckinitsfullywithdrawnposition.4.Thereactortriponhighneutronfluxisassumedtobeactuatedataconservativevalueof1185ofnominalfullpower.Theovertemperature4Ttripincludesalladverseinstrumentationandsetpointerrors;thedelaysfortripactuationareassumedtobethemaximumvalues.Nocreditwastakenfortheotherexpectedtripfunctions.5.Themaximumpositivereactivityinsertionrateisgreaterthanthatforthesimultaneouswithdrawalofthecombinationofthetwocontrolbankshavingthemaximumcombinedworthatmaximumspeed.Theeffectofrodclustercontrolassemblymovementontheaxialcorepowerdistributionisaccountedforbycausingadecreaseinover-temperatureandoverpowerbTtripsetpointsproportionaltoadecreaseinmargintoDNB.ResultsFigures14.1.2-1through14.1.2-3showtheplantresponse(includingneutronflux,pressure,averagecoolanttemperature,anddeparturefromnucleateboilingratio)toarapidrodclustercontrolassemblywithdrawalincidentstartingfromfullpower.Reactortriponhighneutronfluxoccursshortlyafterthestartoftheaccident.Sincethisisrapidwithrespecttothethermaltimeconstantsoftheplant,smallchangesinTandpressureresult,andalargemargintoDNBisavgmaintained.0710L:614.1.2-4 TheplantresponseforaslowcontrolrodassemblywithdrawalfromfullpowerisshowninFigures14.1.2-4through14.1.2-6.ReactortriponovertemperaturehToccursafteralongerperiod,andtheriseintemperatureandpressureisconsequentlylargerthanforrapidrodclustercontrolassemblywithdrawal.Again,theminimumDNBRisgreaterthanthelimitvalue.Figure14.1.2-7showstheminimumdeparturefromnucleateboilingratioasafunctionofreactivityinsertionratefrominitialfull-poweroper-ationfortheminimumandmaximumreactivityfeedbackcases.Itcanbeseenthattworeactortripchannelsprovideprotectionoverthewholerangeofreactivityinsertionrates.Thesearethehighneutronfluxa'ndovertemperaturehTtripchannels.TheminimumDNBRisneverlessthanthelimitvalue.Figures'4.1.2-8and14.1.2-9showtheminimumdeparturefromnucleateboilingratioasafunctionofreactivityinsertionrateforrodclustercontrolassembly'withdrawalincidentsstartingat60/and10'opowerrespectively.Theresultsaresimilartothe100Kpowercase,exceptthatastheinitialpowerisdecreased,therangeoverwhichtheover-temperaturehTtripiseffectiveisincreased.InneithercasedoesthedeparturefromnucleateboilingratiofallbelowtheDNBRlimitvalue.Inthereferencedfigures,theshapeofthecurvesofminimumdeparturefromnucleateboilingratioversusreactivityinsertionrateisduebothtoreactorcoreandcoolantsystemtransientresponseandtoprotectionsystemactionininitiatingareactortrip.0710L:614.1.2-5 ReferringtoFigure14.1.2-9,forexample,itisnotedthat:1~For.highreactivityinsertionrates(i.e.,between-3"5-lxlOhk/secondand-3.0x10hk/second),reactortripisinitiatedbythehighneutronfluxtripfortheminimumreactivityfeedbackcases.Then'eutronfluxlevelinthecorerisesrapidlyfortheseinsertionrates,whilecoreheatfluxandcoolantsystemtemperaturelagbehindduetothethermalcapacityofthefuelandcoolantsystemfluid.-Thus,thereac-,'oristrippedpriortosignificantincreaseinheatfluxorwatertemperaturewithresultanthighminimumdeparturefromnucleateboilingratiosduringthetransient.Withinthisrange,asthereactivityinsertionratedecreases,coreheatfluxandcoolanttemperaturescanremainmorenearlyinequili-briumwiththeneutronflux;minimumDNBRduringthetransientthusdecreaseswithdecreasinginsertionrate.2.Withfurtherdecreaseinreactivityinsertionrate,theover-temperaturehTandhighneutronfluxtripsbecomeequallyeffectiveinterminatingthetransient(e.g.,at"5-3.0x10hk/secondreactivityinsertionrate).TheovertemperaturehTreactortripcircuitinitiatesareac-tortripwhenmeasuredcoolantloophTexceedsasetpointbasedonmeasuredreactorcoolantsystemaveragetemperatureandpressure.Itisimportantinthis'contexttonote,however,thattheaveragetemperaturecontributiontothecircuitislead-lagcompensatedinordertodecreasetheeffectofthethermalcapacityofthereactorcoolantsysteminresponseto'owerincreases.-5Forreactivityinsertionratesbetween-3.0x10hk/second-6and-6.0xlOhk/second,theeffecti'venessoftheover-temperaturehTtripincreases(intermsofincreasedminimumdeparturefromnucleateboilingratio)due.tothefactthat,0710L:614.1.2-6 withlowerinsertionrates,thepowerincreaserateisslower,therateofriseofaveragecoolanttemperatureisslower,andthelead-lag.compensationprovidedcanincreasinglyaccountforthecoolantsystemthermalcapacitylag.3.Formaximumreactivityfeedbackcasesreactivityinsertionrates-4lessthan-5.0x10hk/second,theriseinreactorco'olanttemperatureissufficientlyhighsothatthesteamgeneratorsafetyvalvesetpointisreachedpriortotrip.Openingthesevalves,whichactasanadditionalheatloadonthereactorcoolantsystem,sharplydecreasestherateofriseofreactorcoolantsystemaveragetemperature.Thisdecreaseinrateofriseoftheaveragecoolantsystemtemperatureduringthetran-sientisaccentuatedbythelead-lagcompensation,causingtheovertemperaturehTtripsetpointtobereachedlaterwithresultinglowerminimumdeparturefromnucleateboilingratios.Figures14.1.2-7,14.1.2-8,and14.1.2-9i.llustrateminimumdeparturefromnucleateboilingratiocalculatedforminimumandmaximumreac-tivityfeedback.ThecalculatedsequenceofeventsforthisaccidentisshowninTable14.1.2-1.ConclusionsIntheunlikelyeventofacontrolrodwithdrawalincident,fromfull-poweroperationorlowerpowerlevels,thecoreandreactorcoolantsystemarenotadverselyaffectedsincetheminimumvalueofDNBratioreachedisinexcessoftheDNBlimitvalueforallrodreactivityrates.ProtectionisprovidedbynuclearfluxoverpowerandovertemperaturehT.Additionalprotectionwouldbeprovidedbythehighpressurizerlevel,overpowerhT,andthehighpressurereactor.trip.Theprecedingsectionshavedescribedtheeffectivenessoftheseprotectionchannels.0710L:614.1.2-7 TABLE14.1.2-1TIMESEQUENCEOFEVENTSFORUNCONTROLLEDRCCAWITHDRAWALATPOWER,EventTimeofEachEventSecondsCaseA:Initiationofuncontrolledrodclustercontrolassemblywithdrawalatfullpowerandmaximumreactivityinsertionrate(90pcm/sec)Powerrangehighneutronfluxhightrippointreached3.21Rodsbegintofallintocore3.71Minimumdeparturefromnucleateboilingratiooccurs4.00CaseB:Initiationofuncontrolledrodclustercontrolassemblywithdrawalatfullpowerandatasmallreactivityinsertionrate(7pcm/sec)OvertemperaturehTreactortripsignalinitiated264.7Rodsbegintofallintocore266.7Minimumdeparturefromnucl'cateboilingratiooccurs267.00882L:614.1~2-8 Figure14.1.2-1GinnaUncontrolledRCCABankMithdrawalatPowerfiAXIfiUMFEEDBACK100%Power,90pcm/secl.20001.0000x0X.soooo0Pg.SDOOO.ioooo4.200000.0l.2000l.0000.soooo~~".60000K.loooo.20000d00b0000000O00OO0O000000000~Alsrn0g000OTlHE(SEC)14.1.2-9 Figure14.1.2-2GinnaUncontrolledRCCAHankWithdrawalatPower100'4Power,90pcm/seciiAXIMUMFEEDBACK2S00.02100.02300.0I82200.0~~~2loo.02000..0$1800.0ILlSOO.0l700.0looo.00900.00LJ800.004J700.00600.00S00.00ioo.000088000080000000000000000'00~Alfoal+V1lD>00TIRElSKC)14.1.2-10 Figure14.1.2-3GinnaUncontro11edRCCABankWithdrawa1atPowerHAXItlUt1FEEDBACK100Power,90pcm/sec620.00610.00600.00590.00560.00570.00560.00550.00510.005.00001.5000'.0000/3.5000I3.00002.50002.00001.5000l.20000O80000380000OO0O0O0tve'nco000O01TlHEtSEC)14.1.2-11 Figure14.1.2-4GinnaUncontrolledRCCABankWithdrawalatPowert.2000100%Power,7pcm/secllAXItlUf3FEEDBACK.xl.0000XCD.80000IPK.60000CD0CC.i0000~200000.0t.2000l.0000XF80000.60000.l0000I.200000.0~DCDCDCDCCJCDCDCCJCDCDCDTAHEtSEC)14.1.2-12

Figure14.1.2-5GinnaUncontr01ledRCCAHankWithdrawa1atPower100%Power,7pcm/sec.f1AXItlUflFEEOBACK2500.0Zioo.02300.0Xc2200.021oo.o2000.0]800.041800.01?00.01000.00500.DD800.00X100.00ClSDD.00500.00ioo.00ClCICl3VIClClClClClT1HEt5KQClClAJClClV7Clm14.1.2-13 Figure14.1.2-6GinnaUncontrolledRCCABankWithdrawalatPower620.00100~Power,7pcm(secMAXIMUMFEEOBACK610.00600.00SSO.OO5sso.oo570.00560.00550.00Sio.001.00003.50003.0000O2.50OO2.0000l.50001.2OO0OCIlOCIClClOClClTlHE<SEC)OOOOAJOOOAlClClm14.1.2-]4 Figure14.1.2-7GinnaUncontrolledBankMithdrawalfrom100"PowerMaximumFeedback---MinimumFeedback2.12.01.9rrHighFlux1.8OTzT1.7~I10100ReactivityInsertionRate,pcm/sec

Figure14.1.2-8GinnaUncontrolledBankWithdrawalfrom60~PowerMaximumFeedback---MinimumFeedbackIIIII2.52.42a32.22.12.0OTLT///////////////HighFluxOTaT/t/)q310100ReactivityInsertionRate,pcm/sec14.1.2-16 Figure14.1.2-9GinnaUncontrolledBank'Withdrawalfrom10Power,HaximumFeedback---MinimumFeedbackIII>>>>II~2>>52.42.32.2////If/0,///'////OTBT/HighFlUX///'L///2.12.010100ReactivityInsertionRate,pcm/sec14.1.2-17 0

14.1.4RodClusterControlAssembly(RCCA)DropDroppingofafull-lengthRCCAoccurswhenthedrivemechanismis<deen-ergized.Thiswouldcauseapowerreductionandanincreaseinthehotchannelfactor.Ifnoprotectiveactionoccurred,theReactorControlSystemwouldrestorethepowertothelevelwhichexistedbeforetheincident.ThiswouldleadtoareducedsafetymarginorpossiblyDNB,dependinguponthemagnitudeoftheresultanthotchannelfactor.IfanRCCAdropsintothecoreduringpoweroperation,itwouldbedetectedeitherbyarodbottomsignal,byanout-of-corechamber,orbyboth.TherodbottomsignaldeviceprovidesanindicationsignalforeachRCCA.TheotherindependentindicationofadroppedRCCAisob-tainedbyusingtheout-of-corepowerrangechannelsignals.Thisroddropdetectioncircuitisactuateduponsensingarapiddecreaseinlocalfluxandisdesigned'suchthatnormalloadvariationsdonotcauseittobeactuated.Aroddropsignalfromanyrodpositionindicationchannel,orfromoneormoreofthefourpowerrangechannels,initiatesthefollowingpro-tectiveaction:reductionoftheturbineloadbyapresetadjustableamountandblockingoffurtherautomaticrodwithdrawal.Theturbinerunbackisachievedbyactingupontheturbineloadlimitandontheturbineloadreference.Therodwithdrawalblockisredundantlyachieved.ThetransientfollowingadroppedRCCAaccidentisdeterminedbyade-taileddigitalsimulationoftheplant.ThedroppedrodcausesastepdecreaseinreactivityandthecorepowergenerationisdeterminedusingtheLOFTRANcode.Theoverallresponseiscalculatedbysimulatingtheturbineloadrunbackandpreventingrodwithdrawal.Theanalysisispresentedforthecaseinwhichtheloadcutbackveryclosely'matchesthepowerdecreasefromthenegativereactivityforadroppedrod0882L:614.1.4-1 (800pcm)andalsoforthecaseinwhichtheloadcutbackisgreaterthanthatrequiredtomatchtheworthofthedroppedrod(100pcm).Inbothcasestheloadisassumedtobecutbackfrom100to84Koffullloadataconservativelyslowrateofapproximately1%persecond.ThemostnegativevaluesofmoderatorandDopplertemperaturecoeffi-cientsofreactivityareusedinthis'analysisresultinginthehighestheatfluxduringthetransient.Theseareamoderatordensitycoefficientofreactivityof.43hp/gm/ccandaDopplertemperature-5coefficientofreactivityof-2.9x10hk/F.ThisaccidentisanalyzedwiththeImprovedThermalDesignProcedureasdescribedinWCAP-8567(Reference6).PlantcharacteristicsandinitialconditionsarediscussedinSection14.ResultsFigures14.1.4-1through14.1.4-3illustratethetransientresponsefol-lowingadroppedrodofworth100pcm.Thecoolanttemperaturedecreasesinitiallyduetothefactthatmoreenergyistakenoutfromthesecondarythanproducedintheprimary,thenincreasesundertheinfluenceofthenegativereactivityeffectofthemoderatorandDopplertemperaturecoefficients.Thepeakheatfluxfollowingtheinitialresponsetothedroppedrodis97Kofnominal.Figures14.1.4-4and14.1.4-6illustratethetransientresponsefollow-ingadroppedrodofworth800pcm.Againthereactorcoolantaveragetemperaturedecreasesinitially,andthenincreasesbecauseofthenegativereactivityfeedback.Forthiscase,thepeakheatfluxfollowingtheinitialresponsetothedroppedrodis84%ofnominal.Atthesametimethecoreaveragetemperaturedrops11.8'Fandthepres-suredrops130psia.0882L:614.1.4-2 Ananalysishasbeenmadeforthedroppedrodsattheconditionsofpeakheatfluxfollowingtheinitialresponsetothedroppedrod.Thisanalysisincorporatestheincreaseinradialhotchannelfactorcausedbythedroppedrods.ItwasfoundthattheDNBRdoesnotfallbelowthelimitvalue.AnanalysishasbeenalsomadeoftheamountofastaticallymisalignedRCCAforthemaximumfullpoweroperatingconditions(100%power;corewaterinlettemperatureof543.7'F;primarypressureof2250psia).Theeffectofthestaticmisalignedrodincidentwasrepresentedbyanincreaseintheradialheatfluxhotchannelfactor.Itwasfoundthat~theincreasedFHcouldbeaccommodatedwithoutthe'NBRfallingbelowthelimitvalue.ConclusionsProtectionforadroppedRCCAisprovidedbyautomaticturbinerunbackandblockingofautomaticrodwithdrawal.Astheanalysesshow,theprotectionsystem,inconjunctionwiththeturbinerunback,protectsthecorefromDNB.Additionally,forastaticmisalignmentatmaximumfull-powerconditions,DNBwillnotoccur.0882L:614.1.4-3

'igure14.1.4-1,GinnaDroppedRod-100pcm~~1.20001.0000C).80000ICC.6oooo.40000u.20000?0.01.20001.0000XC),80000?.').60000.loooo.200000.0ClEDC7C7C)C)C)O0OIO0OC)C>C>TlkE(SEC114.1.4-4 Figure14.1.4-2GjnnaDroppedRod100pcm2500.02400.02300.0cX2200.0CCleCCCCl4/1CC02300.02000.0>8OO.Ol800.01700.0620.006'!0.00sao.oo590.,00580.00510.00Sppp550.005i0.00oCDPPPPCVPPPPP~PCDCDCDPPCDmlACDCDCDCDCDCDCDTlÃE<SEC)14.1.4-5 Figure14.1.4-3GinnaDroppedRod-100pcml2000XCI1.0000F80000~60000.10000IC~200000.0C7CICICICICICICICICICImCICICICICICICICIIVICICICIIDCICICII1M'HAEC)14.1.4-6 Figure14.1.4-4GinnaDroppedRod-800pen1.2000z1.0000XCIZCDClILJCL.80000.60000cD.F0000.200000.01.20001.0000.80000.60000.10000lx~200000.0CDCDCICDCIClCICIJClCICIClmClClCIClv\ClClCDClClClClTIME(SEC)14.1.4-7 Figure14.1.4-5GinnaDroppedRod-800pcm2500.02400.02300.0Xc2200.02l00.02000.0gl900.0l800.0l700.0620.006lo.00600.00540.00580.00570.00560.00550.00540.00CDClClC)C)C'0y>C14.1.4-8 Figure14.1.4-'6GinnaDroppedRod-.800pcm1.2000l.0000.SOOOOCIICC.60000.F0000E.200000.0CICICICIC)CICIC7CImCICICICICICICITIMEtCIiC>14.1.4-9 14.1.5ChemicalandVolumeControlSystemMalfunctionReactivitycanbeaddedtothecorewiththeChemicalandVolumeControlSysembyfeedingreactormakeupwaterin.otheReactorCoolantSystemviathereac.ormakeupcontrolsystem.Thenormaldilutionprocedurescallforalimitontherateandmagnitudeforanyindividualdilution",understrictadministrativecontrols.Borondilutionisamanualopera-tion.Aboricacidblendsystemisprovidedtopermittheoperatortomatchtheconcentrationofreactorcoolantmakeupwatertohatexistinginthecoolantatthetime.TheChemicalandVolumeControlSys.emisdesignedtolimit,evenundervariouspostulatedailuremodes,the.potentialrateofdilutiontoavaluewhich,afterindicationthroughalarmsandins.rumentation,providestheoperatorsuficienttimetocorrectthesituatjoninasafeandorderlymanner.ThereisonlyasinglecommonsourceofreactormakeupwatertotheReactorCoolantSystemfromthereactormakeupwaterstoragetank,andinadvertentdilutioncanbereadilyterminatedbyisolatingthissinglesource.TheoperationofthereactormakeupwaterpumpswhichtakesuctionfromhistankprovidestheonlysupplyofmakeupwatertotheReac.orCoolantSystem.InorderformakeupwatertobeaddedtotheReactorCoolantSystemthechargingpumpsmustberunninginadditiontothereactormakeupwaterpumps.TherateofadditionofunboratedwatermakeuptotheReac.orCoolantSys.emislimitedtothecapacityofthemakeupwaterpumps.Thislimitingadditionrateis120gpmfortworeactormakeupwaterpumps.iorotallyunboratedwatertobedeliveredatthisratetotheReactorCoolantSystematpressure,twochargingpumpsmustbeoperatedatfullspeed.Normally,twochargingpumpsareoperatingathalfspeed,whilethethirdpumpisidle.Theboricacidfromtheboricacidtankisblendedwiththereactormakeupwaterintheblenderandthecompositionisdeterminedbythepresentflowratesofboricacidandreac.ormakeupwaterontheReactor0882L:614.1.5-1

MakeupControl.Twoseparateoperationsarerequired.First,theoper-atormusswitchfromtheautomaticmakeupmodetothedilutemode.Second,thesartbuttonmustbedepressed.Omittingei.herstepwouldpreventdilution.Thismakesthepossibilityofinadvertentdilutionverysmall.InformationonthestatusofthereacorcoolantmakeJpiscontinuouslyavailabletotheoperator.LightsareprovidedonthecontrolboardtoindicatetheoperatingconditionofpumpsintheChemicalandVolumeControlSystem.Alarmsareactuatedtowarntheopera.orifboricacidordemineralizedwaterflowratesdeviatefrompresetvaluesasaresultofsystemmalfunc.ion.Tocoverallphasesofplantoperation,borondilutionduringrefueling,startup,andpoweroperationareconsideredinthisanalysis.IMethodofAnalsisandResultsDilutionDurinRefuelinDuringrefueling'thefollowiagconditionsexist:a)Oneresidualheatremovalpumpisrunningtoensurecontinuousmix-inginthereactorvessel,b)Thevalvein.hesealwaterheadertothereactorcoolantpumpsisclosed,c)Thevalvesonthesuc.ionsideofthechargingpumpsareadjustedforadditionofconcentratedboricacidsolution.d)Theboronconcentrationoftherefuelingwaterisaminimumof2000ppm,correspondingtoashutdownof""percenthkwithallcontrolrodsin;periodicsamplingensuresthatthisconcentrationismain-tained,and0882L:614.1.5-2

~'1 e)NeutronsourcesareinsalledinthecoreandBFdetecorscon-3nec.edtoinstrumentationgivingaudiblecountratesoprovidedirectmonitoringofthecore.AminimumwatervolumeintheReactorCoolantSystemof2724ftis3considered.Thiscorrespondstothevolumenecessarytofillthereac-torvesseltothemidplaneofthenozzlestoensuremixingviathepesidualheatremovalloop.Themaximumdilutionflowof120gpmanduniformmixingarealsoconsidered.Administrativeprocedureslimithechargingf1owtoonepumpavailable(twopumpslockedout).Themaximumdilutionflowassumesthesinglefailure,suchthattwopumpsaredeliveringmax.'mumflow.Theoperatorhaspromptanddefiniteindicationofanyborondiluionfromtheaudiblecountrateinsrumentation..Highcountrateisalarmedinthereactorcontainmentandthemaincontrolroom.Thecountrateincreaseisproportionaltotheinversemultiplicationfac.or.At1420ppm,forexample,atypicalcoreis4percentshutdownandthecountrateisincreasedbya'factorof3.3overthecountrateat2000ppm.Theboronconcentrationmustbereducedfrom.2000opmtoapproximatelyj500ppmbeforethereacorwillgocritical.Thiswouldtakeatleast'8.8minutes.This'isampletimefortheoperatortorecognizetheaudiblehighcountratesignalandisolatethereac.ormakeupwatersourcebyclosingvalvesandstopping.hereactormakeupwaterpumps.DilutionDurinStar.uoPriortorefueling,theReactorCoolantSystemisfilledwithboratedwaterfromtherefuelingwaterstoragetank.CoremonitoringisbyexternalBF3detectors.Mixingofreactorcoolantisaccomplishedbyoperationofthereactorcoolantpumps.Again,themaximumdilutionflow(120gpm)isconsidered.Thevolumeofreac.orcoolantis0882L:614.1.5"3 01'1 approximately4255ftwhichishevolumeofheReac.orCoolant--.3Systemexcludingthepressurizer.Thisvolumeaccountsfor10.percentsteamgeneratortubeplugging.Highsourcelevelandallreac.ortripalarmsareeffec.ive.Theminimumtimerequiredtoreducethereactorcoolantboronconcentrationto1500ppm,wheretherectorcouldgocriticalwithal"1rodsattheinsertion.limits,isabout.64.1minutes.Onceagain,thisrshouldbemorethanadequatetimeforoperatoractiontothe)'ighcountratesignal,andterminationofdilutionflow.Inanycase,ifcontinueddilutionoccurs,thereactivi.yinsertionra:eandconsequencesthereofareconsiderablylessseverethanthoseassociatedwiththeuncontrolledrodwithdrawalanalyzedinSection14.1.1,UncontrolledRCCAWithdrawalfromaSubcriticalCondition.DilutionatPowerFordilutionatpower,itisnecessarythatthetime.oloseshutdownmarginbesufficienttoallowidentificationoftheproblemandterminationofthedilution.Asinthedilutionduringstar.upcase,theRCSvolumereduc.ionduetosteamgeneratortubepluggingisconsidered.Theeffec.ivereaciviyadditionrateisafunctionof'thereac.orcoolanttemperatureandboronconcentration.Thereactivityinsertionratecalculatedisbasedonaconse.vativelyhighvaluefortheexpectedboronconcentrationatpower(1500ppm)aswellasaconservativelyhighchargingflowratecapacity(127gpm).Thereactori.sassumedtohaveallrods:outineitherautomaticormanualcontrol.Withthereac.orin,manualcontrolandnoopera.oractionto.erminateIthetransient,thepowerandtemperaturerisewillcausethereactortoreachthereactorprotection(i.e.,OThT,highnuclearflux)trip~isetpoint,resultinginareactortrip.Afterreac.ortripthereisatleast53.5minutesforoperatoractionpriortoreturnto0882L:614.1.5-4 t~.~0 criticality.Theborondilutiontransientinthiscaseisesseniallytheequivalenttoanuncontrolledrodwithdrawal'atpower.Themhximumreac.ivityinsertionrateforaborondilutiontransientisconservativelyestimatedtobe,1.6pcm/secandiswi.hintherangeofinsertionratesanalyzedforuncontrolledrodwithdrawalatpower.Prior'toreachingthereactorprotectiontrip,theopera'orwillhavereceivedanalarmonOvertemperaturehTandturbinerunback.>>Withthereactorinautomaticcontrol,aborondilutionwillresultina'owerandtemperatureincreasesuchthattherodcontrollerwillat.empttocomoensatebyslowinsertionofthecontrolrods.Tnisac.ionby.heI,controllerwillresultinrodinsertionlimitandaxialfluxalarms.-Tneminimumtimetolosetheshutdownmarginatbeginningoflifewouldbegreaterthan54.4minutes.'hetimewouldbesignificantlylongeratendoflifeduetothelowinitialboronconcentration.1ConclusionsBecauseoftheproceduresinvolvedinthedilutionprocess,anerroneousdilutionisconsideredincredible.Nevertheless,ifanunintentionaldilutionofboroninthereactorcoolantdoesoccur,numerousalarmsandindicationsareavailabletoaler.theoperatortothecondition."ThemaximumreactivityadditionduetothedilutionisslowenoughtoaIllowtheoperatortodeterminethecauseoftheaddiionandtakecorrec.iveactionbeforeexcessiveshutdownmarginislost.0882L:614.1.S"5 14.1.6LossofReactorCoolantFlowFlowCoas.downAcciden.sAloss-of-coolantflowincidentcanresultfromamechanicalor'lectricalfailureinoneormorereac.orcoolantpumps,orfromafaulinthepowersupplytothesepumps.If,thereactor'isatpoweratthetimeoftheincident,theimmediateeffectofloss"of-coolantflowisarapidincreaseincoolanttemperature.Thisincreasecouldresulindepar.urefromnucleateboiling(DNB)withsubsequentfueldamageifthereac:orisnot.rippedpromptly.Thefollowingtripcircuitsprovidethenecessaryprotec:ionagains.alossofcoolantflowincidentandareactuatedby:1.Lowvoltageonpumppowersupplybus2.Pumpcircuitbreakeropening(lowfrequencyon-pumppowersupplyn,busopenspumpcircuitbreaker)3.LowreactorcoolantflowThesetripcircuitsandtheirredundancyarefurtherdescribedinSec.ion7.2oftheFSAR,ReactorControlandProtec.ionSystem.Simultaneouslossofelectricalpowertoallreactorcoolantpumpsatfullpoweristhemostseverecredibleloss-of"coolantflowcondit;on.Forthisconditionreac.ortriptogetherwithflowsustainedbytheincr.iaofthecoolantandrotatingpumppar.swillbesuficienttopreventfuelfailureandreactorcoolantsystemoverpressureandtopreventheONBratiofromgoingbelowthelimitvalue.MethodofAnalsis-Thefollowingloss-of-flowcasesareanalyzed:1.Lossoftwopumpsfromareactor'oolantsystem,heatoutputof1520MWtwithtwoloopsoperating.0882L:614.1.6-1 2.Lossofonepumpfromareactorcoolantsystem,heatoutputof1520MWtwithtwoloopsooerating.Theirstcaserepresentstheworst,crediblecoolantflowloss.Thesecondcaseislesssevere.Lossofonepumpabovegpresetpowerlevelcausesareactortripbyalowflowsignal.Thepowerlevelabovewhichthistripoccursisassumedtobesetat49.~offullload.Thenormalpowersupplies.forthepumpsarethetwobusesconnectedtothegenerator,eachofwhichsuppliespowertooneofthetwopumps.Whenageneratorripoccurs,thepumpsareautomaticallytransferredtoabussuppliedfromexternalpowerlines.Therefore,thesimultaneouslossofpowertoallreac.orcoolantpumpsisahighlyunlikelyevent.Followinganyturbinetrip,wheretherearenoelectricalfaultswhichrequiretrippingthegeneratorfromthenetwork,thegeneratorremainsconnec.edtothenetworkforaleastoneminute.Sincebothpumpsarenotonthesamebus,asinglebusfaultwouldnotresultinthelossofallpumps.Thistransientisanalyzedbythreedigitalcomputercodes.Firs.,theLOFTRANcodeisusedtocalculatetheloopandcoreflowduring.hetransient,thetimeof,thereactortripbasedonthecalcula.edflow,thenuclearpowertransient,andtheprimarysys.empressureandtemperaturetransients.TheFACTRANcodeisthenusedtocalculatetheheatfluxtransientbasedonthenuclearpowerandflowfromLOFTRAN.0882L:614.1.6"2 Finally,theTHINCcodeisusedtocalculatetheDNBRduringthetransientbasedontheheatfluxfromFACTRANand'lowfromLOFTRAN.TheDNBRtransientspresentedrepresenttheminimumofthetypicalorthimblecell.This'accidentisanalyzedwiththeImprovedThermalDesignProcedureasdescribedinWCAP-8567(Reference6).PlantcharacteristicsandinitialconditionsarediscussedinSection14.InitialOperatinConditionsInitialreactorpower,pressure,andRCStemperatureareassumedtobeattheirnominalvalues~UncertaintiesininitialconditionsareincludedinthelimitDNBRasdescribedinWCAP-8567.ReactivitCoefficientsAconservativelylargeabsolutevalueoftheDoppler-onlypowercoefficientisused.Thisservestomaximizepowerlevelwhileitisdecreasingafterreactor'trip.ThetotalintegratedDopplerreactivity(powerdefect)between(4and100io'owerisassumedtobe0.0166k,consistentwithFigure14-2.Themostpositivevalueofthemoderatortemperaturecoefficient(+5pcm/~F)isassumed,sincethisresultsinthemaximumcorepowerduringtheinitialpartofthetransient,whentheminimumdeparturefromnucleateboilingratioisreached.FlowCoastdownTheflowcoastdownanalysisisbasedonamomentumbalancearoundeachreactorcoolantloopandacrossthereactorcore.Thismomentumbalance0882L:614.1.6-3

iscombinedwiththecontinuityequation,apumpmomentumbalanceandthepumpcharacteristicsandisbasedonhighestimatesofsystempressurelosses.Nosingleactivatefailureintheplantsystemsandequipmentwhicharenecessarytomitigatetheeffectsoftheaccidentwilladverselyaffecttheconsequencesoftheaccidentduringthetransientmostlyasaresultofthechangeoffuelgapconductance.Aconservativelyevaluatedoverallheattransferwasusedintheanalysis.ResultsReactorcoolantflowcoastdowncurvesareshowninFigure14.1.6-1.Figures14.1.6-1and14.1.6-3showthenuclearflux,theaveragechannelheatflux,andthehotchannelheatfluxresponseforthetwo-pumploss.Figure14.1.6-2showstheDNBratioasafunctionoftimeforthiscase.TheminimumWRB-1DNBratioisreached3.0secondsafterinitiationoftheincident.Figures14.1.6-4through14.1.6-6showthetransientforlossofonepumpwithbothloopsoperatingandFigure14.1.6-7showstheDNBratioasafunctionoftimeforthiscase.TheminimumDNBratiooccurs3.5secondsafterinitiationofthetransient.ConclusionsSinceDNBdoesnotoccurinanyloss-of-coolantflowincident,thereisnocladdingdamageandnoreleaseoffissionproductsintothereactorcoolant.Therefore,oncethefaultiscorrected,theplantcanbereturnedtoserviceinthenormalmanner.Theabsenceoffuelfailureswould,ofcourse,beverifiedbyanalysisofreactorcoolantsamples.0882L:614.1.6-4

LockedRotorAccidentAhypotheticaltransientanalysisisperformedforthepostulatedinstantaneousseizureofareactorcoolantpumprotor.Flowthroughthereactorcool'antsystemisrapidlyreduced,leadingtoareactortriponalow-flowsignal.Followingthetrip,heatstoredinthefuelrodscontinuestopassintothecorecoolant,causingthecoolanttoheatupandexpand.Atthesametime,heattransfertotheshellsideofthesteamgeneratorisreduced,firstbecausethereducedflowresultsinadecreasedtubesidefilmcoefficientandthenbecausethereactorcoolantinthetubescoolsdownwhiletheshellsidetemperatureincreses(turbinesteamflowisreducedtozerouponplanttrip).Therapidexpansionofthecoolantinthereactorcore,combinedwiththereducedheattransferinthesteamgenerator,causesaninsurgeintothepressurizerandapressureincreasethroughoutthereactorcoolantsystem.Theinsurgeintothepressurizercompressesthesteamvolume,actuatestheautomaticspraysystem,opensthepower-operatedreliefvalves,andopensthepressurizersafetyvalves,inthatsequence.Thetwopower-operatedreliefvalvesaredesignedforreliableoperationandwouldbeexpectedtofunctionproperlyduringtheaccident.However,forconservatism,theirpressure-reducingeffect,aswellasthepressure-reducingeffectofthespray,isnotincludedintheanalysis.MethodofAnalsisTwodigitalcomputercodesareusedtoanalyzethistransient.TheLOFTRANcodeisusedtocalculatetheresultingloopcoreandflowtransientsfollowingthepumpseizure,thetimeofreactortripbasedonloopflowtransients,andthenuclearpowerfollowingreactortrip,andtodeterminepeakpressure.ThethermalbehaviorofthefuellocatedatthecorehotspotisinvestigatedusingtheFACTRANcode,whichusesthecoreflowandnuclearpowercalculatedbyLOFTRAN.TheFACTRANcodeincludesafilmboilingheattransfercoefficient.0882L:614.1.6-5 I

Onecaseisanalyzedwithbothloopsoperatingandonelockedrotor.Atthebeginningofthepostulatedlockedrotoraccident(i.e.,atthetimetheshaftinoneofthereactorcoolantpumpsisassumedtoseize),theplantisassumedtobeinoperationunderthemostadversesteady"stateoperatingconditionswithrespecttothepressure,i.e.,maximumsteady-statepowerlevel,maximumsteady-statepressure(2280psia),andmaximumsteady-statecoolantaveragetemperature.Thelockedrotoreventisnotanalyzedwithaconsequentiallossofoffsitepower.AttheR.E.Ginnaplant,thegeneratorbreakerswill.notopenuntiloneminuteafterthelossofoffsitepower.Thus,powerwillbemaintainedtotheintactreactorcoolantpumpthroughoutthelimitingportionofthetransient.Thisiswithinthefirst10secondswhenthepeakcladtemperatureoccurs.Forthepeakpressureevaluation,theinitialpressureisconservativelyestimatedas30psiabovenominalpressure(2250psia)toallowforerrorsinthepressurizerpressuremeasurementandcontrolchannels.Thisisdonetoobtainthehighestpossibleriseinthecoolantpressureduringthetransient.Toobtainthemaximumpressureintheprimaryside,conservativelyhighlooppressuredropsareaddedtothecalculatedpressurizerpressure.Thepressure"responseshowninFigure'N14.1.6-9istheresponseatthepointinthereactorcoolantsystemhavingthemaximumpressure.EvaluationofthePressureTransient-Afterpumpseizure,theneutronfluxisrapidlyreducedbycontrolrodinsertioneffect..Rodmotionisassumedtobeginonesecondaftertheflowintheaffectedloopreaches87%ofnominalflow.Nocreditistakenforthepressure-reducingeffectofthepressurizerreliefvalves,pressurizerspray,steamdump,orcontrolledfeedwaterflowafterplanttrip.Althoughtheseoperationsareexpectedtooccurandwouldresultinalowerpeakpressure,anadditionaldegreeofconservatismisprovidedbyignoringtheireffect.0882L:614.1.6-6 N

Thepressurizersafetyvalvesarefullopenat2575psia,andtheirtotalcapacityforsteamreliefis20ft/s.3Evaluationof

DearturefromNucleateBoilinintheCoreDurintheAccident-Forthisaccident,

departurefromthenucleateboilingisassumedtooccurinthecore,andtherefore,anevaluationoftheconsequencewithrespecttofuelrodthermaltransientsisperformed.Resultsobtainedfromanalysisofthishotspotconditionrepresenttheupper1-imitwithrespecttocladtemperatureandzirconium-waterreaction.Intheevaluation,therodpoweratthehotspotisassumedtobethreetimestheaveragerodpower(Fg3)attheinitialcorepowerlevel.FilmBoil,inCoefficient-ThefilmboilingcoefficientiscalculatedintheFACTRANcodeusingtheBishop-Sandberg-Tongfilmboilingcorrelation.Thefluidpropertiesareevaluatedatfilmtemperture,whichistheaveragebetweenthewallandbulktemperatures.Theprogramcalculatesthefilmcoefficientateverytimestep,basedonthe.actualheattransferconditionsatthetime.Theneutronflux,systempressure,bulkdensity,andmassflowrateasafunctionoftimeareusedasprograminput.Forthisanalysis,theinitialvaluesofthepressureandthebulkdensityareusedthroughoutthetransient,sincetheyarethemostconservativewithrespecttocladtemperatureresponse.Forconservation,departurefromnucleateboilingwasassumedtostartatthebeginningoftheaccident.FuelCladGaCoefficient-Themagnitudeandthetimedependenceoftheheattransfercoefficientbetweenfuelandclad(gapcoefficient)haveapronouncedinfluenceonthethermalresults.Thelargerthevalueofthegapcoefficient,themoreheatistransferredbetweenthepelletandtheclad.Basedoninvestigationsoftheeffectofthegapcoefficientonthemaximumcladtemperatureduringthetransient,thegapcoefficientisassumedtoincreasefromastedy-statevalueconsistentwithaninitialfueltemperatureto10,000Btuperhour-square0882L:614.1.6-7 feet-Fattheinitiationofthetransient.Thus,thelargeamountofenergystoredinthefuelbecauseofthesmallinitialvalueisreleasedtothecladattheinitiationofthetransient.Zirconium-SteamReaction-Thezirconium-steamreactioncanbecomesignificantaboveacladtemperatureof1,800'F.TheBaker-Justparabolicrateequationshownbelowisusedtodefinetherateofthezirconium-steamreaction:26d~w333w30~45000dt1.986Twhere:w=amountreacted(mg/cm)2t=time(seconds)T=temperature('F).Thereactionheatis1,510cal/gm.ResultsFigure14.1.6"18andFigure14.1.6-9showthenuclearpower,coreflow,andloopflowtransientsandFigure14.1.6-18showsthepressuri.zerpressuretransients.TheheatfluxandcladtemperaturetransientsaregiveninFigure14.1.6-10.TheresultsofthesecalculationsaresummarizedinTable14.1.6-2.ThesequenceofeventsisshowninTables14.1.6-1and14.1.6-3.0882L:614.1.6-8 ConclusionsSincethepeakreactorcoolantsystempressure(2836psia)reachedduringanyofthetransientsislessthan120Kofdesignpressuretheintegrityoftheprimarycoolantsystemisnotendangered.Thisvaluecanbeconsideredanupperlimit,sincetheassumptionsusedinthe.analysisareconservative.Sincethepeakcladsurfacetemperature(2176'F)calculatedforthehotspotduringthemoreseveretransientremainsconsiderablylessthan2,700'Fandtheamountofzirconium-waterreactionissmall,thecoreremainsinplaceandintactwithnoconsequentiallossofcorecoolingcapability.0882L:614.1.6-9 TABLE14.1.6"1TIMESEQUENCEOFEVENTSFORLOSSOFREACTORCOOLANTFLOWCaseEventTimeofEachEventSecondsa.Partiallossofreactorcoolantflow(twoloopsoperating,onepumpcoastingdown)CoastdownbeginsLowflowreactortrip1.27Rodsbegintodrop2.27MinimumDNBRoccurs3.5b.CompletelossofforcedreactorcoolantflowBothoperatingpumpslosepowerandbegincoastingdownReactorcoolantpumpundervoltagetrippointreachedRodsbegintodrop1.5MinimumDNBRoccurs3.00882L:614.1.6-10

TABLE14.1.6-2SUMMARYOFLIMITINGRESULTSFORLOCKEDROTORACCIDENTMaximumReactorCoolantSystemPressure(psia)2836MaximumCladdingTemperature('F)CoreHotSpot2176Zr-H20ReactionatCoreHotSpot(5byweight).99350882L:614.1.6-11

TABLE14.1.6-3TIMESEQUENCEOFEVENTSFORLOCKEDROTORINCIDENTEventTimeofEachEventSecondsRotorononepumplocksLowflowtrippointreached.09Rodsbegintodrop1.09MaximumRCSpressureoccurs3.20Maximumcladtemperatureoccurs3.410882L:614.1~6-12 Figure14.1.6-1~irmaFull'psofFlowt.2CCO.<0000t:2OCOt.COCO'.20000X.CCCCCIA'VIva,2CCCC-CPCPCL(SEC)CICIChCt14.1.6-13 Figure14.1.6-2GinnaFullLossofFlowZICOOr23'.CIA~~~QCOO.ZCCO.C.tOO:0'.>cQcQ,COO':oP(CAR~Agel,gCCC(SEU14.1.6-14

Figure14.1.6-3Gr)pQu1IQ55!.2NQ1.0000.60000p,~ro.,eC.'nanncl,IdQCC1;CCCC..CCOQC4%~QQQQ%CCgus>A~-(14.1.6-15

Figure14.1.6-4GinnaPartialLossofF1ow~libIII~IIIhOIIA0II50000IO00200000.0IIlM~'IT000wl50000I'IF0000+nnn2'NOOfr00CI7lltE<SEO14.1.6-16 Figure14.1.6-5GinnaPartialLossof.Flow~EllIl8F009)111I1P82".pp8!pppZQOOpt".00p~oqpn~1PP~)IlI1I1I~~!".Qpp0900060000~nppp29000f0.0CICI.(Hf.5Eil14.1.6-17 0

Figure14.1.6-6pinnaPar-ialLssofF'ow,I\A(~:".000~?CCQQ+A>8"a.c.'g~he~aaelSCQQQF000020000~)IlhQ~~:0000OhQQPSpoonipppp20900IIIIggrChcahne(00ICPCT(meCie~>14.1.6-18

Figure14.1.6-7CI~Q>(t<El5cCl14.1.6-19

Figure14.1.6-8GinnaLockedRotor2.0000~7CQn!SQQQ'QQ3I.00007SQQQ~cSQQQQ250000.0~2tin0~nQQQ.80000X'60000ClF0000Xn200000.0CI~5OQtO%sf5='4.1.6-20 Figure14.1.6-9GonnaLockedRotor20<<'..,0000>"OCSCOOQ25CQOn-25000IfbllQIl<p,g($(=bLCCP2800.0O2500.02<00.Q2200.02000.0!800,0CICICIC7CICICICICIaDTtv((SEC)14.1.6-21

Figure14.1.6-10GinnaLockedRotor!,@VVVl.00001ISO0004X'ICLS00004F0000tI20000jI0.022hh20000tII'.1S0,0~I:S00.l'tIl2S0.9ViI1000004838OTlg'SEC)14.1.6-22 14.1.8LossofExternalElectricalLoadTheplantisdesignedtoaccepta50Klossofelectricalloadwhileoperatingatfullpoweroracompletelossofloadwhileoperatingbelow50%powerwithoutactuatingareactortrip.Theautomaticsteambypasssystemwith405steamdumpcapacitytothecondenserisabletoaccommodatethisloadrejectionbyreducingthetransientimposeduponthereactorcoolantsystem.Thereactorpowerisreducedtothenewequilibriumpowerlevelatarateconsistentwiththecapabilityoftherodcontrolsystem.Shouldthereactorsufferacompletelossofloadfromfullpower,thereactorprotectionsystemwouldautomaticallyactuateareactortrip.Themostlikelysourceofacompletelossofloadonthenuclearsteamsupplysystemisatripoftheturbine-generator.Inthiscase,thereisadirectreactortripsignalderivedfromeithertheturbineautostopoilpressureoraclosureoftheturbinestopvalves,providedthereactorisoperatingabove505power.Reactortemperatureandpressuredonotincreasesignificantlyifthesteambypasssystemandpressurizerpressurecontrolsystemarefunctioningproperly.However,theplantbehaviorisevaluatedforacompletelossofloadfromfullpowerwithoutadirectreactortrip,primarilytoshowtheadequacyofthepressurerelievingdevicesandalsotoshowthatnocoredamageoccurs.Thereactorcoolantsystemandsteamsystempressurerelievingcapacitiesaredesignedtoensurethesafetyoftheplantwithoutrequiringtheautomaticrodcontrol,pressurizerpressurecontrol,and/orsteambypasscontrolsystems.MethodofAnalsisThetotallossofloadtransientsareanalyzedbyemployingthedetaileddigitalcomputerprogramLOFTRAN.Theprogramsimulatestheneutron0882L:614.1.8-1

kinetics,reactorcoolantsystem,pressurizer,pressurizerreliefandsafetyvalves,pressurizerspray,steamgenerator,andsteamgeneratorsafetyvalves.Theprogramcomputespertinentplantvariables,includingtemperatures,pressures,andpowerlevel.Inthisanalysis,thebehavioroftheunitisevaluatedforacompletelossofsteamloadfrom100Koffullpowerwithoutdirectreactortrip,primarilytoshowtheadequacyofthepressure-relievingdevicesandalsotodemon'stratecoreprotectionmargins.ThisaccidentisanalyzedwiththeImprovedThermalDesignProceduresinWCAP-8567,Reference6(maintext).PlantcharacteristicsandinitialconditionsarediscussedinSection14.1.Initial0eratinConditions-Theinitialreactorpowerandreactorcoolantsystemtemperaturesareassumedattheirnominalvalues.UncertaintiesininitialconditionsareincludedinthelimitDNBRasdescribedinWCAP-8567.ModeratorandDolerCoefficientsofReactivit-Theloss-of-loadaccidentisanalyzedwithbothmaximumandminimumreactivityfeedback.ThemaximumfeedbackcasesassumealargenegativemoderatortemperaturecoefficientandthemostnegativeDopplerpowercoefficient.Theminimumfeedbackcasesassumepositivemoderatortemperaturecoefficient(+5pcm/F)andtheleastnegativeDopplercoefficient.ReactorControl-Fromthestandpointofthemaximumpressuresattained,itisconservativetoassumethatthereactorisinmanualcontrol.SteamRelease'-Nocreditistakenfortheoperationofthesteamdumpsystemorsteamgeneratorpower-operatedreliefvalves.Thesteam0882L:614.1.8-2

generatorpressurerisestothesafetyvalvesetpoint,wheresteamreleasethroughsafetyvalveslimitssecondarysteampressureatthesetpointvalue.PressurizerSraandPower-0cratedReliefValves-Twocases,for,bothmaximumandminimumfeedback,areanalyzed.a.Fullcreditistakenfortheeffectofpressurizersprayandpower-operatedreliefvalves,inreducingorlimitingthecoolantpressure.b.Nocreditistakenfortheeffectofpressurizersprayandpower-operatedreliefvalvesinreducingorlimitingthecoolantpressure.Safetyvalvesareoperable.FeedwaterFlow-Mainfeedwaterflowtothesteamgeneratorsisassumedtobelostatthetimeoflossofexternalelectricalload.Reactortripisactuatedbythefirstreactorprotectionsystemtripsetpointreached,withnocredittakenforthedirectreactortriponturbinetrip.ResultsThetransientresponsesforatotallossofloadfromfull"poweroperationareshownforfourcases-twocasesforminimumreactivityfeedbackandtwocasesformaximumreactivityfeedbackillustratedinFigures14.1~8-1through14.1.8-12.Figures14.1.8-1through14.1.8-3showthetransientresponsesforthetotalloss-of-steamloadwithminimumreactivityfeedback,assumingfullcreditforthepressurizersprayandpressurizerpower-operatedreliefvalves.Nocreditistakenforthesteamdump.0882L:614.1.8-3

Thereactoristripped.bythehighpressurizerpressuresignal.Theminimumdeparturefromnucleateboilingratioiswellabovethelimitvalue.Thepressurizersafetyvalvesarenotactuated.Figures14.1.8-4through14.1.8-6showtheresponseforthetotalloss-of-steamloadwithalargenegativemoderatortemperaturecoefficient.Astemperatureincreasesnuclearpowerdecreasesduetonegativereactivityfeedback.Powerthenstabilizesatalowerpowerleveluntilthelowsteamgeneratorleveltripsetpointisreached.TheDNBRincreasesthroughoutthetransientandneverdropsbelowitsinitialvalue.Pressurizerreliefvalvesandsteamgeneratorsafetyvalvespreventoverpressurizationinprimaryandsecondarysystems,respectively.Thepressurizersafetyvalvesarenotactuatedforthiscase.Followingthelowsteamgeneratorwaterlevelreactortrip,auxiliaryfeedwaterwouldbeusedtoremovedecayheatwiththeresultslessseverethanthosepresentedinSection14.1.9oftheFSAR,LossofNormalFeedwaterFlow.IThetotallossofloadaccidentwasalsostudiedassumingtheplanttobeinitiallyoperatingat100%offullpower,withnocredittakenforthepressurizerspray,pressurizerpower"operatedreliefvalves,orsteamdump.Thereactoristrippedonthehighpressurizerpressuresigna'1.Figures14.1.8-7through14.1.8-9showtheminimumfeedbacktransients.Theneutronfluxincreasesslightlyuntilthereactoristripped.Thedeparturefromnucleateboilingratioincreasesthroughoutthetransient.Inthiscase,thepressurizersafetyvalveisactuated.0882L:614.1.8-4 Figures14.1.8-10through14.1.8-12showthetransientswithmaximumfeedbackandallotherassumptionsbeingthesameasthoseinFigures14.1.8-7through14.1.8-9.Again,thedeparturefromnucleateboilingratioincreasesthroughoutthetransient,andthepressurizersafetyvalvesareactuated.ThecalculatedsequenceofeventsforthesefourcasesisshowninTable14.1.8-1.ConclusionsResultsoftheanalysesshowthattheplantdesignissuchthatatotallossofexternalelectricalloadwithoutadirectorimmediatereactortrippresentsnohazardtotheintegrityofthereactorcoolantsystemorthemainsteamsystem.Pressure-relievingdevicesincorporatedinthetwosystemsareadequatetolimitthemaximumpressureswithinthedesignlimits.Theintegrityofthecoreismaintainedbyoperationofthereactorprotectionsystem;i.e.,thedeparturefromnucleateboilingratioismaintainedabovethelimitvalue.0882L:614.1.8-5 TABLE14.1.8"1TIMESEQUENCEOFEVENTSFORLOSSOFEXTERNALELECTRICALLOADCaseEventTimeofEachEventSecondsa.Withpressurizercontrol(minimumfeedback)LossofelectricalloadHighpressurizerpressurereactortrippointreached12.6Rodbeginstodrop14.6Peakpressurizerpressureoccurs16.0Minimumdeparturefromnucleateboilingratiooccursb.Withpressurizercontrol(maximumfeedback)LossofelectricalloadPeakpressurizerpressureoccurs13.00882L:6P14.1.8"6 CaseTABLE14.1.8-1(continued)EventTimeofEachEventSecondsLowsteamgeneratorlevelreactortrippoint81.3Rodsbegintodrop83.3Minimumdeparturefromnucleateboilingratiooccursc.Withoutpressurizercontrol(minimumfeedback)LossofelectricalloadHighpressurizerpressurereactor5.4trippointreachedRodsbegintodrop7.4Peakpressureoccurs9.0InitiationofreleasefromS/Gsafetyvalves13.0Minimumdeparturefromnucleateboilingratiooccurs*DNBRdoesnotdecreasebelowitsinitialvalue.0882L:614.1.8-7 CaseTABLE14.1.8-1(continued)EventTimeofEachEventSecondsd.Withoutpressurizercontrol(maximumfeedback)Lossofelectrical'loadHighpressurizerpressurereactortrippointreached05.3Rodsbegintodrop7.3Peakpressureoccurs8.0InitiationofreleasefromS/GsafetyvalvesMinimumdeparturefromnucleateboilingratiooccursDNBRdoesnotdecreasebelowitsinitialvalue.0882L:614.1.8-8

Figure14.1.8-1GinnaLossofLoadMinimum;edback.vithAuomatcPressure"ontro1I.2000XICCCCZCIeooooCI50000o,>COCO'.2CCCO1IIIITI0.0I.00003~000~I3.0000I2.5000+~'.0000I.500020QQCICICICI5cclCID14.1.8-9 Figure14.1.8-2GinnaLossofLoadMinimumFeedbackwithAutomaticPressureControl660.005l0.QO600.00550.00d5.6O.QO570.00~'cl0QO550F005<O.QO600.QO560.QO~560.005iO.00lIII520.00g500.QOClCIClClAJClCl,lÃK(5EC)aClClClOClCl14.1.8-10 Figure14.1.8-3GinnaLossofLoadMinimumFeedbackwithAutomaticPressureControI25DQ.Q2400.0)400hj2300.3~22CQ.Q4!e2!00.0tIZCOO.Qts400I',800.0t!700.0!I!OCO.'0400.COtaCO.QO-4J700.00I500.005n4.!CO.CO400.CDCICICIClCICICICICICIrlHf(SKC)

Figure14.1.8-4GinnaLossofLoadt<aximumFeedbackwithAutomaticPressureControl~AI>>~~CCQXOltlWlv>>v>>JhIvvgl>>vh2&i>>%.S000i000>>52.0050,2!040Z.0000l.SD4Q.).2000.oCIflN(lSCQ14.1.8-1g

Figure14.1.8-5GinnaLossofLoadMaximumFeedbackwithAutomaticPressureControl0\40AA[WAQCt'AA~V~;~n.n+'ih1IVtvfbi'(sgA~VevTLHs14.1.8-13 0

Figure14.1.8-6GinnaLossofLoadMaximumFeedback,vithAutomatic.PressureControl2>C".VAAllC'22"Q.V5glAAQ)AAAA~VVV~4AQA~AAA~~I+I~V1AV~~AAQQ4AA'lA~~V3illAAAV~lllAAQAAAA4V4AAAQ~V4AAAQTIRE(44)14.1.8-14

Figure14.1.8-7GinnaIossofLoad'linimumFeedback'AithouPressureContro12000'000.SOOOO.SOQQOyI,iCCCOCJ.20000RII+5.0000i,!CQO~.00003.!000g3.aaaaIIlIIj2.!000nnQQIIl.!0002CCQCICI'SEC)14.1.8-15

Figure14.1.8-8GinnaLossofLoadMin'.numFeedbac!<M:.hou.?ressureCcntro1520."0otp~004200.00<<III55ppp4l580.00tI570.004I5eO.CP~I550.00jIIII5~0.00SOO.OO5SO.PO<<560.00tCl540.00520.00500.00ClCIClClClClClC7ClClCCCCYlHE<5EC)14.1.8-16 Figure14.1.8-9GinnaLossofLoadMinimumFeedbackMithoutPressureControl2500.02400.0t2<00.04,2300.02200.9j42IhQhv2000.04!4CO.Q~F800.0I)00Q!000,00I300.00ycI400nP4.VE700."0CC500.CDinCO."0III400.COCIC5AyC)CIaC7CICI<SEC)14.1.8-17 II Figure14.1.8-10GinnaLossoiLoadMaximumFeedbackWithoutPressureControl!.2000!.0000.80000+I)OCCO"jt).40000I20000TI!.CCCOt!000~t.0000~13.!COOiI3.COCOj.III2.!OOC+II)%IQCIIIt0tlA~vV!.2000CIO1!20)14;1.3-18

Figure141'8-11GinnaLossofLoadMaximumFeedbackMithoutPressure'.Control820.00I8'.0.20~800.00I580.00~j1580.00~I5(llhQI560.00I550.005gOQIIt+I800"0580.00y580.0045io.00520.00~tQQhQCICI~qCCIC7t58C)14.1.8-19 Figure14.1.8-12GinnaLossofLoadMaximumFeedbackMithoutPressureControl2600.5ciaoaj2300,522CO.Of2'!00.052CCO.5!400.54'L800.0!7005'"CO0I400.50fSCO.CO4baal'I~I5,np<<pTICCI500.50+I400.5400.00oCtC4I620)14.1.8-20 e

14.1.10ExcessiveHeatRemovalDuetoFeedwaterTemperatureDecreaseThereductioninfeedwaterenthalpyisanothermeansofincreasingcorepowerabovefullpower.Suchincreasesareattenuatedbythethermalcapacityinthesecondary'plantandintheReactorCoolantSystem.Theoverpower-overtemperatureprotection(nuclearoverpowerandhTtrips)preventsanypowerincreasewhichcouldleadtoaDNBRlessthanlimit'(value.Anextremeexampleofexcessheatremovalbythefeedwatersystemisthe'ransientassociatedwiththeaccidentalopeningofthefee'dwaterbypassvalvewhichdivertsflowaroundthelowpressurefeedwaterheaters.Thefunctionofthisvalveistomaintainnetpositivesuctionheadonthemainfeedwaterpumpintheeventthattheheaterdrainpumpflowislost,e.g.,duringalargeloaddecrease.Intheeventofanaccidentalopeningthereisasuddenreductionininletfeedwatertemperature,tothesteamgenerators.Theincreasedsubcooling'willcreateagreaterloaddemandontheprimarysystemwhichcanleadtoareactortrip.Thethree-elementfeedwatercontrolsystemoperatestoregulatethefeedwaterflowandmaintainawaterlevelapproximatelyconstantinthesteamgenerator.Actionofthethree-wayboilercontrolunderemergencyconditionhasnobearingonsafetysinceemergencyfeedwaterisinjecteddownstreamofthecontrolvalves.However,thefeedwatercontrolvalvesareusedforfeedwaterlineisolation.Anysafetyinjectionsignalwillredunantlyisolatethe.feedwaterlinesbya)ventingthesupplyairtoallfeedwatercontrol.valves,causingvalvestoclose;andbyb)trippingoffthemainfeedwaterpumps,includingclosureofthefeedwaterdischargevalves.TheweteffectontheRCSduetoareductioninfeedwaterenthalpyissimilartotheeffectofincreasingsecondarysteamflow,i.e,thereactorwillreachanewequilibriumconditionatapowerlevel,correspondingtothenewsteamgeneratorhT.0882L:614.1.10-1 MethodofAnalsisThisaccidentisanalyzedusingtheLOFTRANcode.Thecodesimulatestheneutronkinetics,reactorcoolantsystem,pressurizer,pressurizerreliefandsafetyvalves,pressurizerspray,steamgenerator,steamgeneratorsafetyvalves,andfeedwatersystem.Thecodecomputes.pertinentplantvariables,includingtemperatures,pressures,andpowerlevel.ThistransientisanalyzedbyreducingthefeedwaterenthalpybytheamountcorrespondingtothelossIofonefeedwaterheater.Twocaseshavebeenanalyzedtodemonstratetheplantbehaviorintheeventofasuddenfeedwatertemperaturereductionresultingfromaccidentalopeningofthebypassvalve.'II1.Reactorcontrolinmanualwithmaximummoderatorreactivityfeedback.2.Reactorcontrolinautomaticwithmaximummoderatorreactivityfeedback.Thereactivityinsertionrateatnoloadfollowinganexcessivefeedwateraccidenthasalsobeencalculatedwiththefollowingassumptions:1.Astepincreaseinfeedwaterflowtoonesteamgeneratorfrom0tothenominalfullloadvalueforonesteamgenerator.2.Themostnegativereactivitymoderatorcoefficientatendoflife.0882L:614.1.10-2 I.f 3.Aconstantfeedwatertemperatureof70F.4.Neglectoftheheatcapacityofthereactorcoolantsystemandsteamgeneratorshellthickmetal.5.Neglectoftheenergystoredinthefluidoftheunaffectedsecondsteamgenerator..Continuousadditionofcoldfeedwaterafterareactortripispreventedsincethereductionofreactorcoolantsystemtemperature,pressure,andpressurizerlevelwillleadtotheactuationofsafetyinjectiononlowJpressurizerpressure.Thesafetyinjectionsignalwilltripthelmainfeedwaterpumpsandclosethefeedwaterpumpdischargevalvesaswellasclosethemainfeedwatercontrolvalves.ThisaccidentisanalyzedwiththeImprovedThermalDesignProcedureasdescribedin'eference12.PlantcharacteristicsandinitialconditionsarediscussedinSection14.1.Initialreactorpower,pressure,andRCStemperaturesareassumedtobeattheirnominalvalues.Uncertainties~ininitialconditionsareincludedinthelimitDNBRasdescribedinReference6.ResultsFigures14.1.10-1through14.4.10-3illustratethetransientwiththereactorintheautomaticcontrolmode.Duetotheactionofthecontrolrodsandmoderatorfeedback,thenuclearpowerincreaseswhiletemperatureandpressuredecreaseuntilasteady-,stateconditionisreached.Areductionindeparturefromnucleateboilingratioisexperienced,butthedeparturefromnucleateboilingratioremainsabovethelimitvalue.0882L:614.1.10-3

,J Figures14.1.10-4through14.1.10-6illustratethetransientwhenthereactorisassumedtobeinthemanualcontrolmode.Again,thecorepowerincreasesduetothedecreaseincoolantaveragetemperature.Thedeparturefromnucleateboilingratiodecreasesbutremainsabovethelimitvalue.Thefeedwaterenthalpydecreaseincidentissimilartoanexcessiveloadincreaseandisanoverpowertransientforwhichthefueltemperaturesrise.Whenareactortripdoesnotoccur,theplantreachesanewequilibriumconditionatahigherpowerlevelcorrespondingtotheincreaseinsteamflow.Atzeropower,fortheexcessivefeedwaterflowtoonesteamgenerator,g~7&themaximumreactivityinsertionratewascalculatedtobe4.5xl0hk/second.ThisislessthanthemaximumreactivityinsertionratelanalyzedinSection14.1.1,UncontrolledRCCAWithdrawalfromaaSubcriticalCondition.Itshouldbenotedthatiftheaccidentoccurswiththeplantjustcriticalatnoload,thereactorwillbetrippedby.thepowerrangefluxleveltrip(lowsetting)setatapproximately25K.AsshowninSection'4.1.1,theDNBremainsabovethelimitvalue.-iss"LS+ConclusionsIthasbeendemonstratedthat,forafeedwaterenthalpydecreaseatfullpower,minimumDNBRdoesnotfallbelowthelimitvalue..Atzeropower,theresultsarelesslimitingthanthosepresentedinSection14.1.1.0882L:614.1.10-4

Figure14.1.10-11.2000GinnaFeedwaterEnthalpyDecreaseAutomaticRodControlt.oooo~.80000cK.60000o.40000CI.200000.01.2000l.0000XIDCICIILJCC.80000.60OOO40000I.200000.0CIC7C)C)AJC)C)VlCICICICIC7C)C)CII/ICDAJ1TIVEtSEC)14.1.10-5 Figure14.1.10-2GinnaFeedwaterEnthalpyDecreasekAutomaticRodControl2500.02400.02300.0cc2200'2IQQ.02000.0g1400.0.1800.017.00.0I000.00900.00800.004JK700.00CD)eso.soa.500.00tQQ.QQCDCDCDCDCDCDCDCDCDCDCDCDCDCDCDAJTIME<SEC)14.1.10-6 Figure14.1.10-3GinnaFeedwaterfnthalpyDecreaseAutomaticRodControl610.Oo600.00550.00c)580.00570.00560.Oot550.00540.003.00002.75002.50002.2500c..00001.7500I.5000CDCDCDCDAJCDCDI/>CDCDCD(s<<)CDCDCDCDCDCDCDAJ14.1.10-7

Figure14.1.10-4!.2CCOGinnaFeedwaterEntha1pyDecreaseManua1RodControIi.OCCOt.SCCOOZ'D.60000IcD.40000t..20000-,II0.0:.20001.0000ZCD.80000CD.60000T.40000.200000.0CDCDCDCDPgCDCDCD~CDCDV1T'iCDCDCDCDHE(SEC)CDCDCDCD14.1.10-8

Figure14.1.10-5GinnaFeedwaterEnthalpyDecrease'I2500.0ManualRodControl2400.02300.0+III2200.02100.02000.0i800.OCL)800.0-$700.0!"OC.Qo8CQ.Co800.00LJ7glhhoJSCO.Oo7I.500.Qo4QO.OOCDCDCDCDCICDfVIflCD,CD'D(,SEC)CDCD14.1.1G-9

Figurel4.1.10-6ffGinnaFeedwaterEnthaloyOecreasemanualRodControl520.006I0.00~600.00TI5000~a580.00-570.00t.I560.001550.00Sao.CC-.3.00002.75002.5000T2.2500T2.00001.7500TI.S000~IC)CICIC)CCCCIClC)C)CDCDTIME(SEC)14.1.10-10 14.1.11ExcessiveLoadIncrease'ncidentAnexcessiveloadincreaseincidentisdefinedasarapidincreaseinsteamgeneratorsteamflowthatcausesapowermismatchbetweenthereactorcorepowerandthesteamgenerato'rloaddemand.Thereactorcontrolsystemisdesignedtoaccommodatea10%steploadincreaseand/ora5~perminuteramploadincrease(withoutareactortrip)intherangeof155to10(Cfullpower.Anyloadingrateinexcessofthesevaluesmaycauseareactortripactuatedbythereactorprotectionsystem.Iftheloadincreaseexceedsthecapabilityofthereactorcontrolsystem,thetransientisterminatedintimetopreventDNBRlessthanthelimitingvaluebyacombinationofthenuclearoverpowertripandtheoverpower-overtemperaturehTtrips.Anexcessiveloadincreaseincidentcouldresultfromeithe'ranadministrativeviolation,suchassteambypasscontrolorturbinespeedcontrol.Forexcessiveloadingbytheoperatororbysystemdemand,theturbineloadlimiterkeepsmaximumturbineloadbelow100Kratedload.Duringpoweroperation,steambypasstothecondenseriscontrolledbyreactorcoolantconditionsignals,i.e.,abnormallyhighreactorcoolanttemperatureindicatesaneedforsteambypass.Asinglecontrollermalfunctiondoesnotcausesteambypass;aninterlockisprovidedwhichblocksthecontrolsignaltothevalvesunlessalargeturbineloaddecreaseoraturbinetriphasoccurred.MethodofAnalsisThisaccidentisanalyzedusingtheLOFTRANcode.Thecodesimulatestheneutronkinetics,reactorcoolantsystem,pressurizer,pressurizerreliefandsafetyvalves,pressurizerspray,steamgenerator,steam0882L:614.1.11-1

generatorsafetyvalves,andfeedwatersystem.Thecodecomputespertinentplantvariables,includingtemperatures,pressures,andpowerlevel.Fourcasesareanalyzedtodemonstratetheplantbehaviorfollowinga105step-loadincreasefromratedload.Thesecasesareasfollows:1.Reactorcontrolinmanualwithminimummoderatorreactivityfeedback.2.Reactorcontrolinmanualwithmaximummoderatorreactivityfeedback.3.Reactorcontrolinautomaticwithminimummoderatorreactivityfeedback.4.Reactorcontrolinautomaticwithmaximummoderatorreactivityfeedback.Fortheminimummoderatorfeedbackcases,thecorehasa5.0pcm/'Fmoderatortemperaturecoefficientofreactivityand,therefore,theleastinherenttransientcapability.Forthemaximummoderatorfeedbackcases,themoderatortemperaturecoefficientofreactivityhasitsmostnegativevalue.Thisresultsinthelargestamountofreactivityfeedbackduetochangesincoolanttemperature.Aconservativelimitontheturbinevalveopeningisassumed,andallcasesarestudiedwithoutcreditbeingtakenforpressurizerheaters.ThisaccidentisanalyzedwiththeImprovedThermalDesignProcedureasdescribedinReference12.PlantcharacteristicsandinitialconditionsareasdiscussedinSection14.1.Initialreactorpower,pressure,.and0882L:614.1.11-2 RCStemperaturesareassumedtobeattheirnominalvalues.UncertaintiesininitialconditionsareincludedinthelimitDNBRasdescribedinReference6.ResultsFigures14.1.11"1through14.1.11-6illustratethetransientwiththereactorinthemanualcontrolmode.Fortheminimumfeedbackcase,thepositiveMTCcausesthenucl.earpowertodecreasewithtemperatureandpressureunti1areactortriponlowpressurizerpressureoccurs.Thisresultsinadeparturefromnucleateboilingratiothatincreasesaboveitsinitialvalue.For'hemaximumfeedback,manuallycontrolledcase,thereisanincreaseinreactorpowerduetothemoderatorfeedback.Areductionindeparturefromnucleateboilingratioisexperienced,butthedeparturefromnucleateboilingratioremainsabovethelimitvalue.Figures14.1.11-7through14.1.11-12illustratethetransientwhenthereactorisassumedtobeintheautomaticcontrolmode.Boththeminimumandmaximumfeedbackcasesshowthatcorepowerincreases,therebyreducingtherateofdecreaseincoolantaveragetemperatureandpressurizerpressure.Forboththeminimumandmaximumfeedbackcases,theminimumdeparturefromnucleateboilingratioremainsabovethelimitvalue.ThecalculatedsequenceofeventsisshowninTable14.1.11-1.Theexcessiveloadincreaseincidentisanoverpowertransientforwhichthefueltemperaturesrise.'Whenareactortripdoesnotoccur,theplantreachesanewequilibriumconditionatahigherpowerlevel'Icorrespondingtotheincreaseinsteamflow.ConclusionIthasbeendemonstratedthat,foranexcessiveloadincrease,theminimumdeparturefromnucleateboilingratioduringthetransientwillnotbebelowthelimitvalue.0882L:614.1.11-3 TABLE14.1.11"1TIMESEQUENCEOFEVENTSFOREXCESSIVELOADINCREASEINCIDENTCaseEventTimeofEachEventSecondsa.Manualreactorcontrol(minimumfeedback)10%steploadincreaseLowerpressurizerpressuretripreachedRodsbegintofallintocore213.9215.9'.Manualreactorcontrol(maximumfeedback)10%steploadincreaseEquilibriumconditionsreached(approximatetimesonly)50.0c.Automaticreactor10/ostepload'ncreasecontrol(minimumfeedback)Equilibriumconditionsreached(approximatetimesonly)35.0d.Automaticreactorcontrol(maximumfeedback)105steploadincreaseEquilibriumconditionsreached(approximatetimesonly)60.00882L:614.1.11-4 Figure14.1.11-1GinnaExcessLoadIncreaseMinimumFeedbackwithoutRodControll.2000z1.0000CIICI.80000II.60000c..l0000C4141.20000I.ZOOOl.0000XCIXII41.80000~60000.10000.200000.0CICIVlCICICI1IlCICICICImTIHK(SEC)14.1.11-5 Figure14.1.11-2GinnaExcessLoadIncreaseMinimumFeedbackwithoutRodContro1Z800.0Zioo,o2200.02200.0VlCC02100.02000.01800.0!800.01700.0$000.00800.00~m800.00700.00'4J600.00.oo.ao400.00300.00200.00.ao.aaClCICSCIC5C)<SC)sabirizsr)CIClCIAJC7CI14.1.11-6 o

Figure14.1.11-3GinnaExcessLoadIncreaseMinimumFeedbackwithoutRodControl620.00600.00580.00560.00SIO.00S20.00500.005.0001Ki.5000l.00003.50003.00002.0000!.SOOO1.2000CDCICICDCICICDCD,CICITAHE(SEC)CDCDAJCDCDCDhJCICICIm

Figure14.1.11-4GinnaExcessLoadIncreaseMaximumFeedbackwithoutRodControl1.2000,Il.0000gI.60000<(I.60000~a~<0000+CCI0.0I.0000XC.60000cIXCI~60000.10000II'i.200000.0CSCIys33s383000O000CICDClInC)C)AlAJit%TIME<SEC)14.1.11-8 Figure14.1.11-5GinnaExcessLoadIncreaseMaximumFeedbackMithoutRodControlCiUV.Vjlao.0C2300.0I+2200.02!00.02COO.01eco.0:eco.o4'.Iao.otI+I!000.00Sao.aoEJcoo.ao>CO.CO5sao.co5sao.oo+00.00OOCICICICIOCICICICInCIONIOCICICIOCIINIIIlCIOCICINInHE(SEC)14.1.11-9 Figure14.1.11-6GinnaExcessLoadIncreaseMaximumFeedbackwithoutRodControl620.00610.00,II600.00~I4I550.00~I560.00~c570.00y560.00550.005lO.003.00002.7500Z.2500Z.00001~7500l.5000I:9888OCI3CIvtCIOCIOVlCIOAJCIAJOgCIOCICImCIrtlCICIO3PPE(SEC)14.1.11-10 Figure14.1.11-7GinnaExcessLoadIncreaseMinimumFeedbackwithAutomaticRodControlIJh0h<<xI000960hnh4l~a.600h09CC.C00.hgnnss00.0~gh0h~hhh0Pn0h00.60000CCC0hh'Iao3CIVlgInhlIIIplTIRE(SKC)CICICI eFigure14.1.11-8GinnaExcessLoadIncreaseMinimumFeedbackwithAutomaticRodControlI2500.02100.0vs2300.0g22nn0<<00.0i2000"CCgl00.0l800.0l700.9l000.00600.00LI800.00100.00600.00II.500.00400.'0CICICICICICIAJ88C5CImCICICICITlHElSEC)14.1.11-12 Figure14.1.11-9GinnaExcessLoadIncreaseMinimumFeedbackwithAutomaticRodControl6ZQ.00610.00600.00550.00580.""c57"..56".".55L.:5l0.:::3.0000!.oooojZ.5000t.350041.50001I:QSBCIgOOOOI.OOO00OOV1OoooOOosooooooTlHK(5EC)14.1.11-13

Figure14.1.11-10GinnaExcessLoadIncreaseMaximumFeedbackwithAutomaticRodControlz1.0000.80000cc.60000o.<00004g.200000.0f.2000t.0000.80000a.60000.I0000I0.0OOInCIOOIno383OOOT?HE(SKC)14.1.11-14 Figure14.1.11-11GinnaExcessLoadIncreaseMaximumFeedbackwithAutomaticRodControl2100.02200.0C4m2200.0III2100.02000.01900.0l800.01700.0!000.00800.00le800.00'4J~oo.oocecoo.ooo.800.00Ioo,00ClCICICICIVlCICIOOOCIOhJCIClCICICImCIOOOOOmTfHKtSEC)

Figure14.1.11-12GinnaExcessLoadIncreaseMaximumFeedbackwithAutomaticRodContro1620.00610.00600.00580.004J560.00c570.00S60.00550.00540.003,%002.150020002.25002.0000K.750000000000>0CI8CICIovs8CIVtIJTIRE(SEC)00"0O0gO0mm14.1.11-16 14.2.5RuptureofaSteamPipeAruptureofasteampipeisassumedtoincludeanyaccidentwhichresultsinanuncontrolledsteamreleasefromasteamgenerator.Thereleasecanoccurduetoabreakinapipelineorduetoavalvemalfunction.Thesteamreleaseresultsinaninitialincreaseinsteamflowwhichdecreasesduringtheaccidentasthesteampressurefalls.TheenergyremovalfromtheReactorCoolantSystemcausesareductionofcoolanttemperatureandpressure.Withanegativemoderatortemperaturecoefficient,thecooldownresultsinareductionofcoreshutdownmargin.Ifthemostreactivecontrolrodisassumedtobestuckinitsfullywithdrawnposition,thereisapossibilitythatthecorewillbecomecriticalandreturntopowerevenwiththeremainingcontrolrodsinserted.Areturntopowerfollowingasteampiperuptureisapotentialproblemonlybecauseofthehighhotchannelfactorswhichmayexistwhenthemostreactiverodisassumedstuckinitsfullywithdrawnposition.Assumingthemostpessimisticcombinationofcircumstances.whichcouldleadtopowergenerationfollowingasteamlinebreak,thecoreisutimatelyshutdownbytheboricacidintheSafetyInjec~ionSystem.Theanalysisofasteampiperuptureisperformedtodemonstratethatwithastuckrodandminimallyengineeredsafetyfeatures,thecoreremainsinplaceandessentiallyintactsoasnottoimpaireffectivecoolingofthecore.AlthoughDNBandpossiblecladperforation(nocladmeltingorzirconium-waterreaction)followingasteampiperupturearenotnecessarilyunacceptable,thefollowinganalysis,infact,showsthatnoDNBoccursforanyrupture,assumingthatthemostreactiverodisstuckinitsfullywithdrawnposition.H0882L:614.2.5-1 Thefollowingsystems'providethenecessaryprotectionagainstasteampiperupture:1.SafetyInjectionSystemactuationon:1a.Twooutofthreepressurizerlowpressuresignals.b.Twooutofthreelowpressuresignalsinanysteamline.c.Twooutofthreehighcontainmentpressuresignals.2.Theoverpowertrips(neutronfluxandhT)andthereactortripoccurringuponactuationoftheSafetyInjectionSystem.3.Redundantisolationofthemainfeedwaterlines.Sustainedhighfeedwaterflowwouldcauseadditionalcooldown;thus,inadditiontothenormalcontrolactionwhichwi11closethemainfeedwatervalves,anysafetyinjectionsignalwillrapidlycloseallfeedwatercontrolvalves,tripthemainfeedwaterpumps,andclosethefeedwaterpumpdischargevalves.4.Tripofthefastactingsteamlineisolationvalves(designedtocloseinlessthanfivesecondswithnoflow)on:a.Oneoutofthetwosteamflowsignalsinthatsteamlineincoincidencewithanysafetyinjectionsignal.(Dualsetpointsareprovided,withthelowersetpointusedincoincidencewithtwoout,offourindicationsoflowreactorcoolantaveragetemperature.)0882L:614.2.5-2 b.Twooutofthreehighcontainmentpressuresignals.Eachsteamlinehasafastclosingisolationvalveandacheckvalve.Thesefourvalvespreventblowdownofmorethanonesteamgeneratorforanybreaklocationevenifonevalvefailstoclose.Forexample,forabreakupstreamoftheisolationvalveinoneline,closureofeitherthecheckvalveinthatlineortheisolationvalveintheotherlinewillpreventblowdownoftheothersteamgenerator.Steamflowismeasuredbymonitoringdynamicheadinnozzlesinsidethesteampipes.Thenozzles(16-in.IDversusapipediameterof28-in.ID)arelocatedinsidethecontainmentnearthesteamgeneratorandalsoservetolimitthemaximumsteamflowforanybreakfurtherdownstream.Inparticular,thenozzleslimittheflowforallbreaksoutsidethecontainment.MethodofAnalsisTheanalysisofthesteampiperupturehasbeenperformedtodetermine:1.Thecoreheatfluxandreactorcoolantsystemtemperatureandpressureresultingfromthecooldownfollowingthesteamlinebreak.TheLOFTRANcodehasbeenused.2.Thethermalandhydraulicbehaviorofthecorefollowingasteamlinebreak.Adetailedthermalandhydraulicdigital-computercode,THINChasbeenusedtodetermineifDNBoccursforthecoreconditionscomputedin(1)above.0882L:614.2.5"3 Thefollowingassumptionsweremade:l.A0.018shutdownreactivityfromtherodsatnoloadconditionswith2loopsinoperation.Thisistheend-of-lifedesignvalueincl'udingdesignmarginswiththemostreactiverodstuckinitsfullywithdrawnposition.Operationofrodclustercontrolassemblybanksduringcoreburnupisrestrictedinsuchawaythatadditionofpositivereactivityinasecondarysystemsteamreleaseaccidentwillnotleadtoamoreadverseconditionthanthecaseanalyzed.A0.0245shutdownreactivityisassumedforcaseswhereoneloopisinservice.2.Thenegativemoderatortemperaturecoefficientcorrespondingtotheendoflifecorewithallbutthemostreactiverodinserted.Thevariationofthecoefficientwithtemperatureandpressurehasbeenincluded.Thekversustemperatureat1000psiacorrespondingtothenegativemoderatortemperaturecoefficientusedisshowninFigure14.2.5-1.Incomputingthepowergenerationfollowingasteamlinebreak,thelocalreactivityfeedbackfromthehighneutronfluxintheregionofthecorenearthestuckcontrolrodhasbeenincludedintheoverallreactivebalance.ThelocalreactivityfeedbackiscomposedofDopplerreactivityfromthehighfueltemperaturesnearthestuckcontrolrodandmoderatorfeedbackfromthehighwaterenthalpynearthestuckrod.Forthecasesanalyzedwheresteamgenerationoccursinthehighflux.regionsofthecore,theeffectofvoidformationonthereactivityhasbeenincluded.TheeffectofpowergenerationinthecoreonoverallreactivityispresentedinFigure14.2.5-2.Thecurveassumesendoflifecoreconditionswithallrodsinexceptthemostreactiverodwhichisassumedstuckinitsfullywithdrawnposition.3.Minimumsafetyinjectioncapabilitycorrespondingtotwooutofthreesafetyinjectionpumpsinoperation.Twothousand(2000)ppmboronisassumedinthesafetyinjectionsystem.Thetimedelaysrequiredtosweepthelowconcentrationboricacidfromthesafety0882L:614.2.5-4 injectionpiping.priortothedeliveryoftheboronhavebeenincludedintheanalysis.Twentythousand(20,000)ppmboronisassumedinthecaseswithoneloopinservice.4.PowerpeakingfactorscorrespondingtoonestuckRCCAandnonuniformcoreinletcoolanttemperaturesaredethrminedatendofcorelife.Thecoldestcoreinlettemperaturesareassumedtooccurinthesectorwiththestuckrod.Thepowerpeakingfactorsaccountfortheeffectofthelocalvoidintheregionofthestuckcontrolrodassemblyduringreturntopowerphasefollowingthesteamlinebreak.Thisvoidinconjunctionwiththelargenegativemoderatorcoefficientpartiallyoffsetstheeffectofthestuckassembly.Thepowerpeakingfactorsdependuponthecorepower,temperature,pressure,and,flow,and,thus,aredifferentforeachcasestudied.5.Threecombinationsofbreaksizesandinitialplantconditionshavebeenconsideredindeterminingthecorepowerandreactorcoolantsystemtransient.a.Completeseveranceofapipeinsidethecontainmentattheoutletofthesteamgeneratoratinitialno-loadconditionswithoutsidepoweravailableandtwoloopsinservice.The'quivalentbreakareais4.6ft.b.Case(a)abovewithlossofoutsidepowersimultaneouswiththesteambreak.c.Abreakequivalenttosteamreleasethroughonesteamgeneratorsafetyvalvewithoutsidepoweravailableandtwoloopsinservice.d.Case(a)abovewithonlyoneloopinservice.e.Case(c)abovewithonlyoneloopinservice.0882L:614.2.5-5 Theseveranceofapipedownstreamofthesteamflowmeasuringnozzleisnotanalyzed.The.equivalentbreakarea(1.4ft)2islessthanthatofcase(a)andwouldresultinalessseverecooldown.Thus,thisbreakisboundedbycases(a)and(b).Thecasesaboveassumeinitialhotshutdownconditionswiththerodsinserted(exceptforonestuckrod)attimezero.Shouldthereactorbe'ustcriticaloroperatingatpoweratthetimeofasteamlinebreakthereactorwillbetrippedbythenormaloverpowerprotectionsystemwhenthepowerlevelreachesatrippoint.Followingatripatpowerthereactorcoolantsystemcontainsmorestoredenergythanatno"load,theaveragecoolanttemperatureishigherthanatno-loadandthereisappreciableenergystoredinthefuel.Thus,theadditionalstoredenergyisremovedviathecooldowncausedbythesteamlinebreakbeforethenoloadconditionsofreactorcoolantsystemtemperatureandshutdownmarginassumedintheanalysesarereached.Aftertheadditionalstoredenergyhasbeenremoved,thecooldownandreactivityinsertionsproceedinthesamemannerasintheanalyseswhichassumeno-loadconditionsattimezero.ResultsTheresultspresentedareaconservativeindicationoftheeventswhichwouldoccurassumingasteamlinerupture.Theworstcaseassumesthat.allofthefollowingoccursimultaneously.1.Minimumshutdownreactivitymarginequalto1.80%(2loopsinservice).Minimumshutdownreactivitymarginequalto2.45.o(1loopinservice).2.Themostnegativemoderatortemperaturecoefficentfortheroddedcoreatendoflife.3.Therodhavingthemostreactivitystuckinitsfullywithdrawnposition.0882L:614.2.5-6

4.Onesafetyinjectionpumpfailstofunctionasdesigned.CorePowerandReactorCoolantSstemTransientFigures14.2.5-3through14.2.5-7showthereactorcoolantsystemtransientandcoreheatfluxfollowingasteampiperupture(completeseverenceofapipe)attheexitofasteamgeneratoratinitialno-loadconditionswithtwoloopsinoperation.Thebreakassumedisthelargestbreakwhichcanoccuranywhereeitherupstreamordownstreamoftheisolationvalves.Offsitepowerisassumedavailablesuchthatfullreactorcoolantflowexists.Thetransientshownassumestherodsinsertedattime0(withonerodstuckinitsfullywithdrawnposition)andsteamreleasefrombothsteamgenerators.Shouldthecorebecriticalatnearzeropowerwhentheruptureoccurs,theinitiationofsafetyinjectionbylowsteamlinepressurewilltripthereactor.Steamreleasefromatleastonesteamgeneratorwillbepreventedbyeitherthecheckvalveorbyautomatictripofthefastactingisolationvalveinthesteamlinebythehighsteamflowsignalincoincidencewiththesafetyinjectionsignal.Evenwiththefailureofonevalve,releaseislimitedtonomorethansevensecondsforonesteamgeneratorwhi,lethesecondgeneratorblows'down.(Thesteamlineisolationvalvesaredesignedtobefullyclosedinlessthanfivesecondswithnoflowthroughthem.Withthehighflowexistingduringasteamlinerupture,thevalveswillcloseconsiderablyfaster.)Thecorebecomescriticalwiththerodsinserted(withthe.designshutdownassumingonestuckrod)at14.5seconds.Boronsolutionat2,000ppmentersthereactorcoolantsystemfromthesafetyinjectionsystem(initiatedautomaticallybythelowsteamlinepressure)at41.0secondswhichincludesthedelayrequiredtoclearthesafetyinjectionsystemlinesoflowconcentrationboricacid.Nocredithasbeentakenforthe2,000ppmboronwhichentersthereactorcoolantsystempriorthe2,000ppmboricacid.Thepeakcoreheatfluxis31%of1520Mwt.0882L:614.2.5-7

Figures14.2.5-,8through14.2.5-12showtheresponsesforcaseaassumingalossofoutsidepowerattime0whichthenresultsinareactorcoolantsystemflowcoastdown.Thesafetyinjectionsystemdelaytimeincludesthe-.timerequiredtostartasafetyinjectionpump-'nthediesel.Onlyonedieselisassumedtostart.Creditistakenforonlythesafetyinjectionflowenteringthecold-leglines,sincetheflowtothehotlegflowpathsarevalvedshut.Thepeakpoweris20Kofnominal.Figures14.2.5-13through14.2.5-17showtheresponsesforafailedsteamgeneratorsafetyvalvewithtwoloopsinoperation.Criticalityoccursat220seconds.Boronentersthecoreduetoalowpressurizerpressuresafetyinjectionsignalat200seconds.Figures14'.5-18through14.2.5-22showthetransientforadoubleendedruptureassumingoneloopinservice.Theloophavingtheaffectedsteamgeneratorisassumedtobeinoperation.Thesequenceofeventsissimilartothecasewithbothloopsinoperation.Thecorebecomescriticalat22.0seconds.Boronsolutionat20,000ppmentersthecoreat37.0seconds.Thepeakcoreheatfluxis27Kof1520NWth.ThetransientforafailedsafetyvalvewithoneloopinserviceispresentedinFigures14.2.5-23through14.2.5-26.Boronsolutionat20,000ppmentersthecoreat160seconds.Criticalitydoesnotoccur.ThesequenceofeventsforeachcaseispresentedinTable14.2.5-1.ConclusionADNBanalysiswasperformedforeachcase.ItwasfoundthatallcaseshaveaminimumDNBRgreaterthanthelimitvalue.TheanalysishasshownthatthecriteriastatedinSection14.2.5aresatisfied'lthoughDNBandpossiblecladdingperforationfollowingasteampiperupturearenotnecessarilyunacceptableandnotprecludedbythecriteria,theaboveanalysis,infact,showsthattheDNBdesignbasisismet'asstatedinSection4.0882L:614.2.5-8 Casea.TABLE14.2.5-1TIMESEQUENCEOFEVENTSFORSTEAMLINERUPTURETimeofEventEventSteamlinerupturesPressurizeremptiesCriticalityattainedBoronenterscore8.514.541.0Steamlinerupture;offsitepowerlostPressurizeremptiesCriticalityattainedBoronenterscore9.519.053.0C.SafetyvalvefailsopenPressurizeremptiesLowpressurizerpressureSIsetpointreachedBoronenterscore97100200Criticalityoccurs2200882L:614.2.5"9 TABLE14.2.5-1(Continued)TIMESEQUENCEOFEVENTSFORSTEAMLINERUPTURETimeofEventCaseEventSteamlinerupturesPressurizeremptiesCriticalityattainedBoronenterscoreSafetyvalvefailsopenPressurizeremptiesLowpressurizerpressureSIsetpointreachedBoronenterscore9.022.037.00.093.099.01600882L:614.2.5-10 FIGURE14.2.5-1GINNASTEAMLINERUPTURE1.041.031.021.011.00.99.98200300400COREAVERAGETEMPERATURE,'F14.2.5-11 Figure14.2.5-2GINNASTEAMLINERUPTURE2.01.81.61.41.21.0Cl40)C)SClCLGLO.8lg$Ol.4.20.1.2.3.4.5-fractionofpower14.2.5-12 FIGURE14.2.5-3.50000GINNASTEAMLINERUPTURE4.6ftBreakwithPower2LoopsinService2.ipoooCIILJC?:.30000.20000w.~pppp0.0.50000c.LpopoX.30000.20000C.toooo0.0COCIC)C)CtCDCCI1COCl.~W71HE(SEC)14.2,5-13 FIGURE14.2.5-4GINNASTEAMLINERUPTURE4.6ftBreakwithPower22LoopsinService2000,01750.01500.01250.01000.00CI750.00500..001000.00500.00-800.00700.00600.00500.00CI400.00300.00I/I200.00100.000.0CICICICICIC)CI'IAdCICICICICICICICICICITIME15E6)14.2.5-14 FIGURE14.2.5-5GINNASTEAMLINERUPTURE4.6ftBreakwithPower550.00500.00450.00400.00C)C)o35000IO300.00in$pgfFacetted250.00200.00600.00550.00500.00450.00lalChhhhCMM~vv350.00300.00250.00200.00C)CIC)ClCOCOCICOCVCOCOCOCDmC)CDCtC)COTlHE<SIC)14.2.S-1S FIGURE14.2.5-6GINNASTEAMLINERUPTURE4.6ftBreakwithPower2cCCCI2.5000.25002.0000l.7500l,5000l.2500l.0000.75000.50000.25000oClC7Vl2.5C002.25002.0000l.7500c~cays.<<vipl.2500l.0000z.75000.50000ID.25000IntactFaulted0.0000CICOOOC)CVCICIC)COIDC>IDC)COC)TIME(52C)14.2.5-16 FIGURE14.2.5-7GINNASTEANLINERUPTURE4.6ftBreakwithPower22500.02000.01000.00ZLJ0.0100Oc.0<000.'0<500.0500.00F00.00XcL300.00CD200.00CD\JIOO.000.0CDCDCDCDCDAJCDCDCDCDTIME<SEC>CDCDCDCD14.2.5-17 FIGURE14.2.5-86INNASTEAMLINERUPTURE4.6ftBreakw/oPower-2LoopsinService2.l00005.30000LJ~~.20000CI4.100000.0T'AI%15KO.NN00~.moo3.amo~100000.0CITINE(%C)14.2.5-18 FIGURE14.2.5-9GINNASTEAMLINERUPTURE4.6ftw/oPower-2LoopsinService22000.01750.0~gnOO.OM50.0~l000.00750.00flylSEC)1000.00500.00NO.008700.00NO.00gg400.00WA4g300,00IA200.00Oef00.000.0CS8AlTlME(SEC)C5CI14.2.5-19 FIGURE14.2.5-10GINNASTEAMLIHERUPTURE4.6ftw/oPower-2LoopsinService2550.00Intact't<50.00F00.00Im.~l300.00Faulted200.00C7CI(AC)CIClCl550.00<50.005F00.00c350.00300.00~5TtHE(SEC)ClCIClClClCl14.2.5-20 FIGURE14.5.2-11GINNASTEAMLINERUPTURE4.6ftw/0Power-2LoopsinService22.50002.25002.ON).7500).5e)51.2500),oooo.75000CI.50000.25N~0.0C)CIC)TTIC(5KC)2.50002.25002.0000).7500).5000I).2500).0000z.75000Intact0.0aulted88-.8gI3y3S%THE(SKC)14.2.5-21 FIGURE14.2.5-12GINNASTEAMLINERUPTURE4.6ftBreakw/outPower2~2500.02000.01000.00K0.0-1000'.0<000.0<500.0500.00F00.00Xa.300.00CD200.00100.000.0CDCDCDCDCDCDCDAlTlME<SEC>CDCDCDC)CDCD14.2.5-22 FIGURE14.2,5-13GINNASTEAMLINERUPTURE-FAILEDSAFETYVALVE.40000c%C).30000lLJ.20000~100000.0.50000.iooooxIDXla.30000I4J.2OOOO'.100000.0C)CICIC)C)ClC)CICImTIHE(SEC)14.2.5-23 FIGURE14.2.5-14GINNASTEAMLINERUPTURE-FAILEDSAFETYVALVE2LoopsinService2OOO.01750.015OO.01250.01000.00500.001000.00900.00w~&00.00700.00600.00laJo500.00o)cgF00.00K300.00200.00100.000.0ooooooooooAJooiiHE(SEC)oCt14.2.5-24 FIGUREj4,2.5GINNASTEAMLINERUPTURE-FAILEDSAFETYVALVE2LoopsinService550.00500.00o50.00I100.00F~<YEQo350.00I~o30000250.00200.00550.00500.00i50.00IOO.00350.00I300.00Z50.00oooCIoCIAloCIoTIHEtSEC)oooCIoCICICI14.2.5-25 FIGURE14,2.516GINNASTEANLIHERUPTURE-FAILEDSAFETYVALVE2zcppx2.00001.7500'1.50001.25001.0000.75000.50000Cl.250000.0CICIClCICICIoCICDClClCDmClClCIc5CICIClClCICDIDCl250002000'1000.000.01000.0<000.0%500.0CI'ICIClCDCDClCDCDClClClClClClCITIHE(SEC)14.2.5-26 FIGURE14.2.5-QGINNASTEAMLINERUPTURE-FAILEOSAFETYVALVE500.00400.00Xa-300.00CD200.00CDLIIOO.000.0CDCD'DCDAJCDCDCDmCDClCDCDCDCDCDCDC)C)CDTIME(SEC)142.5-2>

Figure14.2.5-18GinnaSteamlineRupture4.6ftBreakwithPower-OneLoopinService2K.l0000Clcl.34)000ILJK4R.20000.100000.0.IOOOOXCl.300M.20000.100000.0ClClCIAlTlHE<SEC)8ClClCl14.2.5-28

Figure14.2.5-19GinnaSteamlineRupture4.6ftBreakwithPower-OneLoopinService22000.01750.01500.01250.01000.00750.001000.00SOO.00800.00700.00600.00Q500.00cc100.00300.00200.00100.000.0NCIEDClEDClClAlT1HE{SEC)ClCIClClCIClClCl14.2.5-29 Figure14.2.5-20GinnaSteamlineRupture4.6ftBreakwithPower-OneLoopinService2550.00500.00i50.00400.009cD350.00I300.00250.00200.00550.00500.00i50.00ccIoo.00CD350.00I300.00250.00200.00CDCDCDCDCDCD"CDmCDCDCDillCTIME(5E()14.2.5-30 Figure14.2.5-21GinnaSteamlineRupture4.6ftBreakwithPower-OneLoopinService22.50002.25002.0000I.nOOl.5000t.moI.OOOO.75000A.500000.0AA8CCCOClCDCDIll2.2500K2.0000I.7500CDlCClaI.5000I.2500I.0000x.75000.50000o.2SO0OIntactFaulted0.0OOOOO000000OCIClClCIOOCDCIOCCJCClTIME(SEC)CDOCDCDCOOCRO.CNOO14.2.5-3l FIGURE14.2.5-22GINNASTEAMLINERUPTURE4.6ftBreakwithPower2OneLoopinService14.2.5-32 Figure14.2.5-23GinnaSteamlineRuptureIFailedSafetyYalve-OneLoopinServiceC2000.0l750.0III'5000l250.0~lON.00750.00l000.00900.00600.00700.00600.00500.00CIcg100.00g3N.00200.00l00.000.0CICICICIAJCICICICIm7lHE(SEC)CICICICI14.2.5-33 Figure14.2.5-24GinnaSteamlineRuptureFailedSafeyValve-OneLoopinService550.00500.00150.00IAcc100.00350.00I300.00250.00200.00550.00500.00't450.00F00.00350.009I300.00250.00200.00CDCDCICDC)CMCDCITtMKlSEC)CDC)IDCDCDqCDID14.2.5-34

FIGURE14.2.5-25GINNASTEAMLINERUPTUREFailedSafetyValve-OneLoopinServiceLSD625002.00001.7500gL5000It,2500<.0000.75000h.saoo0.0.a8814.2.5-35 4lnCDQVlKlCDV)PlC+'Cm(X~INVlCDPlIIChCDCX7Im0OaI/lIDO'CD 14.2.6RuptureofaControlRodMechanismHousing-RCCAEjectionInorderforthisaccidenttooccur,arupture'ofthecontrolrodmechanismhousingmustbepostulatedcreatingafullsystempressuredifferentialactingonthedriveshaft.TheresultantcorethermalpowerexcursionislimitedbytheDopplerreactivityeffectsoftheincreasedfuel'emperatureandterminatedbyreactortripactuatedbyhighnuclearpowersignals.Afailureofacontrolrodmechanismhousingsufficientto,allowacontrolrodtoberapidlyejectedfromthecoreisnotconsideredcredibleforthefollowingreasons:1.Eachcontrolroddrivemechanismhousingiscompletelyassembledandshop-testedat4100psi.2.Themechanismhousingareindividuallyhydrotestedto3105psigas'heyareinstalledonthereactorvesselheadtotheheadadapters,andcheckedduringthehydrotestofthecompletedreactorcoolantsystem.3.'tresslevelsinthe.mechanismarenotaffectedbysystemtransientsatpower,orbythethermalmovementofthecoolantloops.MomentsinducedbythedesignearthquakecanbeacceptedwithintheallowableprimaryworkingstressrangespecifiedbytheASMECode,SectionIII,forClassAcomponents.4.Thelatchmechanismhousingandrodtravelhousingareeachasinglelengthofforgedtype-304stainlesssteel.Thismaterialexhibitsexcellentnotchtoughnessatalltemperaturesthatwillbeencountered.Thejointsbetweenthelatchmechanismhousingandheadadapter,andbetweenthelatchmechanismhousingandrodtravelhousing,arethreadedjointsreinforcedbycanopytyperodwelds.0882L:614.2.6-1 NuclearOesinEvenifaruptureofaRCCAdrivemechanismhousingispostulated,theoperationofaplantutilizingchemicalshimissuchthattheseverityofanejectedRCCAisinherentlylimited.Ingeneral,thereactorisoperatedwiththeRCCA'sinsertedonlyfarenoughtopermitloadfol-low.Reactivitycha'ngescausedbycoredepletionandxenontransientsarecompensatedbyboronchanges.Further,thelocationandgroupingofcontrolRCCAbanksareselectedduringthenucleardesigntolessentheseverityofaRCCAejectionaccident.Therefore,shouldaRCCAbeejectedfromitsnormalpositionduringfullpoweroperation,onlyaminorreactivityexcursion,atworst,couldbeexpectedtooccur.However,itmaybeoccasionallydesirabletooperatewithlargerthannormalinsertions.Forthisreason,arodinsertionlimitisdefinedas,afunctionofpowerlevel.OperationwiththeRCCA'sabovethislimitguaranteesadequateshutdowncapabilityandacceptablepowerdistribution.ThepositionofallRCCA'siscontinuouslyindicatedinthecontrolroom.AnalarmwilloccurifabankofRCCA'sapproachesitsinsertionlimitorifoneRCCAdeviatesfromitsbank.Operatinginstructionsrequireborationatlowlevelalarmandemergencyborationatthelow-lowalarm.ReactorProtectionThereactorprotectionintheeventofarodejectionaccidenthasbeendescribedinReference4.Theprotectionforthisaccidentisprovidedbyhighneutronfluxtrip(highandlowsetting).TheseprotectionfunctionsaredescribedindetailinSection7.2oftheFSAR.0882L:614.2.6-2

EffectsonAdjacentHousinsDisregardingtheremotepossibilityoftheoccurrenceofaRCCAmech-anismhousingfailure,investigationshaveshownthatfailureofahousingduetoeitherlongitudinalorcircumferentialcrackingwouldnotcausedamagetoadjacenthousings.However,evenifdamageispostu-lated,itwouldnotbeexpectedtoleadtoamoreseveretransient,sinceRCCA'sareinsertedinthecoreinsymmetricpatterns,andcontrolrodsimmediatelyadjacenttotheworstejectedrodsarenotinthecorewhenthereactoriscritical.Damagetoanadjacenthousingcould,atworst,causethatRCCAnottofallonreceivingatripsignal;however,thisisalreadytakenintoaccountintheanalysisbyassumingastuckrodisadjacenttotheejectedrod.LimitinCriteriaThiseventisclassifiedasanANSConditionIVincident.DuetotheextremelylowprobabilityofaRCCAejectionaccident,somefueldamagecouldbeconsideredanacceptableconsequence.Comprehensivestudies,bothofthethresholdoffuelfailureandofthethresholdorsignificantconversionofthefuelthermalenergytomechanicalenergy,havebeencarriedoutaspartoftheSPERTprojectbythe'IdahoNuclearCorporation.ExtensivetestsofU02zirconiumcladfuelrodsrepresentativeofthoseinpressurizedwaterreactortypecoreshavedemonstratedfailurethresholdsintherangeof240to257cal/gm.However,otherrodsofasightlydifferentdesi.gnhaveexhibitedfailuresaslowas225cal/gm.TheseresultsdiffersignificantlyfromtheTREATresults,whichindicatedafailurethresholdof280cal/gm.Limitedresultshaveindicatedthatthisthresholddecreasesbyabout10%withfuelburnup.Thecladfailuremechanismappearstobemeltingforzeroburnuprodsandbrittle0882L:614.2.6-3

fractureforirradiatedrods.Alsoimportantistheconversionratioofthermaltomechanicalenergy.Thisratiobecomesmarginallydetectableabove300cal/gmforunirradiatedrodsand200cal/gmforirradiatedrods;catastrophicfailure(largefueldispersal,largepressurerise)evenforirradiatedrodsdidnotoccurbelow300cal/gm.Inviewoftheaboveexperimentalresults,criteriaareappliedtoensurethatthereislittleornopossibilityoffueldispersalinthecoolant,grosslatticedistortion,orsevereshockwaves.Thesecriteriaare:a.Averagefuelpelletenthalpyatthehotspotbelow200cal/gm.b.Averagecladtemperatureatthehotspotbelowthetemperatureatwhichcladembrittlementmaybeexpected(2700'F).c.Peakreactorcoolantpressurelessthanthatwhichcouldcausestressestoexceedthefaultedconditionstresslimits.d.Fuelmeltingwillbelimitedtolessthantenpercentofthefuelvolumeatthehotspoteveniftheaveragefuelpelletenthalpyisbelowthelimitsofcriterion(a)above.AnalsisofEffectsandConseuencesMethodofAnalysisThecalculationoftheRCCAejectiontransientisperformedintwostages,firstanaveragecorechannelcalculationandthenahotregioncalculation.Theaveragecorecalculationisperformedusingspatialneutronkineticsmethodstodeterminetheaveragepowergenerationwithtimeincludingthevarious.totalcorefeedbackeffects,i.e.,Doppler0882L:614.2.6"4

reactivityandmoderatorreactivity.Enthalpyandtemperaturetran-sientsinthehotspotarethendeterminedbymultiplyingtheaveragecoreenergygenerationbythehotchannelfactorandperformingafuelrodtransientheattransfercalculation.Thepowerdistributioncalcu-latedwithoutfeedbackispes'simisticallyassumedtopersistthroughoutthetransient.Adetaileddiscussionofthemethodofanalysiscanbefou'ndinReference4.AverageCoreAnalsisThespatialkineticscomputercode,TWINKLE(Reference4),isusedfortheaveragecoretransientanalysis.Thiscodesolvesthetwogroupneutrondiffusiontheorykineticequationinone,twoorthreespatialdimensions(rectangularcoordinates)forsixdelayedneutrongroupsandupto2000spatialpoints.Thecomputercodeincludesadetailedmultiregion,transientfuel-clad-coolantheattransfermodelforcalcu-lationofpointwiseDopplerandmoderatorfeedbackeffects.Inthisanalysis,thecodeisusedasaonedimensionalaxialkineticscode,sinceitallowsamorerealisticrepresentationofthespatialeffec~tsofaxialmoderatorfeedbackandRCCAmovement.However,sincetheradialdimensionismissing,itisstillnecessarytoemployverycon-servativemethods(describedinthefollowing)ofcalculatingtheejectedrodworthandhotchannelfactor.FurtherdescriptionofTWINKLEappearsinSection14.HotSotAnalsisInthehotspotanalysis,theinitialheatfluxisequaltothenominaltimesthedesignhotchannelfactor.Duringthetransient,theheatfluxhotchannelfactorislinearlyincreasedtothetransientvaluein0.1second,thetimeforfullejectionoftherod.Therefore,the0882L:614.2.6-5 assumptionismadethatthehotspotsbeforeandafterejectionarecoincident.Thisisveryconservative,sincethepeakafterejectionwilloccurinoradjacenttotheassemblywiththeejectedrod,andpriortoejectionthepowerinthisregionwillnecessarilybedepressed.IIThehotspotanalysisisperformedusingthedetailedfuel-andcladdingtransientheattransfercomputercode,FACTRAN(Reference2).ThiscomputercodecalculatesthetransienttemperaturedistributioninacrosssectionofametalcladU02fuelrod,andtheheatfluxatthesurfaceoftherod,usingasinputthenuclearpowerversustimeandthelocalcoolantconditions.Thezirconium-waterreactionisexplicitlyrepresented,andallmaterialpropertiesarerepresentedasfunctionsoftemperature.Aconservativepelletradialpowerdistributionisusedwithinthefuelrod.FACTRANusestheDittus-BoelterorJens-LottescorrelationtodeterminethefilmheattransferbeforeDNB,andtheBishop-Sandburg-Tongcorrela-tiontodeterminethefilmboilingcoefficientafterDNB.TheBSTcorrelationisconservativelyusedassumingzerobulkfluidquality.TheDNBratioisnotcalculated,insteadthecodeisforcedintoDNBbyspecifyingaconservativeDNBheatflux.Thegapheattran'sfercoefficientcanbecalculatedbythecode;however,itisadjustedinordertoforcethefullpowersteady-statetemperaturedistributiontoagreewiththefuelheattransferdesigncodes.FurtherdescriptionofFACTRANappearsinSection14.SstemOverressureAnalsisBecausesafetylimitsforfueldamagespecifiedearlierarenotexceeded,thereislittlelikelihoodoffueldispersalintothecool-ant.Thepressuresurgemaythereforebecalculatedonthebasisofconventionalheattransferfromthefuelandpromptheatgenerationinthecoolant.0882L:614.2.6-6 Thepressuresurgeiscalculatedbyfirstperformingthefuelheattransfercalculationtodeterminetheaverageandhotspotheatfluxversustime.Usingtheseheatfluxdata,aTHINC(Section4)calcula-tionisconductedtodeterminethevolumesurge.Fina'lly,thevolumesurgeissimulatedinaplanttransientcomputercode.Thiscodecalcu-latesthepressuretransienttakingintoaccountfluidtransportinthereactor:coolantsystemandheattransfertothesteamgenerators.Nocreditistakenforthepossiblepressurereductioncausedbytheassumedfailureofthecontrolrodpressurehousing.CalculationofBasicParametersInputparametersfortheanalysisareconservativelyselectedonthebasisofvaluescalculatedforthistypeofcore.Themoreimportantparametersarediscussedbelow.Table14.2.6-1presentstheparametersusedinthisanalysis.EjectedRodWorthsandHotChannelFactorsThevaluesforejectedrodworthsandhotchannelfactorsarecalculatedusingeitherthree-dimensionalstaticmethodsorbyasynthesismethodemployingone-dimensionalandtwo-dimensionalcalculations.Standardnucleardesigncodesareusedintheanalysis.Nocreditistakenforthefluxflatteningeffectsofreactivityfeedback.Thecalculationisperformedforthemaximumallowedbankinsertionatagivenpowerlevel,asdeterminedbytherodinsertionlimits.Adversexenondistributionsareconsideredinthecalculation.Appropriatemarginsareaddedtotheejectedrodworthandhotchannelfactorstoaccountforanycalculationaluncertainties,includinganallowancefornuclearpowerpeakingduetodensification.0882L:614.2.6-7 ReactivitFeedbackWeihtinFactorsThelargesttemperaturerises,andhencethelargestreactivityfeed-backs,occurinchannelswherethepowerishigherthanaverage.Sincetheweightofaregionisdependentonflux,theseregionshavehighweights.Thismeansthatthereactivityfeedbackislargerthanthatindicatedbyasimplechannelanalysis.Physicscalculationshavebeencarriedoutfortemperaturechangeswithaflattemperaturedistribu-tion,andwithalargenumberofaxialandradialtemperaturedistribu"tions.Reactivitychangeswerecomparedandeffectiveweightingfactorsdetermined.Theseweightingfactorstaketheformofmultiplierswhichwhenappliedtosinglechannelfeedbackscorrectthemtoeffectivewholecorefeedbacksfortheappropriatefluxshape.Inthisanalysis,sinceaone-dimensional(axial)spatialkineticsmethodisemployed,axialweightingisnotnecessaryiftheinitialconditionismadetomatchtheejectedrodconfiguration.Inaddition,noweightingisappliedtothemoderatorfeedback.Aconservativeradialweightingfactorisappliedtothetransientfueltemperaturetoobtainaneffective.fueltempera-tureasafunctionoftimeaccountingforthemissingspatialdimen-sion.Theseweightingfactorshavealsobeenshowntobeconservativecomparedtothree-dimensionalanalysis(Reference4).ModeratorandDolerCoefficientThecriticalboronconcentrationsatthebeginningoflifeandendoflifeareadjustedinthenuclearcodeinordertoobtainmoderatordensitycoefficientcurveswhichareconservativecomparedtoactualdesignconditionsfortheplant.Asdiscussedabove,noweightingfactorisappliedtotheseresults.0882L:614.2.6"8

TheDopplerreactivitydefectisdeterminedasfunctionofpowerlevelusingaone-dimensionalsteady-statecomputercodewithaDopplerweightingfactorof1.0.TheDopplerdefectusedisgiveninSection3.0.TheDopplerweightingfactorwillincreaseunderaccidentconditions,asdiscussedabove.DelaedNeutronFractionBCalculationsoftheeffectivedelayedneutronfraction(P)efftypicallyyieldvaluesno,lessthan0.70io'tbeginningoflifeand0.50%atendoflifeforthefirstcycle.Theaccidentissensitiveto5iftheejectedrodworthisequaltoorgreaterthan5asinzeropowertransients.Inordertoallowforfuturecycles,pessimisticestimatesofPof0.495atbeginningofcycleand0.43:oatendofcyclewereusedintheanalysis.TriReactivitInsertionThetripreactivityinsertionassumedisgiveninTable14.2.6-1andincludestheeffect~ofonestuckRCCA.Theshutdownreactivitywassimulatedbydroppingarodoftherequiredworthintothecore.Thestartofrodmotionoccurred0.5secondsafterthehighneutronfluxtrippointwasreached.Thisdelayisassumedtoconsistof0.2secondfortheinstrumentchanneltoproduceasignal,0.15secondforthetripbreakertoopenand0.15.secondforthecoiltoreleasetherods.Acurveoftriprodinsertionversustimewasusedwhichassumedthatinsertiontothedashpotdoesnotoccuruntil1.8secondsafterthestartoffall.Thechoiceofsuchaconservativeinsertionratemeans0882L:614.2.6-9

~l"*~~(

thatthereisoveronesecondafterthetrippointisreachedbeforesignificantshutdownreactivityisinsertedintothecore.Thisisaparticularlyimportantconservatismforhotfull-poweraccidents.'eactorProtectionReactorprotectionforarodejectionisprovidedbyhighneutronfluxtrip(highandlowsetting).Theseprotectionfunctionsarepartofthereactortripsystem.Nosinglefailureofthereactortripsystemwillnegatetheprotectionfunctionsrequiredfortherodejectionaccident,oradverselyaffecttheconsequencesoftheaccident.ResultsCasesarepresentedforbothbeginningandendoflifeatzeroandfullpower.1.BeinninofCcleFullPowerControlbankDwasassumedtobeinsertedtoitsinsertionlimit.Theworstejectedrodworthandhotchannelfactorwereconserva-tivelycalculatedtobe.40%6kand5.61respectively.Thepeakhotspotcladaveragetemperaturewas2543'F~Thepeakhotspotfuelcentertemperaturereachedmelting,wasconservativelyassumedat4990'F.However,meltingwas'restrictedtolessthan10%ofthepellet.2.BeinninofCcle,ZeroPowerForthiscondition,controlbankDwasassumedtobefullyinsertedandbanksBandCwereattheirinsertionlimits.Theworstejectedrodislocatedincontrolbank,Dandhasaworthof.78%6kandahotchannelfactorof7.80.Thepeakhotspotcladtemperaturereached2639F,thefuel.centertemperaturewas3861F.0882L:614.2.6-10

3.EndofCcleFul1PowerControlbankDwasassumedtobeinsertedtoitsinsertionlimit.Theejectedrodworthandhotchannelfactorswereconservativelycalculatedtobe.42%6kand5.69respectively.Thisresultedinapeakcladaveragetemperatureof2246F.Thepeakhotspotfueltemperaturereachedmeltingconservativelyassumedat4800~F.However,meltingwasrestrictedtolessthan10~ofthepellet.4.EndofCcleZeroPowerTheejectedrodworthandhotchannelfactorforthiscasewereobtainedassumingcontrolbank0tobefullyinsertedandbanksCandBattheirinsertionlimits.Theresultswere.95'o'hkand9.4'Frespectively.Thepeakcladaverageandfuelcentertemperatureswere2421and3449'F.TheDopplerweightingfactorforthiscaseissignificantlyhigherthanfortheothercasesduetotheverylargetransienthotchannelfactor.AsummaryofthecasespresentedaboveisgiveninTable14.2.6-1.Thenuclearpowerandhotspotfuelandcladte'mperaturetransientsfortheworstcasesarepresentedinFigures14.2.6-1'through14.2.6"2(beginning"of-lifefullpowerandbeginning-of-life'zeropower).ThesequenceofeventsforthesetwocasesispresentedinTable14.2.6-2.Forallcases,reactortripoccursveryearlyinthetransient,afterwhichthenuclearpowerexcursionisterminated.Asdiscussedpreviously,thereactorwillremainsubcriticalfollowingreactortrip.TheejectionofanRCCAconstitutesabreakintheReactorCoolantSystem,locatedinthereactorpressurevesselhead.Theeffectsandconsequencesofloss-of-coolantaccidentsarediscussedinSection14.3.FollowingtheRCCAejection,theoperatorwouldfollowthesame0882L:614.2.6"ll

emergencyinstructionsasforanyotherlossofcoolantaccidenttorecoverfromtheevent.FissionProductReleaseItisassumedthatfissionproductsarereleasedfromthegapsofallrodsenteringDNB.Inallcasesconsidered,lessthan10%ofth0rodsenteredDNBbasedonadetailedthree-dimensionalTHINCanalysis.PressureSureAdetail.edcalculationofthepressuresurgeforanejectionworthofonedollaratbeginningoflife,hotfullpower,indicatesthatthepeakpressuredoesnotexceedthatwhichwouldcausestresstoexceedthefaultedconditionstresslimits.Sincetheseverityofthepresentanalysisdoesnotexceedthe"worstcase"analysis,theaccidentforthisplantwillnotresultinanexcessivepressureriseorfurtherdamagetothereactorcoolantsystem.LatticeDeformationsAlargetemperaturegradientwillexistintheregionofthehotspot.Sincethefuelrodsarefreetomoveintheverticaldirection,differ-entialexpansionbetweeqseparaterodscannotproducedistortion.However,thetemperaturegradientsacrossindividualrodsmayproduceadifferentialexpansiontendingtobowthemidpointoftherodstowardthehottersideoftherod.CalculationshaveindicatedthatthisbowingwouldresultinanegativereactivityeffectatthehotspotsinceWestinghousecoresareunder-moderated,andbowingwilltendtoincreasetheunder-moderationatthehotspot.Sincethe14x14fueldesignisalsounder-moderated,thesameeffectwouldbeobserved.Inpractice,nosignificantbowingisanticipated,sincethestructuralrigidityofthecoreismorethansufficienttowithstandtheforcesproduced.Boilinginthehotspotregionwouldproduceanetflowawayfromthatregion.However,theheatfromthefuelisreleasedtothe0882L:614.2.6-12

waterrelativelyslowly,anditisconsideredinconceivablethatcrossflowwillbesufficienttoproducesignificantlatticeforces.Evenifmassiveandrapidboiling,sufficienttodistortthelattice,ishypotheticallypostulated,thelargevoidfractioninthehotspotregionwouldproduceareductioninthetotalcoremoderatortofuelratioandalargereductioninthisratioatthehotspot.Theneteffectwouldthereforebeanegativefeedback.Itcanbeconcludedthatnoconceivablemechanismexistsforanetpositivefeedbackresultingfromlatticedeformation.Infact,asmallnegativefeedbackmayresult.Theeffectisconservativelyignoredintheanalysis.ConclusionsConservativeanalysesindicatethatthedescribedfuelandcladdinglimitsarenotexceeded.Itisconcludedthatthereisnodangerofsuddenfueldispersalintothecoolant.Sincethepeakpressuredoesnotexceedthatwhichwouldcausestressestoexceedthefaultedconditionstresslimits,itisconcludedthatthereisnodangeroffurtherconsequentialdamagetothereactorcoolantsystem.Theanalyseshavedemonstratedthatthefissionproductrelease,asaresultofanumberoffuelrodsenteringDNB,islimitedtolessthan10%ofthefuelrodsinthecore.0882L:614.2.6"13

,TABLE14.2.6-1PARAMETERSUSEDINTHEANALYSISOFTHERODCLUSTERCONTROL"ASSEMBLYEJECTIONACCIDENTTimeinLifeParametersBeginningBeginningEndEndPowerlevel,percentEjectedrodworth,percenthkDelayedneutronfraction,percentFeedbackreactivityweightingTripreactivity,percenthkFbeforerodejectionqFafterrodejectionqNumberofoperationalpumpsMaximumfuelpelletaveragetemperature,'FMaximumfuelcentertemperature,,FMaximumcladaveragetemperature,'FMaximumfuelstoredenergy,cal/gMaximumfuelmelt,percentr102.40.491.34.02.55.61419049712543184<100.78).,491.4172.07.803422386126391450.01020.42.95.43.431.31.744.02.02.55.699.402'1372630994838344922462421160129<100.00882L:614.2.6-14 TABLE14.2.6-2TIMESEQUENCEOFEVENTSRCCAEJECTIONCasea.Beginning-of-Life,FullPowerEventInitiationofrodejectionPowerrangehighneutronfluxsetpointreachedTimeofEachEventSeconds0.00.03PeaknuclearpoweroccursRodsbegintofallintocore0.53PeakfuelaveragetemperatureoccursPeakcladtemperatureoccursPeakheatfluxoccurs2.002.00b.Beginning-of-Life,ZeroPowerInitiationofrodejection0.0Powerrangehighneutronfluxlowsetpointreached0.24PeaknuclearpoweroccursRodsbegintofallintocorePeakcladtemperatureoccursPeakheadfluxoccurs0.29/(0.742.14Peakfuelaveragetemperatureoccurs2.270882L:614'.6"15

~'

Figure14.2.6-1GinnaRCCAEjectionBeginningofLife,FullPower10..0ClCICIClClClClnOOVSCCChbOClOPnClmTIHEtSKC)6000.05000.04000.03000.02000.0)000.00.oe)<en'p.Fue]A.VgClad0.0ClClCCCOClClOCDCIOCDClOClOTIW(SEC)IA9.6-16 Figure14.2.6-2GinnaRCCAEjectionBeginningofLife,ZeroPowero10S-O.01C7CDCDCD3'8Iss-sCDeCDCDhlAJmTlHE<SEC)6000.05000.0loop.0poopopOOp0)000.000.0FuelCen~eFuelAvVg.CladCDtSKCiCDCDCD14.2.6-17

ATTACHMENTCLOCAACCIDENTANALYSISREVISEDFSARSECTIONS14.3.1/14.3.20882L:6C-1 A

TABLEOFCONTENTSSectionDescriptionPage14.3PrimarySystemPipeRuptures14.3.1-114.3.1LossofReactorCoolantFromSmallRupturedPipesorFromCracksinLargePipesWhichActuatesEmergencyCoreCoolingSystem14.3.1-114.3.1References14.3.1-714.3.2MajorReactorCoolantSystemPipeRuptures(LossofCoolantAccident)14.3.2-114.3.2References14.3.2-70458L:6 4/t1 LISTOFTABLESTableDescriptionPage14.3.1-)SmallBreak-TimeSequenceofEvents14.3.1"814.3.1-214.3.2-1SmallBreak-AnalysisInputandResultstLargeBreak-TimeSequenceofEvents)4.3.)"914.3.2-1014.3.2-2LargeBreak-AnalysisInputandResults)4.3.2-1114.3.2-3LargeBreak-ContainmentData14.3'-1214.3.2"4RefloodPassandEnergyRelease14.3.2-1514.3.2-5BrokenLoopAccumulatorYiassandEnergyRelease14.3.2-160458L:6 LISTOFFIGURESFigureDeseriptionPage14.3.1-)a14.3.)-lbHighHeadSafetyInjectionFlowRatefLowHeadSafetyInjectionFlowRate14.3.1-1014.3.1-1114.3.1-2HotRodAxialPowerShape14.3.1"1214.3.1"3DepressurizationTransient(6-Inch)14.3.1"1314.3.1-4CoreMixtureHeight(6-Inch)14.3.1"1414.3.1-5PeakCladTemperatureTransient(6-Inch)14.3.1-1514.3.1-6SteamFlowRate14.3.1-1614.3.1-7RodFilmCoefficients14.3.1-1714.3.1"8HotSpotFluidTemperature14.3.1-1814.3.)-9aDepressurizationTransient(4-Inch)14'.1-1914.3.1-9bDepressurizationTransient(8-Inch)14.3.1-2014.3.1-10aCoreMixtureHeight(4-Inch)14.3.1-2114.3.1-10b14.3'-llaCoreMixtureHeight(8-Inch)CladTemperatureTransient(4-Inch)14.3.1"2214.3.1"2314.3.1"1)bCladTemperatureTransient(8-Inch)14.3.1-2414.3.2-)aFluidequality-DECLG(CD=0.8)14.3.2-170458L:6

LISTOFFIGURES(continued)DescriptionPage14.B<@'luid.Quality-DECLG(CD=0.6)14.3.2"1814.~>,FluidQuality-DECLG(CD=0.4)14.3.2-1914.3'+zMassVelocity-DECLG(CD=0.8)14.3.2"2014.3~+~MassVelocity-,DECLG(CD=0.6)~'4.3.2"2114.3.Z>Mass,Velocity-DECLG(CD=0.4)14.3.2"2214.3.23a,HeatTransferCoefficient-DECLG(CD=0.8)14.3.2-2314.3.2-auHeatTransferCoefficient-DECLG(CD=0.6)14.3.2-2414.3.,2-~~HeatTransferCoefficient-DECLG(CD=0.4)14.3.2-25CorePressure-DECLG(CD=0.8)14.3.2"2614.32-4'4.3.2-4c;CorePressure"DECLG(CD=0.6)CorePressure-DECLG(CD=0.4)14.3.2-2714.3.2-2814.3.2-5a14.3.2"5b14.3.2-5cBreakFlowRate-DECLG(CD=0.8)BreakFlowRate-DECLG(CD=0')BreakFlopRyte-DECLG(CD=0.4)14.3.2-2914.3.2"3014.3.2-3114.3.2-6aCorePressureDrop-DECLG(CD=0.8)14.3.2"320458L:6 I0'/

LISTOFFIGURES(continued)FigureDescriptionPage14.3.2-1bFluidQuality-DECLG(CD=0.6)14.3.2-1814.3.2-1c14.3.2-2aFluidQuality-DECLG(CD=0.4)MassVelocity-DECLG(CD=0.8)14.3.2"1914.3.2-2014.3.2-2b14.3.2"2cMassVelocity-DECLG(CD=0.6)MassVelocity-DECLG(CD=0.4)14.3.2"2114.3.2"22)4.3.2-3a14.3.2"3bHeatTransferCoefficient"DECLG(CD=0.8)14.3.2-23lHeatTransferCoefficient-DECLG(CD=0.6)14.3.2-2414.3.2-3cHeatTransferCoefficient-DECLG(CD=0.4)14.3.2-2514.3.2-4aCorePressure-DECLG(CO=0.8)14.3.2-2614.3.2-4bCorePressure-DECLG(CO=0.6)14.3.2-2714.3.2"4cCorePressure-DECLG(CD=0.4)14.3.2-2814.3.2-5aBreakFlowRate-DECLG(CD=0.8)14.3.2-2914.3.2"5bBreakFlowRate-DECLG(CD=0.6)14.3.2-3014.3.2-5cBreakFlowRate-DECLG(CD=0.4)14.3.2-3114.3.2-6aCorePressureDrop-OECLG(CD=0.8)14.3.2-320458L:6

LISTOFFIGURES(continued)FigureDescriptionPage14.3.2-6bCorePressureDrop-DECLG(CD=0.6)14.3.2-3314.3.2-6cCorePressureDrop-DECLG(CD=0.4)14.3.2-3414.3.2-7aPeakCladTemperature-DECLG(CD=0.8)14.3.2-3514.3.2-7b14.3.2-7cPeakCladTemperature-DECLG(CD=0.6)PeakCladTemperature-DECLG(CD=0.4)14.3.2-3614.3.2-3714.3.2-8aFluidTemperature-DECLG(CD=0.8)14.3.2-3814.3.2-8b14.3.2-8cFluidTemperature-DECLG(CD=0.6)FluidTemperature-DECLG(CD=0.4)14.3.2-3914.3.2-4014.3.2-9aCoreFlow(TopandBottom)-DECLG(CD=0.8)14.3.2-4114.3.2-9bCoreFlow(TopandBottom)-DECLG(CD=0.6)14.3.2-4214.3.2-9cCoreFlow(TopandBottom)-DECLG(CD=0.4)14.3.2-4314.3.2-10aRefloodTransient-CoreInletVelocity-14.3.2-44DECLG(CD=0.8)14.3.2-10bRefloodTransient-CoreInletVelocity-14.3.2-45DECLG(CD=0.6)0458L:6 LISTOFFIGURES(continued)FigureDescriptionPage14.3.2-10cRefloodTransient-CoreInletVelocity-14.3.2-46DECLG(CD=0.4)14.3.2-11aRefloodTransient-CoreandDowncomerWaterLevels-DECLG(CD=0.8)14.3.2-4714.3.2"libRefloodTransient-CoreandDowncomerWaterLevels-DECLG(CD=0.6)14.3.2-4814.3.2-11cReflo'odTransient-CoreandDowncomerWaterLevels-DECLG(CD=0')14.3.2"4914.3.2-12aAccumulator.Flow(Blowdown)-DECLG(CD=0.8)14.3.2-5014.3.2-12bAccumulatorFlow(Blowdown)-DECLG(CD=0.6)14.3.2-5114.3.2"12cAccumulatorFlow(Blowdown)-DECLG(CD=0.4)14.3,2-5214.3.2-13aPumpedECCSFlow(Reflood)-(CD=0.8)14.3.2-5314.3.2-13bPumpedECCSFlow(Reflood)-(CD=0.6)14.3.2-5414.3.2"13cPumpedECCSFlow(Reflood)-(CD=0.4)14.3.2-5514.3.2-14aContainmentPressure-DECLG(CD=0.8)14.3.2-5614.3.2-14bContainmentPressure-DECLG(CD=0.6)14.3.2-57Yi0458L:6 LISTOFFIGURES(continued)FigureDescriPtionPage14.3'-14cContainmentPressure-DECLG(CD=0.4)14.3.2"5814'.2-15CorePowerTransient-DECLG(CD=0.4)14.3.2-59,14.3.2"16BreakEnergyReleasedtoContainment-DECLG(CD=0.4)14.3.2-6014.3.2-17ContainmentWallCondensingHeatTransferCoefficient-DECLG(CD=0.4)14.3.2"61Vii0458L:6

14.3PRIMARYSYSTEMPIPERUPTURES14.3.1LossOfReactorCoolantFromSmallRupturedPipesOrFromCracksinLargePipesWhichActuatesEmergencyCoreCoolingSystemIdentificationofCausesandAccidentDescritionAlossofcoolantaccidentisdefinedasaruptureofthereactorcoolantsystempipingorofanylineconnectedtothesystemuptothefirstclosedvalve.Rupturesofsmallcrosssecti'onwillcauselossofthecoolantataratewhichcanbeaccommodatedbythechargingpumpswhichwouldmaintainanoperationalwaterlevelinthepressurizerpermittingtheoperatortoexecuteanorderlyshutdown.Amoderatequantityofcoolantcontainingsuchradioactiveimpuritiesaswouldnormallybepresentinthecoolant,wouldbereleasedtothecohtainment.Themaximumbreaksi.zeforwhichthenormalmakeupsystemcanmaintainthepressurizerlevelisobtainedbycomparing.hecalculatedflowfromthereactorcoolantsystemthroughthepostulatedbreakagainstthechargingpumpmakeupflowatnormalreactorcoolantsystempressurei.e.,2250psia.Amakeupflowratefromonechargingpumpistypicallyadequatetosustainpressurizerpressureat2250psiaforabreakthrougha3/8in.diameterhole.Thisbreakresultsinalossofapproximately17.5lb/sec.Shouldalargerbreakoccur,depressurizationofthereactorcoolantsystemcausesfluidtoflowtothereactorcoolantsystemfromthepressurizerresultinginapressureandleveldecreaseinthepressurizer.Reactortripoccurswhenthepressurizerlowpressuretripsetpointisreached.Theconsequencesoftheaccidentarelimitedintwoways:1.Reactortripandboratedwaterinjectioncomplementvoidformationincausingrapidreductionofnuclearpowertoaresiduallevelcorrespondingtothedelayedfissionandfissionproductdecay.0458L:614.3.1-1 2.Injectionofboratedwaterensuressufficientfloodingofthecoretopreventexcessivecladtemperatures.Beforethebreakoccurs,theplantisinanequilibriumcondition,i.e.,theheatgeneratedinthecoreisbeingremovedviathesecondarysystem.Duringblowdown,heatfromdecay,hotinternalsandthevesselcontinuestobetransferredtothereactorcoolantsystem.Theheattransferbetweenthereactorcoolantsystemandthesecondarysystemmaybeineitherdirectiondependingontherelativetemperatures.Inthecaseofcontinuedheat,additiontothesecondary,systempressureincreasesandsteamdumpmayoccur.Makeuptothesecondarysideisautomaticallyprovidedbytheauxiliaryfeedwaterpumps.Thesafetyinjectionsignalstopsnormalfeedwaterflowbyclosingthemainfeedwaterlineisolationvalvesandinitiatesemergencyfeedwaterflowbystartingauxiliaryfeedwaterpumps.Thesecondaryflowaidsinthereductionofreactorcoolantsystempressure.WhentheRCSdepressurizesto715psia,theaccumulatorsbegintoinjectwaterintothereactorcoolantloops.Thereactorcoolantpumpsareassumedtobetrippedattheinitiationoftheaccidentandeffects'fpumpcoastdownareincludedintheblowdownanalyses.AnalsisofEffectsandConseuencesMethodofAnalysisForsmallbreakslessthan1.0fttheWFLASHdigitalcomputercode2References1,2and3,isemployedtocalculatethetransientdepressurizationofthereactorcoolantsystemaswellastodescribethemassandenthalpyofflowthroughthebreak.Theanalysiswasperformedforanassumedsteamgeneratortubeplugginglevelof12,".andareactorcoolantsystemloop'lowrateof84,000gpm.SmallBreakLOCAAnalsisUsinWFLASHTheWFLASHprogramusedintheanalysisofthesmallbreaklossofcoolantaccidentisanextensionoftheFLASH-4code,Reference3,0458L:614.3.1-2

developedattheWestinghouseBettisAtomicPowerLaboratory.TheWFLASHprogrampermitsadetailedspatialrepresentationofthereactorcoolantsystem.Thereactorcoolantsystemisnodalizedintovolumesinterconnectedbyflowpaths.Boththebrokenloopandtheintactlooparemodeledexplicitlyfortwoloopplants.Thetransientbehaviorofthesystemisdeterminedfromthegoverningconservationequationsofmass,energy,andmomentumappliedthroughoutthesystem.AdetaileddescriptionofWFLASHisgiveninReference1and2.TheuseofWFLASHintheanalysisinvolves,amongotherthings,therepresentationofthereactorcoreasaheatedcontrolvolumewiththeassociatedbubblerisemodeltopermitatransientmixtureheightcalculation.Themulti-nodecapabilityoftheprogramenablesanexplicitanddetailedspatialrepresentationofvarioussystemcomponents.Inparticular,itenablesapropercalculationothebehavioroftheloopsealduringaloss-of-coolanttransient.Safetyinjectionflowratetothereactorcoolantsystemasafunctionofthesystempressureisusedaspartoftheinput.TheSafetyInjection(SI)systemwasassumedtobedeliveringtotheRCS,25secondsafterthegenerationofasafetyinjectionsignal.Fortheseanalyses,theSIdeliveryconsiderspumpedinjectionflowwhichisdepictedinFigures14.3.1-1aand14.3.1-lbasafunctionofRCSpressure.Figure14.3.1-1arepresentsinjectionflowfromoneHHSIpumpbasedonperformancecurvesdegraded5ofromthedesignhead.Figure14.3.1-1brepresentsinjectionflowfromoneLHSIpump.The25seconddelayincludestimerequiredfordieselstartupandloadingofthesafetyinjectionpumpsontotheemergencybuses.AlsominimumSafeguardsEmergencyCoreCoolingSystemcapabilityandoperabilityhasbeenassumedintheseanalyses.I0458L:614.3.1-3 PeakcladtemperatureanalysesareperformedwiththeLOCTAIYcode,References2and4.InputforthecodeisobtainedfromtheWFLASHcodewhichdeterminestheRCSpressure,'uelrodpowerhistory,steamflowpasttheuncoveredpartofthecoreandmixtureheighthistory.Figure14.3.1-2presentstheaxialpowershapeutilizedtoperformthesmallbreakanalysispresentedhere.Thispowershapewaschosenbecauseitprovidesanappropriatedistributionofpowerversuscoreheightandalsolinearpowerismaximizedintheupperregionsofthereactorcore(.10ft.to12ft.).Thispowershapeisskewedtothetopofthecorewiththepeaklinearpoweroccurringatthe10ft.coreelevation.Thelinearpowerforthispowershapeabove10ft.essentiallymatchestheshapeofthegenericoperationF~envelopefornormalplantoperationandhencelinearpowerismaximizedforthe10ft.coreelevationandabove.Thisislimitingforsmallbreakanalysisbecauseoftheuncoveryprocessforsmallbreak.Asthecoreuncovers,thecladdingintheupperelevationofthecoreheatsupandissensitivetothelinearpoweratthatelevation.OThecladdingtemperaturesinthelowerelevationsofthecore,belowthetwophasemixtureheight,remainslow.Thepeakcladtemperatureoccursabove10ft.ResultsofSmallBreakAnalsisThissectionpresentsresultsofthelimitingbreaksizeintermsofhighestpeakcladtemperature.Theworstbreaksize(smallbreak)isa6in.diameterbreak.ThedepressurizationtransientforthisbreakisshowninFigure14.3.1-3.TheextenttowhichthecoreisuncoveredisshowninFigure14.3.1-4.Ouringtheearlierpartofthesmallbreaktransient,theeffectofthebreakflowisnotstrongenoughtoovercometheflowmaintainedbythereactorcoolantpumpsthroughthecoreastheyarecoastingdown0458L614.3.1-4 0

followingreactortrip.Therefore,upwardflowthroughthecoreismaintained.Theresultantheattransfercoolsthefuelrodandcladto'Iverynearthecoolanttemperaturesaslongasthecoreremainscoveredbyatwophasemixture.Themaximumhotspotcladtemperaturecalculatedduringthetransientis1092'FincludingtheeffectsoffueldensificationasdescribedinReference5.ThepeakcladtemperaturetransientisshowninFigure14.3.1-5fortheworstbreaksize,i.e.,thebreakwiththehighestpeakcladtemperature.ThesteamflowratefortheworstbreakisshownonFigure14.3.1-6.Whenthemixtureleveldropsbelowthetopofthecore,thesteamflowcomputedinWFLASHprovidescoolingtotheupperportionofihecore.TherodfilmcoefficientsforthisphaseofthetransientaregiveninFigure14.3.1-7.ThehotspotfluidtemperaturefortheworstbreakisshowninFigure14.3.1-8.Thereactorscramtimeisequaltothereactortripsignaltimeplus4.4secondsforsignaltransmissionandrodinsertion.Duringthisperiod,thereactorisconservativelyassumedtooperateatratedpower.AdditionalBreakSizesAdditionalbreaksizeswereanalyzed.Figures14.3.1-9aand14.3.1-9bpresenttheRCSpressuretransientforthe4and8in.breaksrespectivelyandFigures14.3.1-10aand14.3.1-10bpresentthevolumehistory(mixtureheight)plotsforthesebreaks.Thepeakcladtemperaturesforthesecasesarelessthan-thepeakcladtemperatureofthe6in.break.ThepeakcladtemperaturesforthesecasesaregiveninFigures14.3.1-llaand14.3.1-11b.ConclusionsAnalysespresentedinthissectionshowthatthehighheadandlowheadportionsoftheemergencycorecoolingsystem,togetherwith0458L:614.3.1-5 accumulators,providesufficientcorefloodingtokeepthecalculatedpeakcladtemperaturesbelowrequiredlimitsof10CFR50.46.Hence,adequateprotectionisaffordedbytheemergencycorecoolingsytemintheeventofasmallbreaklossofcoolantaccident.Table14.3.1-1presentstheresultsoftheseanalyses.0458L:614.3.1-6 REFERENCES-Section14.3.11.Esposito,V.J.,Kesavan,D.,Maul,B.A.,"WFLASH-AFORTRANIVComputerProgramforSimulationofTransientsinaMulti-LoopPWR",WCAP-8261,Rev.1,July,'974.2.Skwarek,R.J.,Johnson,W.J.,andMeyer,P.E.,"WestinghouseEmergencyCoreCoolingSystemSmallBreakOctober1975Model,"WCAP-8970-P-A(Proprietary)andWCAP-8971-A(Non-Proprietary)January1979.3.Porsching,T.A.,Murphy,J.H.,Redfield,J.A.,andDavis,V.C.,"FLASH-4:AFullyImplicitFORTRAN-IVProgramfortheDigitalSimulationofTransientsinaReactorPlant",WAPD-TM-84;BettisAtomicPowerLaboratory,March,1969.4.Bordelon,F.M.,etal.,"LOCTA-IVProgram:Loss-of-CoolantTransientAnalysis",WCAP-8301(ProprietaryVersion),WCAP-8305(Non-ProprietaryVersion),June1974.5.Hellman,J.M.,"FuelDensificationExperimentalResults'andModelforReactorAppl.ication",WCAP-8219,gctober,1973.0458L:614.3.1-7 TABLE14.3.1"1SMALLBREAKTIMESEQUENCEOFEVENTSEvent'4in.6in.8in.Start0.00.00.0ReactorTripSignal(Sec.)12.510.09.5TopofCoreUncovered(Sec.)165.74.69.AccumulatorInjectionBegins(Sec.)323.138.75.PCTOccurs(Sec.)333.7121.492.0TopofCoreCovered(Sec.)374.168.101.0458L:614.3.1-8 TABLE14.3.1-2SMALLBREAKANALYSISINPUT.ANDRESULTSResults4in.6in.8in.PeakCladTemp.'F9761092758PeakCladLocationFt.11.75,10.7510.75LocalZr/H20Rxn(max)X0.06780.06890.0675LocalZr/H20LocationFt.11.7510,.7510.75Total'r/H20Rxn%%d<0.3<0.3<0~3HotRodBurstTimesecnoburstnoburst.noburstHotRodBurstLocationFt.noburstnoburstnoburstCa1cula.ionCorePowerMMt1004of1520PeakLinearPowerkw/ft102~ofSeeFigure14.3.1-2PeakingFactor(AtLicenseRating)Accumulatorh'aterVolumeFt.3SeeFigure'4.3.1-211000458L:614.3.1-9

16001400FIGURE14.3.1-1aHIGHHEADSAFETYINJECTIONFLOWRATEOnePunpinOperation1200-1000800600400200102030S'.I.FLOW(lb/sec)4050600458L:614.3.1-.10 160140FIGURE14.3.1-1bLOWHEADSAFETYINJECTIONFLOWRATEOnePumpinOperation12010080604020IL0204060.80100120140160180200220S.I.FLOW(1b/sec)0458L:614.3.1-11 14FIGURE14.3.1-2HOTRODAXIALPOWERSHAPE1210U6C)CD02COREHEIGHT(Ft.)0458L:614.3.1-12 FIGURE14.3.1-3DEPRESSURIZATION~iNSIENT(6INCH)O'Oool00'OOL00'005ICCIoo'oos~00'OowIvhXa.Vl4JCC~/1IClkIL00'OOK00'OOZ00'OOl0'0OoCICIoYtSII38flSS3tl4S)ICI0458L:614.3.1-13 P

FIGURE14:3.1-4COREMIXTUREHEIGHT(6INCH)OOOOt00'00800'ool00'008IlalIIICClsJ~illoo'oos*I00'ooeZ4laIXaelab'X~eJlalCL'O~C00'00800'OOZ00'ool0'00458L:6CI<lglIH'Jl3H380314.3.1-14C7CI

FIGVRE14.3.1-5PEAKCLADTEHPERATVRETRANSIENT(6INCH)0'oool00'0060000800'OOCClC~I00009CIIVlgCCggEQIoOELCOOZELX4JZCsatCCL"oooos<00'00100'OOE00'OOZ00'Oot0'0oCl8tQ<3$33ei30)CI008!OH'4H3L'OATOT1)CIoCICI0458L:614.3.1-15 FIGURE14;3.1-6STEAMFLOWRATE0'000100'OotIIACCIIw00'os<I~JuVlVlZsoXU4a00'Oot00'00C00'00200'0010'08888)35/illAolgHr315CI8888888S.0458L:614.3.1-16

EDVl00I~~Ch600.00$00.00F00.00~300.00g200.00RGE6INCIISNAtlBRCAKTRANSIENTHEATTRARS.COEF.NOTASSTBURSTe10.00FTllP(AX~I0.75FTT~l60.000~50.000i0.00030.000X'0.0006.0000$.0000~.00003.00002.0000XlEDC3mOmnImI.OOOOooCICICICICICICICITIH([SEC)DooMICIDooClCIoCI

.T000.0RGE0IREHSHALLBREAKTRAllSIEllTFLUIDTEMPERATUREBURST~l0.00FTl)PEAK,IO.TSFll~l2500.02000.0IIS00.0oI000.0ClCTlX7mCJCrJImm500.000.0ClCIClCloAlCImClClCloInTIHElSEEIClClooEOClCloo C7Vl00I~~C7l8000.0ZS00.0RGfIIkUFLASHSHALLSRfAKTRAlISIfNIRCSPRfSSURf(PSIACL%00.0~CEA~CIS00.0-A7IlKlfoalGDIlOI000.00.0ClCIClClClAjoOoClooVICloCl CJlCOI~~2800.02500.0AfE8IHVfLEASHSHALLBREA'RAHSIEHJ.RESIRE(CUREIPSIX2000.0CCVlMO:CLI500.0I000.0IC)C7mmt/lIjl~-emQIIIIm500.00n0.0ooooooP%oooTIHE(SEC)oaooEOooooo

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EDVlCOI~~CJlIA.QQQI8.500RGE8IHVELASHSHALLBREAKTRANSIEIITEQREHEIGHTIFTIGOItOtOIlal0.000Ku75QQQ5.0000Tl>CAm~~4lIOoocr2.50000.0OOOCIOOOoAlOOOOOOTIHE(SEE)OOOOO07OO~DEtlOOO

%00.0RGfIIIICH'SHALLBRfAaTRAIIS1fIITCLAOAVGTfHP~HOTR00BURST~'10~00TTI)PfAR~11~75TTI+IR.SOO.Oo2000.0oZ1500.00CI1000.00.0ooooooooomoooT1HfIS'fCIo

C)CJlCQI~~Ch3000.0RCE8INCHSHALLBREAKTRANSIENTCLAOAVG.TEHP.HOTROOBOASTS10.00ETI)PEAK~I0.15FTI~Iw+QQ.Qwcl2000.0ZI500.0mClmAlmt/0mI000.0500.000.0ClClClClClCDClAl8ClClClnTIHEISEC)CIClClClCl 14.3.2MajorReactorCoolantSystemPipeRuptures(LossofCoolantAccident)Theanalysisspecifiedby10CFR50.46,"AcceptanceCriteriafor,EmergencyCoreCoolingSystemsforLightVaterPowerReactors",Reference1,ispresentedinthissection.TheresultsofthelossofcoolantaccidentanalysisareshowninTable14.3.2-2andshowcompliancewiththeAcceptanceCriteria.TheanalyticaltechniquesusedareincompliancewithAppendixKof10CFR50,andaredescribedinlistedreferences.Theresultsforthesmallbreakloss-of-coolantacciden.arepresentedinSection14.3.1andareinconformancewith10CFR50.46andAppendixKof10CFR50.Shouldamajorbreakoccur,depressurizationofthereactorcoolantsystemresultsinapressuredecreaseinthepressurizer.Reactortripsignaloccurswhenthepressurizerlowpressuretripsetpointisreached.Asafetyinjectionsystemsignalisactuatedwhentheappropriatesetpointisreached.Thesecountermeasureswilllimittheconsequencesoftheaccidentintwoways:1.Reactortripandboratedwaterinjectioncomplementvoidformationincausingrapidreductionofpower.oaresiduallevelcorrespondingtofissionproductdecayheat.12.Injectionofboratedwaterprovidesheattransferfromthecoreandpreventsexcessivecladtemperatures.1Atthebeginningoftheblowdownphase,theentirereactorcoolantsystemcontainssubcooledliquidwhichtransfersheafromthecorebyforcedconvectionwithsomefullydevelopednucleateboiling.Afterthebreakdevelops,thetimetodeparturefromnucleateboilingiscalculated,consistentwithAppendixKof10CFR50.Thereafter,the0458L:6l4.3.2-l coreheattransferisunstable,withbothnucleateboilingandfilmboilingoccurring.Asthecorebecomesuncovered,bothturbulentandlaminarforcedconvectionandradiationareconsideredascoreheattransfermechanisms.Whenthereactorcoolantsystempressurefallsbelow715psiatheaccumulatorsbegintoinjectboratedwater.Theconservativeassumptionismadethataccumulatorwaterinjectedbypassesthecoreandgoesoutthroughthebreakuntiltheterminationofbypass.ThisconservatismisagainconsistentwithAppendixKof10CFR50.CorePowerTransientDurinBlowdownThecorepower.ransientduringblowdownforlargebreaksisevaluatedusingtheSATAN-VIcomputercode.ThiscodeisdiscussedindetailinWCAP-8306,Reference3.ThermalAnalsisPerformanceCriteriaforEmerencCoreCoolinSstemThereactorisdesignedtowithstandthermaleffectscausedbyalossofcoolantaccidentincludingthedoubleendedseveranceofthelargestreactorcoolingsystemcoldlegpipe.Thereactorcoreandinternalstogetherwiththeemergencycorecoolingsytemaredesignedsothatthereactorcanbesafelyshutdownandtheessentialheattransfergeometryofthecorepreservedfollowingtheaccident.Theemergencycorecoolingsystem,evenwhenoperatingduringheinjectionmodewiththemostseveresinglefailure,isdesignedtomeettheAcceptanceCriteria.0458L:614.3.2-2

MethodofThermalAnalsisThedescrsptsonofthevariousaspectsoftheLOCAanalysisisgiveninthelistedreferences.Thisdocumentdescribesthemajorphenomenamodeled,theinterfacesamongthecomputercodesandfeaturesofthecodeswhichmaintaincompliancewiththeAcceptanceCriteria.TheSATAN-VI,WREFLOOD,andLOCTA-IVcodesusedinthisanalysisaredescri.bedindetailinWCAP-8306,Reference3,WCAP-8171,Reference5andWCAP-8305,Reference4,respectively.ThecontainmentparametersusedinthecontainmentanalysiscodetodeterminetheECCSbackpressurearepresentedinTable14.3.2-3.Thecontainmentpressureanalysiscode(COCO)isde'scribedinWCAP-8326,Reference6.ThelargebreakanalysiswasperformedwiththeNRCApproved1981VersionoftheEvaluationModel,Reference24,whichincludesmodificationsdelineatedinWCAP-9220-P-AandWCAP-9221-A(1981),andcomplieswithAppendixKof10CFR50.46.Theanalysiswasperformedforanassumedsteamgeneratortubeplugginglevelof12andareactorcoolantsystemloopflowrateof84,000gpm.ResultsTable14.3.2-2presentsthepeakcladtemperaturesandhotspotmetalreactionforalargebreakoverarangeofdischargecoefficientsorbreaksizes.Thisrangeofdischargecoefficientswasdeterminedtoincludethelimitingcaseofpeakcladtemperaturefromthesensitivitystudies.Theanalysisofthelossofcoolantaccidentisperformedat102,.ofratedcorepower.Thepeaklinearpower,andcorepowerusedintheanalysesaregiveninTable14.3.2-2.TheequivalentcoreparameteratthelicenseapplicationpowerlevelarealsoshowninTable14.3.2-2.Sincethereismarginbetweenthevalueofthe-peaklinearpowerdensityusedinthisanalysisandthevalueexpectedinoperation,alowpeakcladtemperaturewouldbeobtainedbyusingthepeaklinearpowerdensityexpectedduringoperation.0458L:614.3.2-3 Fortheresultsdiscussedbelow,thehotspotisdefinedtobethelocationofmaximumpeakcladtemperature.ThislocationisgiveninTable14.3.2-2foreachdischargecoefficientorbreaksizeanalyzed.Tables14.3.2-4and14.3.2-5presentrefloodmassandenergyreleasestothecontainmentandthe'rokenloopaccumulatormassandenergyreleasetothecontainment,respectively.Figures14.3.2-1through14.3.2-16presentthetransientsfortheprincipalparametersforthedischargecoefficientsanalyzed.Thefollowingitemsarenoted:Figures14.3.2-1aguality,massvelocity,andcladheattransfercoef-through14.3.2-3cficientforthehotspotandburstlocations.Figures14'.2-4athrough14.3.2-6cCorepressure,breakflow,andcorepressuredrop.Thebreakflowisthesumoftheflowratesfrombothendsoftheguillotinebreak.Thecorepressuredropistakenasthepressurejustbeforethecoreinlettothepressurejustbeyondthecoreoutlet.Figures14.3.2-7aCladtemperature,fluidtemperature,andcoreflow.through14.3.2-9cThecladandfluidtemperaturesareforthehotspotandburstlocations.Figures14.3.2-10aRefloodTransient-CoreInletVelocitythrough14.3.2-10cIFigures14.3.2"11aRefloodTransient-CoreandDowncomerWaterLevelsthrough14.3.2.11cFigures14.3.2-12aEmergencycorecoolingsystemflowrates,forboththrough14.3.3-13aaccumulatorandpumpedsafetyinjection.045SL6l4.3.2-4 Figures14.3.2-14aContainmentpressure.through14.3.2"14cFigure14.3.2-15CorepowerFigures14.3.2-16Breakenergyreleaseduringblowdownandthecon-and14.3.'2-17tainmentwallcondensingheattransfercoefficientfortheworstbreak.Thecladtemperatureanalysisisbasedonatotalpeakingfactorof2.32.Thehotspotmetal-waterreactionreachedis2.1%whichiswellbelowtheembrittlementlimitof17~asrequiredby10CFR50.46.Inaddition,thetotalcoremetal-waterreactionislessthan0.3~forallbreaksascomparedwiththe1Xcriterionof10CFR50.46.TheresultsofECCSevaluationsandsensitivitystudiesarereportedinReferences2,7,8,9,26,12,13,16,18,20and24.Theseresultsarereportedonagenericandplantspecificbasis.ConclusionsForbreaksuptoandincludingthedoubleendedseveranceofareactorcoolantpipe,theemergencycorecoolingsystemwillmeettheacceptancecriteriaaspresentedin10CFR50.46.Thatis:1.Thecalculatedpeakfuelelementcladtemperatureisbelowtherequirementof2200~F.)2.Theamountoffuelelementcladdingthatreactschemicallywithwaterorsteamdoesnotexceed1percentofthetotalamountofZircaloyinthereactor.0458L:6l4;3.2-5 i3.Thecladtemperaturetransientisterminatedatatimewhenthecoregeometryisstillamenabletocooling.Thelocalizedcladdingoxidationlimitof17percentisnotexceededduringorafterquenching.4.Thecoreremainsamenabletocoolingduringandafterthebreak.5.Thecoretemperatureisreducedanddecayheatisremovedforanextendedperiodoftimeasrequiredbythelong-livedradioactivityremaining.inthecore.ThetimesequenceofeventsforallbreaksanalyzedisshowninTable14.3.2-1.BasedontheeffectofupperplenuminjectionforWestinghousedesigned2loopplants,a21Fincreaseinpeakcladtemperatureresultsfromassuming14xl4OFAfuelforR.E.GinnaUnit1.ThemethodologyemployedtodevelopthispenaltywasidenticaltothatperformedforpreviousLOCAanalysesperformedforthe.plant,Reference19,and27.UtilizingthepresentWestinghouseECCSevaluationmodels,References14,15,16and24,toanalyzeapostulatedLOCAinR.E.GinnaUnit1,resultsinafinalpeakcladtemperatureof1854FincludingtheUPIpenalty.ItcanbeseenfromtheresultscontainedhereinthatthisECCSanalysisforR.E.Ginnaremainsincompliancewith10CFR50.46.0458L:614.3.2.-6 REFERENCES-Section14.3.21."AcceptanceCriteriaforEmergencyCoreCoolingSystemsforLightWaterCooledNuclearPowerReactors:10CFR50.46andAppendixKof10CFR50.46,"FederalRegister,Volume39,Number3,January4,1974.2.Bordelon,F.M.,Massie,H.W.,andZordan,T.A.,"WestinghouseECCSEvaluationModel-Summary,"WCAP-8339,July1974.3.Bordelon,F.M.,etal.,"SATAN-VIProgram:ComprehensiveSpace-TimeDependentAnalysisofLoss-of-Coolant",WCAP-8302(ProprietaryVersion),WCAP-8306(Non-ProprietaryVersion),June1974.4.Bordelon,F.M.,etal.,"LOCTA-IVProgram:Loss-of-CoolantTransientAnalysis",WCAP-8301(ProprietaryVersion),WCAP-8305(Non-ProprietaryVersion),June1974.5.Kelly,R.D.,etal.,"CalculationalModelforCoreRefloodingafteraLoss-of-CoolantAccident(WREFLOODCode)".WCAP-8170(ProprietaryVersion),WCAP-8171(Non-ProprietaryVersion),June1974.6.Bordelon,F.M.,andMurphy,E.T.,"ContainmentPressureAnalysisCode(COCO)",WCAP-8327(ProprietaryVersion),WCAP-8326(Non-ProprietaryVersion),June1974.7.Bordelon,F.M.,etal.,"TheWestinghouseECCSEvaluationModel:SupplementaryInformation",WCAP-8471(ProprietaryVersion),WCAP-8472(Non-ProprietaryVersion),January1975.8.Salvatori,R.,"WestinghouseECCS-PlantSensitivityStudies",WCAP-8340(ProprietaryVersion),WCAP-8356(Non-proprietaryVersion),July1974.0458L:614.3.2-7

REFERENCES-Section14.3.2(cont)9.Delsignore,T.,etal.,"WestinghouseECCSTwo-LoopSensitivityStudies(14x14)"WCAP-8854(Non-ProprietaryVersion),September1976.10."WestinghouseECCSEvaluationModel,October,1975Versions",WCAP-8622(ProprietaryVersion),WCAP-8623(Non-ProprietaryVersion),November1975.11.LetterfromC.EicheldingerofWestinghouseElectricCorporationtoD.B.VassalooftheNuclearRegulatoryCommission,letternumberNS-CE-924,January23,1976.12.Kelly,R.D.,Thompson,C.M.,etal.,"WestinghouseEmergencyCoreCoolingSystemEvaluationModelforAnalyzingLargeLOCAsDuringOperationwithOneLoopoutofServiceforPlantswithoutLoopIsolationValves",WCAP-9166,February,1978.13.Eicheldinger,C.,"WestinghouseECCSEvaluationModel,February1978Version",WCAP-9220(ProprietaryVersion),WCAP-9221(Non-ProprietaryVersion),February,1978.14.LetterfromT.M.AndersonofWestinghouseElectricCorporationtoJohnStolzoftheNuclearRegulatoryCommission,letternumberNS-TMA-8130,June1978.15.LetterfromT.M.AndersonofWestinghouseElectricCorporationtoJohnStolzoftheNuclearRegulatoryCommission,letternumberNS-TMA-1834,June20,1978.16."SafetyEvaluationReportonECCSEvaluationModelforWestinghouseTwo-LoopPlants",November,1977.0458L:6l4.3,2-8 REFERENCES-Section14.3.2(cont)17.LetterfromS.BursteinofWisconsinElectricPowerCo.toE.G.CasisoftheNuclearRegulatoryCommission,January17,1978.18.LetterfromR.L.KellyofWestinghouseElectricCorporationtoT.R.WilsonofWisconsinElectricPowerCo.,letternumberWEP-78-2,February24,1978.19."NRCQuestionsRegardingthe1/16/78SubmittalbyWestinghouseDesignedTwo-LoopPlantOperators",February1,1978.20.RefertoReference18.21'SafetyEvaluationReportonInterimECCSEvaluationmodelforWestinghouseTwo-LoopPlants",March1978.22.LetterfromS.BursteinofWisconsinElectricPowerCo.toE.G.CaseoftheNuclearRegulatoryCommission,March16,1978.23.LetterfromS.BursteinofWisconsinElectricPowerCo.toE.G.CaseoftheNuclearRegulatoryCommission,April6,1978.24.Eicheldinger,C.,"WestinghouseECCSEvaluationModel,1981Version",WCAP-9220-P-A(ProprietaryVersion)andWCAP-9221-A(Non-Proprietary),Revision1,1981.25.Johnson,W.J.andThompson,C.M,"WestinghouseEmergencyCoreCoolingSystemEvaluationModel-ModifiedOctober1975Version",WCAP-9168(Proprietary)andWCAP-9169(Non-Proprietary),1977.26."WestinghouseECCSEvaluationModelSensitivityStudies",WCAP-8341(Proprietary)andWCAP-8342(Non-Proprietary),1974.27.LetterfromR.A.Wiesemann,(Westinghouse)toD.Eisenhut(NRC),December11,1979.0458L:6l4.3.2-9

0TABLE14.3.2-1LARGEBREAKTINESEQUENCEOFEVENTSDECLG(CD08)DECLGCD0'6DECLGCDSecSTARTReactorTripSignalS.I.SignalAcc.InjectionEndofBlowdownPvmpInjectionBottomofCoreRecoveryAcc.Empty0.00.5810.474.5916.84825.4731.95851.3550.00.5890.545.7814.41625.5432.99053.8680.00.6020.658.2423.45425.6538.78556.100458L:614.3.2-10 TABLE14.3.2-2LARGEBREAKANALYSISINPUTANDRESULTSResultsDECLG(CD0'8DECLGCD0'6DECLG(CD=0.4)PeakCladTempFPeakCladTemp.LocationFt.Local.Zr/H20Rxn(max)LocalZr/H20LocationFt.TotalZr/H20RxnHotRodBurstTimesecHotRodBurstLocationFt~17517.51.57.5<0.364.86.7517307.51.47'<0.365.87.01833"7.52.17.5<0.353.06.0CalculationCorePowerMWt102~ofOPeakLinearPowerkw/ft102ofPeakingFactor(AtDesignRating)AccumulatorWaterVolume(CubicFootperTank)AccumulatorPressure(psia)NumberofSafetyInjectionPumpsOperatingSteamGeneratorTubesPlugged152013.4852.3211007152Fuelregion+cycleanalyzedCycleRegionR.E.GinnaR.E.GinnatoSpecifyWestinghouseOFARegion"A21FPCTpenaltymustbeaddedtotheanalysisvaluetoaccountforUPIinjectionpenalty.0458L:614.3,2-1,l TABLE14.3.2-3LARGEBREAKCONTAINMENTDATA(DRYCONTAINMENT)NetFreeVolume1.066x10ftInitialConditionsPressureTemperatureRWSTTemperatureServiceWaterTemperatureOutsideTemperature14.7psia90oF60~F35oF10oFSpraySystemNumberofPumpsOperatingRunoutFlowRateActuationTime21800gpmeach10secsSafeguardsFanCoolersNumberofFanCoolersOperatingFastestPostAccidentInitiationofFanCoolers30secs0458L:6l4.3.2-l2

TABLE14.3.2-3(Cont.)STRUCTURALHEATSINKDATADescritiveSurfaceAreaExposedtoContainmentAtmoshereLayerThickness~Laerinsulatedportionofdomeandcontainmentwall361811"1/4"3/8ll2I6llInsulationSteelConcreteuninsulatedportionofdome12474ft.23/8"2I6llSteelConcretebasementfloor7955ft.2'/8"2IConcrete'teelConcretewallsofsumpinbasementfloor2342ft.5I3/8"3I6llConcreteSteelConcretefloorofsump297ft.2I3/8"2IConcreteSteelConcreteinsideofrefuelingcavity5200ft.1/4'I2I6llSteelConcretebottomofrefuelingcavity1200ft.1/4ll2I6llSteelConcreteareaonoutsideofrefueling6900ft.2cavitywalls2I6llConcreteareainsideofloopandsteamgeneratorcompartment14900ft.2I6llConcretefloorareaintermediatelevel6170ft.Concreteoperatingfloor1-1/2"thickI"beam6540ft.3151ft.2'-1/2"ConcreteSteel0458L:614.3.2-13

DescritiveSurfaceTABLE14.3.2-3(Cont.)STRUCTURALHEATSINKDATAAreaExposedtoContainmentAtmoshereLayerThickness~Laer1"thickI-beam1/2"thickI-beamcylindricalsupportsforS.G.8MCP's5016ft.8138ft.430ft.Steel1/2IISteel1/2"'teelplantcranerectangularsupportcolumns5756ft.3/4"Steelbeamsusedforcranestructure6023ft,Steelstructureonoperatingfloor2622ft.2'oncretefromFSAR:grating,stairsmisc.steels7000ft.0104Steel0458L:6')4.3.2-14 0

TABLE14.3.2-4REFLOODMASSANDENERGYRELEASETimesecMassFlowlb/secEnerFlowBTU/sec38.785'9.040.045.059.069.079.089.099.0119.0139.0189.0399.00~00.008310.0089431.42692.496140.052173.728187.574193.280198.273202.387211.909240.9900.010.66011.47940535.91106286.56118474.87125391.45126392.58125252.45121543'9117805.11109040.9692584.280458L:614.3.2-l5 TABLE14.3.2-5BROKENLOOPACCUMULATORMASSANDENERGYRELEASETimesecMassFlowlb/secEnerFlowBTU/sec1.0102.0103.0104.0105.0106'107.0108.0109.01010.01011.01012.01013.01014F01015.01016.01017.01018.01019.01020.0102549.2622435.2932336.0902248.9812170.6862099.7242035.2371976.3881922.5601873.2131827.7661785.5491746.2011709.4241675.0791643'181613.4961585.6601559.4141534.659152779.845145949.518140004.203134783.662130091.404125838.537121973.761118446.914115220.959112263.515109539.815107009.731104651.550102447.507100389.15598479.72796698.41995030.18293457.24991973.6510458L:614.3.2-l6 I.1000I.ZSOORCKIaXIaOFAtO~0.0350PSISIR/C/L~ISKRIKSS.C.IZPKRCKNFIUQKPLVCCINCIIHOOKLt~310FOOVALITYOFFLUIOSVRSIeC15FTIlPKAR~1~50Fll~I~zI.00000.15000.5000O.ZSOO0.0CIC7aCSClCIC700gOOOOOR5QS~~~~~~00OOOO~88im83P.ruaenoranIIHKlSE'tl~fg~gg~pFigureill.3.2-1aFluidQuality-DECLG(CD=0.8)

I.loooI.F500ACEI~XIiOFACO~0~C350PSI5/1/C/L~1SESIESS.C.ItPEICESTruSKPLUCCI~CSlMODEL2.3ZOfoouALITYoffLUID~USST~l,ooFTIIPEAK~I50FTt~14JLtaWI.OOOO07500Io~0-5000O.ZXN0.0IINIwmlmm000OD~mmmIINNII5I5!fsSP.8Q8TIHE(SEC)88888888~I~PI8$NFigure14.3.2-1bFluidQuality-DECLG(CD=0.6)

I.F000I.ZVOICEI1XIlOFACOO.a350PSISIR/CIL1iSERIESS.C.IZPERCENTTVBEPLVCCINCOIHOOELR.jtFOOVALITTOFFLVIO1VRST~C~00FTlIPEANt7+$0FTI~lRWEJ4C!.00003O.NOI0o5000O.85000.0k.mIN)kmooooooooII'kmmmmP.I555555P.SSod@88888888~8888888TIHE(SEEIFi"ure1l.3.2-1cFluid(}ua]ity-DECLG(CD=0.>I) 500.00~00.00RCEIIXIIOCACDO.ll50PSIS/R/C/EiISERIESS.C.IZPERCERTTUQEPLUCCINCIIHODEI.Z.lZOFOHASSVELOCIIYeuRSr.C.)5rTIIPEAr.7.50FII~I100.000000000800000~~~~~~~0000~z883mm(MIIp~8IZIRCONIIMEISECIFigure1II.3.2-2at'lassVelocity-DECLG(CD=0.8)

RCEIIXI4OFACO~0.C3SOPSISIRIC/LI~SERIESS.C,IZtERCENTTUSEPLUCCIllCOIHOOELtolt0FOHASSYELOCITT~URST1QQFTIlPEAK~7.$0FTl~l3mICSIIIm0O00OOOOINIIImmmmm.TIHElSECl88888888-IIII55HNFigure14.3.2-2bHassVelocity-DECLG(CD=0.6)

RCEIAXIIOFACO>0.4350PSIS/R/C/L~lSERIESS.C.I2PERCENTTUBEPLUGCINCBlHOOEL2.32FOHASSVELOCITYBURStC.OOFTIIPEAKT~SOFTI~ICIIIIIPmmmIIIMNNNI.m<NP'R~SSRRBTIHE(SEC)Figure14.3.2-2ct1assVelocity-DECLG(CD=0.4)

a600.00500.00100.00300.00Z00.00RGEliXliOFACO*0.B350PSIS/R/C/I.11SERIESS.G.IZPERCERTTUBEPLUGGIHGBlHOOEL2.320FOHEATTRANS.COEFFICIENT.BURST~Cl5FTIIPEAKED3.50FIl~I10.00030.00020.0006.00005.00001.00003.00002.0000I.ooooCI88TIHE(SEC)Fi"ure14.3.2-3aHeatTransferCoefficient-DECLG(CD=0.0)

IlltII600.00500.00000.00zX0,00%0.00RCE11XtlOFAEoio.C350PSlS/R/E/Ll~SERlESS.C.tZPERCERTTUBEPLUCCIRCelHOOELCe)toFOHEATTRANS~COEFFtctERTBuRSt.T.OOFTT)PEAR~F~SoFTt~>40.000g,QQQx%.000IKC.00005.00001.0000).00008.0000l.0000ClCICI88TlHElSECI88IVCICIFigure14.3.2-3bfleatTransferCoefficient-DECLG(CD=0.6) 0 IIIC00.00500.00100.00300.00200.00ROEl~XliOFACO~0.i350tSlS/RIC/LiiSERlESSC.l2PERCENTTUSEPLUGClkCIlKOOEL232FONEATTRANS.COEFFlClENTBURST.C.OOFTt)tEAKT.50FTE~I=.I':lli0.00030.00020.000IMi.00003.00002.0000l.000088TlHE(SEC)eicure14.3.2-3clleatTransferCoefficient-DECLG(CD=0.4) t500.0RCEOEAIt+T-l'I50PSI.CO~0.II'SllCONFICURATIONCONTROLECCSHOOELSCO+OolOECLCFRY"IltPRESSURECORE.SOTTOHlITOP~l~l&F000.0IS00.0lalILI000.0.0.0C)TIHEISEC}Figure14.3.2-4aCorePressure-DECLG(CD=0.0)

t500.0RCEOFAIt+T.P.350PSICO%0.CItlICONFICURATIOIICORTROLECC5NOOEL'5CO~O+COECLCPXY~laltPRE'SSURECOREIQTTOKIITOP~I~It000.0ISOO0MI000.00.0C7CITIKEISEC)Figure1II.3.2-4bCorePressure-DECLG(CD=0.6)

Z500.0RCEOFAIZ+E.P.350PSICONO~1l90IKOllflCURAIIOllCO)IIROLEKCSHOOELSCO*0.IOECLGFRV*I.IZPRESSURECOREOOITOH))IOP~I~)Z000.0I500.0I000.00.0oCPCl0'IIHEISEC)Figurel~.3.2-IIcCorePressure-DECLG(CD=O.II)

I.OOEN5ACEOfh,lt+T.t.3SOFSICO<0.0ISllCOHCICUAATIOllCOIITAQLECCSHOOELSCO44OECLCFRYIItPAEArFLOVvl.OOE+OlC.OOENNleCCED1.00EMt.OOERs0.0TIIIE(SECIFigure1II.3.2-5aBreakFlowBate-DECLG(CD.=-0.8) l I.OOEK5hCEOFAIZ+T.t.HOPSICORO.CISOICORI'ICUhATIONCONThOLfCC$HOOELSCDIO.COECLPTXYII~IZ~hfAXfLOUEIO.OOE+01C.OOEttNKWOhi.OOEK)it.OOENH0.0C7~4~nC7TIHEISECIFigure14.3.2-5bBreakFlewRate-DECLG(CD=0.6) 5.00C<iRC(OFA12+1.P.350P51CO*0.i1981COHPICURAflOkCOHlROLECC'SHOOCLSCO*0.4OECLGFxY=l.12SR(AKFLOV3.00EK)i3aC72.00C~0i1.00CRa0.0oOCIT1xC1SCC1C7VlFigureill.3.2-5cBreakFlowRate-DECLG=(CD=0.4) 70.000RCEOFAlt+T.t.350PS(CO~0I1'0~ICONFlCURATIONCORTROLECCSHOOELSCOiO.IOECLCFXY>laitCOREtR.OROP~t5.0000.0RS.OOO-10.000aTi~E~SECiF'igure14.3.2-6aCorePressureDrop-DECLG(CD=08) lo.nRCEOFAIt+-T.P.350PSICORO.CISlICOIIFICURATIOIICONTROLECCSHODELSCO+0COECLCf<>+I~ItCOREPR.DROP4.~t5.000CI~COWClEl0.0<S.000-70.000ClC7oTIHEISECIFigure14.3.2-6bCorePressureDrop-DECLG(CD=0.6)

10.000ACEOfAl2+l.P.350PSlCO*0.i198ICORFICURAflOIICORJROLECCSHOOEESCO*0.IOECLGFXY*l~lZCOBEPR.OAOPCLi5.000Ch0.0-50.000-10.000CIOllHEISEC)C7vsFigureill.3.2-6cCorePressureDrop-DECLG(CD=0.>l)

Z500.0RGEIIXIIOFACO~0.0350PSI5/R/C/Ll1SERIESS.G.IZPERCENTTUSEPLUGGINGOlHOOELZ~IZOFOCLAOAVG.TEHP.HOTROOQURSTC.15FTlI.PEAR750Fll~1Vl~Z000.0ClISN.OXCLZIt7o1000.00.0CICI88TIHE(SEC)Figure1II.3.2-7aPeal<CladTemperature-DECLG(CD=0.8)

2500.0RCEIIX11OFACD~0.C350PSIS/R/C/L1~SERIKSS.C.IZPERCENT-TUSKPLUCCINC~IHODELi~Tt0FOCLADAYC.TEHP,NOTRODBURST7.00FTIIPEAR~I~50FTl~I~%00.0ClC3CgI500.0XE.XlJoIOOO.OlJ0.0C)C)88TIHEtSECIFigure14.3.2-7bPeal<CladTemperature-DECLG(CD=0.6)

RCKTlXTiOT'ACOIOI350.PSISIRICILSERllSS.C.12PERCENTTUSEPLUCClNCITHOOELl3ZPOCLAOAVC~TKHP.NOTROOQURSTC~00Fll1PfAK~T$0Tl~l~2000.0oCICC1500.0XE.XIN~Jo1000.0~N500.000.0o88TIHE(SECIFigure1ll.3.2-7cPeal<CladTenperature-DECLG(CD=0.>l)

Z000.0a1750.0RCEIiXIiOfACD~0.I350tSIS/R/C/L~iSERIES5C.IZtERCENTTUbE.tLUCCINCblHODELZ~3ZOf0flUIDTEHPERATUREbURST~C~7$fTI1tEAK~7,$0fTl~11500.0IZ50.0I1000.0CLxI750.00~a0.0CIC788'TIHElSEC)8Figure1II.3.2-8aFluidTemperature-DECLG(CD=0.8)

F000.0IT50.0ACEIlXI1OFACO~0,C350PSIS/R/C/L41SERIESS.C.ItPEREERTTUSEPLUCCINCIIHOOELt3toFOFLUIOTEHPEAATUREOURST~7~00FTI)PEAK~1.50FTI~I~Col500.0IZ50.0~g1000.04xCI~F50.00t50.000.0C)88TIHEISECI8Figure14.3.2-8bFluidTemperature-DECLG(CD=0.6) 0 2000.0-IT50.0RCKI~XI~OFACOiO.l350PSISIRICIL~lSKRIKSS.C.ItPKRCKMTTUSKPLUCCIKCRIHODKLt,32fDFLUIDTKHPKRATURKBURST,$.00FTI)PKAr.7.50fTI~>4ClJo1500.D1250.0Ea:1000.0Io750.00250.000.0oooanTIHK(SKCICI~nCICICIC7anfaaFiure14.3.2-0cFluidTemperature-DECLG(CD=0.4) 7000.0NCEOFA12+T.t,350tSLCO<0.11SIlCONFlCVNATlONCOXTNOLECCSHOOELSCoO.IOECLCFXr1.12l-FLOVNATECONESOTTOH1ITOP~tilLIWnI%5000.02500.0~V0.0<500.0-7000.0~4TTHE(SEC)Figure111.3.2-9aCoreFlow(TopandBottom)-DECLG(CD=0.0) 7000.0RCEOfAIt+Tit.350tSICD~0CISIICOIIfICURATIONCONTROLECCHODCLSCD>0~COCCLCfXYDI~IZ1-fLOVRATKCORESOTTOH-IITOf~IIILJWVlDl5000.02500.0ICI0.0<500.0A00.0-7000.0CIClTIHEISEC)Figure14.3.2-9bCoreFlow(TopandBottom)-DECLG(CD=0.6)

f000.0RGfOfAl2+T.P.350PSlCDi0~1l90lCONflGURATIOIICOIITROLECCSMODELSCD>0.4DECLGfXY>l.l2l-fLOVRATEC3REBOTTOMIITOPiI~I5000.02500.0a0.0-2500.0-5000.0-1000.0TIMEISEC)Figure14.3.2-9cCoreFlow(TopandBottom)-DECLG(CD=0.4)

l.T500RGC)1Xl1DFACD'.0350PSlS/R/C/LSCRlCSS~G.l2PKRCCNTTUIlPLUGGlHGRlHODCL2+320FOFLOODRATCIIN/SEC)l.5000l.2500ul.NNW0.7500CCCIo0.5000O.ZXO0.0ChCICI888TlHC(SEC)Figure1'.3.2-10aRefloodTransient-CoreInletVelocity-DECK(CD=0.B)

2.0000l.7500ACEI~XllOFACD~0.C)50PSIS/A/C/L4~SEAIESSC.I2PERCENTTUSEPLUGCINGAIHODEL2.)20FOFLOODRATEIIII/SECTI.5000I.2500uI.0000R0.F5004)IOO(y)O0.50000.25000.0CICI8TIHE(SEC)8888Figure14.3.2-10bRefloodTransient-CoreInletVelocity-DECLQ(CD=0.6) 2.00001.1500RCKI4XIIOFACOz0.a350PSISIRICIL+45fRIKSS.C~12PER(EKffVBLPLUCCIHC81HOOEL2.9XOf0fL000RAffIIH/SECI1.50001.25001.0000i@II-0.1500Cl0.50900.25000.0ClClClClClClCIatIHCISECIClClClFigure14.3.2-10cRefloodTransient-CoreinletYelocity-DECK(CD=0.)CD=0.4)I

Zo.ooot1+500ACElaXllOFACo~O.l)50tSlS/A/C/LioSEalESs.c.lZrEaCElttulEPLucclkcllHOOELZ.)ZOFOVAtEIILEVELlFt)l5.000lZ.500l0.000Ila.~'.5000+5.ooooZ.50000.088tlHElSECl."i"ureill.3.2-11aBefloodTransient-CoreandDowncomerllaterLevelsDECLG(CD=0.8)88 Ile500iGEIiXIIOFACD~O.C3SOPSIS/iiCIL4lSERIESS.G.IZPEACENIlUBEPLUGGINGIINOOELZ+320EoUAIEiLEVELlflII$.000fl.Soo~r.S000I0.000MICO~S.OOOO0.0888lIHEISEC)888I'i'Ure1II.3.2-11bRefloodTransient-CoreandDowncoloerI.'aterLevels.DECLC(CD=0.6)

Zo.noo.II.%GORGKIIXIIOFA(0-0~lI$0P5I5/R/C/I.S(RIES'S.G.IZPORC(RITUB(PLUGGING8IMOO(tZ.gloFoUGLIERI.EVE.llrllli.000I2.500I0.000I~/.coco~s;00002.50000.0CIOCIC7C)C)IIHEISKGICIC)C7Fi-"ure14.3.2-11cPefloadTransient-CoreandDmlncomerplaterLevelsnCLG(CD=0.4)

F00.0hCEOfAIZ+f.t,350tSICO>O.I1SllCOhfICVhATIONCOH'lhOLECCSHODELSCD~O+ODECLCfXY>laIRACCVH.fLOllCl>I500.0~JEJl000.0500.00~0.0TIHE(SEC)~VFigure14.3.2-12aAccumulatorFlow(Blowdown)-DECLG(CD=0.8)

%00.0In0.0RCEOFAIZ+T.P.350PSlCOi0~C19I1COIIFlCURA110IICOIIlROLECCSHOOELSCO+0~COEFXY+loltACCUHoFLOW~n1500.0IR50.0X~JlJ1000.0F50.000.0CIoFIMEISEC]n.Figure14.3.2-12bAccumulatorFlaw(Blawdawn)-DECLG(CD=0.6) 2000.0I350.0RCEOFAl2+T.P.350PSICOi0~iI9llCOHFIGURhlIOllCOHIROLECCSMODELSCO~0.4OECLCI*I~I2ACCVM.FLOM1500.0CSI2SO.OXLJEPl000.0190.00ZSO.OO0.0CI~nTIMEISEC)CICIAJCICICIIrlFigure1II.3.212cAccuAccunulatorFlow(Blowdown)-DECLG(CD=O.II) 8.00007.0000RGE14X14OFACOBRK0.8N2INJECTION44SERIESS.G.12PERCENTTUBEPLUGING81MO[)ELSAFETYINJECTIONFLOW~6.0000.LalI-5.0000~4.0000n-3.000"I-Lal-2.00001.00000.0CDCDnCDnCDCDCDnAJCDCDnCDCDnCDCDCDCDTINE(SEC'ONOS)Figure1Il.3.2-13aPumpedECCSFlaw(Reflood)-(CD=0.8)-

8.00007.0000RGE14X14OFACOBRK0.6N2INJECTION44SERIESS.G.12PERCENTTuBEPLuGINGe1MOOELSAFETYINJECTIONFLOM~6.0000M~s.oooo~4.0000-3.0000Lsf-2.0000I-LaJ1.00000.0CDCDCDCDCDCDCDCDCDCUCDCDCDCY)CDCDCDCDIlLS3CDCDCDTIME(SECONOS)Figure14.3.2-13bPunpedECCSFlow(Refload)-(CD=0.6) 8.00007.GOOORGE14X14OFACDBRK0.4N2INJECTIONSERIESS.G.12PERCENTTUBEPLUGING81MODELSAFETYINJECTIONFLOW-6.0000Laf7-5.0000~4.00003.0000Ld-2.00000-LJ1.00000.0CDCDCDCDCDCDCDCDCDAJCDCDCDCDCDCDCDCDCDCDCDCDTINE(SECONDS)Figure14.3.2-13cPumpedECCSFlow(Reflood)-(CD=0.4)

50.000P40.000RGE14X14OFACDBRK0.8N2INJECTION44SERIESS.G.12PERCENTTUBEPLUGING.81MODELCONTAINMENTPRESSURE30.000-20.00010.0000.0CDCDCDCDCDCDCDCDCDCDCUCDCDCDCDCDCDCDCDCDCDCDCDTIME(SECONDS)Figure14.3.2-14aContainmentPressure-DECLG(CD=0.8)

50.000RGE14X14OFACOBRK0.6H2INJECTION44SERIESS.G.12PERCENTTUBEPLVGING81MOOELCONTAINHEHTPRESSURE40.00030.0000.0CDCDCDCDCDCDCDCDCDAJCDCDCDCDCDCDCDCDCD4CDCDTINE(SECONDS)Fi'ure1~I.3.2-14bContainmentPressure-DECLG(CD=0.6) 50.000RGE14X14OFACDBRK0.4N2INJECTION44SERIESS.G.12PERCENTTUBEPLUGING81MODELCONTAINMENTPRESSURE40.00030.0004lMICJlCo-20.000C/lE/lLalCL10.0000.0CDCDCDCDCDCDCDCDCDCDCUCDCDCDCDmCDCDC)CD4SCDCDCDCDLATIME(SECONDS)Fi"urlII.3.2-1IIcContainmentPressure-DECLG(CD=O.II) l.7500RGEOF/IZ+T.l'.350PSICO~0.I1901COIIFICVRATIOIICOATAOLECCSHOOEL5C0$0.1OECL'CFXY~I.IZPOVER~,1.50001.25001.00000.75000.5000O.Z5000.0C7OoHC)TIHEl5EC)FigureI4.3.2-15CorePowerTransient-DECLG(CD=0.4)

S.OOEK)1RGEOFA12+T.P.lSOPSICOI0.11981CORFIGURATIONCOKTROLE(CSHOOELSCO*0.iOECLGFXV*I.12BREAKERERGT1.0OEKllII.OCEAN)12.0OEK)TI.OOE&7O.OOCIOTJHEISEC)CICICIIIIFigure14.3.2-16Dreal'nergyReleasedtoContainment-DECLG(CD=0.4)

I-LJLa.LaLalCD1250.01000.0RGEIOX10OFACDBRK0.4N2INJECTION04SERIESS.G.12PERCENTTUBEPLUGING81MODELCONDENSINGHEATTRANSFERCOEFFICIENT~750.00telI-K500.00CDIjlLalCDCD250.000.0CDCDCDCDCDCDCDCDCDCDAJCDCDClCDmCDCDCDCDCDCDCDCATINE(SECONOS)Figure14.3.2-17Containment',lailCondensingIleatTransferCoefficient-DECLG(CD=0.4)

II~IIIN