ML17227A389

Proposed Tech Specs Section 3.5.1 Re Safety Injection Tank Min Pressure Reduction

ML17227A389
Person / Time
Site:	Saint Lucie
Issue date:	04/21/1992
From:	FLORIDA POWER & LIGHT CO.
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~~~~St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment SafetIn'ection TankMinimumPressureReduction ATTACHMENT 1St.LucieUnit2Marked-up Technical Specification Page3/45-1'F204230201 920421PDRADOCK05000289PPDR 3t'0';5-"

'tNGBCY'OttE~CNRING SYSTEMSECCS3/4.5.1SAFETYINJECTION TANKSiV.~sLIMITINGCONDITION FOROPERATION

~I3.5;1EachReactorCoolantSystemsafetyinjection tankshallbeOPERABLEwith:a.:The,isolation valve..open, b.Acontained boratedwatervolumeofbetween1420and1556cubicfeet,I~A'<'c.Aboronconcentration ofbetween1720and2100ppmofboron,andI~d.AniItrogcn~cover.-pressure ofbetween@'nd'650psig.APPIICABILITY:

MOOES1;2,3",and4".Sob.ACTION:Withonesafetyinjection tankinoperable, exceptasaresultofaclosedisolation valve,restoretheinsuperable.tank toQPERA8LE.')atua Awithin1"ho'uh,or.

be'in.af;ljast HdTsTACIBY'withinthenext;6'o'ursandinHOTSHUTDOWN"wi4hiri thefollowing 6hours.+th'one,'sat'ety ing'ection tang,inoperabIe'.due,.'to)gei~1atlqn valvebetngchas'ed,either,.iaeedfgCqty,open,'he "isolatian.vie er.Pe,.inatleast'HOT STANDB'(within 1'ouran4tjein'OT,SHUTGGMtfmithin thenext.12hours...SURVEILLANCE.

REUIREMENTS.:

~l4.5;,l-..lI Eachsafari@;injection tankshallbedemonstrated.OPFRABI.E;

...a.Atleastonceper12hoursby:l.Verifying (bytheabsenceofalarms)thecontained boratedwatervolumeand.nitrogencoverpressureinthetanks,and2;"Verifying'hat

'eachsafetyinjection tankisolation valveisopen.thpressurZerpress'ut"e,'..cfihaterI thaiorequalto1750psia.'hen pressur-izerpressureis1'essthan1750psia",atleastthreesafetyinjection.

tanksshallbeOPERABLE, eachwithaminimumpressureof.,235psigandamaximumpressureof650psigandacontained'ater vol'umeofbetween1250and1556cubicfeetwitha.boronconcentration ofbetween,1720 and2100ppmofboron.Withallfours'afetyinjection tariks'OPERAHL'E, eachtankshallhaveaminimumpressureof235psiganda.maximumpressureof650.psiganteacaqtaiqed

.watervolumeofBetween833'nd.'1556 cubicfeetwithaboihconcentratian ofbetween1720and2100ppmofb'oron.InMODE4withpressuriziir pressUrelessthan276psia,thesafe.'yinjection tanksmaybeisolated.

ST.LUCIE"UNIT23/45"1IAmendment No.40 0$P St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment SafetInectionTankMinimumPressureReduction ATTACHMENT 2SAFETY"ANALYSIS Introduction TheproposedchangetotheSt.LucieUnit2,Technical Specifications reducesthesafetyinjection tank(SIT)minimumpressurefrom570psigto500psig.TheproposedchangemodifiesTechnical Specification 3.5.1.d,SafetyInjection Tanks,forSt.LucieUnit2.Theproposedchangeprovidesthebenefitofagreaterdifferential pressuremarginbetweentheSIToperating pressureandtheSITreliefvalvepressuresetpoint(669psig).ReducingtheSITLimitingCondition forOperation (LCO)to500psigmeanstheminimumSITpressurewouldbeapproximately 75percentofthere'liefvalvepressuresetpointwhichrepresents a10percentincreaseinmarginwhencomparedtocurrentconditions.

Thisadditional marginlessensthepotential forSITreliefvalveleakagethathasimpactedplantavailability inthepast.Discussion TheSITsensurethatasufficient volumeofboratedwaterwillbeimmediately forcedintothereactorcorethrougheachofthecoldlegsintheeventthereactorcoolantsystem(RCS)pressurefallsbelowthepressureoftheSITs.Thisinitialsurgeofwaterintothecoreprovidestheinitialcoolingmechanism duringlargeRCSpiperuptures.

ThelimitsonSITvolume,boronconcentration, andpressureensuretheassumptions usedforSITinjection inthesafetyanalysisaremet.Bycomparison, St.LucieUnit1SITnitrogencoverpressureisnormallysetbetween220psigand225psig,andtheUnit1Technical Specifications requiretheSITpressuretobebetween200psigand250psig.St.LucieUnit1has14x14fuelassemblyarraywhileSt.LucieUnit2hasa16x16fuel.ThehigherpressureoftheSt.LucieUnit2safetyinjection tankswasemployedtogainadditional LOCAmarginabovethemargingainedbythefuelassemblyarraychange.

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~~~~~~~~~Section6.3.3.1oftheSt.LucieUpdatedFinalSafetyAnalysisReport(UFSAR)liststhefollowing Emergency CoreCoolingSystem(ECCS)designcriteriafrom10CFR50.46:(1)Thecalculated maximum-fuel elementtemperature shallnotexceed2200'F.(2)Thecalculated totaloxidation ofthecladdingshallnowhereexceed17percentofthetotalcladdingthickness beforeoxidation.

(3)Thecalculated totalamountofhydrogengenerated fromthechemicalreactionofthecladdingwithwaterorsteamshallnotexceed1percentofthehypothetical amountthatwouldbegenerated ifallthemetalinthecladdingcylinders surrounding thefuel,excluding thecladdingsurrounding theplenumvolume,weretoreact.(4)Calculated changesincoregeometryshallbesuchthatthe.coreremainsamenabletocooling.(5)Afteranycalculated successful initialoperation oftheECCS,thecalculated coretemperature shallbemaintained atanacceptably lowvalueanddecayheatshallberemovedfortheextendedperiodoftimerequiredbythelong-lived radioactivity remaining inthecore.Attachment 4istheTechnical Evaluation, Reduction ofSafetyInjectionTankPressureMinimumSetpointforSt.LucieUnit2NuclearPowerP2ant,preparedbyABBCombustion Engineering.

Itprovidesthejustification foradecreaseintheSt.LucieUnit2minimumSITpressurefrom570psig.to500psig.Technical justification foroperation ofSt.Lucie"Cycle"7"'at a-reduced SITminimumoperating pressureof500psigisprovidedbyECCSperformance evaluations ofthesmallbreakloss-of-coolant accident(SBLOCA).

Sincethelargebreakloss-of-coolant accident(LBLOCA)analysisofrecordwasperformed with,anSITpressureof200psig,theproposedminimumSITpressureof500psigisbounded.Theseperformance evaluations demonstrate acceptable conformance with10CFR.50.46.Areviewofthenon-LOCAdesignbasesevents,in'ttachment 4,showsthat=noneoftheseanalysescalculate or-credit SITinjection intotheRCS.Therefore, thereduction ofSIT-minimum operating pressuresetpointhasnoimpactonpostulated non-LOCAdesignbasesevents.Althoughthestationblackoutevent(SBO)isoutsidethedesignbasesforUnit2,ananalysiswasperformed asacondition oflicenseattherequestoftheNRC.ThisanalysisappearsasSection15.10oftheUFSAR.Attachment 4provides' technical lt40ll'laf'J)()')fyj~'~)(j<<,g~,v'3y's.lQ%Ua~~4m+p~~gA4=v~4<.$&j~'N~4sra~~tlg~4 evaluation oftheSBOeventattheproposedminimumoperating pressureof500psig.This.evaluation demonstrates thattheoriginalconclusions presented inSection15.10.5oftheUFSARhavenotbeenadversely affected.

Theslightincreaseinthedifferential pressurebetweentheRCSandSITsmayhavetwoopposingeffectsonbackleakage fromtheRCSintotheSITs.First,theincreased differential pressurewilltendtoseatthecheckvalvesmorefirmly,andthusmaycauseaslightdecreaseintheprobability ofbackleakage intotheSITs.Second,theslightincreaseindifferential pressurebetweentheRCSandtheSITsmayslightlyincreasetherateofbackleakage intotheSITs,shouldbackleakage occur.Suchback-leakage wouldaffecttherequiredSITboronconcentration andlevel.Thereisnohistoryofback-leakage intotheSITsatSt.LucieUnit2orUnit1.Asachangeinlevelwouldalerttheoperators toanyaccompanying reduction inboronconcentration intheSITs,thereisessentially noprobability ofsuchbackleakagecontributing toanevent.Therefore, thereduction ofSITminimumpressurewillhavenosignificant effectontheprobability orconsequences ofback-leakagefromtheRCSintotheSITs.CONCLUSION eTheacceptability oftheproposedreduction oftheSITminimumoperating pressuredependsontheimpactonthepostulated SBLOCA,thepostulated LBLOCA,andthepostulated SBO.TheSBLOCAlimitingbreaksizeandassociated peakcladdingtemperature stronglydependontheSITpressure.

ReducingtheSITminimumoperating pressureto500psigforSt.LucieUnit2increases theSBLOCAlimitingbreaksizefrom0.0375ft2to0.0450ftandincreases thepeakcladdingtemperature from1771'Fto1905'F.Thisanalytical evaluation forSBLOCAwasperformed usingABBCombustion Engineering's NRCapprovedproprietary smallbreakevaluation model,Calculative MethodsfortheCESmallBreakLOCAEvaluation Model,CENPD-137(P),

datedAugust1974andCENPD-137(P)

Supplement 1,datedJanuary1977.Theanalysiswasperformed consistent withtherequirements of10CFR50AppendixK.Thisanalysisdemonstrated acceptable conformance with10CFR50.46.TheLBLOCAanalysisofrecordisforcycle3whichboundslatercycles.TheLBLOCAanalysiswasredoneforcycle2whenthecorepowerwasincreased from2560MWtto2700MWt.-TheLBLOCAanalysiswasredoneagainforcycle3withrevisedsteamgenerator tubeplugginglimits.ThisLBLOCAanalysiswasperformed withaSITpressureof200psig,acondition whichconservatively coversthe500psigSITpressureusedintheSBLOCAanalysis.

Thepeakcladdingtemperature fortheLBLOCAanalysisis2107'F.TheSBLOCAanalysiswithreducedSITminimumpressureremainslessthanthecurrentLBLOCApeakcladdingtemperature ofrecord.Therefore, the

'I~i~/+t,4Jk4~e~A%"Pg(.I-l*4flf"%~a LBLOCAcalculation remainsthe.limitinganalysisof..record forECCSperformance evaluation.

ThisLBLOCAanalysisalsoshowsacceptable

.conformance tothe10CFR50.46acceptance criteriaforECCSperformance insupportofthereducedvalueofSITminimumpressureof500psig.Attachment 4includesareviewofSBO,which.isoutsidethedesignbasisforSt.LucieUnit2butispartofthelicensing basis.TheSBOeventpostulates afourhourtimeperiodforrestoring ACpowerduringwhichprimarysubcooling andnaturalcirculation mustbemaintained.

TheSBOanalysisinUFSARSection15.10creditssomeSITinjection lateinthetransient.

Anassessment ofthisanalysis,.concluded thattheproposedreduction intheminimumSITpressurewoulddelaytheSITdischarge.

However,sufficient inventory remainsintheRCSthroughtheSBOtopreventvoidingintheRCSloopandthustopreventalossofnaturalcirculation.

Theconclusions presented intheUFSARregarding maintaining naturalcirculation andcoresubcriticality areunchanged.

Therefore, thereduction oftheSITminimumpressuresetpointto.-500'sig hasnoimpactontheSBOevent.Non-LOCAdesignbaseseventshavebeenreviewedtoevaluatetheimpactofdecreasing theSITminimumpressureto500psiginAttachment 4.ForSt.LucieUnit2,noneofthenon-LOCAeventscalculate orcreditSITinjection intotheRCS.Therefore, thereduction inSITminimumoperating pressuresetpointhasnoimpact,onotherpostulated non-LOCAsafetyanalyses.

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~~~~St.LucieUnit2DocketNo.50-389ProposedLicenseAmendment SafetIn'ection TankMinimumPressureReduction ATTACHMENT 3DETERMINATION OFNOSIGNIFICANT HAZARDSCONSIDERATION Thestandards usedtoarriveatadetermination thatarequestforamendment involvesanosignificant hazardsconsideration areincludedintheCommission sregulation, 10CFR50.92,whichstatesthatnosignificant hazardsconsiderations areinvolvediftheoperation ofthefacilityinaccordance withtheproposedamendment wouldnot(1)involveasignificant increaseintheprobability orconsequences ofanaccidentpreviously evaluated; or(2)createthepossibility ofanewordifferent kindofaccidentfromanyaccidentpreviously evaluated; or(3)involveasignificant reduction inamarginofsafety.Eachstandardisdiscussed asfollows:(1)Operation ofthefacilityinaccordance withtheproposedamendment wouldnotinvolveasignificant increaseintheprobability orconsequences ofanaccidentpreviously evaluated.

Reducingthesafetyinjection tank(SIT)minimumpressuredoesnotinvolveasignificant increaseintheprobability ofa-.loss-of-coolant accident-(LOCA),-

since-the-SITs--are--passive systemsandhavenoeffectonthereactorcoolantsystem(RCS)untilafterthedepressurization oftheRCSduetoaLOCA.ReducingtheSITminimumpressureto500psigforSt.LucieUnit2increases thesmallbreakloss-of-coolant (SBLOCA)limitingbreaksizefrom0.0375ftto0.0450ftandincreases peakcladdingtemperature from1771'Fto1905'Fforthenewlimitingbreaksize.Thecalculated peakcladdingtemperature (1905'F)fortheSBLOCAanalysiswithreducedSITminimumpressureremainslessthanthecurrentlarge'.break loss-of-.coolant(LBLOCA),analysis.

peakcladding.temperature.

of.2107'F..

ThisLBLOCAanalysiswasperformed assumingaSITpressureof200psig,acondition whichconservatively coverstheproposedminimumSITpressureof500psig.Therefore, althoughtheconsequences ofaSBLOCAareincreased

slightly, theLBLOCAcalculation remainsthelimitinganalysisofrecordforemergency corecoolingsystem(ECCS)performance evaluation.

TheLBLOCAanalysisofrecordisforcycle3whichhasbeenshowntoboundlatercycles.ThisLBLOCAanalysisalsoshowsacceptable conformance to10CFR50.46,Acceptance CriteriaforECCSperformance forlightwaternuclearpowerreactors, insupportoftheproposedminimumSITpressureof500psig.ThisECCSperformance evaluation forSt.LucieUnit2wasperformed consistent withNRCapprovedmethodology and10CFR50AppendixKcriteria.

TheLBLOCAanalysiswasperformed assumingaSITpressureof200psig,therefore, thereisnoincreaseintheconsequences ofaLBLOCAduetoreducingtheminimumSITpressureto500psig.Non-LOCAdesignbasiseventshavebeenreviewedtoevaluatetheimpactofdecreasing theminimumSITpressureto500psig.ForSt.LucieUnit2,noneofthenon-LOCAeventscalculate orcreditSITinjection intotheRCS,sincenoneofthenon-LOCAaccidents resultinRCSdepressurization belowtheSITmaximumpressuresetpoint.

Therefore, thereduction oftheSITminimumpressuresetpointhasnoincreaseintheconsequences

.ofnon-LOCAdesignbaseseventsduetoreducingtheminimumSITpressureto500psig.Thestationblackoutevent,(SBO),whichispresented inSection15.10.5oftheUFSAR,hasbeenreviewedtoevaluatetheimpactofdecreasing theSITminimumpressureto500psig.WiththeSITpressurereducedto500psig,SITinjection isinitiated priortotheoccurrence ofvoidingintheRCSloops,thuspreventing alossofnaturalcirculation.

Therefore, reducingtheSt.LucieUnit2Technical Specification limitforSITminimumnitrogencoverpressurefrom570psigto500psigdoesnotinvolveasignificant increaseintheprobability.

or*.consequences=='of-.an=-.accident previously evaluated.

(2)Useofthemodifiedspecification wouldnotcreatethepossibility ofanewordifferent kindofaccidentfromanypreviously evaluated.

Therearenoadditional failuremodesfortheSITsduetoreducingthenitrogencoverpressurefrom570psigto.500.psig.TheSITs"are-passive"systems andhave-no.effect-on

-the,RCSuntilafterthedepressurxzation of-.the-RCS.,due to.a.LOCA.Therefore, reducingtheSt.LucieUnit2Technical Specification limitforSITminimumnitrogencoverpressurefrom570psigto500psigdoesnotcreatethepossibility ofanewordifferent kindofaccidentfromanypreviously evaluated.

~Qe~JiltP'JIp~,q~~4~V'1%f'"k (3)Useofthemodifiedspecification wouldnotinvolveasignificant reduction inamarginofsafety.TheSBLOCAanalysiswiththeSITpressureof500psigsatisfies thecriteriaof10CFR50.46andremainsboundedbytheLBLOCAanalysisofrecord.TheLBLOCAanalysiswas.performed assuminga.SITpressureof200psig.ReviewoftheSBOanalysiswiththeSITpressureof500psigdemonstrates thattheoriginalconclusions, presented inUFSARSection15.10.5,havenotbeenadversely affected.

Therefore, reducingtheSt.LucieUnit2Technical Specification limitforSITminimumnitrogencoverpressurefrom560psigto500psigdoesnotinvolveasignificant reduction inamarginofsafety.Basedontheabove,wehavedetermined thattheproposedamendment doesnot(1)involveasignificant increaseintheprobability orconsequences ofanaccidentpreviously evaluated, (2)createtheprobability ofanew-ordifferent kindofaccidentfromanypreviously evaluated, or(3)involveasignificant reduction inamarginofsafety;andtherefore doesnotinvolveasignificant hazardsconsideration.

+I

~~~~St.LucieUnit2DocketNo.50-389,ProposedLicenseAmendment SafetIn'ection TankMinimumPressureReduction ATTACHMENT 4TECHNICAL EVALUATION REDUCTION OFSAFETYINJECTION TANKPRESSUREMINIMUMSETPOINTFORST.LUCIEUNIT2 4PgKlp OPS-92-0385 ENCLOSURE 1TECHNjtCAL JUS'IXFICATION forREDUCTION OFSAFETYINJECTION TMWPRESSURESETPOINTTO500PSIGforST;LUCIEVI.'GT2NUCLEARPOWERPLANTPreparedforFloridaPower4Light'yOperations AnalysisABBCombustion Engineering NuclearServicesMARCH1992Combustion Engineering, Inc.JLItItr<IrIeASEABROWNBOVERI pff'i'iL~VIl4tIrv'EC.BPtP Thisreportprovidestechnical justification foradecreaseintheSt.LucieUnit2minimumoperating safetyinjection tank(SIT)pressurefrom570psigto500psig.ReducingthisTechnical Specification LimitingCondition forOperation (LCO)valueprovidesagreaterdifferential pressuremarginbetweentheSIToperating pressureandtheSITreliefvalvepressuresetpoint(669psig).Thisadditional marginlessens.thepotential forchallenges totheSITreliefvalveandconcurrent reliefvalveleakagesthathaveimpactedSt.LucieUnit2availability'n thepast.Technical justification foroperation ofSt.LucieUnit2Cycle6atthereducedSITminimumpressureof500psigisprovidedbyECCSperformance evaluations ofthesmallbreakloss-of-coolant accident.

ReducingtheSITminimumoperating pressureto500psigincreases theSBLOCAlimitingbreaksizefrom0.0375ftto0.045ftandincreases thepeakcladdingtemperature from1771'Fto1905'F.Thisincreased PCTforSBLOCAremainslessthanthelimitingECCSperformance analysislargebreakLOCAPCTof2107'F.TheLBLOCAanalysiswasperformed withaminimumSITpressureof200psig,therefore, theLBLOCAcalculated resultsalreadyconservatively coveroperation ataminimumSITpressureof500psig.TheseECCSperformance evaluations demonstrate acceptable conformance with10CFR50.46.

Areviewofthenon-LOCAdesignbasiseventsshowsthatnoneofthesesafetyanalysescreditSITinjection intotheRCStomeettheacceptance criteria.

Therefore, thereduction oftheSITminimumopeFating pressuresetpointhasnoadverseimpactonthenon-LOCAdesignbasisevents.Anassessment oftheStationBlackoutEventshowsthatevenwithdelayedSITactuation duetothereducedminimumoperating pressuresetpoint, primaryreactorcoolantsubcooling inthehotlegsandreactorcoolantsystemnaturalcirculation aremaintained throughout theassumedfourhourtimeperiodforrestoring ACpowerduringthispostulated event.

ll SECTIONPAGE"ANNXcjf'fABLKYof~coNTEN$

832.1Introduction andSummary2.2MethodofAnalysis2.3Results2.4Conclusions 5Y@7%NNCCVN9KNQMxYNN9%NNNC6 4.1Non-LOCADesignBasisEvents4.2StationBlackoutEvent'X~AXNKNNS 485151556061 I'4AQitfiQ'r Thisreportprovidestechnical justification foradecreaseintheSt.LucieUnit2minimumoperating safetyinjection tank(SIT)pressurefrom570psigto500psig.ReducingthisTechnical Specification LimitingCondition forOperation (LCO)valueprovidesagreaterdifferential pressuremarginbetweentheSIToperating pressureandtheSITreliefvalvepressuresetpoint(669'sig).

ReducingtheLCOto500psigmeans'hattheminimumSITpressureforoperation wouldberoughly75%ofthereliefvalvepressuresetpointwhichrepresents a1(Nincreaseinmargincomparedtocurrentconditions.

Thisadditional marginlessensthepotential forchallenges totheSITreliefvalveandconcurrent reliefvalveleakagethathaveimpactedSt.LucieUnit2availability inthepast.Thisreportislimitedtotheengineering evaluation necessary tojustifytheplantchangetoreducetheSITminimumoperating pressuresetpointfrom570psigto500psig.Thisreportdoesnotinclude(1)anevaluation oftherelatedinstrument (loop)inaccuracies oruncertainties, (2)PC/H,technical specification, FSARorrelatedchangepackages, or(3)addressing changesintheSITmaximumoperating pressuresetpoint.

Primarily, thisreportaddresses theimpactofreducingthetechnical specification,LCO onminimumSITpressureforthepostulated smallbreakloss-of-coolant accident(SBLOCA).

TheSBLOCAlimitingbreaksizeandassociated peakcladdingtemperature (PCT)stronglydependontheSITpressure.

ReducingtheSITminimumoperating pressureto500psigforSt.LucieUnitfincreases theSBLOCAlimitingbreaksizefrom0.0375ftto0.045ftandincreases thePCTfrom1771'Fto1905'F.Thisanalytical evaluation forSBLOCAwasperformed usingABBCombustion Engineering's NRCapprovedsmallbreakevaluation modeldescribed inReference 1.Thisanalysisdemonstrates acceptable conformance with10CFR50.46 whichpresentstheAcceptance CriteriaforEmergency CoreCoolingSystems(ECCS)forLightWaterNuclearPowerReactors(Reference 2).Thecalculated PCT(1905'F)fortheSBLOCAanalysiswithreducedSITminimumoperating pressureremainslessthanthecurrentlargebreakloss-

~IIU'L)lq%l of-coolant accident(LBLOCA)PCTofrecord.ThePCTfortheLBLOCAanalysisis2107'F.ThisLBLOCAanalysiswasperformed withaSIToperating pressureof200psig,acondition whichconservatively coversthe500psigSITpressureusedintheSBLOCAanalysis.

Therefore, theLBLOCAcalculation remainsthelimitinganalysisofrecordforECCSperformance evaluation.

TheLBLOCAanalysisofrecordisforCycle3whichhasbeenshowntoboundlatercyclesthroughCycle6.ThisLBLOCAanalysisalsoshowsacceptable conformance to10CFR50.46 Acceptance CriteriaforECCSperformance insupportofthereducedvalueofSITminimumoperating pressureof500psig.ThisLBLOCAECCSperformance evaluation forSt.LucieUnit2Cycle6wasperformed atapowerlevelof2754NMt(2700HMtplus2Xuncertainty) andatapeaklinearheatgeneration rate(PLHGR)of13kw/ft.Thisreportincludesareviewofthenon-LOCAdesignbasiseventstoIevaluatethepotential impactofdecreasing theLCOforSITminimumpressureto500psig.ForSt.LucieUnit2,noneofthenon-LOCAeventscreditSITinjection intothereactorcoolantsystem.Therefore, thereduction oftheSITminimumoperating pressuresetpointhasnoadverseimpactonthenon-LOCAdesignbasiseventanalyses.

Thisreportincludesanassessment ofthevalidityofthestationblackouteventdocumented inSection15.10oftheFSAR(Reference 9)withregardtotheimpactofreducingtheminimumSITpressuresetpoint.

Inthisassessment, theresultspresented inReference 9areusedtodemonstrate thatevenwithdelayedSITdischarge intotheRCSresulting fromloweringtheSITsetpointto500psig,sufficient liquidinventory remainsintheRCStopreventvoidingintheRCSloopandlossofnaturalcirculation.

Therefore, thisassessment showsthattheconclusions presented inReference 9regarding maintaining primarynaturalcirculation andcoresubcriticality forthefourhourdurationofthepostulated eventareunchanged withthereducedSITpressuresetpointof500psig.

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2.1Introduction andSummarThissectionpresentstheresultsoftheECCSperformance evaluation fortheSmallBreakLoss-of-Coolant Accident(SBLOCA)forSt.LucieUnit2,Cycle6,withtheminimumoperating safetyinjection tank(SIT)pressuredecreased from570psigto500psig.ThisECCSperformance evaluation demonstrates conformance with10CFR50.46 whichpresentstheAcceptance CriteriaforEmergency CoreCoolingSystems(ECCS)forLightWaterNuclearPowerReactors(Reference 2).Theevaluation with500psigminimumoperating SITpressuredemonstrates acceptable SBLOCAECCSperformance forSt.LucieUnit2.Sections2.2,2.3,and2.4presentthemethodofanalysis, results,andconclusions, respectively.

2.2HethodofAnalsisThecalculations reportedinthissectionwereperformed usingABBCombustion Engineering's NRCapprovedsmallbreakevaluation modeldescribed inReference 1.ThismethodofanalysisisthesameasthatusedfortheSt.LucieUnit2Cycle6SBLOCAECCSperformance analysis(Reference 3).Acompleteevaluation ofSBLOCAinvolvestheuseoffourcomputercodes.Blowdownhydraulics arecalculated usingtheCEFLASH-4AS computercode(Reference

~Refloodhydraulics arecalculated usingtheCOHPERC-II code(Reference 5).Fuelrodtemperatures andcladdingoxidation percentages arecalculated usingtheSTRIKIN-II (Reference 6)andPARCH(Reference 7)codes.Detailsoftheinterfacing ofthesecodesarediscussed inReference 1.FortheECCSperformance evaluation withthereducedSITpressure, onlytheCEFLASH-4AS andPARCHcodeswereneededfortheanalysis.

LoweringtheSITpressurewhilekeepingallotherparameters andmethodsthesameresultsinachangeinthelimitingbreaksizeandachangeinthe f~'i4t~tt'vf'4A' calculated PCT.TheCEFLASH-4AS codeisusedtoprovideprimarysystemthermal-hydraulics foraspectrumofbreaksizestoidentifythenewlimitingbreaksizeandthePARCHcodeprovidesthehotrodheat-upcalculations duringthecoreboil-offperiodofthetransient.

Forlicensing calculations, thelimitingbreaksizeistypically thelargestbreakforwhichthecladdingtemperature heat-upduringcoreboil-offuncoveryisreversedwithonlyHPSIdeliverytotheprimarysystemandwithoutSITdischarge.

Inthisanalysis, PCToccursjustafterabriefmomentary discharge fromtheSITswhichisfollowedbyHPSIdrivenrepressurization andcorerecovery.

ForSBLOCA,theCOHPERC-II codeisusedtoanalyzethecorehydraulic response(recovery) following continuous SITdischarge.

TheEvaluation Modelmethodology inReference Iforanalyzing corerefloodfollowing SITdischarge usingCOHPERC-II assumesthatcontinuous SITinjection causesallsteaminthecoretwo-phasefluidtocondense.

Thiscondition doesnotapplyforthebreaksizesofthisstudywhereSITdischarge isbriefandnotcontinuous.

forthebreaksizesinthisSBLOCAstudy,corerefloodfromHPSIdeliveryandbriefdischarge fromtheSITsisanalyzedadequately withtheCEFLASH-4AS codewhichgivesboththethermalandhydraulic responseofthecorerefloodperiod.Therefore, analysisofcorerefloodusingtheCOHPERC-II codeisnotneededforthelimitedrangeofbreaksizesinthisstudy.IntheABBC-Emethodology forSBLOCA,theSTRIKIN-II codeisusedtoanalyzethehotrodthermalresponseduringtheperiodofforcedconvection whendeparture fromnucleateboilingmayoccur.ForthebreaksizesofthisSBLOCAstudy,acladdingtemperature increaseduringtheforcedconvection periodduetodeparture fromnucleateboilingdoesnot,usuallyoccur,asindicated bythe0.0375ftbreakresultsfromtheanalysisperformed forCycle6inReference 3.SincethePCTcalculated withthePARCHcodeoccursduringtheboil-offuncoveryperiodofthetransient, analysisoftheearlyblowdownhotrodresponseusingtheSTRIKIN-II codeisnotneededforthelimitedrangeofbreaksizesinthisECCSevaluation.

Also,theearlyblowdownhotrodresponsehasanegligible influence ontheboil-offuncoveryperiodwhendeparture fromnucleateboilingdoesnotoccur.

71eplI;YC4' 1"TheECCSanalysisassumptions forthisanalysiswithreducedSITpressureareunchanged fromtheevaluation modelassumptions (Reference 1).TheworstsinglefailureforanalysisofSBLOCAisthefailureofoneoftheemergency dieselgenerators tostart.Thisfailureresultsintheminimumsafetyinje'ction available tocoolthecore.Therefore, basedonthisassumption, thefollowing injection pumpswerecreditedintheSBLOCAanalysis:

'a~b.C.d.oneHighPressureSafetyInjection (HPSI)pumponeLowPressureSafetyInjection (LPSI)pumponeChargingpumpfourSafetyInjection TanksForbreaksinthepumpdischarge leg,itisalsoassumedthatallsafetyinjection flowdelivered tothebrokencoldlegspillsoutthebreak.Thisresultsinthefollowing reducedinjection flowdelivered tothecore:'a~b.C.d.75%oftheflowfromoneHPSIpump50XoftheflowfromoneLPSIpump4ÃoftheflowfromoneChargingpump(basedonworstflowsplit)10ÃoftheflowfromthreeSafetyInjection TanksAsdescribed inReference 1,theSBLOCAanalysesassumethatoffsitepowerislostuponreactortrip.Asaresult,thesafetyinjection pumpswereassumedtostartaftera30seconddelay(fordieselgenerator startupandloadsequenqjgg) following asafetyinjection actuation signal.TheECCSperformance analysisconsidered aspectrumofcoldlegbreaksinthereactorcoolantpumpdischarge leg.Asdemonstrated inpreviousanalyses, discharge legbreaksaremorelimitingthanotherbreaklocations.

Thespectrumofbreakswereselectedtoshowthenewlimitingbreaksizeresulting fromthereduction inSITpressure.

I'tJ Thepreviouslimitingbreaksize,0.0375ft,isnotinfluenced bythereducedSITpressure, sincethecladdingtemperature heat-upisreversedbyHPSIdeliveryalone.LargerbreaksizesdependonSITdischarge toreversethefuelcladdingheat-up.ByreducingSITpressure, theselargerbreaksizes'ust waitforthereactorcoolantsystempressuretodecreasetothelowerSITsetpointpressurebeforereceiving SITdischarge totheprimarysystem.Theselargerbreaksizesdepressurize morerapidly,loseinventory outthebreakatagreaterrate,andexperience greaterratesofcoolantflashing.

But,theselargerbreaksizesalsoreceivemoreHPSIdeliverytotheprimarysystemwiththelowerprimarysystempressurepriortoSITdischarge.

Whiletheselargerbreaksizecaseswaitfor.SITactuation atthelowerpressuresetpoint, thecladdingcontinues toheat-uptohighertemperatures.

Eventually HPSIdeliveryatthelowerprimarysystempressurewillbegreaterthantheinventory lossbyflashing, coreboil-off, andspillageoutthebreakandwillreversethecladdingheat-upjustpriortoornearthemomentofSITdischarge, thusestablishing anewlimitingbreaksize.BriefSITdischarge totheRCScanoccurjustpriortoreachingthetimeofpeakcladdingtemperature andmaythroughitsimpactonthecoretwo-.phasemixturelevelterminate thecladdingtemperature riseand/ormaycausethecoreaxialelevation ofpeaktemperature tochangetothenexthighestnode.Thenewlimitingbreaksizeidentified bythisanalysisisthe0.045ftcoldlegbreak.2.3ResultsTheanalysisdemonstrated the0.045ftbreaktobethelimitingsmallbreakwithapeakcladdingtemperature of1905'Fandamaximumcladdingoxidation percentage oflessthan7%.Theresultsaresummarized inTable2.3-1.Thetimesatwhichsignificant eventsintheperformance oftheECCSoccurredforeachbreaksizearelistedinTable2.3-2.Table2.3-3providesalistofthesignificant parameters andinitialconditions used,intheanalysis.

PP4a$I,/kCi,'~klj"'IA"k,.i~l Thetransient valuesofparameters whichmostdirectlyaffectfuelrodperformance areshowninFigures2.3-1through2.3-4(seeTables2.3-4and2.3-5).Thefollowing parameters aregraphically presented foreachbreaksize:(a)Normalized TotalCorePower(b)InnerVesselPressure(c)BreakFlowRate'd)InnerVesselInletFlowRate(e)InnerVesselTwo-Phase MixtureLevel(f)HotSpotHeatTransferCoefficient (g)CoolantTemperature atHotSpot(h)HotSpotCladdingSurfaceTemperature Figure2.3-5summarizes thepeakcladdingtemperature resultsofthespectrumanalysis.

The0.045ftbreakwasdetermined tobethelimitingsmallbreak.Forbreakssmallerthan0.045ftcoreuncoverybeginslaterwhenthefissionproductdecayheatgeneration islessand,hence,thedepthofuncoverywillbeless.forbreaksgreaterthan0.045fthmtheresulting systemdepressurization rateisfastersuchthatthecladdingtemperature riseisterminated earlyinthetransient bySafetyInjection Tanksactuation.

2.4Conclusions Basedontheresultsofananalysisofaspectrumofsmallbreaksinthecoldlegatthereactorpumpdischarge withtheminimumoperating pressureofthesafetyinjection tanksreducedfrom570psigto500psig,itis'concluded thatoperation ofSt.LucieUnit2Cycle6isacceptable.

Theresultsofthelimiting0.045ftsmallbreakresultedinapeakcladdingtemperature of1905'Fandamaximumcladdingoxidation percentage oflessthan7%,demonstrating theSBLOCAECCSperformance tobelesslimitingthanthatforthelargebreakLOCAperformance resultsgiveninSection3.0.

Avs*

Table2.3-1St.LucieUnit2FuelRodPerformance SummarySmallBreakLOCASpectrumwithSafetyInjection TankPressureof500psigBreakSize(ft)PeakCladTemperature axial('F)location"'eak LocalCladOxidation axialP)location"HotRodCladOxidation"'1o) 0.0375ft/PD0.0400ft/PD0.0450ft/PD(0.0500ft/PD17710.9018360.9519050.9518410.855.240.906.730.906.690.904.610.90<0.65<0.81<0.77<0.53(a)Hotrodoxidation valuesaregivenasaconservative indication ofcore-wide oxidation (b)PDatPumpDischarge (c)Axiallocationgivenasafractionofactivecoreheight10

~~

Table2.3-2St.LucieUnit2TimesofInterestforSmallBreakLOCASpectrumwithSafetyInjection TankPressureof500psig(secondsafterbreak)BreakSize(ft)HPSI'"'ump OnLPSISI~~PumpOnTanksOnHotSpotPeakCladTemp.Occurs0.0375ft/PD0.0400ft/PD0.0450ft/PD0.0500ft/PD130120110100(a)(a)(a)(a)28072408203217632261.22351.72034.31776.2(a)Calculation terminated beforetimeofLPSIpumpactivation.

(b)"PumpOn"and"TanksOn"aremeanttoindicate"RCSInjection Begins"

Table2.3-3St.LucieUnit2SmallBreakECCSPerformance AnalysisSignificant Parameters andInitialConditions arameterCorePowerLevelat102KofNominal(MWt)CoreAverageLinearHeatRateat102KofNominal(kw/ft)PeakLinearHeatGeneration Rate(PLHGR)HotAssembly, HotChannel(kw/ft)CoreInletTemperature

('F)CoreOutletTemperature

('F)SystemFlowRate(ibm/hr)CoreFlowRate(ibm/hr)NumberofTubesPluggedPerSteamGenerator

~SafetyInjection Tank(SIT)GasPressure(psig)moderator Temperature Coefficient (dp/'F)AxialShapeIndex(ASIU)Low'ressurizer PressureTripSetpoint(psia)ISafetyInjection Actuation SignalSetpoint(psia)HighPressureSafetyInjection PumpShutoffHead(psia)Values27544.9015.0552.0603.8136.1xlO(1)131.1xlO1250500(2)+0.2xlO-0.151650.01500.01214(1)SystemFlowrateconsistent with363,000gpm(2)LBLOCAusesSITGasPressureof200psig12 r.yy4~

Table2.3-4St.LucieUnit2SmallBreakLOCASpectrumI'eSieandLocation0.0375ftBreakinPumpDischarge Leg0.0400ftBreakinPumpDischarge Leg0.0450ft.BreakinPumpDischarge Leg0.0500ftBreakinPumpDischarge LegAbbreviation 0.0375ft/PD0.0400ft/PD0.0450ft/PD0.0500ft/PD~Fiures2.3-12.3-22.3-32.3-413

Table2.3-5St.LucieUnit2Variables PlottedasaFunctionofTimeforEachSmallBreakLOCAintheSpectrumVariableFigureNormalized TotalCorePowerInnerVesselPressureBreakFlowRateInnerVesselInletFl'owRateInnerVesselTwo-Phase HixtureLevelHeatTransferCoefficient atHotSpotCoolantTemperature atHotSpotHotSpotCladdingSurfaceTemperature I*RefertoFigures2.3-1Athrough2.3-4H.14 lt~i~=~vus~a~4t~W~'Iu

'1.25O~1.00OOc0.75C5~~0.50O0.250100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantCOREPOWER0.0375FT28REAKINPUMPDISCHARGE LEGFigure2.3-1A I'~hlk~e 240020001600w12008004.00010002000300040005000TIME(SECONDS)

FLORIDAPOWER8cUGHTCO.St.Lucie2NuclearPowerPlantINNERVESSELPRESSURE0.0575FT2BREAKINPUMPDISCHARGE LEGFigure2.0-1B

>>l~"P'PIt'4~I~~C'II1Q%~

12001000800~~600I-O4002000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPewterPlantBREAKFLOWRATE0.0375FT2BREAKINPUMPDISCHARGE LEGFigure2.8-1C17

)h4'liftIVK'4' 4000032000~24000~16000I-O~~800000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cUGHTCO.St.Lucie2NuclearPowerPlantINNERVESSELINLETFLOYDRATE0.0375FT28REAKINPUMPDISCHARGE LEGFigure2.3-1D18 0f~)II4

>32F24OCIJJa16OTOPOFCOREOMOFCORE001000200030004000TIMEtSECONDS)5000FLORIDAttJPOWER8cLIGHTCO.St.Lucie8NuclearPowerPlantINNERVESSELTWO-PHASE MIXTURELEVEI0.0375FT2BREAKINPUMPDISCHARGE LEGFigure8.3-1E19 t~A~A9'l-tJW1'C~oE.va 10000010000I-4JOLLIOC3QIJJ1000100101010002000300040005000TIME(SECONDS)

FLORIDAPOWER8cLIGHTCO.St.Lucie8NuclearPowerPlantHEATTRANSFERCOEFFICIENT ATHOTSPOT0.0375FT2BREAKINPUMPDISCHARGE LEGFigure2.3-1F20

~Wt~wEW10,'p(>>I' 12001000800LLI6004002000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.LuciePNuclearPowerPlantCOOLANTTEMPERATURE ATHOTSPOT0.0375FT2BREAKINPUMPDISCHARGE LEGFigure2.5-1G21 1ir%4([I4~V4s'V 2200,1900PJt/J~1600I-~1300IJJ~1000O.700400010002000300040005000TIME(SECONDS)

FLORIDAPOWER8cLIGHTCO.St.Lucie8NuclearPowerPlantHOTSPOTCLADDINGSURFACETEMPERATURE

0.0 375FT2BREAKINPUMPDISCHARGE

LEGFigure2.3-1H22 Isab~~

O1.00OOo0.75C)~.Q-0.50O0.250'000IOOO2000.30004000T~ME(sEcowos) 5000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantCOREPOWER0.0400FT2BREAKINPUMPDISCHARGE LEGFigure2.3-2A23 e4I~t~0~W,I~r~e*~4'II&wf'oalllIfllII~ld.j~lII-240020001600w120080040000100020003000TIME(sE:coNos) 40005000FLORI3APOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantINNERVESSELPRESSURE0.0400FT2BREAKINPUMPDISCHARGE LEGFigure2.8-2B24 WA~,JAyt/~p1 12001000890600I-O4002000l0002000300040005000TIME(SECONDS)

FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantBREAKFLOWRATE.0.0400FT2BREAKINPUMPDISCHARGE LEGFigure2.8-2C25 I>~l~0~g~'f 4000032000PJ24000w16000O80000000TIME(SECONDS) 80000)000200040005000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantINNERVESSELINLETFLOWRATE0.0400FT2BREAKINPOMPDISCHARGE LEGFigure2.8-2D26

~WI~'I~a~Pe~"

4032P-24a16TOPOFCOREBOMOFCORE010002000300040005000TIME(SECONDS)

FLORIDAPOWER8cLIGHTCO.St.LucieBNuclearPowerPlantINNERVESSELTWO-PHASE MIXTURELEVEL0.0400FT2BREAKINPUMPDISCHARGE LEGFigure2.3-BE27

~4Vs1&%4ehl~e\kj~iPVt~Aes>ertmeC.,Jr1't0 100000ICVI10000IJJOLLIO10001001010100020003000t',sEcoNos) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPoorerPlantHEATTRANSFERCOEFFICIENT ATHOTSPOT0.0400FT2BREAKINPUMPDISCHARGE LEGFigure2.8-2F28 sI~~Q~rt 140012001000800~-~600400010002000.3000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantCOOLANTTEMPERATURE ATHOTSPOT0.0400FT2BREAKINPUMPDISCHARGE LEGFigure2.3-2G29

~eI~I,~'>>">>j>>>>4<~I")>>

22001900w1600I-~1300~1000O7004000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie8NuclearPowerPlantHOTSPOTCLADDINGSURFACETEMPERATURE

0.0 400FT2BREAKINPUMPDISCHARGE

LEGFigure2.3-2H30 0I'gu4~*4glltlCtA,k' 1.501.25O~1.00OOo0.75N~~0.50'OZ0.254000TIME(SECONDS) 01000200030005000FLORIDAPOKER8cLIGHTCO.St.Lucie8NuclearPowerPlantCOREPOWER0.0450FT2BREAKINPUMPDISCHARGE LEGFigure2.3-3A

'~

240020001600~1200MMQQ80040000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie2~~NuclearPowerPlantINNERVESSELPRESSURE0.0450FT2BREAKINPUMPDISCHARGE LEGFigure2.3-3B32

)e,-4 12001000800600O4002000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantBREAKFLOWRATE0.0450FT2BREAKINPUMPDISCHARGE LEGFigure2.3-3C33 t4co>r'4~~g~<AI"~

4000032000FJ24000~16000I-O~~80000-80000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.LucieP.NuclearPowerPlantINNERVESSELINLETFLOWRATE0.0450FT28REAKINPUMPDISCHARGE LEGFigure8.3-3034 4032LLIP-24OC016OTOPOFCOREOMOFCORE00100020003000(sEcowos) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPoorerPlantINNERVESSELTWO-PHASE MIXTURELEVEL0.0450FT2BREAKINPUMPDISCHARGE LEGFigure2.8-0E35 J4(~rEp4BPlt~t 100000IIj0000I-LLIOIJJO10001001010100020003000VIMEtSECONDS)40005000FLORIDAPOWER8cLIGHTCO.St.Lucie8NuclearPowerPlantHEATTRANSFERCOEFFICIENT ATHOTSPOT0.0450FT2BREAKINPUMPDISCHARGE LEGFigure2.S-SF36 gIt 140012001000LJJ5800LIJ6004002000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie?NuclearPapererPlantCOOLANTTEMPERATURE ATHOTSPOT0.0450FT2BREAKINPUMPDISCHARGE LEGFigure2.3-3G37

~IW~VI"PI~~~~lW%~

22001900IJJ~1600I-~1300<C.K1000Ci7004000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie8NuclearPowerPlantHOTSPOTCLADDINGSURFACETEMPERATURE

0.0 450FT2BREAKINPUMPDISCHARGE

LEGFigure2.3-3H38 I',g,1I(~,

O1.00OOo0.75CiN~0.50O0.2500'100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantCOREPOWER0.0500FT2BREAKINPUMPDISCHARGE LEGFigure2.3-4A39

'4~le~

240020001600wl20080040000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantINNERVESSELPRESSURE0.0500FT2BREAKINPUMPDISCHARGE LEGFigure2.3-484p I'

1200j000800600O4002000100020003000TIME(SECONDS) 40005000FLORIDAPOWER8cLIGHTCO.St.LucieP.NuclearPowerPlantBREAKFLOWRATE0.0500FT2BREAKINPUMPDISCHARGE LEGFigure2.8-4C

~h0l~0'-~

4000032000~24000mw1600080000010002000000(sEcoNDs) 40005000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantINNERVESSELINLETFLOWRATE0.0500FT2BREAKINPUMPDISCHARGE LEGFigure2.8-4D42

&tsla, 4032IJJP-24>CW016OTOPOFCOREBOMOFCORE00100020003000TIME(SECONDS) 40005000FLORIDAPOWER8c'LIGHTCO.St.Lucie8NuclearPowerPlantINNERVESSELTWO-PHASE MIXTURELEVEL0.0500FT2BREAKINPUMPDISCHARGE LEGFigure2.0-4E43 I,~RlI'LIeMOM,aa 10000010000tsJV44bJOC3QLJJ(A'L1000100l001000200030004000(sEcoNDs) 5000FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantHEATTRANSFERCOEFFICIENT ATHOTSPOT0.0500FT2BREAKINPUMPDISCHARGE LEGFigure2.3-4F44 IAPII 12001000800IJJ600<002000010002000300040005000TIMEt',SECONOS)

FLORIDAPOWER8cLIGHTCO.St.Lucie8NuclearPoorerPlantCOOLANTTEMPERATURE ATHOTSPOT0.0500FT2BREAKINPUMPDISCHARGE LEGFigure2.8-4G45 a4llII~~1If 22001900~1600I-~]300IJJ~10000O700400010002000300040005000TIME(SECONDS)

FLORIDAPOWER8cLIGHTCO.St.Lucie2NuclearPowerPlantHOTSPOTCIADDINGSURFACETEMPERATURE

0.0 500FT2BREAKINPUMPDISCHARGE

LEGFigure2.8-4H46

~84f 22002000LIJCi~1800LYI-~16000C3K~14OO120010000.03790.04000.04250.04500.0475BREAKAREA(SQFT)0.0500FLORIDAPOWER8cLIGHTCO.St.Lucie8NuclearPowerPlantPEAKCLADDINGTEMPERATURE VERSUSBREAKAREAFigure2\3547

~tri,s1fpVJCar4"k>k, Thelargebreakloss-of-coolant accident(LBLOCA)analysisofrecordforSt.LucieUnit2isforCycle3(Reference 8).TheCycle3analysishasboundedlatercycles,namely,Cycles4,5,and6,becauseallcurrentcycle-specific inputdatahasbeenshowntobethesameorlessseverethantheCycle3data.TheCycle3inputdataandresultsofReference 8,whichapplyconservatively toCycle6arepresented inTables3.0-1and3.0-2,respectively.

TheresultsofthisECCSperformance evaluation demonstrate apeakcladdingtemperature notinexcessof2107'F,apeaklocalcl'adding oxidation percentage.

of7.62K,andapeakcore-wide claddingoxidation percentage oflessthan0.7%,comparedtotheECCSacceptance criteriaof2200'F,17K,and1%,respectively.

TheseresultswerebasedonaninitialSITpressureof200psig,acondition alreadymoreadverseforECCSperformance thanthe500psigSITminimumpressureanalyzedforSBLOCAinSection2.0.Therefore, theCycle3LBLOCAresultsapplyconservatively toCycle6withaminimumSIToperating pressureof500psig.Inconclusion, operation ofSt.LucieUnit2Cycle6withaminimumSITpressureof500psigatacorepowerlevelof2754NWt(102Kof2700HWt)andapeaklinearheatgeneration rateof13.0kw/ftisinconformance with10CFR50.46.

48

~Paramete Table3.0-1St.LucieUnit2LargeBreakECCSPerformance AnalysisSignificant Parameters andInitialConditions aluesCorePowerLevelat102%ofNominal(HWt)CoreAverageLinearHeatRateat102KofNominal(kw/ft)PeakLinearHeatGeneration Rate(PLHGR)HotAssembly, HotChannel(kw/ft)PeakLinear,HeatGeneration Rate(PLHGR)HotAssembly, AverageChannel(kw/ft)CoreInletTemperature

('F)CoreOutletTemperature

('F)SystemFlowRate(ibm/hr)CoreFlowRate(ibm/hr)GapConductance atPLHGR'(Btu/hr-ft

-'F)FuelCenterline Temperature atPLHGR'('F)FuelAverageTemperature atPLHGR'('F)HotRodGasPressure(psia)'aHotRodBurnup(NWD/HTU)

NumberofTubesPluggedPerSteamGenerator Augmentation FactorSafetyInjection Tank(SIT)GasPressure(psig)InitialContainment Temperature

('F)27544.9013.011.57552.0603.8136.lx10(1)131.lxl0146032962102'118103814301.00200(3)90(1)SystemFlowrateconsistent with363,000gpm(2)STRIKIN-II valuesathotrodburnupwhichyieldhighestPCT(3)SBLOCAandnon-LOCAuseSITGasPressureof500-650psig49 t>>

Table3.0-2St.LucieUnit2ResultsforLimitingBreakSize(0.6DfG/PD)~Paramete PeakCladdingTemperature

('F)TimeofPeakCladdingTemperature (seconds)

TimeofCladdingRupture(seconds)

PeakLocalCladdingOxidation (5)TotalCore-Mide CladdingOxidation P)Value<210726644.747.62<0.7050 f"lh.lIRIP[

Thissectionpresentstheassessment ofotherDesignBasisEvents(DBEs)andthestationblackouteventregarding thereduction oftheSITminimumoperating pressuresetpoint.

Section4.1reviewsthenon-LOCADBEstodetermine whethertheSITinventory wascreditedinanyoftheseeventsfortheSt.LucieUnit2safetyanalysesofrecord.Section4.2assessesthestationblackoutevent.StationblackoutisoutsidethedesignbasisforSt.LucieUnit2butispartofthelicensing basis.Thestationblackouteventpostulates afourhourtimeperi'odforrestoring ACpowerduringwhichprimarysubcooling andnaturalcirculation mustbemaintained.

ThestationblackouteventdoescreditSITinventory formaintaining naturalcirculation.

4.1Non-LOCADesinBasisEventsThenon-LOCADesignBasisEvents(DBEs)werereviewedtodetermine whethertheSafetyInjection Tankinventory wascreditedintheSt.LucieUnit2safetyanalysesofrecord.Inaddition, theimpactofdecreasing theSITgaspressureontheresultsofthenon-LOCAeventswasevaluated.

TheSITswillinjectduringseveredepressur izationevents,releasing highlyboratedliquidinventory intotheRCS.Theboratedliquidinsertsnegativereactivity inthecore,enhancing theshutdownmarginandmitigating apossiblereturntocriticality.

Decreasing theSITpressure(actuation setpoint) woulddelaythepossibleintroduction oftheboratedinventory intotheRCSandcouldreducethemargintocriticality.

Table4.1-1presentsalistoftheSt.LucieUnit2non-LOCADBEs.DBEswhichresultinaseveredepressurization areidentified inthisTablebyarrowsintheleftmargin.Theseareeventsduringwhichthereactorcoolantsystem(RCS)pressuredecreases belowthesafetyinjection actuation signal(SIAS)setpointandtheHPSIpumpsshutoffhead.Thenon-LOCADBEsresulting insuchasevereRCSdepressurization are:51 Jj~kP4I'~tgOttCQglpk,tlI0~~

1)Inadvertent OpeningofaSteamGenerator SafetyValveorAtmospheric DumpValve2)Post-Trip ReturntoPowerforSteamSystemPipingFailures(SteamLineBreaks)3)Pressurizer PressureDecreaseEvents(Inadvertent OpeningofthePressurizer PowerOperatedReliefValves-PORVs)4)SmallPrimaryLineBreakOutsideContainment (LetdownLineBreak)5)SteamGenerator TubeRuptureEventOftheaboveDBEs,theNSSSsimulation oftheInadvertent OpeningofthePressurizer PORVswasterminated beforetheRCSpressurestabilizes.

Thisisduetothefactthatthepost-trip NSSSbehaviorforthiseventfallswithinthespectrumofconsidered LOCAsandisnotofanyinterestwithrespecttotheDNBcriterion ofthisanalysis.

AsaLOCA,thepost-trip NSSSbehaviorofthiseventiswithinthedomainaddressed inSection2.0ofthisreport.Reviewoftheremaining DBEswasperformed todetermine whetherthecalculated minimumRCSpressureisbelowthecurrentSITminimumsetpointpressureof570psig(585psia).ThissurveyshowsthattheminimumRCSpressureduringanyoftheaboveDBEsis661psig(676psia)whichoccursduringtheInadvertent OpeningofaSteamGenerator SafetyValveorAtmospheric lumpValveevent.ForthePost-Trip ReturntoPowerHotZeroPowerSteamLineBreakEvent,theminimumRCSpressureat300seconds(theendofsimulation time)is668psig(683psia)andessentially stable.Theminimumcalculated pressures for,thesetwoeventsarestillabovethecurrentSITminimumsetpointpressureof570psig,resulting innodeliveryofSITinventory totheRCS.Sincenoneofthenon-LOCAeventsresultedinorcreditedthedeliveryofSITinventory, adecreaseintheminimumSITsetpointpressurewillhavenoadverseimpactontheresultsandconclusions oftheseevents.52 0yU Insummary,areviewofSt.LucieUnit2non-LOCAOesignBasisEventsanalysesshowsthatnocreditforSITinjection intotheRCSwastakenbytheseanalysesinordertoshowacceptable consequences.

Therefore, thereduction oftheSITminimumsetpointpressurehasnoimpactonthenon-LOCAsafetyanalyses.

53 EUIUIU,UkIl't$,UJ+'ICtU'U~4IP;P.$qu TABLE4.1-1ST.LUCIEUNIT2,DESIGNBASISEVENTSCONSIDERED INTHECYCLE2SAFETYANALYSISIncreaseInHeatRemovalByTheSecondary SystemA.B.C.~D.E*DecreaseinFeedwater Temperature IncreaseinFeedwater FlowIncreased HainSteamFlowInadvertent OpeningofaSteamGenerator SafetyValveorAtmospheric DumpValveSteamSystemPipingFailuresl.InsideContainment Pre-Trip2.OutsideContainment Pre-TripPowerExcursions 3.Post-Trip ReturntoPower2.3.4.5.6.7.DecreaseInHeatRemovalByTheSecondary SystemA.LossofExternalLoadB.TurbineTripC.LossofCondenser VacuumD.LossofNormalACPowerE.LossofNormalFeedwater F.*Feedwater SystemPipeBreaksDecreaseInReactorCoolantFlowrateA.PartialLossofForcedReactorCoolantFlowB.TotalLossofForcedReactorCoolantFlowC.*SingleReactorCoolantPumpShaftSeizure/Sheared ShaftReactivity AndPowerDistribution Anomalies A.Uncontrolled CEAMithdrawal fromaSubcritical orLowPowerCondition B.Uncontrolled CEAMithdrawal atPower'.C.CEADropD.CVCSMalfunction (Inadvertent BoronDilution)

E.StartupofanInactiveReactorCoolantSystemPumpF.*.ControlElementAssemblyEjectionIncreaseInReactorCoolantSystemInventory A.CVCSMalfunction B.Inadvertent Operation oftheECCSDuringPowerOperation DecreaseInReactorCoolantSystemInventory

~A.Pressurizer PressureDecreaseEvents~B.SmallPrimaryLineBreakOutsideContainment

~C.*SteamGenerator TubeRuptureHiscellaneous A.Asymmetric SteamGenerator Eventsddddd*Postulat'ed Accidents 54 E+tRghk!

4.2SttoacoutEventAnassessment wasmadeofthevalidityofthestationblackoutevent-documented inSection15.10oftheFSAR(Reference 9)withregardtotheimpactofreducingtheminimumSITpressuresetpoint.

Inthisassessment, theresultspresented inReference 9areusedtodemonstrate thateven'ithdelayedSITdischarge intotheRCSresulting fromloweringtheSITsetpointto500psigsufficient liquidinventory remainsintheRCStopreventvoidingintheRCSloopandlossofnaturalcirculation.

Therefore,.

thisassessment showsthattheconclusions presented inReference 9regarding maintaining primarynaturalcirculation udcoresubcriticality areunchanged withthereducedSITpressuresetpointof500pslg~Theinitialconditions forthereference analysisareforCycle1,andtherefore donotincludesteamgenerator tubepluggingandstretchreactorcorepowerlevelwhichhaveoccurredsincetheCycle1analysis.

Inthereference

analysis, creditistakenforoperatoractiontomaintainatleast10'Fprimarysystemsubcooling inthehotlegs.FortheCycle1analysis, subcooling ensurescondensation of.bubblesproducedinthecore,restricts voidformation duetoinventory losstothereactorvesselupperheadandpressurizer, andmaintains naturalcirculation.

Inthisassessment, theeffectsoftubepluggingandpowerupgradeonthecalculated massandenergybalancesareassumedtobeoffsetbythedifference insteamgenerator secondary operation thatwouldberequiredtomaintainthespecified

'hotlegsubcooling.

Thatis,assumingoperatoractionsfollowthesame"no-load" temperature program,theRCSinventory ataparticular RCSpressurefortheCycle1analysiswillbeverysimilartotheRCSinventory atthesame.RCSpressurecalculated withtubepluggingandstretchpower.Inarevisedanalysis, thetimingorsequenceofeventswouldbedifferent fromtheCycle1analysisduetothedynamiceffectsofincreased powerandreducedsteamgenerator heattransferarea,butcrediting operatoractiontomaintainthesamelevelofsubcooling (i.e.,thesametemperature) inthehotlegsresultsinacomparable RCSinventory andpressurerelationship.

Therefore, arevisedstation55 ra~<eiw4~s blackoutanalysisisnotrequiredfortheassessment discussed below,whichusestheRCSinventory andpressurerelationship intheCycle1referenceanalysistoshowthatvoidinginthehotlegswouldnotbecalculated tooccurwithareducedSITpressuresetpoint.

TheReference 9stationblackouteventanalysiswasperformed usingtheCESEC-III computercode,seeReference 10.Thisreference analysiscreditedSITdischarge totheRCSatabout12540secondsaftereventinitiation, whichwasbasedonaSITpressuresetpointof568psig.UsingtheReference 9calculated results,Table4.2-1presentstheprimarycoolantmassesinthepressurizer, reactorvesselupperhead,.andremainder oftheRCSforthetimeperiodbetween12000and14000seconds.ColumnsAand8ofTable4.2-1showthatthetimeof12000secondsrepresents acalculated condition intheRCSbeforetheSITpressuresetpointisreached(RCSpressureof632.9psig).Similarly, thetimeof14000secondsisacalculated condition intheRCSwhentheprimarypressureisbelowthereducedSITpressuresetpoiptof500psig(RCSpressureof496.6psig).Therefore, thereference analysisindicates thatthetimedelayinSITdischarge resulting fromreducingthepressuresetpointisroughly1460seconds.ThedatainColumnsAthroughHofTable4.2-1,istakenfromtheCESECoutputeditsfortheReference 9analysis.

ColumnIinTable4.2-1isthemassofliquidintheRCSexcluding theupperheadandthepressurizer.

Thisisobtainedbysubtracting theupperheadmass(ColumnG)fromtotalRCSmasswithoutpressurizer mass(ColumnF).ThetotalRCSmass'(Column J)including theupperheadandthepressurizer massesisobtainedbyaddingthevaluesofColumnsE(pressurizer mass)andF(massofRCSplussurgeline).ThevaluesatthebottomofeachcolumninTable4.2-1arethemassdifferences between12000and14000seconds.Table4.2-1showsthatfrom12000to14000seconds,11824.4ibm(ColumnC)wasaddedtotheRCSviaSITdischarge inthereference analysis.

Duringthesametimeperiod,1118ibm(ColumnD)leakedoutofthesystem.Therefore, basedonthedifference betweeninventory addedandinventory lost,thenetmassadditiontotheRCSis10706.4ibm.However,Table4.2-1alsoshowsthatCESECdetermines forthistimeperiodthatthetotal56 44.vo'1V'4'd~!ŽN't'll RCSmassincreased by16899ibm(lastentryinColumnJ).Thisdiscrepancy betweentheintegrated inventory balanceandthesummation oftotalRCSinventory (6192.6ibmintotalinventory gain)isaresultoftheCESECcomputercodenumerical integration scheme.Forconservatism, thelowervalueoftotalRCSmassisusedinthisassessment oftheimpactofthereducedSITpressuresetpoint.

Table4.2-1showsthatthe'otalmassofpressurizer andupperheadinventory at14000secondsis24559ibm(13670ibmfromColumnEplus10889ibmfromColumnG).Reducingthismassbythetotalintegrated SITdischarge of11824.4ibm(ColumnC)andbythe6192.6ibmwhichwasaddedbythecodenumerical scheme,produces6542ibm.Thisisthehypothetical totalmassinthepressurizer andtheupperheadat14000secondswithouttheSITinventory.

Reducingthishypothetical totalmassbythemassofsteamproducesthetotalmassofliquidinthepressurizer andupperhead.Thesteammassesinthepressurizer andupperheadaredetermined usingtheRCSparameters at12400secondsinthereference analysisbecausethisisthelastsetofinformation notinfluenced bySITdischarge.

Thisselection of12400seconds'isconservative relativetolatertimesinthereference analysisbecausetheCESEC-III calculation showsareduction invapormassasRCSpressuredecreases, aslongassubcooling inthehotlegsismaintained.

Therefore, themassofsteamthatexistsinthereactorvesselupperheadandpressurizer atthistimeprovidesaconservative estimatefortheamountofsteamthatwoul'dexistwhentheRCSpressuredecreases totheSITsetpointpressureof500psig.FromtheCESECmajoreditat12400seconds,themassofsteaminthepressurizer is1829.0ibm.Themassofsteaminthereactorvesselupperheadat12400secondis1339.5ibmwhichisbasedon(1)atotalupperheadvolumeof1165.4ft,(2)avoidfractionof0.86547(ColumnHat12400seconds),

and(3)asteamspecificvolumeof0.753ft/ibmatasaturated pressureof598.2psig(Column8at12400seconds).

Subtracting thesteammassofthepressurizer andupperhead(3168.5ibm)fromthetotalmassoftheseregions(6542ibm)showsthatapproximately 3373.5ibmofliquidwouldstillremainintheseregionsat14000seconds57 AyA9) withoutanySITinventory enteringtheRCS.ColumnBofTable4.2-1indicates thatwiththereducedpressuresetpointof500psig,theSITswillhavedischarged atsometimepriorto14000seconds.Therefore, itisconcluded thatRCSliquidinventory wouldstillbeenoughsothatsomeliquidremainedintheupperheadandthepressurizer.

Thismeansnovoidingwouldhavebeenintroduced intheRCSloops.Restricting voidingtotheupperheadin.theanalysisistheresultofassumingoperatoractiontomaintainatleast10'Fsubcooling inthehotlegsbyopeningtheatmospheric dumpvalvestoreducethesecondary systempressureandtemperature.

Theincreased heatremovalinthesteamgenerators causedbythelargertemperature difference acrossthesteamgenerator tubesreducestheprimarysystemtemperature.

Sincethesizeofthevoidisdetermined toremainconfinedbytheupperheadandpressurizer, naturalcirculation inthehotlegsismaintained.

Discharge ofboratedwaterfromtheSITspreventsadditional voiggrowth.Hence,theconclusions oftheReference 9analysisregarding'maintaining naturalcirculation intheRCSforthefirstfourhoursoftheeventareunchanged.

ItshouldbenotedthattheReference 9calculation didnotcredittheboroncontentsoftheSITsforthereactivity calculations.

Therefore, theconclusions oftheReference9analysiswithrespecttomaintaining coresubcriticality arenotaffectedbytheSITspressuresetpointchangeinthisevaluation.

Also,thisevaluation conservatively usedthelowerRCSinventory calculation fromCESECandassumednoSITdischarge through14000seconds,wheretheprimarypressureisbelowtheSITpressuresetpoint.

58 tlflegr'tI~,p TABLE4.2-1STATIONBLACKOUTEVENTINVENTORY SUMMARYTIMEPRESSINTEGRATED PSIGSIT,lbmINTEGRATED LEAK,lbmPZRRCSIncUPHMASS,lbmMASS,lbmUPPERHEADMASS,IbmUPPERHEADVOIDFRACTCESECTHERMAL-HYDRAULIC SUMMARYRCSw/oUPHRCSTOTALMASS,IbmMASS,Ibm12000632.9122001240012600622,3598.2559.112800549.713000544.513200539.10.00.00.02352.13707.94411.15226.510215A7.5710E+03 4.4990E+05 10332.88.6070E+03 4.4880E+05 10445.48.3660E+03 4.4890E+05 10560.84.8990E+03 4.5580E+05 106786.0010E+03 4.5660Et05 10790.27.7420E+03 4.5570Et05 10899A9.3640Et03 4.5510E+05 8.5076E+03 9.0452E+03 9.1083E+038.3772E+03 8.7643E+039.2671E+03 9.7185E+038.7677E-01 441392.48.6696E-01 439754.88.6547E-01 8.7782E-01 8.7086E-01 439791.7447422.8447835.78.6196E-01 446432.98.5398E-01445381.5457471457407457266460699462601463442464464134001360013800531.5508.1501.26259.99964.311092.611005.21.0760E+04 4.5520E+05 11115.61.0350E<04 4.6120E+05 11226.61.1840E+04 4.6140E>05 1.0093E+041.0127Et04 1.0396E+04 8.4734E-018.4657E-01 8.4185E-0144510745107345100448596047155047324014000496.611824.411333.41.3670E+04 4.6070E+05 1.0889E+048.3328E-01 449811474370DIFF11824.411186.0990E+03

.1.0800E+04 2.3814E+03 8418.616899DESCRIPTION OFCOLUMNHEADINGSA)TIME(SECONDS)

B)RCSPRESSURE(PSIG)

C)INTEGRATED SITDISCHARGE (LBM)D)INTEGRATED LEAKFROMRCS,TOTALEDFORTHETWOSIMULATED LEAKS(LBM)E)TOTALPRESSURIZER MASS,PRESSURIZER LIQUIDPLUSSTEAMMASS(LBM)F)MASSOFRCSPLUSSURGELINE(LBM)G)MASSINTHEUPPERHEAD(LBM)

H)UPPERHEADVOIDFRACTIONI)MASSINTHERCSLOOP,EXCLUDING MASSOFPRESSURIZER ANDUPPERHEAD(LBM)OBTAINEDBYSUBTRACTING COLUMNGFROMFJ)TOTALRCSMASS,INCLUDING THEPRESSURIZER ANDUPPERHEADMASSES(LBM)OBTAINEDBYADDINGCOLUMNSEANDFDIFF:THELASTROWPROVIDESTHEMASSDIFFERENCE BETWEEN14000AND12000SECONDSFOREACHPARAMETER 0CVI"lJI This'eport providesthetechnical basisfortheengineering evaluation whichdemonstrates thatareduction ofSITpressureminimumoperating setpointfrom570psigto500psigforSt.LucieUnit2Cycle6continues tomeettheacceptance criteriaforECCSperformance asdefinedbyIOCFR50.46.

Thisreportincludesthesupporting information andanalytical resultsforSBLOCA,LBLOCA,non-LOCAdesignbasistransients andthestationblackoutevent.Thecontainment peakpressureanalysiswasnotexaminedbythisstudy,however,thereduction ofSITpressureminimumoperating setpointto500psigdoesnotadversely affectthecontainment peakpressurebecausethetotalmassandenergyreleasedtothecontainment fromtheprimarysystemintheanalysisisnotchangedandbecausetheSITdischarges lessthanonesecondlateratthelowersetpoint.

Reducingthetechnical specification LCOvalueto500psigprovidesadditional differential pressuremarginbetweentheSIToperating pressureandtheSITreliefvalvepressuresetpoint(669psig).Thisadditional marginlessensthepotential forchallenges to'heSITreliefvalveandconcurrent reliefvalveleakagethathaveimpactedSt.LucieUnit2plantavailability.,

60 Nl'O'Lgj'It'd CENP0-137, "Calculative MethodsfortheCESmallBreakLOCAEvalu'ation Model,"Combustion Engineering Proprietary Report,August1974,(Proprietary).

CENP0-137, "Calculative Methods.fortheCESmallBreakLOCAEvaluation Model,"Supplement 1,January1977,(Proprietary).

Acceptance CriteriaforEmergency CoreCoolingSystemforLight-WaterCooledNuclearPowerReactors, FederalRegister, Vol.39,No.3-Friday,January4,1974.Letter,E.L.Trapp(C-E)toW.L.Parks,(FPLL),

"St.LucieUnit2.Cycle6ReloadSafetyEvaluation (RSE)Report,"F2-90-035, July6,1990.CENPD-133, Supplement 1,"CEFLASH-4AS, AComputerProgramforReactorBlowdownAnalysisoftheSmallBreakLoss-of-Coolant Accident,"

August1974,(Proprietary).

CENP0-133, Supplement 3,"CEFLASH-4AS, AComputerProgramforReactorBlowdownAnalysisoftheSmallBreakLoss-of-Coolant Accident,"

January1977,(Proprietary).

CENP0-134, "COMPERC-II, AProgramforEmergency Refill-Reflood oftheCore,"April1974,(Proprietary).

CENPD-134, Supplement 1,"COMPERC-II, AProgramforEmergency Refill-Reflood oftheCore(Modification),"

December1974,(Proprietary).

CENPD-134, Supplement 2,"COMPERC-II, AProgramforEmergency Refill-Reflood oftheCore,"June1985,(Proprietary).

CENPD-135, "STRIKIN-II, ACylindrical GeometryFuelRodHeatTransferProgram,"

April1974,(Proprietary).

CENP0-135, Supplement 2,"STRIKIN-II, ACylindrical GeometryFuelRodHeatTransferProgram(Modification),"

February1975(Proprietary).

CENP0-135, Supplement 4,"STRIKIN-II, ACylindrical GeometryFuelRodHeatTransferProgram,"

August1976,(Proprietary).

CENP0-135, Supplement 5,"STRIKIN-II, ACylindrical Geometry'uel RodHeatTransferProgram,"

April1977,(Proprietary).

61 PI1~

7.CENPD-138, "PARCH-AFORTRAN-IV DigitalProgramtoEvaluatePoolBoiling,AxialRodandCoolantHeatup,"August1974,(Proprietary).

CENPD-138, Supplement I,"PARCH,AFORTRAN-IV DigitalProgramtoEvaluatePoolBoiling,AxialRodandCoolantHeatup,"(Hodification),

February1975,(Proprietary).

8.CENPD-138, Supplement 2-P,January1977,(Proprietary).

Letter,E.L.Trapp(C-E)toJ.L.Perryman(FPKL),"ResultsofCE'sLargeBreakLOCA,Reevaluation forSt.LucieUnit2BasedonCE'sNew(1986)Evaluation Model,"F2-CE-R-137, April10,1987.9.FPEL,"St.LuciePlantUnit2,FSAR,"Amendment No.1,April1986.10.C-ETopicalReport,CENPD-107, "CESEC-DigitalSimulation ofaCombustion Eng'ineering NuclearSteamSupplySystem,"April1974.C-ETopicalReport,"CESEC-DigitalSimulation ofaCombustion Engineering NuclearSteamSupplySystem,"Enclosure 1-PtoLD-82-001,January6,1982.62 5