ML17308A504

Final Technical Evaluation Rept St Lucie Unit 1 Station Blackout Evaluation.

ML17308A504
Person / Time
Site:	Saint Lucie
Issue date:	08/17/1990
From:	SCIENCE APPLICATIONS INTERNATIONAL CORP. (FORMERLY
To:	NRC
Shared Package
ML17223B019	List: ML17308A504
References
CON-FIN-D-1311, CON-NRC-03-87-029, CON-NRC-3-87-29 SAIC-89-1643, TAC-68608, NUDOCS 9008310002
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AttachmentSAIC-89/1643TECHNICALEVALUATIONREPORTST.LUCIEUNIT1STATIONBLACKOUTEVALUATIONTACNo.68608ScienceApplicationsInternationalCorporationAnEmployee-OwnedCompanyFinalAugust17,1990Preparedfor:UKASENuclearRegulatoryCommissionWashington,DAC.20555ContractNRC-03-87-029TaskOrderNo.381710GoodridgeDrive,PDBox1303,MCLean,Virginia22102(703J821-4300OtnerSAICOtleesrstovqverqve.Boston,,CotortrdoSrrrrngs,Dayton.Hvntsvrtle.sosvegss.SosAngetes.OesRrttge.Ortenrto.trstoAtto,SenDregoSeeltteJnovesvn jII TABLEOFCONTENTSSection~Pae1.0ACKGROUND...........................................B2.0REVIEWPROCESS.......................................3.0VALUATION~~~~~~~~~~~~~~~~~~~~~~~~~~~~~o~~~~~~~~o~~~~E3.1ProposedStationBlackout.Duration..............3.2AlternateAC(AAC)PowerSource.................3.3StationBlackoutCopingCapability..............12163.4ProposedProceduresandTraining.................213.5ProposedNodifications..........................3.6qualityAssuranceandTechnicalSpecifications..222

34.0CONCLUSION

S..........................................2

45.0REFERENCES

...........................................27 TECHNICALEVALUATIONREPORTST.LUCIEUNIT1STATIONBLACKOUTEVALUATION1.0BACKGROUNDOnJuly21,1988,theNuclearRegulatoryCommission(NRC)amendeditsregulationsin10CFRPart50byaddinganewsection,50.63,"LossofAllAlternatingCurrentPower"(1).Theobjectiveofthisrequirementistoassurethatallnuclearpowerplantsarecapableofwithstandingastationblackout(SBO)andmaintainingadequatereactorcorecoolingandappropriatecontainmentintegrityforarequiredduration.ThisrequirementisbasedoninformationdevelopedunderthecommissionstudyofUnresolvedSafetyIssueA-44,"StationBlackout"(2-6).ThestaffissuedRegulatoryGuide(RG)1.155,"StationBlackout,"toprovideguidanceformeetingtherequirementsof10CFR50.63(7).Concurrentwiththedevelopmentofthisregulatoryguide,theNuclearUtilityManagementandResourceCouncil(NUMARC)developedadocumententitled,"GuidelinesandTechnicalBasisforNUMARCInitiativesAddressingStationBlackoutatLightWaterReactors,"NUMARC87-00(8).Thisdocumentprovidesdetailedguidelinesandprocedures.onhowtoassesseachplant'scapabilitiestocomplywiththeSBOrule.TheNRCstaffreviewedtheguidelinesandanalysismethodologyinNUMARC87-00andconcludedthattheNUMARCdocumentprovidesanacceptableguidanceforaddressingthe10CFR50.63requirements.TheapplicationofthismethodresultsinselectingaminimumacceptableSBOdurationcapabilityfromtwotosixteenhoursdependingontheplant'scharacteristicsandvulnerabilitiestotheriskfromstationblackout.Theplant'scharacteristicsaffectingtherequiredcopingcapabilityare:theredundancyoftheonsiteemergencyACpowersources,thereliabilityofonsiteemergencypowersources,thefrequencyoflossofoffsitepower(LOOP),andtheprobabletimetorestoreoffsitepower.

InordertoachieveaconsistentsystematicresponsefromlicenseestotheSBOruleandtoexpeditethestaffreviewprocess,NUNRCdevelopedtwogenericresponsedocuments.ThesedocumentswerereviewedandendorsedbytheNRCstaff(ll)forthepurposesofplantspecificsubmittals.Thedocumentsaretitled:1."GenericResponsetoStationBlackoutRuleforPlantsUsingAlternateACPower,"and2."GenericResponsetoStationBlackoutRuleforPlantsUsingACIndependentStationBlackoutResponsePower."Aplant-specificsubmittal,usingoneoftheabovegenericformats,providesonlyasummaryofresultsoftheanalysisoftheplant'sstationblackoutcopingcapability.LicenseesareexpectedtoensurethatthebaselineassumptionsusedinNUNARC87-00areapplicabletotheirplantsandtoverifytheaccuracyofthestatedresults.CompliancewiththeSBOrulerequirementsisverifiedbyreviewandevaluationofthelicensee'ssubmittalandauditreviewofthesupportingdocumentsasnecessary.FollowupNRCinspectionsassurethatthelicenseehasimplementedthenecessarychangesasrequiredtomeettheSBOrule.In1989,ajointNRC/SAICteamheadedbyanNRCstaffmemberperformedauditreviewsofthemethodologyanddocumentationthatsupportthelicensees'ubmittalsforseveralplants.Theseauditsrevealedseveraldeficiencieswhichwerenotapparentfromthereviewofthelicensees'ubmittalsusingtheagreedupongenericresponseformat.Thesedeficienciesraisedagenericquestionregardingthedegreeofthelicensees'onformancetotherequirementsoftheSBOrule.Toresolvethisquestion,onJanuary4,1990,NUMARCissuedadditionalguidanceasNUNARC87-00Supplementalguestions/Answers{16)addressingtheNRC'sconcernsregardingthedeficiencies.NUNRCrequestedthatthelicenseessendtheirsupplementalresponsestotheNRCaddressingtheseconcernsbyMarch30,1990.

2.0REVIBfPROCESSThereviewofthelicensee'ssubmittalisfocusedonthefollowingareasconsistentwiththepositionsofRG1.155:A.MinimumacceptableSBOduration(Section3.1),B.SBOcopingcapability(Section3.2),C.ProceduresandtrainingforSBO(Section3.4),D.Proposedmodifications(Section3.3),andE.gualityassuranceandtechnicalspecificationsforSBOequipment(Section3.5).ForthedeterminationoftheproposedminimumacceptableSBOduration,thefollowingfactorsinthelicensee'ssubmittalarereviewed:a)offsitepowerdesigncharacteristics,b)emergencyacpowersystemconfiguration',c)determinationoftheemergencydieselgenerator(EDG)reliabilityconsistentwithNSAC-108criteria(9),andd)determinationoftheacceptedEDGtargetreliability.Oncethesefactorsareknown,Table3-8ofNUMARC87-00orTable2ofRegulatoryGuide1.155providesamatrixfordeterminingtherequiredcopingduration.FortheSBOcopingcapability,thelicensee'ssubmittalisreviewedtoassesstheavailability,adequacyandcapabilityoftheplantsystemsandcomponentsneededtoachieveandmaintainasafeshutdownconditionandrecoverfromanSBOofacceptabledurationwhichisdeterminedabove.ThereviewprocessfollowstheguidelinesgiveninRG1.155,Section3.2,toassure:a.availabilityofsufficientcondensateinventoryfordecayheatremoval, IA b.adequacyoftheclass1Ebatterycapacitytosupportsafeshutdown,c.availabilityofadequatecompressedairforair-operatedvalvesnecessaryforsafeshutdown,d.adequacyoftheventilationsystemsinthevitaland/ordominantareasthatincludeequipmentnecessaryforsafeshutdownoftheplant,e.abilitytoprovideappropriatecontainmentintegrity,andf.abilityoftheplanttomaintainadequatereactorcoolantsysteminventorytoensurecorecoolingfortherequiredcopingduration.Thelicensee'ssubmittalisreviewedtoverifythatrequiredprocedures(i.e.,revisedexistingandnew)forcopingwithSBOareidentifiedandthatappropriateoperatortrainingwillbeprovided.Thelicensee'ssubmittalforanyproposedmodificationstoemergencyACsources,batterycapacity,condensatecapacity,compressedaircapacity,appropriatecontainmentintegrityandprimarycoolantmake-upcapabilityisreviewed.TechnicalSpecificationsandqualityassurancesetforthbythelicenseetoensurehighreliabilityoftheequipment,specificallyaddedorassignedtomeettherequirementsoftheSBOrule,areassessedfortheiradequacy.Thelicensee'sproposeduseofanalternateACpowersourceisreviewedtodeterminewhetheritmeetsthecriteriaandguidelinesofSection3.3.5ofRG1.155andAppendixBofNUNRC87-00.AnormalSBOreviewislimitedtothereviewofthelicenseesubmittal;itdoesnotincludeaconcurrentsiteauditreviewofthesupportingdocumentation.Suchanauditmaybewarrantedasanadditionalconfirmatory action.ThisdeterminationwouldbemadeandtheauditwouldbescheduledandperformedbytheNRCstaffatsomelaterdate.However,alimitednumberofconcurrentsiteauditreviewswereperformedinordertoobtainabenchmarkforlicenseeconformancewiththedocumentationrequirementsoftheSBOrule.TheSt.LuciesitewasoneofthesitesselectedbytheNRCforaconcurrentauditreviewoftheSBOsupportingdocumentation.ThisauditwasperformedbyajointNRC/SAICteam,headedbyanNRCstaffmember,onOctober17-19,1989atFloridaPowerandLight'sJunoBeachoffices.ThefollowingevaluationwaswrittenincoordinationwithNRCstaffandencompassesreviewofthelicensee'ssubmittal(10)andthelicensee'sresponsetoquestionsraisedduringthesiteauditreview(18).ThelicenseedidnotrespondtotheNUMARC87-00Supplementalguestions/Answers.Thelicenseeclaimedsimilarinformationhadbeenprovidedinhisresponse(18).

3.0EVALUATIONThelicensee,FloridaPowerandLightCompany(FPL),stated(10)thatthetotallossofACpowereventhasbeenaddressedinSection15c.4oftheSt.LucieUnit2UFSAR(13),andthattheanalysisdemonstratesthatSt.LucieUnit2couldsuccessfullywithstandacompletelossofACpowerforatleast4hours.SincetheSBOrule,10CFR50.63(2)(b),exemptsplantswhichhaveaddressedthecapabilitytowithstandanSBOeventaspartoftheirlicensingrequirements,Unit2willnotbeevaluatedinthisreport.3.1ProposedStationBlackoutDurationLicensee'sSubmittalThelicenseecalculated(10and18)aminimumacceptableSBOdurationoffourhoursfortheSt.LucieUnit1.Thelicenseestatedthatamodificationisnecessarytoattainthisproposedcopingduration.ThismodificationisdescribedinSection3.5.TheplantfactorsusedtoestimatetheproposedSBOdurationareasfollows:1.OffsitePowerDesignCharacteristicsTheplantACpowerdesigncharacteristicgroupis"P2"basedon:a.IndependenceofoffsitepowersystemcharacteristicsofIII2b.EstimatedfrequencyofLOOPsduetosevereweather(SQ)placestheplantinSMgroup"1,"c.EstimatedfrequencyofLOOPsduetoextremelysevereweather(ESM)placestheplantinESWGroup"4,"and d.Expectedfrequencyofgrid-relatedLOOPsoflessthanonceper20years.2.EmergencyAC(EAC)PowerConfigurationGroupThelicenseestatedthattheEACpowerconfigurationoftheplantis"A."TheSt.Luciesiteisequippedwithfouremergencydieselgenerators(EDG)whicharenormallyavailabletoeitherunit'ssafeshutdownequipment.Thelicenseestatedthatfollowingamodification(seeSection3.5)oneEDGwillbenecessarytoconcurrentlyoperatethesafeshutdownequipmentofbothunitsfollowingaLOOP.3.TargetEmergencyDieselGenerator(EOG)ReliabilityThelicenseeselectedatargetEDGreliabilityof0.95basedonhavinganuclearunitaverageEDGreliabilityof:a)greaterthan0.90forthelast20demandsforbothunits,b)greaterthan0.94forthelast50demandsforbothunits,andc)greaterthan0.95forthelast100demandsforbothunitsconsistentwiththeNUHARC87-00selectioncriteria.Additionally,FPLprovidedthefollowingEDGfailurecounts:EDG1A1B2A2BLast20~oemndsLast50~Demeds1011Last100DemandsReviewofLicensee'sSubmittalFactorswhichaffecttheestimationoftheSBOcopingdurationare:theindependenceofoffsitepowersystemgrouping,theexpectedfrequencyofgrid-relatedLOOPs,theestimatedfrequencyofLOOPsduetoSWandESM V

conditions,theclassificationofEAC,andtheselectionofEDGtargetreliability.Thelicensee'sestimatedLOOPfrequencydueSMconditionsisconsistentwiththeguidanceprovidedinNUHARC87-00,Table3-3,usingsingleright-of-waytransmissionlines.Thelicenseestatedthatsiteindependenceofoffsitepoweris"I2."Thelicenseestated(18)that,(seeFigure1),afterthelossofthenormalACpowersource(themaingenerator),thereisanautomatictransferofthesafeshutdownbusestothepreferredalternatepowersources(offsitepowerthroughthestart-uptransformers).Atthispoint,theSt.LucieUnit1safetybus1A3ispoweredfromstart-uptransformerST1Aandsafetybus1B3ispoweredfromstart-uptransformerSTlB.Thelicenseealsoadded:Upontheloss(failure)ofonestart-uptransformer(STlAorST1B),amanualtransfer(through1A4or2A4)isavailabletotheUnit2start-uptransformer(ST2AorST2B)ofthesametrain.Thismanualtransfercanbeaccomplishedin30minutes.2.Followingalossofpowertoastart-uptransformer(STlorST2),theconnectedemergencybusinUnit1canbepoweredfromoneoftheemergencybusesinUnit2throughtheproposedclass1Ecross-tiemodificationbetweentheunits.Basedontheabove,weagreewiththelicenseethatthisconfigurationcouldplaceSt.LucieUnit1ingroup"I2"providedthateachstart-uptransformerandun."auxiliarytransformerhassufficientcapacitytosupplytheloadsononedivisionofbusesinoneunitandonedivisionofemergencybusesintheother.Otherwise,an"I3"offsitepowergroupingshouldbeconsidered.Thelicensee'sestimationofremainingfactorswasnotconsistentwiththeguidanceprovidedinRG1.155andNUHARC87-00.Thefollowingsummarizesourfindings:

EASTRCSTR1NTRST2ASTfAtILRBproposedmodification)))C3$GXiaAuSTLUCKPLANTSIMPLIFIEDONE-LINEDIAGRAMFIGURE1 meenACPwerConfiuratinACG--ThelicenseestatedthattherearefourredundantEDGs,andthatonlyoneisrequiredtoachieveandmaintainsafeshutdownatbothunits,therefore,theEACpowerconfigurationisgroup"A."However,thisassessmentdoesnotconformtotheNUMARC87-00,Section3.2.2,Part2Bguidance,sinceoneEDGdoesnothaveadequatecapacitytocarrythefullLOOPloads(12and13)ofbothunits.St.LuciehastwonormallydedicatedEDGsperunitwhichautomaticallyrespondtotheLOOP-causedneedsoftheconnectedunit.Thisone-out-of-twoperunitEDGconfigurationresultsinanEACclassificationofgroup"C."xtremelSevereWeatherGrou--Thelicensee'sestimationofESMgroup"4"fortheSt.Luciesiteisbasedontheresultsoftwostudies:Thefirst,performedfor.theNRCbySandiaNationalLaboratory(SNL)(14),usedwinddatafromtheMASH-1300report,andthesecond,performedbyDamesandMoore(15),aconsultanttoFPL,usedwinddatafromfourseparatestudies:TheNationalHurricaneCenter/Neumann(NHC),theNationalBureauofStandards(NBS),theUniversityofWesternOntario(UWO)andtheFederalEmergencyManagementAgency(FEN).Theresultsofthesestudiesofthefrequencyofhurricanewindspeedsgreaterthan125mphrangefrom2.5E-4/yr.(FENdata)to7E-3/yr.(UMOdata).ThesedataindicatethatthesiteshouldbeinESWgroup"4."IftheNationalOceanicandAtmosphericAdministration(NOAA)data,whichisgiveninTable3-2ofNUNARC87-00andisbasedon100yearsofweatherdata,weretobeusedthesitewouldbeinESMgroup"5,"withanestimatedfrequencyofESMof1.7E-2/yr.Thisfrequency(1.7E-2/yr.)isabout2.5timeslargerthanthehighestfrequencyestimatedbythelicensee.Thelicenseeneedstoresolvethedifferencebetweentheseresults,oruseESMgroup"5"fortheSt.LuciesiteperNUNRC87-00Table3-2.OffsitePowerDesinCharacteristicPGrou--St.Luciehasnotexperiencedanygrid-relatedLOOPsofgreaterthan1/2hourinduration.Occurrenceofonesucheventwouldplacetheplantinthe"P3"group.However,bothNUNRC87-00andNUREG-1032considertheSt.Luciesitetobevulnerabletogrid-relatedproblemsbasedon2shorttermLOOPswhich10 wereconsideredtobegrid-related.ThiswouldplacetheplantinGroup"P3"withoutfurtheranalysis(Reference7,Table4).However,thelicenseestatedthatinthelast10yearsthesoutheasternFloridagridhasbeensignificantlystrengthenedbyimprovedrecoveryprocedures,additional500kVlines,andimprovedinterconnectionstogasturbinesinthegeneralarea.Table4ofRG1.155allowsexemptionfromthisautomatic"P3"categorizationofplantsexperiencingfrequentLOOPsifthesitehasprocedurestorecoveroffsitepowerfromareliablesourcewithinapproximately1/2hourfollowingagridfailure.FloridaPowerIILighthasgrid-wideoffsitepowerrestorationproceduresforsupplyingpowertotheSt.Luciesitefollowingagridfailure.Thegridcanbepoweredfromseveralsources,includingseveralgasturbinesitesinsouthernFlorida.Therefore,thelicenseeclaimsthattheSt.Luciesiteshouldnotbecategorizedasa"P3"sitebasedonthepastgridinstabilityproblems.WebelievethatsoutheasternFloridaisexposedtoseverehurricanesandthatthesitegeographiclimitationshampertheavailabilityofoffsitepowerfrommultiplesources.(St.Luciecannotgetpowerfromtheeastandessentiallycannotgetpowerfromthesouthsinceaseverestormorgridproblemislikelytoeffectallgeneratingsitessouthofthesite.)St.Lucieissusceptibletobothweather-related(ESW"5")yndgrid-relatedevents,therefore,itfallsintothe"P3"group.Sincethelicenseestatedthattheexistingprocedureswillbemodifiedtoincludecriteriaforshutdownoftheunitstwohourspriortothearrivalofhurricanes(16)consistentwiththeguidanceprovidedinNUHARC87-00,thesiteshouldbecategorizedas"P3."TReliabilitCoinuratio--ThelicenseestatedthattheassignmentoftheEDGtargetreliabilityof0.95issupportedbythedieseloperabilityreportstoINPO.Thesereportswerenotreviewed.AreviewoftheinformationinNSAC-108indicatesthattheEDGsatSt.LucieUnits1and2haveanaverageof41and60validdemandspercalendaryearandexperiencednofailurestostartintheyears1983,1984or1985.Thelicenseeexpectscontinuedhighdieselreliability11 becausetheEDGsarecontinuallyprelubedandwarmed,andstatesthataformalizedEDGpreventivemaintenanceprogramhasbeeneffectiveinmaintaininghighEDGreliability.Thelicensee'ssubmittalstatedthattheplantmeetsthecriteriaforanEDGreliabilitygoalof0.95.ThelicenseebelievesthatthepresentEDGreliabilityprogramissufficienttosatisfytheguidelinesofRegulatoryGuide1.155,Section1.2andNUMARC87-00,AppendixD.Thelicenseepresentedashortwrite-upontheprogram(18)andabriefdiscussionduringtheauditreview.Fromtheavailableinformation,wecannotdetermineiftheFPLprogram,whichisbasedonqualitycontrolmethods,satisfiestheaboveguidelines.ThelicenseestatedthatfollowingclosureoftheNRC/industryinitiativesonEDGreliability(theGenericSafetyIssueB-56)thenewguidancewillbereviewedandappropriateenhancementswillbemadetothecurrentreliabilityprogram.TheresultsofourreviewindicatethattheoffsitepowercharacteristicandtheEACconfigurationgroupingofthesiteare"P3"and"C,"respectively.UsingTable3-8ofNUNARC87-00,thesiterequiredcopingdurationwouldbefourhourswithanEDGtargetreliabilityof0.975,oreighthourswithanEDGtargetreliabilityof0.95.Thelicensee'scopinganalysiswasperformedfora4-hourSBOcopingduration.Mereviewedthelicensee'ssubmittalforacopingdurationofeighthoursasrequiredforanEDGtargetreliabilityof0.95.3.2AlternateAG(AAC)PowerSourceLicensee'sSubmittalThelicenseestatedthattheAACpowersourcefortheSt.LucieUnit1willbetheemergencyACpowersourcefromthenon-blackedoutunit(Unit2)whichmeetsthecriteriaspecifiedinAppendixBtoNUNRC87-00andtheassumptionsinSection2.3.1ofNUNRC87-00.TheAACpowersourceisavailablewithin10minutesoftheonsetoftheSBOeventbymanualoperationofcross-tiebreakersfromthecontrolroom.Eachof12 St.Lucie'stwounitshavetwodedicatedEDGs.UponthelossofoffsitepowerandfailureofUnit1EDGstooperate,eitheroneoftheUnit2EDGsiscapableofprovidingpowerforsafeshutdownofbothunitsforfourhours.ReviewofLicensee'sSubmittalExceptforthefollowingconcern,weagreewiththelicensee'sstatementthattheAACpowersource(siteEDGs)meetsthecriteriainAppendixBofNUNRC87-00:ParagraphB.9ofAppendixBstates,"....Atamulti-unitsite,exceptfor1/2Sharedor2/3emergencyACpowerconfiguration,anadjacentunit'sClass1EpowersourcemaybeusedasanAACpowersourcefortheblacked-outunitifitiscapableofpoweringtherequiredloadsatbothunits."TheguidanceontheuseofexistingEDGsasAACpowersourcesatmulti-unitsitesisdocumentedinRG1.155,Section3.3.5,NUHARC87-00,Section2.3.1(3)andfurtherdetailedunderquestion3.4andB.3inNUNRC87-00Supplementalguestions/AnswerswhichwasreviewedandendorsedbytheNRCstaff(16).TheSBOrulestatesthatatmulti-unitsiteswherethecombinationofEACpowersources'exceedstheminimumredundancyrequirementsforsafeshutdown(non-DBA)ofallunits,theremainingEACsourcesmaybeusedasAACsources'rovidedthattheymeettheapplicablerequirements.Therulestatementrequires'minimumredundancy.'hismeansthatinorderforanEOGtoqualifyasanAACsourcetheremustbeanEDGavailableintheNBOunitinadditiontothenumberofEOGsrequiredtomeettheminimumEOGredundancyrequirementforpoweringnormalsafeshutdownloadsfollowingaLOOPevent.Thus,theEOGsinatwo-unitsitewithtwodedicatedEDGsperunitwouldnotqualifyasAACsources.TwoEDGsperunitwouldmeetonlytheminimumredundancyrequirement,andthereisnoexcessEDG.13 However,therearesomeplantsatmulti-unitsiteswhichhaveEDGsthatjustmeettheminimumredundancybuteachEDGhassufficientcapacitytopowerallthenormalLOOPloadsoftheNBOunitandalsohassufficientexcesscapacitytopowertherequiredsafeshutdownloadsoftheSBOunit.Recognizingtheexistenceofthistypeofsituation,thestaffhasinterpretedthe'literal'xcessEDGredundancyrequirementoftheSBOruletoallowlargecapacityEDGstoqualifyasAACsource,providedotherapplicablerequirementsaremet.Inordertotakecreditforthisinterpretation,theNRCstaff'sbasicpositionhasbeen(17,19and20)that:'InoactionshouldbetakenthatwouldexacerbatethealreadydifficultsituationintheNBOunit.AnyactionsthatmakeoperatortasksmoredifficultsuchasloadswitchingordisablementofinformationreadoutsoralarmsinthecontrolroomarealsoconsideredtobeadegradationofnormalsafeshutdowncapabilityforLOOPintheNBOunit.And,2.excesscapacityoftheEDGbeingdesignatedasanAACsourceshouldnotbethecapacitymadeavailablebysheddingornotpoweringnormalsafeshutdownloadsintheNBOunit.Examplesofsuchloadsare:motordrivenauxiliaryfeedwaterpumps;heating,ventilationandairconditioning'loads;thepowersupplyoftheplantcomputer;oneormoresetsofredundantinstrumentation;etc.ThesheddingofsuchloadsconstitutesdegradationofthenormalsafeshutdowncapabilityoftheNBOunit.ItisnotintheinterestofsafetytoreducethecapabilitytohandlevariouseventualitiesinoneunitforthepurposeofmeetingtheSBOruleinanotherunit.EachunitmustmeettheSBOruleonitsownmeritswithoutreducinganotherunit'scapabilitytorespondtoitsownpotentialproblems.14 TheexcesscapacityoftheEDGintheNBOunitthatqualifiesitasanAACsourceis,therefore,'onlythatavailablecapacitywithinthenormalcontinuousratingbutabovetheEDGloadrepresentedbythecompletecontingentofsafetyrelatedandnon-safetyrelatedloadsnormallyexpectedtobeavailablefortheLOOPcondition.'uringthesiteauditreviewthelicenseestatedthateachoftheUnit2EDGshassufficientcapacitytopowertherequiredloadsatbothunits.Insupportofthisstatementthelicenseeprovidedthefollowingloadparametersrepresentingthehotstandbyrequiredloads(inkW):Unit22000hr.LOOPEOG~RatinLaa~dUnit1SBO~oi~2A39352B393519541954897897ThelicenseealsoprovidedabreakdownoftheloadsoneachEDG.Ourreviewoftheseloadsrevealsthat,thelicensee'sLOOPloadsdonotincludeloadssuchas:auxiliaryfeedwaterpump,residualheatremovalpump,reactorcoolantpumpoilliftpump,dieseloiltransferpump,instrumentaircompressoranddryer,boricacidmakeuppump,etc..Thelicenseealsodidnotconsidertheinstrumentair(IA)compressorandtheassociatedcoolinganddryingancillaryloadsintheSBOunit.Toconformtotheguidancestatedabove,theLOOPloadsatUnit2,excludingtheshort-termNOVloads,areestimatedat2802.5kWusingtheitemizedLOOPloadsinTable8.3-2oftheplantUFSAR(13).IfweweretoaddthecorrectedSBOloads(1133.5kW),whichincludesanIAcompressorandthesecondbatterychargerastheirneedsareindicatedbythelicensee,totheLOOPloads(2802.5kW),thenanEDGwithaminimum2000hourratingcapacityof3936kWwouldbeneededtoconformtotheaboveguidance.ThelicenseestatedthateachEDGatUnit2isratedat3935kWfor2000-houroperationperyear.15 Basedonthisevaluation,itappearsthattheeachEDGessentiallyhassufficientcapacitytosupplytheneededloadsintheNBOunitandtheselectedloadsintheSBOunit.However,sincenoexcesscapacityisavailable,thelicenseeneedstoverifythatnoadditionalloadsotherthanthoseincludedunderitem4inSection3.3.Additionally,thelicenseeneedstodemonstratebyatestthattheAACpowersourcecanpowertheshutdownbuseswithin10minutesoftheonsetofanSBO,inaccordancewithNUNRC87-00Section7.1.2andRG1.155,Section3.3.5.3.Duringthesiteauditreview,thelicenseestatedthatthistestwouldbeperformedaspartofthemodification.3.3StationBlackoutCopingCapabilityThelicenseedidnotprovideanyinformationregardingtheUnit1copingcapabilityinitssubmittaldatedApril17,1989(10).DuringthesiteauditreviewthelicenseestatedthatsincetheAACpowersourcewillbeavailablewithin10minutes,thecopingevaluationsforclass1Ebatterycapacity,compressedair,andcontainmentisolationneednotbeaddressedper10CFR50.63(c)(2).WeconsiderthistomeanthatfunctionsneededtocopeanSBOareavailableandadequatelypoweredfortherequiredduration.TheplantcopingcapabilitywithanSBOeventfortherequireddurationofeighthoursisassessedbasedonthefollowingresults:1.CondensateInventoryforDecayHeatRemovalLicensee'sSubmittalDuringthesiteauditreview,thelicenseestatedthatSt.Lucietechnicalspecificationsrequireaminimumcondensatestoragetank(CST)levelof116,000gallonsinUnit1and307,000gallonsinUnit2.ThelicenseestatedthatthisvolumeofwaterexceedsthequantityrequiredtocopewithanSBOof4-hourdurationandprovidedjustificationsfromanalysesperformedinsupportofthe16 plants'FSARs(12and13).Basedonthisinformation,thelicenseestatedthatUnit1needs-62,000gallonsofcondensatetoremovedecayheatduringa4-hourSBOevent(18).ReviewofLicensee'sSubmittalUsingNUNRC87-00,Section7.2.I,weestimatedthatStLucieUnit1wouldneed97,905gallonsofcondensatetoremovedecayheatduringan8-hourSBOevent.Thisestimateisbasedonamaximumreactorthermalcapacityof2,754HMt,orat1025oftheratedpower.Therefore,theminimumCSTlevelensuresadequatecondensatewaterforcopingwithanSBOwithadurationof8hoursforeachunit.TheexcessinventoryavailableintheCSTcanbeusedtoassistinSBOrecovery.2.ClasslEBatteryCapacityLicensee'sSubmittalDuringtheauditreview,licenseestatedthatsincetheAACisavailablewithin10minutesfromtheonsetofanSBOevent,thebatterycalculationsdonotneedtobeaddressedperguidance'rovidedinNUNRC87-00,Section7.1.2,and10CFRPart50.63(c)(2)ReviewofLicensee'sSubmittalThebatterychargersareavailableassoonastheAACsourceisonline,thusthelicenseewillhaveadequateDCpowertocopewithanSBOwithadurationofeighthours.ThelicenseestatedthattheyarenotsheddinganyDCloadsinthenon-blackedoutunitortheblacked-outunitthatcoulddegradethatunits'afeshutdowncapability.17 3.CompressedAirLicensee'sSubmittalDuringtheauditreview,thelicenseestatedthattheAACpowersourcewillbeavailablewithin10minutesandwillpoweranaircompressorwhichsupportstheairoperatedvalvesneededtocopewithanSBOevent.ReviewofLicensee'sSubmittalTheinstrumentairsystemwillbepoweredthroughouttheevent.Therefore,weagreewiththelicenseethatadequateinstrumentairisavailabletocopewithanSBO.4.EffectofLossofVentilationLicensee'sSubmittalDuringtheauditreview,thelicenseestatedthatthecontrolroomheating,ventilationandairconditioning(HVAC),andthefollowingventilationsystemswillbeoperatingduringanSBO:18 JL1liII I(I~4~VentilationFansUnit2.3.5.6.7.8.9.10.ContainmentFanCoolersIntakeCoolingMaterBuildingCoolingAuxiliaryBuildingCoolingFanECCSAreaExhaustFanReactorCavityCoolingFanReactorSupportCoolingFanElectricalEquipmentRoomSupplyFanElectricalEquipmentRoomExhaustFanElectricalEquipmentRoomRoofVentBatteryRoomExhaustFanI/2Fan2I/2I/2I/2I/2I/2I/2I/2I/2ReviewofLicensee'sSubmittalDuringtheauditreviewthelicenseestatedthathewasnotreadytodiscusstheeffectsoflossofventilationindetail.ThelicenseestatedthatadditionalinformationconcerningroomcoolingduringanSBOwillbeprovided.Additionalinformationhasyettobeprovided.OuranalysisofthecapacityoftheAACpowersourceindicatesthatthereisnoadditionalavailablecapacitytopowerventilationsystemsotherthanthosementionedabove.Therefore,ifthelicenseedeterminesthatadditionalventilationisneededtoensuretheoperabilityofSBOequipmentinotherareas,thelicenseeneedstoprovideaseparateAACpowersourcetosupplytheneededloads.6.ContainmentIsolationLicensee'sSubmittalDuringtheauditreview,thelicenseestatedthatallbuseswouldbeenergizedupontheavailabilityofAACpower.Thelicensee19 statedthatthiswouldallowforthenormalestablishmentandverificationofappropriatecontainmentintegrity.ReviewofLicensee'sSubmittalSinceallACandDCbusescanbeenergizedfromtheAACpowersource,weagreethatthelicenseecouldbeabletoestablishandverifyappropriatecontainmentintegrityduringanSBOevent.6.ReactorCoolantInventoryLicensee'sSubmittalDuringthesiteauditreviewthelicenseestatedthattheAACsourcepowersthenecessarymake-upsystemtomaintainadequatereactorcoolantsysteminventorytoensurethatthecoreiscooledfortherequiredcopingduration.ReviewofLicensee'sSubmittalThereactorcoolantsystem{RCS)losseswhichthelicenseeneedstoconsiderare:1.25gpmperpumplossesthroughreactorcoolantpumpsealsperNUMARCguidelines,2.maximumallowableRCSleakageperplanttechnicalspecifications.St.Luciehasfourreactorcoolantpumpswhichwillloseatotalof100gpmsealleakagefromthereactorcoolantsystem(RCS)..Thetechnicalspecificationmaximumallowableleakage(sumofidentifiedandunidentified)isestimatedtobe12gpm.Therefore,thelicenseeneedstoprovideamake-upsystemwithaminimumcapacityof112gpmtomaintaintheRCSinventoryprovided20 thatnoRCScooldownisinitiated.Thelicensee'sSBOloadsonlyconsiderpoweringonechargingpump;apositivedisplacementpumpwitha44gpmcapacity.ThelicenseedidnotprovideanyanalysistodemonstratethatthecorewillnotbeuncoveredduringanSBOeventwithonechargingpumpoperating.OuranalyticexperiencewithsimilarplantsindicatesthatanRCSleakageof112gpmwillnotresultincoreuncoveringduringan8-hoursSBOeventifa44gpmchargingpumpiskeptoperatingandtheRCScooldownisminimized.However,anauditmayberequiredtoensurethatthelicenseehasanapplicableevaluationwhichconfirmsourfinding.3.4ProposedProceduresandTrainingLicensee'sSubmittalThelicenseestated(10)thatthestationblackoutandotherapplicableprocedureswillberevised.Thelicenseeadded(18)thatFPLproceduresmeetorexceedNUNRC87-00guidelines,however,siteprocedureswillbemodifiedandrevisedtoinclude:1.procedurestoelectricallycross-connectunitsin10minutesfromthecontrolroomandtomitigatetheeffectsofaunitblackout2.procedurestocommenceunitshutdown2hourspriorstotheprojectedonsetofthehurricaneforcewindsatthesite.ThelicenseestatedthataprocedurewhichwillallowtheoperatorstouseanyoneoffourEOGstosafelyshutdownandmaintainbothnuclearunitsinhotstandbyconditionsforfourhourswillbedeveloped(10).ThelicenseestatedthatprocedurechangeswillbecompletedwithinoneyearofthenotificationfromtheNRCstaffper10CFR50.63(c)(3).21 Thisimplementationiscurrentlyplannedtobecompletedbyfourthquarterof1991.Thelicenseestatedthatexistingplantpoliciesandguidelinesfortrainingwillbeuseduponissuanceofnewandrevisedprocedures.ThelicenseealsostatedthatthesepolicieswillensurethatoperatorsareadequatelypreparedtocopewithSBOevents.ReviewofLicensee'sSubmittalThereviewteamdidnotexaminetheaffectedproceduresortraining.WeconsidertheseproceduresasplantspecificactionsconcerningtherequiredactivitiestocopewithanSBO.Itisthelicensee'sresponsibilitytoreviseandimplementtheseprocedures,asneeded,tomitigateanSBOeventandtoassurethattheseproceduresarecompleteandcorrectandthattheassociatedtrainingneedsarecarriedoutaccordingly.3.5ProposedModificationsLicensee'sSubmittalTheproposedmodificationentailsaddingclasslE4.16kVbreakersandbusworktotietheexistingsafety-relatedswingbuses(1ABand2AB)of.thetwounits.(SeeFigure1)ThelicenseestatedthatsinceeachswingbusiscapableofreceivingpowerfromeitheroftheEDGsinthatunit,atleastoneswingbusisalwaysassuredasourceofpower.Thelicenseestatedthatasafetybusontheblackedoutunitcouldthenbereenergizedviatheproposedcross-tiewithintenminutesfromthecontrolroom.Thelicenseestatedthatthemodificationandassociatedproceduralchangesarecurrentlyscheduledforthefourthquarterof1991.22 ReviewofLicensee'sSubmittalThelicenseestatedthatthisdesignchangewillbeimplementedinaccordancewiththeapplicabledesignandlicensingrequirementstocomplywiththeguidanceofRG1.155andNUNRC87-00includingtherevisedguidance(16).ThisdesignchangewillsignificantlyimprovethereliabilityofthesiteACpowersystem.3.6gualityAssuranceandTechnicalSpecificationsatssranceThelicenseestates(18)that:"PualityAssurance(gA)guidanceforSt.LuciestationblackoutmodificationswillbedictatedbylOCFR50AppendixBrequirementsunderthecurrentgAprogramatSt.Lucie.ThismeetsorexceedscriteriainRegulatoryGuideI.155."Basedonouraudit,itappearsthatallequipmentnecessarytocopewithanSBOeventiscoveredbyagAprogramthatisconsistentwiththeguidanceofAppendicesAandBofRG1.155.TechnicalSecificaioThelicenseedidnotidentifyanychangestocurrenttechnicalspecificationfortheinvolvedSBOequipment.Ourreviewofthelicensee'sapproachindicatesthattheequipmentnecessarytocopewithanSBO(EDGs,AFH,CST,batteries,etc.)isalreadycoveredbytechnicalspecification.23

4.0CONCLUSION

SBasedonourreviewofthelicensee'ssubmittalandtherelateds4pportingdocumentsanddiscussionsduringasiteauditfortheSt.LucieUnit1wefindthatthesubmittalconformstotherequirementsoftheSBOruleandtheguidanceofRG1.155withthefollowingexceptions:1.ProposedStationBlackoutDurationa0ffsiteowerDesinCharacterisicGrTheSt.Luciesitehasexperiencedtwoshort-termgrid-relatedLOOPsinthelast20years,andbasedonitsgeographicalpositionNRCdataitiscategorizedasESWgroup"5".Eitherthegrid-relatedLOOPfrequencyofgreaterthanonein20ortheESWgroup"5"inconjunctionwiththeplant'spre-hurricaneshutdownprocedures,wouldplacetheplantingroup"P3."ThelicenseeclaimsthatthesiteisinESWgroup"4"andrequestsanexemptionfromthegridrelatedLOOPfrequencycriterionbasedongridimprovements.However,thepreponderanceofevidenceindicatesthattheplantisingroup"P3"(seeSection3.1).b.merencACPowerConfiurationEACGrouThelicenseeclaimsthattheEACconfigurationis"A."OurreviewindicatesthatitshouldbeclassifiedasanEACgroup"C."EachEGGdoesnothavesufficientcapacitytosupportalltheequipmentrequiredtobeoperationalafteraLOOPatbothunitsconsistentwiththeguidanceprovidedinNUNRC87-00Supplementalguestions/Answers.c.IndeendenceofOffsitePowerIGruThelicenseeclaimsthatSt.Lucieshouldbeconsideredas"I2"grouping.Forthesitetobeconsideredas"I2"thelicensee24 needstoverifythateachoftheunitauxiliaryorstart-uptransformershassufficientcapacitytosupportthenormalloadsondivisionofbusesinoneunitandthesafeshutdownloadsononedivisionofemergencybusesinotherunit.Otherwise,an"13"classificationshouldbeconsidered.However,the"I"classificationdoesnotchangethedeterminationof"P3*."d.SBOCoinDurationandEDGTaretReliabilitBasedonitemsaandb,therequiredcopingdurationofStLucieUnit1withanEDGtargetreliabilityof0.95iseighthours..However,thelicenseecanclaimarequiredcopingdurationoffourhoursifitselectsanEDGtargetreliabilityof0.975.2.AlternateAGPowerSourceThelicenseeneedstodemonstrate,byatest,thattheAACpowersourcecanpowertheshutdownbuseswithin10minutesoftheonsetofanSBO,inaccordancewithRG1.155,Section3.3.5.3.3.EmergencyDieselGeneratorReliabilityProgramThelicensee'ssubmittaldoesnotdocumenttheconformanceoftheplant'sEDGreliabilityprogramwiththeguidelinesofRegulatoryGuide1.155,Section1.2andNUMARC87-00,AppendixD.DuringthesiteauditreviewthelicenseestatedthatthepresentEDGreliabilityprogramissufficienttosatisfytheaboveguidance.Thelicenseestated,however,thatareliabilityprogramwillbeevaluatedagainsttheaboveguidanceandwillbeadjustedtomeettheintent.4.EffectsofLossofVentilation'helicenseehasnotcompletedtheevaluationtodeterminetheeffectsoflossofventilationduringanSBOevent.Ouranalysis25 oftheproposedAACpowersourceindicatesthatitdoesnothaveadditionalcapacitytosupportventilationsystemsotherthanthosementionedinSection3.3.Therefore,ifthelicenseedeterminesthatadditionalventilationisneededtoensuretheoperabilityofSBOequipmentinotherareas,thelicenseeneedstoprovideaseparateAACpowersourcetosupplytheneededloads.26 seea~~

5.0REFERENCES

1.TheOfficeofFederalRegister,"CodeofFederalRegulationsTitle10Part50.63,"10CFR50.63,January1,1989.2.U.S.NuclearRegulatoryCommission,"EvaluationofStationBlackoutAccidentsatNuclearPowerPlants-TechnicalFindingsRelatedtoUnresolvedSafetyIssueA-44,"NUREG-1032,Baranowsky,P.M.,June1988.3.U.S.NuclearRegulatoryCommission,"CollectionandEvaluationofCompleteandPartialLossesofOffsitePoweratNuclearPowerPlants,"NUREG/CR-3992,February1985.4.U.S.NuclearRegulatoryCommission',"ReliabilityofEmergencyACPowerSystematNuclearPowerPlants,"NUREG/CR-2989,July1983.5.U.S.NuclearRegulatoryCommission,"EmergencyDieselGeneratorOperatingExperience,1981-1983,"NUREG/CR-4347,December1985.6.U.S.NuclearRegulatoryCommission,"StationBlackoutAccidentAnalyses(PartofNRCTaskActionPlanA-44),"NUREG/CR-3226,Hay1983.7.U.S.NuclearRegulatoryCommissionOfficeofNuclearRegulatoryResearch,"RegulatoryGuide1.155StationBlackout,"August1988.8.NuclearManagementandResourcesCouncil,Inc.,"GuidelinesandTechnicalBasesforNUMARCInitiativesAddressingStationBlackoutatLightMaterReactors,"NUNARC87-00,November1987.9.NuclearSafetyAnalysisCenter,"TheReliabilityofEmergencyDieselGeneratorsatU.S.NuclearPowerPlants,"NSAC-108,Myckoff,H.,September1986.27 e'~rL, 10.Conway,W.F.,lettertotheU.S.NuclearRegulatoryCommission,"St.LucieUnits1and2,Oockets50-335and50-389,InformationtoResolveStationBlackout,"FPLL-89-144,10CFR50.63,April17,198911.Thadani,A.C.,LettertoW.H.RasinofNUMARC,"ApprovalofNUMARCDocumentsonStationBlackout(TAC-40577),"datedOctober7,1988.12.FloridaPower5Light,"FinalSafetyAnalysisReport-St.LucieUnit1"13.FloridaPower8Light,"FinalSafetyAnalysisReport-St.LucieUnit2"14.U.S.NuclearRegulatoryCommission,"ShutdownDecayHeatRemovalAnalysisofaWestinghouse3-LoopPressurizedWaterReactor-CaseStudy,"NUREG/CR-4762,dated1986.'5.Dames&Moore,"UpdatedReport-ProbabilisticHurricaneAnalysesMethodologyDevelopment-TurkeyPointandSt.LucieNuclearPowerPlantsforFloridaPower5LightCompany",January198916.Thadani,A.C.,lettertoA.MarionofNUMARC,"PubliclyNoticedMeetingDecember27,1989,"datedJanuary3,1990,(Confirming"NUMARC87-00Supplementalguestions/Answers,"December27,1989).17.Rosa,F.,MemorandumtoDocketconcerningBeaverValleyUnits1and2,"MeetingSummary-MeetingofFebruary22,1990,onStationBlackoutIssues(TAC68510/68511),"DocketNos.50-334and50-412,dated.March6,1990.18.Sager,D.A.,lettertotheU.S.NuclearRegulatoryCommission,"St.LucieUnits1and2,Oockets50-335and50-389,InformationtoResolveStationBlackout,"FPLL-90-58,10CFR50.63,datedMarch7,1990.19.Tam,P.S.,Memorandumfor,"DailyHighlight-ForthcomingMeetingwithNUHARConStationBlackout(SBO)Issues(TAC40577),"datedApril25,1990(ProvidingaDraftStaffPositionRegardingUseofEmergencyAC28 PowerSources(EDGs)asAlternateAC(AAC)PowerSources,datedApril24,1990).20.Russell,M.T.,lettertoM.RasinofNUNRC,"StationBlackout,"datedJune6,1990.29