ML17213A498

Technical Evaluation of Adequacy of Station Electric Distribution Sys Voltages for St Lucie Nuclear Power Plant, Unit 1.

ML17213A498
Person / Time
Site:	Saint Lucie
Issue date:	10/05/1981
From:	SELAN J C LAWRENCE LIVERMORE NATIONAL LABORATORY
To:	Office of Nuclear Reactor Regulation
Shared Package
ML17213A497	List: ML17213A496 ML17213A498
References
CON-FIN-A-0250, CON-FIN-A-250 UCID-19110, NUDOCS 8209280487
Download: ML17213A498 (14)

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• ,'~,*=~lPTECHNICALEVALUATIONOFTHEADEQUACY.OFSTATIONELECTRICDISTRIBUTIONSYSTEMVOLTAGES:"':..FORTHEST;LUCIENUCLEARPOWERPLANT,UNITl-':.'.'"~'...-'<<'.,'e1ectedIssuesProgram,-,'."JakesC.Selan'"~"\PJ'DocketNo.50-335):..'-~4YI-~~,e.i.'<<\~~P~'"'I~C.~~I-A7ThisGaninformafrep'ortintendedpriman1yforinterrialorlimitedexteinaldlitribuihn':,'.<<j'>pr~gg~">"~>~~>"<<rr)>>gee"-"~j'.,Theopinionsandeondusionsstatedarethoseoftheauthoiandmayormaynotbethose;",.:"';~5~~y~~:",.-~~j:-.'ja'.~~+"<'g~~~4<<'TMsworkwiisupportedbytheUnitedStatesNudearRegulatoryCommissionunder@";.~".~>",.~."-'.g,,aMemoranduniofUnderstandingwiththeUnitedStatesDepartmentofEnergy.":;,'~,.'-",4:g'-'".",-'r;<+.8209280487820902PDRADOCK05000335...,'*~,PPDR 0"l Thisdocnmentwaspreparedasaniccouiitofworksponsoredbyanagency'ftheUnitedStatesGovernment.Neither.'theUnitedStatesGovernmentnorinyagencythereof,noranyoftheiremployees,makesanywarranty,expressed.*'orimplied,orassumesanyleg~iliabilityorresponsibilityfortheaccuracy,'ompleteness,"orusefulnessofanyinformation,apparatus,product,'rprocessdisclosed,orrepresentsthatitsusewouldnotinfringeprivatelyowned:rights.Referencehereintoanyspeciliccommercialproduct',procesi;orservicebytradename,trademark;manufac-'urer,orotherIwise,doesnotnecessarilyconstituteorimplyitsendorsement,recommendation,orfavoringbytheUnitedStatesGovernmentoranyagencythereof.TheviewsandopinionsofauthorsexpressedhereindonotnecessarilystateorrellectthoseoftbeUnitedStatesGovernmentoranyagencythereof;..-'-.','-I~I)~O'J'I)II)Ih0'<A'%I~~II~'I~~')I*~~~c~~1I~'trIr,',~~i11A)I,).~.).=I~~I~,\Itr."I=l'.~I't~>'."',~Ig',,~,~~)f.*~II'-~',.'~'.".;,".,.~>'.'..'..-",."Arnilablefrom:;)VnrlonatTechnicallnfonnstloiiService',US.DepartmentofCornrncre'e-:..q~').,'.'.'.'.'-'.~'.'..(.';.-~":;;.5285PortRoyalRoad"'.Sprin'gAeld,VA2216l-~$5,00-'ercopy'"-(Mlerotiehe$X50)',r'l,'..-~.:~".'-'~".'."-..'<<,.'~'r~uI) a'h1"'<o~4'4'cfear~'avidI4<<t',,i'~s'>>'w'-~m'ws"st%.a"'t,'c~)i's4't~'>~aaa~5iw~rs.ivS~*'aABSTRACTThisreportdocumentsthetechnicalevaluationoftheadequacyofthestationelectric'istributionsystemvoltagesfortheSt.LucieNuclearPowerPlant,Unit.1..Theevaluationistodetermineif,theonsitedistributionsystem,inconjunctionwiththeoffsitepower.sources,hassufficientcapacitytoautomaticallystartandoperateallClasslEloadswithintheequipmentvoltageratingsundercertainconditionsestablishedbytheNuclearRegulatoryCommission.ThevoltageanalysissubmirtedhasadequatelydemonstratedthecapacityandcapabilityoftheelectricaldistributionsystemtosupplyadequatevoltagetotheClass1Eequipmentunderworstcaseoperatingconditions.FOREWORDThisreportissuppliedaspartoftheSelectedElectrical,Instrumentation,andControlSystemsIssuesProgrambeingconductedfortheU.S.NuclearRegulatoryCommission,'fficeofNuclearReactorRegulation,DivisionofOperatingReactors,byLawrenceLivermoreNational'aboratory.TheU.S.NuclearRegulatoryCommissionfundedtheworkundertheauthorizationentitled"Electrical,InstrumentationandControlSystemSupport",BGR201904031,FINA-0250.-111-TABLEOFCONTENTS~pael.INTRODUCTION..~...o~~..~~~.12.DESIGNBASISCRITERIAo..o~.~~.~~~13.SYSTEHDESCRIPTION......~.~...~24ANALYSIS4.14.24'.14'.243AnalysisConditions.AnalysisResultsOvervoltageUndervoltageAnalysisVerification~~~4~4~4~4~465~EVALUATION66~CONCLUSION7REFERENCES~~~~~~~~~~~~~~~i8ILLUSTRATIONSFIGURE1St.Lucie-Unit1ElectricalOne-LineDiagram~~~~Pae~~3TABLE1St.Lucie-Unit1Class1EEquipmentVoltageRatings'andAnalyzedHorstCaseTerminalVoltages~~.~..~~5 TECHNICALEVALUATIONOFTHEADEQUACYOFSTATIONELECTRICDISTRIBUTIONSYSTEMVOLTAGESFORTHEST.LUCIENUCLEARPOWERPLANTUNIT1(DocketNo.50-335)JamesC.SelanLawrenceLivermoreNationalLaboratory,Nevada1~INTRODUCTIONTheNuclearRegulatoryCommission(NRC)byaletterdatedAugust8,1979[Ref.1],expandeditsgenericreviewoftheadequacyofthestationelectricdistributionsystemsforalloperatingnuclearpowerfacilities.Thisreviewistodetermineiftheonsitedistributionsystem,inconjunctionwiththeoffsitepowersources,hassufficientcapacityandcapabilitytoautomaticallystartandoperateallrequiredsafetyloadswithintheequipmentvoltageratings.Inaddition,theNRCrequestedeachlicenseetofollowsuggestedguidelinesandtomeetcertainrequirementsintheanalysis.TheserequirementsaredetailedinSection5ofthisreport.BylettersdatedNovember9,1979[Ref.2],September12,1980[Ref.3],February10,1981[Ref.4],andJuLy23,1981[Ref.5],FloridaPower&LightCompany(FPL),thelicensee,submittedtheiranalysisandconclusionregardingtheadequacyoftheelectricaldistributionsystem'svoltagesatSt.Lucie,Unit1.Thepurposeofthisreportistoevaluatethelicensee'ssubmittalwithrespecttotheNRCcriteriaandpresentthereviewer'sconclusionontheadequacyofthestationelectricdistributionsystemstomaintainthevoltagewithinthedesignlimitsoftherequiredClass1Eequipmentfortheworstcasestartingandloadconditions'.DESIGNBASISCRITERIAThedesignbasiscriteriathatwereappliedindeterminingtheadequacyofstationelectricdistributionsystemvoltagestostartandoperateallrequiredsafetyloadswithintheirrequiredvoltageratingsareasfollows:

(1)GeneralDesignCriterion17(GDC17),"ElectricPowerSystems,"ofAppendixA,"GeneralDesignCriteriaforNuclearPowerPlants,"intheCodeofFederalRegulations,Title10,Part50(10CFR50)[Ref.6]~(2)GeneralDesignCriterion13(GDC13),"InstrumentationandControl,"ofAppendixA,"GeneralDesignCriteriaforNuclearPowerPlants,"intheCodeofFederalReulations,Title10,Part50(10CFR50)Ref.6(3)ANSIC84.1-1977,"VoltageRatingsforElectricPowerSystemsandEquipment"[Ref.7].(4)IEEEStd308-1974,"Class1EPowerSystemsforNuclearPowerGeneratingStations"[Ref.8]~(5)"GuidelinesforVoltageDropCalculations,"Enclosure2,toNRCletterdatedAugust8,1979[Ref.1].3.SYSTEMDESCRIPTIONAnelectricalone-linediagramofSt.Lucie,Unit1,isshowninFigure1.Theelectricaldistributionsystemisdesignedsuchthatduringnormalstartupandshutdownconditions,theauxiliaryloadsaresuppliedbythestartuptransformer.Whentheunitisabove170MWepoweroutput,theauxiliaryloadsaresuppliedbytheunitauxiliarytransformer.Thetwostartuptransformersaresuppliedfroma240KVswitchyardwheretheoutputoftheunitgeneratorisconnectedthroughamaintransformerbank.Thetwostartuptransformershavenoelectricalintertieconnectionsbetweenthemwitheachtransformersupplyingitsowntrainofauxiliaryloads.Aunittriporasafetyinjectionsignal(SIS)willinitiateautomatictransferoftheonsitedistributonsystemfromtheunitauxiliarytransformertothes'tartuptransformer.Boththestartuptransformersandunitauxiliarytrans-formershavetwosecondarywindings,withoneat6.9KVandthesecondat4160volts.Therearethree4160-voltandthree480-voltClass1Ebuses.TheClass1Eequipmentisprotectedfromundervoltageconditionsbyanundervoltagerelaylocatedoneach4160-voltClass'lEbus.Theinversetimerelayhasavoltagesetpointof88.34Xof4160volts(3675volts)withatimedialsettingof1.Therelaywillactuateat79.5Xof4160voltsin'pproximately3seconds.=Thevoltagesetpointatthe4160-voltlevelisequiva-lentto83%of480voltsattheClass1E480-voltmotorcontrolcenterbuses.Thelicenseestatesthatadesignmodificationisplannedtoaddundervoltagerelaysonthe480-voltClass1Ebuses[Ref.2].Thelicenseehasnotprovidedanyfurtherdesigninformationontheplannedmodification.

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4~ANALYSIS4.1ANALYSISCONDITIONSFPLanalyzedtheonsitedistributionsystemvoltageswiththestartuptransformerasthesupplyingsourceunderminimumandmaximumexpectedgridvoltagesof230KVand244KV,respectively.Inconjunctionwiththeaboveconditions,threeloadingcaseswereanalyzedtodeterminethevoltageattheterminalsoftheClasslEequipment.InCase1,thenormalrunningloadsweretransferredtothestartuptransformerfollowingaunittripfromfullloadcoincidentwithaminimumexpectedgridvoltage.TheloadingconditionsofCase2arethesameasCase1,butwiththeadditionofloadsassociatedwithanaccident.FinallyinCase3,theloadingconditionswerethesameasCase1exceptthegridwasatthemaximumexpectedvalue.Inadditiontotheaboveconditions,thefollowingassumptionswerealsomade:(1)Normalloadsusedweremeasuredvalueswiththep~antatfullload.(2)Powerfactorofrunningloadswasassumedas0.85.(3)HeasurednormalrunningloadsincludedseveralClasslEloads.(4)Startingpowerfactorforthe4KVmotorswasassumedas0.22.Startingcurrentwastakenfromnameplatedata.(5)Startingpowerfactorforthe480-voltmotoroperatedvalveswasassumedtobe0.60.Thestartingcurrentwastakenfromplantstartuptestdata.(6)Allcurrentswereassumedtoremainconstant.4.2ANALYSISRESULTSTheworstcaseClasslEequipmentterminalvoltagesfromtheanalysessubmittedoccurunderthefollowingconditions:Normalrunningloadsbeingsupplied.bythestartuptransformer(unittripwithloadtransfertothestartuptransformer)andgridatthemaximumexpectedvoltageof244KV.4.2'UndervoltaeUnittripfromfullloadwithtransferofthenormalrunningloadstothestartuptransformerconcurrentwithanaccidentconditionandthegridattheminimumexpectedvoltage,of230KV.TheaboveworstcaseClass1EequipmentterminalvoltagesareshowninTablel.

TABLE1ST.LUCIE-UNIT1CLASSlEEQUIPMENTVOLTAGERATINGSANDANALYZEDWORSTCASETERMINALVOLTAGES(inXofEquipmentNominalVoltageRating)MinimumRatedAnalyzedRatedAnalyzedEuipmentNominalVoltageRating(100X)SteadyStateSteady-StateTransientMotors4000StartOperate1101065759099.493~5460(')StartOperate110104.3759092.982Starters(PickupDropoutOperate12062'(c)11079'(c)81.18589OtherEquipment(d)(a)460-voltmotorscanoperateat75Xterminalvoltageforoneminutewithoutdamage.Also,460-voltMOV'.scanoperateindefinitelyat80Xterminalvoltage.(b)Motorcontrolcentercontactorsaresuppliedfrom480/120-volttransformers.Startersizes1-2and3-4aresuppliedby50VAand500VAsizetransformers,respectively.(c)Thesevaluesobtainedfromtestsperformed.(d)ClasslEinstrumentsarefedfrominverters.

4~3ANALYSISVERIFICATIONFPLobtainedtestdatabyusingstandardplanttestmethodologies'hisincludedusingvoltmeterstomeasurethesecondaryvoltagesofthepotentialtransformersforthe4160-voltswitchgearand480-voltloadcenters.Thebusamperesandthe480-voltMCCvoltageswerereadfromthecabinet'spanelboardmeters.Thereadingstakenwereonaperphasebasis.Thesereadingswerethenaveragedandtheirrespectivetransformerratioswereusedtocalculateactualbusvoltagesandamperes.Theverificationresultsshowsthattheanalyticalvalueswerewithin2Xoftheactualplantdataobtained[Ref.4).5~EVALUATIONTheNRCgenericletter[Ref.1}statedseveralrequirementsthattheplantmustmeetinthevoltageanalysis.Theserequirementsandanevaluationofthelicensee'ssubmittalsareasfollows:(1)Withtheminimumexpectedgridvoltageandmaximumloadcondition,eachoffsitesourceanddistributionsystemconnectionmustbecapableofstartingandcontinuouslyoperatingallClasslEequipmentwithintheequipment'svoltageratings.ThevoltageanalysisresultssubmittedbyFPLdemonstratethattheoffsitesources,incon)unctionwiththeonsitedistributionsystem,havethecapacityandcapabilitytoautomaticallystartandcontinuouslyoperatetheClasslEequipmentwiththedesignratingsfortheworstcaseconditions.(2)Withthemaximumexpectedoffsitegridvoltageandminimumloadcondition,eachoffsitesourceanddistributionsystemconnectionmustbecapableofcontinuouslyoperatingtherequiredClasslEequipmentwithoutexceedingtheequip-ment'svoltageratings.Thevoltageanalysisresultssubmitted,byFPLdemonstratethatthe:Class1Eequipmentuppervoltagedesignratingwillnotbeexceeded.(3)Theanalysismustshowthattherewillbenospurioussepara-tionfromtheoffsitepowersourcetotheClass1EbusesbythevoltageprotectionrelayswhenthegridiswithinthenormalexpectedlimitsandtheloadingconditionsestablishedbytheNRCarebeingmet.

~.~LLNLwillverifyinaseparatereport(TACNo.10052)thattherequirementsofthispositionaremet.FinaldesignandTechnicalSpecificationsareforthcoming.FPLdidnotsubmitanalyticaldataonstartingalargenon-Class1EloadaftertheClass1EbusesOrefullyloaded.Thelicenseestatesthatstartingalargenon-ClasslEloadwouldactuatetheunder-voltageprotectionrelayundertheworstcasecondition.Thelargestnon-Class1Emotoristhecondensate.pumpwhichwouldbenormallyoperating.Thepumpwouldhavetobemanuallytripped.Thelicenseestatesthatananalysisoftheplant'sconditionwouldbemadebeforeanattemptedrestartofthepump.FPLdidnotsubmitanywrittenplantproceduresaddressingthepumprestart.(4)Testresultsarerequiredtoverifythevoltageanalysescalculationssubmitted.FPLverifiedtheirvoltageanalysisbytestandthepercenterrordifferenceof2Xconfirmtheanalyticalresultsareacceptable.(5)Reviewtheplant'selectricalpowersystemstodetermineifanyeventsorconditionscouldresultinthesimultaneouslossofbothoffsitecircuitstotheonsitedistributionsystem.(compliancewithGDC17.)FPLreviewedtheelectricpowersystemsandfoundthatnosingleeventorconditioncouldresultinthesimultaneousorconsequentiallossofbothrequiredcircuitstotheonsitedistributionsystem,thusnoviolationofGDC17exists.6~CONCLUSIONSBasedontheinformationprovidedbyFloridaPowerandLightCompanyonSt.Lucie,Unit1'selectricaldistributionsystem,itisconcludedthat:(1)Voltageswithinthedesignratingsofthe.Class1Eequipmentaresuppliedfromtheoffsitesourcesunderworstcasecondi-tions.(2)Theverificationtestperformedverifiestheanalysisresults.(3)AseparatereportwillbemadebyLLNL(TACNo.10052-DegradedGrid)toverifythatspurioustripswillnotoccurduringvoltagetransientsuponfinaldesignandTechnicalSpecificationsubmittal.,fortheproposedundervoltageprotectionscheme.

(4),FPLhasdeterminedthatnopotentialforeitherasimul-taneousorconsequentiallossoftheoffsitesourcesexists.(5)Addtionaldetailsoftheplantproceduresforassessingplantconditionspriortotherestartofthecondensatepumpshouldbesubmitted.REFERENCES1.NRCletter(W.Gammill)toallPowerReactorLicensees,datedAugust8,1979.2.FPLletter(R.E.Uhrig)toNRC(W.Gammill),datedNovember9,1979.3.FPLletter(R.E.Uhrig)toNRC(D.G.Eisenhut),datedSeptember12,1980.4.FPLletter(R.E.Uhrig)toNRC(D.G.Eisenhut),datedFebruary10,1981.5.FPLletter(R.E.Uhrig)toNRC(D.G.Eisenhut),datedJuly23,1981.6.CodeofFederalReulations,Title10,Part50(10CFR50),GeneralDesignCriterion13and17ofAppendixAforNuclearPowerPlants.7.ANSI'C84.1-1977,"VoltageRatingsforElectricPowerSystemsandEquipment."8.IEEESTD.308-1971,"Class1EPowerSystemforNuclearPowerGeneratingStations."

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