ML17262A174

Forwards Rev 1 to Design Analysis EWR 4525-1, Fault Current Analysis of Power Distribution Sys & Rev 1 to Design Analysis EWR 4525-2, Adequacy of Electric Sys.... NRC Will Be Notified of Util Intended Corrective Action by 901030

ML17262A174
Person / Time
Site:	Ginna
Issue date:	09/20/1990
From:	MECREDY R C ROCHESTER GAS & ELECTRIC CORP.
To:	JOHNSON A R Office of Nuclear Reactor Regulation
Shared Package
ML17262A175	List: ML17262A174 ML17262A176 ML17262A177 ML17262A178
References
NUDOCS 9010050242
Download: ML17262A174 (7)

Text

ACCELERATEDDISRIBUTIONDEMONSTTIONSYSTEMREGULATORYINFORMATIONDISTRIBUTIONSYSTEM(RIDS)ACCESSIONNBR:9010050242DOC.DATE:90/09/20NOTARIZED:NOFACIL:50-244RobertEmmetGinnaNuclearPlant,Unit1,RochesterGAUTH.NAMEAUTHORAFFILIATIONMECREDY,R.C.RochesterGas6ElectricCorp.RECIP.NAMERECIPIENTAFFILIATIONJOHNSON,A.R.ProjectDirectorateI-3DOCKET05000244

SUBJECT:

ForwardsDesignAnalysis4525-1,"FaultCurrentAnalysisforPowerDistributionSys,"Rev1&DesignAnalysis4525-2.DISTRIBUTIONCODE:AOOIDCOPIESRECEIVED:LTR$ENCL$SIZE:TITLE:ORSubmittal:GeneralDistributionNOTES:LicenseExpdateinaccordancewith10CFR2,2.109(9/19/72).05000244RECIPIENTIDCODE/NAMEPDl-3LAJOHNSON,AINTERNAL:NRR/DET/ECMB9HNRR/DST8E2NRR/DST/SICB7ENUDOCS-ABSTRACTOGC/HDS2RES/DSIR/EIBEXTERNAL:NRCPDRCOPIESLTTRENCL11221111111'101111RECIPIENTIDCODE/NAMEPD1-3PDNRR/DOEA/OTSB11NRR/DST/SELB8DNRR/DST/SRXB8EGFILEOlNSICCOPIESLTTRENCL11111111101111NOTETOALL"RIDS"RECIPIENTS:PLEASEHELPUSTOREDUCEiVASK!CONTACTTHEDOCUMENTCONTROLDESK,ROOMPl-37(EXT.20079)TOELIMINATEYOURNAMEFROMDISTRIBUTIONLISTSFORDOCUMENTSYOUDON'TNEED!TOTALNUMBEROFCOPIESREQUIRED:LTTR17ENCL15

\f$a IIIIIIIIIII/IIIIIIIIIIII~AirOall*///IjI//Ij/I//III/IIIg!p',ROCHESTERGASANDELECTRICCORPORATIONo89EASTAVENUE,ROCHESTERN.Y.14649-0001ROBERTC.MECREDYVicePresidentCinnaNuctearProductionSeptember20,1990TEt.EPHONEArtEAcooE7re546.2700U.S.NuclearRegulatoryCommissionDocumentControlDeskAttn:AllenR.JohnsonProjectDirectorateI-3Washington,D.C.20555

Subject:

OffsitePowerSystemAnalysesR.E.GinnaNuclearPowerPlantDocketNo.50-244

DearMr.Johnson:

Peryourrequest,weareenclosingcopiesofDesignAnalysis4525-1"FaultCurrentAnalysisofPowerDistributionSystem"Rev1andDesignAnalysis4525-2"AdequacyofElectricSystemVoltages"Rev1foryourreview.Theseanalysesquantifytheeffectsassociatedwiththerecentlycompletedoffsitepowerreconfiguration(EWR'4525).EWR4525modifiedtheoffsitepowersystemsuchthattherewouldbeadedicated34.5/4.16kVtransformerassociatedwitheachofthetwoindependentoffsitetransmissionlines.Station204energizestransformer12AwhichisnowthenormalsourceofpowerforBus12AandsafetytrainAwhileStation13Aenergizestransformer12BwhichisnowthenormalsourceofpowerforBus12BandsafetytrainB(seefigure1).Thisnormalconfigurationisreferredtoasthe50/50modesinceeachindependentoffsitepowersourcesupplies1/2oftherequiredoffsitepower.Theoperatorsstillhavetheabilitytoputtheoffsitepowersystemineitherthe100/0mode(Transformer12Bsuppliesalloffsitepower)orthe0/100mode(Transformer12Asuppliesalloftheoffsitepower).ThenormalconfigurationpriortoEWR4525wastohavealloffsitepowersuppliedbytransformer12A.EWR4525hassignificantlyreducedthelikelihoodofasimultaneouslossofoffsitepowertobothsafetytrainsandhasimprovedsystemperformancesincetheelectricalloadisnownormallydividedbetweentwotransformers.TheprimaryobjectiveofDesignAnalysis4525-2istodemonstratethatthereconfiguredoffsitepowersupplywillbecapableofmaintainingadequatevoltagesforallrequiredoperatingconditions.Theresultsindicatedthatbothoffsitesourcesr5'ot00502429005'20PDR4DOCK05000244PPDCgooI Il'IF"~A,4'3 (circuit751fromStation204&767fromStation13A)arecapableofprovidingadequatevoltagesforallrequiredfunctions.Twospecialcasesarediscussedbelowwhichrepresentthelimitingcases:1.ThecomputersimulationsindicatedthatbothoffsitesourcesmayhavedifficultyinmaintainingadequatevoltagesduringthestartupofaReactorCoolantPump(RCP)forthespecialcasewhentheoffsitegridvoltagewasatitsminimumvalue(33kvforcircuit751and116kvforcircuit767).ThisissueiscurrentlybeingaddressedbymodifyingtheRCPnormalstartprocedures.TheoperatorshavebeeninstructedtoverifythatadequateprestartvoltagesexistpriortoattemptinganRCPstart.Wehavecalculatedcircuit767mayalsohaveasimilarproblemwhenattemptingaSteamGeneratorFeedwaterPump(SGFWP)Start.Thiscomputeranalysisiscurrentlybeingreevaluatedtodetermineifanyexcessiveconservatismispresentintheanalysisandifrequired,theSGFWPstartprocedurewillalsobemodified.ItshouldbenotedthatCircuit767hasnothadanydifficultytodateinstartingeithertheRCPortheSGFWP.2.TheworstcaseLossofCoolantAccident(LOCA)simulationassumestwodegradedoperatingconditions:operatingsolelyonline767,(100/0mode),andamin'imumgridvoltage(116kv).Theresultsshowallbusvoltagesabove414volts,indicatingthatallofthe1Epumpmotorswilloperateandthattheundervoltagerelayingonthesebusseswillnotdisconnectthemfromoffsitepower.However,thelowest480voltMCCvoltagewas405volts,whichislowerthanRG&E'sacceptancecriteria.TheonlyloadsontheMCCsrequiredtomitigatethisaccidentwouldbeMOVs.WebelievethattheMOVswilloperateproperlyatthisvoltage,however,toprovidegreaterassurancewehaverevisedouroperatinglimitstowhichtheoffsitegrid,voltageswillbecontrolledwhensafeguardsequipmentisrequired.Whentheoffsitesupplyisprovidedinthe100/0mode(767isthelonesource)thegridvoltagewillbemaintainednolowerthan118kv.Asimulationhasbeenrunatthisvoltagewhichprovidedresultswithinallacceptancecriteria.Historicaldatademonstratesthatthegridvoltageisatleast118kvover95%ofthetime.Forthenormaloperatingmode,inthe50/50configuration,thesimulationresultsshowthatallofthevoltagesarewithintheestablishedcriteria,evenattheminimumgridvoltageof116kv.Itshouldbenotedthatthispotentiallowvoltageconditionwasnotcreatedbythereconfigurationoftheoffsitepowersystemandinfact,thelikelihoodoftheconditionoccurringwassignifi-cantlyreduced.Theabilitytoruntheoffsitepowersysteminthe50/50modewasamajorobjectiveofthepowersystemreconfigura-tionproject(EWR4525).ItshouldalsobenotedthatthemostsevereLOCAsimulationforcircuit751(0/100modeandminimumsourcevoltage33kv)resultedinacceptablevoltages.

TheprimaryobjectiveofDesignAnalysis4525-1wastoverifythatthereconfigurationoftheoffsitepowersystemdidnotresultinexcessiveshortcircuitdutiesforeithertheneworexistingequipment.Theresultsindicated.thatthereconfigurationhadanegligibleimpactontheshortcircuitdutiesfortheexisting'quipmentandthatallofthenewequipmentwasspecifiedwithshortcircuitratingswellinexcessofthecalculatedduties.Theexistingequipmentwasfoundtohaveadequateshortcircuitcapacityforallcasesexceptforonecaseofdieselgeneratortesting,discussedbelow:Aspecialcaseinvolvingthedieselgeneratorwhenitisinitsmonthlytestconfigurationwascomputersimulatedanditwasdetermined.thatpotentialshortcircuitdutiescouldexceedacceptablelimits.Thisisalowprobabilityeventrequiringaphase-to-phasefaultoccurrenceduringatwohourtestperiod.Theconsequenceofsuchaneventisaneconomicconcernonly,notasafetyissue.Theeventcouldresultinashutdownoftheplantforrepairs.Safeguardsystemredundancycouldbereduced,however,theeventwouldnotrequiretheuseofthesafeguardssystemforplantshutdown.Thisconditionwasnotcreated.bythereconfigurationoftheoffsitepowersystemandvariousalternativestoresolvethisissuearecurrentlybeingevaluated.WeexpecttobeabletoinformyouofourintendedcorrectiveactionbyOctober30,1990.Verytrulyyours,RobertC.MecreTHM/122Att'achmentsxc:Mr.AllenR.Johnson(MailStop14D1)ProjectDirectorateI-3Washington,D.C.20555U.S.NuclearRegulatoryCommissionRegionI475AllendaleRoadKingofPrussia,PA19406GinnaSeniorResidentInspector

~~~OI=I=SITEDISTRIBUTIONSYSTEMEV/R4525SIAIjASIA.204TOCSUTRAIISfOIIIIfft52I2II~I12IIXtie12BYNO12AEY12AX52NO12AYNC5252ftEMOVAQLELltIKTOVIGEtIERA)ORDUMMYBREAKERDUMMYBREAKER52525252525)52IOSIA.TOSTA.SIRV.SLRV.1ftAtIS.IRArIS.lII7pl6'..AlIIYfRAltl-Il-TOSTA.SERV.TRAtIS.g15TOSTA.SERV.TRAtlS.(ISTOSTA.TOSIA.SERV.SERV.TRAtlS.TRAtIS.pl4glSSAFCiYTRAltl"A"