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| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| document type = CORRESPONDENCE-LETTERS, INCOMING CORRESPONDENCE, UTILITY TO NRC
| page count = 5
| page count = 5
}}
=Text=
{{#Wiki_filter:ACCELERATEDD1SIBUTJONDEMONSTRATIONSYSTEM'REGULATORYINFORMATIONDISTRIBUTIONSYSTEM(RIDS)ACCESSIONNBR:8807250040DOC.DATE:88/07/18NOTARIZED:NODOCKETFACIL:50-336MillstoneNuclearPowerStation,Unit2,NortheastNu05000336I,50-423MillstoneNuclearPowerStation,Unit3,NortheastNu05000423'UTH.NAMEAUTHORAFFILIATIONMROCZKA,E.J.NortheastUtilitiesRECIP.NAMERECIPIENTAFFILIATIONDocumentControlBranch(DocumentControlDesk)
==SUBJECT:==
ForwardsinforeECCSsingle-failureanalysis.DISTRIBUTIONCODE:A001D,COPIESRECEIVED:LTR(ENCLISIZE:TITLE:ORSubmittal:GeneralDistributionNOTES:IDRECIPIENTIDCODE/NAMEPD1-4LAJAFFE,DINTERNAL:ACRSNRR/DEST/ADS7ENRR/DEST/ESB8DNRR/DEST/RSB8ENRR/PMAS/ILRB12OGC15-B-18RES/DSIR/EIBEXTERNAL:LPDRNSICCOPIESLTTRENCL1011661111111110111111RECIPIENTIDCODE/NAMEPD1-4PDFERGUSON,RARM/DAF/LFMBNRR/DEST/CEB8HNRR/DEST/MTB9HNRR/DOEA/TSBllNUDOCS-ABSTRACTI01NRCPDRCOPIESLTTRENCL551110111111111111jDDS'hTOTALNUMBEROFCOPIESREQUIRED:LTTR29ENCL26 mammalunLmamTHECCNNECTaoVTllOHTANOPOWEIICOMPANYWESTERNA$5AQtuKTTSELECTRCCOMPANYHOLYOKEWATERPOWERCOMPANYNORTHEASTVTIITEMSSERWCECOMPANYNORTHEASTNVCLEARENEROYCOMPANYGeneralOfficesmSeIdenStreet,Berlin,ConnecticutP.O.BOX270HARTFORD,CONNECTICUT06141-0270(203)665-5000July18,1988DocketNos.50-33650-423B12969U.S.NuclearRegulatoryCommissionAttn:DocumentControlDeskWashington,DC20555
==Reference:==
Gentlemen:(1)E.J.HroczkalettertoU.S.NuclearRegulatoryCommis-sion,InformationRegardingECCSSingleFailureAnalysis,datedHay12,1988.HillstoneNuclearPowerStationUnitNos.2and3InformationReardinECCSSinle-FailureAnalsisAsaresultofvalvefailure(CH-HOV-257,locatedbetweenthevolumecontroltank[VCT]andthechargingpumpsuctionheader)identifiedduringin-servicetestingonHay2,1988,ConnecticutYankeeAtomicPowerCompany(CYAPCO)evaluatedthecauseandpotentialimplicationofsuchafailureandnotedapotentialsingle-failurevulnerabilityinoneportionoftheHaddamNeckPlantemergencycorecoolingsystem(ECCS),specificallythechargingsystem.InReference(1),CYAPCOprovidedtheNRCwithinformationonthesingle-failureanalysisoftheHaddamNeckPlantECCS.Asaprudentmeasure,NortheastNuclearEnergyCompany(NNECO)conductedareviewoftheaboveinformationforapplicabilitytoNortheastUtilities'thernuclearplants(PWRsonly),namely,HillstoneUnitNos.2and3.ThepurposeofthisletteristoforwardtotheStafftheresultsofourreview.HillstoneUnitNo.2EmergencycorecoolingatHillstoneUnitNo.2isaccomplishedusinghigh-pressuresafetyinjection(HPSI),low-pressuresafetyinjection(LPSI),containmentspray(CS),shutdowncoolingheatexchangers,SIaccumulators,chargingpumps,andassoc'iatedpipinginstrumentationandvalves.HillstoneUnitNo.2hasthreepositivedisplacementchargingpumpsratedat44gpmperpump.The"A"andvC"pumpsareconnectedtoemergencyelectricalbus222andPDP0<0SS071SSSoy2~ADOCK0500033PDC
~.r~epf1hI1 U.S.NuclearRegulatoryCommissionB12969/Page2July18,198822F,respectively.The"B"pumpisaninstalledsparewhichcanbealignedtoeitheremergencybus.ThechargingpumpsarenormallyalignedtotakesuctionfromtheVCT.Uponreceiptofasafetyinjectionactuationsignal(SIAS),suctionistransferredfromtheVCTtotheboricacidstoragetanks(BASTs).TheVCTisisolatedbyagatevalve(2-CH-501)andacheckvalve(2-CH-118).FluidfromtheBASTsisdeliveredtothechargingpumpsuctionbyeitheroftwoboricacidtransferpumpsoragravityfeed(valve2-CH-508or2-CH-509)fromeachofthetwotanks.Bothboricacidtransferpumpsareonemergencyelectricalbus22F(MCCB61)andvalves2-CH-501,2-CH-508,and2-CH-509areonemergencybus22E(MCCB51).Therefore,ifbus22E(MCCB31)weretofailorvalve2-CH-501weretofailtoclose,thedischargepressureoftheboricacidtransferpumpswouldholdcheckvalve2-CH-118intheclosedpositionandeffectivelyisolatetheVCT.Conversely,ifbus22F(MCCB61)weretofail,bothboricacidtransferpumpswillfailtostart.However,valve2-CH-501willcloseonSIASandvalves2-CH-508and2-CH-509willopentoprovidethepathfromBASTstothechargingpumpsuction.ThechargingpumpsarenotrequiredduringsumprecirculationnoraretheyrequiredoncethewatersupplyintheBASTsisexhausted.IthasthereforebeenconcludedthattheMillstoneUnitNo.2chargingsystemisnotsubjecttoalimitingsinglefailuresimilartotherecentlyidentifiedproblemattheHaddamNeckPlant.MillstoneUnitNo.3EmergencycorecoolingforMillstoneUnitNo.3isaccomplishedbythecentrifugalcharging(CHS),safetyinjection(SI),andresidualheatremoval(RHS)pumps,accumulators,containmentrecirculation(CR)pumps,CRcoolers,RHSheatexchangers,andtherefuelingwaterstoragetank(RWST),alongwiththeassociatedpiping,valves,instrumentation,andotherrelatedequipmentasapplicable.AmongtheECCSfunctionsistheautomaticdeliveryofboratedwatertothereactorvesselforcoolingthecorefollowingaloss-of-coolantaccident(LOCA).Inthecaseofthechargingsystem,deliveryofwatertothecoreoccursbytransferringchargingpumpsuctionfromtheVCTtotheRWST.Specifically,onasafetyinjectionsignal(SIS),thenormalchargingsupplyfromtheVCTisisolatedbytwoseriesisolationvalves(3CHS*LCV112BandC)andtwonormallyclosed(3CHS*LCV112DandE),parallel,motor-operatedgatevalvesopentoaligntheRWSTtothechargingpumpsuction.Thesevalves(3CHS*LCV112DandE)stayopenuntiltheoperatorrealignsthesystemfortherecirculationphaseofECCSoperation.AfailuremodeandeffectsanalysisispresentedintheMillstoneUnitNo.3FSARTable6.3-10.ThisanalysisdemonstratesthatnotonlythisportionofECCScansustainthefailureofanysingleactivecomponent,butoverallECCScansustainthefailureofanysingleactivecomponentineithertheshortorlongtermandstillmeetthelevelofperformanceforcorecooling.
,~QW~U.S.NuclearRegulatoryCommissionB12969/Page3July18,1988Insummary,theMillstoneUnitNos.2and3chargingsystemsarenotsubjecttoapotentialsingle-failurevulnerabilitysimilartotherecentlyidentifiedproblemattheHaddamNeckPlant.Ifthereareanyquestionsregardingthissubmittal,pleasecontactourlicensingrepresentativedirectly.Verytrulyyours,NORTHEASTNUCLEARENERGYCOMPANYE..MroczSeniorVicePresidentcc:W.T.Russell,RegionIAdministratorD.H.Jaffe,NRCProjectManager,MillstoneUnitNos.2and3W.J.Raymond,SeniorResidentInspector,MillstoneUnitNos.1,2,and3
}}
}}

Revision as of 20:49, 25 April 2018

Forwards Results of Review of ECCS Single Failure Analysis. Facilities Charging Sys Not Subj to Potential Single Failure Vulnerability Similar to Recently Identified Problem at Haddam Neck Plant
ML17222A804
Person / Time
Site: Millstone  Dominion icon.png
Issue date: 07/18/1988
From: MROCZKA E J
NORTHEAST NUCLEAR ENERGY CO., NORTHEAST UTILITIES
To:
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
B12969, NUDOCS 8807250040
Download: ML17222A804 (5)


Text

ACCELERATEDD1SIBUTJONDEMONSTRATIONSYSTEM'REGULATORYINFORMATIONDISTRIBUTIONSYSTEM(RIDS)ACCESSIONNBR:8807250040DOC.DATE:88/07/18NOTARIZED:NODOCKETFACIL:50-336MillstoneNuclearPowerStation,Unit2,NortheastNu05000336I,50-423MillstoneNuclearPowerStation,Unit3,NortheastNu05000423'UTH.NAMEAUTHORAFFILIATIONMROCZKA,E.J.NortheastUtilitiesRECIP.NAMERECIPIENTAFFILIATIONDocumentControlBranch(DocumentControlDesk)

SUBJECT:

ForwardsinforeECCSsingle-failureanalysis.DISTRIBUTIONCODE:A001D,COPIESRECEIVED:LTR(ENCLISIZE:TITLE:ORSubmittal:GeneralDistributionNOTES:IDRECIPIENTIDCODE/NAMEPD1-4LAJAFFE,DINTERNAL:ACRSNRR/DEST/ADS7ENRR/DEST/ESB8DNRR/DEST/RSB8ENRR/PMAS/ILRB12OGC15-B-18RES/DSIR/EIBEXTERNAL:LPDRNSICCOPIESLTTRENCL1011661111111110111111RECIPIENTIDCODE/NAMEPD1-4PDFERGUSON,RARM/DAF/LFMBNRR/DEST/CEB8HNRR/DEST/MTB9HNRR/DOEA/TSBllNUDOCS-ABSTRACTI01NRCPDRCOPIESLTTRENCL551110111111111111jDDS'hTOTALNUMBEROFCOPIESREQUIRED:LTTR29ENCL26 mammalunLmamTHECCNNECTaoVTllOHTANOPOWEIICOMPANYWESTERNA$5AQtuKTTSELECTRCCOMPANYHOLYOKEWATERPOWERCOMPANYNORTHEASTVTIITEMSSERWCECOMPANYNORTHEASTNVCLEARENEROYCOMPANYGeneralOfficesmSeIdenStreet,Berlin,ConnecticutP.O.BOX270HARTFORD,CONNECTICUT06141-0270(203)665-5000July18,1988DocketNos.50-33650-423B12969U.S.NuclearRegulatoryCommissionAttn:DocumentControlDeskWashington,DC20555

Reference:

Gentlemen:(1)E.J.HroczkalettertoU.S.NuclearRegulatoryCommis-sion,InformationRegardingECCSSingleFailureAnalysis,datedHay12,1988.HillstoneNuclearPowerStationUnitNos.2and3InformationReardinECCSSinle-FailureAnalsisAsaresultofvalvefailure(CH-HOV-257,locatedbetweenthevolumecontroltank[VCT]andthechargingpumpsuctionheader)identifiedduringin-servicetestingonHay2,1988,ConnecticutYankeeAtomicPowerCompany(CYAPCO)evaluatedthecauseandpotentialimplicationofsuchafailureandnotedapotentialsingle-failurevulnerabilityinoneportionoftheHaddamNeckPlantemergencycorecoolingsystem(ECCS),specificallythechargingsystem.InReference(1),CYAPCOprovidedtheNRCwithinformationonthesingle-failureanalysisoftheHaddamNeckPlantECCS.Asaprudentmeasure,NortheastNuclearEnergyCompany(NNECO)conductedareviewoftheaboveinformationforapplicabilitytoNortheastUtilities'thernuclearplants(PWRsonly),namely,HillstoneUnitNos.2and3.ThepurposeofthisletteristoforwardtotheStafftheresultsofourreview.HillstoneUnitNo.2EmergencycorecoolingatHillstoneUnitNo.2isaccomplishedusinghigh-pressuresafetyinjection(HPSI),low-pressuresafetyinjection(LPSI),containmentspray(CS),shutdowncoolingheatexchangers,SIaccumulators,chargingpumps,andassoc'iatedpipinginstrumentationandvalves.HillstoneUnitNo.2hasthreepositivedisplacementchargingpumpsratedat44gpmperpump.The"A"andvC"pumpsareconnectedtoemergencyelectricalbus222andPDP0<0SS071SSSoy2~ADOCK0500033PDC

~.r~epf1hI1 U.S.NuclearRegulatoryCommissionB12969/Page2July18,198822F,respectively.The"B"pumpisaninstalledsparewhichcanbealignedtoeitheremergencybus.ThechargingpumpsarenormallyalignedtotakesuctionfromtheVCT.Uponreceiptofasafetyinjectionactuationsignal(SIAS),suctionistransferredfromtheVCTtotheboricacidstoragetanks(BASTs).TheVCTisisolatedbyagatevalve(2-CH-501)andacheckvalve(2-CH-118).FluidfromtheBASTsisdeliveredtothechargingpumpsuctionbyeitheroftwoboricacidtransferpumpsoragravityfeed(valve2-CH-508or2-CH-509)fromeachofthetwotanks.Bothboricacidtransferpumpsareonemergencyelectricalbus22F(MCCB61)andvalves2-CH-501,2-CH-508,and2-CH-509areonemergencybus22E(MCCB51).Therefore,ifbus22E(MCCB31)weretofailorvalve2-CH-501weretofailtoclose,thedischargepressureoftheboricacidtransferpumpswouldholdcheckvalve2-CH-118intheclosedpositionandeffectivelyisolatetheVCT.Conversely,ifbus22F(MCCB61)weretofail,bothboricacidtransferpumpswillfailtostart.However,valve2-CH-501willcloseonSIASandvalves2-CH-508and2-CH-509willopentoprovidethepathfromBASTstothechargingpumpsuction.ThechargingpumpsarenotrequiredduringsumprecirculationnoraretheyrequiredoncethewatersupplyintheBASTsisexhausted.IthasthereforebeenconcludedthattheMillstoneUnitNo.2chargingsystemisnotsubjecttoalimitingsinglefailuresimilartotherecentlyidentifiedproblemattheHaddamNeckPlant.MillstoneUnitNo.3EmergencycorecoolingforMillstoneUnitNo.3isaccomplishedbythecentrifugalcharging(CHS),safetyinjection(SI),andresidualheatremoval(RHS)pumps,accumulators,containmentrecirculation(CR)pumps,CRcoolers,RHSheatexchangers,andtherefuelingwaterstoragetank(RWST),alongwiththeassociatedpiping,valves,instrumentation,andotherrelatedequipmentasapplicable.AmongtheECCSfunctionsistheautomaticdeliveryofboratedwatertothereactorvesselforcoolingthecorefollowingaloss-of-coolantaccident(LOCA).Inthecaseofthechargingsystem,deliveryofwatertothecoreoccursbytransferringchargingpumpsuctionfromtheVCTtotheRWST.Specifically,onasafetyinjectionsignal(SIS),thenormalchargingsupplyfromtheVCTisisolatedbytwoseriesisolationvalves(3CHS*LCV112BandC)andtwonormallyclosed(3CHS*LCV112DandE),parallel,motor-operatedgatevalvesopentoaligntheRWSTtothechargingpumpsuction.Thesevalves(3CHS*LCV112DandE)stayopenuntiltheoperatorrealignsthesystemfortherecirculationphaseofECCSoperation.AfailuremodeandeffectsanalysisispresentedintheMillstoneUnitNo.3FSARTable6.3-10.ThisanalysisdemonstratesthatnotonlythisportionofECCScansustainthefailureofanysingleactivecomponent,butoverallECCScansustainthefailureofanysingleactivecomponentineithertheshortorlongtermandstillmeetthelevelofperformanceforcorecooling.

,~QW~U.S.NuclearRegulatoryCommissionB12969/Page3July18,1988Insummary,theMillstoneUnitNos.2and3chargingsystemsarenotsubjecttoapotentialsingle-failurevulnerabilitysimilartotherecentlyidentifiedproblemattheHaddamNeckPlant.Ifthereareanyquestionsregardingthissubmittal,pleasecontactourlicensingrepresentativedirectly.Verytrulyyours,NORTHEASTNUCLEARENERGYCOMPANYE..MroczSeniorVicePresidentcc:W.T.Russell,RegionIAdministratorD.H.Jaffe,NRCProjectManager,MillstoneUnitNos.2and3W.J.Raymond,SeniorResidentInspector,MillstoneUnitNos.1,2,and3