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kl Thepotentialforwaterhammerislowafterasteamlinebreaksincepromptdeliveryofauxiliaryfeedwaterinconjunctionwiththe"J"shapeddischargetubesmaintainfullfeedringsandfeedwaterpipingintheunaffectedsearngenerator,.2.6Loss-of-CoolantAccidentThepotentialfor,feedwaterwaterharmerduringapostulatedloss-of-coolantaccident(LOCA)ineitherunitwasexaminedbecauseI)awaterhammercouldincreasetheconsequencesofaLOCAand2)theplantprotectiveactionsduringaLOCAcouldresultinconditionswhichareconducivetowaterhammerifthefeedwatersystemisnotkeptfullofwater.ALOCAwouldresultinanSIS,areactortrip,aturbinetrip,andsub-sequentisolationofthefeedwatersystem.Thestartupofthemotordrivenandturbinedrivenmainauxiliaryfeedwaterpumpswouldresultandfeedwaterwouldbesuppliedtothesteamgeneratorswithin60secondsofthereactortrip.Refillofthesteamgeneratorsandrecoveryofthefeedringswouldoccurinamannertypicalofareactortriporthelossofoffsitepower.TheconditionsconducivetowaterhanmerinthefeedringsandfeedwaterpipingresultingfromaLOCAwouldbeverysimilartothoseresultingfromareactortrip.Therefore,themeanstoreducethepotentialforwaterhammerwouldbefullyeffectiveduringaLOCA.
kl Thepotentialforwaterhammerislowafterasteamlinebreaksincepromptdeliveryofauxiliaryfeedwaterinconjunctionwiththe"J"shapeddischargetubesmaintainfullfeedringsandfeedwaterpipingintheunaffectedsearngenerator,.2.6Loss-of-CoolantAccidentThepotentialfor,feedwaterwaterharmerduringapostulatedloss-of-coolantaccident(LOCA)ineitherunitwasexaminedbecauseI)awaterhammercouldincreasetheconsequencesofaLOCAand2)theplantprotectiveactionsduringaLOCAcouldresultinconditionswhichareconducivetowaterhammerifthefeedwatersystemisnotkeptfullofwater.ALOCAwouldresultinanSIS,areactortrip,aturbinetrip,andsub-sequentisolationofthefeedwatersystem.Thestartupofthemotordrivenandturbinedrivenmainauxiliaryfeedwaterpumpswouldresultandfeedwaterwouldbesuppliedtothesteamgeneratorswithin60secondsofthereactortrip.Refillofthesteamgeneratorsandrecoveryofthefeedringswouldoccurinamannertypicalofareactortriporthelossofoffsitepower.TheconditionsconducivetowaterhanmerinthefeedringsandfeedwaterpipingresultingfromaLOCAwouldbeverysimilartothoseresultingfromareactortrip.Therefore,themeanstoreducethepotentialforwaterhammerwouldbefullyeffectiveduringaLOCA.
IV.CONCLUSIONSAiVORECOMMENOATIONSTheassessment.ofthecapabilityofexistingmeanstoreducethepotentialforsteamgeneratorwaterhammerduringnormalandhypotheticaloperatingconditionswasdiscussedinSectionIII.Thisassessmenthasshownthatunderconditionswhicharemostconducivetowaterhammerinthefeedwatersystems(specifically,uncoveredanddrainingfeedringsandfeedwaterpipingsubjectedtoadmissionofcoldauxiliaryfeedwater),themeansavailabletoreducethepotentialforwaterhammeratGinnaareade-quatetomaintainsufficientlyfullfeedringsandfeedwaterpiping.Keepingthefeedringsandfeedwaterpipingfullofwateravoidsthepotentialforwaterhammer.Therefore,weconcludethatthemeanstoreducethepotentialforsteamgeneratorwaterhammeratthisfacilityareadequateandwerecommendacceptancebytheNRCstaff.
IV.CONCLUSIONSAiVORECOMMENOATIONSTheassessment.ofthecapabilityofexistingmeanstoreducethepotentialforsteamgeneratorwaterhammerduringnormalandhypotheticaloperatingconditionswasdiscussedinSectionIII.Thisassessmenthasshownthatunderconditionswhicharemostconducivetowaterhammerinthefeedwatersystems(specifically,uncoveredanddrainingfeedringsandfeedwaterpipingsubjectedtoadmissionofcoldauxiliaryfeedwater),themeansavailabletoreducethepotentialforwaterhammeratGinnaareade-quatetomaintainsufficientlyfullfeedringsandfeedwaterpiping.Keepingthefeedringsandfeedwaterpipingfullofwateravoidsthepotentialforwaterhammer.Therefore,weconcludethatthemeanstoreducethepotentialforsteamgeneratorwaterhammeratthisfacilityareadequateandwerecommendacceptancebytheNRCstaff.
REFERENCES1.G.E.Green,Roches.erGasandElectricCorp.(RGE),ltrtoJ.P.O'Reilly,NRC,"R.E.GinnaNuclearPowerPlant,UnitNo.I,FailureofSensingLineon'B'uxiliaryFeedwaterPump,AbnormalOccurrence73-6and73-7,"AugustI,1973.2.K.M.Amish,RGE,ltrtoR.T.Colson,NRC,"FeedwaterPipingTransientEvaluation,"July17,1975.:3.L.0.White,Jr.,RGE,ltrtoR.A.Purple,NRC,"SecondarySystemFluidFlowEnstability,R.E.GinnaNuclearPowerPlantUnitNo.I,"October31,1975.4.K.W.Amish,RGE,ltrtoR.A.Purole,NRC,"SpecificChangestradeatGinnaRelativetoMaterHammer,"January30,1976.5.L.D.White,Jr.,RGE,ItrtoD.Ziemann,NRC,"SteamGeneratorMaterHammerPrevention,"June15,1978.6.GinnaNuclearPowerPlantUnitNo.IUpdatedFinalFacilitDescritionandSaetAnalsisReort,RE,NRDocketNo.0-244.7.J.B.Block,etal,AnEvaluationofPMRSteamGeneratorMaterHammer,Creare,Inc.NUREG-029December98.M.E.Bennett,MaterhamnerinSteamGeneratorFeedwaterLines,WestinghouseTechnicaBueton,NSD-TB--June0,9712 f~itj vvvv~g1'v.I'lc~C~.~.si~~4Stondors(lorm1041September19)S4TreasuryFRM2000l0(2-l06PUBLICVOUCHER<FORRES'UNDSVoucherNo................C04L2-05SchcdutcNo..---------------,-,p'4.~'j~er'vv~vrv~.33X4675AppropriationorFund:ROCHESTERGASRELECCORP89EAVEROCHESTERNY14449~ATTNLDblHITEJRToAddressNUCLEARREGULATORYCOf1MISSIONU.S.(DepsrementorEstabllsbmenl,BureauorOmce)~.blASHINGTONDC20555Location:PAIDOY/2.R(-7fuv,A.vvsvs'I~-forDepositreceivedfromtheabove-nameddepositoron......................,19....hasbeenappliedasheresnstatedandthebalanceindicatedisreturnedIserelvithrv-AmountofdepositAppliedasexpIainedin"Remarks"below'.......'~v1v~~Balanceauthorizedtoberefunded4i000-00eRemarks:THENOV143979APPLICATIONblASREVIEblEDANDFOUNDNOTTOBESUBJECTTOFEEZBECAUSETHENRCISblAIVINGFEESFORCERTAINTYPESOFFIREPROTECTION,Al1ENDf1ENTS~12/31/79cc:DocketFileRefundFi1eReactorFileActivityFi1e(Signoriginalonly)Title.~vvvRefundbyheckNo..C(SignatureCash,g....-.-...-...--...on........ofpayee)Othermethod;g..........-----0v(Signorlglnalonly)(Describe)0u.s,corssIINCIIrrslaslacottlceIIsrs0sss$00tt~vv,vvI"~~~'  
REFERENCES1.G.E.Green,Roches.erGasandElectricCorp.(RGE),ltrtoJ.P.O'Reilly,NRC,"R.E.GinnaNuclearPowerPlant,UnitNo.I,FailureofSensingLineon'B'uxiliaryFeedwaterPump,AbnormalOccurrence73-6and73-7,"AugustI,1973.2.K.M.Amish,RGE,ltrtoR.T.Colson,NRC,"FeedwaterPipingTransientEvaluation,"July17,1975.:3.L.0.White,Jr.,RGE,ltrtoR.A.Purple,NRC,"SecondarySystemFluidFlowEnstability,R.E.GinnaNuclearPowerPlantUnitNo.I,"October31,1975.4.K.W.Amish,RGE,ltrtoR.A.Purole,NRC,"SpecificChangestradeatGinnaRelativetoMaterHammer,"January30,1976.5.L.D.White,Jr.,RGE,ItrtoD.Ziemann,NRC,"SteamGeneratorMaterHammerPrevention,"June15,1978.6.GinnaNuclearPowerPlantUnitNo.IUpdatedFinalFacilitDescritionandSaetAnalsisReort,RE,NRDocketNo.0-244.7.J.B.Block,etal,AnEvaluationofPMRSteamGeneratorMaterHammer,Creare,Inc.NUREG-029December98.M.E.Bennett,MaterhamnerinSteamGeneratorFeedwaterLines,WestinghouseTechnicaBueton,NSD-TB--June0,9712 f~itj vvvv~g1'v.I'lc~C~.~.si~~4Stondors(lorm1041September19)S4TreasuryFRM2000l0(2-l06PUBLICVOUCHER<FORRES'UNDSVoucherNo................C04L2-05SchcdutcNo..---------------,-,p'4.~'j~er'vv~vrv~.33X4675AppropriationorFund:ROCHESTERGASRELECCORP89EAVEROCHESTERNY14449~ATTNLDblHITEJRToAddressNUCLEARREGULATORYCOf1MISSIONU.S.(DepsrementorEstabllsbmenl,BureauorOmce)~.blASHINGTONDC20555Location:PAIDOY/2.R(-7fuv,A.vvsvs'I~-forDepositreceivedfromtheabove-nameddepositoron......................,19....hasbeenappliedasheresnstatedandthebalanceindicatedisreturnedIserelvithrv-AmountofdepositAppliedasexpIainedin"Remarks"below'.......'~v1v~~Balanceauthorizedtoberefunded4i000-00eRemarks:THENOV143979APPLICATIONblASREVIEblEDANDFOUNDNOTTOBESUBJECTTOFEEZBECAUSETHENRCISblAIVINGFEESFORCERTAINTYPESOFFIREPROTECTION,Al1ENDf1ENTS~12/31/79cc:DocketFileRefundFi1eReactorFileActivityFi1e(Signoriginalonly)Title.~vvvRefundbyheckNo..C(SignatureCash,g....-.-...-...--...on........ofpayee)Othermethod;g..........-----0v(Signorlglnalonly)(Describe)0u.s,corssIINCIIrrslaslacottlceIIsrs0sss$00tt~vv,vvI"~~~'}}
}}

Revision as of 15:29, 18 May 2018

Steam Generator Water Hammer Technical Evaluation.
ML17249A345
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Issue date: 10/31/1979
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TASK-05-13, TASK-5-13, TASK-RR NUDOCS 7912190066
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STEAMGENERATORWATERHAMMERTECHNICALEVALUATIONGINNAPOWERSTATIONOCTOBER1979EG5GIDAHO,INC.7918190 CONTENTSIVV,2.4OperatorError2.5SteamLineBreak.2.6Loss-of-CoolantAccident.CONCLUSIONSANDRECOMMENDATIONSREFERENCES.I.INTRODUCTION.II.FEEDMATERSYSTEM.1.DESCRIPTION.2.GENERALOPERATION.III.MEANSTOREDUCETHEPOTENTIALFORMATER1.DESCRIPTION.2.EFFECTIVENESSDURINGTRANSIENTSANDCONDUCIVETOMATERHAMMER.2.1ReactorTrip.2.2LossofMainFeedwaterFlow.2.3LossofOffsitePower.HAMMER.CONDITIONS~~I22~~35577788910~1112 t

I.'NTRODUCTIONAnevaluationwasperformedfortheGinnafeedwatersystem.Thepurposeofthisevaluationwastoassesstheeffectivenessoftheexistingmeanstoreducethepotentialforsteamgeneratorwaterhammerinthefeedwatersystemduringnormalandhypotheticaloperatingconditions.Thesteam-waterslugginginthefeedwatersystems(specifically,thesteamgeneratorfeedwaterspargerringsandadjacentfeedwaterpiping)wasconsideredinthisreview.NoknownwaterhammereventdirectlyattributabletofeedwaterringdraininghasoccurredatGinna.Twowaterhammertransientscausedbyfeedwatercontrolvalvemalfunctiondidhappen,however.Thepotentialforsteamgeneratorwaterhammerisavoidedifthefeed-watersystemismaintainedfullofwater.Hence,thisevaluationwasbasedontheeffectivenessofthemeansutilizedatGinnatomaintainthefeedwatersystemfullofwaterduringnormalandhypotheticaloperatingconditions.Theinformationforthisevaluationwasobtainedfrom:1)discussionswiththelicensee,2)licenseesubmittalsofAugust1,1973,July17,Lll1975~,October31,1975~,January30,1976E,andJune15,1978"",r5~3)the"GinnaNuclearPlantFinalSafetyAnalysisReport"~j,4)"AnEvalu-ationofPMRSteamGeneratorMaterHamner,"NUREG-0291,and5)Mesting-[71houseTechnicalBulletin,NSD-TB-75-7"rBjAdescriptionofthefeedwatersystematGinnaanditsgeneraloperationispresentedinSectionII.Themeanstoreducethepotentialforsteamgen-eratorwaterhammerarepresentedinSectionIII,includingadiscussionoftheireffectivenessduringoperatingconditionsconducivetowaterhammer.Finally,conclusionsandrecommendationsarepresentedinSectionIVconcern-ingtheadequacyoftheexistingmeanstoreducethepotentialforsteamgeneratorwaterhammeratthisfacility.

IV II.FEEDWATERSYSTEM1.DESCRIPTIONThefeedwatersystemforGinnawasdesignedtoprovideanadequatesupplyoffeedwatertothesecondarysideofthetwosteamgeneratorsduringalloperationalconditions.Feedwaierissuppliedtothemainfeedwaterpumpsbytheheaterdrainpumpsandbythecondensatepumpsviathelowpressureheaters.Feedwaterfromthemainfeedwaterpumpsissuppliedtoamainheaderviathehighpressureheaters.Themainheadersplitsintotwo14-inchfeedwaterlinestosupplya10.75-inchdiameter,half-inchwallthicknessfeedringinsideeachsteamgenerator.Feedwaterisdischargeddownwardthroughinverted"J"shapedtubesuniformlydistributedontopofeachfedring.Thetwomainfeedwaterpumpsaresinglestage,doubleflow,centrifugaltype,eachratedforaflowrateof14,000gpmat853psig.Thetwopumps,eachdrivenbya5000hpelectricmotor,sharecommonsuctionanddischargeheaders.Thepumpmotorsarenormallysuppliedwithpowerviathemainauxiliarytransformer.Intheeventofaturbinetrip,offsitepowersuppliesthepumpmotorsviathereserveauxiliarytransformer.Theauxiliaryfeedwatersystem(APrlS)providesfeedwatertothesteamgeneratorsforresidualheatremovalduringreactorstartupandshutdown,lowpoweroperation,andintheeventoflossofmainfeedwaterflow.TheASSconsistsofamain(M)AFWSandastandby(SB)AFWS.The(M)ASSconsistsof2motor-drivenpumps,each200gpmcapacityand1turbine-driven,400gpmcapacity.Eachmotor-drivenpumpcansupplyeitheroneorbothsteamgenerators.Theturbine.-drivenpumpnormallysuppliesboihsteamgenerators.Theprimarysourceofwateristwo30,000galloncondensatestoragetankswhicharecross-connectedthroughlocked-openmanuallyoperatedvalves,whilethebackupsupplyisavailablefromtheservicewatersystem.Theturbine-drivenpumpissuppliedwithsteamfromthemainheaders.Tne(SB)AFWSconsistsof2motor-drivenpumps,each200gpmcapac.'ty.Thissystemwas-installedinaseparateplantareafromthe(M)APASduringAugust1979,toprovideindependentASScapabilityfollowingasteamorfed-waterlinebreakintheimmediatevicinityofthe(M)AFWSpumps.Theprimarywatersourceistheservicewatersystem.

1t ThetwoAFASareeachpoweredfrom2redundantandindependentACemer-gencybusesfromplantemergencydieselgenerators.TheyareinterlockedsothatbotharenotsimultaneouslyloadedontothevitalACbuses.The(M)AFWSsuppliesfeedwatertoeachsteamgeneratorvia2three-inchlinesconnectedtoeachmainfeedwaterlinejustoutsidethecontainmentbuilding.The(SB)AFMSconnectionstoeachmainfeedwaterlineareplacedwithinthecontainmentbuildingviaonelinepersteamgenerator.Theyarecapableofbeingcross-connected.bytheoperationofmanualvalves.Allvalvesbetweenthepumpsandthesteamgeneratorsarelockedopen.2.GBIERALOPERATIONOuringnormalpoweroperationofthereactor,themainfeedwatersystemsuppliesfeedwatertothesecondarysideofthesteamgeneratorsforheatremovalfromthereactorcoolantsystem.Thefeedwaterflowisregulatedbyindividualregulatingvalvesinthemainfeedwaterlinestoeachsteamgenerator.Thepositionsofthevalvesareautomaticallycontrolledbaseduponsteamgeneratorlevel,steamflow,andfeedwaterflow.Ouringplantshutdown,startup,andforfeedwaterrequirementsuptoabout3Xoffullreactorpower,feedwaterisnormallysuppliedbythemainauxiliaryfeedwatersystem.Feedwaterflowismanuallyregulatedtomain-tainadequatewaterlevelsinthesteamgenerators.Aspowerisincreasedandsufficienthighpressuresteamisavailable,amainfeedwaterpumpisstartedandtheauxiliaryfeedwatersystemisshutdown.Forfeedwaterrequirementsofabout3XtoI55offullpower,>eedwaterismanuallycontrolledandsuppliedvialowflowbypasslineswhichbypassthemainfeedwaierregulatingvalveineachmainfeedwaterline.Thebypassregulatingvalveineachbypasslineallowsmoreaccurateandresponsiveeedwaterflowcontrolthanwouldbepossiblewiththelargermainregulatingvalvesduringlowpower(andlowfeedwaterflow)operation.Abovefeedwaterrequirementsofabout15"offullreactorpower,feedwatercontrolisshiftedtothemainregulatingvalves.Aspowerisincreasedto50-o0~offullpower,thesecondmainfeedwaterpumpisstartedandfeedwaterflowisplacedunderautomaticcontrol.

Afterthelossofmainfeedwaterflowtooneorbothsteamgenerators,automaticinitiationofthemainauxiliaryfeedwaterflowwillresultuponreceiptofoneormoreauxiliaryfeedwaterpumpstartupsignals.Themotordrivenauxiliaryfeedwaterpumpsstarton:I)thecoincidenceoftwooutofthreesteamgeneratorlow-Iowwaterlevel(15"ofnarrowrange,or1.3inchesabovethebottomsurfaceofthefeedring)signalsfromeithersteamgenerator,2)thetrippingofbothmainfeedwaterpumps,or3)asafetyinjectionsignal(SIS).Theturbinedrivenauxiliaryfeedwaterpumpstartson:I)thecoinci-denceoftwooutofthreesteamgeneratorlow-lowwaterlevelsignalsfrombothsteamgeneratorsor2)thecoincidenceofaturbine-generatortripandlossofoffsitepower.Theauxiliaryfeedwaterissubsequentlymanuallycontrolledtomaintainproperwaterlevelsinallsteamgenerators.Themotordrivenandturbinedrivenauxiliaryfeedwaterpumpscanalsobestartedmanually(localorremote).The(SB)ASSismanuallyinitiated.Plantdesignspecificationsallowforamaximumdelayofoneminutefromreceiptofanyauxiliaryfeedwaterpumpstartupsignalstodeliveryofmainauxiliaryfeedwatertothesteamgenerators.Alimitoftenminutesisallowedtogetthe(SB)AFMSonstream.OperatingprocedurestoadministrativelylimitauxiliaryfeedwaterIowduringrecoveryofthesteamgeneratorfeedringsfromnormalandabnormaltransientshavebeenimplementedatGinna.Inthesesituations,theauxiliaryfeedwaterflowratetoeithersteamgeneratoristobemanuallylimitedtoamaximumof150gpm.Thislimitationistoapplywheneversteamgeneratorlevelisbelowthelow-Iowlevelsetpoint,15%%dofnarrowrange,anduntilthelevelisrecoveredto255(Iinchabovethetopofthering).Thislimitationisnotapplicableintheeventofsafetyinjectioninvolvingwaterlevelsfarbelowthefeedring.Boththemainandstandbyauxiliaryfeedwatersystemsflowpathstothesteamgeneratorsarenotisolatedautomaticallyasaresultofasteamorfeedwater(mainorauxiliary)linebreak.Theisolationisaccomplishedmanually.

III.MEANSTOREDUCETHEPOTENTIALFORWATERHAMMER1.DESCRIPTIONThefollowingaremeanscurrentlyemployedatGinnatoreducethepotentialforsteamgeneratorwaterhammer:1."J"shapeddischargetubesonallsteamgeneratorfeed-ringsinconjunctionwiththepromptautomaticinitiationofauxiliaryfeedwaterflowuponlossofmainfeedwaterflowand/orsteamgeneratorfeedringuncovery.2.AdministrativecontrolstolimitauxiliaryfeedwaterflowL7]tolessthan150gpmpersteamgeneratorduringperiodsofsteamgeneratorfeedringuncovery.3.Thereductionoftheeffecitvehorizontalsectionofmainfeedwaterpipingattheentrancetoallsteamgeneratorstolessthaneightfeet~~.The"J"shapeddischargetubeswereinstalledontopofthefedringsandthebottomholeswerepluggedtoprovidefortopdischargeofwaterratherthanbottomdischarge.Duringperiodsoffeedringuncovery,thisarrangementincreasesthetimeforcompletedrainageofthefeedringsandassociatedhorizontalfeedwaterpipingfromlessthanoneminutetoabout30minutes.Also,themaximummainauxiliaryfeedwaterflow(about400gpmpersteamgenerator)wasnotsuficienttomaintainthefeedringsandfeed-waterpipingfullofwaterwhenthefeedringshadbottomdischargeholes.Thefedringsequippedwith"J"shapeddischargetubes,however,permitfeedwaterflowratesaslowasabout10gpmpersteamgeneratortokeepthefeedringsandfeedwaterpipingfullofwateruntilfeedringrecoveryoccurs.Substantialdrainageofthefeedringsandpipingviathefeedringfittingclearancedoesnotoccurforaboutfiveminuteswhichallowstimeforautomaticactuationofthemainauxiliaryfeedwatersystemafterthelossofmainfeedwaterflow.Thepotentialforwaterharrierisavoidedifthefeedringsandfeedwaterpipingarekeptfullofwater.

P

'I"Thepromptautomati'c'startupofanyone"mainauxiliaryfeedwaterpumpafterthelossofmainfeedwaterflowprovidesfeedwaterflowtokeepthefedringsandfeedwaterpipingfullofwater,Hecausethe"J"shapeddis-chargetubesreducetheleakagefromthefeedring,theauxiliaryfeedwaterflowfromeitherofthemotordrivenpumpsortheturbinedrivenpumpismorethansufficienttokeepthefeedwatersystemfullofwater.ThepresentGinnamainfeedwaterpipinggeometryadjacenttoeachsteamgeneratorconsistsofahorizontalrunfromthesteamgeneratortothefirstdownwardturningelbowineachline.Thehorizontalrunsare2feet3inchesfromthenozzletothecenterlineofthedownwardlegoftheelbow,wellwithinthevendor'srecommendationstominimizewaterhammerdamagetothefeedwaterpipingsystem.Priortothedecisiontoinstall"J"tubesananalysisoftheGinnamainfeedwaterpipingusingapreliminary,Mestinghouse-deriveddynamicforcingfunctionwasperformed.Assumptionswerethatthesteam-water~331sluginitiatedatthesteamgenerators;thatauxiliaryfeedwaterwasinuse;andthatthemainfeedwatercheckvalveswereclosed.ThetimedependentmathematicalfunctionwasmodifiedfortheGinnapipingconfiguration.Thetimehistoryoftheacousticshockwavegeneratedbythesteam-waterslugwasevaluatedwithrespecttostresscriteriabasedonallowablestressobtainedfromtheoriginalconstructioncode.Theresultsshowedthattherewereseverallocationsinbothfeedwaterpipingsystemswhichexceededthestresscriteria."J"tubessubsequentlywereinstalledtoreducethepoten-tialforwaterhammer.NotestprogramshavebeenperformedatGinnatodeterminewhetheranywaterhammertransientwouldoccurasaresultofuncoveringofthesteamgeneratorfeedrings.However,bothfeedwaterlinesinsideofcontainmentwereinstrumentedfollowingthe1975transienttoprovidethecontrolroomoperatorwithpipingvibrationinformationduringplantstartup.

If'l 2.EFFECTIVENESSOURINGTRANSIENTSANOCONOITIONSCONOUCIVETOMATERHANMERTnenormalandhypotheticaltransientsandconditionsconducivetosteamgeneratorwaterhammerarediscussedinthissection.Hiththeexcep-tionofsubsection2.4entitled"OperatorError",eachsubsectiondescribesatransientresultingfromasingleinitiatingeventorfailurewiththeunitinnormalpoweroperation.potentialcomponentorsystemfailuresasadirectresultofahypotheticalsteamgeneratorwaterhaftmerareaccountedforintheanalysis.Asinglecriterionwasthebasisforevaluatingtheeffectivenessofthemeanstoadequatelyreducethepotentialforsteamgeneratorwaterhammer.Thecriterionistomaintainthefeedwatersystemfullofwaterduringthetimefromtheinitiatingeventresultinginfeedringuncoverytosubsequentfeedringrecoveryandstabilizedsteamgeneratorwaterinventory.2.1Areactortripwiththeplantinnormalpoweroperationwouldresultinaturbinetripandcausethewaterlevelinallsteamgeneratorstocollapsetoalevelbelowthefeedrings.Mithin60secondsoftheresultingsteamgeneratorlow-Iowwaterlevelsignals,themotordrivenandturbinedrivenmainauxiliaryfeedwaterpumpswouldautomaticallystartandsupplyauxiliaryfeedwatertothesteamgenerators.Iftheinitiatingeventforthereactortripdidnotclosethemainfeedwaterregulatingvalves,thevalveswouldcloseuponreceiptof:I)lowprimarycoolantaveragetemperaturesignals,2)steamgeneratorhigh-highwaterlevelsignals,or3)anS/S.Auxiliaryfeedwaterwouldthenbemanuallycontrolledtorestorethewaterlevelsinthesteamgeneratorsandmaintainthelevelsabovethefeedrings.Thepotentialforwaterhammeroccurringinthefeedringorfeedwaterpipingafterareactortripisverylowbecausethemainandauxiliaryfeed-waterkeepstheeedringsandfeedwaierpipingfullofwater.r2.2LossofMainFedwaterFlowThemainfeedwatersupplycouldbeinterruptedduetotheI)lossofoffsitepower,2)malfunctionortrippingofthemainfedwaterpumps,7

'I 3)lossofsuctiontothemainfeedwaterpumps,or4)closureofthemainfeed-waterregulatingand/orisolationvalves.Areactortripwouldoccuruponreceiptoftheresultingsteam/feedwaterflowmismatchsignalsandlowsteamgeneratorwaterlevelsignals.Thereactortripwouldcuasethewaterlevelsinallsteamgeneratorstocollapsetoalevelbelowthefeedrings.Themotordrivenandturbinedrivenmainauxiliaryfeedwaterpumpswould'startuponreceiptofthesubsequentIow-lowsteamgeneratorwaterlevelsignals.Auxiliaryfeedwater'wouldthenbeusedtorefillthesteamgeneratorsandrecoverthefeedrings.ThelossofmainfeedwaterflowandtheIikeIyuncoveryofthefeedringswouldnotresultinsubstantialfeedringandfeedwaterpipingdrainagesincethemainauxiliaryfeedwaterpumpswouldstartpromptlytosupplyfeedwatertothesteamgenerators.Therefore,thepotentialforwaterhammerissignificantlyreduced.2.3LossofOffsitePowerThecompleteinterruptionofoffsitepowerwouldresultinareactortripandautomaticstartupoftheemergencydieselgenerators.Automaticinitiationofthemotordrivenandturbinedrivenmainauxiliaryfeedwatersystemswouldoccurtosupplyfeedwatertothesteamgenerators.TheredundantauxiliaryfeedwatersystemsarefullyfunctionalwithoutoffsitepowersincethedieselgeneratorsandOCbatteriescansupplyallnecessaryelectricalpowertobothsystems.Aswasthecaseforthelossofmainfeedwaterflow,auxiliaryfeedwaterflowwouldmaintainthefeedringsandfeedwaterpipingfullofwateruntilfeedringrecoveryoccursandagainthepotentialforwaterhammerwouldbeveryIow.2.4OperatorErrorThepotentialforwaterhammerinthefeedwatersystemincreasesifuncoveredfeedringsareallowedtodrainsubstantiallyafteranevent'ausesthesteamgeneratorwaterlevelstodropbelowthefeedrings.Admissionoffeedwaierintothedrainedfeedringsandhorizontalfeedwaterpipingcouldthenresultinwatersluggingandsubsequentwaterhammer.Theuncoveryofoneorbothfeedringsispossiblethroughoperatorerrorwhentheplantis I

operatingatlowpowerorduringstartuporwhileshuttingdownsincefeed-swaterisbeingregulatedmanually,ratherthanautomatically.Forthis-situ-ation,anadministrativelimitof150gpmonauxiliary,feedwaterflowhasbeenimplementedintheoperatingprocedures.ThislimitationwasrecommendedinReference7basedontestsatIndianPoint.2.5SteamLineBreakThepotentialforsteamgeneratorwaterhammereventsresultingfromorconcurrentwiththeruptureofasteamlineinsidecontainmentwasconsidered.Thesequenceofeventsfollowingsuchafailurewasevaluatedtodetermineifthebreakcouldresultinthe1)blowdownoftheremainingsteamgeneratorand/or2)inabilitytosupplyauxiliaryfeedwatertotheunaffectedsteamgenerator.TheruptureofasteamlinewouldautomaticallyresultinanSIScausingareactortrip,aturbinetrip,andisolationofallmainfeedwaterlines.Theloss.ofmainfeedwaterflowtothesteamgeneratorswouldresultintheautomaticstartupofthemotordrivenandturbinedrivenmainauxiliaryfeed-waterpumpsuponreceiptoflow-lowsteamgeneratorwaterlevelsignals.Auxiliaryfeedwaterwouldcontinuetobesuppliedforsubsequentrefilloftheunaffectedsteamgeneratorandrecoveryofthefeedring.However,iftheruptureoccursintheimmediatevicinityofthemainauxiliaryfeedwaterpumpsandrenderstheminoperable,theoperatingproceduresallowtenminutesfortheoperationofswitchesinthecontrolroomthatwillisolatethe(N)A'FMSandgetthe(SB)AFWSonstream.Althoughihefeedringmightdrainsignificantlyinthattime,theadministrativelimitof150gpmofauxiliaryfeedwaterflowwillreducethepotentialofwaterhammeroccurrence.ThislimitationisconsideredapplicableatGinnabasedonthebestavailableinformationobtainedintestsatIndianPoint.Theblowdownofasteamgeneratorwouldnotdeprivetheturbinedrivenauxiliaryfeedwaterpumpofdrivingsteam..Acheckvalveineachsteamsupplylinewouldprevent."crossover"blowdownthroughthesupplylinesfromtheunaffectedsteamgeneratortotheassociatedblowndownsteamgenerator.

kl Thepotentialforwaterhammerislowafterasteamlinebreaksincepromptdeliveryofauxiliaryfeedwaterinconjunctionwiththe"J"shapeddischargetubesmaintainfullfeedringsandfeedwaterpipingintheunaffectedsearngenerator,.2.6Loss-of-CoolantAccidentThepotentialfor,feedwaterwaterharmerduringapostulatedloss-of-coolantaccident(LOCA)ineitherunitwasexaminedbecauseI)awaterhammercouldincreasetheconsequencesofaLOCAand2)theplantprotectiveactionsduringaLOCAcouldresultinconditionswhichareconducivetowaterhammerifthefeedwatersystemisnotkeptfullofwater.ALOCAwouldresultinanSIS,areactortrip,aturbinetrip,andsub-sequentisolationofthefeedwatersystem.Thestartupofthemotordrivenandturbinedrivenmainauxiliaryfeedwaterpumpswouldresultandfeedwaterwouldbesuppliedtothesteamgeneratorswithin60secondsofthereactortrip.Refillofthesteamgeneratorsandrecoveryofthefeedringswouldoccurinamannertypicalofareactortriporthelossofoffsitepower.TheconditionsconducivetowaterhanmerinthefeedringsandfeedwaterpipingresultingfromaLOCAwouldbeverysimilartothoseresultingfromareactortrip.Therefore,themeanstoreducethepotentialforwaterhammerwouldbefullyeffectiveduringaLOCA.

IV.CONCLUSIONSAiVORECOMMENOATIONSTheassessment.ofthecapabilityofexistingmeanstoreducethepotentialforsteamgeneratorwaterhammerduringnormalandhypotheticaloperatingconditionswasdiscussedinSectionIII.Thisassessmenthasshownthatunderconditionswhicharemostconducivetowaterhammerinthefeedwatersystems(specifically,uncoveredanddrainingfeedringsandfeedwaterpipingsubjectedtoadmissionofcoldauxiliaryfeedwater),themeansavailabletoreducethepotentialforwaterhammeratGinnaareade-quatetomaintainsufficientlyfullfeedringsandfeedwaterpiping.Keepingthefeedringsandfeedwaterpipingfullofwateravoidsthepotentialforwaterhammer.Therefore,weconcludethatthemeanstoreducethepotentialforsteamgeneratorwaterhammeratthisfacilityareadequateandwerecommendacceptancebytheNRCstaff.

REFERENCES1.G.E.Green,Roches.erGasandElectricCorp.(RGE),ltrtoJ.P.O'Reilly,NRC,"R.E.GinnaNuclearPowerPlant,UnitNo.I,FailureofSensingLineon'B'uxiliaryFeedwaterPump,AbnormalOccurrence73-6and73-7,"AugustI,1973.2.K.M.Amish,RGE,ltrtoR.T.Colson,NRC,"FeedwaterPipingTransientEvaluation,"July17,1975.:3.L.0.White,Jr.,RGE,ltrtoR.A.Purple,NRC,"SecondarySystemFluidFlowEnstability,R.E.GinnaNuclearPowerPlantUnitNo.I,"October31,1975.4.K.W.Amish,RGE,ltrtoR.A.Purole,NRC,"SpecificChangestradeatGinnaRelativetoMaterHammer,"January30,1976.5.L.D.White,Jr.,RGE,ItrtoD.Ziemann,NRC,"SteamGeneratorMaterHammerPrevention,"June15,1978.6.GinnaNuclearPowerPlantUnitNo.IUpdatedFinalFacilitDescritionandSaetAnalsisReort,RE,NRDocketNo.0-244.7.J.B.Block,etal,AnEvaluationofPMRSteamGeneratorMaterHammer,Creare,Inc.NUREG-029December98.M.E.Bennett,MaterhamnerinSteamGeneratorFeedwaterLines,WestinghouseTechnicaBueton,NSD-TB--June0,9712 f~itj vvvv~g1'v.I'lc~C~.~.si~~4Stondors(lorm1041September19)S4TreasuryFRM2000l0(2-l06PUBLICVOUCHER<FORRES'UNDSVoucherNo................C04L2-05SchcdutcNo..---------------,-,p'4.~'j~er'vv~vrv~.33X4675AppropriationorFund:ROCHESTERGASRELECCORP89EAVEROCHESTERNY14449~ATTNLDblHITEJRToAddressNUCLEARREGULATORYCOf1MISSIONU.S.(DepsrementorEstabllsbmenl,BureauorOmce)~.blASHINGTONDC20555Location:PAIDOY/2.R(-7fuv,A.vvsvs'I~-forDepositreceivedfromtheabove-nameddepositoron......................,19....hasbeenappliedasheresnstatedandthebalanceindicatedisreturnedIserelvithrv-AmountofdepositAppliedasexpIainedin"Remarks"below'.......'~v1v~~Balanceauthorizedtoberefunded4i000-00eRemarks:THENOV143979APPLICATIONblASREVIEblEDANDFOUNDNOTTOBESUBJECTTOFEEZBECAUSETHENRCISblAIVINGFEESFORCERTAINTYPESOFFIREPROTECTION,Al1ENDf1ENTS~12/31/79cc:DocketFileRefundFi1eReactorFileActivityFi1e(Signoriginalonly)Title.~vvvRefundbyheckNo..C(SignatureCash,g....-.-...-...--...on........ofpayee)Othermethod;g..........-----0v(Signorlglnalonly)(Describe)0u.s,corssIINCIIrrslaslacottlceIIsrs0sss$00tt~vv,vvI"~~~'