ML18026A416

Forwards Response to NRC 910730 Request for Addl Info Re Proposed Amend 137 to License NPF-14 & Proposed Amend 91 to License NPF-22 Re Elimination of Temp Leak Detection Isolation Function in RHR Room

ML18026A416
Person / Time
Site:	Susquehanna
Issue date:	03/03/1992
From:	KEISER H W PENNSYLVANIA POWER & LIGHT CO.
To:	MILLER C L Office of Nuclear Reactor Regulation
Shared Package
ML17157B072	List: ML17157B071 ML18026A416
References
PLA-3732, NUDOCS 9203090230
Download: ML18026A416 (92)

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ACCELERATEDDISTRIBUTIONDEMONST$&TIONSYSTEMREGULAOtYINFORMATIONDZSTRIBUTZOSYSTEM(RIDE)ACCESSIONNBR:9203090230DOC.DATE:92/03/03NOTARIZED:NOFACIL:50-387SusquehannaSteamElectricStation,'Unit1,Pennsylva50-.388SusquehannaSteamElectricStation,Unit2,PennsylvaAUTH.NAMEAUTHORAFFILIATION'-'KEISER,H.W.PennsylvaniaPower6LightCo.RECIP.NAMERECIPIENTAFFILIATIONMILLERFC.L.OfficeofNuclearReactorRegulation,Director(DOCKETg0500038705000388st870411

SUBJECT:

RespondstorequestforadditionalinforelicensetoamendNPF-22.DISTRIBUTIONCODE:AOOZDCOPIESRECEIVED:LTRtENCLgSIZE'+TITLE:ORSubmittal:GeneralDistributionDNOTES:LPDR1cyTranscripts.LPDR1cyTranscripts.S0500038705000388/RECIPIENTIDCODE/NAMEPD1-2IARALEIGH,J.COPIESLTTRENCL1122RECIPIENTIDCODE/NAMEPD1-2PDCOPI'ESLTTRENCL11DDINTERNAL:ACRSNRR/DET/ESGBNRR/DST8E2NRR/DST/SICB8H7NUDOCS-ABSTRACTOGC/HDS2RES/DSIR/EIBEXTERNAL:NRCPDRNOTES:6NRR/DET/ECMB7D1NRR/DOEA/OTSB111NRR/DST/SELB7E1NRR/DST/SRXB8E1OC/WNB~0~EL~IFEN011NSIC2211111111101111RDNOTETOALL"RIDS"RECIPIENTS:ADDPLEASEHELPUSTOREDUCEWAS'ONTACTTHEDOCUMENTCONTROLDESK,ROOMP1-37(EXT.20079)TOELIMINATEYOURNAMEFROMDISTRIBUTIONLISTSFORDOCUMENTSYOUDON'TNEED!TOTALNUMBEROFCOPIESREQUIRED:LTTR26ENCL24 NARO31g92PennsylvaniaPower8LightCompanyTwoNorthNinthStreet~Allentown,PA18101-1179~215/774-5151HaroldW.KelserSeniorVicePresident-Nuclear215/774<194DirectorofNuclearReactorRegulationAttention:Mr.C.L.Miller,ProjectDirectorProjectDirectorateI-2DivisionofReactorProjectsU.S.NuclearRegulatoryCommissionWashington,D.C.20555SUSQUEHANNASTEAMELECTRICSTATIONRESPONSETOREQUESTFORADDITIONALINFORMATIONONPROPOSEDAMENDMENTNOS.137TOLICENSENO.NPF-14AND91TOLICENSENO.NPF-22:ELIMINATIONOFTEMPERATURELEAKDETECTIONISOLATIONFUNCTIONINRHRROOMPLA-372FILR41-2A17-2DocketNos.50-387and50-388

DearMr.Miller:

ThisletterisinresponsetotheNRCstaff'srequestforadditionalinformationregardingourrequestedrevisionstotheTechnicalSpecificationsforSusquehannaSESrelatedtotheeliminationofthetemperatureleakdetectionisolationfunctionsintheRHRroom.ThefollowingmaterialprovidesspecificresponsestothestaffquestionscontainedinaletterdatedJuly30,1991.REUETNIThelicenseehashadpreviousdiscussionswiththestaffregardingthismatterandforcompleteness,thesubmittalshouldmakereferencetothesediscussionsandshouldincludeasummaryofthemajorpointsofdiscussionandanyconclusionsthatwerereached.'R~esonse:IfOnFebruary5,1991,PP&LandNRCstaffheldameetingin'heNRCofficeinWhiteFlint,MarylandtodiscussissuesrelatedtoPP&Lsteamleakdetectionsystem.ThefollowingareexcerptswhichdiscusstheRHRroomissuesfromPP&L'ssummaryofthatmeeting:OOOO"'J9203070230920303PDRADOCK05000387PPDR FILESR41-2/A17-2PLA-3732Mr.C.L.MillerThepurposeofthismeetingwastodiscussPP&LactionstakentoclosethesteamleakdetectionissueandtoobtainNRC'spreliminaryconcurrenceontheactiontaken.Copiesoftheslidesusedduringthe'presentationareattachedasAttachment'A.'hedetailedtopicsdiscussedwere:I1.Thechangeinthedesignbasisleakageratefrom5gpmto25gpmintheHPCI,RCIC,andRWCUareas.(TechSpecchangesubmitted)2.Thedeletionoftheambienttemperatureisolationintheturbinebuildingmainsteamtunnel.3.ThedeletionoftheambientanddeltatemperatureisolationintheRHRrooms.(TechSpecchangesubmitted)4.NotchangingtheallowablevalueintheTechnicalSpecificationfortheReactorBuildingmainsteamtunnel.PP&LpresentedadiscussiononthedeletionofthetemperatureanddeltatemperatureisolationintheRHRroomsbasedonthefactthatthesteamcondensingmodeofRHRwasremovedfromtheplant;andtherefore,therearenohighenergylinesintheRHRroom.TheNRCstaffwasreceptivetothisdeletion.REET2Itisnotclearwhyitisnecessarytodeletetheisolationfunction.Thisshouldbeexplainedindetail.Also,areotheroptionsavailable,suchasenablingtheisolationfunctiononlyforperiodswhentheRHRsystemisnotisolatedfromthereactorcoolantsystemand/orestablishingahigherleakrateasthebasisforisolation?~Res~onThePP&LrequesttoeliminateautomaticisolationofRHRshutdowncooling,documentedinPLA-34851/14/91,wasbasedonanumberofconsiderations.ElimininfmndeninMode:OriginaltemperatureisolationsetpointsintheRHRroomareaareconsistentwithsetpointsintheHPCIandRCICareas,andarebasedupontemperatureincreasesintheseroomscausedbyleakingsteamatnormalfullpoweroperatingconditions.In1987(Unit1)and1989(Unit2)thesteamcondensingmodeofoperationoftheRHRsystemwaseliminated FILESR41-2/A17-2PLA-3732Mr.C.L.Millerfromtheplantdesign,therebyeliminatingtheapparentbasisforthetemperaturebasedisolationfunction.AlicationtoRHRShutdownlin:AfeatureoftheoriginaldesignwhichhasresistedexplanationwasthatthesteamtemperaturederivedsetpointsandisolationfunctionswereappliedtotheisolationfunctionfortheRHRshutdowncoolingsuctionvalves.Therefore,ourthermalanalysesusedleakageofreactorcoolantatprocesstemperaturesexistingwhenRHRshutdowncoolingwouldbeonline.Forconservatism,weusedatemperatureof212'F.ThiswaswithinthebandofpossibletemperaturesfortheReactorCoolantSystem(RCS)whenRHRshutdowncoolingwasinoperation,buthotenoughthatsomeoftheleakingfluidwouldflashtosteamuponescapeandbeapparenttothetemperaturedetectioncircuits.Webelievethatusingthe212'Fnumberismoreconservativethanusingtheupperendofthebandinthattheroomthermalresponseisreducedwiththelowerdrivingtemperature,anditwouldtakelongerforthetemperaturecircuitstofunction.Usingthelowestendofthebandat200'FwouldnotbecompatiblewiththeCOTI'APthermalanalysesmodel.ncceilitof5PMan2PMeBaEarlyCOTI'APanalysesdemonstratedthattheoriginal5gpmleakbasisforsetpointselectionwasnotsupportedbypresentanalyticalmethods.SeePLA-3630whichprovidedjustificationfortheuseof25gpmleakageasananalyticalbasisforsetpointselectionforotherECCSroomsinwhichtemperaturebasedsteamleakdetectioncircuitrywasused.IntheRHRareahowever,theCOTTAPthermalanalysesatleakratesof25gpmcouldnotbeshowntosupporttheexistingTechnicalSpecificationsetpointswithinareasonabletimeframe,andstatedthisinourfirstsubmittal,PLA-3485,1/14/91,Wecalculatedroomtemperatureafter24hoursofa25gpmleakanddefinedthatastheAllowableValueforuseinoursetpointcalculations.Wefoundthatforthewinterconditioncase,thetemperaturessetpointswouldhavetobereduced24'Fto33'F.TheresultantsetpointswouldbeveryclosetothepostLOCAdesignmaximumtemperaturesforthearea.TheywouldnotprovideadequatemarginandcouldresultininadvertentisolationswhenavailabilityofRHRshutdowncoolingcouldbeveryimportanttoplantsafety.FifandneHundredPMWealsousedCOTTAPtodeterminetheroomthermalresponsewithleakratesof50gpmand100gpm.Forthe50gpmcase,theresultantroomtemperatureatthefourhourpointwas165'F.Usingestablishedsetpointmethodology,amarginof22'FwascalculatedbetweenthemaximumpostLOCAtemperatureandthetripsetpoint.Becausethe FILESR41-2/A17-2PLA-3732Mr.C.L.Milleras-installedsetpointisalwaysprovidedwithadditionalmargintoavoidinstrumentdriftbeyondtheAllowableValue,actualmarginisfurtherreduced.Wedonotconsiderthismargintobeacceptableforpotentialunnecessarylossoftheshutdowncoolingfunction.Forthe100gpmcase,theresultantroomtemperatureatthefourhourpointwas184'.Againusingestablishedsetpointmethodology,thecorrespondingTripSetpointwouldsatisfytheexistingTechnicalSpecificationTripSetpointof167'F.Thebasisforthedecisiontodeletethefunctionincludedthelowincrementofadditionalsafetyprovidedbytheautomaticisolation,andthelargerpotentialdecrementinsafetycausedbyretentionofthefunctionatalargerdesignbasesleakage.TimDrinWhichAuomticIlinWldBFninl:Theactualtimeduringwhichtheisolationcircuitrywouldfunctiontoisolatealeakisverysmall.LimitsaredeterminedbyRCSconditionsof98psig(336'Ftemperature)and0psig(200'Ftemperature).Theupperlimitissetbythehighpressure/lowpressureinterlockwhichallowsRHRShutdowncoolingtobeunisolatedonlywhenreactorsteamdomepressureislessthan98psig.ThelowerlimitreflectstheTechnicalSpecificationrequirementsthatsteamleakdetectionautomaticisolationfunctionsareonlyrequiredtobeoperableinstartup,hotshutdown,andrunmodesofoperation(i.e.,whentheRCS.temperatureisgreaterthan200'F.)TheconditionwithRCStemperaturesbetween200'Fand336'Fisusuallyjustashortdurationtransientconditionwiththeplanttraversingbetweenhotandcoldshutdown.Thusthetimeinwhichthecircuitrycouldperformitsintendedfunctionisverylimited.11TimeInWhichimentMalfunctinneFMisactuaion:,Thetimewindowismuchlargerthanaboveinwhichatransientormalfunctioncouldupsetthesteamleakdetectioncircuitryandcauseanunnecessaryisolationwithshutdowncoolingsysteminoperationtomaintaincoretemperaturesbelow200'F.Thesetransients/malfunctionscouldoriginateintheelectricaldistributionsystem,HVACsystem,orinsurveillanceandpreventivemaintenanceinducedtransients.Shouldoneofthesetransientscauseanautomaticisolation,thepotentialforanundesiredRCStemperaturetransientoutsideofthecoldshutdowntemperaturebandishigh.SuchatransientwouldrequireinitiationoftheSSESemergencyplan,exercisingbothin-plantandout-of-plantresponseteamsandwouldconstituteanunnecessarychallengetoplantsafety.

FILESR41-2/A17-2PLA-3732Mr.C.L.MillerIfthetransientsormalfunctionsweretoinitiateaninappropriateisolationcircuitactuationduringthetimeinwhichtheplantwereatpower(RHRShutdownCoolingisolated),theaboveconsequenceswouldnotbeapplicable.However,reportinganddocumentationrequirementswouldremain.hernideratin:Weconsideredtheprocessofleakdevelopment.Mostleakswouldstartsmallandgrowoverlongperiodsoftime.Webelieveitimprobablethataleakcouldprogresstovaluesclosetothe100gpmleakratewithoutdetectionbyinstrumentationalarmsorbyplantstaff,Includedinthesemeanswouldberoomflooddetection,arearadiationmonitors,temperaturealarms,andactualRHRroomtemperaturesreadinthecontrolroom.OuroriginalproposalinPLA-3485statedthatdeletionoftheautomaticisolationfunctionwouldnotincludedeletionofthetemperatureindicationandalarmfunctionspresentlyassociatedwiththeisolationfunction.;Thesefunctionswouldberetained.SeeourresponsetoRequestNo.5.Wealsoconsideredretentionoftheisolationfunctionwithenabling/disenablingswitchestoensurethattheisolationfunctionwasonlyoperableinthesmallperiodoftimeinCondition3whiletraversingbetweenthehighpressure/lowpressureinterlocktemperatureandcoldshutdownlimits.Weconcludedthatthisapproachwouldnotbebeneficialinthatitwouldnotimprovethesensitivityofthecircuitrytopotentialleaks,itwouldunnecessarilycomplicateplantdesign,promotepotentialpersonnelerrorandpossibleESFequipmentmisoperationormalfunction.AsstatedinRegulatoryGuide1.45RCPBLeakageDetectionSystem"itisnotnecessarythatallleakagedetectionsystemsbeemployedinaspecificnuclearpowerplant.However,sincethemethodsdifferinsensitivityandresponsetime,prudentselectionofdetectionmethodsshouldincludesufficientsystemstoassureeffectivemonitoringduringperiodswhensomedetectionsystemsmaybeineffectiveorinoperable.Someofthesesystemsshouldserveasearlyalarmsystemssignalingtheoperatorsthatcloserexaminationofotherdetectionsystemsisnecessarytodeterminetheextentofanycorrectiveactionthatmayberequired."InlinewiththephilosophyoftheRegulatoryGuidetheuseoftemperaturemonitoringasamethodofisolationiseffectiveandappropriatewh'enusedinconjunctionwithhighenergylinessuchasRWCU,HPCI,RCIC,andmainsteam.Itisineffectivewhenusedforlowerpressure/temperaturelinessuchastheRHRshutdowncoolingmodebecausedetectionwouldrequireleakageratesofgreaterthan90gpmexistingforuptofourhours.AsstatedinPLA-3485,theinadequaciesofthesystemforautomaticisolationwouldnotimpactonitsuseforroomtemperaturemonitoringandalarmatlowerleakagerates. FILESR41-2/A17-2PLA-3732Mr.C.L.MillerWithouttheconsequencesofunnecessaryisolationactuation,marginscouldbereducedresultinginmanualdetectionandalarmoflowerleakagerates.PP&LisfollowingtheguidanceoftheRegulatoryGuidebymaintainingthehightemperaturealarmfunctionandutilizingflooddetection,arearadiationmonitorsandoperatorroundstomonitorforleaks.TheseleakdetectionmethodsaredescribedindetailinresponsetoRequestNo.5.WebelievethatconsiderationoftheissuesasexplainedhereinandinouroriginalsubmittalPLA-3485providethedetailtojustifythedeletionofthisfunction.REUETNO3Thestaff'scopyoftheFSARforSusquehannahasnotbeenupdatedforsometimeandtheinformationregardingRHRoperationmaynotbecurrent,Inordertofacilitatethestaff'sreview,adetaileddescriptionoftheRHRsystemandoperatingmodesshouldbeprovided.R~esoose:AnupdatedcopyoftheFSARforSusquehannawasrecentlyprovidedtotheProjectManagerfortheStaff'suse.Section5.4.7providesadescriptionofthemodesoftheRHRsystem.REUETNO.4DetailsoftheRHRpumproomtemperatureanalysisshouldbeprovidedforstaffreview.Detailedinformationrelatedtotheapplicationofcomputercodesshouldalsobeprovidedunlessthestaffhaspreviouslyreviewedandapprovedthecodeforthespecificapplicationinquestion.Inanycase,allassumptionsusedintheanalysisshouldbeidentifiedandfullyexplained.~Resoose:PP&L'ssubmittaltotheNRC,PP&LletterPLA-3630datedAugust19,1991,onTemperatureLeakDetectionRWCU/HPCI/RCICcontainedtheuser'smanualfortheCOTTAPcomputercodeandacopyofapaperrecentlypublishedinNuclearTechnologywhichdescribesthemethodologyusedintheCOITAPprogramandpresentssomeoftheverificationcalculationswhichhavebeenperformed.Theuser'smanualpresentssomeofthecalculationswhichwereperformedagainstproblemsthathave.exactanalyticalsolutions.ThereferredpaperpresentsthemethodologyalongwithcalculationswhichhavebeenbenchmarkedagainstcalculationsperformedwiththeCONTEMPTcomputerprogram.Inaddition,theprogramandcomputationpackagehavebeenindependently FILESR41-2/A17-2PLA-3732Mr.C.L.MillerreviewedbyGilbertAssociates.PP&LalsomaintainsaQualityAssurancefile/packagefortheCOTTAPcomputercode.PP&Lhasnotresubmittedthisinformationwiththisrequestforadditionalinformation.AttachmentBcontainsasummaryofthecalculationswhichwereperformedfortheRHRPumpRoomanduponwhichthesetpointdeletionswerebased.Calculationswereperformedunderavarietyofconditions(forexample,summerandwinterinitialconditions)andhavebeenindependentlyreviewed.AttachmentBalsocontainstheCOTTAPresultsfora50gpmand100gpmleak.Theattachmentpresentsasummarywhichincludesthemethodologyandassumptionsforeachcalculationalongwiththerepresentativeresults.REVESTN.Thelicenseehasdiscussedactionsthatcanbetakeninlieuoftheautomaticisolationfunction,butcompletedescriptionofspecificactionsthatwillberequiredandhowtheserequirementswillbeimplementedhasnotbeenprovidedforstaffreview.Thequalification,qualityclassification,surveillancerequirementsandsingle-failureaspectsofequipmentsuchasthesumplevelinstrumentandannunciatorshavenotbeendiscussedanditisnotcleartowhatextentthisequipmentcanbereliedupontofunction.Additionally,therewasnodiscussionrelativetoASMECoderequirementsandhowtheserequirementswouldbesatisfied.~Resoose:Deletionofthehightemperature,automaticisolationfunctionfromtheRHRShutdownCoolingmodeofoperationwillrequireoperatoraction.Alternativeleakdetectionmethodsandtheirutilizationarediscussedbelow.1.0~AITherearethreehightemperaturealarmsinthecontrolroom:RHRLeakDetectionHiTemp,RHRLeakDetectionLogicAHiTempandRHRLeakDetectionLogicBHiTemp.1.1RHRLeakDetectionHiTempThisalarmisinitiatedviaRHRpumproomhighambientordifferentialtemperaturedetection.ThesettingislowerthanthepresentTechnicalSpecificationisolationsetpointtoalertOperatorsearlyonofpotentialoffnormalconditions.OperatorresponseiscoveredbyalarmresponseprocedureAR-109-001.Specificoperatoractionsare:

FILESR41-2/A17-2PLA-3732Mr.C.L.Millera.DeterminewhatproducedthealarmbyobservingtemperaturerecorderslocatedintheControlRoom.b.C.Checksystemforleaks.CheckReactorBuildingventilationsystemforproperoperation.Therearenoautomaticactionsresultingfromthiscondition.ThesystemutilizesaClass1Etemperatureelementandanaffiliatedcabletoanon-Class1Etemperaturerecorderwithinputintothenon-class1Eannunciatorsystem.RHRLeakDetectionLogicAHiTemp/RHRLeakDetectionLogicBHiTempThisalarmisinitiatedviaRHRPumpRoomhighambientanddifferentialtemperaturedetection.ThealarmsaresettopickupinaccordancewiththepresentTechnicalSpecificationisolationsetpoints.ThetemperaturemonitoringsystemisdivisionalizedineachRHRpumproom.ThesystemutilizesredundantClass1Etemperaturedetectors,switches,cableandracewaywithinputsintothenon-class1Eplantalarmsystem.OperatorresponseiscoveredbyalarmresponseprocedureAR-109-001.Proposedoperatoractionswithdeletionoftheautomaticisolationfunctionare:a.Checkpanel1C614inControlRoomtodeterminesourceofhightemperatureorhighdifferentialtemperature.b.Checktemperaturemoduleforproperoperationandalarmsetpoint.C.Checksystemforleaks.d.CheckReactorBuildingVentilationSystemforproperoperationinaccordancewithOP-134-002.

FILESR41-2/A17-2PLA-3732Mr.C.L.MillerF'I2.2i~IDLevelinstrumentationisprovidedineachofthedivisionalizedRHRPumpRooms.Theinstrumentationisnon-class1E.Levelindicationwilldetecta50gpmleakinabout90minutesanda100gpmleakinabout45minutes.OperatorresponseiscoveredbyalarmresponseproceduresAR-109-001.Specificoperatoractionsare:'I~Perform,off-normalprocedure,ON-120-001,FloodinginReactorBuilding.~'-Dispatchoperatortoassessextentanddeterminesourceofflooding.~Isolatesourceoffloodingasrapidlyaspossible,unlesssourceisrequiredtoshutdownreactororassureadequatecorecoolingorsuppressafire.~FollowtheremainingstepsinON-120-001.Againthefloodingprocedurerequirestheoperatortoassessandmanagetheleakrelativetoassuringadequatecorecooling.Thisisin-linewiththepositiontodeletetheautomaticisolationfunction.3.0AmticTIinFreThefollowingaretheadditionalautomaticisolationfeaturesfortheRHRsystemintheshutdowncoolingmodeexcludingthetemperaturedetectionfeatures:Reactorvesselwaterlevelsignalwillisolatethesystemifthevesselleveldropsbelow13.0inches.Reactorvesselpressuresignalwillisolatethesystemifthevesselpressureexceeds98psig.RHRflowsignalwillisolatethesystemiftheflowisgreaterthan25,000gpm.4.0erRndInaccordancewithoperationsprocedureOI-PL-0161theoperatormustentertheRHRpumproomtocheckbearingoillevelsevery6hours.Ifaleakweretooccurbeforethehightemperatureorflooddetectionalarmsactuatedtheoperatorwouldidentifytheleakduringrounds. FILESR41-2/A17-2PLA-3732Mr.C.L.MillerRelativetotheASMECoderequirements,theSusquehannaSESISIManualwhichisbasedon'ASMESectionXI,definestheplantspecificpipingandcomponentinspectionrequirementsandthefrequencywithwhich'"theISIisperformed.FortheRHRlines,aleaktestisperformedeveryother'utagetoidentifypotentialareasofpipedegradation.Asurfaceandvolumetricweldexamisalsoperformedeverytenyearstoidentifypotentialwelddefects.1Ifaleakweretooccur,theoperatorwouldassessandmanagetheleakandweighitsseveritytotheimportanceofprovidingadequatecorecooling.ThefaultypipewouldberepairedinaccordancewiththeASMESectionXIrepairandreplacementrequirements.TherepairwillbeinspectedinaccordancewithASMESectionXI.Priortostartup,anevaluationoftheleakseffectonotherareaequipmentwillbeconductedandappropriateactiontaken.Thesteamleakdetectionsystem(ambientanddeltatemperature)atSusquehannaSESisnotrequiredbytheASMECode,norisitusedtoshowcompliancewiththeASMECode.REZTThelicensingbasisassumesthatleaksfromthereactorcoolantsystemwillbeisolatedinashortperiodoftime.Withouttheautomaticisolationcapabilityinplace,adetailedanalysisoftheradiologicalconsequencesofacoolantleakoutsideprimarycontainmentmustbecompletedandsubmittedforstaffreview.Resp'~:Forthegreatestpartofplantlife,RHRisisolatedfromthereactorcoolantsystembytwoisolationvalvessubjecttoahigh/pressure/lowpressurepermissive.Thenextgreatestpartofplantlifeisspentincoldshutdownwhensteamleakdetectionisnoteffectiveandisnotrequired.Onlyasmallportionofplantlife(atransientcondition)isspentwiththeRHRshutdowncoolingisolationfunctionbeingon-lineandreadytooperate.Inthisperiod,onlineinstrumentsareavailabletowarnofareactorcoolantsystemleak.Ifaleakweretooccur,installedinstrumentsandoperatorobservationwoulddetectthatleakbefore10CFR100limitswerereached,andbeforeleakageratescouldapproachthe100gpmvalue.Actionwouldberequiredtoisolatetheleak.Thisconclusionwouldholdregardlessofwhetherthepresentlyinstalledsteamleakdetectionisolationfunctionswereretainedorremoved.TheradiologicalconsequencesofacoolantleakoutsideprimarycontainmentwereanalyzedinPP&LcalculationSE-B-NA-078.Fiftygpmofreactorgradewaterwasassumedtoleaktosecondarycontainmentataconcentrationof4.0uCi/gmDose FILESR41-2/A17-2PLA-3732Mr.C.L.Miller.EquivalentIodine-131.ThisisthemaximumallowablecoolantconcentrationofiodineforSusquehannaSESoperation.Nocreditforremoval,holdupordecaywastaken.Theperiodoftheleakwasassumedtobe48hoursafterwhichenvironmentalleakagewasterminated.Theanalysisconcludesthattheresultantoffsiteandcontrolroomdosesfallfarbelow10,CFR100offsitedoselimitsand10CFR50,AppendixA,GDC-19controlroomdoselimits.AnanalysisofareactorsteamleakwasalsoconductedinPP&LcalculationFX-C-DAM-010.A50gpmwaterequivalentsteamleakwasassumedtooccurfora24hourperiod.Nocreditforremoval,holdupordecaywastaken.Thisanalysisalsoconcludedthattheresultantoffsiteandcontrolroomdosesfallfarbelow10CFR100offsitedoselimitsand10CFR50,AppendixA,GDC-19controlroomdoselimits.CalculationsSE-B-NA-078andFX-X-DAM-010whichdocumenttheradiologicalanalysiswereincludedinPP&L'sletterPLA-3630datedAugust19,1991ontemperatureLeakDetectionRWCU/HPCI/RCIC.Basedonthecalculation,evenifa100gpmleakof'reactorcoolantwereallowedtocontinuefor24hours,theresultant'offsiteandcontrolroomdosesfallfarbelow10CFR100offsitedoselimitsand10CFR50,AppendixA,GDC-19controlroomdoselimits.Itisnotexpectedthataleakatanyrate,wouldcontinueforanextendedperiod.(greaterthan4hours)withoutisolatingshutdowncooling.Ifyouhaveanyquestions,pleasecontactMr.C.T.Coddingtonat(215)774-7915.Verytrulyyours,H.W.KeiserAttachmentcc:NRCDocumentControlDesk(original)NRCRegionIMr.G.S.Barber,NRCSr.ResidentInspectorMr.J.J.Raleigh,NRCProjectManager ATTACHMENTAF9203090230.'

SusquehannaSteamElectricStationSteamLeakDetectionIssues II5 AGENDAIntroductionC,T.CoddingtonMariagementPerspective',l.IIDiscussionofIssuesF.G.ButlerD.J.CardinaleandJ.C.E:night RxBldgMSTunneldTInopNOTIFICATIONPROBCORRMNGMNTPLANGENERICWALKDOWNSMODStCODEDVLPMT~DESIGNBASISROOTCAUSEQUESTIONAIRECHANNELCHK7/27/888/889/88 ROOMTHERMALMODELSSTEAMTUNNELCOOLERMODELLEAKRATEASSMNTSSETPOINTCALCSTECHSPECFSARCHANGESPRESSURETEMPERATURERESPONSEPLANTMODS3/896/909/901/912/91

RxBldgMSTunneldTlnopNOTIFICATIONIPROBCORA)MNGMNTPLANGENERICWALKDOWNSMODSICODEDVLPMTtDESIGNBASISIROOTCAUSEQUESTIONAIRECHANNELCHKROOMTIIERMALMODELSLEAKRATEASSMNTSPRESSURETEMPERATURERESPONSESLII'()INI(AL(:S1LCII!il'LlAII(.'IIAN(il.SI'LANTMODSJISII.AM1UNNLLOOLIIIMODLI.7/27/888/889/883/896/iJ()iJ/iJ()I/iJI'/iJI MANAEMENTACTIONTEAMMANAGEMENTDESIGNI&CMAINTENANCESSESTECHNICALSTAFFCOMPIIANCELICENSINGANALYSISOTHERSASREQUIRED-RADIOLOGICALEQPARTSREREAPLIEDBECHTELGEERALELECTRICORIGINALA/ETHERMALCALCULATIONORIGINALSETPOINTCALCULATIONDESIGNBASISCONFIRMATIONCRITICALCRACKSIZEANALYSISGILBERTCOMMONWEALTH-TUNNELTHERMALMODELVERIFICATIONAIRCOOLTUNNELCOOLERMODEL P

ORIGINALDISCOVERY:July27,<988CONDITIONDISCOVERED:REACTORBUILDINGMAINSTEAMTUNNELBOTHUNITSAFFECTEDFOURTRIPCHANNELSPERUNITDIFFERENTIALTEMPERATUREISOLATIONTRIPFUNCTIONINOPERABLE"HOT"AND"COLD"LEGTEMPERATUREELEMENTLOCATlO'NSREVERSED

'4 INIMEDlATEACTlONS:PROMPTMANAGEMENTATTENTIONANDACTIONPLANNINGPROMPTNRCNOTIFICATIONINSTRUMENTSREWIREDTOREVERSEDIRECTIONOFDELTA-TSIGNALRESTOREINSTRUMENTOPERABILITYDEFINEAIVIANAGEMENTTEAMTO-DETERIVIINECAUSE(S)-REVIEWTHEDESIGN,ANDWALKDOWNALLOTHERSLDTENIPERATURESENSORSFORRELATEDPROBLEMS-IMPLEMENTCORRECTIVEACTIONSFORSHORTTERIVIPROBLEMS-IMPIEMENTACTIONPLANSFORLONGERTERMPROBLEMSPARTICIPANTSINTEAMTOINCLUDE:MANAGEMENTDESIGN-.STATIONTECHNICALSTAFFOPERATIONSLICENSINGANDCOMPLIANCEMAINTENANCEOTHERSASREQUIRED Qflg CORRECTIVEACTIONITEMS:-PERFORMDESIGNBASISANALYSESOFROOMTHERMALRESPONSETOSTEAMLEAKSASIDENTIFIEDINFSAR.-ASSESSLOCATlONSOFOTHERTEMPERATUREELEMENTSANDCORRECTPROBIEMSWHEREFOUND.-ENSUREADEQUATEINSTALLATIONINSTRUCTIONSAREPROVIDEDINMODIFICATIONPACKAGESFORTEMPERATUREELEMENTINSTALLATION-ASSESSVALUEOFDELTA-TINSTRUMENTSFORISOLATIONOFSTEAMLEAKS,ANDCOORDINATETHISACTIVITYWITHTHEBWROG.QUESTIONNAIRESURVEY,OPERATIONSANDI8cCMAINTENANCESTAFF.-ROOTCAUSEANALYSIS-CLEARLYASSIGNEDSLDSYSTEMRESPONSIBILITIES-IDENTIFYNORMALVALUESFORVARIANCECHECKS-EVALUATERECORDINGANDRETENTIONOFDATADURINGDAILYCHANNELCHECKACTIVITIES.

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OTHERCONSIDERATIONS-PROMPTNRCREPORTING-ENFORCEMENTCONFERENCE88-226,DATED9/30/88-REGULARANDONGOINGCOMMUNICATIONWITHNRC-INDUSTRYFOREFRONTINPROBLEMIDENTIFICATIONANDRESOLUTION-EARLYANDCONTINUOUSDIALOGWITHNSSSSUPPLIER-INDUSTRYFOREFRONTINROOMTHERMALRESPONSECODEDEVELOPMENTCOTTAP:COMPARTMENTTRANSIENTTEMPERATUREANALYSISPROGRAM-FORMALSETPOINTCALCULATIONMETHODOLOGY-ALLINCLUSIVEPROGRAM,DESIGNANALYSESCOMPLETED,WITHRECOMMENDATIONSDEFINED,JUSTIFIED,ANDDOCUMENTED.

IIc$V SENSORPLACEMENTSTEAMLEAKDETECTIONSYSTEMPROBLEMSSYSTEM/AREAUNIT2RxBLDGMAINSTEAMTUNNELPROBLEMSENSORSINSTALLEDREVERSEDDELTA-TMONITOREDACROSSCOOLERSACTIONSOOR1-88-205.DCP88-9023CORRECTEDPROBLEMBYREVERSINGLEADSNCR88-0554.DCP88-9024RELOCATEDTE'STOVENTINLETS.NIT2HPCIROOMDELTA-TINLETTE'SNOTFULLYINCOLDAIRINLET.NCR88-6062.DCP88-6057RELOCATEDHVACINLETDUCTFLANGE.(ECO)UNIT1RxBLDGMAINSTEAMTUNNELUNIT1RWCUAREASENSORSINSTALI.EDREVERSED.PUMPROOMHIAMBTEIOCATEDINCORRECTLY.SOOR1-88-0598.DCP88-9022CORRECTEDTHEPROBLEMBYREVERSINGWIRES.NCR88-0598.DCP88-9030RELOCATEDTE.PUMPRMDELTA-TTELOCATEDINLESSSENSITIVEAREATHANDESIRED.DESIGNBASISTHERMALCALCS.DCP90-9036RELOCATEDTETOMEASUREONLYPUMPROOMEXHAUSTTEMPERATURE.PENETRATIONRMSENSORLOCATEDINPUMPROOM.NCR87%484.DCP87-9215RELOCATEDTE.

STEAMLEAKDETECTIONDESIGNBASISREGULATORYREFERENCESGDC30:REQUIRESTHATibiEAi4SBEPROVIDEDFORDETECTINGAND....IDENTIFYINGLOCATIONOFREACTORCOOLANTLEAKAGE.REGGUIDE1.45LEAKAGEIDENTIFICATION&MEASUREMENTDRYWELLSUMPLEVELORFLOWTWOOFTHREEOTHERTYPESPARTICULATENOBLEGASTEMPERATUREBASEDISOLATIONSYSTEMSNOTSPECIFICALLYDISCUSSEDSRP(5.2.5)REFERENCESGDC30ANDR.G.1.45ASCONTROLLINGDOCUMENTSFORDETECTION,IDENTIFICATIONANDMONITORINGOFREACTORCOOLANTLEAKAGE.

1,',I0P~~i'I1 ECCSROOMSLDDESIGNBASISSSESREFERENCESFSAR:5.2.5.1.3definesthebasisforHPCI,RCIC,andRHRSLDsystems--setpointsarekeptlowenoughtoallowtimelydetectionofa5gpmleak.(doesnotdefinethebasisforRWCU,northeMainSteamTunnel)-setpointsincludesufficientmarginabovepostLOCAmaximumareatemperaturestoprecludeinadvertentisolationsignals.SER:5.2.5-notesthattemperaturesensingsystemsareinstalled.-concludesthatleakagedetectionsystemsprovide.reasonable:assurancesTECHSPECSBASIS3/4.3.2-IsolationActuationInstrumentationSetpointsareestablishedatalevelawayfromnormaloperatingrangetopreventinadvertentoperation.

ECz ESTABLISHINGDESIGNBASISFSARSEARCHES-.'sparrowwindowforsetpointselectionBECHTEL(A/E)CALCULATIONREVIEWS:-SimplifiedModel-NoHeatLoss,RapidHeatUp-Setpointsselected:-withlargetolerances-similartopreviousBWRs-belowfireprotectionsystemsetpointsGECompany(NSSS)StudyEffort-5gpmvs25gpmbasis-25gpmcurrentdesign,BWR4design

,.tgr,q INITIAL0EVELOPME'.iT1.RECONCILIATIONOFFSAROBJECTIVES2.ROOMTHERMM,ANALYSES-%'interConditions-SummerConditions3.COTTAPCODEDEVELOPMENT-EnergyBalance-MassBalance-SingleNodeModel

SLDTHERMALMODELORIGINALDESIGN SLDTHERMALMODELCOTTAPDESIGN COTTAPCompartmentTemperatureTransientAnalysisProgramAcomputercodetopredictenvironmentalconditionsincompartmentsseparatedbyuniformwalls.Thecodesolvestransientheatandmassbalanceequationstodeterminetemperature,pressureandrelativehumidity.Theone-dimensionalheatconductioniscalculatedforeachslabtocomputeheatflowbetweenrooms.Userinputsincludephysicalandgeometricdata,steamleakconditions,flowpathdataandinitialconditions.

DESIGNBASISLEAKAGERATEProblemtatement:FSARRequires~,Setpointshavesufficientmargintoprecludeinadvertentisolation~Setpointsbelowenoughtoallo~timelydetectionofa5gpmleakCalculationsshow~Setpointsconsistentwithdetectionof5gpmcouldcauseinadvertentisolation HPCIROOMTEMPERATURERESPONSE(WINTER)260~,200(3.DUJK:150I-CL100eo--01015TIME(HRS)I20I25LegeI>dg'bOS'LtI/p5CPMlbOLAl>OHbtIf'OIHI TEMPERATURESETPOINTCALCULATIONRESULTSHPCIRoomA,IIBIE,iTEvistineCalculatedDIFFERENTIALEvistinoCele.:ta!e.:.AnalyticalLimitAllowableValueTripSetpointProcessSetpointRCICRoomAnalyticalLimitAllowableValueTripSetpointProcessSetpointHPCI/RCICpipingAreaAnalyticalLimitAllowableValueTripSetpointProcessSetpoint+itA174167160N/A174167159N/A174167160201194188182230223217211191184178]72M/A988986N/A988986N/A988986I"l11631071471g'l1391331051009793 PROPOSEDL$DXDETECTIONSETPOINTCK-'&CAGESHPCIRoomAMBIE'.4TExisrin~COOLERI'.iLET~ExisrioP~roosedAllowableValueTripSetpointProcessSetpointRCICRoomAllowableValueTripSetpointProcessSetpoint174167160174167160154147140154147140174167160174167160 Il,j(Wl SAFETYAEME.v'T25gpmleakratebasisallowstimelydetectionofleakagewithoutriskofinadvertentisolation25gpmbasisisconsistentwithGEdesignSpecandwithbasisusedforotherBWR'sandacceptedbyNRCLeakDetectionSystemcontinuestoconformtorequirementsofGDC30andReg.Guide1.45TechSpecchangesprovideadditionalmargintoassureHPCI,RCICandR%CUsystemswillnotinadvertentlyisolateOtherredundantleakdetectionsystemscontinuetoperformtheirsafetyfunction "a',PIlgglt.U4V"ip DELETIONOFSTEAMLEAKDETECTIONSLDISOLATIONFUNCTION-RHRROOM(TSCHANGEO220)PROBLEMSTATEMENT:DesignPhilosophyofSLDisNot'onsistentinRHRRoom~ExistingRHRRoomTemperatureSLDIsolatesShutdownCooling(SDC)~SetpointsBasedonLeakagefromSteamCondensingMode~SLDinRHRRoomNotEvaluatedasPartofRemovalofSteamCondeasiagModeLoweringSetpointsCreatePossibilityQfInadverteatIsolatioaofSDCCoaflictingDesignDocumeats~GEDesigaSpec-AlarmOaly~FSAR-AlarmOnly/Alarm-Isolation~TS-Alarm-Isolatioa RHRPUMPROOM(I-14.104)HEATUPEVALUATION(25GPMWATERLEAK/WINTER)-160.140(3Lall20:-LJI-w~100CLLLII-80-601015'IME(HRS)20I25

.5)ig4 TEMPERATURESETPOINTCALCULATIONRESULTSRHRRoomAilfBIENT~is~t'alculatedDIFFERENT!AL~v~tCalcuatedAnalyticalLimitAllowableValueTripSetpointProcessSetpointN/A170.5167156147140134128N/A90.5898673706763 f,y1I~%S't SAFETYASSESSMENTRedundantSystemsAdequatetoDetectLeaksinSDCTemperatureAlarms,FloodAlarmsandManualIsolationsSatisfyNeedtoDefect/ControlLeakageinRHRRoom~ManualIsolationReducesNetRiskofIsolatingSystemUnderNon-LeakConditionsConsequenceofOperatingSDC~ithSmallLeakMaybeLoserThanConsequenceof.LosingDecayHeatRemoval 7h, REACTORBUILDINGMAINSTEA.'vfTUNVELPROBLEMSTATEMENT:OriginalcalculationsshowedexistingTechSpecsetpointsareinconsistentwiththedesignbasisconditions.Coolerperformanceisdifficulttomodelduetovariationsinrelativehumidityandlatentheatremoval.Latestcalculationsproducesetpointsconsistentwiththedesignbasis.

,CV CALCULATIONPROCESSOriginalmodelusedsimplecoolermodel(neglectinglatent~~cooling)andnoroompressurization.Modelwasrefinedtointegratecoolermodel(varylatentheatremoval)andtoincludepressurization.Conservativeinterpretationof"25gpmwaterequivalent"waschangedtomatchbasisusedfordr@veilleakage.

STEAMTUNNELTEMPERATURERESPONSE(WiNTER)200180C9LLl-Q160CC.140CL1Z010001015TIME(HRS}I2025Legend~40Cf'M(J"5GVM'iso'.Aviv~stirvi~<

STEAMTUNNELHEATUPEVALUATION(25GPMEQUIVALENTSTEAMLEAK/WINTER)200180C34J.160LLJ43140CLLJt-'2010001510TIME(HRS)I1I20I25 IAITI.MCAJ.CULATIOYfRESULTSAmbientTemperatureSetpoints~Evistin25gpm50gpmalculatedCalculatedAnalyticalLimitAllowableValue.TripSetpointProcessSetpointN/A184177174166159153150191184178175DifferentialTemperatureSetpointsQdsti~n25gpm50gpmalculatedCaculatedAnalyticalLimitAllowableValueTripSetpointProcessSetpointN/A108999690858280'0910410199 P01*

PRESENTCALCULATIONRESULTSAmbientTemperatureSetpoints~Ev'ski~C~id'IIdAnalyticalLimitAllowableValueTripSetpointProcessSetpointN/A184177174184177174168187180177171DifferentialTemperatureSetpointsF~x'stagCalcuared'alculated-'nalyticalLimitAllowableValueTripSetpointProcessSetpointN/A108999610910410297109104102971.Interpolatedtemperaturefrom9300&;14,800lb/hrcalculations.2.Calculatedtemperaturefor12,500lb/hrleak.

ASSESSME,'-iTCalculatedsetpointsconfirmtheexistingsetpointsareconsistentwithdetectionofleaks25gpmorgreater.Resultsarewithinthemarginoferrorofthemodel.NochangeisrequiredtotheexistingTechSpecsetpoints.

t TURBINEBUILDINGMAINSTEAVfTU'NOELDELETIONOFHIGHTEAPERATL'REISOLATION,PROBE.E~!STATEWiE.'v'TSoExisitinsetpintsarenotadequatetodetectandisolatea25gpmleak.eTheexistingsystemdoesnotprovidesufficientprotectionagainstfalseisolation.~Detectioncapabilityishighlydependentonleaklocation.~Thesteamtunnelisnotacosedvoueanddoesnotfitthebasisfortemperaturemeasurement.~Analyzingthetunneltoestablishreliablesetpointsrequiresacomplex3Dmodelbeyondtheodellincaabiliofavailablecomputercodes..~Temperaturealarmsandedetectioethodsusedelsewhereintheturbinebuildingareadequatetodetectandcontrolleakage.

TURBBLDGSTMTUNNELEVALUATION(25GPMEQUIVSTMLEAK/WINTER)150140-C3IJJ"C3LJJ150lYLJCLI-12011001015TIME(HRS)2025 h~VI>>,J~

RISKOFFALSEISOLATIONTheexistingsetpointsprovideinsufficientmargin(lessthan25'F)abovethenormalmaximumtemperature.TemperatureincreasesalongthelengthofthetunnelandTE'sarelocated'inthehighesttemperatureareaofthetunnel.Temperaturesupto150'Fhavebeenobservedwithnormal,non-leakconditions.Temperatureshavereachedthe157'Falarmsetpointduetosmallpackingleaksandventilationsystemdisturbances.

CIri:~'Dlg/ilLEAKDET=:pip~-~~c tA'VIgl4\yIts LEAKLOCATIONLeakageatthefarendofthetunnelfromtheTE'swillbedilutedandmasked.LeakageneartheTE'sisundilutedandhasanamplifiedeffectonmeasuredtemperature.LeaksdownstreamoftheTE'swillnotbedetected.

~1~ClI

CLOSEDVOLUVIETheopenendofthetunnelal1owsuncontrolledf1owintoandoutofthetunnel.TheeffectofthisHowpathontemperaturemeasurementandleakdetectioncapabilityisunknown.Temperaturemeasurementshouldbeusedinaclosedvolumetoeffectivelydetectleakage.FSAR5.2.5.13-"piping...isinstalledincompartmentsorrooms...sothatleakagemaybedetectedbyareatemperaturemeasurement."

TEMPERATUREMODELLINGCAPABILITYTheconfigurationofthetunnelcausesdifficultyincreatingatemperaturemodel.COTTAPislimitedtocalculatingaveragetemperaturefortheroomvolume.Thetemperaturegradientandflowpatternscannotbeaccuratelymodelledwithavailablecomputercodes.

LEAKDETECTIONMETHODSMainsteamlineselsewhereintheturbinebuildingarenotmontitoredbyleakdetectioninstruments.Radiationalarms,visualobservationprovideadequate.detectioncapability.Temperaturealarmsforthesteamtunnelwillberetained.

I' SAFETYASSESSME'NT~Deletingtheautomatichightemperatureisolationsignalreducestheriskofinadvertentmainsteamlineisolation.~Reliableisolationsetpointscannotbeestablishedtoprovidesufficientprotectionagainstinadvertentisolation.~TemperaturealarmsprovideadequateleakdetectioncapabilityinthemainsteamtunneL~Theradiologicalconsequencesofa25gpmleakarewellmthinsafetylimits.

gaj,lli,fl>>g.4IItt RADIOLOGICALCONSEQUENCES25GPMSTEAMLEAKFOR2aHOURSDoseCategory2HRSiteBoundaryThyroid2HRSiteBoundaryWholeBody30DayLowPopulationZoneThyroid30DayLowPopulationZoneWholeBody25gpmCalculatedDose(rem)1.89x10~9.55x102.17Ã101,09x10FSARSteamLineBreakDose(rem)3.072.98x10'.98x106.77x10SRPAcceptanceCriteria3002530025 S"IA3'Jt OBSERVATIONS-DESIGNBASISDESIGNBASISFLOWRATE-ECCSandRWCVRooms-5gpm----25gpmRWCUPENETRATIONROOM.....RaisesetpointsHPCI,RCICRooms.........RaisesetpointsofCoolerInletHiAmbientTrip i(',I'I4"14"1q'C)p OBSERVATIONS-RHRROOMS1.STEAMLEAKSETPOINTBASIS2.ABSENCEOFSTEAMSUPPLY3.ISOLATIONOFSHUTDOWNCOOLINGSUCTION4.NOREUIREMENTFORSLDINCOLDSHUTDOWN5.MINIiKUOVERLAPIN.HOTSHUTDOWN6.PROPOSAL-ELIMiNATEISOLATIONFUNCTIONOFSLD-REPLACEWITHTEMPERATUREBASEDFUNCTIONFORSDCLEAkMGE OBSERVATIONS-RxBLDG1MAJNSTEAiVITU'NOEL1.FSAR-25GPMDESIGNBASIS2.ROOMCOOLERMODELINGDIFFICULTYFractionofsensiblevslatentheatremovalundersteamleakconditionsAutostartof2ndcoolerat13QF3.INITIALSTUDIES-LEAKAGEATRECTORTEMPERATURE4.FINALSTUDIES-.12,500LBS-M/HR5.APPLICATIONOFSETPOINTCALCULATIONMETHODOLOGY

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OBSERVATIONS-TURBBLDGiKAJNSTEAIVlTUNNEL1.ABSENCEOFCLOSEDGEOMETRY2.TEiVIPERATURKGRADIENTALONGTUNNEL-3.SENSITIVITYOFTEMPERATURETOLEAKLOCATION4.INADEQUACYOF25GPMASSETPOINTBASISS.PRESENTOPERATIONSUBJECTTOSPURIOUSISOLATIONDUETOSled%L1VhWGIN6.SYSTEMCOVERSONLYASjVGu'PORTIONOFMAINSTEAMPIPINGINTURBINEBUILDING.7.PROPOSAL-CO&iTERTISOLATIONFUNCTIONSTOFUNCTIONS ATTACHMENTB

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