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| {{#Wiki_filter:NRCForm366U.S.NUCLEARREGULATORYCOMMISSION(6-1998)LICENSEEEVENTREPORT(LER)(Seereverseforrequirednumberofdigits/charactersforeachblock)APPROVEDBYOMBNo.3150.0104EXPIRES06/30/2001ESTIMATEDBURDENPERRESPONSETOCOMPLYWITHTHISMANDATORYINFORMATIONCOLLECTIONREOVESD50.0HRS.REPORTEDLESSONSLEARNEDAREINCORPORATEDBJTOTHEUCEJISINGPROCESSANDFEDBACKTOINDUSTRY.FORWARDCOMMENTSREGARDUIGBURDENESTSJATETOTHEII&ORMATIONANORECORDSMANAGEMENTBRANCHIT4AS),V.S.NVCLEARRFGUIATORYCOMMISSION.WASHBJGTON.OC205S54XI.ANOTOTHEPAPERWORKREDUCTIONPROJECTtst50410l),OFFICEOFMANAGEMENTANDBUCGEf,WASIeNGTceLDC2050$FACILITYNAMEI1)CookNuclearPlantUnit1DOCKETNUMBERr2)05000-315PAGEI5)1of3TITLEI4)AuxiliaryBuildingESFVentilationSystemMayNotbeCapableofMaintainingESFRoomTemperaturesPost-AccidentMONTH04DAYYEAR201999EVENTDATE(5)YEAR1999LERNUMBER(8)SEQUENTIALNUMBER012REVISIONNUMBER00REPORTDATE(7)MONTHDAYYEAR05201999ILID.C.Cook,Unit2AILINAM05000-316DCNUMBEROTHERFACILITIESINVOLVED(8)OPERATINGMODE(9)POWERLEVEL(10)0%20.2201(b)20.2203(a)(1)20.2203(a)(2)(i)20.2203(a)(2)(v)20.2203(a)(3)(i)20.2203(a)(3)(ii)50.73(a)(2)(l)50.73(a)(2)(ii)50.73(a)(2)(iii)50.73(a)(2)(viii)50.73(a)(2)(x)73.71THISREPORTISSUBMITTEDPURSUANTTOTHEREQUIREMENTSOF10CFRII:(Checkoneormore)(11)20.2203(a)(2)(ii)20.2203(a)(2)(iii)20.2203(a)(2)(iv)20.2203(a)(4)50.36(c)(1)50.36(c)(2)LICENSEECONTACTFORTHISLER(12)50.73(a)(2)(iv)50.73(a)(2)(v)50.73(a)(2)(vii)OTHERSpecii/yInAbstractbekrrrornNRCForm366ANAMEMs.BrendaW.O'ourke,ComplianceEngineerTELEPHONENUMBER(IIK5udeAreaCode)(616)465-5901x2604COMPLETEONELINEFOREACHCOMPONENTFAILUREDESCRIBEDINTHISREPORT(13).CAUSESYSTEMCOMPONENTMANUFACTURERREPORTABLETOEPIXCAUSESYSTEMCOMPONENTMANUFACTURERREPORTABLETOEPIXSUPPLEMENTALREPORTEXPECTED(14XYES(IfYes,completeEXPECTEDSUBMISSIONDATE)NOEXPECTEDSUBMISSIONDATE15MONTH10DAY311999Abstract(Limitto1400spaces,I.e.,approximately15singie-spacedtypewrittenlines)(16)OnApril20,1999,duringperformanceoftheExpandedSystemReadinessReview(ESRR)fortheAuxiliaryBuildingVentilationSystems,itwasconcludedthatthereisinsufficientassurancethattheEngineeredSafetyFeaturesVentilation(AES)systemiscapableofperformingitssafetyandaccidentmitigationfunction.Thisconclusionwasbasedonapreliminaryevaluationofnumerousidentifiedsystemdeficienciestakenintheaggregate.Specifically,significanterrorsincalculationsforauxiliarybuildingEngineeredSafetyFeaturescubicletemperaturesexpectedduringpostulatedaccidentscenarios,vulnerabilityofAESdampercontrolairsystemmodificationtosinglefailure;andlackofmissileprotectionfortheComponentCoolingWaterpumpareasupplyfans.Basedonthecombinedeffectsofthesedeficiencies,theabilityoftheAESsystemtomaintainauxiliarybuildingtemperaturestowithinsafety-relatedequipmentdesigntemperaturesunderaccidentconditionscannotbeassured.Thepreliminarycausesforidentifiedconditionsare:inadequatecontrolofsystemdesigninputs;failuretoadequatelyimplementsinglefailuredesigncriteriaduringthemodificationprocess;andlackofacleardefinitionindesignandlicensingdocumentsregardingdesignrequirementsforsystemprotectionagainstmissileeffects.AcomprehensiveactionplanisbeingdevelopedtodeterminetheauxiliarybuildingdesigntemperaturesrequiredtobemaintainedbytheAESventilationsystem.Inaddition,asinglefailureanalysisfortheAESventilationsystemwillbeperformedtoidentifyfailuresthatcouldpreventthesystemfromperformingitsdesignandsafetyfunction.Basedontheresultsofthecompletedevaluation,informationregardingthesafetysignificance,andcorrectiveandpreventiveactionswillbeprovidedinanupdatetothisLER.9905260279990520PDRADOCK050003'l5SPDR | | {{#Wiki_filter:NRCForm366U.S.NUCLEARREGULATORY COMMISSION (6-1998)LICENSEEEVENTREPORT(LER)(Seereverseforrequirednumberofdigits/characters foreachblock)APPROVEDBYOMBNo.3150.0104 EXPIRES06/30/2001 ESTIMATED BURDENPERRESPONSETOCOMPLYWITHTHISMANDATORY INFORMATION COLLECTION REOVESD50.0HRS.REPORTEDLESSONSLEARNEDAREINCORPORATED BJTOTHEUCEJISING PROCESSANDFEDBACKTOINDUSTRY. |
| | FORWARDCOMMENTSREGARDUIG BURDENESTSJATETOTHEII&ORMATION ANORECORDSMANAGEMENT BRANCHIT4AS),V.S.NVCLEARRFGUIATORY COMMISSION. |
| | WASHBJGTON. |
| | OC205S54XI. |
| | ANOTOTHEPAPERWORK REDUCTION PROJECTtst50410l), |
| | OFFICEOFMANAGEMENT ANDBUCGEf,WASIeNGTceL DC2050$FACILITYNAMEI1)CookNuclearPlantUnit1DOCKETNUMBERr2)05000-315 PAGEI5)1of3TITLEI4)Auxiliary BuildingESFVentilation SystemMayNotbeCapableofMaintaining ESFRoomTemperatures Post-Accident MONTH04DAYYEAR201999EVENTDATE(5)YEAR1999LERNUMBER(8)SEQUENTIAL NUMBER012REVISIONNUMBER00REPORTDATE(7)MONTHDAYYEAR05201999ILID.C.Cook,Unit2AILINAM05000-316 DCNUMBEROTHERFACILITIES INVOLVED(8)OPERATING MODE(9)POWERLEVEL(10) 0%20.2201(b)20.2203(a)(1) 20.2203(a)(2)(i) 20.2203(a)(2)(v) 20.2203(a)(3)(i) 20.2203(a)(3)(ii) 50.73(a)(2)(l) 50.73(a)(2)(ii) 50.73(a)(2)(iii) 50.73(a)(2)(viii) 50.73(a)(2)(x) 73.71THISREPORTISSUBMITTED PURSUANTTOTHEREQUIREMENTS OF10CFRII:(Checkoneormore)(11)20.2203(a)(2)(ii) 20.2203(a)(2)(iii) 20.2203(a)(2)(iv) 20.2203(a)(4) 50.36(c)(1) 50.36(c)(2) |
| | LICENSEECONTACTFORTHISLER(12)50.73(a)(2)(iv) 50.73(a)(2)(v) 50.73(a)(2)(vii) |
| | OTHERSpecii/yInAbstractbekrrrornNRCForm366ANAMEMs.BrendaW.O'ourke,Compliance EngineerTELEPHONE NUMBER(IIK5udeAreaCode)(616)465-5901x2604COMPLETEONELINEFOREACHCOMPONENT FAILUREDESCRIBED INTHISREPORT(13).CAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TOEPIXCAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TOEPIXSUPPLEMENTAL REPORTEXPECTED(14XYES(IfYes,completeEXPECTEDSUBMISSION DATE)NOEXPECTEDSUBMISSION DATE15MONTH10DAY311999Abstract(Limitto1400spaces,I.e.,approximately 15singie-spaced typewritten lines)(16)OnApril20,1999,duringperformance oftheExpandedSystemReadiness Review(ESRR)fortheAuxiliary BuildingVentilation Systems,itwasconcluded thatthereisinsufficient assurance thattheEngineered SafetyFeaturesVentilation (AES)systemiscapableofperforming itssafetyandaccidentmitigation function. |
| | Thisconclusion wasbasedonapreliminary evaluation ofnumerousidentified systemdeficiencies takenintheaggregate. |
| | Specifically, significant errorsincalculations forauxiliary buildingEngineered SafetyFeaturescubicletemperatures expectedduringpostulated accidentscenarios, vulnerability ofAESdampercontrolairsystemmodification tosinglefailure;andlackofmissileprotection fortheComponent CoolingWaterpumpareasupplyfans.Basedonthecombinedeffectsofthesedeficiencies, theabilityoftheAESsystemtomaintainauxiliary buildingtemperatures towithinsafety-related equipment designtemperatures underaccidentconditions cannotbeassured.Thepreliminary causesforidentified conditions are:inadequate controlofsystemdesigninputs;failuretoadequately implement singlefailuredesigncriteriaduringthemodification process;andlackofacleardefinition indesignandlicensing documents regarding designrequirements forsystemprotection againstmissileeffects.Acomprehensive actionplanisbeingdeveloped todetermine theauxiliary buildingdesigntemperatures requiredtobemaintained bytheAESventilation system.Inaddition, asinglefailureanalysisfortheAESventilation systemwillbeperformed toidentifyfailuresthatcouldpreventthesystemfromperforming itsdesignandsafetyfunction. |
| | Basedontheresultsofthecompleted evaluation, information regarding thesafetysignificance, andcorrective andpreventive actionswillbeprovidedinanupdatetothisLER.9905260279 990520PDRADOCK050003'l5 SPDR |
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| NRCFORM366AU.S.NUCLEARREGULATORYCOMMISSION(6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATIONFACILITYNAME(1)CookNuclearPlantUnit1DOCKETNUMBER(2)05000-315YEARLERNUMBER(6)SEQUENTIALNUMBERREVISIONNUMBERPAGE(3)2of3TEXT(Ifmorespaceisrequired,useadditionalcopiesofNRCForm(366A)(17)ConditionsPriortoEventUnit1wasinMode5,ColdShutdownUnit2wasinMode5,ColdShutdown199901200DescritionofEventOnApril20,1999,duringperformanceoftheExpandedSystemReadinessReview(ESRR)fortheAuxiliaryBuildingVentilationSystems,itwasconcludedthatthereisinsufficientassurancethattheEngineeredSafetyFeaturesVentilation(AES)systemiscapableofperformingitssafetyandaccidentmitigationfunction.Thisconclusionwasbasedonapreliminaryevaluationofnumerousidentifiedsystemdeficienciestakenintheaggregate.Specifically,significanterrorsincalculationsforauxiliarybuildingEngineeredSafetyFeatures(ESF)cubicletemperaturesexpectedduringpostulatedaccidentscenarios,combinedwithsmalldesignmarginsthatexistedbetweencalculatedroomtemperaturesanddesignrequirements;vulnerabilityofAESdampercontrolairsystemmodificationtosinglefailure;andlackofmissileprotectionfortheComponentCoolingWater(CCW)pumpareasupplyfanswhichcouldresultinasinglecatastrophicfailure-generatedmissileimpactingbothtrainsofAES.Basedonthecombinedaffectsofthesedeficiencies,theabilityoftheUnit1and2AESsystemstomaintainauxiliarybuildingtemperaturestowithinsafety-relatedequipmentdesigntemperaturesunderallaccidentconditionscannotbeassured.Inaccordancewiththerequirementsof10CFR50.72(b)(2)(iii)(D),a4hournotificationwasmadetotheNRConApril20,1999,at1645hours,foranyeventorconditionthatalonecouldhavepreventedthefulfillmentofthesafetyfunctionofstructuresorsystemsthatareneededtomitigatetheconsequencesofanaccident.CauseofEventThepreliminarycausefortheuseofnon-conservativeandincorrectassumptionsinauxiliarybuildingheatloadcalculationsisduetoinadequatecontrolofsystemdesigninputs.ThisissuewaspreviouslyidentifiedinAEP:NRC:1260GH,datedMarch19,1999,"EnforcementActions98-150,98-151,98-152and98-186,ReplytoNoticeofViolationDatedOctober13,1998."ThepreliminarycauseforAESdamperdesignsinglefailurevulnerabilityisfailureofthedesignchangeprocesstoidentifythepotentialadverseimpactontheAESsystemcreatedbythemodificationtothedampercontrolairsystemin1997.ThepreliminarycauseforCCWpumpareasupplyfansusceptibilitytomissileeffectsislackofacleardefinitionindesignandlicensingdocumentsregardingAESdesignrequirementsforprotectionagainstmissileeffects.AnalsisofEventThisLERissubmittedinaccordancewith10CFR50.73(a)(2)(v)(D)foraconditionthatcouldpreventthefulfillmentofthesafetyfunctionsoftheAESsystemthatareneededtomitigatetheconsequencesofanaccident:TheAESsystemsafetyandaccidentmitigationfunctionistoprovidesufficientcoolingtotheauxiliarybuildinggeneralareasandESFequipmentroomsrequiredtooperateduringaccidentconditions.ThisincludestheCCW,ContainmentSpray,ResidualHeatRemoval,ChargingandSafetyInjectionequipmentrooms.TheAESsystemalsomaintainstheauxiliarybuildingatanegativepressurerelativetotheoutsideenvironmenttoensureradioactivecontaminationreleasedduringanaccidentiscontainedwithintheauxiliarybuilding,filteredandexhaustedtotheenvironmentviaamonitored,releasepath.Inaddition,TechnicalSpecification3.7.6.1requiresthattwoindependentAESventilationsystemfan/filterexhausttrainsbeoperableinModes1through4.Calculationsweredevelopedtoestablishtheauxiliarybuildingheatloads,ESFcubicleroomandgeneralareatemperaturesduringnormal,shutdownandaccidentconditions.DuringtheESRRreviewofthesecalculations,numerousdiscrepancieswereidentified.Forexample,calculationofauxiliarybuildingareatemperatureduringaccidentconditionsNRCFORM366A(6-1996) | | NRCFORM366AU.S.NUCLEARREGULATORY COMMISSION (6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION FACILITYNAME(1)CookNuclearPlantUnit1DOCKETNUMBER(2) 05000-315 YEARLERNUMBER(6)SEQUENTIAL NUMBERREVISIONNUMBERPAGE(3)2of3TEXT(Ifmorespaceisrequired, useadditional copiesofNRCForm(366A)(17)Conditions PriortoEventUnit1wasinMode5,ColdShutdownUnit2wasinMode5,ColdShutdown199901200DescritionofEventOnApril20,1999,duringperformance oftheExpandedSystemReadiness Review(ESRR)fortheAuxiliary BuildingVentilation Systems,itwasconcluded thatthereisinsufficient assurance thattheEngineered SafetyFeaturesVentilation (AES)systemiscapableofperforming itssafetyandaccidentmitigation function. |
| NRCFORM366AU.S.NUCLEARREGULATORYCOMMISSION(6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATIONFACILITYNAME(1)CookNuclearPlantUnit1DOCKETNUMBER(2)05000-315YEARLERNUMBER(6)SEQUENTIALNUMBERREVISIONNUMBERPAGE(3)3of3199901200TEXT(ifmorespaceisrequired,useadditionalcopiesofNRCForm(366A)(17)didnotincludetheheatloadfortheCCWsystempiping.Thisequipmentisconsideredasignificantheatloadintheauxiliarybuildingandexcludingitfromthecalculationcouldresultinnon-conservativeauxiliarybuildingareatemperaturevalues.Inaddition,thesevaluesserveasinputassumptionstootherauxiliarybuildingventilationcalculations.Asaresult,actualauxiliarybuildingareaandESFcubicleroomtemperaturescouldimpactthequalificationoftheESFequipmentlocatedintheareasservedbytheAESandCCWpumpareaventilationsystems.TheAESventilationsystemconsistsoftwofan/filterexhausttrains(oneinstandby)whichdrawsairfromtheauxiliarybuildingthroughtheequipmentcubiclesfromacommonventduct,anddischargestheexhausttotheoutsideatmosphereviatheventstack.Eachtrainconsistsofaroughingfilter,highefficiencyparticulateair(HEPA)filters,andanormallyclosedpneumaticallyoperatedfacedamper.Inaddition,eachtraincontainsabypassductwithanormallyopenpneumaticallyoperatedbypassdamperwhichdirectsairflowaroundthecharcoaladsorbers.Duringnormaloperation,onefan/filterunitoperatescontinuously,directingtheexhaustairthroughtheroughingandHEPAfilters,bypassingthecharcoalfilters,anddischargingtotheunitvent.Thisoperationaidsinairdistributionwithintheauxiliarybuilding,isolatestheatmosphereinthecubiciesbyinducingadraftthroughtheenteringportalsandremovesanyheatgeneratedwithintheenclosures.In1997,amodificationtothedampercontrolairsystemincludedtheinstallationofsolenoidvalvesintheairlinestothefaceandbypassdampers.Duringtheperformanceofsurveillancetest12OHP4030STP.25A/8,ontwoseparateoccasions,thefacedampersolenoidvalvefailed,resultinginthefacedamperfailingtoopenwhilethebypassdampersremainedclosed.Fornon-Slinitiatedevents,afailureofthefacedampersolenoidtoopenthe'facedamperorthebypassdampersolenoidtoopenthebypassdamperinresponsetoacontrolsignalcouldresultinboththefaceandbypass.dampersbeingintheclosedposition,blockingallairflowthroughtheaffectedtrain.IntheeventofaPhaseBIsolationsignal,thestandbytrainisenergizedandthebypassdampersautomaticallycloseandthefacedampersopentoexhaustairdirectlythroughthecharcoalfilters,roughingandHEPAfilters.AlthoughthesinglefailureofeitherthebypassorfacedampersolenoidvalvewouldrenderonetrainofAESinoperable,itwouldnotimpactthecapabilityofthestandbyfan/filtertrainfromperformingitssafetyandaccidentmitigationfunction.TheAESsystemdesignincludesthreevaneaxialsupplyfanslocatedintheCCWequipmentroomwhicharelocatedsidebyside,andconnectedtoacommonintakeplenumanddischargeduct.Becausevaneaxialfansaresusceptibletofanbladefailures,thefanbladesareapotentialmissilesourcewhichcouldimpactthefunctionofadjacentsafetyrelatedcomponents.Asaresult,failureoftheCCWpumpareasupplyfanscouldimpacttheabilityoftheAESsystemtomaintainESFcubicletemperaturestowithinequipmentdesigntemperatures,impactingthequalificationoftheESFequipment.BecauseofthenumeroussystemdeficienciesidentifiedduringtheESRR,acomprehensiveactionplanisbeingdevelopedtoevaluatetheidentifiedconditions.UntiltheaggregateeffectoftheseconditionsonAESsystemperformanceisevaluated,theoverallsafetyimpactcannotbedetermined.CorrectiveActionsAcomprehensiveactionplanisbeingdevelopedtodeterminetheauxiliarybuildingdesigntemperaturesrequiredtobemaintainedbytheauxiliarybuildingventilationsystems:Inaddition,asinglefailureanalysisfortheAESventilationsystemwillbeperformedtoidentifyfailureswhichcouldpreventthesystemfromperformingitsdesignandsafetyfunction.Basedontheresultsofthecompletedevaluation,additionalinformationregardingsafetysignificance,includingcorrectiveandpreventiveactionswillbeprovidedinanupdatetothisLER.PreviousSimilarEventsLER315/97-023-00NRCFORM366A(6-1998)}} | | Thisconclusion wasbasedonapreliminary evaluation ofnumerousidentified systemdeficiencies takenintheaggregate. |
| | Specifically, significant errorsincalculations forauxiliary buildingEngineered SafetyFeatures(ESF)cubicletemperatures expectedduringpostulated accidentscenarios, combinedwithsmalldesignmarginsthatexistedbetweencalculated roomtemperatures anddesignrequirements; vulnerability ofAESdampercontrolairsystemmodification tosinglefailure;andlackofmissileprotection fortheComponent CoolingWater(CCW)pumpareasupplyfanswhichcouldresultinasinglecatastrophic failure-generated missileimpacting bothtrainsofAES.Basedonthecombinedaffectsofthesedeficiencies, theabilityoftheUnit1and2AESsystemstomaintainauxiliary buildingtemperatures towithinsafety-related equipment designtemperatures underallaccidentconditions cannotbeassured.Inaccordance withtherequirements of10CFR50.72(b)(2)(iii)(D), |
| | a4hournotification wasmadetotheNRConApril20,1999,at1645hours,foranyeventorcondition thatalonecouldhaveprevented thefulfillment ofthesafetyfunctionofstructures orsystemsthatareneededtomitigatetheconsequences ofanaccident. |
| | CauseofEventThepreliminary causefortheuseofnon-conservative andincorrect assumptions inauxiliary buildingheatloadcalculations isduetoinadequate controlofsystemdesigninputs.Thisissuewaspreviously identified inAEP:NRC:1260GH, datedMarch19,1999,"Enforcement Actions98-150,98-151,98-152and98-186,ReplytoNoticeofViolation DatedOctober13,1998."Thepreliminary causeforAESdamperdesignsinglefailurevulnerability isfailureofthedesignchangeprocesstoidentifythepotential adverseimpactontheAESsystemcreatedbythemodification tothedampercontrolairsystemin1997.Thepreliminary causeforCCWpumpareasupplyfansusceptibility tomissileeffectsislackofacleardefinition indesignandlicensing documents regarding AESdesignrequirements forprotection againstmissileeffects.AnalsisofEventThisLERissubmitted inaccordance with10CFR50.73(a)(2)(v)(D) foracondition thatcouldpreventthefulfillment ofthesafetyfunctions oftheAESsystemthatareneededtomitigatetheconsequences ofanaccident: |
| | TheAESsystemsafetyandaccidentmitigation functionistoprovidesufficient coolingtotheauxiliary buildinggeneralareasandESFequipment roomsrequiredtooperateduringaccidentconditions. |
| | ThisincludestheCCW,Containment Spray,ResidualHeatRemoval,ChargingandSafetyInjection equipment rooms.TheAESsystemalsomaintains theauxiliary buildingatanegativepressurerelativetotheoutsideenvironment toensureradioactive contamination releasedduringanaccidentiscontained withintheauxiliary |
| | : building, filteredandexhausted totheenvironment viaamonitored, releasepath.Inaddition, Technical Specification 3.7.6.1requiresthattwoindependent AESventilation systemfan/filter exhausttrainsbeoperableinModes1through4.Calculations weredeveloped toestablish theauxiliary buildingheatloads,ESFcubicleroomandgeneralareatemperatures duringnormal,shutdownandaccidentconditions. |
| | DuringtheESRRreviewofthesecalculations, numerousdiscrepancies wereidentified. |
| | Forexample,calculation ofauxiliary buildingareatemperature duringaccidentconditions NRCFORM366A(6-1996) |
| | NRCFORM366AU.S.NUCLEARREGULATORY COMMISSION (6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION FACILITYNAME(1)CookNuclearPlantUnit1DOCKETNUMBER(2) 05000-315 YEARLERNUMBER(6)SEQUENTIAL NUMBERREVISIONNUMBERPAGE(3)3of3199901200TEXT(ifmorespaceisrequired, useadditional copiesofNRCForm(366A)(17)didnotincludetheheatloadfortheCCWsystempiping.Thisequipment isconsidered asignificant heatloadintheauxiliary buildingandexcluding itfromthecalculation couldresultinnon-conservative auxiliary buildingareatemperature values.Inaddition, thesevaluesserveasinputassumptions tootherauxiliary buildingventilation calculations. |
| | Asaresult,actualauxiliary buildingareaandESFcubicleroomtemperatures couldimpactthequalification oftheESFequipment locatedintheareasservedbytheAESandCCWpumpareaventilation systems.TheAESventilation systemconsistsoftwofan/filter exhausttrains(oneinstandby)whichdrawsairfromtheauxiliary buildingthroughtheequipment cubiclesfromacommonventduct,anddischarges theexhausttotheoutsideatmosphere viatheventstack.Eachtrainconsistsofaroughingfilter,highefficiency particulate air(HEPA)filters,andanormallyclosedpneumatically operatedfacedamper.Inaddition, eachtraincontainsabypassductwithanormallyopenpneumatically operatedbypassdamperwhichdirectsairflowaroundthecharcoaladsorbers. |
| | Duringnormaloperation, onefan/filter unitoperatescontinuously, directing theexhaustairthroughtheroughingandHEPAfilters,bypassing thecharcoalfilters,anddischarging totheunitvent.Thisoperation aidsinairdistribution withintheauxiliary |
| | : building, isolatestheatmosphere inthecubiciesbyinducingadraftthroughtheenteringportalsandremovesanyheatgenerated withintheenclosures. |
| | In1997,amodification tothedampercontrolairsystemincludedtheinstallation ofsolenoidvalvesintheairlinestothefaceandbypassdampers.Duringtheperformance ofsurveillance test12OHP4030STP.25A/8, ontwoseparateoccasions, thefacedampersolenoidvalvefailed,resulting inthefacedamperfailingtoopenwhilethebypassdampersremainedclosed.Fornon-Slinitiated events,afailureofthefacedampersolenoidtoopenthe'facedamperorthebypassdampersolenoidtoopenthebypassdamperinresponsetoacontrolsignalcouldresultinboththefaceandbypass.dampersbeingintheclosedposition, blockingallairflowthroughtheaffectedtrain.IntheeventofaPhaseBIsolation signal,thestandbytrainisenergized andthebypassdampersautomatically closeandthefacedampersopentoexhaustairdirectlythroughthecharcoalfilters,roughingandHEPAfilters.AlthoughthesinglefailureofeitherthebypassorfacedampersolenoidvalvewouldrenderonetrainofAESinoperable, itwouldnotimpactthecapability ofthestandbyfan/filter trainfromperforming itssafetyandaccidentmitigation function. |
| | TheAESsystemdesignincludesthreevaneaxial supplyfanslocatedintheCCWequipment roomwhicharelocatedsidebyside,andconnected toacommonintakeplenumanddischarge duct.Becausevaneaxial fansaresusceptible tofanbladefailures, thefanbladesareapotential missilesourcewhichcouldimpactthefunctionofadjacentsafetyrelatedcomponents. |
| | Asaresult,failureoftheCCWpumpareasupplyfanscouldimpacttheabilityoftheAESsystemtomaintainESFcubicletemperatures towithinequipment designtemperatures, impacting thequalification oftheESFequipment. |
| | Becauseofthenumeroussystemdeficiencies identified duringtheESRR,acomprehensive actionplanisbeingdeveloped toevaluatetheidentified conditions. |
| | Untiltheaggregate effectoftheseconditions onAESsystemperformance isevaluated, theoverallsafetyimpactcannotbedetermined. |
| | Corrective ActionsAcomprehensive actionplanisbeingdeveloped todetermine theauxiliary buildingdesigntemperatures requiredtobemaintained bytheauxiliary buildingventilation systems:Inaddition, asinglefailureanalysisfortheAESventilation systemwillbeperformed toidentifyfailureswhichcouldpreventthesystemfromperforming itsdesignandsafetyfunction. |
| | Basedontheresultsofthecompleted evaluation, additional information regarding safetysignificance, including corrective andpreventive actionswillbeprovidedinanupdatetothisLER.PreviousSimilarEventsLER315/97-023-00 NRCFORM366A(6-1998)}} |
LER 99-012-00:on 990420,concluded That Auxiliary Bldg ESF Ventilation Sys Not Capable of Maintaining ESF Room Temps post-accident.Caused by Inadequate Control of Sys Design Inputs.Comprehensive Action Plan Being Developed| ML17325B600 |
| Person / Time |
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| Site: |
Cook  |
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| Issue date: |
05/20/1999 |
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| From: |
OROURKE B W
INDIANA MICHIGAN POWER CO. |
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| To: |
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| Shared Package |
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| ML17325B598 |
List: |
|---|
| References |
|---|
| LER-99-012, LER-99-12, NUDOCS 9905260279 |
| Download: ML17325B600 (4) |
|
Similar Documents at Cook |
|---|
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LER 99-016-00:on 990615,TS Requirements for Source Range Neutron Flux Monitors Not Met.Caused by Failure to Understand Design Basis of Plant.Procedures Revised.With 990713 Ltr
ML17326A0331999-07-0101 July 1999
LER 99-004-01:on 971030,failure to Perform TS Surveillance Analyses of Reactor Coolant Chemistry with Fuel Removed Was Noted.Caused by Ineffective Mgt of Tss.Chemistry Personnel Have Been Instructed on Requirement to Follow TS as Written
ML17326A0151999-06-18018 June 1999
LER 99-014-00:on 990521,determined That Boron Injection Tank Manway Bolts Were Not Included in ISI Program,Creating Missed Exam for Previous ISI Interval.Caused by Programmatic Weakness.Isi Program & Associated ISI Database Modified
ML17325B6311999-06-0101 June 1999
LER 99-S03-00:on 990430,vital Area Barrier Degradation Was Noted.Caused by Inadequate Insp & Maint of Vital Area Barrier.Repairs & Mods Were Made to Barriers to Eliminate Degraded & Nonconforming Conditions
ML17325B6421999-06-0101 June 1999
LER 99-013-00:on 990327,safety Injection & Centrifugal Charging Throttle Valve Cavitation During LOCA Could Have Led to ECCS Pump Failure.Caused by Inadequate Original Design Application of Si.Throttle Valves Will Be Developed
ML17325B6351999-05-28028 May 1999
LER 99-S02-00:on 990428,vulnerability in Safeguard Sys That Could Allow Unauthorized Access to Protected Area Was Noted. Caused by Inadequate Original Plant Design.Mods Were Made to Wall Opening to Eliminate Nonconforming Conditions
ML17265A8231999-05-24024 May 1999
LER 98-037-01:on 990422,determined That Ice Condenser Bypass Leakage Exceeds Design Basis Limit.Caused by Pressure Seal Required by Revised W Design Not Incorporated Into Aep Design.Numerous Matl Condition Walkdowns & Assessments Made
ML17325B6001999-05-20020 May 1999
LER 99-012-00:on 990420,concluded That Auxiliary Bldg ESF Ventilation Sys Not Capable of Maintaining ESF Room Temps post-accident.Caused by Inadequate Control of Sys Design Inputs.Comprehensive Action Plan Being Developed
ML17325B5861999-05-10010 May 1999
LER 99-002-00:on 990415,discovered That TS 4.0.5 Requirements Were Not Met Due to Improperly Performed Test. Caused by Incorrect Interpretation of ASME Code.App J Testing Will Be Completed & Procedures Will Be Revised
ML17325B5811999-05-0404 May 1999
LER 99-011-00:on 990407,air Sys for EDG Will Not Support Long Operability.Caused by Original Design Error.Temporary Mod to Supply Makeup Air Capability in Modes 5 & 6 Was Prepared
ML17325B5771999-05-0303 May 1999
LER 99-010-00:on 990401,RCS Leak Detection Sys Sensitivity Not in Accordance with Design Requirements Occurred.Caused by Inadequate Original Design of Containment Sump Level. Evaluation Will Be Performed to Clearly Define Design
ML17325B5581999-04-16016 April 1999
LER 99-006-00:on 990115,personnel Identified Discrepancy Between TS 3.9.7 Impact Energy Limit & Procedure 12 Ohp 4030.STP.046.Caused by Lack of Design Basis Control.Placed Procedure 12 Ohp 4030.STP.046 on Administrative Hold
ML17325B5471999-04-12012 April 1999
LER 99-009-00:on 990304,as-found RHR Safety Relief Valve Lift Setpoint Greater than TS Limit Occurred.Cause Investigation for Condition Has Not Been Completed.Update to LER Will Be Submitted,Upon Completion of Investigation
ML17325B5321999-04-0707 April 1999
LER 99-S01-00:on 990308,discovered That Lock for Vital Gate Leading to Plant 4KV Switchgear Area Was Nonconforming & Vulnerable to Unauthorized Access.Caused by Inadequate Gate Design & Inadequate Procedures.Mods Are Being Made to Gate
ML17325B5161999-04-0101 April 1999
LER 99-007-00:on 981020,calculations Showed That Divider Barrier Between Upper & Lower Containment Vols Were Overstressed.Engineers Are Currently Working on Analyses of Loads & Stress on Enclosures
ML17325B5221999-03-29029 March 1999
LER 99-001-00:on 960610,degraded Component Cooling Water Flow to Containment Main Steam Line Penetrations,Identified on 990226.Caused by Inadequate Understanding of Design Basis.Additional Investigations Ongoing
ML17325B4801999-03-18018 March 1999
LER 99-004-00:on 971030,failure to Perform TS Surveillance Analyses of Rc Chemistry with Fuel Removed Was Noted.Cause of Event Is Under Investigation.Corrected Written Job Order Activities Used to Control SD Chemistry Sampling
ML17325B4741999-03-18018 March 1999
LER 99-005-00:on 940512,determined That Rt Breaker Manual Actuations During Rod Drop Testing Were Not Previously Reported.Caused by Lack of Training.Addl Corrective Actions,Including Preventative Actions May Be Developed
ML17325B4571999-02-24024 February 1999
LER 99-003-00:on 990107,CR Pressurization Sys Surveillance Test Did Not Test Sys in Normal Operating Condition.Caused by Failure to Recognize Door 12DR-AUX415 as Part of CR Pressure Boundary.Performed Walkdown of Other Doors
ML17335A5171999-02-11011 February 1999
LER 99-002-00:on 990112,determined That RCS Pressurizer PORVs Had Not Been Tested,Per Ts.Caused by Inadequate Scheduling Controls Allowing Personnel Error.Surveillance Procedure Was Completed & Updated LER Will Be Submitted
ML17335A5141999-02-10010 February 1999
LER 99-001-00:on 990106,noted That GE Hfa Relays Installed in EDGs May Not Meet Seismic Qualification.Caused by Operating Experience Info Incorrectly Dispositioned in 1985. Updated LER Will Be Submitted by 990405
ML17335A5011999-02-0101 February 1999
LER 98-060-00:on 981231,identified That Rt Sys Response Time Testing Did Not Comply with TS Definition.Caused by Inadequate Procedures.Corrective Actions Will Be Developed & Update to LER Will Be Submitted by 990415.With 990201 Ltr
ML17335A4951999-01-29029 January 1999
LER 98-059-00:on 981230,interim LER -single Failure in Containment Spray Sys Could Result in Containment Spray Ph Outside Design Occurred.Investigation Into Condition Continuing.Update Will Be Submitted by 990514 Ltr
ML17335A4961999-01-27027 January 1999
LER 98-057-00:on 981228,discovered That AFW Valves Were Not Tested IAW Inservice Testing Program.Caused by Failure to Recognize Design Bases Features Re Afws by Personnel. Updated LER Will Be Submittted by 990415.With 990127 Ltr
ML17335A4921999-01-19019 January 1999
LER 98-052-01:on 981128,no Analysis for NSR Sc Manual Loader for Tdafwp Could Be Found in Original Design.Cause Due to All Failure Modes Not Considered When Compressed Air Sys Originally Designed.Performed Review of Components
ML17335A4721999-01-0606 January 1999
LER 98-055-00:on 981207,potential for Condition Outside of Design Bases for Rod Control Sys Was Noted.Caused by Calibration Error Coupled with Single Rod Failure.Condition Rept Investigation Is Ongoing
ML17335A4691999-01-0606 January 1999
LER 98-056-00:on 981211,hot Leg Nozzle Gaps Resulted in Plant Being in Unanalyzed Condition.Analyses Are Being Performed by W to Resolve Problem.Updated LER Will Be Submitted by 990211.With 990106 Ltr
ML17335A4661999-01-0505 January 1999
LER 98-049-00:on 981020,emergency Boron Injection Flow Path Was Inoperable.Caused by Original Design Deficiency. Engineering Evaluation of Event Is Continuing
ML17335A4631999-01-0404 January 1999
LER 98-054-00:on 981202,discovered That at Least One MSSV Had Not Been Reset as Required by Ts.Engineering Is Continuing Review of Extent of Condition for Event.Updated LER Will Be Submitted by 990129.With 990104 Ltr
ML17335A4481998-12-30030 December 1998
LER 98-053-00:on 981130,discovered Use of Inoperable Substitute Subcooling Margin Monitor.Caused by Condition Existing Since Installation of Plant Process Computer in 1992.Updated LER Will Be Submitted.With 981230 Ltr
ML17335A4581998-12-28028 December 1998
LER 98-052-00:on 981128,turbine Driven AFW Pump Speed Controller Failure Mode Occurred.Caused Because Not All Failure Modes Were Considered When Compressed Air Sys Was Originally Designed.Verified Current Design Change Process
ML17335A4281998-12-22022 December 1998
LER 98-051-00:on 981122,reactor Trip Signal from Manual Safety Injection Not Verified as Required by TS Surveillance,Was Discovered.Maintenance Currently Evaluating Significance & Cause of Event
ML17335A4111998-12-17017 December 1998
LER 98-047-00:on 981117,potential for Increase Leakage from Reactor Coolant Pump Seals Was Identified.Util Is Working with W to Resolve Issue.Current Expectations Are to Submit Update to LER by 990215.With 981217 Ltr
ML17335A4141998-12-16016 December 1998
LER 98-058-00:on 981216,postulated High Line Break Could Result in Condition Outside Design Bases for AF Occurred. Caused by Deficiencies Associated with Administration of HELB Program.Analysis of AF Will Be Completed by 990122
ML17335A4181998-12-16016 December 1998
LER 98-050-00:on 980814,ancillary Equipment Installed in Ice Condenser Was Not Designed to Withstand Design Basis Accident/Earthquake Loads.Caused by Lack of Established Design Criteria.Developed Design Criteria
ML17335A3871998-12-11011 December 1998
LER 98-031-01:on 980610,potential Common Mode Failure of RHR Pumps Were Noted.Caused by Inaccurate Values.Accurate Miniflow Numbers Have Been Determined by Flow Testing
ML17335A3821998-12-0808 December 1998
LER 98-039-01 Re EOP Step Conflicts with Small Break LOCA Analysis.Ler 98-039-00 Has Been Canceled.With 981208 Ltr
ML17335A3781998-12-0707 December 1998
LER 98-007-00:on 981106,high Energy Line Break Effects in Auxiliary FW Sys Was Noted.Cause of Event Is Under Investigation & Will Be Completed by 990220.Updated LER Will Be Submitted by 990310.With 981207 Ltr
ML17335A3771998-12-0303 December 1998
LER 98-046-00:on 981103,determined That Afs Was Unable to Meet Design Flow Requirements During Special Test.Caused by Failure to Consider All Aspects of Sys Operation in Design of Suction Basket Strainers.Sys Will Be Redesigned
ML17335A3741998-12-0202 December 1998
LER 97-011-02:on 970822,operation Was Noted Outside Design Bases for ECCS & CSP for Switchover to Recirculation Sump Suction.Caused by Ineffective Change Mgt.Revised Procedure for Switchover 01(02) Ohp 4023.ES-1.3
1999-09-17
[Table view]
Category:RO)
MONTHYEARML17335A5641999-10-18018 October 1999
LER 99-024-00:on 990708,literal TS Requirements Were Not Met by Accumlator Valve Surveillance.Caused by Misjudgement Made in Conversion from Initial DC Cook TS to W Std Ts.Submitted License Amend Request.With 991018 Ltr
ML17335A5531999-10-0707 October 1999
LER 99-023-00:on 990907,inadequate TS Surveillance Testing of ESW Pump ESF Response Time Noted.Caused by Inadequate Understanding of Plant Design Basis.Surveillance Tests Will Be Revised & Implemented
ML17326A1291999-09-17017 September 1999
LER 99-022-00:on 990609,electrical Bus Degraded Voltage Setpoints Too Low for Safety Related Loads,Was Discovered. Caused by Lack of Understanding of Design of Plant.No Immediate Corrective Actions Necessary
ML17326A1121999-08-27027 August 1999
LER 99-021-00:on 990728,determined That GL 96-01 Test Requirements Were Not Met in Surveillance Tests.Caused by Failure to Understand Full Extent of GL Requirements. Surveillance Procedures Will Be Revised or Developed
ML17326A1011999-08-26026 August 1999
LER 99-020-00:on 990727,EDGs Were Declared Inoperable.Caused by Inadequate Protection of Air Intake,Exhaust & Room Ventilation Structures from Tornado Missile Hazards. Implemented Compensatory Measures in Form of ACs
ML17326A0911999-08-16016 August 1999
LER 99-019-00:on 990716,noted Victoreen Containment Hrrms Not Environmentally Qualified to Withstand post-LOCA Conditions.Caused by Inadequate Design Control.Reviewing Options to Support Hrrms Operability in Modes 1-4
ML17326A0771999-08-0404 August 1999
LER 98-029-01:on 980422,noted That Fuel Handling Area Ventilation Sys Was Inoperable.Caused by Original Design Deficiency.Radiological Analysis for Spent Fuel Handling Accidents in Auxiliary Bldg Will Be Redone by 990830
ML17326A0741999-07-29029 July 1999
LER 99-018-00:on 990629,determined That Valve Yokes May Yield Under Combined Stress of Seismic Event & Static,Valve Closed,Stem Thrust.Caused by Inadequate Design of Associated Movs.Operability Determinations Were Performed for Valves
ML17326A0661999-07-26026 July 1999
LER 99-017-00:on 990625,noted That Improperly Installed Fuel Oil Return Relief Valve Rendered EDG Inoperable.Caused by Personnel Error.Fuel Oil Return Valve Was Replaced with Valve in Correct Orientation.With 990722 Ltr
ML17326A0651999-07-22022 July 1999
LER 98-014-03:on 980310,noted That Response to high-high Containment Pressure Procedure Was Not Consistent with Analysis of Record.Caused by Inadequate Interface with W. FRZ-1 Will Be Revised to Be Consistent with New Analysis
ML17326A0491999-07-13013 July 1999
LER 99-016-00:on 990615,TS Requirements for Source Range Neutron Flux Monitors Not Met.Caused by Failure to Understand Design Basis of Plant.Procedures Revised.With 990713 Ltr
ML17326A0331999-07-0101 July 1999
LER 99-004-01:on 971030,failure to Perform TS Surveillance Analyses of Reactor Coolant Chemistry with Fuel Removed Was Noted.Caused by Ineffective Mgt of Tss.Chemistry Personnel Have Been Instructed on Requirement to Follow TS as Written
ML17326A0151999-06-18018 June 1999
LER 99-014-00:on 990521,determined That Boron Injection Tank Manway Bolts Were Not Included in ISI Program,Creating Missed Exam for Previous ISI Interval.Caused by Programmatic Weakness.Isi Program & Associated ISI Database Modified
ML17325B6311999-06-0101 June 1999
LER 99-S03-00:on 990430,vital Area Barrier Degradation Was Noted.Caused by Inadequate Insp & Maint of Vital Area Barrier.Repairs & Mods Were Made to Barriers to Eliminate Degraded & Nonconforming Conditions
ML17325B6421999-06-0101 June 1999
LER 99-013-00:on 990327,safety Injection & Centrifugal Charging Throttle Valve Cavitation During LOCA Could Have Led to ECCS Pump Failure.Caused by Inadequate Original Design Application of Si.Throttle Valves Will Be Developed
ML17325B6351999-05-28028 May 1999
LER 99-S02-00:on 990428,vulnerability in Safeguard Sys That Could Allow Unauthorized Access to Protected Area Was Noted. Caused by Inadequate Original Plant Design.Mods Were Made to Wall Opening to Eliminate Nonconforming Conditions
ML17265A8231999-05-24024 May 1999
LER 98-037-01:on 990422,determined That Ice Condenser Bypass Leakage Exceeds Design Basis Limit.Caused by Pressure Seal Required by Revised W Design Not Incorporated Into Aep Design.Numerous Matl Condition Walkdowns & Assessments Made
ML17325B6001999-05-20020 May 1999
LER 99-012-00:on 990420,concluded That Auxiliary Bldg ESF Ventilation Sys Not Capable of Maintaining ESF Room Temps post-accident.Caused by Inadequate Control of Sys Design Inputs.Comprehensive Action Plan Being Developed
ML17325B5861999-05-10010 May 1999
LER 99-002-00:on 990415,discovered That TS 4.0.5 Requirements Were Not Met Due to Improperly Performed Test. Caused by Incorrect Interpretation of ASME Code.App J Testing Will Be Completed & Procedures Will Be Revised
ML17325B5811999-05-0404 May 1999
LER 99-011-00:on 990407,air Sys for EDG Will Not Support Long Operability.Caused by Original Design Error.Temporary Mod to Supply Makeup Air Capability in Modes 5 & 6 Was Prepared
ML17325B5771999-05-0303 May 1999
LER 99-010-00:on 990401,RCS Leak Detection Sys Sensitivity Not in Accordance with Design Requirements Occurred.Caused by Inadequate Original Design of Containment Sump Level. Evaluation Will Be Performed to Clearly Define Design
ML17325B5581999-04-16016 April 1999
LER 99-006-00:on 990115,personnel Identified Discrepancy Between TS 3.9.7 Impact Energy Limit & Procedure 12 Ohp 4030.STP.046.Caused by Lack of Design Basis Control.Placed Procedure 12 Ohp 4030.STP.046 on Administrative Hold
ML17325B5471999-04-12012 April 1999
LER 99-009-00:on 990304,as-found RHR Safety Relief Valve Lift Setpoint Greater than TS Limit Occurred.Cause Investigation for Condition Has Not Been Completed.Update to LER Will Be Submitted,Upon Completion of Investigation
ML17325B5321999-04-0707 April 1999
LER 99-S01-00:on 990308,discovered That Lock for Vital Gate Leading to Plant 4KV Switchgear Area Was Nonconforming & Vulnerable to Unauthorized Access.Caused by Inadequate Gate Design & Inadequate Procedures.Mods Are Being Made to Gate
ML17325B5161999-04-0101 April 1999
LER 99-007-00:on 981020,calculations Showed That Divider Barrier Between Upper & Lower Containment Vols Were Overstressed.Engineers Are Currently Working on Analyses of Loads & Stress on Enclosures
ML17325B5221999-03-29029 March 1999
LER 99-001-00:on 960610,degraded Component Cooling Water Flow to Containment Main Steam Line Penetrations,Identified on 990226.Caused by Inadequate Understanding of Design Basis.Additional Investigations Ongoing
ML17325B4801999-03-18018 March 1999
LER 99-004-00:on 971030,failure to Perform TS Surveillance Analyses of Rc Chemistry with Fuel Removed Was Noted.Cause of Event Is Under Investigation.Corrected Written Job Order Activities Used to Control SD Chemistry Sampling
ML17325B4741999-03-18018 March 1999
LER 99-005-00:on 940512,determined That Rt Breaker Manual Actuations During Rod Drop Testing Were Not Previously Reported.Caused by Lack of Training.Addl Corrective Actions,Including Preventative Actions May Be Developed
ML17325B4571999-02-24024 February 1999
LER 99-003-00:on 990107,CR Pressurization Sys Surveillance Test Did Not Test Sys in Normal Operating Condition.Caused by Failure to Recognize Door 12DR-AUX415 as Part of CR Pressure Boundary.Performed Walkdown of Other Doors
ML17335A5171999-02-11011 February 1999
LER 99-002-00:on 990112,determined That RCS Pressurizer PORVs Had Not Been Tested,Per Ts.Caused by Inadequate Scheduling Controls Allowing Personnel Error.Surveillance Procedure Was Completed & Updated LER Will Be Submitted
ML17335A5141999-02-10010 February 1999
LER 99-001-00:on 990106,noted That GE Hfa Relays Installed in EDGs May Not Meet Seismic Qualification.Caused by Operating Experience Info Incorrectly Dispositioned in 1985. Updated LER Will Be Submitted by 990405
ML17335A5011999-02-0101 February 1999
LER 98-060-00:on 981231,identified That Rt Sys Response Time Testing Did Not Comply with TS Definition.Caused by Inadequate Procedures.Corrective Actions Will Be Developed & Update to LER Will Be Submitted by 990415.With 990201 Ltr
ML17335A4951999-01-29029 January 1999
LER 98-059-00:on 981230,interim LER -single Failure in Containment Spray Sys Could Result in Containment Spray Ph Outside Design Occurred.Investigation Into Condition Continuing.Update Will Be Submitted by 990514 Ltr
ML17335A4961999-01-27027 January 1999
LER 98-057-00:on 981228,discovered That AFW Valves Were Not Tested IAW Inservice Testing Program.Caused by Failure to Recognize Design Bases Features Re Afws by Personnel. Updated LER Will Be Submittted by 990415.With 990127 Ltr
ML17335A4921999-01-19019 January 1999
LER 98-052-01:on 981128,no Analysis for NSR Sc Manual Loader for Tdafwp Could Be Found in Original Design.Cause Due to All Failure Modes Not Considered When Compressed Air Sys Originally Designed.Performed Review of Components
ML17335A4721999-01-0606 January 1999
LER 98-055-00:on 981207,potential for Condition Outside of Design Bases for Rod Control Sys Was Noted.Caused by Calibration Error Coupled with Single Rod Failure.Condition Rept Investigation Is Ongoing
ML17335A4691999-01-0606 January 1999
LER 98-056-00:on 981211,hot Leg Nozzle Gaps Resulted in Plant Being in Unanalyzed Condition.Analyses Are Being Performed by W to Resolve Problem.Updated LER Will Be Submitted by 990211.With 990106 Ltr
ML17335A4661999-01-0505 January 1999
LER 98-049-00:on 981020,emergency Boron Injection Flow Path Was Inoperable.Caused by Original Design Deficiency. Engineering Evaluation of Event Is Continuing
ML17335A4631999-01-0404 January 1999
LER 98-054-00:on 981202,discovered That at Least One MSSV Had Not Been Reset as Required by Ts.Engineering Is Continuing Review of Extent of Condition for Event.Updated LER Will Be Submitted by 990129.With 990104 Ltr
ML17335A4481998-12-30030 December 1998
LER 98-053-00:on 981130,discovered Use of Inoperable Substitute Subcooling Margin Monitor.Caused by Condition Existing Since Installation of Plant Process Computer in 1992.Updated LER Will Be Submitted.With 981230 Ltr
ML17335A4581998-12-28028 December 1998
LER 98-052-00:on 981128,turbine Driven AFW Pump Speed Controller Failure Mode Occurred.Caused Because Not All Failure Modes Were Considered When Compressed Air Sys Was Originally Designed.Verified Current Design Change Process
ML17335A4281998-12-22022 December 1998
LER 98-051-00:on 981122,reactor Trip Signal from Manual Safety Injection Not Verified as Required by TS Surveillance,Was Discovered.Maintenance Currently Evaluating Significance & Cause of Event
ML17335A4111998-12-17017 December 1998
LER 98-047-00:on 981117,potential for Increase Leakage from Reactor Coolant Pump Seals Was Identified.Util Is Working with W to Resolve Issue.Current Expectations Are to Submit Update to LER by 990215.With 981217 Ltr
ML17335A4141998-12-16016 December 1998
LER 98-058-00:on 981216,postulated High Line Break Could Result in Condition Outside Design Bases for AF Occurred. Caused by Deficiencies Associated with Administration of HELB Program.Analysis of AF Will Be Completed by 990122
ML17335A4181998-12-16016 December 1998
LER 98-050-00:on 980814,ancillary Equipment Installed in Ice Condenser Was Not Designed to Withstand Design Basis Accident/Earthquake Loads.Caused by Lack of Established Design Criteria.Developed Design Criteria
ML17335A3871998-12-11011 December 1998
LER 98-031-01:on 980610,potential Common Mode Failure of RHR Pumps Were Noted.Caused by Inaccurate Values.Accurate Miniflow Numbers Have Been Determined by Flow Testing
ML17335A3821998-12-0808 December 1998
LER 98-039-01 Re EOP Step Conflicts with Small Break LOCA Analysis.Ler 98-039-00 Has Been Canceled.With 981208 Ltr
ML17335A3781998-12-0707 December 1998
LER 98-007-00:on 981106,high Energy Line Break Effects in Auxiliary FW Sys Was Noted.Cause of Event Is Under Investigation & Will Be Completed by 990220.Updated LER Will Be Submitted by 990310.With 981207 Ltr
ML17335A3771998-12-0303 December 1998
LER 98-046-00:on 981103,determined That Afs Was Unable to Meet Design Flow Requirements During Special Test.Caused by Failure to Consider All Aspects of Sys Operation in Design of Suction Basket Strainers.Sys Will Be Redesigned
ML17335A3741998-12-0202 December 1998
LER 97-011-02:on 970822,operation Was Noted Outside Design Bases for ECCS & CSP for Switchover to Recirculation Sump Suction.Caused by Ineffective Change Mgt.Revised Procedure for Switchover 01(02) Ohp 4023.ES-1.3
1999-09-17
[Table view]
Category:TEXT-SAFETY REPORT
MONTHYEARML17335A5641999-10-18018 October 1999
LER 99-024-00:on 990708,literal TS Requirements Were Not Met by Accumlator Valve Surveillance.Caused by Misjudgement Made in Conversion from Initial DC Cook TS to W Std Ts.Submitted License Amend Request.With 991018 Ltr
ML17335A5531999-10-0707 October 1999
LER 99-023-00:on 990907,inadequate TS Surveillance Testing of ESW Pump ESF Response Time Noted.Caused by Inadequate Understanding of Plant Design Basis.Surveillance Tests Will Be Revised & Implemented
ML17335A5631999-09-30030 September 1999
Monthly Operating Rept for Sept 1999 for DC Cook Nuclear Plant,Unit 1.With 991012 Ltr
ML17335A5621999-09-30030 September 1999
Monthly Operating Rept for Sept 1999 for DC Cook Nuclear Plant,Unit 2.With 991012 Ltr
ML17335A5481999-09-30030 September 1999
Non-proprietary DC Cook Nuclear Plant Units 1 & 2 Mods to Containment Sys W SE (Secl 99-076,Rev 3).
ML17335A5451999-09-28028 September 1999
Rev 1 to Containment Sump Level Design Condition & Failure Effects Analysis for Potential Draindown Scenarios.
ML17326A1291999-09-17017 September 1999
LER 99-022-00:on 990609,electrical Bus Degraded Voltage Setpoints Too Low for Safety Related Loads,Was Discovered. Caused by Lack of Understanding of Design of Plant.No Immediate Corrective Actions Necessary
ML17326A1481999-09-17017 September 1999
Independent Review of Control Rod Insertion Following Cold Leg Lbloca,Dc Cook,Units 1 & 2.
ML17326A1211999-08-31031 August 1999
Monthly Operating Rept for Aug 1999 for Cook Nuclear Plant, Unit 2.With 990915 Ltr
ML17326A1201999-08-31031 August 1999
Monthly Operating Rept for Aug 1999 for Cook Nuclear Plant, Unit 1.With 990915 Ltr
ML17326A1121999-08-27027 August 1999
LER 99-021-00:on 990728,determined That GL 96-01 Test Requirements Were Not Met in Surveillance Tests.Caused by Failure to Understand Full Extent of GL Requirements. Surveillance Procedures Will Be Revised or Developed
ML17326A1011999-08-26026 August 1999
LER 99-020-00:on 990727,EDGs Were Declared Inoperable.Caused by Inadequate Protection of Air Intake,Exhaust & Room Ventilation Structures from Tornado Missile Hazards. Implemented Compensatory Measures in Form of ACs
ML17326A0911999-08-16016 August 1999
LER 99-019-00:on 990716,noted Victoreen Containment Hrrms Not Environmentally Qualified to Withstand post-LOCA Conditions.Caused by Inadequate Design Control.Reviewing Options to Support Hrrms Operability in Modes 1-4
ML17326A0771999-08-0404 August 1999
LER 98-029-01:on 980422,noted That Fuel Handling Area Ventilation Sys Was Inoperable.Caused by Original Design Deficiency.Radiological Analysis for Spent Fuel Handling Accidents in Auxiliary Bldg Will Be Redone by 990830
ML17335A5461999-08-0202 August 1999
Rev 0 to Evaluation of Cook Recirculation Sump Level for Reduced Pump Flow Rates.
ML17326A0871999-07-31031 July 1999
Monthly Operating Rept for July 1999 for DC Cook Nuclear Plant,Unit 1.With 990812 Ltr
ML17326A0861999-07-31031 July 1999
Monthly Operating Rept for July 1999 for DC Cook Nuclear Plant,Units 2.With 990812 Ltr
ML17326A0741999-07-29029 July 1999
LER 99-018-00:on 990629,determined That Valve Yokes May Yield Under Combined Stress of Seismic Event & Static,Valve Closed,Stem Thrust.Caused by Inadequate Design of Associated Movs.Operability Determinations Were Performed for Valves
ML17326A0661999-07-26026 July 1999
LER 99-017-00:on 990625,noted That Improperly Installed Fuel Oil Return Relief Valve Rendered EDG Inoperable.Caused by Personnel Error.Fuel Oil Return Valve Was Replaced with Valve in Correct Orientation.With 990722 Ltr
ML17326A0651999-07-22022 July 1999
LER 98-014-03:on 980310,noted That Response to high-high Containment Pressure Procedure Was Not Consistent with Analysis of Record.Caused by Inadequate Interface with W. FRZ-1 Will Be Revised to Be Consistent with New Analysis
ML17326A0491999-07-13013 July 1999
LER 99-016-00:on 990615,TS Requirements for Source Range Neutron Flux Monitors Not Met.Caused by Failure to Understand Design Basis of Plant.Procedures Revised.With 990713 Ltr
ML17326A0331999-07-0101 July 1999
LER 99-004-01:on 971030,failure to Perform TS Surveillance Analyses of Reactor Coolant Chemistry with Fuel Removed Was Noted.Caused by Ineffective Mgt of Tss.Chemistry Personnel Have Been Instructed on Requirement to Follow TS as Written
ML17326A0511999-06-30030 June 1999
Monthly Operating Rept for June 1999 for DC Cook Nuclear Plant,Unit 2.With 990709 Ltr
ML17326A0501999-06-30030 June 1999
Monthly Operating Rept for June 1999 for DC Cook Nuclear Plant,Unit 1.With 990709 Ltr
ML17326A0151999-06-18018 June 1999
LER 99-014-00:on 990521,determined That Boron Injection Tank Manway Bolts Were Not Included in ISI Program,Creating Missed Exam for Previous ISI Interval.Caused by Programmatic Weakness.Isi Program & Associated ISI Database Modified
ML17325B6421999-06-0101 June 1999
LER 99-013-00:on 990327,safety Injection & Centrifugal Charging Throttle Valve Cavitation During LOCA Could Have Led to ECCS Pump Failure.Caused by Inadequate Original Design Application of Si.Throttle Valves Will Be Developed
ML17325B6311999-06-0101 June 1999
LER 99-S03-00:on 990430,vital Area Barrier Degradation Was Noted.Caused by Inadequate Insp & Maint of Vital Area Barrier.Repairs & Mods Were Made to Barriers to Eliminate Degraded & Nonconforming Conditions
ML17326A0061999-05-31031 May 1999
Monthly Operating Rept for May 1999 for Dcp.With 990609 Ltr
ML17326A0071999-05-31031 May 1999
Monthly Operating Rept for May 1999 for DC Cook Nuclear Plant,Unit 2.With 990609 Ltr
ML17325B6351999-05-28028 May 1999
LER 99-S02-00:on 990428,vulnerability in Safeguard Sys That Could Allow Unauthorized Access to Protected Area Was Noted. Caused by Inadequate Original Plant Design.Mods Were Made to Wall Opening to Eliminate Nonconforming Conditions
ML17265A8231999-05-24024 May 1999
LER 98-037-01:on 990422,determined That Ice Condenser Bypass Leakage Exceeds Design Basis Limit.Caused by Pressure Seal Required by Revised W Design Not Incorporated Into Aep Design.Numerous Matl Condition Walkdowns & Assessments Made
ML17325B6001999-05-20020 May 1999
LER 99-012-00:on 990420,concluded That Auxiliary Bldg ESF Ventilation Sys Not Capable of Maintaining ESF Room Temps post-accident.Caused by Inadequate Control of Sys Design Inputs.Comprehensive Action Plan Being Developed
ML17325B5861999-05-10010 May 1999
LER 99-002-00:on 990415,discovered That TS 4.0.5 Requirements Were Not Met Due to Improperly Performed Test. Caused by Incorrect Interpretation of ASME Code.App J Testing Will Be Completed & Procedures Will Be Revised
ML17325B5811999-05-0404 May 1999
LER 99-011-00:on 990407,air Sys for EDG Will Not Support Long Operability.Caused by Original Design Error.Temporary Mod to Supply Makeup Air Capability in Modes 5 & 6 Was Prepared
ML17325B5771999-05-0303 May 1999
LER 99-010-00:on 990401,RCS Leak Detection Sys Sensitivity Not in Accordance with Design Requirements Occurred.Caused by Inadequate Original Design of Containment Sump Level. Evaluation Will Be Performed to Clearly Define Design
ML17335A5301999-04-30030 April 1999
Monthly Operating Rept for Apr 1999 for DC Cook Nuclear Plant,Unit 1.With 990508 Ltr
ML17335A5291999-04-30030 April 1999
Monthly Operating Rept for Apr 1999 for DC Cook Nuclear Plant,Unit 2.With 990508 Ltr
ML17325B5581999-04-16016 April 1999
LER 99-006-00:on 990115,personnel Identified Discrepancy Between TS 3.9.7 Impact Energy Limit & Procedure 12 Ohp 4030.STP.046.Caused by Lack of Design Basis Control.Placed Procedure 12 Ohp 4030.STP.046 on Administrative Hold
ML17325B5471999-04-12012 April 1999
LER 99-009-00:on 990304,as-found RHR Safety Relief Valve Lift Setpoint Greater than TS Limit Occurred.Cause Investigation for Condition Has Not Been Completed.Update to LER Will Be Submitted,Upon Completion of Investigation
ML17325B5321999-04-0707 April 1999
LER 99-S01-00:on 990308,discovered That Lock for Vital Gate Leading to Plant 4KV Switchgear Area Was Nonconforming & Vulnerable to Unauthorized Access.Caused by Inadequate Gate Design & Inadequate Procedures.Mods Are Being Made to Gate
ML17325B5161999-04-0101 April 1999
LER 99-007-00:on 981020,calculations Showed That Divider Barrier Between Upper & Lower Containment Vols Were Overstressed.Engineers Are Currently Working on Analyses of Loads & Stress on Enclosures
ML17325B5491999-03-31031 March 1999
Monthly Operating Rept for Mar 1999 for DC Cook Nuclear Plant Unit 2.With 990408 Ltr
ML17325B5441999-03-31031 March 1999
Monthly Operating Rept for Mar 1999 for DC Cook Nuclear Plant,Unit 1.With 990408 Ltr
ML17325B5221999-03-29029 March 1999
LER 99-001-00:on 960610,degraded Component Cooling Water Flow to Containment Main Steam Line Penetrations,Identified on 990226.Caused by Inadequate Understanding of Design Basis.Additional Investigations Ongoing
ML17325B4801999-03-18018 March 1999
LER 99-004-00:on 971030,failure to Perform TS Surveillance Analyses of Rc Chemistry with Fuel Removed Was Noted.Cause of Event Is Under Investigation.Corrected Written Job Order Activities Used to Control SD Chemistry Sampling
ML17325B4741999-03-18018 March 1999
LER 99-005-00:on 940512,determined That Rt Breaker Manual Actuations During Rod Drop Testing Were Not Previously Reported.Caused by Lack of Training.Addl Corrective Actions,Including Preventative Actions May Be Developed
ML17325B5671999-03-0202 March 1999
Summary of Unit 1 Steam Generator Layup Chemistry from 980101 to 990218.
ML17325B4631999-02-28028 February 1999
Monthly Operating Rept for Feb 1999 for DC Cook Nuclear Power Station,Unit 2.With 990308 Ltr
ML17325B4621999-02-28028 February 1999
Monthly Operating Rept for Feb 1999 for DC Cook Nuclear Plant,Unit 1.With 990308 Ltr
ML17325B4571999-02-24024 February 1999
LER 99-003-00:on 990107,CR Pressurization Sys Surveillance Test Did Not Test Sys in Normal Operating Condition.Caused by Failure to Recognize Door 12DR-AUX415 as Part of CR Pressure Boundary.Performed Walkdown of Other Doors
1999-09-30
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NRCForm366U.S.NUCLEARREGULATORY COMMISSION (6-1998)LICENSEEEVENTREPORT(LER)(Seereverseforrequirednumberofdigits/characters foreachblock)APPROVEDBYOMBNo.3150.0104 EXPIRES06/30/2001 ESTIMATED BURDENPERRESPONSETOCOMPLYWITHTHISMANDATORY INFORMATION COLLECTION REOVESD50.0HRS.REPORTEDLESSONSLEARNEDAREINCORPORATED BJTOTHEUCEJISING PROCESSANDFEDBACKTOINDUSTRY.
FORWARDCOMMENTSREGARDUIG BURDENESTSJATETOTHEII&ORMATION ANORECORDSMANAGEMENT BRANCHIT4AS),V.S.NVCLEARRFGUIATORY COMMISSION.
WASHBJGTON.
OC205S54XI.
ANOTOTHEPAPERWORK REDUCTION PROJECTtst50410l),
OFFICEOFMANAGEMENT ANDBUCGEf,WASIeNGTceL DC2050$FACILITYNAMEI1)CookNuclearPlantUnit1DOCKETNUMBERr2)05000-315 PAGEI5)1of3TITLEI4)Auxiliary BuildingESFVentilation SystemMayNotbeCapableofMaintaining ESFRoomTemperatures Post-Accident MONTH04DAYYEAR201999EVENTDATE(5)YEAR1999LERNUMBER(8)SEQUENTIAL NUMBER012REVISIONNUMBER00REPORTDATE(7)MONTHDAYYEAR05201999ILID.C.Cook,Unit2AILINAM05000-316 DCNUMBEROTHERFACILITIES INVOLVED(8)OPERATING MODE(9)POWERLEVEL(10) 0%20.2201(b)20.2203(a)(1) 20.2203(a)(2)(i) 20.2203(a)(2)(v) 20.2203(a)(3)(i) 20.2203(a)(3)(ii) 50.73(a)(2)(l) 50.73(a)(2)(ii) 50.73(a)(2)(iii) 50.73(a)(2)(viii) 50.73(a)(2)(x) 73.71THISREPORTISSUBMITTED PURSUANTTOTHEREQUIREMENTS OF10CFRII:(Checkoneormore)(11)20.2203(a)(2)(ii) 20.2203(a)(2)(iii) 20.2203(a)(2)(iv) 20.2203(a)(4) 50.36(c)(1) 50.36(c)(2)
LICENSEECONTACTFORTHISLER(12)50.73(a)(2)(iv) 50.73(a)(2)(v) 50.73(a)(2)(vii)
OTHERSpecii/yInAbstractbekrrrornNRCForm366ANAMEMs.BrendaW.O'ourke,Compliance EngineerTELEPHONE NUMBER(IIK5udeAreaCode)(616)465-5901x2604COMPLETEONELINEFOREACHCOMPONENT FAILUREDESCRIBED INTHISREPORT(13).CAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TOEPIXCAUSESYSTEMCOMPONENT MANUFACTURER REPORTABLE TOEPIXSUPPLEMENTAL REPORTEXPECTED(14XYES(IfYes,completeEXPECTEDSUBMISSION DATE)NOEXPECTEDSUBMISSION DATE15MONTH10DAY311999Abstract(Limitto1400spaces,I.e.,approximately 15singie-spaced typewritten lines)(16)OnApril20,1999,duringperformance oftheExpandedSystemReadiness Review(ESRR)fortheAuxiliary BuildingVentilation Systems,itwasconcluded thatthereisinsufficient assurance thattheEngineered SafetyFeaturesVentilation (AES)systemiscapableofperforming itssafetyandaccidentmitigation function.
Thisconclusion wasbasedonapreliminary evaluation ofnumerousidentified systemdeficiencies takenintheaggregate.
Specifically, significant errorsincalculations forauxiliary buildingEngineered SafetyFeaturescubicletemperatures expectedduringpostulated accidentscenarios, vulnerability ofAESdampercontrolairsystemmodification tosinglefailure;andlackofmissileprotection fortheComponent CoolingWaterpumpareasupplyfans.Basedonthecombinedeffectsofthesedeficiencies, theabilityoftheAESsystemtomaintainauxiliary buildingtemperatures towithinsafety-related equipment designtemperatures underaccidentconditions cannotbeassured.Thepreliminary causesforidentified conditions are:inadequate controlofsystemdesigninputs;failuretoadequately implement singlefailuredesigncriteriaduringthemodification process;andlackofacleardefinition indesignandlicensing documents regarding designrequirements forsystemprotection againstmissileeffects.Acomprehensive actionplanisbeingdeveloped todetermine theauxiliary buildingdesigntemperatures requiredtobemaintained bytheAESventilation system.Inaddition, asinglefailureanalysisfortheAESventilation systemwillbeperformed toidentifyfailuresthatcouldpreventthesystemfromperforming itsdesignandsafetyfunction.
Basedontheresultsofthecompleted evaluation, information regarding thesafetysignificance, andcorrective andpreventive actionswillbeprovidedinanupdatetothisLER.9905260279 990520PDRADOCK050003'l5 SPDR
NRCFORM366AU.S.NUCLEARREGULATORY COMMISSION (6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION FACILITYNAME(1)CookNuclearPlantUnit1DOCKETNUMBER(2) 05000-315 YEARLERNUMBER(6)SEQUENTIAL NUMBERREVISIONNUMBERPAGE(3)2of3TEXT(Ifmorespaceisrequired, useadditional copiesofNRCForm(366A)(17)Conditions PriortoEventUnit1wasinMode5,ColdShutdownUnit2wasinMode5,ColdShutdown199901200DescritionofEventOnApril20,1999,duringperformance oftheExpandedSystemReadiness Review(ESRR)fortheAuxiliary BuildingVentilation Systems,itwasconcluded thatthereisinsufficient assurance thattheEngineered SafetyFeaturesVentilation (AES)systemiscapableofperforming itssafetyandaccidentmitigation function.
Thisconclusion wasbasedonapreliminary evaluation ofnumerousidentified systemdeficiencies takenintheaggregate.
Specifically, significant errorsincalculations forauxiliary buildingEngineered SafetyFeatures(ESF)cubicletemperatures expectedduringpostulated accidentscenarios, combinedwithsmalldesignmarginsthatexistedbetweencalculated roomtemperatures anddesignrequirements; vulnerability ofAESdampercontrolairsystemmodification tosinglefailure;andlackofmissileprotection fortheComponent CoolingWater(CCW)pumpareasupplyfanswhichcouldresultinasinglecatastrophic failure-generated missileimpacting bothtrainsofAES.Basedonthecombinedaffectsofthesedeficiencies, theabilityoftheUnit1and2AESsystemstomaintainauxiliary buildingtemperatures towithinsafety-related equipment designtemperatures underallaccidentconditions cannotbeassured.Inaccordance withtherequirements of10CFR50.72(b)(2)(iii)(D),
a4hournotification wasmadetotheNRConApril20,1999,at1645hours,foranyeventorcondition thatalonecouldhaveprevented thefulfillment ofthesafetyfunctionofstructures orsystemsthatareneededtomitigatetheconsequences ofanaccident.
CauseofEventThepreliminary causefortheuseofnon-conservative andincorrect assumptions inauxiliary buildingheatloadcalculations isduetoinadequate controlofsystemdesigninputs.Thisissuewaspreviously identified inAEP:NRC:1260GH, datedMarch19,1999,"Enforcement Actions98-150,98-151,98-152and98-186,ReplytoNoticeofViolation DatedOctober13,1998."Thepreliminary causeforAESdamperdesignsinglefailurevulnerability isfailureofthedesignchangeprocesstoidentifythepotential adverseimpactontheAESsystemcreatedbythemodification tothedampercontrolairsystemin1997.Thepreliminary causeforCCWpumpareasupplyfansusceptibility tomissileeffectsislackofacleardefinition indesignandlicensing documents regarding AESdesignrequirements forprotection againstmissileeffects.AnalsisofEventThisLERissubmitted inaccordance with10CFR50.73(a)(2)(v)(D) foracondition thatcouldpreventthefulfillment ofthesafetyfunctions oftheAESsystemthatareneededtomitigatetheconsequences ofanaccident:
TheAESsystemsafetyandaccidentmitigation functionistoprovidesufficient coolingtotheauxiliary buildinggeneralareasandESFequipment roomsrequiredtooperateduringaccidentconditions.
ThisincludestheCCW,Containment Spray,ResidualHeatRemoval,ChargingandSafetyInjection equipment rooms.TheAESsystemalsomaintains theauxiliary buildingatanegativepressurerelativetotheoutsideenvironment toensureradioactive contamination releasedduringanaccidentiscontained withintheauxiliary
- building, filteredandexhausted totheenvironment viaamonitored, releasepath.Inaddition, Technical Specification 3.7.6.1requiresthattwoindependent AESventilation systemfan/filter exhausttrainsbeoperableinModes1through4.Calculations weredeveloped toestablish theauxiliary buildingheatloads,ESFcubicleroomandgeneralareatemperatures duringnormal,shutdownandaccidentconditions.
DuringtheESRRreviewofthesecalculations, numerousdiscrepancies wereidentified.
Forexample,calculation ofauxiliary buildingareatemperature duringaccidentconditions NRCFORM366A(6-1996)
NRCFORM366AU.S.NUCLEARREGULATORY COMMISSION (6-1998)LICENSEEEVENTREPORT(LER)TEXTCONTINUATION FACILITYNAME(1)CookNuclearPlantUnit1DOCKETNUMBER(2) 05000-315 YEARLERNUMBER(6)SEQUENTIAL NUMBERREVISIONNUMBERPAGE(3)3of3199901200TEXT(ifmorespaceisrequired, useadditional copiesofNRCForm(366A)(17)didnotincludetheheatloadfortheCCWsystempiping.Thisequipment isconsidered asignificant heatloadintheauxiliary buildingandexcluding itfromthecalculation couldresultinnon-conservative auxiliary buildingareatemperature values.Inaddition, thesevaluesserveasinputassumptions tootherauxiliary buildingventilation calculations.
Asaresult,actualauxiliary buildingareaandESFcubicleroomtemperatures couldimpactthequalification oftheESFequipment locatedintheareasservedbytheAESandCCWpumpareaventilation systems.TheAESventilation systemconsistsoftwofan/filter exhausttrains(oneinstandby)whichdrawsairfromtheauxiliary buildingthroughtheequipment cubiclesfromacommonventduct,anddischarges theexhausttotheoutsideatmosphere viatheventstack.Eachtrainconsistsofaroughingfilter,highefficiency particulate air(HEPA)filters,andanormallyclosedpneumatically operatedfacedamper.Inaddition, eachtraincontainsabypassductwithanormallyopenpneumatically operatedbypassdamperwhichdirectsairflowaroundthecharcoaladsorbers.
Duringnormaloperation, onefan/filter unitoperatescontinuously, directing theexhaustairthroughtheroughingandHEPAfilters,bypassing thecharcoalfilters,anddischarging totheunitvent.Thisoperation aidsinairdistribution withintheauxiliary
- building, isolatestheatmosphere inthecubiciesbyinducingadraftthroughtheenteringportalsandremovesanyheatgenerated withintheenclosures.
In1997,amodification tothedampercontrolairsystemincludedtheinstallation ofsolenoidvalvesintheairlinestothefaceandbypassdampers.Duringtheperformance ofsurveillance test12OHP4030STP.25A/8, ontwoseparateoccasions, thefacedampersolenoidvalvefailed,resulting inthefacedamperfailingtoopenwhilethebypassdampersremainedclosed.Fornon-Slinitiated events,afailureofthefacedampersolenoidtoopenthe'facedamperorthebypassdampersolenoidtoopenthebypassdamperinresponsetoacontrolsignalcouldresultinboththefaceandbypass.dampersbeingintheclosedposition, blockingallairflowthroughtheaffectedtrain.IntheeventofaPhaseBIsolation signal,thestandbytrainisenergized andthebypassdampersautomatically closeandthefacedampersopentoexhaustairdirectlythroughthecharcoalfilters,roughingandHEPAfilters.AlthoughthesinglefailureofeitherthebypassorfacedampersolenoidvalvewouldrenderonetrainofAESinoperable, itwouldnotimpactthecapability ofthestandbyfan/filter trainfromperforming itssafetyandaccidentmitigation function.
TheAESsystemdesignincludesthreevaneaxial supplyfanslocatedintheCCWequipment roomwhicharelocatedsidebyside,andconnected toacommonintakeplenumanddischarge duct.Becausevaneaxial fansaresusceptible tofanbladefailures, thefanbladesareapotential missilesourcewhichcouldimpactthefunctionofadjacentsafetyrelatedcomponents.
Asaresult,failureoftheCCWpumpareasupplyfanscouldimpacttheabilityoftheAESsystemtomaintainESFcubicletemperatures towithinequipment designtemperatures, impacting thequalification oftheESFequipment.
Becauseofthenumeroussystemdeficiencies identified duringtheESRR,acomprehensive actionplanisbeingdeveloped toevaluatetheidentified conditions.
Untiltheaggregate effectoftheseconditions onAESsystemperformance isevaluated, theoverallsafetyimpactcannotbedetermined.
Corrective ActionsAcomprehensive actionplanisbeingdeveloped todetermine theauxiliary buildingdesigntemperatures requiredtobemaintained bytheauxiliary buildingventilation systems:Inaddition, asinglefailureanalysisfortheAESventilation systemwillbeperformed toidentifyfailureswhichcouldpreventthesystemfromperforming itsdesignandsafetyfunction.
Basedontheresultsofthecompleted evaluation, additional information regarding safetysignificance, including corrective andpreventive actionswillbeprovidedinanupdatetothisLER.PreviousSimilarEventsLER315/97-023-00 NRCFORM366A(6-1998)