ML17177A576

LER 17-003-00 for Browns Ferry, Unit 1, Regarding Unanalyzed Condition for Tornado Missiles Striking the Emergency Diesel Generator Fuel Oil Vent Lines

ML17177A576
Person / Time
Site:
Issue date:	06/26/2017
From:	Bono S M Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 17-003-00
Download: ML17177A576 (8)

Text

Tennessee ValleyAuthority, PostOfficeBox2000,Decatur,Alabama35609-2000 June26,2017ATTN:DocumentControlDeskU.S.NuclearRegulatory Commission Washington, D.C.20555-0001 10CFR50.73BrownsFerryNuclearPlant,Units1,2,and3RenewedFacilityOperating LicenseNos.DPR-33,DPR-52,andDPR-68NRCDocketNos.50-259,50-260,and50-296

Subject:

LicenseeEventReport50-259/2017-003-00 TheenclosedLicenseeEventReport(LER)providesdetailsofanunanalyzed condition fortornadomissilesstrikingtheEmergency DieselGenerator FuelOilVentLines.TheTennessee ValleyAuthority (TVA)issubmitting thisreportinaccordance withTitle10oftheCodeofFederalRegulations (CFR)10CFR50.73(a)(2)(ii)(B),

asanyeventorcondition thatresultedinthenuclearpowerplantbeinginanunanalyzed condition thatsignificantly degradedplantsafety;and10CFR50.73(a)(2)(v)(A)I(B)/(D),

asanyeventorcondition thatcouldhaveprevented thefulfillment ofthesafetyfunctionofstructures orsystemsthatareneededtoshutdownthereactorandmaintainitinasafeshutdowncondition, removeresidualheat,ormitigatetheconsequences ofanaccident.

Furtherevaluation isunderwaytodetermine iftheBrownsFerryNuclearPlantissusceptible toadditional tornadomissileeffects.Atthistime,WAanticipates theneedtosupplement thisLERwiththeresultsofthatevaluation.

Therearenonewregulatory commitments contained inthisletter.Shouldyouhaveanyquestions concerning thissubmittal, pleasecontactJ.L.Paul,NuclearSiteLicensing Manager,at(256)729-2636.

Respectfully, S.M.BonoSiteVicePresident

Enclosure:

LicenseeEventReport50-259/2017-003-00

-Unanalyzed Condition forTornadoMissilesStrikingtheEmergency DieselGenerator FuelOilVentLines U.S.NuclearRegulatory Commission Page2June26,2017cc(wiEnclosure):

NRCRegionalAdministrator

-RegionIINRCSeniorResidentInspector

-BrownsFerryNuclearPlant ENCLOSURE BrownsFerryNuclearPlantUnit1,2,and3LicenseeEventReport50-259/2017-003-00 Unanalyzed Condition forTornadoMissilesStrikingtheEmergency DieselGenerator FuelOilVentLinesSeeEnclosed NRCFORM366U.S.NUCLEARREGULATORY COMMISSION APPROVEDBY0MB:NO.3150.0104 EXPIRES:03/3112020 (04-2017)

Estimated burdenperresponsetocomplywiththismandatory collection request:80hours.,.'."Reportedlessonslearnedareincorporated intothelicensing processandfedbacktoindustry.

Sendcommentsregarding burdenestimatetotheInformation ServicesBranch(1-2F43),U.S.NuclearRegulatory Commission, Washington, DC20555-0001, orbye-mailtoInfocollects.

Resource@nrc.gov, andtotheDeskOfficer,OfficeofInformation andRegulatory Affairs,NEOB-10202,(3150-0104),

OffceofManagement andBudget,Washington, DC20503.Ifameansusedtoimposeaninformation collection doesnotdisplayacurrently valid0MBcontrolnumber,theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformation collection.

1.FACILITYNAME2.DOCKETNUMBER3.PAGEBrownsFerryNuclearPlant,Unit1050002591OF54.TITLEUnanalyzed Condition forTornadoMissilesStrikingtheEmergency DieselGenerator FuelOilVentLines5.EVENTDATE6.LERNUMBER7.REPORTDATE8.OTHERFACILITIES INVOLVEDSEQUENTIAL FACILITYNAMEDOCKETNUMBERMONTHDAYYEARYEARNUMBERMONTHDAYYEARBrownsFerryNuclear,Unit205000260042520172017-003-0006262017FACILITYNAMEDOCKETNUMBERBrownsFerryNuclear,Unit305000296_________________

9.OPERATING MODE__________________

__________

_____11.THISREPORTISSUBM11EDPURSUANTTOTHEREQUIREMENTS OF10CFR:(Checkallthatapply)El20.2201(b) 020.2203(a)(3)(i) 05073(a)(2)(ii)(A) 050.73(a)(2)(viii)(A) 1020.2201(d) 020.2203(a)(3)(ii) 50.73(a)(2)(ii)(B) 050.73(a)(2)(viii)(B) o20.2203(a)(1)

El20.2203(a)(4)

El50.73(a)(2)(iii) 050.73(a)(2)(ix)(A) o20.2203(a)(2)(i) 050.36(c)(1)(i)(A) 050.73(a)(2)(iv)(A)

El50.73(a)(2)(x)

____________________

10.POWERLEVEL020.2203(a)(2)(ii)

El50.36(c)(1)(ii)(A) 50.73(a)(2)(v)(A) 073.71(a)(4) o202203(a)(2)(iii)

El50.36(c)(2) 50.73(a)(2)(v)(B)

El73.71(a)(5) 100020.2203(a)(2)(iv) 050.46(a)(3)(ii)

El50.73(a)(2)(v)(C)

El73.77(a)(1)

El202203(a)(2)(v)

El50.73(a)(2)(i)(A)

Z50.73(a)(2)(v)(D) 073.77(a)(2)(i)

El202203(a)(2)(vi)

El50.73(a)(2)(i)(B)

El50.73(a)(2)(vii) 073.77(a)(2)(ii) 050.73(a)(2)(i)(C) 0OTHERSpecifyinAbstractbeloworinNRCForm366A12.LICENSEECONTACTFORTHISLERLICENSEECONTACTTELEPHONE NUMBER(IncludeAreaCode)RyanCoons,Licensing Engineer56-729-2070 13.COMPLETEONEUNEFOREACHCOMPONENT FJLUREDESCRIBED INTHISREPORTCAUSESYSTEMCOMPONENT FACTURERREPORTABLE CAUSESYSTEMCOMPONENT FACTURERREPORTABLE N/AN/AN/AN/AN/AN/AN/AN/AN/AN/A14.SUPPLEMENTAL REPORTEXPECTED15.EXPECTEDMONTHDAYYEARYES(Ifyes,complete15.EXPECTEDSUBMISSION DATE)LINOSUBMISSION 08252017BSTRACT(Limitto1400spaces,i.e.,approximately 15single-spaced typewritten fines)Inaccordance withNRCRegulatory IssueSummary(RIS)2015-06,TornadoMissileProtection, adesignandlicensing basisreviewwasperformed toevaluatetheeffectsofexposingsafetyrelatedfeaturestotornadowindloads,depressurization loads,andstrikesfromtornadogenerated missiles.

OnApril25,2017,itwasdiscovered thatatornadomissilestrikecouldpotentially damagetheexposedandunprotected portionoftheD,3A,3B,3C,and3DEmergency DieselGenerator (EDG)fueloilventlines.Thiscouldpotentially fullycrimptheventline,anddisablethetank'svacuumprevention feature.Developing avacuuminthefueloilsystemwouldlimitthefueloilpump'sabilitytotransferfueloilfromthe7daytanktothedaytank,restricting oreliminating thefueloilflowtotheaffectedEDG,whichwouldpreventtheEDGfromfunctioning.

Thedevelopment ofavacuummayalsodamagethe7daytank.Thiscondition isanoriginalplantdesignlegacyissue.Duetothehistorical natureofthisvulnerability, aspecificcausewasnotidentified.

Ihecompensatory measuresimplemented providealternate fueltankventingassoonasatornadowarninghasbeendeclared.

Thisisimplemented byremovingasamplingplugfromeachof7dayfueltankmanholecoversinsidetheD,3A,3B,3C,and3DEDGrooms.NRCFORM366(04-2017)

NRCFORM366AU.S.NUCLEARREGULATORY COMMISSION APPROVEDBY0MB:NO.3150-0104 EXPIRES:3/3112020 (04-2017)

Estimated burdenperresponsetocomplywiththismandatory collection request:80hours.Reportedlessonslearnedareincorporated intothelicensing processandfedbacktoindustry.

SendLICENSEEEVENTREPORT(LER)commentsregarding burdenestimatetotheInformation ServicesBranch(T-2F43),U.S.NuclearCONTINUATION SHEETRegulatory Commission, Washington, DC20555-0001, orbye-mailtolnfocollects.Resoercenrc.gov, andtotheDeskOfficer,OfficeofInformation andRegulatory Affairs,NEOB-10202,(3150-0104),

OfficeofManagement andBedget,Washington, DC20503.Ifameansusedtoimposeaninformation collection doesnotdisplayacurrently valid0MBcontrolnumber,theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformation collection.

1.FACILITYNAME2.DOCKETNUMBER3.LERNUMBER YEARSEQUENTIAL REVNUMBERINO.BrownsFerryNuclearPlant,Unit105000-259 2017-003-00NARRATIVE I.PlantOperating Conditions BeforetheEventAtthetimeofdiscovery, BrownsFerryNuclearPlant(BFN),Units1,2,and3,wereinMode1at100percentpower.ILDescription ofEventA.EventSummaryInaccordance withNRCRegulatory IssueSummary(RIS)2015-06,TornadoMissileProtection (TMP),adesignandlicensing basisreviewwasperformed toevaluatetheeffectsofexposingsafetyrelatedfeaturestotornadowindloads,depressurization loads,andstrikesfromtornadogenerated missiles.

OnApril25,2017,itwasdiscovered duringthisevaluation thatdamagetotheexposedandunprotected portionoftheD,3A,3B,3C,and3DEmergency DieselGenerator (EDG)[DC]fueloilventlines[VLR]byatornadomissilestrikehasthepotential tofullycrimptheventline,whichwouldrenderthevacuumprevention featureineffective.

Developing avacuuminthefueloilsystem[DE]wouldlimittheabilityofthefueloilpumps[P]totransferfueloilfromthe7daytank[TK]tothedaytank.Thiswouldrestrictoreliminate theflowoffueloiltotheaffectedEDG,whichwouldpreventtheEDGfromfunctioning.

Adevelopment ofavacuummayalsodamagethe7daytank.B.Statusofstructures, components, orsystemsthatwereinoperable atthestartoftheeventandthatcontributed totheeventTherewerenostructures, systems,orcomponents whoseinoperability contributed tothiscondition.

C.Datesandapproximate timesofoccurrences Dates&Approximate TimesOccurrence April25,2017,TheD,3A,3B,3C,and3DEDGsweredeclaredat1630CDTinoperable following anengineering evaluation ofTMP,whichfoundthattheEDG7daytankventpipingissubjecttopotential damage.April25,2017,Inaccordance withNRCEnforcement Guideat1631CDTMemorandum (EGM)15-002,Revision1,Enforcement Discretion forTornado-Generated MissileProtection Non-Compliance, initialcompensatory measureswereimplemented whichprovideadditional protection andlessentornadomissileeffects.NRCFORM366A(04-2017)

Page2of5 NRCFORM366AU.S.NUCLEARREGULATORY COMMISSION APPROVEDBY0MB:NO.3150-0104 EXPIRES:313112020 (04-2017)

Estimated burdenperresponsetocomplywiththismandatory collection request:80hours.Reportedlessonslearnedareincorporated intothelicensing processandfedbacktoindustry.

SendLICENSEEEVENTREPORT(LER)commentsregarding burdenestimatetotheInformation ServicesBranch(T-2F43),U.S.NuclearCONTINUATION SHEETRegulatory Commission, Washington, DC20555-0001, orbye-mailtolnfocollects.Resource@nrc.gov, andtotheDeskOfficer,OfficeofInformation andRegulatory Affairs,NEOB-10202,(3150-0104),

OfficeofManagement andBudget,Washington, DC20503.Ifameansusedtoimposeaninformation collection doesnotdisplayacurrently valid0MBcontrolnumber,theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformation collection.

1.FACILITYNAMEI2.DOCKETNUMBERI3.LERNUNIBER YEARSEQUENTIAL REVNUMBERNO.BrownsFerryNuclearPlant,Unit105000-259 2017-003-00Dates&Approximate TimesOccurrence April25,2017,TheD,3A,3B,3C,and3DEDGsweredeclaredat1647CDTOperableatthistime.April25,2017,TheNRCwasnotifiedoftheunanalyzed condition thatat1653CDTsignificantly degradedplantsafety.D.Manufacturer andmodelnumberofeachcomponent thatfailedduringtheeventThiscondition didnotinvolveanyequipment failure.E.Othersystemsorsecondary functions affectedNoothersystemsorsecondary functions wereaffectedbythiscondition.

F.Methodofdiscovery ofeachcomponent orsystemfailureorprocedural errorThiseventdidnotinvolvetheactualfailureofplantequipment.

However,anunanticipated potential forfailurewasdiscovered onApril25,2017,aspartofadesignandlicensing basisreviewtoevaluatetheeffectsoftornadosandtornadomissilesonsafetyrelatedfeatures, inaccordance withRIS2015-06.G.Thefailuremode,mechanism, andeffectofeachfailedcomponent Thiscondition didnotinvolvetheactualfailureofplantequipment.

H.OperatoractionsTherewerenooperatoractionsassociated withthiscondition.

I.Automatically andmanuallyinitiated safetysystemresponses Therewerenoautomatic ormanualsafetysystemresponses associated withthiscondition.

Ill.CauseoftheeventA.Causeofeachcomponent orsystemfailureorpersonnel errorThiscondition isanoriginalplantdesignlegacyissue.Duetothehistorical natureofthisvulnerability, aspecificcausewasnotidentified.

B.Cause(s)andcircumstances foreachhumanperlormance relatedrootcauseTherewerenohumanperformance relatedrootcausesforthiscondition.

NRCFORM366A(04-2017)

Page3of5 NRCFORM366AU.S.NUCLEARREGULATORY COMMISSION APPROVEDBY0MB:NO.3150-0104 EXPIRES:3/31/2020 (04-2017)

Estimated burdenperresponsetocomplywiththismandatory collection request:80hours.Reportedlessonslearnedareincorporated intothelicensing processandfedbacktoindustry.

SendLICENSEEEVENTREPORT(LER)commentsregarding burdenestimatetotheInformation ServicesBranch(T-2F43),U.S.NuclearCONTINUATION SHEETRegulatory Commission, Washington, DC20555-0001, orbye-mailtolnfocollects.Resourcenrc.gov, andtotheDeskOfficer,OfficeofInformation andRegulatory Affairs,NEOB-10202,(3150-0104),

OfficeofManagement andBudget,Washington, DC20503.Ifameansusedtoimposeaninformation collection doesnotdisplayacurrently valid0MBcontrolnumber,theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformation collection.

1.FACILITYNAMEI2.DOCKETNUMBERI3.LERNUMBER YEARSEQUENTIAL REVINUMBERINO.BrownsFerryNuclearPlant,Unit105000-259 2017-003-00IV.AnalysisoftheeventTheTennessee ValleyAuthority (TVA)issubmitting thisreportinaccordance withTitle10oftheCodeofFederalRegulations (CFR)50.73(a)(2)(ii)(B),

asanyeventorcondition thatresultedinthenuclearpowerplantbeinginanunanalyzed condition thatsignificantly degradedplantsafety;and10CFR50.73(a)(2)(v)(A)/(B)/(D),

asanyeventorcondition thatcouldhaveprevented thefulfillment ofthesafetyfunctionofstructures orsystemsthatareneededtoshutdownthereactorandmaintainitinasafeshutdowncondition, removeresidualheat,ormitigatetheconsequences ofanaccident.

Thecondition wasdiscovered onApril25,2017,at1630CDT,whenanengineering evaluation ofTMPdetermined thatthe7daytankventpipingissubjecttopotential damagefortheD,3A,3B,3C,and3DEDGsrendering theEDGsinoperable forpotential tornadomissileprotection.

Anactualtornadomissileeventcouldhavecausedasafetysystemfunctional failureduetotheinoperability ofmultipleEDGs.However,compensatory measureswereestablished toprovideadditional protection foralleviating tornadomissileeffects,inaccordance withEGM15-002,Revision1.Theseinitialcompensatory measuresallowedtheaffectedEDGstobeconsidered Operablebutnonconforming.

Furtherevaluation isunderwaytodetermine ifBFNissusceptible toadditional tornadomissileeffects.Atthistime,WAanticipates theneedtosupplement thisLERwiththeresultsofthatevaluation.

V.Assessment ofSafetyConsequences TheexposedportionofthefueloilventlinesfortheD,3A,3B,3Cand3DEDGsarenotprotected fromatornadogenerated missilestrike.Anexposedportionofafueloilventlinecouldexperience crimpingdamagesuchthatitcannotperformitsfunctiontopreventthedevelopment ofavacuuminthefueloilsystem.Thedevelopment ofavacuuminthefueloilsystemwouldrenderthefueloiltransfersystemfromthe7daytanktothedaytankineffective.

TheaffectedEDG(s)wouldbeunabletofunctionduetolackoffueloil.TopreventtornadomissileinducedEDGinoperability, BFNOperations personnel arenowprocedurally requiredtoopenanalternate ventilation pathontheEDG7dayfueltanksfollowing thedeclaration ofatornadowarning.Thiscondition hadnoactualsafetyconsequences impacting plantorpublicsafetybecauseBFNdidnotexperience anactualtornadomissileevent;however,thecompensatory actionsthathavebeenimplemented intheSevereWeatherprocedure willmanagethiscondition's risktothehealthandsafetyofthepublic.A.Availability ofsystemsorcomponents thatcouldhaveperformed thesamefunctionasthecomponents andsystemsthatfailedduringtheeventThiscondition didnotresultinanyactualsystemorcomponent failures.

NRCFORM366A(04-2017)

Page4of5 NRCFORM366AU.S.NUCLEARREGULATORY COMMISSION APPROVEDBY0MB:NO.3150-0104 EXPIRES:3/3112020 (04-2017)

Estimated burdenperresponsetocomplywiththismandatory collection request:80hours.Reportedlessonslearnedareincorporated intothelicensing processandfedbacktoindustry.

SendLICENSEEEVENTREPORT(LER)commentsregarding burdenestimatetotheInformation ServicesBranch(T-2F43),U.S.NuclearCONTINUATION SHEETRegulatory Commission, Washington, DC20555-0001, orbye-mailtolnfocollects.Resourcenrc.gov, andtotheDeskOfficer,OfficeofInformation andRegulatory Affairs,NEOB-10202,(3150-0104),

OfficeofManagement andBudget,Washington, DC20503.Ifameansusedtoimposeaninformation collection doesnotdisplayacurrently valid0MBcontrolnumber,theNRCmaynotconductorsponsor,andapersonisnotrequiredtorespondto,theinformation collection.

1.FACILITYNAMEI2.DOCKETNUMBERI3.LERNUMBER YEARISEQUENTIAL REVNUMBERINO.BrownsFerryNuclearPlant,Unit105000-259 2017-003-00B.Foreventsthatoccurredwhenthereactorwasshutdown,availability ofsystemsorcomponents neededtoshutdownthereactorandmaintainsafeshutdownconditions, removeresidualheat,controlthereleaseofradioactive

material, ormitigatetheconsequences ofanaccidentThiscondition didnotoccurduringashutdown.

C.Forfailurethatrenderedatrainofasafetysysteminoperable, estimateoftheelapsedtimefromdiscovery ofthefailureuntilthetrainwasreturnedtoserviceThiscondition isanoriginalplantdesignlegacyissue.Duetothehistorical natureofthisvulnerability, aspecificcausewasnotidentified.

Initialcompensatory measurestorestoreoperability wereimplemented within17minutesofdiscovering thecondition.

VI.Corrective ActionsCorrective ActionsarebeingmanagedbyTVA'scorrective actionprogramunderCondition Report(CR)1288222.A.Immediate Corrective ActionsAnoperatorworkaround wasimplemented toprovideanalternate fueltankventingassoonaspossiblefollowing atornadoevent.B.Corrective ActionstoPreventRecurrence ortoreducetheprobability ofsimilareventsoccurring inthefutureThecomprehensive compensatory measuresincludedrevisingtheSevereWeatherprocedure toincluderemovingasamplingplugoneachoftheEDG7dayfueloiltankstoprovideanalternate ventilation pathwhenatornadowarninghasbeendeclared.

Thesecomprehensive compensatory measureswillremaininplaceuntilthevulnerability ispermanently resolved.

VII.PreviousSimilarEventsattheSameSiteAsearchoftheBFNCorrective ActionProgramidentified nosimilarconditions thathaveoccurredatBFN.VIII.Additional Information Thereisnoadditional information.

IX.Commitments Therearenonewcommitments.

NRCFORM366A(04-2017)

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