05000318/LER-2022-002, Unplanned Safety Injection Actuation Signal Due to Human Error
| ML22316A019 | |
| Person / Time | |
|---|---|
| Site: |  |
| Issue date: | 11/11/2022 |
| From: | Constellation Energy Generation |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML22316A017 | List: |
| References | |
| LER 2022-002-00 | |
| Download: ML22316A019 (1) | |
| Event date: | |
|---|---|
| Report date: | |
| 3182022002R00 - NRC Website | |
text
Abstract
OnSeptember14,2022,withUnit2inMode5(ColdShutdown)duringcooldownforamaintenanceoutage, OperationscommencedperformanceofOI342,Section6.8/AppendixJ,BypassingSIASandSIASBlockSensor ModulesinMode5,6,orDefueled,insupportofOP052,PlantShutdownfromHotStandbytoColdShutdown.During performanceoftheOI342evolution,anunplannedSafetyInjectionActuationSignal(SIAS)occurredduetoOperator failuretocomplywithstationprocedureuseandadherencestandards.TheunplannedSIASresultedintheautomatic startofthesites2ADieselGenerator(DG)and2BDG.TheunplannedSIASdidnotresultinsafetyinjectionintothe reactorcoolantsystemnordiditadverselyimpactshutdowncoolingoperations.
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(See NUREG-1022, R.3 for instruction and guidance for completing this form http://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
Page 5 of 5 SafetyImpact
Thesafetysignificanceofthiseventwasminimal.Atthetimeoftheevent,Unit2wasinMode5andtheHPSILTOP tagoutwasinplace,preventingtheinjectionofhighpressuremakeupintothereactorcoolantsystemwhileinalow temperaturecondition.BothLPSIPumpswerealreadyinoperationprovidingcoolingflowviatheSDCsystem.SDC operationwasnotadverselyimpactedbytheunplannedSIAS.AlthoughbothUnit2dieselgenerators,the2ADGand 2BDG,receivedautomaticstartsignalsfromtheunplannedSIASAandB,sincetherewasnolossofeitherthe214KV Bus(safetyrelatedZAtrainbussupportedbythe2ADG)orthe244KVBus(safetyrelatedZBtrainbussupportedby the2BDG),neitherofthedieselgeneratorsloadedontotheirrespectivebus.Followingtheautomaticstartofthe2A DGand2BDG,bothdieselgeneratorsoperatedsatisfactorilyuntilsecured.
F.CORRECTIVEACTIONS
TheCAPproductperformedunderIR4522477identifiedthefollowingcorrectiveactionsthatareplannedtobetaken toaddresscauseandextentofconditionfromtheeventinvestigation:
(1)PerformedaCorrectiveActionProgramevaluation.
(2)AddressedpersonnelaccountabilityactionsinaccordancewithHumanResourcepolicies.
(3)ReviseapplicableESFAS/AuxiliaryFeedwaterActuationSystem(AFAS)procedurestoclearlydelineate supervisoryoversightwhileperformingthetasks.
G.PREVIOUSOCCURRENCES
AreviewofCalvertCliffsreportableeventsbacktoJanuary2012wasperformed.TherewerenoLERsthatinvolved unplannedESFASactuationsastheresultofpersonnelerrors.
LER3182021004,Unit2ManualReactorTripDuetoLoweringSteamGeneratorLevels,doesdocumentaUnit2 manualreactortripthatwasinitiatedbyapersonnelerrorwhenbreakerstabcoverswerenotremovedpriorto attemptingtoenergizethe12SpentFuelPoolCoolingPump(SFPCP).Uponattemptingtoenergizethe12SFPCP,an arcflasheventoccurredthatresultedinthelossofthe24A480VLoadCenterthatledultimatelytotheneedfor OperationstomanuallytriptheUnit2reactor.
H.COMPONENTFAILUREDATA
Therewerenocomponentfailuresidentifiedthatcontributedtothiseventoroccurredasaresultofthisevent.