ML18037A174

LER 79-012/01T-0 on 790523:concrete Anchor Bolt Deficiencies & Missing Seismic Restraints Were Discovered on Class I Seismic Piping Sys.Caused by Incorrect Installation.Concrete Anchor Bolt Repair Program Will Be Completed by 791231

ML18037A174
Person / Time
Site:	Nine Mile Point
Issue date:	05/31/1979
From:	DUDA E NIAGARA MOHAWK POWER CORP.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML17053A719	List: ML17053A718 ML18037A174
References
LER-79-012-01T, LER-79-12-1T, NUDOCS 7906130006
Download: ML18037A174 (10)

Text

-LICENSEEEVENTREPORTCONTROLOLOCK:(PLEASEPAINTORTYLLAEOUIREOINFORMATION)~ol8CON'T~o~or~o~0~4NYNMP9LICEHSEECODE2Q>'o0-onn1118LICEHSEHUMBE>tSeeAttachediootLLLQo0500022060fnIDOCKETt>UVBEAtent09EVENTDESCRIPTIONANDPROBABLECONSEQUENCES10QQIleft.sfTire30BrCATs83~$0Q'VEHTDATE)4)sAEPOBTDATE80~oo)8960)8rSeeAttachedSYS1EMCAVSECAUSEcn"pvhtvcCODECODESVBCODCCOMI'OMEMTCODESUBCODESUBCt>OE.~oo~Z~ZQ>>~BQ>>~CO>XXXXXXQ>n~ZQ>"~zQ>o91011.121318.19,~70.SEOUEI>TIALoccvAnftlccncronlAEvlsloftLEAnocvEHTYEhflflEPOBTMO.CODETvrc'O,Q>>n>non>~79~~~;022~~.~py~T~~p2223242)282933.AOT>ok,fvfvnE"EFFEcTs<<ufoow'.tATTAC<<LIEHTt'PAD4r>IIL!Eco>!r.COMPO>tfHTTAKE>tAC'I>O>IOMI'LAMTME'l>IOD<<OURS~22SUBVITTEDFOB>'.EUB.SvtrlIC>ltohkUFACTUBC>t>>Q>o~>>Q>o~ZQ>o~2Q>>0000~YQoo~NQ>n~xQ2"G2Qoo333b384041424)444)CAUSEDESCRIPTIONANDCORRECTIVEACTIONS2)0nlZEHNhf>IEOFPllEPAAEAE.Duda~>4)89fACILITYSTATUS5IPOWEBOT>ISBSTATVS.0Q>oNA)89IP12I144ACTIVITVCvtllfkfACLCASfnOFAELEASEAMOUMTOrACTIVITY39Qiana~zQ>ozQ>>NA)0910PCASO<<t>ELEKPOSUBCSMUUPCATYPf.DCSCAIPTIOM~000Qo>~ZQ>Nn).89111713PEAsokt>'ELIt>>un>cstn>veenncscn>pllo>>041OQoNn)891112I.OSSOfOflOAL'AO>L10FACILITYTYPf:DlSC>l>P'IIO>lo~zQa>NA)8910PUBLIC>>YISSUEDnlScn>PTIOM""n~NQ>nNA89IPL>CTIIODOFDISCOVEfIV~CQ>>LOCATIOMOf'CLEASCvooexSQoolo,,NACL)SEONLYBB09PIIONE:3l>-"l132110ThxIr-nsiC>nl30C1DISCOVERYDESCBIpTIOM032AnchorBoltInsection6000Mo'0o0a>>

Igtjffgfl EVENTDESCRIPTIONANDPROBABLECONSEQUENCESAninspectionandtestprogramperNuclearRegulatoryCommissionI.E.Bulletin7902iscurrentlybeingimplementedat.NineMilePointUnit1.TheattachedTableshowsthestatusofthisprogram.ThefollowingdeficienciesinregardtoconcreteanchorboltswerefoundonClassIseismicpipingsystems:1)Boltsloose,missingorcutandweldedtotheundersideofplates2),Oversizedplateholes3)Skewedbolts4)Otherboltsandplateinstallationdeviations5)Missingseismicrestraints.Withtheexceptionofthemissingseismicrestraints,itisourjudgmentthattheconsequencesofthesedeficienciesarerelativelyminorduetothesubstantialmarginspresentinbothbaseplatesandpipingsystemoriginaldesigns.Inmostcases,theeffectsofskewedboltsandoversizedplateholesarebelievedto.bewithintheoriginaldesignmargins(includingfactorsofsafetyasdiscussedinBulletin79-02).Forplateswithmissingbolts,rigidplateanalyseswouldshowthatmostloadswouldnot.'esubstantiallybelowthesafetyfactorsdiscussedinBulletin79-02.Therefore,withoutflexibleplateeffects,theNineMilePointUnit1.repairprogramwouldbereduced.Duringtheevaluationeffort,flexibleplateeffectsasdescribedinBulletin79-02wereincluded.Thisincreasedthecalculatedworkingloadsonanchorboltsresultinginaincreaseinthoseneedingrepair.NiagaraMohawkbelievestheflexibleplateeffectsaresomewhatoverstated.Becauseofthis,NiagaraMohawkbelievesthedeficienciesdiscoveredwouldnotsignificantlyeffecttheoperationofClassIseismicpipingsystemsduringaccidentconditions.

EVENTDESCRIPTIONANDPROBABLECONSEQUENCES(Continued)Withregardtothemissingseismicrestraints,approxi-mately22restraintsincludedonNiagaraMohawkconstructiondrawingsarenotinstalled.AllthemissingrestraintsareoutsidethedrywellontheContainmentSpraySystem.TheconsequencesonoperationoftheContainmentSpraySystemareunknown.SinceNiagaraMohawkplanstoaddrestraints,theeffectswillnotbecalculated.

CAUSEDESCRIPTIONANDCORRECTIVEACTIONThecauseoftheidentifiedconcreteanchorbolt.deficien-ciesandmissingrestraintsareduetoincorrectinstallation.Loose,missingorweldedboltswillbereplaced.Nasherswillbeweldedtobaseplatestoaccount.foroversizedholes.Beveledwasherswillbeusedtocorrectskewedbolts.Restraintandplatemodificationswillbemadetocorrectotherdeficiencies.AdditionalseismicrestraintswillbeinstalledontheContainmentSpraySystemtoassureoriginaldesigncriteriaaremet.FlexibleplateeffectsasdiscussedinBulletin79-02willbeincludedinNiagaraMohawk's.repairprogram.Thefollowingwillbeaccomplishedpriortoplantstartup:1)Repairswillbemadetoalldeficienciesinareaswhichareinaccessibleduringplantoperation.2)ConcreteanchorboltsontheseinaccessiblebaseplateswillbepulltestedtoassureadequatefactorsofsafetyexistsinaccordancewithBulletin79-02.3)RepairswillbemadetoalldeficienciesintheCoreSpray,EmergencyCondenserandControlRodDriveSystems.4)SeismicrestraintswillbeaddedtotheContainmentSpraySystemtoassurestressesarewithinallowablevalues.BeforeDecember31,1979,NiagaraMohawkwillcompletetheinspection,testingandrepairprogramforallconcreteanchorboltsonClassIseismicpipingsystems.

ks SUMMARYTABLEOPINSPECTIONPROGRAMFORBASEPLATESANCHOREDINCONCRETEHighEnergySystemsIncludingMainSteam44Feedwater,EmergencyCondenserandControlRodDriveSystemsIofPlates357327116IofIofPlates2PlatesWith3OtherSafetyRelatedSystemsWhichHaveBeenInspectedIncludingCoreSpray,ReactorInstrumentation,ShutdownCooling,LiquidPoison,CondensateTransfer,ReactorBuildingCloseLoopCooling,andContainmentSpraySystems776729130OtherSafetyRelatedSystemsWhichHaveNotBeen5InspectedIncludingCleanup,VacuumRelief,DieselGeneratorCooling,InstrumentAir,DieselGeneratorStartingAir,N2,VentandPurgeandDrywellInstrumentationSystems1581Averageof4boltsperbaseplateTO'ZAL12911056246~220%ofthosebaseplatesinspectedhavebeenpulltestedwith'onlyonefailedboltasofJune4,1979.343repairshavebeenmadeasofJune4,1979.Althoughtherepairsmayrequireacompletenewbaseplate,thedeficiencymayonlybewithonebolt.4Allbaseplates5TheContainment~.44-p4~4-Q~1anchoredinconcreteintheMainSteamandFeedwaterSystemsarenon-safetyrelated.AtmosphereDilutionSystemisnotincludedsincethiswasinstalledandinspectedl).I 0ri