ML17037C098

Nine Mile Point Unit 1 - Letter Regarding a Problem with the Electromagnetic Relief Valves Disclosed During the Annual Inspection Outage

ML17037C098
Person / Time
Site:	Nine Mile Point
Issue date:	06/02/1972
From:	Burt P A Niagara Mohawk Power Corp
To:	Skovholt D J US Atomic Energy Commission (AEC)
References
Download: ML17037C098 (8)

Text

AECDISTRIBUTION FORPART0DOCKETMATERIALTEMPORARY FORMCONTROLNo:FROM:NiagaraMohawkPlex,Corporation

~Syracuse~

N.Y.13202P.AllisterBurt6-2<<26-8-2DATEOFDOC:DATEREC'DMEMOTO0Mr.SovholtORIG'CSENTAECPDRSENTLOCALPDRCLASS'PROPINFONoCYSREC'DDOCKETNo:DESCRIPTION:

Ltrreporting anincidenton6-2-72,regarcLin alproblem withtheelectromatic reliefvalves8etransthefollowing:

PLANTNAMES:NineMilePointENCLOSURES:

Consolidated.

Electromatic Reli'efValve6"-Type1525-VX(Drawing)

DONOTREMOVE<X<@IILaNB (40cysofenclrec'd)BUTLERLW/CopiesCLARK(L)W/CopiesGOLLER(r,)

W/Copies~G.ZXLEAEcPDalrSEGOPER(2)OGC-RMP-506vYiUNTZING's SZAFFGIAMBUSSO-L BOYD-L-BWR DEYOUNG-L-PWR MULLER-L-ENVXRO SKOVHOLT-L-OPER v'KNUTH-L

~MACCARY-L

-~SCHROEDER-L

~-LOCALPDRKNIELLW/CopiesSCHWENCER(L

)W/CopiesSTOLZ(L)W/Copies@TELLO-L"kOORE-LLANGE-LPAWLICKI-L

~OMPSON-L

~ESCO-LALONG>>LMINAS>>LSHAO-LBENAROYA-L ACORRIS-Ro DUBE-LCASE-LFORACTIONINFORMATION VASSALLOLW/CopiesH.DENTONW/CopiesSCHEMEL(L

)W/CopiesINTERNALDISTRIBUTION vVOLLMERL"BENTON-L (4)GRIMES-LGAMMILL<<L KNIGHTON-ENVIRO DICKER-ENVIRO PROJLDRENVIRO:SALTZMAN-IND.

McDONALD-PLANS NUSSBAUMER-FM SMILEY-FM P.COLLINS-L EXTERNALDISTRIBUTION CHITWOOD(FM)W/CopiesDICKER(ENVIao)

W/CopiesW/CopiesW/CopiesKARAS-LLAPWRMASON-LL/ABWRBROWN-LL/APWRWILSON-LL'/APWRKARI-LL/ABWRSMITH-LL/ABWRGEARXN-LL/ABWRDIGGS-LL/ATEETS-LL/AWADE-LL/AENVXROBRAITMAN-A/T HARLESS-ENVIHO 1-SANLANY--PDRZXEMANNL,,KNIGHTONENVIRO,W/9CopiesW/Copies<1-DTXE-(LAUGHLIN

)<1-NSIC-(BUCHANAN) 1-ASLB-YoaE/SAaYE WOODWARD/H.

ST.1-C.MILES-C-459)

GTV16CYSACRS-HOLDING 9-NATIONAL LAB'1-CHIEFWATERREACTORSANL/ORNL/BNWL 1-RD.~~.E.HALLF-309GT1-R.CARROLL-OCp GT1-RoCATLINpA>>170pGT1-CONSULTANT

'NEWMARK/BLUME/AGBABIAN 1-Da.GERALDS.LELLOUCHE BROOKHAVEN NATXONALLAB

~p4fat0Al-,LaCt~*l(")~~

NIAGARAMOHAWKPOWERCORPORATION

~~)$)lil&.,NIAGARA',MOHAWKNineMilePointNuclearStationPostOfficeBox32Lycoming, NewYork13093June2,1972Mr.DonaldJ.SkovholtAssistant DirectorforReactorOperations DivisionofReactorLicensing UnitedStatesAtomicEnergyCommission Washington, D.C;20545

DearMr.Skovholt:

Re:Provisional Operating License:DPR-17DocketNo.:50-220ODuringtheannualinspection outageofNineMilePointUnit¹1,whichwillterminate

tomorrow, June3,1972,aproblemwiththeelectromatic reliefvalveswasdisclosed.

There'arethree6"Consolidated Electromatic ReliefValves,Type1525-VX,installed oneachofthetwosteamlineswithinthedrywellforatotalofsix.Threearerequiredfordepressurization onlossofcoolantaccidentandfivearerequiredtomaintainpressuremarginbetweenpeaktransient pressureandlowestsafetyvalvesettingonturbinetripwithoutbypass.Ononevalve,thelockingscrew,Part¹8onencloseddrawing,hadbecomeunscrewed allowinglockretainerPlate¹7tofallfree(bothpartswererecovered intheturbinestopvalvestrainerbasket).Thispermitted thediscretainer, Part¹6,tocompletely back-outfallingtothebottomofthevalvebody.Inthiscondition, itwouldbeimpossible tobleedenoughsteamfromChamber"C"toopenthevalveasitwouldbewideopentoChamber"A"andwouldnothavethebenefitoftherestricting orificeintheretainerplate.Oneothervalvewasfoundwiththelockingscrew,Part¹8,backedout1/16"butthelockretainerplateanddiscretainerhadnotmoved,therefore thevalvewasoperable.

Tie-wires holdingthelockingscrewswerebrokenonallsixvalves.

O.r Mr.DcealdJ.SkovholtJune2,1972Repairwaseffectedtoallsixvalvesbyremovingthelockingscrew,Part¹8,andlockretainerplate,Part¹7.Intheirplace,four1/4"Vgrooves,1"long,werecutinthejointbetweenthediscretainerandthevalvebodyinsert.Thesewerestitchweldedtogether, Futuremaintenance maybeaccomplished bygrindingoutthestitchweld.Inthismanner,therecanbenoloosepartsonthevalvestodropintothesteamlinesanddependability ofvalveoperation isincreased.

Verytrulyyours,P.AllisterBurtGeneralSuperintendent NuclearGeneration PAB:pwEnclosure IIJ 212220IS231817161514PORTF12lltIewStitchWeld4PlacesE252627928CONSOLIDATED ELECTROMATIC RELIEFVALVE6"-TYPE1525-VXEffectedParts¹4ValveDisc.¹6DiscRetainer¹7LockRetainerPlate¹8LockingScrewWhennormallyclosed,steampressureisequalinChambers"A","B"and"C".Disc4isheldtoseatbygreaterforcein"C"over"B"(difference inprojected areas)andspring.Valveoperateswhenpressurein"C"isdecreased byopeningofpilotvalve.Highertotalforcein"B"thenpushesDisc4awayfromseatallowingsteamtodischarge.

~>~li~r(.rlt)~\E