ML17037C098
| 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
AECDISTRIBUTIONFORPART0DOCKETMATERIALTEMPORARYFORMCONTROLNo:FROM:NiagaraMohawkPlex,Corporation~Syracuse~N.Y.13202P.AllisterBurt6-2<<26-8-2DATEOFDOC:DATEREC'DMEMOTO0Mr.SovholtORIG'CSENTAECPDRSENTLOCALPDRCLASS'PROPINFONoCYSREC'DDOCKETNo:DESCRIPTION:Ltrreportinganincidenton6-2-72,regarcLinalproblemwiththeelectromaticreliefvalves8etransthefollowing:PLANTNAMES:NineMilePointENCLOSURES:Consolidated.ElectromaticReli'efValve6"-Type1525-VX(Drawing)DONOTREMOVE<X<@IILaNB(40cysofenclrec'd)BUTLERLW/CopiesCLARK(L)W/CopiesGOLLER(r,)W/Copies~G.ZXLEAEcPDalrSEGOPER(2)OGC-RMP-506vYiUNTZING'sSZAFFGIAMBUSSO-LBOYD-L-BWRDEYOUNG-L-PWRMULLER-L-ENVXROSKOVHOLT-L-OPERv'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-LACORRIS-RoDUBE-LCASE-LFORACTIONINFORMATIONVASSALLOLW/CopiesH.DENTONW/CopiesSCHEMEL(L)W/CopiesINTERNALDISTRIBUTIONvVOLLMERL"BENTON-L(4)GRIMES-LGAMMILL<<LKNIGHTON-ENVIRODICKER-ENVIROPROJLDRENVIRO:SALTZMAN-IND.McDONALD-PLANSNUSSBAUMER-FMSMILEY-FMP.COLLINS-LEXTERNALDISTRIBUTIONCHITWOOD(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/THARLESS-ENVIHO1-SANLANY--PDRZXEMANNL,,KNIGHTONENVIRO,W/9CopiesW/Copies<1-DTXE-(LAUGHLIN)<1-NSIC-(BUCHANAN)1-ASLB-YoaE/SAaYEWOODWARD/H.ST.1-C.MILES-C-459)GTV16CYSACRS-HOLDING9-NATIONALLAB'1-CHIEFWATERREACTORSANL/ORNL/BNWL1-RD.~~.E.HALLF-309GT1-R.CARROLL-OCpGT1-RoCATLINpA>>170pGT1-CONSULTANT'NEWMARK/BLUME/AGBABIAN1-Da.GERALDS.LELLOUCHEBROOKHAVENNATXONALLAB
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NIAGARAMOHAWKPOWERCORPORATION~~)$)lil&.,NIAGARA',MOHAWKNineMilePointNuclearStationPostOfficeBox32Lycoming,NewYork13093June2,1972Mr.DonaldJ.SkovholtAssistantDirectorforReactorOperationsDivisionofReactorLicensingUnitedStatesAtomicEnergyCommissionWashington,D.C;20545
DearMr.Skovholt:
Re:ProvisionalOperatingLicense:DPR-17DocketNo.:50-220ODuringtheannualinspectionoutageofNineMilePointUnit¹1,whichwillterminatetomorrow,June3,1972,aproblemwiththeelectromaticreliefvalveswasdisclosed.There'arethree6"ConsolidatedElectromaticReliefValves,Type1525-VX,installedoneachofthetwosteamlineswithinthedrywellforatotalofsix.Threearerequiredfordepressurizationonlossofcoolantaccidentandfivearerequiredtomaintainpressuremarginbetweenpeaktransientpressureandlowestsafetyvalvesettingonturbinetripwithoutbypass.Ononevalve,thelockingscrew,Part¹8onencloseddrawing,hadbecomeunscrewedallowinglockretainerPlate¹7tofallfree(bothpartswererecoveredintheturbinestopvalvestrainerbasket).Thispermittedthediscretainer,Part¹6,tocompletelyback-outfallingtothebottomofthevalvebody.Inthiscondition,itwouldbeimpossibletobleedenoughsteamfromChamber"C"toopenthevalveasitwouldbewideopentoChamber"A"andwouldnothavethebenefitoftherestrictingorificeintheretainerplate.Oneothervalvewasfoundwiththelockingscrew,Part¹8,backedout1/16"butthelockretainerplateanddiscretainerhadnotmoved,thereforethevalvewasoperable.Tie-wiresholdingthelockingscrewswerebrokenonallsixvalves.
O.r Mr.DcealdJ.SkovholtJune2,1972Repairwaseffectedtoallsixvalvesbyremovingthelockingscrew,Part¹8,andlockretainerplate,Part¹7.Intheirplace,four1/4"Vgrooves,1"long,werecutinthejointbetweenthediscretainerandthevalvebodyinsert.Thesewerestitchweldedtogether,Futuremaintenancemaybeaccomplishedbygrindingoutthestitchweld.Inthismanner,therecanbenoloosepartsonthevalvestodropintothesteamlinesanddependabilityofvalveoperationisincreased.Verytrulyyours,P.AllisterBurtGeneralSuperintendentNuclearGenerationPAB:pwEnclosure IIJ 212220IS231817161514PORTF12lltIewStitchWeld4PlacesE252627928CONSOLIDATEDELECTROMATICRELIEFVALVE6"-TYPE1525-VXEffectedParts¹4ValveDisc.¹6DiscRetainer¹7LockRetainerPlate¹8LockingScrewWhennormallyclosed,steampressureisequalinChambers"A","B"and"C".Disc4isheldtoseatbygreaterforcein"C"over"B"(differenceinprojectedareas)andspring.Valveoperateswhenpressurein"C"isdecreasedbyopeningofpilotvalve.Highertotalforcein"B"thenpushesDisc4awayfromseatallowingsteamtodischarge.
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