ML17037C144

Nine Mile Point Unit 1 - Letter Reporting That the Nine Mile Point Reactor Was Scrammed from 25 Percent Power on November 20, 1969 and Advising That the Reactor Will Be Brought Critical and the Turbo-Generator Set Placed on the Line on Dece

ML17037C144
Person / Time
Site:	Nine Mile Point
Issue date:	12/06/1969
From:	Burt P A Niagara Mohawk Power Corp
To:	Morris P A US Atomic Energy Commission (AEC)
References
Download: ML17037C144 (4)

Text

l>X>IllKL4 MO><<.-,>~W%~I~I/DOCKETEDUSAECDECB1969~-gREGUlATORY NlLSECTIONDOCKETCLERK'>>o'o>)'Regulatory NineMilePointNuclearStationP.0.Box32.Lycoming, NewYork13093December6,1969NIAGARAMOHAWKPOWERCORPORATION

,i>>(I'W;,

NIAGARA"~MOHAWKFileCy;,UnitedStatesAtomicEnergyCommission DivisionofReactorLicensing Washington, D.C.20545Attention:

Dr.PeterA.Morris,DirectorGentlemen:

OnThursday,'ovember 20,1969,theNineMilePointreactorwasscrammedfrom25percentpower.Thirtycontrolrods,whichwerehookeduptoabrushrecorder, averaged4.17secondsfor90percentinsertion.

Theoriginal90percentinsertion timeforALLrodswas3.00seconds.Duringtheapproximate six-weektimeintervalbetweentheoriginalandNovember20thscrams,eightdriveswerecontinuously monitored forspurious.

aswellasplannedscrams.Theirtimesfor90percentinsertion increased approximately 40percentduringthemonitoring period.DuringtheNovember20thscram,onerodwasoutsidetheTechnical Specification limitof5.3seconds;RodNo.24-23scrammedin5.32seconds.Inasmuchasexcessive rodinsertion timewasexperienced atOysterCreekduetopartially plugged400meshinnerroddrivestrainers andtherateatwhichourtim-ingwasincreasing gavecausetosuspectournextscrammightbeabovetheTechnical Specification limi.tof5secondsaverage,itwasdecidedtochangeoutthestrainers.

Ascreenhavingclearrectangular openingsof10by100milswasinstalled inplaceoftheoriginal400UnitedStatesstandard.mesh.Inthismanner,thedriveisprotected whiledecreasing screenpluggageprobability byanorderofmagnitude ofapproximately 400times.Theworkwascompleted, including drivetiming,onDecember6,1969.Atthislimeallrodshavebeenscramtestedundercoldpressur-izedconditions withanaverage90percentinsertion timeof2.7seconds.IYhenthereactorreachesoperating pressureandtemperature andwithapproximately 5percentbypasssteamtothecondenser, allrodswillbeindividually scramtested.Neshallcontinuetohonorcommitments previously madeofreporting rodswhose90percentinsertion timedonotfallwithintherangeof1.9to3.6seconds,also,iftheaverage'f 129rodsisnotwithintherangeof2.4to3.1seconds.Thesameeightdrivesasbeforewillcontinue'to beconstantly monitored andscramcheckedonceeverytwoweeksshouldascramnotoccurinthatperiod.Inaddition, theywillbesimilarly testedbeforeplannedscramsfrom50percentpower.Feed-waterqualitywillbecontrolled atalltimesandespecially monitored whenimpuri-tiesmightbeadded,suchaswhencuttinginfeedwater strings,newpumps,pipingsystems,andsoon.

'I4,Pe1' UnitedStatesAtomicEnergyCommission Page2December6,1969Thefollowing chemistry surveillance isperformed andwillcontinuetobeinordertoevaluatethecrudintroduced intothereactorwater:l.A24-hourintegrated crudsampleistakenonthefeedwater enteringthereactorandanalyzeddaily.Thissampletapislocatedsothatitsamplesthefeedwater justbeforethereactorregardless offeed-waterpathused.2.Acontinuously recording turbidimeter isinstalled onthereactorfeedwater togiveassi.stanceinevaluating trends.3.Adailygrabsampleforcrudistakenonthereactorwater.4.i&eneitherconductivity ortheturbidimeter indicatethatacon-densatedemineralizer shouldbechanged,theoperating demineralizer outputs'willbeevaluated forbothconductivity andcrudtodeter-minewhichbedorbedsshouldbeswitched.

5.Everyeffortwillbemadetokeepfeedwater crudlevelslowbyfrequentchangingofdemineralizers andbyreduction offlowthroughthedemineralizers wherenecessary.

6.i&ennewpartsofthefeedwater cyclearebeingcutintoservice,everyeffortwillbemadetorecirculate asmuchcondensate backtothecondenser, therebypolishing itthroughthedemineralizers atahigherrate.ItisexpectedthattheNineMilePointreactorwillbebroughtcriticalandtheturbo-generator setplacedonthelineonDecember8,1969.Duringthefollowing week,additional feedwater heaterswillbebroughtintoserviceandpowerraisedtothe50percentlevel.Verytrulyyours,P.AllisterBurtStationSuperintendent mjscc:Mr.M.H.PrattMr.F.J.Schneider Mr.J.N.Ewart,Chairman, SR5,ABoardMr.M.Hildr'eth, A.E.C.Compliance h.~Ih~,~0~