ML17037C350

Nine Mile Point Unit 1 - Letter Authorizing the Return to Operation of Unit 1 in Accordance with Your Documented Program and Subject to Conditions Defined and Enclosing an ACRS Report Dated June 16, 1970

ML17037C350
Person / Time
Site:	Nine Mile Point
Issue date:	06/19/1970
From:	Morris P A US Atomic Energy Commission (AEC)
To:	Pratt M H Niagara Mohawk Power Corp
References
Download: ML17037C350 (12)

Text

0JUN3,91970DocketMo.50-220Attention:le.KnotH.PrattVicePresidentandExecutiveEngineerhEIIyletterdatedMarch13,1970,requestedappropriatexcpoxtimgofyourxcpairplansandthcsignificantresultsofyourinvestigationandevaluationofthcfurnace-sensitizedatcinleassteelsafeendspriortqtherezmptionofh"'Preactoroperations.Youhavesub>>mittedthisinformationalongwithyourplaneforfuturesurveillanceandtha,resumptionofoperationsinthefollowingdocuments:1.ReactorPrimarySystemInvestigationatNineIQ.lcPoint.NuclearStation"datedHay1,1970.DISTRIBUTIONDoolyDRR.,Engelken,CO(2)H.Shapar,OGC(2)N.Dube~DRL(5)J.R.Buchanan,ORNLT.WLaughlin,DTXE,W.D.Gilbert,GEDocumentRoomv5ocketFileDRReadingDRLReadingNiagaraMohawkPc~rexCorporationBranchRading300ErieBoulevardWestD.Thompson,DRL'yracuse,NcvYork13202D.J.Skuvholt,DRLR.H.Vollmex,DRLD.L.Ziemann,DRLC.J.DeBevec,,DRLR.M.Diggs,DRLACRS(3)Gentlemen:,F.Schroeder,DRLR.BoydR.DeYoungThislottcrauthoxi"csthereturntooperationoftheNineIiXXePointNuclearStation(KP)inaccordancewithyourdocumentedpxogxauforrestorationtoserviceandsubjecttootherconditionswhichaxcdefinedherein.2.'ReactorPximrySystemXnvcstigati.on,atNinaNilePointNuclearStation-ReportNo.2"datedofayll,1970.U3."'PxogramforRestorationtoServiceBasedonReportsofPximaxySystemInvestigation-Nine.HalePointNuclearStation"datedkwyll,1970,Wehavexcvicvedthesereportsincludingtheresultsoftheinves-tigativeprogramandtheevaluationofthemetallurgicalpxoblem,andhaveconcluded.thatyourplansforrepairofthesafeendsandforresumptionofoperationsareacceptableasoctforthinyourreport(Item3above).Inthisregard,Menotethatareinspectionoffurnace=

1,>>I"'~J(.2a~~-..JL'~I"'k>>'i,8>>..>>il.~'i4>>>>>>>>4'I'J">gVg>>L(J~>>Cll~>>>>>>(I/J>><<4,~p3<<IK tNiagaraMohivkPovex'orporation4JUNie,i9Nsensitizedsafeendsvillbemadevithinoneyear.gefurthex'nder-standthateffortsvillbemadetoperformsomeofthissurveillanceduringtheyear,wheneverunscheduledshutdownsprovidetheoppor-tunityforsuchinspection.gerequestthatyouprovideareportoftheresultsofthissurveillanceprogram,includingevaluationoftheirsignificancepromptlyaftex'ompletion>TheAdvt.soryCommitteeonReactorSafeguards(ACRS)revievedthismatteratits122ndmeetingheldJunell-'l3,1970.AcopyofthereportoftheACRS,datedJune16,1970,isenclosed.Initsreport,theACRSmaderecommendatfons,concerning'resumptionandfutux'eopera-tionofthefacilftyiTheseitemsinclude:1,Atleastoneleak-detectionsysteminadditionto'heproposedsumpaccumulatfon"rateanddevpointsystemsshouldbeinstalledvithinafevmonths.2.Assuranceshouldbeprovfdedthat'thebiologicalshieldsuxroundfngthereactorvesselcanwithstandthepxessurethatcouldbedevelopedbylossofintegrftyofasafeendornozzle,orthatfailureoftheshieldvouldhavenointolerableconsequences.Pleaseinformusexpeditiouslyofyourplansregardingimplementationofitem1.Pith,regardtoitem2,verequestthatyousubmitananalysisofshieldintegrityandconsequencesoffailureundertheprescribedconditions.Pleaseadviseusofyourplannedscheduleforsubmittag.Inaddition,aprogramforsurveillanceofthesensitizedmatex'ialovex'helongtermshouldbedeveloped.Sincedeterminationoftheappropriateextentofsuchaprogramvilldependupontheresultsofthesurveillanceperfoxmedduringtheforthcomingyear,verequestthat,inyourreportofthissurveillanceeffort,youincludeyourplansforfurthersurveillanceofthismaterial.Sub)ecttotheaboveconsiderations,vehaveconcludedthatresumptionofoperationsoftheNineMilePointreactorwillnotendangerthehealthand,safetyofthepublic.Sincerely,PeterA,Morris,'ixectorDivisionofReactorlicensingRSReport-6OFFICE>cSURNAME>ArvinE.U......I.eBoeuf..LDATE>FormAL'C-318(Rcv.9-53)16/70.........D.PRL.CDeBe'lEFleu'rDZfemton,Esquire,Lefb.y..@.6/(tt/706/19/70VS.GOVERNNENTI'RtNIINGCfftCE<WOO304598kovhol.Pgchgqedeg.6/g/70~....1}.JL4e6//QQs.../70 k>>)aII"'('1EII'rIfI>>IIt>>II'Itk>>ukI'ltI>>'Ik7Pr~y/k*rI77M~1~\II,JlJt 00ADVISORYCOMMITTEEONREACTORSAFEGUARDSUNITEDSTATESATOMICENERGYCOMMISSIONWASHINGTON,D.C.205454CJune16,1970HonorableGlennT.SeaborgChairmanU.STAtomicEnergyCommissionWashington,D.C.20545

Subject:

REPORTONNINEMILEPOINTNUCLEARSTATION

DearDr.Seaborg:

Atits122ndmeeting,June11-13,1970,theAdvisoryCommittee.onReactorSafeguardsreviewedtheprogramproposedbytheNiagaraMohawkPowerCorporationforrestorationtoserviceoftheNineMilePointStationfollowingthediscoveryduringMarch,1970,ofcracksandleakageina"safeend"(stainlesssteelextensionofthereactorvesselnozzle).TheprogramwasalsoconsideredatSubcommitteemeetingsonMay5,1970,andJune1and2,1970.Duringitsreview,theCommitteehadthebenefitofdiscussionswithrepresentativesoftheapplicant,theGeneralElectricCompany,theAECRegulatoryStaff,andtheirconsultants,andofthedocumentslisted.TheCommitteepreviouslyreportedto;youonthispro)ectonApril17;,1969.\Normalproceduresformostreactorpressurevesselshavebeentojointheausteniticstainlesssteelsafeendstothenozzlespriorto,thestressrelievingheattreatment.Thisheattreat-ment'sensitizesthesafeends,whichmakesthesteellessresistanttocertaintypesofcorrosion.Sensitizedausteniticstainlesssteelsinthisconditionhavegivenreasonablysatis-factoryserviceovermanyreactoryearsofoperation.TheapplicantandtheGeneralElectricCompanyhaveconductedanextensiveinvestigationofthecrackinganditscauses,Anindependentstressanalysisoftheas-builtpipinghasrevealedthatstressesinthecrackedsafeend,andoneothersafeend,wereexcessive.Itisbelievedthatthisexcessivestress,possiblyincombinationwithahighconcentrationof

~ebe~

CHon.GlennT.Seaborg'r~,oxygeninthenon-flowingfluidinthepipeconcerned,causedtheintergranularcrackingofthefurnace-sensitizedstainlesssteelsafeend.Both,oftheoverstressedsafeendshavebeenremovedandreplacedwithnewonesmadeofunsensitizedmaterial.Thethermalsleeveshavebeenslottedtoavoidthepossibilityofgasbubblesatthehighpoints.Thepipingsupportshavebeenrearranged,andtheentireprimarysystemre-analyzed,forbothhotandcoldconditions,togiveassurancethatstresseswillremainwithinallowablelimits.Oneothersafeendmadeofsensitizedmaterialhasbeenremovedandexamined,foundnottocontaincracks,andhasbeenreplacedwithanewoneofunsensitizedmaterial.Allothersafeendsmadeofsensitizedmaterialhavebeennon-destructivelytested.Theminordefectsfoundwillbegroundoutbeforethereactorisoperatedagain.Theapplicantstatedthatexpansionsofprimarypipingwillbemeasuredduringahotfunctionaltesttobeconductedpriortorestartingthereactor,tocheckthepipesupportsandtheseismicrestraints.Theapplicanthasproposedanaugmentedsurveillanceprogramforthesensitizedsafeendsremainingintheprimarysystem,',.includingnon-destructivetestingatleastonceayearandre-checkingpipingexpansionsforseveralfullthermalcycles.TheRegulatoryStaffshouldassureitselfthatthedetailsoftheproposedprogramareappropriate.Theapplicantisstudyingimprovedleak-detectionmethods.TheCommitteebelievesthatdetectionandlocationofsmallleaksisanessentialpartofthesurveillanceprogram.Theapplicantshouldexpeditiouslyinstallsuchleak-detectiondevicesasseemlikelytogiveimprovedsensitivityorspeed'I"ofleakdetection.TheCommitteerecommendsthatatleastoneleak-detectionsysteminadditiontotheproposedsumpaccumu-lationrateanddewpointsystemsbeinstalledwithinafewmonthsandwishestobekeptinformedofprogress,inthisregard.

'IV v+8sr+JI1fonorabl(.GlennT.S>>aborgJun(2',1970ThcCnmmitte(.believ>>sthatthcRegulatoryStaffshouldassur>>its(.lf:L'haLthebjologicalshieldsurroundingthereactorv>>ss(1canwithsL'and~th(.pressur>>thaLcouldbedevelopedbylossofintegrityofasafecndornozzle,orthatfailureoftheshieldwouldhavenointolerablecon-sQ(fu('nc>>seTh(,hCi<Sbelievesthat,iiducr>>gardisgiventothe'r(.commendationsaboveand,initspr>>viousreportLoyouofApril17,1969,thereisxeaso>>abl<<.aSsur(mccthattheNin>>HilePointNucl>>arStationcanbeoperiL(.'(1atpowerlev(:lsupto1>38MM(t)withouL'nduerisktothehealth<<ndsafetyof.thepublic.Sincerelyyours,JosephH.liendrieChaix'manRefer>>n'cesl.NiagaraHohawkPowerCorporationInvestigationatNineNilePoiht,2.NiagaraHohawkPowerCorporationInvestigaL'ionatNiiaeHilcPointdaLedHay11,1970.,report,"ReactorPrimarySystemNuclearStation,"datedHay1,1970.report,"ReactorPrimarySystemNuclearStation,ReportNo.2,"I3.'iagnaMohawkPowerCorporationrepox't,"ProgramforRestorationL'oS<<rviceBasedonRepoxtsofPrimarySystemInvestigationNine,NileI'ointNuclearStation,"datedMay11,1970.

WC'PADL04 Hon.GlennT.Seaborg%30~eCommitteebelievesthattheRegulatoryStaffshouldassureelfthatthebiologicalshieldsurroundingthereactorveselcanwithstandthepressurethatcouldbedevelopedbylossfintegrityofasafeendornozzle,orthatfailureofthesPeldwouldhavenointolerableconsequences.TheACRSlievesthat,ifdueregardisgiventotherecommendat'onsaboveandinitspreviousreporttoyouofApril17,19,thereisreasonableassurancethattheNineMilePointNucearStationcanbeoperatedatpowerlevelsupto1538MN(t)withoutunduerisktothehealthandsafetyofthepublic.,Sincerelyyours,JosephM.endrieChairmanReferences1~NiagaraMohawkPowerCorporatioreport,NEDM-10159,-"PreliminaryReport,CoreSprayNzleSafeEnd,NineMilePointPowerStation",datdMarch27,1970'.NiagaraMohawkPowerCorporationrepor,"ReactorPrimarySystemInvestigationatNineMiPointNuclearStation,ReportNo.2",datedMayll,19~3.NiagaraMohawkPowerCorporationreport,"PrgramforRestorationtoServiceBasedonReportsofPrarySystemInvestigation'NineMilePointNuclearStion",datedMayll,1970,

~\f~