ML18041A184

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Forwards Description of Revised Design for Direct Torus Vent Sys,Per Util Safety Enhancement Program.Design Described Does Not Require Any Change to Tech Specs & Installation Can Begin W/O Prior NRC Approval
ML18041A184
Person / Time
Site: Pilgrim
Issue date: 08/18/1988
From: BIRD R G
BOSTON EDISON CO.
To:
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
BECO-88-126, NUDOCS 8808240277
Download: ML18041A184 (24)


Text

Enclosurelpiigrim"riclearPowerStationRockyHillRoaoriirnc!r.Vassacnvsetts02360RalphG.BirdSe~orviceliesoe"'.-4u<<-earU.S.NuclearRegulatoryCommissionDocumentControlDeskWashington,DC20555BECo88-126Augustk8,1988LicenseOPR-35Docket50-293REVISEDINFORHATIONREGARDINGPILGRIMSTATIONAFTYNHANHNTPRRAH

DearSir:

EnclosedisadescriptionofareviseddesignfortheDirectTorusVentSystem(OTVS)thatwasdescribedinthe"ReportonP1lgrimStationSafetyEnhancements"datedJuly1,1987andtransmittedtotheNRCwithMr.Bird'letter(BECo87-ill)toMr.VargadatedJuly8,1987.Thisrevisionsupersedesin1tsentiretytheSection3.21ncludedintheJulyl,1987report.OnMarch7,1988BostonEdisonCompany(BECo)personnelmetwithOr.Hurley,Hr.Russell,andOr.Thadaniandprov1dedatourofSEPmodif1cationsandaninformalpresentationofthequantificationofcompetingr1sksassociatedwithventingthecontainmentandconclus1onsdrawnfromtheseresults.Th1spresentationprovidedBECotheopportunitytorespondtoquest1onsposedunderItem1Section3,2-"Installat1onofA01rectTorusVentSystem(OTVS)"inHr.Varga'slettertoHr.81rdofAugust2l,1987"InitialAssessmentofPilgrimSafetyEnhancementProgram".ThematerialpresentedwasmadeavailabletotheresidentinspectorandwasincludedasAttachmentIIinNRCInspectionReport488-12,datedMay31,1988.AsyouareawarefromplantinspectionswehaveinstalledtheDTVSp1pingandport1onsofrelatedcontrolwiring.Currently.theDTVSisisolatedfromtheStandbyGasTreatmentSystem(SBGTS)bybl1ndflangesinstalledinplaceofValveAO-5025andtheDTVSrupturedisk.ThisconfigurationwasinspectedbyNRR1ntheperformanceofatechnicalreviewwhichfocusedonSystem,Hechan1calDesignandStructuralDes1gnissues.ThereviewtookplaceonHarch2-3,1988asdocumentedinNRCInspectionReport488-07,datedHay6,l988anddeterminedtheinstallationconfigurat1ontobeacceptable.WenowplantoremovetheseblindflangesandproceedwithinstallationofValveAO-5025andtheDTVSrupturedisk.Weconcludethevalveandrupturediskprov1deequivalentphysicalisolationoftheDTVSp1pingfromtheSBGTSandappropriatelyensuretheoperationalintegrityoftheSBGTSunderdesignbasisaccidentconditions.Followingcompletionofthiswork,wewillperformalocalleakratetesttoverifythatValveAO-5025isacceptablyleaktightusingthesamemethodpreviouslyutilizedintestingthebl1ndflange.Wealsoplantocompleteallremain1ngelectricalworkontheOTVS1naccordancewith=----~h~evi.seddesign.jvppJ,;,"itv rIir'll>>

BOSTONFOISONPANYAugust1&,1988U.S.NuclearRegulatoryCommissionPage2Qnthebas1softherevisedSection3.2,weconcludethattheDTVSdesignasdescribed1ntheenclosuredoesnotrequireanychangetotheTechr.'.calSpecificationsandthatwecanproceedwithinstallationwithoutpriorNRCapproval.PleasefeelfreetocontactmeorMr.3.E.Howard,ofmystaffat(617)849-89001fyouhaveanyquestionspertainingtothedesigndeta11softheDTVS.

Attachment:

Section3.2Rev1s1on1"InstallationOfADirectTorusVentSystem(DTVS)"3EH/amm/2282CC:Hr.0.HcOonald,Pro)ectHanager01visionofReactorPro]ectsI/IIOfficeofNuclearReactorRegulationU.S.NuclearRegulatoryCommiss1onHa11Stat1onPl-137Washington,D.C.20555U.S.NuclearRegulatoryCommiss1onRegionI475AllendaleRoadKingofPrussia,PA19406SeniorNRCResidentInspectorPilgrimNuclearPowerStat1on I4~4 AttachmenttoBECoLetter88-126Section3.2Revision1"Installat)onOfADirectTorusVentSystem(OTVS)"page"14,15,16,17,18,19,19A,198 IPI4$)gt+I 32NTATNFARTTR3.2.13,2.2ivfhnThisdesignchangeprovidestheabilityfordirectventingofthetorustothemainstack.ContainmentventingisonecoredamagepreventionstrategyutilizedtntheBHROwnersGroupEmergencyProcedureGuidelines(EPGs}aspreviouslyapprovedbytheNRCandfsrequiredinplant-specificEmergencyOperatingProcedures(EOPs}.Thetorusventlineconnectingthetorustothemainstackwf11provideanalternateventpathforimplementingEOPrequirementsandrepresentsasignificantimprovementrelativetoexlstlngplantventcapability.For56psisaturatedsteamconditionslnthetorus,apporoximately1'ldecayheatcanbevented.nhnThisdesignchange(Figure3.2-1)providesadirectventpathfromthetorustothemainstackbypassingtheStandbyGasTreatmentSystem(SBGTS).Thebypasslsan8"linewhoseupstreamendlsconnectedtothepipebetweenprimarycontainmentisolationvalvesAO-5042A5B.Thedownstreamendofthebypassisconnectedtothe20"mainstacklinedownstreamofSBGTSvalvesAON-108andAON-112.An8"butterflyvalve(A0-5025),whichcanberemotelyoperated'romthemaincontrolroom,lsaddeddownstreamof8"valveAO-50428.ThisvalveactsastheprimarycontainmentoutboardisolationvalveforthedirecttorusventlineandwillconformtoNRCrequirementsforsealedclosedisolationvalvesasdefinedinNUREG0800SRP6.2.4.ThenewpipeisASMEIIIClass2uptoandinclusiveofvalveAO-5025.TestconnectionsareprovidedupstreamanddownstreamofA0-5025.ThedesignchangereplacestheexlstlngACsolenoidvalveforAO-5042BwfthaDCsolenoidvalve(poweredfromessential125voltDC)toensureoperabilitywithoutdependenceonACpower.Thenewisolationvalve,AO-5025,lsalsoprovidedwithaDCsolenoidpoweredfromtheredundant125voltDCsource.Bothofthesevalvesarenormallyclosedandfallclosedonlossofelectricalandpneumaticpower.OneinchnitrogenlinesareaddedtoprovidenitrogentovalvesAO-5042BandAO-5025.NewvalveAO-5025willbecontrolledbyaremotemanualkey-lockedcontrolswitch.Duringnormaloperation,powertotheAO-5025DCsolenoidwillalsobedisabledbyremovaloffuseslnthewlrlngtothesolenoidvalve.ThissatisfiesNUREG0800SRP6.2.4,ContainmentIsolationSystemacceptancecriteriaforasealedclosedbarrier.AnadditionalfusewillbeinstalledandremaininplacetopowervalvestatusindicationforAO-5025lnthemaincontrolroom.-14-Rev.1(7/25/88)

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NUREG0800,SRP6.2.4,ItemII.6.Fallowstheuseofsealedclosedbarriersinplaceofautomatic1solationvalves.Sealedclosedbarriersincludebl1ndflangesandsealedclosed1solationvalveswhichmaybeclosedremote-manualvalves.SRP6.2.4callsforadministrativecontroltoassurethatsealedclosed1solat1onvalvescannotbe1nadvertentlyopened.This1ncludesmechanicaldevicestosealor'iockthevalveclosed,ortopreventpowerfrombeingsuppliedtothevalveoperator.ConsistentwithSRP6.2.4,valveAO-5025willbeasealedclosedremotemanualvalveunderadministrativecontroltoassurethatitcannotbeinadvertentlyopened.Administrat1vecontrolwillbemaintainedbyakey-lockedremotemanualcontrolswitchandafuseremovedtopreventpowerfrombeingsuppliedtothevalveoperator.InaccordancewithNUREG0737,ItemII.E.4.2.7Position6,AO-5025willbesealedclosedandverif1edassuchatleastevery31days.A20"pipewillreplacetheexisting20"d1ameterductbetweenSBGTSvalvesAON-108,AON-112'andtheexisting20"pipetothemainstack.Theexisting20"d1ameterductdownstreamofAO-5042A1sshortenedtoallowfitupofthenewventlinebranchconnection.Arupturediskwillbeincludedinthe8"pip1ngdownstreamofvalveAO-5025.Therupturediskw111provideasecondleakagebarr1er.Therupturediskisdes1gnedtoopenbelowcontainmentdesignpressure,butwillbeintactuptopressuresequaltoorgreaterthanthosewhichcauseanautomat1ccontainment1solationduringanyaccidentconditions.ThetwoPr1maryContainmentIsolationValves(PCIVs)AO-50428andAO-5025areplacedinser1eswiththerupturedisk.Nos1ngleoperator,errorinvalveoperat1oncanactivatetheDTVS.Therupturediskhasarupturepressureabovetheautomaticconta1nmenthighpressuretrippo1nt.Thus,theinboardPCIV(AO-50428)willreceiveanautomatic1solationpr1ortod1skrupture.TheinboardPCIV(AO-5042B)requiresphys1calelectr1cal)umper1nstallationtoopenatpr1maryconta1nmentpressureabovetheautomatich1ghpressuretrippo1nt.ValveAO-5025willbeclosedwheneverprimaryconta1nmentintegrity1srequiredandDCpowertoitssolenoidcontrolvalvewillbedisconnected.Indicationofvalvepositionwillbeprovidedinthemaincontrolroomevenw1ththevalvepowerremoved.Useofthedirecttorusventw1llbeinaccordancew1thapprovedEPGrequirementsandcontrolledbyEOPsinthesamewannerasotherex1stingconta1nmentventpaths.Pr1ortoopeningtheventvalvestheSBGTsystemwillbeshutdownandvalvesAON-108andAON-ll2(theoutletofSBGT)placed1naclosedposition.-15-Rev.l(7/25/88) h~i, 1New8"ventpipe(8"-H88-44),nclud1ngvalveAO-5025issafetyrelated.Ventpip1ngdownstreamofAO-5025,includingS8GTSdischargepipingtomainstack,isalsosafetyrelated.AllsafetyrelatedpipingwillbesupportedasClassI.Nitrogenpiping1snon-safetyrelatedandwillbesupportedasClassII/I.TheinterpretationoftheClassII/Idesignationthroughthisreportisg1venbelow:AllClassIIitemswhichhavethepotentialtodegradetheintegrityofaClassIitemareanalyzed.SuchClassIIitemsdonotrequiredependablemechanicalorelectr1calfunct1onalitydur1ngSSE,onlythatallofthefollowingconditionsprevail:l.TheClassIIitemscreatenomissileswh1chimpactunprotectedClassIitemssafetyfunctions.2.TheClassIIitemdoesnotdeforminawaywhichwoulddegradeaClassIitem.3.IftheClassIIitemfails,thentheClassIitemisprotectedagainstthefullimpactofallm1ss1lesgeneratedbytheassumedfailureofClassII1tems.Allelectricalportionsofthisdes1gnaresafetyrelatedexceptfortheind1catingl1ghtsontheMIMICpanelC904,thetie-instotheannunciator,andinterfacewiththeplantcomputer.1nhnv3.2.3.1m/mnnAfninmnAhThetoruspurgeexhaustline1nboardisolationvalveAO-50428andtheassociated8"pipearethecomponentsoftheCACSaffectedbythedes1gnmodificat1on.Withincorporationofthesub)ectmodification,theCACSwilldependonbothessent1alAC(forvalveAO-5042A)andessent1alOC(forAO-50428)toperform1tspurg1ngfunct1on.Thenew8"torusventlinewillbeconnectedtoexist1ng8"CACSpipingbetweenvalvesAO-5042BandA0-5042A.-16-Rev.1(7/25/88) lk'Igl TheSBGTSfanoutletvalves(AON-108andAON-112>,ductworkfromthesevalvestothe20"lineleadingtothemainstack,andthe20"11neleadingtothemainstackarethecomponentsofthissystemaffectedbytheproposedchange.ValveAON-108isnormallyclosed,fall-open.ValveAON-1121snormallyclosed,fail-closed,andthesevalvesareprovidedwithessent1alOCpo~erandlocalsafetyrelateda1rsupplies.imrmnmPValveAO-5042BisaffectedbythechangefromACtoOCpowerforthesolenoidandbyreplacementoftheex1stingairsupplywithn1trogen.Theadd1tionofcontainmentoutboardisolationvalve(AO-5025)willnotaffectthePCIS.ValveAO-5025actsasthepr1maryconta1nmentoutboard1solationvalveforthedirecttorusventl1neandwillconformtoNRCrequirementsforsealedclosedisolat1onvalvesasdefinedinNUREG0800SRP6.2.4.ffffm/mnnThissystemhasthesafetyfunctionofreducingthepossib111tyofanenergyreleasewithinthepr1marycontainmentfromaHydrogen-Oxygenreactionfollow1ngapostulatedLOCAcombinedw1thdegradedCoreStandbyCoolingSystem.Thissystemfiltersexhaustairfromthereactorbuild1ngandd1schargestheprocessedairtothemainstack.Thesystemf1ltersparticulatesandiod1nesfromtheexhauststreaminordertoreducethelevelofa1rbornecontam1nationreleasedtotheenv1ronsv1athema1nstack.TheSBGTScanalsof1lterexhaustairfromthedrywellandthesuppressionpool.-17-Rev.l(7/25/88) k\QI4~H1~f~1Ir Thissystemprovidestimelyprotectionagainsttheonsetandconsequencesofdesignbasisaccidentsinvolvingthegrossreleaseofradioactivematerialsfromtheprimarycontainmentbyinitiatingautomaticisolationofappropriatepipelineswhichpenetratetheprimarycontainmentwhenevermonitoredvariablesexceedpre-selectedoperationallimits.imninmnmTheprimarycontainmentsystem,incon3unctionwithothersafeguardfeatures,limitsthereleaseoffissionproductslntheeventofapostulateddesignbasisaccidentsothatoffsitedosesdonotexceedtheguidelinevaluesof10CFR100.3,2.3.3P11ffnf3.2.3.4TheimprovementschangetheAO-5042BsolenoidcontrolfromACtoOCenablingittoopen(fromitsnormallyclosedposition)withnodependenceonACpoweravailability.Theexistingairsupplyto-AO-5042Blsbeingreplacedbynitrogen.DuctworkattheoutletoftheSBGTSlsreplacedwithpipeandthenewventlinelsconnectedtothe20"lineattheoutletoftheSBGTS,Additionofanew8"ventlinewithcontainmentisolationvalveAO-5025off.theexistingtorusventlinecouldintroduceaflowpathunderdesignbasiscond>tlonsthatcouldventthecontainmentdirectlytothestackbypassingtheSBGTS.AnanalysisoftheeffectsonthesafetyfunctionsofCACS,SBGTS,PCISandPCSforthelnstallatlonofthedirecttorusventlsdescribedasfollows:ThechangefromACtoOCcontrolandthereplacementsofairwithnitrogenonAO-50428doesnotadverselyaffecttheabilitytoopenAO-50428whenthecontainmentlsbeingpurged,ortoisolateunderaccidentconditions.-18-Rev.1(7/25/88)

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Themodtftcattonstheductworkand20"1incleadingtothemainstackdonotaffectthedesignbasissafetyfunctionofanyofthesafetyrelatedsystems.Dur1ngnormalplantoperattons,theCACSandtheSBGTSdanotusethetorus20"purgeandventlinetoperformthe1rsafetyfunct1ons.Thecontainmentisolat1onvalvesaretntheirnormallyclosedposition,thusmatntatntngprimarycontainmentboundary1ntegrtty.TherearenoadverseaffectsantheprimarycontainmentsystembytheadditionoftheOTVS.ValveAO-5025willconformtoNRCcriteriaforsealedclosedtsolattonvalvesasdefinedtnNURfG0800SRP6.2.4andwillnotaffectdesignbasisaccidents.UseoftheOTVSwillbeinaccordancewtththecontainmentventingprovisionsofEPGsasapprovedbytheNRCandcontrolledbyEOPstnthesamemannerasotherexistingcontainmentventpaths.Theeffectsonthetorusofthenew8"pipingandAO-5025havebeenevaluatedforHarkIprogramloadtngs,usingASHEBPVCSectionIIIcriteria.Theremainingp1ptngincludingtherupturedtskwasevaluatedusingANSIB31.1requ1rements.Our1ngplantstartupandshutdown(non-emergencycondttton)whenthepurgeandventlineis1nuse,valveAO-5025remainsclosed.Inaddition,theruptured1skdownstreamafvalveAO-5025willprovtdeasecondpositivemeansofpreventingleakageandpreventdirectreleaseuptothestackduringconta1nmentpurgeandventatplantstartuparshutdown.Ouringconta1nmenthighpressurecond1ttons,thetorusma1nexhaust11neisautoeattcally1solatedbythePCIS.Thereisnochangetotheexistingprimarycontainment1solattonsystemfunctionforAO-5042AorAO-50428.ThesealedclosedpositionofvalveAO-5025andtheaddtttanalassuranceaddedbytherupturediskdownstreamwillpreventanyinadvertentdischargeupthestackforalldesignbasisaccidentconditions.InstallationoftheOTVSdoesnotadverselyaffectthesafetyfuncttansoftheCACS,SBGTS,PCISortheintegrityofprimarycontainmentoranyothersafetyrelatedsystems.~-19-Rev.1(7/25/88)

~.JI UseoftheDTVSw111naccordancev1ththeconta1nmentvent1ngprov1s1onsofKPGsasapprovedbytheNRCandcontrolledbyKOPs1nthesamemannerasotherex1st1ngconta1nment,ventpaths.TheOTVSprov1desan1mprovedconta1nmentvent1ngcapab111tyfordecayheatremovalwh1chreducespotent1alons1teandoffs1te1mpactsrelativetotheex1st1ngconta1nmentvent1ngcapab111ty.Rev.1(7/25/88)

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e'cv' GenericLetterNo.89-1688-20SUPPLEMENT1Sub'ectDateofIssuanceINSTALLATIONOFAHARDENED09/01/89WETWELLVENT(GENERICLETTER89-16)GENERICLETTER88-20SUPPLEMENTNO.1(INITIATIONOFTHEINDIVIDUALPLANTEXAMINATIONFORSEVEREVULNERABILITIES10CFR50.54(f))08/29/89LISTOFRECENTLYISSUEDGENERICLETTERSEnc1osure2IssuedToALLGEPLANTSALLLICENSEESHOLDINGOPERATINGLICENSESANDCONSTRUCTIONPERMITSFORNUCLEARPOWERREACTORFACILITIES89-15EMERGENCYRESPONSEDATASYSTEMGENERICLETTERNO.89-1508/21/89ALLHOLDERSOFOPERATINGLICENSESORCONSTRUCTIONPERMITSFORNUCLEARPOWERPLANTS89-0789-14CORRECTACCESSIONNUMBERIS8908220423SUPPLEMENT1TOGENERIC08/21/89LETTER89-07,"POWERREACTORSAFEGUARDSCONTINGENCYPLANNINGFORSURFACEVEHICLEBOMBS"LINE-ITEMSTECHNICALSPECIFI-08/21/89CATIONIMPROVEMENT-REMOVALOF3.25LIMITONEXTENDINGSURVEILLANCEINTERVALS(GENERICLETTER89-14)ALLLICENSEESOFOPERATINGPLANTS,APPLICANTSFOROPERATINGLICENSES,ANDHOLDERSOFCONSTRUCTIONPERMITSALLLICENSEESOFOPERATINGPLANTS,APPLICANTSFOROPERATINGLICENSES,ANDHOLDERSOFCONSTRUCTIONPERMITS89-1389-12GENERICLETTER89-13SERVICEWATERSYSTEMSPROBLEMSAFFECTINGSAFETY-RELATEDEQUIPMENTGENERICLETTER89-12:OPERATORLICENSINGEXAMINATIONS7/18/897/6/89LICENSEESTOALLPOWERREACTORSBWRS,PWRS,ANDVENDORSINADDITIONTOGENERALCODESAPPLICABLETOGENERICLETTERSLICENSEESTOALLPOWERREACTORSBWRS,PWRS,ANDVENDORSINADDITIONTOGENERALCODESAPPLICABLETOGENERICLETTERS lt~fgo"