ML18041A184

From kanterella
Revision as of 02:05, 29 June 2018 by StriderTol (talk | contribs) (Created page by program invented by StriderTol)
Jump to navigation Jump to search
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

Enclosure lpiigrim"riclearPowerStationRockyHillRoaoriirnc!r.Vassacnvsetts 02360RalphG.BirdSe~orviceliesoe"'.-4u<<-earU.S.NuclearRegulatory Commission DocumentControlDeskWashington, DC20555BECo88-126Augustk8,1988LicenseOPR-35Docket50-293REVISEDINFORHATION REGARDING PILGRIMSTATIONAFTYNHANHNTPRRAH

DearSir:

Enclosedisadescription ofareviseddesignfortheDirectTorusVentSystem(OTVS)thatwasdescribed inthe"ReportonP1lgrimStationSafetyEnhancements" datedJuly1,1987andtransmitted totheNRCwithMr.Bird'letter(BECo87-ill)toMr.VargadatedJuly8,1987.Thisrevisionsupersedes in1tsentiretytheSection3.21ncludedintheJulyl,1987report.OnMarch7,1988BostonEdisonCompany(BECo)personnel metwithOr.Hurley,Hr.Russell,andOr.Thadaniandprov1dedatourofSEPmodif1cations andaninformalpresentation ofthequantification ofcompeting r1sksassociated withventingthecontainment andconclus1ons drawnfromtheseresults.Th1spresentation providedBECotheopportunity torespondtoquest1ons posedunderItem1Section3,2-"Installat1on ofA01rectTorusVentSystem(OTVS)"inHr.Varga'slettertoHr.81rdofAugust2l,1987"InitialAssessment ofPilgrimSafetyEnhancement Program".

Thematerialpresented wasmadeavailable totheresidentinspector andwasincludedasAttachment IIinNRCInspection Report488-12,datedMay31,1988.Asyouareawarefromplantinspections wehaveinstalled theDTVSp1pingandport1onsofrelatedcontrolwiring.Currently.

theDTVSisisolatedfromtheStandbyGasTreatment System(SBGTS)bybl1ndflangesinstalled inplaceofValveAO-5025andtheDTVSrupturedisk.Thisconfiguration wasinspected byNRR1ntheperformance ofatechnical reviewwhichfocusedonSystem,Hechan1cal DesignandStructural Des1gnissues.ThereviewtookplaceonHarch2-3,1988asdocumented inNRCInspection Report488-07,datedHay6,l988anddetermined theinstallation configurat1on tobeacceptable.

Wenowplantoremovetheseblindflangesandproceedwithinstallation ofValveAO-5025andtheDTVSrupturedisk.Weconcludethevalveandrupturediskprov1deequivalent physicalisolation oftheDTVSp1pingfromtheSBGTSandappropriately ensuretheoperational integrity oftheSBGTSunderdesignbasisaccidentconditions.

Following completion ofthiswork,wewillperformalocalleakratetesttoverifythatValveAO-5025isacceptably leaktightusingthesamemethodpreviously utilizedintestingthebl1ndflange.Wealsoplantocompleteallremain1ng electrical workontheOTVS1naccordance with=----~h~evi.sed design.jvppJ,;,"itv rIir'll>>

BOSTONFOISONPANYAugust1&,1988U.S.NuclearRegulatory Commission Page2Qnthebas1softherevisedSection3.2,weconcludethattheDTVSdesignasdescribed 1ntheenclosure doesnotrequireanychangetotheTechr.'.cal Specifications andthatwecanproceedwithinstallation withoutpriorNRCapproval.

PleasefeelfreetocontactmeorMr.3.E.Howard,ofmystaffat(617)849-89001fyouhaveanyquestions pertaining tothedesigndeta11softheDTVS.

Attachment:

Section3.2Rev1s1on1"Installation OfADirectTorusVentSystem(DTVS)"3EH/amm/2282 CC:Hr.0.HcOonald, Pro)ectHanager01visionofReactorPro]ectsI/IIOfficeofNuclearReactorRegulation U.S.NuclearRegulatory Commiss1on Ha11Stat1onPl-137Washington, D.C.20555U.S.NuclearRegulatory Commiss1on RegionI475Allendale RoadKingofPrussia,PA19406SeniorNRCResidentInspector PilgrimNuclearPowerStat1on I4~4 Attachment toBECoLetter88-126Section3.2Revision1"Installat)on OfADirectTorusVentSystem(OTVS)"page"14,15,16,17,18,19,19A,198 IPI4$)gt+I 32NTATNFARTTR3.2.13,2.2ivfhnThisdesignchangeprovidestheabilityfordirectventingofthetorustothemainstack.Containment ventingisonecoredamageprevention strategyutilizedtntheBHROwnersGroupEmergency Procedure Guidelines (EPGs}aspreviously approvedbytheNRCandfsrequiredinplant-specific Emergency Operating Procedures (EOPs}.Thetorusventlineconnecting thetorustothemainstackwf11provideanalternate ventpathforimplementing EOPrequirements andrepresents asignificant improvement relativetoexlstlngplantventcapability.

For56psisaturated steamconditions lnthetorus,apporoximately 1'ldecayheatcanbevented.nhnThisdesignchange(Figure3.2-1)providesadirectventpathfromthetorustothemainstackbypassing theStandbyGasTreatment System(SBGTS).Thebypasslsan8"linewhoseupstreamendlsconnected tothepipebetweenprimarycontainment isolation valvesAO-5042A5B.Thedownstream endofthebypassisconnected tothe20"mainstacklinedownstream ofSBGTSvalvesAON-108andAON-112.An8"butterfly valve(A0-5025),

whichcanberemotelyoperated'rom themaincontrolroom,lsaddeddownstream of8"valveAO-50428.

Thisvalveactsastheprimarycontainment outboardisolation valveforthedirecttorusventlineandwillconformtoNRCrequirements forsealedclosedisolation valvesasdefinedinNUREG0800SRP6.2.4.ThenewpipeisASMEIIIClass2uptoandinclusive ofvalveAO-5025.Testconnections areprovidedupstreamanddownstream ofA0-5025.ThedesignchangereplacestheexlstlngACsolenoidvalveforAO-5042BwfthaDCsolenoidvalve(poweredfromessential 125voltDC)toensureoperability withoutdependence onACpower.Thenewisolation valve,AO-5025,lsalsoprovidedwithaDCsolenoidpoweredfromtheredundant 125voltDCsource.Bothofthesevalvesarenormallyclosedandfallclosedonlossofelectrical andpneumatic power.OneinchnitrogenlinesareaddedtoprovidenitrogentovalvesAO-5042BandAO-5025.NewvalveAO-5025willbecontrolled byaremotemanualkey-locked controlswitch.Duringnormaloperation, powertotheAO-5025DCsolenoidwillalsobedisabledbyremovaloffuseslnthewlrlngtothesolenoidvalve.Thissatisfies NUREG0800SRP6.2.4,Containment Isolation Systemacceptance criteriaforasealedclosedbarrier.Anadditional fusewillbeinstalled andremaininplacetopowervalvestatusindication forAO-5025lnthemaincontrolroom.-14-Rev.1(7/25/88)

CI~ll(

NUREG0800,SRP6.2.4,ItemII.6.Fallowstheuseofsealedclosedbarriersinplaceofautomatic 1solation valves.Sealedclosedbarriersincludebl1ndflangesandsealedclosed1solation valveswhichmaybeclosedremote-manual valves.SRP6.2.4callsforadministrative controltoassurethatsealedclosed1solat1on valvescannotbe1nadvertently opened.This1ncludesmechanical devicestosealor'iockthevalveclosed,ortopreventpowerfrombeingsuppliedtothevalveoperator.

Consistent withSRP6.2.4,valveAO-5025willbeasealedclosedremotemanualvalveunderadministrative controltoassurethatitcannotbeinadvertently opened.Administrat1ve controlwillbemaintained byakey-locked remotemanualcontrolswitchandafuseremovedtopreventpowerfrombeingsuppliedtothevalveoperator.

Inaccordance withNUREG0737,ItemII.E.4.2.7 Position6,AO-5025willbesealedclosedandverif1edassuchatleastevery31days.A20"pipewillreplacetheexisting20"d1ameterductbetweenSBGTSvalvesAON-108,AON-112'and theexisting20"pipetothemainstack.Theexisting20"d1ameterductdownstream ofAO-5042A1sshortened toallowfitupofthenewventlinebranchconnection.

Arupturediskwillbeincludedinthe8"pip1ngdownstream ofvalveAO-5025.Therupturediskw111provideasecondleakagebarr1er.Therupturediskisdes1gnedtoopenbelowcontainment designpressure, butwillbeintactuptopressures equaltoorgreaterthanthosewhichcauseanautomat1c containment 1solation duringanyaccidentconditions.

ThetwoPr1maryContainment Isolation Valves(PCIVs)AO-50428andAO-5025areplacedinser1eswiththerupturedisk.Nos1ngleoperator, errorinvalveoperat1on canactivatetheDTVS.Therupturediskhasarupturepressureabovetheautomatic conta1nment highpressuretrippo1nt.Thus,theinboardPCIV(AO-50428) willreceiveanautomatic 1solation pr1ortod1skrupture.TheinboardPCIV(AO-5042B) requiresphys1calelectr1cal

)umper1nstallation toopenatpr1maryconta1nment pressureabovetheautomatic h1ghpressuretrippo1nt.ValveAO-5025willbeclosedwheneverprimaryconta1nment integrity 1srequiredandDCpowertoitssolenoidcontrolvalvewillbedisconnected.

Indication ofvalvepositionwillbeprovidedinthemaincontrolroomevenw1ththevalvepowerremoved.Useofthedirecttorusventw1llbeinaccordance w1thapprovedEPGrequirements andcontrolled byEOPsinthesamewannerasotherex1stingconta1nment ventpaths.Pr1ortoopeningtheventvalvestheSBGTsystemwillbeshutdownandvalvesAON-108andAON-ll2(theoutletofSBGT)placed1naclosedposition. Rev.l(7/25/88) h~i, 1New8"ventpipe(8"-H88-44),

nclud1ngvalveAO-5025issafetyrelated.Ventpip1ngdownstream ofAO-5025,including S8GTSdischarge pipingtomainstack,isalsosafetyrelated.Allsafetyrelatedpipingwillbesupported asClassI.Nitrogenpiping1snon-safety relatedandwillbesupported asClassII/I.Theinterpretation oftheClassII/Idesignation throughthisreportisg1venbelow:AllClassIIitemswhichhavethepotential todegradetheintegrity ofaClassIitemareanalyzed.

SuchClassIIitemsdonotrequiredependable mechanical orelectr1cal funct1onality dur1ngSSE,onlythatallofthefollowing conditions prevail:l.TheClassIIitemscreatenomissileswh1chimpactunprotected ClassIitemssafetyfunctions.

2.TheClassIIitemdoesnotdeforminawaywhichwoulddegradeaClassIitem.3.IftheClassIIitemfails,thentheClassIitemisprotected againstthefullimpactofallm1ss1lesgenerated bytheassumedfailureofClassII1tems.Allelectrical portionsofthisdes1gnaresafetyrelatedexceptfortheind1cating l1ghtsontheMIMICpanelC904,thetie-instotheannunciator, andinterface withtheplantcomputer.

1nhnv3.2.3.1m/mnnAfninmnAhThetoruspurgeexhaustline1nboardisolation valveAO-50428andtheassociated 8"pipearethecomponents oftheCACSaffectedbythedes1gnmodificat1on.

Withincorporation ofthesub)ectmodification, theCACSwilldependonbothessent1al AC(forvalveAO-5042A) andessent1al OC(forAO-50428) toperform1tspurg1ngfunct1on.

Thenew8"torusventlinewillbeconnected toexist1ng8"CACSpipingbetweenvalvesAO-5042BandA0-5042A. Rev.1(7/25/88) lk'Igl TheSBGTSfanoutletvalves(AON-108andAON-112>,

ductworkfromthesevalvestothe20"lineleadingtothemainstack,andthe20"11neleadingtothemainstackarethecomponents ofthissystemaffectedbytheproposedchange.ValveAON-108isnormallyclosed,fall-open.

ValveAON-1121snormallyclosed,fail-closed, andthesevalvesareprovidedwithessent1al OCpo~erandlocalsafetyrelateda1rsupplies.

imrmnmPValveAO-5042BisaffectedbythechangefromACtoOCpowerforthesolenoidandbyreplacement oftheex1stingairsupplywithn1trogen.

Theadd1tionofcontainment outboardisolation valve(AO-5025) willnotaffectthePCIS.ValveAO-5025actsasthepr1maryconta1nment outboard1solation valveforthedirecttorusventl1neandwillconformtoNRCrequirements forsealedclosedisolat1on valvesasdefinedinNUREG0800SRP6.2.4.ffffm/mnnThissystemhasthesafetyfunctionofreducingthepossib111ty ofanenergyreleasewithinthepr1marycontainment fromaHydrogen-Oxygen reactionfollow1ng apostulated LOCAcombinedw1thdegradedCoreStandbyCoolingSystem.Thissystemfiltersexhaustairfromthereactorbuild1ngandd1scharges theprocessed airtothemainstack.Thesystemf1ltersparticulates andiod1nesfromtheexhauststreaminordertoreducethelevelofa1rbornecontam1nation releasedtotheenv1ronsv1athema1nstack.TheSBGTScanalsof1lterexhaustairfromthedrywellandthesuppression pool.-17-Rev.l(7/25/88) k\QI4~H1~f~1Ir Thissystemprovidestimelyprotection againsttheonsetandconsequences ofdesignbasisaccidents involving thegrossreleaseofradioactive materials fromtheprimarycontainment byinitiating automatic isolation ofappropriate pipelines whichpenetrate theprimarycontainment whenevermonitored variables exceedpre-selected operational limits.imninmnmTheprimarycontainment system,incon3unction withothersafeguard

features, limitsthereleaseoffissionproductslntheeventofapostulated designbasisaccidentsothatoffsitedosesdonotexceedtheguideline valuesof10CFR100.3,2.3.3P11ffnf3.2.3.4Theimprovements changetheAO-5042BsolenoidcontrolfromACtoOCenablingittoopen(fromitsnormallyclosedposition) withnodependence onACpoweravailability.

Theexistingairsupplyto-AO-5042B lsbeingreplacedbynitrogen.

DuctworkattheoutletoftheSBGTSlsreplacedwithpipeandthenewventlinelsconnected tothe20"lineattheoutletoftheSBGTS,Additionofanew8"ventlinewithcontainment isolation valveAO-5025off.theexistingtorusventlinecouldintroduce aflowpathunderdesignbasiscond>tlons thatcouldventthecontainment directlytothestackbypassing theSBGTS.Ananalysisoftheeffectsonthesafetyfunctions ofCACS,SBGTS,PCISandPCSforthelnstallatlon ofthedirecttorusventlsdescribed asfollows:ThechangefromACtoOCcontrolandthereplacements ofairwithnitrogenonAO-50428doesnotadversely affecttheabilitytoopenAO-50428whenthecontainment lsbeingpurged,ortoisolateunderaccidentconditions. Rev.1(7/25/88)

JI1't'ff%'LcIr,rSh.~lt~

Themodtftcattons theductworkand20"1incleadingtothemainstackdonotaffectthedesignbasissafetyfunctionofanyofthesafetyrelatedsystems.Dur1ngnormalplantoperattons, theCACSandtheSBGTSdanotusethetorus20"purgeandventlinetoperformthe1rsafetyfunct1ons.

Thecontainment isolat1on valvesaretntheirnormallyclosedposition, thusmatntatntng primarycontainment boundary1ntegrtty.

Therearenoadverseaffectsantheprimarycontainment systembytheadditionoftheOTVS.ValveAO-5025willconformtoNRCcriteriaforsealedclosedtsolatton valvesasdefinedtnNURfG0800SRP6.2.4andwillnotaffectdesignbasisaccidents.

UseoftheOTVSwillbeinaccordance wtththecontainment ventingprovisions ofEPGsasapprovedbytheNRCandcontrolled byEOPstnthesamemannerasotherexistingcontainment ventpaths.Theeffectsonthetorusofthenew8"pipingandAO-5025havebeenevaluated forHarkIprogramloadtngs, usingASHEBPVCSectionIIIcriteria.

Theremaining p1ptngincluding therupturedtskwasevaluated usingANSIB31.1requ1rements.

Our1ngplantstartupandshutdown(non-emergency condttton) whenthepurgeandventlineis1nuse,valveAO-5025remainsclosed.Inaddition, theruptured1skdownstream afvalveAO-5025willprovtdeasecondpositivemeansofpreventing leakageandpreventdirectreleaseuptothestackduringconta1nment purgeandventatplantstartuparshutdown.

Ouringconta1nment highpressurecond1ttons, thetorusma1nexhaust11neisautoeattcally 1solatedbythePCIS.Thereisnochangetotheexistingprimarycontainment 1solatton systemfunctionforAO-5042AorAO-50428.

ThesealedclosedpositionofvalveAO-5025andtheaddtttanal assurance addedbytherupturediskdownstream willpreventanyinadvertent discharge upthestackforalldesignbasisaccidentconditions.

Installation oftheOTVSdoesnotadversely affectthesafetyfuncttans oftheCACS,SBGTS,PCISortheintegrity ofprimarycontainment oranyothersafetyrelatedsystems.~-19-Rev.1(7/25/88)

~.JI UseoftheDTVSw111naccordance v1ththeconta1nment vent1ngprov1s1ons ofKPGsasapprovedbytheNRCandcontrolled byKOPs1nthesamemannerasotherex1st1ngconta1nment, ventpaths.TheOTVSprov1desan1mprovedconta1nment vent1ngcapab111ty fordecayheatremovalwh1chreducespotent1al ons1teandoffs1te1mpactsrelativetotheex1st1ngconta1nment vent1ngcapab111ty.

Rev.1(7/25/88)

I'tf' IRTQRUvNTSYTMFiGUAE3.2-IREMOTEMANUALSWAUPTUREDISKFDUCTPIP/

e'cv' GenericLetterNo.89-1688-20SUPPLEMENT 1Sub'ectDateofIssuanceINSTALLATION OFAHARDENED09/01/89WETWELLVENT(GENERICLETTER89-16)GENERICLETTER88-20SUPPLEMENT NO.1(INITIATION OFTHEINDIVIDUAL PLANTEXAMINATION FORSEVEREVULNERABILITIES 10CFR50.54(f))

08/29/89LISTOFRECENTLYISSUEDGENERICLETTERSEnc1osure 2IssuedToALLGEPLANTSALLLICENSEES HOLDINGOPERATING LICENSESANDCONSTRUCTION PERMITSFORNUCLEARPOWERREACTORFACILITIES 89-15EMERGENCY RESPONSEDATASYSTEMGENERICLETTERNO.89-1508/21/89ALLHOLDERSOFOPERATING LICENSESORCONSTRUCTION PERMITSFORNUCLEARPOWERPLANTS89-0789-14CORRECTACCESSION NUMBERIS8908220423 SUPPLEMENT 1TOGENERIC08/21/89LETTER89-07,"POWERREACTORSAFEGUARDS CONTINGENCY PLANNINGFORSURFACEVEHICLEBOMBS"LINE-ITEMS TECHNICAL SPECIFI-08/21/89CATIONIMPROVEMENT

-REMOVALOF3.25LIMITONEXTENDING SURVEILLANCE INTERVALS (GENERICLETTER89-14)ALLLICENSEES OFOPERATING PLANTS,APPLICANTS FOROPERATING

LICENSES, ANDHOLDERSOFCONSTRUCTION PERMITSALLLICENSEES OFOPERATING PLANTS,APPLICANTS FOROPERATING
LICENSES, ANDHOLDERSOFCONSTRUCTION PERMITS89-1389-12GENERICLETTER89-13SERVICEWATERSYSTEMSPROBLEMSAFFECTING SAFETY-RELATED EQUIPMENT GENERICLETTER89-12:OPERATORLICENSING EXAMINATIONS 7/18/897/6/89LICENSEES TOALLPOWERREACTORSBWRS,PWRS,ANDVENDORSINADDITIONTOGENERALCODESAPPLICABLE TOGENERICLETTERSLICENSEES TOALLPOWERREACTORSBWRS,PWRS,ANDVENDORSINADDITIONTOGENERALCODESAPPLICABLE TOGENERICLETTERS lt~fgo"