ML17309A821

Provides 180-day Response to GL 95-07, Pressure Locking & Thermal Binding of Safety-Related Power-Operated Gate Valves.

ML17309A821
Person / Time
Site:	Saint Lucie
Issue date:	02/13/1996
From:	BOHLKE W H FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-95-07, GL-95-7, L-96-31, NUDOCS 9602220094
Download: ML17309A821 (63)

Text

CATEGORY1REGULAT(Q INFORMATION DISTRIBUTIONOSTEM (RIDE)ACCESSION NBR:9602220094 DOC.DATE:

96/02/13NOTARIZED:

YESFACIL:50-335 St.LuciePlant,Unit.1,FloridaPower&LightCo.50-389St.LuciePlant,Unit.2,FloridaPower&LightCo.-AUTH.NAMEAUTHORAFFILIATION BOHLKE,W.H.

FloridaPower.&LightCo.RECIP.NAME RECIPIENT AFFILIATION DocumentControlBranch(Document ControlDesk)NPDRY'UBJECT:

Provides180-dayresponsetoGL95-07,"Pressure Locking&ThermalBindingofSafety-Related Power-Operated GateValves."DOCKETI0500033505000389NOTES:DISTRIBUTION CODE:A056DCOPIESRECEIVED:LTR IENCL+SIZE:TTITLE:GenericLtr95-07-PressureLocking&ThermalBindingofSafetyRelaERECIPIENT IDCODE/NAME NRR/DRPE/EATON NORRISFJVlINTERNAL:

ILECENTERO'IlEXTERNAL:

NOACNUDOCSABSTRACTCOPIESLTTRENCL1111111111RECIPIENT IDCODE/NAME PD2-1PDNRR/EMEB/B NRCPDRCOPIESLTTRENCL1111110DENNOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE)CONTACTTHEDOCUMENTCONTROLDESK,ROOMOWFNSD-5(EXT.

415-2083)

TOELIMINATE YOURNAMEFROMDISTRIBUTION LISTSFORDOCUMENTS YOUDON'TNEED!TOTALNUMBEROFCOPIESREQUIRED:

LTTR"8,ENCL,8 FloridaPower&LightCompany,P.O.Box128,FortPierce,FL34954-0128 IFebruary13,1996L-96-3110CFR50.410CFR50.54(f)U.S.NuclearRegulatory Commission Attn:DocumentControlDeskWashington, D.C.20555RE:St.LucieUnits1and2DocketNos.50-335and50-389GenericLetter95-07-180-DaResonseThisletterprovidestheFloridaPowerandLightCompany(FPL)180-dayresponsetoNRCGenericLetter(NRCGL)95-07"Pressure LockingandThermalBindingofSafetyRelatedPowerOperatedGateValves"forSt.LucieUnits1and'.FPLletterL-95-282datedOctober11,1995,statedthatFPLplanstoimplement theactionsproposedinNRCGL95-07andthattherequested information wouldbeprovidedonorbeforeFebruary13,1996.Inaddition, ourresponsestatedthatifourevaluations determined thatmodifications wererequiredandtheywouldnotbecompleted bythatsubmission date,FPLwouldprovideaschedulealongwiththenecessary justification inourFebruary1996submittal.

Inaccordance withthereporting requirements ofNRCGL95-07,Attachment 1tothisletterprovidesasummaryoftheevaluations performed todemonstrate thatpoweroperatedgatevalvesinstalled atSt.LucieUnits1and2willnotbeprevented fromperforming theiractivesafetyfunctions bythephenomena ofpressurelockingorthermalbinding.Attachment 1alsoprovidestheplansandschedules forthecorrective actionsimplemented orplannedtoassurethesusceptible poweroperatedgatevalveswillremaincapableofperforming theirintendedsafetyfunctions.

Attachment 2providesasummaryoftheoperability assessment forthethreeshutdowncoolingsystemvalvesthatremaintobemodifiedandthejustification forourimplementation schedule.

Thecorrective actionsontheremaining threevalvesthatmaybesusceptible topressurelockingarescheduled tobecompleted duringthenextSt.LucieUnit2refueling outage(SL2-10)whichiscurrently scheduled fortheSpringof1997.'ir602220094 960213PDRADQCK05000335' PDRI.,anFPLGroupcompany

~,p>II RE:St.LucieUnits1and2DocketNo.50-335and50-389GenericLetter95-07-180-DaResonseL-96-31Thisresponseisprovidedpursuanttotherequirements ofSection.182aoftheAtomicEnergyActof1954,asamended,and10CFR50.54(f).

Pleasecontactusifthereareanyquestions aboutthissubmittal.

Verytrulyyours,W.H.olkeVicePresident St.LuciePlantWHB/GRMAttachments cc:StewartD.Ebneter,RegionalAdministrator, RegionII,USNRCSeniorResidentInspector, USNRC,St.LuciePlant v

St.LucieUnits1and2DocketNo.50-335and50-389GenericLetter95-07-180-DaResonseSTATEOFFLORIDA))COUNTYOFST.LUCIE)ssW.H.Bohlkebeingfirstdulysworn,deposesandsays:ThatheisVicePresident, St.LuciePlantfortheNuclearDivisionofFloridaPower&LightCompany,theLicenseeherein;Thathehasexecutedtheforegoing document; thatthestatements madeinthisdocumentaretrueandcorrecttothebestofhisknowledge, information andbelief,andthatheisauthorized toexecutethedocumentonbehalfofsaidLicensee.

H.oeSTATEOFFLORIDACOUNTYOFSt.LucieTheforegoing instrument wasacknowledged beforemethisdayof19g~byW.H.Boe,whoispersonall knowntomeandwhodidtakeanoath.k'.I-Ill=4 W%>lNameofNotaryPuicMyCommission expiresCommission No.95'72KARENWEST=".~$+'=,.WCOMMISSION

~CCSS9929EXPIRESAPIII18,1998if'>r'jj,e80NOEOTIERITROYFARIINEURANCE, INO.

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St.LucieUnits1and2~~~DocketNo.50-335and50-389GenericLetter95-07-180-DaResonseATTACHMENT 1ST.LUCIEUNITSj.G.2PRESSURELOCKINGANDTHERMALBINDINGOFPOWEROPERATEDGATEVALVESEVALUATION METHODOLOGY SUMMARY96O222009$

1-1 0

EVALUATION METHODOLOGY SUMMARYTheassessment ofthesusceptibility ofSt.LucieUnits1and2poweroperatedvalves(POVs)topressurelockingandthermalbindingutilizedathreephasemethodconsisting of:2)Initialscreening toeliminate POVsthatobviously donotmeettheconditions conducive topressurelockingand/orthermalbinding.hGatevalveevaluation todetermine thepoweroperatedgatevalvesthatmaybesusceptible topressurelockingand/orthermalbinding.3)Adetailed, valvespecificanalysistodetermine whetherapoweroperatedgatevalveissusceptible topressurelockingand/orthermalbinding.PHASE1INITIALSCREENING CRITERIAThevalveinitialscreening wasathreestepreviewtodetermine whetheraPOVwasavalvetypesusceptible topressurelockingand/orthermalbinding.Thefirststepwaspoweroperatedvalvetypescreening, thesecondstepwaspressurelockingsusceptibility screening, andthethirdstepwasthermalbindingsusceptibility screening.

Theresultsofthevalvescreening processofmotoroperatedvalves(MOV)forpressurelockingand/orthermalbindingaredelineated inTable1forSt.LucieUnit1andTable2forSt.LucieUnit2.Theresultsofthevalvescreening processforotherPOVsforpressurelockingand/orthermalbindingaredelineated inTable3forSt.LucieUnit1andTable4forSt.LucieUnit2.Power0cratedValveTeScreeninCriteriaAllnon-safety relategatevalveshavebeenexcluedwiththeexception ofthosenon-safety-related gatevalvesthatperformasafety-related orquality-related functionasdefinedinplantoperating procedures.

POVswerereviewedtodetermine safetysignificance undertheNRCGL89-10Program.Motoroperatedvalves(MOVs)excludedfromNRCGL89-10Programwereexcludedfromtheevaluation.

Pressurelockingandthermalbindingonlyconcernsgatevalves.Therefore, alloftheremaining valvedesignshavebeenexcludedfromtheevaluation ofthermalbindingandpressurelockingconditions.

Theplantequipment databasewasutilizedtodetermine thevalvetypes.Valvespressurelockorthermally bindwhenopenedfromafullclosedposition.

Therefore, onlygatevalvesthathaveasafety-relatedfunctiontoopenwereevaluated forpressurelockingand/orthermalbinding.1-2 00 PressureLockinScreeninCriteriaAfterallsafety-related power-operate gatevaveswereidentified, thispopulation ofvalveswasthenscreenedbasedonvalvetypeandactivesafetyfunctiontodetermine whethertherewasapotential forpressurelockingorthermalbindingthatcouldpreventthevalvesfromperforming theirintendedsafetyrelatedfunctions.

Pressurelockingcanonlyoccurindoublediscorflexiblewedgegatevalves;therefore solidwedgedesignswerenotevaluated forpressurelocking.Valvetypeswerebasedonareviewofthevalvedrawings.

Pressurelockingiscausedbyfluidgettingintothevalvebonnetandbetweenthediscsofaflexible-wedge ordouble-disc wedge.Thiscouldpreventdiscmovementduetothepressurebeinghigherinthevalvebonnetandbetweenthediscsthaninthevalvebodyandtheincompressibility ofthefluidinthebonnet.Compressible fluidshavetheabilitytooccupyasmallervolumeandallowthedisctomove,whereasincompressible fluidsdonot.Steamsystemscanbesusceptible topressurelockingduetothecondensation ofsteamthatmayoccurinthevalvebonnet.Gatevalveswithdesignfeaturesthatpreventpressurelocking(e.g.,smallholeindisc,reliefvalveonbonnet,etc.)werescreened.

ThermalBindinScreeninCriteriaDouble-disc parallel-seat discvavesarenotsusceptietotermalbinding.Fromareviewofthevalvedrawings, alltheNRCGL89-10gatevalvesatSt.Lucieareeitherflexible-wedge orsolid-wedge designwiththeexception oftheUnit2auxiliary feedwatersteamsupplyisolation valves(MV-08-12 andMV-08-13) whicharedoublediscgatevalves.Thecondition conducive tothermalbindingiswhenawedgegatevalveisclosedwhilethesystemishot,thenthermalbindingcanoccurasthesystemcools.Therefore, thermalbindingwillnotoccurifthegatevalveisclosedatnormalambienttemperatures.

PHASE2GATEVALVEEVALUATION METHODOLOGY Themethodology usedfortheevaluation ofmotoroperatedgatevalvesnotexcludedbyinitialscreening consisted ofapressurelockingevaluation andathermalbindingevaluation.

Thirty-four motoroperatedvalesremainedtobeevaluated duringthisphase.Summaries ofthegateevaluations fortheSt.LucieUnit1MOVsareprovidedinAppendix1A.Summaries ofthegateevaluations fortheSt.LucieUnit2MOVsareprovidedinAppendix1B.PressureLockinEvaluation Methodolo Variousplantoperational sequences couintrouceconitionsconducive topressurelocking.Irrespective ofinitialbonnetcavityfluidpressure(loworhigh)andtemperature, itisclearthatasubsequent temperature increaseofthefluidcouldcauseanincreaseinbonnetcavitypressuredue1-3 tothermalexpansion ofthefluid.Thetemperature increasecanoccurasfluidoneithersideofadischeatsupduringvariousmodesofplantoperation orpossiblechangesinambientairtemperature causedbyplantoperation, leakingpumpsorvalves,orintheeventofahigh-energy linebreak.Inthesesituations, therateoftemperature

increase, whichmayberelatively slowtoveryhigh,controlsthebonnetcavitypressureandvalvesusceptibility topressurelocking.Conversely, abonnetcavityfilledwithhighpressurefluid,suchasleakagefromthereactorcoolantsystem,becomesapressurelockingcandidate shouldaloss-of-coolant accident(LOCA)orothertransient causepipelinedepressurization.

Basedupontheabove,theevaluation forpotential susceptibility ofaPOVtopressurelockingconsistsoftwoquestions:

2)Canthebonnetbepressurized duetoaPacrossthevalveandsubsequently, thevalvebodyisdepressurized?

Canthebonnetbefilledwithfluidwithasubsequent temperature increaseofthefluidwhichcausesanincreaseinbonnetcavitypressureduetothermalexpansion?

Apositiveresponsetoeitherofthesequestions indicates thatavalvemaybesusceptible topressurelockingandfurtheranalysisisrequired.

ThermalBindinEvaluation Methodolo Theevaluation forpotentxasusceptiiityofapoweroperatedgatevalvetothermalbindingconsistsofonequestion:

Canthevalvebeclosedwhilehotandrequiredtoopenwhenatalowertemperature?

Apositiveresponsetothisquestionindicates thatagatevalvemaybesusceptible tothermalbindingandfurtheranalysisisrequired.

PHASE3VALVESPECIFICANALYSISAdetailed, valvespecificanalysiswasperformed onMOVsthatwerenotexcludedbyeithertheinitialvalvescreening orgatevalveevaluation processes.

Ninemotoroperatedvalveswereidentified aspotentially susceptible topressurelockingand/orthermalbindingandwereevaluated inthisphase.Sixvalvesweremodifiedasdescribed below.ThreevalvesonUnit2remaintobemodified; thebasisfortheircontinued operability isdescribed inAttachment 2.OnSt.LucieUnit1,theshutdowncooling(SDC)systemisolation valves(V-3480,V-3481,V-3651,andV-3652),whichisolatethereactorcoolantsystem(RCS)hotlegsfromtheSDCsystem,are1-4 susceptible onlytopressurelocking.Nopoweroperatedvalveswereidentified asbeingsusceptible tothermalbindingonUnitl.Acalculation wasperformed to'determine thethrustrequiredtoopenthesevalvesassumingthebonnetbecomespressurelockedat2235psig.Asaresult,theactuatorgearratiowaschangedduringtheFall1994St.LucieUnit1refueling outage(SLl-13).

Themodification increased theactuatorcapability sufficiently toovercometheworstcasepressurelockingscenario.

Therefore, pressurelockingisnolongeraconcernfortheUnit1valves(V-3480,V-3481,V-3651,andV-3652).OnSt.LucieUnit2,theSDCisolation valves(V-3480,V-3481,V-3651,andV-3652),whichisolatetheRCShotlegsfromtheSDCsystem,andtheSDCsuctioncross-tie valve(V-3545),

aresusceptible onlytopressurelocking.,Nopoweroperatedvalveswereidentified asbeingsusceptible tothermalbinding.Thecorrective actionfortheSt.LucieUnit2gatevalves,V-3481andV-3545,wasimplemented duringtheFall1995Unit2refueling outage(SL2-9).Aplantmodification wasimplemented toaddanequalization holeinthehighpressuresidediscofV-3481andasecondmodification wasimplemented tochangethenormalpositionofV-3545tonormallyopen.Attachment 2ofthisletterprovidesasummaryoftheoperability assessment andtheschedulejustification forSt.LucieUnit2Cycle9fortheremaining threeSDCisolation motor-operated gatevalves,V-3480,V-3651andV-3652.Thecorrective actionsforthesevalveswillbeimplemented duringtheSt.LucieUnit2Cycle10refueling outage(SL2-10)currently scheduled fortheSpringof1997.Themodification toV-3481wasthepilotimplementation oftheplannedcorrective actionsfortheremaining threevalves.Thesafety-related functionoftheseSDCvalvesistoopentoestablish shutdowncoolingfordecayheatremovalfollowing apostulated accident.

Sincethesevalvesarenotrequiredtoopenfor3to4hoursfollowing anaccident, itwasdetermined thatapressurelockingcondition wouldnotexistifadequateseatleakageexistedtoequalizethepressurebetweenthevalvebonnetandthevalvebody.Theknownvalveseatleakagewoulddepressurize thebonnetoverthistimeperiodandpermitthemotoroperatortoopenthevalve.1-5 TABLEj.ST.LUCIEUNITj.PRESSURELOCKINGANDTHERMALBINDINGSCREENING FORMOTOROPERATEDVALVESVALVENO.NRCGLiGATE'AFETY'RESSURE 89-10VALVEFUNCTIONLOCKINGbTOOPEN123THERMALBINDING12v-1403V-1405V-2501V-2504v-2508v-2509V-2514V-2525v-3206V-3207V-3432V-3444V-3452V-3453V-3456V-3457v-3480v-3481V-3614HCV-3615HCV-3616HCV-3617V-3624HCV-3625YESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESNOYESYESYESNOYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESNONONONOYESNOYESNONOYESYESYESYESYESYESYESYESYESYESYESYESNONONONONOYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESNOYESNOYESNOYESNOYESYESYESYESYESYESYESYESYESYESYESYESYESYESNONONONOYESYESYESYESYESYESIfthoansworinanyofthosocolumnsisNO,thenadditional scrooning forsusceptibility toprossurolockingand/orthormalbindingisnotroquirod.

PRESSURELOCKINGSCREENING CRITERIA)

Ifthoanswertoanyofthofollowing Questions isHOthonthevalveisnotsusceptible topressurelockingandfurtherevaluation isnotroquirod.

l.2~3.DoesthoValvehaveaFloxiblo-Wedge orDouble-Disc WodgeDosign2IsthoVolvoinstalled inaprccossmediacontaining incomprossiblo fluidand/orsteam2IsthoValvolackindosignfeaturesthatpreventprossurolocking(o.g.,smallholeindisc,roliofvavoonbcnnot,otc.).2THERHALBINDIHGSCREENIHG CRITERIA:

Ifthoanswertoanyofthofollowing Questions isNO,thenthevalveisnotsusceptible tothormalbindingandfurtherevaluation isnotrequired.

l.2~DoesthoValvehaveaFlexible-Wedge, Solid-Wedgo orSplit-Wodge Design'2CanthoValvoboclosedundertemperature conditions greaterthannormalambientconditions orduotoHOTambientconditions (o.g.,HELBorHSLB/LOCA) 21-6 TABLEj.ST.LUCIEUNITj.PRESSURELOCKINGANDTHERMALBINDINGSCREENING FORNOTOROPERATEDVALVESVALVENO.NRCGLiGATE'AFETY'RESSURE 89-10VALVEFUNCTIONLOCKINGb123THERMALBINDING12HCV-3626HCV-3627v-3634HCV-3635HCV-3636HCV-3637V-3644HCV-3645HCV-3646HCV-3647V-3651v-3652V-3653V-3654.V-3655V-3656V-3659V-3660v-3662v-3663MV-02-1MV-02-2MV-03-2Mv-03-1AYESYESNOYESYESYESNOYESYESYESYESYESNOYESNOYESYESYESYESYESNONOYESYESNONONONONONONONOYESYESYESYESYESYESYESYESNONOYESYESNONONONOYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESIfthsanswerinanyofthesecolumnsisNO,thenadditional screening forsusceptibility topressurelockingand/orthermalbindingisnotrequired.

PRESSURELOCKINGSCREENING CRITERIA)

Iftheanswertoanyofthefollowing Questions isNOthenthevalveisnotsusceptible topressurolockingandfurtherevaluation isnotrequired.

1.2~3.DoesthsValvehavoaFloxiblo-Wedge orDouble-Disc WodgeDosign2IsthoValveinstalled inaprocossmediacontaining incomprossiblo fluidand/orsteam?IsthoValvo~lackindesignfeaturesthatpreventpressurelocking(o.g.,smallholeindisc,relief~vavoonbonnot,otc.).2THERMALBINDINGSCREENING CRITERIA:

Ifthoanswertoanyofthofollowing Questions isNO,thonthovalveisnotsusceptible tothermalbindingandfurtherevaluation isnotrequired.

1.2.DoesthoValvehaveaFlexible-Wedge, Solid-Wedge orSplit-Wsdgo Design2CantheValvebeclosedundortemperature conditions greaterthannormalambientconditions orduetoHOTambientconditions (e.g.,HELBorMSLB/LOCA) 21-7 0eI TABLEj.ST.LUCIEUNITj.PRESSURELOCKINGANDTHERMALBINDINGSCREENING FORMOTOROPERATEDVALVESVALVENO.NRCGL'ATEaSAFETY'RESSURE 89-10VALVEFUNCTIONLOCKINGbTOOPEN123THERMPJBINDINGc12MV-03-1BMV-07-lAMV-07-1BMV-07-2AMV-07-2BMV-08-1AMV-08-1BMV-08-3MV-08-13MV-08-14MV-09-1MV-09-2MV-09-7MV-09-8MV-09-9MV-09-10MV-09-11MV-09-12MV-09-13MV-09-14MV-14-1MV-14-2MV-14-3MV-14-4YESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESNONONONONONONONONONOYESYESYESYESNONONONONONONONONONONONONONOaIfthoansworinanyofthosocolumnsisNO,thonadditional screening forsusceptibility topressurolockingand/orthermalbindingisnotrequired.

PRESSURELOCKINGSCREENING CRITERIAI Iftheanswertoanyofthofollowing Questions isNOthonthovalveisnotsusceptible toprossurolockingandfurtherevaluation isnotrequired.

1.2.3.DossthoValvohaveaFlexible-Wedge orDouble-Disc WedgeDesign?IstheValvoinstalled inaprocessmediacontaining incompressible fluidand/orsteam?IsthoValvolackindosignfeaturosthatpreventpressurelocking(e.g.,smellboloindisc,reliofvavoonbonnet,etc.).TTHERHALBINDINGSCREENING CRITERIA:

Iftheanswertoanyofthefollowing Questions isNO,thenthevalveisnotsusceptible tothermalbindingandfurtherevaluation isnotrequired.

1~2.DoosthoValvehaveaFlexible-Wedge, Solid-Wedge orSplit-Wedge Design?CanthoValvoboclosedundertemperature conditions greaterthannormalaabientconditions orduotoHOTaabiontconditions

{e.g.,HELBorHSLB/LOCA) 21-8 TABLEj.ST.LUCIEUNITj.PRESSURELOCKINGANDTHERMALBINDINGSCREENING FORMOTOROPERATEDVALVESNRCGLiGATEAUSAFETY'ALVF NO.89-10VALVEFUNCTIONTOOPENPRESSURELOCKINGb123THERMALBINDINGc12MV-14-5mr-14-6MV-14-7MV-14-8MV-15-1MV-18-1MV-21-2MV-21-3FCV-25-9YESYESYESYESYESYESYESYESYESNONONONOYESYESNONONONONOIftheanswerinanyofthesecolumnsisHO,thenadditional screening forsusceptibility topressurelockingand/orthermalbindingisnotrequired.

PRESSURELOCKINGSCREENING CRITERIAI Iftheanswertoanyofthefollowing Questions isHOthenthevalveisnotsusceptible topressurelockingandfurtherevaluation isnotrequired.

l.2.3.DoestheValvehaveaI'lexible-Wedge orDouble-Disc WedgeDesign?IstheValveinstalled inaprocessmediacontaining incompressible fluidand/orsteam?IstheValvelacklnc[designfeaturesthatpreventpressurelocking(e.g.,smallholeindisc,relief~vaveonbonnet,etc.).TTHERMALBINDINGSCREENING CRITERIA:

Iftheanswertoanyofthefollowing Questions isNO,thenthevalveisnotsusceptible tothermalbindingandfurtherevaluation isnotrequired.

l.2.DoestheValvehaveaplexible-Wedge, Solid-Wedge orSplit-Wedge Design?CantheValvebeclosedundertemperature conditions greaterthannormalambientconditions orduetoHOTambientconditions (e.g.,HELBorMSLB/LOCA)

I1-9 v'5'Q~~p TABLE2ST.LUCIEUNIT2PRESSURELOCKINGANDTHERMALBINDINGSCREENING FORMOTOROPERATEDVALVESVALVENO.HRCGLa89-10GATEaVALVESAFETYaFUNCTIONTOOPENPRESSURELOCKINGb123THERMALBINDIHGc12V-1476V-1477V-2185V-2501V-2504v-2508V-2509V-2514V-2525v-2553V-2554V-2555V-2598FCV-3301FCV-3306V-3432V-3444V-3456V-3457V-3480V-3481HCV-,3512V-3517V-3523V-3536v-3539YESYESNOYESYESYESYESYESYESYESYESYESNOYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESNONONONONOYESYESYESYESYESYESNOYESNONONOYESYESNOYESYESYESYESNONONOYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYES,YESYESYESYESYESYESYESYESYESYESYESYESNONONONOYESYESYESYESYESIfthoansworinanyofthesecolumnsisHO,thenadditional screening forsusceptibility topressurelockingand/crthermalbindingisnotrequired.

PRESSURELOCKINGSCREENING CRITERIA1 Iitheanswertoanyofthefollowing Questions isNOthonthovalveisnotsusceptible toprossurelockingandfurtherevaluation isnotrequired.

1~2.3.DoestheValvehaveaFloxiblo-Wedge orDouble-Disc WedgeDesign?IstheValveinstalled inaprocossmodiacontaining incomprossible fluidand/orsteam?IsthoValve~lackindosignfeaturosthatprevontprossurelocking(o.g.,smallholeindisc,relief~vavoonbonnet,otc.).TcTHERMALBINDINGSCREENIHG CRITERIA:

Iftheanswertoanyofthefollowing Questions isNO,thonthovalveisnotsusceptible tothermalbindingandfurtherevaluation isnotrequired.

1.2~DoestheValvehaveaFlexible-Wedge, Solid-Wedge orSplit-Wedge Design?CantheValveboclosedundertemporaturo conditions greaterthannormalambiontconditions orduetoHOTambientconditions (o.g.,HELBorMSLB/LOCA)T 1-10 TABLE2ST.LUCIEUNIT2PRESSURELOCKINGANDTHERMALBINDINGSCREENING FORMOTOROPERATEDVALVESVALVENO.HRCOLa89-10GATEaVALVESAFETYaPRESSVRELOCHIHObFUNCTIOH123TOOPENTHERMALBINDIHGc12V-3540V-3545V-3550V-3551v-3614HCV-3615HCV-3616HCV-3617V-3624HCV-3625HCV-3626HCV-3627v-3634HCV-3635HCV-3636HCV-3637V-3644HCV-3645HCV-3646HCV-3647V-3651V-3652V-3654V-3656HCV-3657v-3658YESYESYESYESNOYESYESYESNOYESYESYESNOYESYESYESNOYESYESYESYESYESYESYESYESYESNOYESNONO~NONONONONONONONONONONONOYESYESYESYESNOYESYESYESNONOYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESIftheanswerinanyofthesecolumnsisNO,then.additional screening forsusceptibility toprossurelockingand/orthermalbindingisnotrequired.

PRESSURELOCKINGSCREENING CRITERIA)

Iftheanswertoanyofthofollowing Questions isHOthenthovalveisnotsusceptible toprossurolockingandfurtherevaluation isnotroquirod.

1~2.3.DoestheValvehaveaFlexible-Wodge orDouble-Disc WedgeDesign?IsthsValveinstalled inaprocessmediacontaining incompressible fluidand/orsteam?IstheValvelackindesignfeaturesthatpreventpressurelocking{o.g.,smallholeindisc,reliefvavoonbonnet,stc.)~2THERMALBINDINGSCREENING CRITERIA:

Iftheanswertoanyofthefollowing Questions isNO,thenthevalveisnotsuscoptiblo tothermalbindingandfurtherevaluation isnotrequired.

1.2.DoestheValvehaveaFlexible-Wedge, Solid-Wedge orSplit-Wedge DesignTCantheValvebeclosedundertomperaturo conditions greaterthannormalambientconditions orduetoHOTambientconditions

{o.g.,HELBorMSLB/LOCA)2 1-11 I

TABLE2ST.LUCIEUNIT2PRESSURELOCKINGANDTHERMALBINDINGSCREENING FORMOTOROPERATEDVALVESVALVENO.NRCGLa89-10GATEVALVESAFETYaFVNCTIONTOOPENPRESSVRELOCHIHGb123THERMALBIHDIHGc12V-3659v-3660v-3664v-3665mr-07-1AMV-07-1BMV-07-2AMV-07-2BMV-08-1AMV-08-1BMV-08-3MV-08-12MV-08-13mr-08-14MV-08-15MV-08-16MV-08-17MV-08-18A MV-08-18B MV-08-19A MV-08-19B MV-09-9MV-09-10MV-09-11MV-09-12MV-09-13YESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESNOYESYESYESYESNONONONONONONOYESYESYESYESYESYESNONONONONONONONONONOYESYESYESYESNONONONOYESYESYESYESYESYESYESYESYESYESYESYESYESYESNONOYESYESIfthoanswerinanyofthosocolumnsisNO,thenadditional screening forsusceptibility topressurelockingand/orthermalbindingisnotrequired.

PRESSURELOCKINGSCREENING CRITERIA; Ifthoanswertoanyofthefollowing Questions isNOthenthevalveisnotsusceptible topressurelockingandfurtherevaluation isnotrequired.

l.2.3.DoesthoValvohaveaFlexible-Wedge orDouble-Disc WedgoDesign?IstheValvoinstalled inaprocessmediacontaining incompressible fluidand/orsteam?IsthoValvo~lsckin dosignfeaturesthatprovontpressurelocking(o.g.,smallholoindisc,roliof~vavoonbonnot,otc.).TTHERMALBINDINGSCREENIHG CRITERIA:

Ifthoanswertoanyofthofollowing Questions isNO,thonthovalveisnotsuscoptiblo tothermalbindingandfurtherevaluation isnotroquired.

1.2.DoesthoValvohaveaFlexible-Wedge, Solid-Wedgo orSplit-Wedge Design?CantheValveboclosedundertemperature conditions greaterthannormalambientconditions orduetoHOTambientconditions

{e.g.,HELBorMSLB/LOCA)T 1-12 TABLE2ST.LUCIEUNIT2PRESSURELOCKINGANDTHERMALBINDINGSCREENING FORMOTOROPERATEDVALVESVALVENO.NRCGL'g-IOGATEaVAIVESAFETYaPRESSVRELOCNING"FUNCTION123TOOPENTHERMALBINDIHGc12MV-09-14MV-14-1MV-14-2MV-14-3MV-14-4MV-14-9MV-14-10MV-14-11MV-14-12MV-14-13MV-14-14MV-14-15MV-14-16MV-14-17MV-14-18MV-14-19MV-14-20MV-21-2MV-21-3MV-21-4AMV-21-4BFCV-25-29 FCV-25-32 FCV-25-33 FCV-25-34 NOYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESYESNONONONONONONONONONONONONONONONONONONONONONONONOIftheanswerinanyofthesecolumnsisNO,thenadditional screening forsusceptibility topressurelockingand/orthermalbindingisnotrequired.

PRESSURELOCKINGSCREENING CRITERIAr Iftheanswertoanyofthofollowing Questions isNOthenthovalvoisnotsuscoptiblo topressurelockingandfurtherevaluation isnotrequired.

l.2.3~DoestheValvehaveaFloxiblo-Wodge orDouble-Disc WedgoDesign?IstheValveinstalled inaprocossmediacontaining incompressiblo fluidand/orsteam?IstheValvelackindosignfeaturesthatpreventpressurelocking{e.g.,smallholeindisc,reliefvavoonbonnet,etc.).?THERMALBINDINGSCREEHING CRITERIA:

Ifthoanswortoanyofthofollowing Questions isNO,thenthevalveisnotsusceptible tothermalbindingandfurtherevaluation isnotrequired.

l.2.DoesthoValvehaveaFloxiblo-Wodge, Solid-Wedgo orSplit-Wodgo Dosign?CantheValveboclosedundertemperature conditions qroatorthannormalambientconditions orduetoHOTambientconditions (e.g.,HELBorMSLB/LOCA)?

1-13

TABLE3ST.LUCIEUNITj.PRESSURELOCKINGANDTHERMALBINDINGSCREENING OFPOWEROPERATEDVALVESVALVENO.POV~GATEVALVESAFETY'UNCTIONTOOPENPRESSURELOCKINGa123THERMALBIHDIHG~12V-3459YESNOIftheanswerinanyofthosecolumnsisNO,thenadditional screoning forsusceptibility topressurelockingand/orthormalbindingisnotrequired.

hPRESSURELOCKIHGSCREENING CRITERIA'f theanswertoanyofthofollowing Questions isNOthonthevalveisnotsusceptible topressurelockingandfurtherevaluation isnotroquired.

1.2.3.DoesthoValvohaveaFlexible-Wedge orDouble-Disc WedgeDesign?IstheValveinstalled inaprocossmediacontaining incompressible fluidand/orsteam?IstheValve~lackindosignfoaturesthatprovontprossurolocking(o.g.,smallhaloindisc,relief~vavoonbonnet,otc.).TcTHERMALBINDINGSCREENING CRITERIA:

Iftheanswertoanyofthofollowing Questions 1sHO,thonthovalvoisnotsusceptible tothermalbindingandfurtherevaluation isnotrequired.

1.2.DoesthoValvehavoaFlexible-Wedge, Solid-Wedge orSplit-Wedge Design?CanthoValveboclosedundertemperature conditions greaterthannormalambientconditions orduetoHOTambiontconditions (e.g.,HELBorMSLB/LOCA)T 1-14 TABLE4ST.LUCIEUNIT2PRESSURELOCKINGANDTHEKItALBINDINGSCREENING FORPOWEROPERATEDVALVESVALVENO.FCV-07-1A FCV-07-1B HCV-09-1A HCV-09-1B HCV-09-2A HCV-09-2B POV'ATEVALVEYESYESYESYESYESYESSAFETY'UNCTION TOOPENYESYESNONONONOPRESSURELOCKINGn123NONOTHERMPJBINDING12NONOIfthoanswerinanyofthesecolumnsisNO,thenadditional screening forsusceptibility topressurelockingand/orthormalbindingisnotrequired.

PRESSURELOCKINGSCREENING CRITERIA'f thoanswertoanyofthofollowing Questions isNOthonthovalveisnotsusceptiblo toprossurolockingandfurtherevaluation isnotrequirod.

l.2.3.DoestheValvehaveaFloxiblo-Wodgo orDouble-Disc WedgeDesign2IsthoValveinstalled inaprocossmediacontaining incompressible fluidand/orstoam2IsthoValve~lackindesignfoaturosthatpreventprossurolocking(e.g.,smallholoindisc,relief~vavoonbonnet,etc.).2THERHALBINDINGSCREENING CRITERIA:

Ifthoanswortoanyofthofollowing Questions isNO,thenthevalveisnotsusceptible tothermalbindingandfurtherevaluation isnotrequired.

l.2.DoestheValvehaveaFlexible-Wodge, Solid-Wedge orSplit-Wedge Design2CantheValvebeclosedundertemperature conditions greaterthannormalambientconditions orduetoHOTambientconditions

{e.g.,HELBorHSLB/LOCA)2 1-15

~~St.LucieUnits1and2DocketNo.50-335and50-389GenericLetter95-07-180-DaResonseAPPENDIX1AST.LUCIEUNIT1GATEEVALUATION SUMMARYOFPRESSURELOCKINGANDTHERMALBINDINGFORPOWEROPERATEDGATEVALVES

ST.LUCIEUNIT1PHASE2GATEVALVEEVALUATION SUMMARYV-1403andV-1405"PowerOperatedReliefValve(PORV)BlockValves"Descrition:V-1403andV-1405are2'/,"VelansolidwedgegatevaveswitSMB-00actuators.

Thevalvesarelocatedin,thecontainment

building, outsidethepressurizer cubicle.Themaximumopeningdifferential pressureis2485psid.Duringpoweroperation bothblockvalvesarerequiredtoremainopen.V-1403andV-1405performthesafety-related functiontopassively maintainRCSpressureboundary.

Thequality-related functionofthesevalvesistoisolatethepressurizer intheeventaPORVisstuckopen.Inaddition, thePORVsareutilizedforcontingencies forfunctional recovery:

RCSpressurecontrolsuccesspath5,PORVsandRCSandcoreheatremoval,successpath4,"once-through-cooling".

Bothofthesecontingencies requireverifying thePORVblockvalvesareopen.PressureLockin:Noevaluation isrequiredbecauseV-1403andV-4aresoiwedgegatevalveswhichhavenotbeendemonstrated tobesusceptible topressurelocking.ThermalBindin:DuringaLOCA,ifactionstoisolatetheLOCAcannoteaccomplished, theOperators aredirectedtoclosethePORVsorcloseV-1403orV-1405.Thesevalvescouldbeclosedathightemperature earlyinaLOCAscenariothenlaterberequiredtoopen,aligningaPORVforlowtemperature overpressure protection (LTOP)oronce-through-cooling, aftertheRCShasbeendepressurized andcooleddown.TheLTOPscenarioisconsidered tobetheboundingthermalbindingscenario.

Areviewwasconducted todetermine ifV-1403andV-1405hadeverbeenclosedhot(e.g.,toisolatealeakingPORV)andsubsequently openedtoalignforLTOP.Itwasdetermined thatbothV-1403&V-1405hadbeenusedtoisolatealeakingPORVwhentheunitwasat100%powerandsubsequently successfully openedtoalignforLTOP.Inaddition, subsequent tothisevent,thesevalveswerechangedtocloseonlimitswitch-inlieuoftorqueswitch.Theuseoflimitswitchcontrolintheclosingdirection reducesthevalveseatingloadsandthepotential forthermalbinding.Conclusion:,

V-1403andV-1405arenotsusceptible tothermalgh1bbjdhp1dworstcasethermalbindingscenario, atatimewhenthepotential ofthermalbindingwasgreaterduetotorqueswitchseatingofthevalves,andthevalvesopened.V-1403andV-1405arenotsusceptible topressurelocking.V-2504"Refueling WaterTank(RWT)Isolation Valve"Descrition:Thisvalveisa3"Velanflex-wedge gatevalvewithanSMB-actuator.

Thevalveislocatedinthe2Achargingpumpcubicleatelevation 0'9".Themaximumopeningdifferential pressureis93psid.Thevalveisnormallyclosed.Thesafety-relatedfunctionofV-2504isopentoalignthechargingpumpstotheRWTforanalternate boratedwatersupplyrequiredbyTechnical Specifications.

Thequality-related functionofV-2504istoautomatically openuponreceiptofavolumecontroltank(VCT)lowlowlevelsignaltoaligntheRWTtothechargingpump(s)suction.PressureLockin:Thereisnoseveredepressurization postulated fortepipingsystemupstreamofV-2504ontheorderofaLOCAorahigh-energy-line-break (HELB).Themostseveredepressurization wouldoccurduetolossofRWTlevel.Therefore, pressurelockingduetoupstreamdepressurization isnotcredible.

Inregardstothermalexpansion offluidtrappedinthebonnet,significant temperature changesatthisvalvearenotpostulated duetothelimitation onsolutiontemperature between55'Fand100'F.Duetothephysicallocationofthevalve,V-2504shouldremainclosetoambienttemperatures atalltimesandpressurelockingisnotaconcern.Thermal-Bindin:V-2504isrestricted bytheTechnical Specification limitation ontemperature fortheRWTof55'Fto100'F.Therefore, itispostulated thatV-2504wouldnotbeclosedhot.Therefore, thermalbindingisnotaconcern.Conclusion:

V-2504isnotsusceptible topressurelockingord'.V-2508&V-2509"BoricAcidGravityFeedValves"Descrition:V-2508&V-2509are3"Velanflex-wedge gatevalveswitSMB-actuators.

Thevalvesareloc'atedinthereactorauxiliary building(RAB)insidetheboricacidmakeuptank(BAMT)cubicleatelevation 2'-7'/,".

V-2508&V-2509arelocatedattheoutletofBAMTs.Themaximumopeningdifferential pressureis28psid.Thesafety-related functionofthesevalvesistoopenuponreceiptofasafetyinjection actuation signal(SIAS)toprovideconcentrated boratedwatertothechargingpumps.PressureLockin:Thereisnoseveredepressurization postulated fortepipingsystemupstreamofthesevalvesontheorderofaLOCAorHELB.Themostseveredepressurization wouldoccurduetochangesinboricacidmakeuptanklevel.Therefore, pressurelockingduetoupstreamdepressurization isnotcredible.

Inregardstothermalexpansion offluidtrappedinthebonnet,significant temperature changesatthesevalvesisnotpostulated becauseofthelowtemperatures inthesystem.ThermalBindin:Duetothelowtemperatures inthesystem,termainingisnotconsidered tobecredible.

==

Conclusion:==

V-2508andV-2509arenotsusceptible topressuregggg.

V-2514'Make-upBypasstoChargingPumps"Descrition:V-2514isa3"AnchorDarlingflex-wedge gatevalvewitanSMB-000actuator.

Thevalveislocatedinthereactorauxiliary building(RAB)-0.5elevation.

Themaximumopeningdifferential pressureis146psid.Thevalveisnormallyclosed.Thesafety-related functionofV-2514isopentoalignthechargingpumpstotheboricacidmake-up(BAM)pumpsforanalternate boratedwatersupplyrequiredbyTechnical Specifications.

PressureLockin:Thereisnoseveredepressurization postulated fortepipingsystemupstreamofV-2514ontheorderofaLOCAorHELB.Themostseveredepressurization wouldoccurduetolossBAMTlevelorlossofaBAMpump.Therefore, pressurelockingduetoupstreamdepressurization isnotcredible.

Inregardstothermalexpansion offluidtrappedinthebonnet,significant temperature changesatthisvalvearenotpostulated duetotheflowofBAMTfluidbecauseofthelimitation onsolutiontemperature

>55'Fandenvironmental conditions

<120'F.ThermalBindin:Duetothelimitation onsystemandenvironmental temperatures etween55'Fand120'F,thermalbindingisnotaconcern.Conclusion:

V-2514isnotsusceptible topressurelockingor~'.V-3452,V-3453,V-3456andV-3457"Shutdown CoolingHeatExchanger Isolation Valves"Descrition:Thesevalvesare10"Velanflex-wedge gatevalveswitSMB-actuators.

Thevalvesarelocatedoutsidethecontainment

building, insidetheRAB,inthe1Aand1Bshutdowncoolingheatexchanger roomsatelevation 4'7".V-3452,V-3453,V-3456andV-3457arenormallylockedclosedisolation valvesthatservetoisolatetheSDCheatexchangers (HXs)fromthelowpressuresafetyinjection (LPSI)systemwhentheSDCHXsarenotinuse.Thesafety-related functionforthesevalvesistoopentoallowwarmupandoperation oftheSDCHXs.Themaximumopeningdifferential pressureis207psid.PressureLockin:FornormalSDCsystemwarm-up,forplacingtheSDCsysteminoperation, andrestoration ofSDCHXs,thesevalvesareopenedwithaLPSIpumprunning.Thereisnorapiddepressurization eventupstreamordownstream ofthesevalves(e.g.,duetoalinebreak)thatwouldrequirethesevalvestoopen.Inregardstothermalexpansion offluidtrappedinthebonnet,thesevalvesarerequiredtoopenforwarminguptheSDCsystemandforrestoring theSDCsystemtoservicefollowing isolation oftheSDCHXs.Therefore, thevalveswouldnotbeheatedpriortoopening.Forrestoration oftheSDCHX,duringthetimeframewheretheSDCHXisbypassed, thereisapotential foranincreaseinSDCsystemtemperature.

However,thesevalvesarenotaffectedbythesystemtemperature increases becauseofthe

~Ie physicallocationofthevalverelativetotheSDCHXinlet/outlet linesandtheSDCbypassline.Therefore, thesevalveswillnotheatupafterclosingduetosystemtemperature increases.

ThermalBindin:Themostlimitingscenarioforthesevalvesisuetoaossofcomponent coolingwater(CCW)totheSDCHXs.Forthisevent,thesevalvescouldbeclosedhot(300'F)andrequiredtoopenafterthesystemhascooledduetotherestoration ofCCWorduetoambientconditions.

However,thermalbindingisnotlikelybecauseitisanticipated thattherestoration ofCCWtotheSDCHXswouldbeashortevolution (i.e.,theSt.LucieUnit1Technical Specifications requirecorrective actiontorestoretheSDCloopstooperablewithin1hourorestablish otherappropriate corrective actions)andthebodyandwedgearecomposedofmaterials whichhavecomparable meancoefficients ofthermalexpansion.

Therefore, thermalexpansion differences wouldbesmallandare.withinthecapability oftheactuators.

==

Conclusion:==

V-3452,V-3453,V-3456andV-3457arenotsusceptible topressurelockingand/orthermalbinding.V-34806V-3652"Shutdown CoolingIsolation Valves"Descrition:Thesevalvesare10"Velanflex-wedge gatevalveswitSMB-actuators.

Thevalvesarelocatedinthecontainment

building, insidethesecondary shieldwallatelevation 34'1".V-3480andV-3652aretheinboard(totheRCS)isolation valvesthatisolate1Aand1BtrainsofSDCsystemfromtheRCS.Themaximumopeningdifferential pressureis273psid.Thesafety-related functionforthesevalvesistoopentoaligntheRCStotheSDCsysteminordertocooltheRCSfromhotshutdown(Mode4)tocoldshutdown(Mode5).ThermalBindin:Typically, V-3480andV-3652areclosedunderhotconditions

('F)whenisolating theSDCsystemduringheatupandopenedcold(<120'Fduetothevalvescoolingtoambientconditions).

Inaddition, thesevalvescouldbeisolatedunderhotconditions duetoaninadvertent isolation ofSDCandcoolifleftisolatedforasignificant periodoftime.Undertheseconditions, thermalbindingcouldoccur.However,itisimportant tonotethatthermalbindinghasnotbeenobservedinthesevalveswhenthevalvesareopenedtoaligntheSDCsystemtotheRCSduringaplantcooldown.

==

Conclusion:==

V-3480andV-3652arepotentially susceptible topressurelockingbutnotthermalbinding.Inaddition, thesevalvesmaybesusceptible toanincreaseinbonnetpressures abovemaximumRCSpressureduetoambienttemperature increaseassociated withamainsteamlinebreak(MSLB)insidecontainment andduetosystemheatupeffectsafterthevalvebonnetshavebecomepressurized.

Thesevalvesrequiredaphase3review,thedetailedvalvespecificanalysisdescribed inAttachment 1(seepage1-4),inorderto determine ifsufficient heatinputfromcontainment isavailable toincreasethevalvebonnettemperature.

V-3481&3651"Shutdown CoolingIsolation Valves"Descrition:Thesevalvesare10"Velanflex-wedge gatevalveswxtSMB-actuators.

Thevalvesarelocatedinthecontainment

building, insidethesecondary shieldwallatelevation 36'9"(V-3481)and29'7"(V-3651).

V-3481andV-3651aretheoutboard(totheRCS)isolation valvesthatisolatelAand1BtrainsofSDCsystemfromtheRCS.Themaximumopeningdifferential pressureis273psid.Thesafety-related functionforthesevalvesistoopentoaligntheRCStotheSDCsysteminordertocooltheRCSfromhotshutdown(Mode4)tocoldshutdown(Mode5).ThermalBindin:Typically, V-3481andV-3651areclosedunderhotconxtz.ons'F)whenisolating theSDCsystemduringheatupandopenedcold(<120'F)duetothevalvescoolingtoambientconditions.

Inaddition, thesevalvescouldbeisolatedunderhotconditions duetoaninadvertent isolation ofSDC.Asaresult,thevalvescouldcoolifleftisolatedforasignificant periodoftimeduetothedistanceofthevalvesfromtheRCS.Undertheseconditions, thermalbindingcouldoccur.However,itisimportant tonotethatthermalbindinghasnotbeenobservedinthesevalveswhenthevalvesareopenedtoaligntheSDCsystemtotheRCSduringaplantcooldown.

==

Conclusion:==

V-3481andV-3651arepotentially susceptible topG1'hh11.dd'.h1maybesusceptible toanincreaseinbonnetpressures abovemaximumRCSpressureduetoambienttemperature increaseassociated withamainsteamlinebreak(MSLB)insidecontainment afterthevalvebonnetshavebecomepressurized.

Thesevalvesrequiredaphase3review,thedetailedvalvespecificanalysisdescribed inAttachment 1(seepage1-4),inordertodetermine ifsufficient heatinputfromcontainment isavailable toincreasethevalvebonnettemperature.

V-3662&V-3663"HighPressureSafetyInjection (HPSZ)PumpSuctionValvesFromSDCHXs"DESCRIPTION:

V-3662&V-3663are4"Velanflexwedgegatevalves~.h11dhatelevation 4'6".Themaximumopeningdifferential pressureis223psid.ThesafetyfunctionofthesevalvesistoopentosupplycooledwaterfromtheSDCHXtothesuctionofthehighpressuresafetyinjection (HPSI)pumpsjustpriortoinitiation ofanrecirculation actuation signal(RAS).PressureLockin:Thesevalvesarenotaffectedbytherapidepressurization associated withMSLBorLOCAduetheirlocationintheemergency corecoolingsystem(ECCS).Themostsignificant depressurization wouldbeassociated withthestartingandstoppingofaLPSIpump.However,thesevalvesarestroketestedquarterly whichadequately demonstrates thecapability ofthesevalvestostrokeafterstartingandstoppingaLPSIpump.Inregardstothermalexpansion offluidtrappedinthebonnet,V-3662&V-3663arerequiredtoopenpost-LOCA afterthecontainment spraypumpshavebeeninjecting 55'F-100'FwaterfromtheRWTandpriortoRAS.Therefore, thereisnoheatinputintotheSDCsystem(priortoRAS)whenV-3662andV-3663arerequiredtoopen.ThermalBindin:Itisnotcredibletopostulate athermalbindingconitionforthesevalveswhentheyarerequiredtoopentoperformtheirsafetyfunctionbecausethetemperature oftheSDCsystemisgreaterthanambientonlywhentheSDCHXsarein-service toshutdowntheunit.ThesevalvesarenotcycledduringthetimetheSDCsystemisalignedtotheRCStoshutdowntheunit.Conclusion:

V-36626V-3663arenotsusceptible topressuregd/h1b.1A-7 0

St.LucieUnits1and2DocketNo.50-335and50-389GenericLetter95-07-180-DaResonseAPPENDIX1BST.LUCIEUNIT2GATEEVALUATION SUMMARYOFPRESSURELOCKINGANDTHERMALBINDING'FORPOWEROPERATEDGATEVALVES P

ST.LUCZEUNIT2PHASE2GATEVALVEEVALUATION SUMMARYV-1476andV-1477"PowerOperatedReliefValve(PORV)BlockValves"Descrition:Thesevalvesare3"Westinghouse flex-wedge gatevaveswitSB-00actuators.

Thevalvesarelocatedinthecontainment

building, outsidethepressurizer cubicle.Themaximumopeningdifferential pressureis2485psid.Inaccordance withSt.LucieUnit2TS,duringpoweroperation onlyoneblockvalveispermitted toremainopen,theotherisclosed.V-1476andV-1477performthesafety-related functiontopassively maintainRCSpressureboundary.

Thequality-related functionofthesevalvesistoberemote-manually actuatedtoisolatetheassociated PORVinordertosatisfythe"fail-closed" requirements oftheirrespective PORV.Inaddition, thePORVsareutilizedforcontingencies forfunctional recovery:

theRCSpressurecontrolsuccesspath5,PORVs,andtheRCSandcoreheatremovalsuccesspath4,once-through-cooling.

Bothofthesecontingencies requireverifying thePORVblockvalvesareopen.PressureLockin:InModes1,2and3,thepressurizer levelismax.ntaine sothatthePORVsandsafetyreliefvalves(andV-1476&V-1477)willrelieveonlysteam.Thebonnetcouldbe'comepressurized inasteamsystemandduetoalargeorsmallbreakLOCA,experience rapiddepressurization upstreamofthevalve.However,thecompressibility ofthesteaminthebonnetprecludes thisscenariofromcausingapressurelockedcondition.

Steampressurization ofMOVbonnetsisapressurelockingconcernduetoconfigurations thatpermitcondensate tocollectanddrainintothevalvebonnet(e.g.,verticalpiperuns)withasubsequent temperature increaseofthevalvebonnet."Upright" valveshavenotexperienced pressurelockingduetosteaminthebonnet.V-1476andV-1477areorientedinthe"upright" position.

ThermalBindin:Undernormalconditions, eitherV-1476orV-1477a.scosepriortoheatinguptheRCStoabove325'F.Inaddition, thevalvesaredemonstrated operableatleastonceper92daysbyoperating thevalvethroughonecompletecycleoffulltravel(unlessclosedwithpowerremoved).

Thevalvesarere-opened toalignforLTOPwhenRCStemperature islessthan240'F.Thereisnoevidencethatthermalbindingoccurswiththesevalvesbecausethesevalveshaveperformed thefunctionofopeningtoalignforLTOPatlessthan240'Fafteroperation inModes1,2and3.Inaddition, thesevalveshaveLimitorque typeSBoperators whichhavecompensating springpacksthatabsorbinertialclosingforcesandpreventexcessive wedgingofthediscintotheseat.Theinstallation ofcompensating springpacksonmotoroperators reducesthevalveseatingloadsandthepotential forthermalbinding.Conclusion:

V-1476andV-1477arenotsusceptible topressuregd/h11"g.

V-2504"RWTIsolation Valve"Descrition:Thisvalveisa3"Westinghouse flex-wedge gatevavewitanSB-00actuator.

Thevalveislocatedinthe2Achargingpumpcubicleatelevation 0'9".Themaximumopeningdifferential pressureis29psid.Thevalveisnormallyclosed.Thesafety-related functionofV-2504isopentoalignthechargingpumpstotherefueling watertank(RWT)foranalternate boratedwatersupplyrequiredbyTechnical Specifications.

However,creditisnottakenforremoteoperation ofV-2504becausetheoperatorisnotClass1E.Instead,theassumption isplantoperators willmanuallyopenthevalve.Inaddition, thequality-related functionifV-2504istoautomatically openuponreceiptofaVCTlowlowlevelsignaltoaligntheRWTtothechargingpump(s)suction.PressureLockin:Thereisnoseveredepressurization postulated ortepipingsystemupstreamofV-2504ontheorderofaLOCAorHELB.Themostseveredepressurization wouldoccurduetolossofRWTlevel.Therefore, pressurelockingduetoupstreamdepressurization isnotcredible.

Inregardstothermalexpansion offluidtrappedinthebonnet,significant temperature changesatthisvalvearenotpostulated duetotheflowofRWTfluidbecauseofthelimitation onsolutiontemperature between55'Fand100'F.ThermalBindin:Fluidtemperature inV-2504isrestricted bytheTecnicaSpecification limitation ontemperature fortheRWTof55'Fto100'F.Itispostulated thatV-2504wouldnotbeclosedattemperatures greaterthan100'F;therefore thermalbindingisnotaconcern.Conclusion:

V-2504isnotsusceptible topressurelockingordg.V-2508&V-2509"BoricAcidGravityFeedValves"Descrition:V-2508&V-2509are3"Westinghouse flex-wedge gatevaveswitSB-00actuators.

Thevalvesarelocatedinthereactorauxiliary building(RAB)insidetheboricacidmakeuptank(BAMT)cubicleatelevation 13'-6.5".

V-2508&V-2509arelocatedattheoutletofBAMTs.Themaximumopeningdifferential pressureis16.2psid.Thesafety-related functionofthesevalvesistoopenuponreceiptofaSIAStoprovideconcentrated boratedwatersupplytothechargingpumps.PressureLockin:Thereisnoseveredepressurization postulated ortepipingsystemupstreamofthesevalvesontheorderofaLOCAorHELB.Themostseveredepressurization wouldoccurduetochangesinboricacidmakeuptanklevel.Therefore, pressurelockingduetoupstreamdepressurization isnotcredible.

Inregardstothermalexpansion offluidtrappedinthebonnet,significant temperature changesatthesevalvesisnotpostulated becauseofthelowtemperatures inthesystem.

ThermalBindin:Duetothelowtemperatures inthesystem,thermalindingisnotconsidered tobecredible.

==

Conclusion:==

V-2508andV-2509arenotsusceptible topressureghh.V-2514"BoricAcidMakeupBypasstoChargingPumps"Descrition:V-2514isa3"Westinghouse flex-wedge gatevalvewitanSB-00actuator.

Thevalveislocatedintheboricacidmakeup(BAMT)cubicleatelevation 2'".Themaximumopeningdifferential pressureis132.2psid.Thevalveisnormallyclosed.Thesafety-related functionofV-2514isopentoalignthechargingpumpstotheBAMpumpsforanalternate boratedwatersupplyrequiredbyTechnical Specifications.

PressureLockin:Thereisnoseveredepressurization postulated fortepipingsystemupstreamofV-2514ontheorderofaLOCAorHELB.Themostseveredepressurization wouldoccurduetolossBAMTlevelorlossofaBAMpump.Therefore, pressurelockingduetoupstreamdepressurization isnotcredible.

Inregardstothermalexpansion offluidtrappedinthebonnet,significant temperature changesatthisvalvearenotpostulated duetothelimitation onsolutiontemperature between55'Fand100'F.ThermalBindin:Duetothelimitation onsolutiontemperature etweenFan100'F,thermalbindingisnotaconcern.Conclusion:

V-2514isnotsusceptible topressurelockingord'.V-34566V-3457"Shutdown CoolingHeatExchanger OutletValves"Descrition:Thesevalvesare10"Westinghouse flex-wedge gatevaveswitSB-0actuators.

Thevalvesarelocatedoutsidethecontainment

building, insidetheRAB,inthe2Aand2Bsafeguards rooms.V-3456andV-3457arenormallylockedclosedisolation valvesthatservetoisolatetheSDCheatexchangers fromtheLPSIsystemwhentheSDCHXsarenotinuse.Thesafety-related functionforthesevalvesistoopentoallowwarmupandoperation oftheSDCHXs.Themaximumopeningdifferential pressureis269psid.PressureLockin:FornormalSDCsystemwarm-up(andforplacingteSDCsysteminoperation),

thesevalvesareopenedpriortostartingtheLPSIpumpsandbeforetheSDCsystemisalignedtotheRCS.Thereisnorapiddepressurization eventupstreamordownstream ofthesevalves(e.g.,duetoalinebreak)thatwouldrequirethesevalvestoopen.Forrestoration ofSDCHXsevents,thesevalveswouldbeclosedandreopenedonalossofCCWtoaSDCHX.ThesevalveswouldbereopenedwithaLPSIpumprunning.Therefore, thereisnodepressurization eventpostulated inwhichthevalvesarereliedupontoopen.Inregardstothermal expansion offluidtrappedinthebonnet,V-3456andV-3457arerequiredtoopenforwarminguptheSDCsystemandforrestoring theSDCsystemtoservicefollowing isolation oftheSDCHXs.Forwarmup,thesevalvesareopenedpriortostartingtheassociated LPSIpump.Therefore, thevalveswouldnotbeheatedpriortoopening.Forrestoration oftheSDCHXevent,thephysicallocationofthevalvespreventsthemfrombeingexposedtotemperature increases inthesystem.ThermalBindin:ForalossofCCWtotheSDCHXs,thesevalvescouecosedhotandrequiredtoopenafterthesystemhascooledduetotherestoration ofCCWorduetoambientconditions.

However,forthefollowing reasons,thermalbindingisnotlikely:1)Itisexpectedthattherestoration ofCCWtotheSDCHXswouldbeashortevolution (i.e.,<30minutes)andthesevalveswouldlikelynotexperience significant coolinginthistimeframe;2)V-3456andV-3457arecontrolled inthecloseddirection bypositionlimitswitches(thislimitstheseatingforceofthediscintheseats);3)V-3456andV-3457haveSB-0actuators installed onthem.SBLimitorque operators havecompensating springpacksthatabsorbinertialclosingforcesandpreventexcessive wedgingofthediscintotheseat.Theinstallation ofcompensating springpacksonmotoroperators reducesthevalveseatingloadsandthepotential forthermalbinding;4)Thebodyanddiscareidentical materials.

Therefore, thermalexpansion differences wouldbesmallandarewithinthecapability oftheactuators.

==

Conclusion:==

V-3456andV-3457arenotsusceptible topressuregd/h1b.V-34806V-3652"Shutdown CoolingIsolation Valves"Descrition:Thesevalvesare10"Westinghouse flex-wedge gatevaveswitSMB-1actuators.

Thevalvesarelocatedinthecontainment

building, insidethesecondary shieldwallatelevation 39'0"(V-3480)and30'6"(V-3652),

respectively.

V-3480andV-3652arethein-board(totheRCS)isolation valvesthatisolate2Aand2BtrainsofSDCfromtheRCS.Themaximumopeningdifferential pressureis277psid.Thesafety-related functionforthesevalvesistoopentoaligntheRCStotheSDCsysteminordertocooltheRCSfromhotshutdown(Mode4)tocoldshutdown(Mode5).ThermalBindin:Typically, V-3480andV-3652areclosedunderhotconz.talons('F)whenisolating theSDCsystemduringheatupandopenedcold(<120'F)duetothevalvescoolingtoambientconditions.

Inaddition, thesevalvescouldbeisolatedunderhotconditions duetoaninadvertent isolation ofSDC.Asaresult,thevalvescouldcoolifleftisolatedforasignificant periodoftimeduetothedistanceofthevalvesfromtheRCS.Undertheseconditions, thermalbindingcouldoccur.However,itisimportant tonotethatthermalbindinghasnotbeenobservedinthesevalveswhenthevalvesareopenedtoaligntheSDCsystemtotheRCSduringaplantcooldown.

==

Conclusion:==

V-3480andV-3652arepotentially susceptible topCk'bh1b.dd'.h1maybesusceptible toanincreaseinbonnetpressures abovemaximumRCSpressureduetoambienttemperature increaseassociated withaMSLBinsidecontainment afterthevalveshavebecomepressurized.

Thesevalvesrequiredaphase3review,the'detailed valvespecificanalysisdescribed inAttachment 1(seepage1-4),inordertodetermine ifsufficient heatinputfromcontainment isavailable toincreasethevalvebonnettemperature.

V-3481,V-3651&V-3545"Shutdown CoolingIsolation Valves"Descrition:Thesevalvesare10"Westinghouse flex-wedge gatevaveswitSMB-1actuators.

Thevalvesarelocatedinthecontainment

building, insidethesecondary shieldwallatelevation 39'0"(V-3481),

30'6"(V-3651)and36'3"(V-3545),

respectively.

V-3481andV-3651aretheoutboard(totheRCS)isolation valvesthatisolate2Aand2BtrainsofSDCsystemfromtheRCS.V-3545istheSDCsuctioncross-tie isolation valve.Themaximumopeningdifferential pressureis277psid(V-3481&V-3651)and275psid(V-3545).

Theshutdowncoolingsuctionlinesareconfigured suchthatoneofthetwoisolation valvesineachlineispoweredfromthe2Atrain,whilethesecondisolation valve,ispoweredfromthe2Btrain.Thecross-tie valve(V-3545)ispoweredfromthe480Vmotorcontrolcenter(MCC)2AB,whichcanbealignedtoeitherthe2Aor2Belectrical train.Thisconfiguration wasrequiredtoensurethattheSDCsystemcouldbealignedtotheRCSintheeventofalossofeither2Aor2Btrainpower.Therefore, thesafety-related functionforthesevalvesistoaligntheRCStotheSDCsysteminordertocooltheRCSfromhotshutdown(Mode4)tocoldshutdown(Mode5).ForV-3545,thesafetyfunctionisrequiredasaredundant designfeatureforalossofelectrical power"tooneoftheelectrical trains.ThermalBindin:Typically, V-3481,V-3651andV-3545areclosedunerotconitions(>300'F)whenisolating theSDCsystemduringheatupandopenedcold((120'F)duetothevalvescoolingtoambientconditions.

Inaddition, thesevalvescouldbeisolatedunderhotconditions duetoaninadvertent isolation ofSDC.Asaresult,thevalvescouldcoolifleftisolatedforasignificant periodoftimeduetothedistanceofthevalvesfromtheRCS.Undertheseconditions, thermalbindingcouldoccur.However,itisimportant tonotethatthermalbindinghasnotbeenobservedinthesevalveswhenthevalvesareopenedtoaligntheSDCsystemtotheRCSduringaplantcooldown.

==

Conclusion:==

V-3481,V-3651,andV-3545arepotentially susceptible topressurelockingbutnotthermalbinding.Inaddition, thesevalvesmaybesusceptible toanincreaseinbonnetpressures abovemaximumRCSpressureduetoambienttemperature increaseassociated withaMSLBinsidecontainment afterthevalveshavebecomepressurized.

Thesevalvesrequiredaphase3review,thedetailed IK' valvespecificanalysisdescribed inAttachment 1(seepage1-4),inordertodetermine ifsufficient heatinputfromcontainment isavailable toincreasethevalvebonnettemperature.

V-3517andV-3658"Shutdown CoolingHeatExchanger InletIsolation Valves"-3517d-355511"*'ggl-dggatevalveswithSB-Oactuators.

Thevalvesarelocatedoutsidethecontainment

building, insidethereactorauxiliary

building, inthe2Aand2Bsafeguards roomsatelevations

-7'10"(V-3517)and-2'8'/,"(V-3658).

Thesevalvesarenormallylockedclosedisolation valvesthatservetodisolate theSDCheatexchangers fromtheLPSIsystemwhentheSDCHXsarenotinuse.Thesafety-related functionforthesevalvesistoopentoallowwarmupandoperation oftheSDCHXs.Themaximumopeningdifferential pressureis162psid.PressureLockin:FornormalSDCsystemwarm-upandforplacingteSDCsysteminoperation, thesevalvesareopenedafterstartingtheLPSIpumpsandbeforetheSDCsystemisalignedtotheRCS.Thereisnorapiddepressurization eventupstreamordownstream ofthesevalves(e.g.,duetoalinebreak)thatwouldrequirethesevalvestoopen-.Inregardstothermalexpansion offluidtrappedinthebonnet,V-3517andV-3658arerequiredtoopenforwarminguptheSDCsystem.Forwarmup,thesevalvesareopenedafterstartingtheassociated LPSIpumpandpriortoopeningtheSDCHXflowcontrolvalve.FlowisroutedthroughtheSDCHXuntilthesystemheatsup.Therefore, thevalveswouldnotbeexposedtotemperature increases priortoopening.ThermalBindin:Themostlimitingscenarioisisolation ofV-3517anV-uetore-alignment oftheSafetyInjection systemafterheatup.Inthisscenariothevalvesareclosedafterrecirculating theSDCto150'F.DuringwarmuptoplacetheSDCinservice,thevalveswouldberequiredtoopenatatemperature

<150'F.Thermalbindingisnotlikelybecausethechangeintemperature fromremovaloftheSDCsystemfromservicetowarmingthesystemupisrelatively small,andthebodyanddiscarecomposedofthesamematerial.

Therefore, thermalexpansion differences wouldbesmall.Inaddition, thesevalveshaveoperators whichhavecompensating springpacksthatabsorbinertialclosingforcesandpreventexcessive wedgingofthediscintotheseat.Theinstallation ofcompensating springpacksonmotoroperators reducesthevalveseatingloadsandthepotential forthermalbinding.Conclusion:

V-3517andV-3658arenotsusceptible topressuregd/515.V-36646V-3665"Shutdown CoolingIsolation Valves"Descrition:Thesevalvesare10"Westinghouse flex-wedge gatevaveswa.tSB-0actuators.

Thevalvesarelocatedoutsidethecontainment

building, insidetheRABatelevation 24'7"(V-3664) 00 and25'0"(V-3665),

respectively.

V-3664andV-3665arethecontainment isolation valvesthatisolate2Aand2BtrainsofSDC.Themaximumopeningdifferential pressureis269psid.Thesafety-relatedfunctions forthesevalvesistoprovidecontainment isolation andtoopentoaligntheRCStotheSDCsysteminordertocooltheRCSfromhotshutdown(Mode4)tocoldshutdown(Mode5).PressureLockin:V-3664&V-3665aresubjected toupstreampressurefromtheRCSduringalignment forshutdowncooling.ThisscenarioassumesthatV-3664&V-3665areopenedfollowing theopeningoftheupstreamshutdowncoolingisolation valves.Thereisnorapiddepressurization associated withthisscenario.

However,ifitisassumedthatthereisleakagepastupstreamisolation valvesV-3664&V-3665thelinecouldbepressurized to335psig(theSDCreliefvalvesetpoint).

However,forthedepressurization oftheRCSfrom350psiato275psia(thepermissive setpointforaligningtheRCStoSDC),forMSLBorsmallbreakLOCAscenarios, thedepressurization isnotsignificantly different fromthenormalPlantCooldownscenario.

Therefore, itisreasonable toconcludethatthesevalvesarenotsusceptible topressurelockingbasedthecapability ofthesevalvestoopenforanormalplantshutdown.

Inregardstothermalexpansion offluidtrappedinthebonnet,V-3664andV-3665remainclosedwhentheSDCsystemiswarmed-up.

However,V-3664andV-3665arephysically isolatedfromtheflowpathforSDCwarm-up.ThermalBindin:Thesevalvescouldbeclosedunderhotconditions (i.e.,SDCcoolingisolatedwhiletheRCSisstillhotorinadvertent isolation ofSDC),andthevalvecouldcoolifleftisolatedforasignificant periodoftimeduetothedistanceofthevalvefromtheRCS.Undertheseconditions, thermalbindingcoul'doccur.However,thesevalve'shaveoperators whichhavecompensating springpacksthatabsorbinertialclosingforcesandpreventexcessive wedgingofthediscintotheseat.Theinstallation ofcompensating springpacksonmotoroperators hasbeenidentified asonemethodforpreventing thermalbinding.Therefore, V-3664andV-3665arenotconsidered tobesusceptible tothermalbinding.Conclusion:

V-3664andV-3665arenotsusceptible topressuregh11.MV-08-12&MV-08-13"2CAuxiliary FeedWater(AFW)PumpSteamAdmission Valves"DESCRIPTION:

Thesevalvesare4"Pacificdoublediscgatevalves.1d'y.hdifferential pressureis1015psid.Thesevalvesarenormallyclosedandopenathightemperature (i.e.,operating temperature

=532'F).Thesevalvesopenuponreceiptofanauxiliary feedwateractuation signal(AFAS)andprovideaflowpathfrommainsteamtothe2CAFWpumpturbine.Inaddition, thevalvesmustbecapableofoperating ondemandtoinitiate2CAFWflowtothesteamgenerators toreduceRCStemperature totheentrytemperature forinitiating theSDC.PressureLockin:MV-08-12andMV-08-13couldexperience rapidepressurxzation upstreamofthevalve(e.g.,MSLB,feedwater,line break).However,sincethesevalvesaresteamvalves,thecompressibility ofthesteaminthebonnetprecludes thisscenariofromcausingapressurelockedcondition.

Pressurelockingofsteamvalvesoccursduetoconfigurations thatpermitcondensate tocollectanddrainintothevalvebonnet(e.g.,verticalpiperuns)withasubsequent temperature increaseofthevalvebonnet.MV-08-12andMV-08-13areinstalled inhorizontal piperunswiththeactuators mountedabovethecenterline ofthepipe.Basedupontheconfiguration ofMV-08-12andMV-08-13, itisunlikelythatcondensate wouldcollectintheirbonnets.ThermalBindin:Doublediscgatevalvesarenotconsidered susceptxetothermalbinding.Conclusion:

MV-08-12andMV-08-13arenotsusceptible topressureg1gh.1B-9

St.LucieUnits1and2DocketNo.50-335and50-389GenericLetter95-07-180-DaResonseATTACHMENT 2ST.LUCIEUNIT2SUMMARYOFTHEOPERABILITY ASSESSMENT FORPRESSURELOCKINGOFSHUTDOWNCOOLINGPOWEROPERATEDGATEVALVESV-.3480,V-3651,ANDV-36522-1 EVALUATION AlthoughtheNRCGL95-07doesnotpermitavalvetobeexcludedfromconsideration ofpressurelockingduetolackofoccurrence atthespecificplant,orvalveleakagerate,FPLconsiders thattheactualvalveseatleakageandvalvehistorical performance areacceptable fordetermining valveoperability untilthefinalcorrective measuresareimplemented.

Duringtheevaluation oftheUnit2SDCisolation valves(V-3480,V-3651andV-3652)forthepurposesofdemonstrating operability, theactualvalveseatleakageperformance wasutilized.

TheNRCGLdidnotdiscusstheexclusion ofseatleakagefordetermining valveoperability andthisapproachdoesnotexcludethevalvesfromfurtherconsideration ofpressurelocking.Additionally, apressurelockingeventhasnotbeenidentified forthisWestinghouse valvedesign(1500psiclassflexwedgegate)oneitherSt.Lucieunit,andnonewereidentified inthereviewofNUREG-1275',

Volume9,Supplement 6toNRCGL89-10',NRCIN92-26'rINPOSOER84-074.ValveLeakaeReuiredandSurveillance DataFPLhasconservative ycacuatetatvaveseateaage>.004gpmforV-3480andV-3652,andthatseatleakage>0.011gpmforV-3651wouldreducepressureinthevalvebonnetsandthepipingbetweentheSDCisolation valvestoshutdowncoolingentryconditions

(-250psig)within3hoursfollowing themostlimitingpressurelockingscenario.

ThemostlimitingscenarioforpressurelockingisaMSLBinsidecontainment.

AlargebreakLOCAisnotconsidered limitingbecausethecontainment sumprecirculation wouldprovidefordecayheatremoval,andtheshutdowncoolingisolation valveswouldnotberequired.

AsmallbreakLOCAwouldresultinrapiddepressurization, butwouldnotsignificantly heatupcontainment.

Valveseatleakagesurveillance requirements specified inSt.LucieUnit2Technical Specification

,(TS)4.4.6.2.3 aresatisfied byperforming Administrative Procedure 2-0010125A at>leastonceevery18months.Thesurveillance testisalsorequirediftheunitentersMode5andthetesthasnotbeenperformed inthepreceding 9months.Thetestisperformed withadifferential pressuregreaterthan200psidacrossthevalve.Areviewofthecompleted datasheetsfortheperiodfrom1990to1995showedthat,NUREG-1275, Volume9,"Operating Experience FeedbackReport-PressureLockingandThermalBindingofGateValves"GenericLetter89-10,Supplement 6,"Information onScheduleandGrouping, andStaffResponses toAdditional PublicQuestions"

'NRCInformation Notice92-26,"Pressure LockingofMotorOperatedFlexibleWedgeGateValves"INPOSOERNumber84-07,"Pressure LockingandThermalBindingofGateValves"2-2

historically, theobservedseatleakageforthesevalveshasbeen>0.011gpm.Thisexceedstheminimumrequiredleakagetoreducebonnetpressurepriortoopeningtheisolation valvesfollowing apostulated MSLB.BasisforUtilizinTestSeatLeakaeThevalveflex-wedge hasagapetweenitsupstreamanownstream discs;thefluidinthisgapishydraulically connected tothebonnet.FortheobservedseatleakagetooccurduringtheTSsurveillance test,thedownstream discmustleakthroughtheseat.Seatleakagethroughthisdiscallowsthebonnettodepressurize duringanormalplantcooldownevolution, priortoopeningthevalvesforshutdowncoolingoperation.

Thecondition inthevalvesduringnormalheatup,operation andcooldownarepredicted tobeasfollows:1)Duringthe18-monthTSsurveillance test,thevalvesareseatleakagetestedwiththeRCSatapproximately 250psiatoobtainavalvedifferential pressuregreaterthan200psid.Theobservedseatleakagerequiresthatthedownstream dischavesomeleakage.2)DuringRCSheatup,thevalvesareclosedwiththeRCSandshutdowncoolingfluidat270psigand300'F.Notethatthedownstream isolation valvesV-3664andV-3665onthesamepipinglinebutoutsidecontainment arealsoclosedatthistime.3)DuringRCSheatupandsteadystateoperation, thevalvescooltoambienttemperature, andthedifferential pressurebetweentheRCSfluid(2250psia)andbonnetfluidforcestheupstreamdiscwedgeawayfromitsseat.Thebonnetfluidmaypressurize toRCSpressure, eitherduetothediscwedgebeingforcedawayfromitsseat,orduetoleakagethroughthematingsurfacesoftheseatanddiscwedge.Theupstreamvalvediscwedgewillre-seatwhenthedifferential pressureforceacrosstheupstreamdiscisminimized; thisoccurswhenbonnetpressureapproaches RCSpressure.

Iftheoutboardisolation valves(V-3481andV-3651)havealowerseatleakageratethantheupstreamisolation valves(V-3480andV-3652),thepipingbetweenthevalvesmayalsopressurize toapproximately RCSpressure.

Ifavalve'sdownstream seatleakageisgreaterthantheupstreamvalvewedgeleakage,thebonnetmaynotpressurize significantly; thiscouldpressurize downstream pipingandcausepressurereliefvalvesV-3666orV-3667(335psigsetpoint) toliftanddischarge intothecontainment sump.Reliefvalvedischarge couldbeobservedbychangesinthecontainment sumplevel,bytheRCSleakagedetection system,orasRCSleakage.DuringRCScooldownthevalvebonnetandpipingbetweenthevalveswilldepressurize, duetothemeasuredseatleakagethroughthedownstream valvewedge.Thetimefromreactortriptoenteringshutdowncoolingistypically 8hours.2-3 0

4)IfadesignbasisMSLBoccurs,theRCSwoulddepressurize to500psiainapproximately 80seconds.Plantoperators maycommencearapidcooldowntoshutdowncoolingentryconditions in3hours.Sincethevalveshaveahistoryofminorseatleakagethroughtheupstreamanddownstream wedgesandseatsatlowdifferential

pressure, itisexpectedthatvalveseatleakagewouldoccurunderpost-MSLB conditions toreducebonnetpressure.

However,thedifference betweenaMSLBcooldownandanormalcooldownisthatthereisonlya3hourversus8hourcooldownperiod,andthevalvesandpipingwillheatupandpressurize becausecontainment ambienttemperature willincreaserapidly.Undertheseconditions, therequiredvalveseatleakageraterequiredtoreducethepressureinthevalvebonnetandpipingfromRCSpressuretotheshutdowncoolingsystemdesignpressurein3hoursis0.0011gpmforvalveV-3651and0.004gpmforvalvesV-3480andV-3652.Therequiredvalveseatleakagetotheshutdowncoolingsystemismuchlessthantheobservedseatleakageratedetermined bytheTSsurveillance test.Toensurethecontinued operability oftheshutdowncoolingisolation valvesafterFall1995St.LucieUnit2refueling outage(SL2-9),plantpersonnel verifiedthattheobservedseatleakagewasatleast0.01gpmforV-3480andV-3652,andatleast0.015gpmforV-3651.Thisleakagerateprovidesa35%marginbetweenmeasuredandrequiredseatleakage.BasisforExtendinCorrective ActionUntil1997RefuelinOutaeTeparmedcorrective actionwastriaimpementeonV-48duringtheFall1995SL2-9refueling outageandwillbereplicated ontheremaining threevalvesduringthenextrefueling outage.Inaddition, theplannedcorrective actionsforV-3480andV-3652willrequireafreezesealand/orafullcoreoffload.Topermitbetterintegration ofthemodifications intotherefueling outageactivities, theremaining modifications weredelayeduntiltheSpring1997St.LucieUnit2refueling outage(SL2-10).

Deferring corrective actionuntilthenextoutageisnotasafetyissueforthefollowing reasons:Theshutdowncoolingisolation valvesarenotrequireduntil3hoursafterapostulated accident.

Bythattime,thebonnetpressureandpipingpressurewilldecaytoanacceptable value,basedontheactualobservedvalveseatleakage;2)Noincidence ofthesevalvesfailingtoopenhaseverbeenidentified oneitherSt.Lucieunit.Noincidence ofpressurelockinghasbeenreportedtothevalvevendor,orlistedinthereviewedindustrydata;and2-4 0

Theaffectedvalveswouldbeprioritized asmediumpriorityusingNRCGL89-10guidelines.

FormediumpriorityMOVs,theNuclearEnergyInstitute (NEI)guidancerecommends thattheresources areappropriately appliedrelativetosafetysignificance andpriorityoftheMOV.2-5 l~0'0