ML17221A565

Proposed Tech Spec 3.7.1.6,changing Action Statement to Allow 72 H to Restore Inoperable,Open Main Feedwater Isolation Valve to Operable Status

ML17221A565
Person / Time
Site:	Saint Lucie
Issue date:	12/22/1987
From:	FLORIDA POWER & LIGHT CO.
To:
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ML17221A564	List: ML17221A563 ML17221A565
References
NUDOCS 8712300081
Download: ML17221A565 (11)

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ATTACHMENTlMarked-upTechnicalSpecificationPages3/47-I0B3/47-3(withinsert)87i2300081871222iDa.~DOCK-O500OZ89---IDI9EJW4/0I7/2 I4II tPLANTSYSTEMSMAINFEEDWATERLINEISOLATIONVALVESLIMITINGCONDITIONFOROPERATION3.7.1.6EachmainfeedwaterlineisolationvalveshallbeOPERABLE.APPLICABILITY:MODES.1,2,3,and4.ACTION:MODE1Withonemainfeedwaterlineisolationlveinoperablebutopen,POWEROPERATIONmaycontinuep'rovidedheinoperablevalveisrestoredtoOPERABLEstatuswithinhours;otherwise,beinatleastHOTSTANDBYwithinthenext6hoursandinCOLDSHUTDOWNwithinthefollowing24hours.MODES2,3-Withonemainfeedwaterlineisolationvalveinoperable,and4subseqentoperationinMODE2,3,or4mayproceedprovided::a.Theisolationvalveismaintainedclosed.b.The'p>ovisionsofSpecification3.0.4arenotapplicable.Otherwise,beinatleastHOTSTANDBYwithinthenext6hoursandinCOLDSHUTDOWNwithinthefollowing24hours.SURVEILLANCEREUIREMENTS4.7.1.6EachmainfeedwaterlineisolationvalveshallbedemonstratedOPERABLEby:a.Part-strokeexercisingthevalveatleastonceper92days,a'ndb.Verifyingfullclosurewithin5.15secondsonanyclosureactuationsignalwhileinHOTSTANDBYwithTavg>515'Fduringeachreactor"shutdowne'xceptthatverificationoffullclosurewithin5.15secondsneednotbedeterminedmoreoftenthanonceper92days.ST.LUGIE-UNIT23/47-10AmendmentNo.B

.PLANTSYSTEMSBASES3/4.7.1.4.ACTIVITYThelimitationsonsecondarysystemspecificactivityensurethattheresultantoffsiteradiationdosewillbelimitedtoasmallfractionof10CFRPart100limitsintheeventofasteamlinerupture.Thisdosealsoincludestheeffectsofacoincident1.0gpmprimaryto.secondarytubeleakinthesteamgeneratoroftheaffectedsteamlineandaconcurrentlossofoffsiteelectricalpower.Thesevaluesareconsistentwiththeassumptionsusedinthesafetyanalyses'/4.7.1.5MAINSTEAMLINEISOLATIONVALVESTheOPERABILITYofthemainsteamlineisolationvalvesensuresthatnomorethanonesteamgeneratorwillblowdownintheeventofasteamlinerupture.Thisrestrictionisrequiredto(1)minimizethepositivereactivityeffectsoftheReactorCoolantSystemcooldownassociatedwiththeblowdown,and(2)limitthepressurerisewithincontainmentintheeventthesteamlineruptureoccurswithincontainment.TheOPERABILITYofthemainsteamisolationvalveswithintheclosuretimesoftheSurveillanceRequirementsisconsistentwiththeassumptionsusedinthesafetyanalyses.3/4.7.1e6MAINFEEDWATERLINEISOLATIONVALVESThemainfeedwaterlineisolationvalvesarerequiredtobeOPERABLEtoensurethat(1)feedwateristerminatedtotheaffectedsteamgeneratorfollowingasteamlinebreakand(2)auxiliaryfeedwaterisdeliveredtotheintactsteamgeneratorfollowingafeedwaterlinebreak.Iffeedwaterisnotterminatedtoasteamgeneratorwithabrokenmainsteamline,twoseriouseffectsmayresult:(1)thepost-tripreturntopowerduetoplantcooldownwillbegreaterwithresultanthigherfuelfailureand(2)thesteamreleasedtocontainmentwillexceedthedesign.utoreovaofthminfeecckvalfromthelantdesgnanditreplaentwitsecondinfeedwaerline'tionaltheistngothertantheinfeedwelineotionalvesoreventckflowoWfolwinafednebrak.hismayre1ina1ofconensinntoryathepeialrotbeingletofethestamgeror.Theconcernisthefailureofonemainfeedwaterlineisolationvalvetoclosewiththeothermainfeedwaterlineisolationvalveinthatlinebeinginoperable(i.e.,stuckopen).Itisthusdesiredtoprecludeoperationforextendedperiodswithamainfeedwaterlineisolationva'.veknowntobestuckinthe'openposition.~X~Scnf+gs~n,k+I83/47"3 INSERT8'1Tworedundantmainfeedwaterisolationvalves(MFIV's)areprovidedineachmainfeedlinetoassurefeedwaterisolationintheeventofasteamlinebreakwithasinglefailure.Also,redundantMFIV'sassurethatbackflowinthefeedlinesispreventedfollowingafeedlinebreak.INSERTP2Atimelimitof72hoursonoperationswithaninoperablemainfeedwaterisolationvalveprovidesassurancethatoperationswillnotcontinueforanextendedperiodwithafailed,openMFIV.

ATTACHMENT2SAFETYEVALUATIONI.INTRODUCTIONTheexistingACTIONstatementfortheSt.LucieUnit2TechnicalSpecificationsSection3/4.7.1.6,MainFeedwaterIsolationValves(MFIV)allowsoperationstocontinuefour(4)hourswithaninoperable,openMFIV.ThisACTIONstatementdoesnotprovideadequatetimetoanalyzeanMFIVproblemandeffectrepairs.Asaresult,thereexiststhepotentialforunnecessaryplantshutdowns.ThisproposedchangetotheTechnicalSpecificationswillmodifytheSection3/4.7.1.6ACTIONStatementforaninoperable,openMFIVtoallowoperationstocontinueforupto72hoursinsteadofthepresentfour(4)hourlimit.IfthevalvecannotberestoredtoOPERABLE,theplantwouldbeplacedinHOTSTANDBYinthenext6hoursandCOLDSHUTDOWNwithinthefollowingtwenty-four(24)hours.II.DISCUSSIONANDANALYSISTheMPIVsarerequiredtobeOPERABLEtoensurethatfeedwaterflowtotheaffectedsteamgeneratoristerminatedintheeventofamainsteamlinebreak(MSLB).Ifmainfeedwaterflowisnotterminated,twoeffectsmayresult:(1)thepost-tripreturntopowermaybegreate'rwithresultanthigherfuelfailureand,(2)thesteamreleasetothecontainmentmayexceedcontainmentdesignpressureifthebreakisinsidecontainment.Additionally,theMFIVsfunctiontoensurethatauxiliaryfeedwater(AFW)canbedeliveredtotheintactsteamgeneratorintheeventofamainfeedlinebreak(MPLB).BackflowoftheAFWtotheMainFeedwaterSystemfollowingafeedlinebreakcouldresultinalossofcondensateinventoryandthepotentialfornotbeingabletofeedtheintactsteamgenerator.TheclosureofasingleMPIVineachfeedline,asrequiredbythesafetyanalysis,providesisolationofmainfeedwaterandavailabilityofAFWfollowingasteamlineorfeedlinebreak.ThesecondMPIVensuresthatasinglefailurewhichprecludesclosureofonevalvewillnotprecludemainfeedwaterisolationorAFWavailability.Theproposedchangeisacceptableforthefollowingreasons:(A)UndercurrentTechnicalSpecifications,operationwithaninoperable, yC~1 ATTACHMENT2Page2of3openMFIVisallowedforfourhours.IntheeventofaDesignBasisEvent(DBE)duringthisperiod,failuretoterminatefeedflowwouldrequirethat:1)thesecondMFIVinthesamelineasthefirstvalvemustalsofailopen,2)amainsteamline(orfeedline)breakmustoccurandtheaffectedsteamgenerator(orfeedline)mustbetheonefedbythelinewhichhastwofailedMFIVs,and3)thisseriesofeventsmustoccurduringtheactiontime(4.hours)identifiedintheLCO.Thelikelihoodofthissequenceofeventsoccurringisverylow.Inordertogainperspectiveonthesignificanceoftheproposedchange,from4to72hours,1)anestimatedMFIVfailopenfrequencyperNUREG2728(lE-3perdemand)canbecombinedwith2)anestimateofthefrequencyofMSLBasgivenintheZionPRA(9.4E-04)toprovideaconservativeestimateofthefailuretoterminateflowgivenaMSLBeventoccursduringoperationwithoneMFIVinoperable,open.ReviewofNPRDSdataforJanuary,1985toMay,1987revealedoneLERwrittenontheMFIVs.Therefore,anassumptionofenteringanLCOonceperyearisconservative.Usingthedescribedrationaleprovidesaconservativeestimatewhichcanhelpillustratetherelativesignificanceofachangefroma4hourtoa72houractiontime.(MFIVfailsopen)x(MSLB)x(LCOActionTime)=frequencyoffailuretoterminateflowduringMSLB(1E-03/d)x(9.4E-4/Rxyr)x(4hr)(1/8760yr/hr)=4.3E-10/d(1E-03/d)x(9'E-4/Rxyr)x(72hr)(1/8760yr/hr=7.7E-09/dTherangesof.0000000077and.00000000043aresuchlowoccurrenceeventsthatforpracticalpurposesthedifferencebetweenthetwo(7.3E-09)isnotsignificant.Asimilarargumentandlowfrequencyofoccurrencecanbedemonstratedforthefeedlinebreakscenario.B)IfanMFIVbecomesinoperableandisopen,thepresentTechnicalSpecificationSection3/4.7.1.6allowsoperationstocontinueforonlyfour(4)hourspriortoproceedingtoHOTSTANDBY.AsstatedinNUREG1024,TechSpecallowableoutagetimesforinoperableequipmenthavebeenestablishedonthebasisofengineeringjudgmentconsideringtheuseofstandardintervals(e.g.1hour,4hours,72hours,etc.).Itisalsostatedthat ATTACHMENT2Page3of3outagetimesthataretooshortcanresultinunnecessaryplanttrips,transientsandfatiguecycling.Theproposed72hourallowableoutagetimeforaninoperable,openMFIVisconsistentwiththestandardtimeintervalselectedforothersafeguardssystems.Forexample,withaninoperableEmergencyCoreCoolingSystem(ECCS)subsystem,Section3/4.5.2allowsoperationstocontinuefor72hourswhiletheredundantsubsystemisrestoredtoOPERABLE.SimilarsituationsexistwiththeContainmentSpraySystems(Section3/4.6.2)ContainmentFanCoolers(Section3/4.6.2.3),IntakeCoolingSystem(Section3/4.7.4)andComponentCoolingWaterSystem(Section3/4'.3).Ineachcase,theabovesystemshaveredundantsubsystemsandtheACTIONtimeineachTechSpecallowsoperationstocontinueforupto72hourswhileaninoperablesubsystemisrestoredtoOPERABLE.Also,theMFIVsfunctionasaportionoftheflowboundaryoftheAFWandtheproposedchangeisconsistentwiththeAFWTechSpecACTIONTIME(Section3/4.7.1.2)givenasingleinoperablecomponentinredundanttrains.Thus,anextensionoftheMFIVACTIONTIMETO72hoursprovidesthesametimetorepairaninoperablesubsystemasothersafeguardssystems.

ATTACHMENT3DETERMINATIONOFNOSIGNIFICANTHAZARDSCONSIDERATIONThestandardsusedtoarriveatadeterminationthatarequestforamendmentinvolvesnosignificanthazardsconsiderationareincludedintheCommission'sregulations,IOCFR50.92,whichstatesthatnosignificanthazardsconsiderationsareinvolvediftheoperationofthefacilityinaccordancewiththeproposedamendmentwouldnot(I)involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated;or(2)createthepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated;or(3)involveasignificantreductioninamarginofsafety.Eachstandardisdiscussedasfollows:(I)Operationofthefacilityinaccordancewiththeproposedamendmentwouldnotinvolveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated.Theproposed72hourACTIONstatementwithaninoperableMainFeedwaterIsolationValve(MFIV)isconsistentwithothersafeguardsequipmentoutagetimes.Thelikelihoodofafeedlineorsteamlinebreakwithaconcurrentfailureofthesecondvalveinthesamefeedlineisremoteduringtheoutagetime.Thus,theproposed72hourallowableoutagetimewillnotsignificantlyincreasetheprobabilityorconsequencesofanaccidentpreviouslyevaluated.(2)Useofthemodifiedspecificationwouldnotcreatethepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated.Thischangewillnotcreatethepossibilityofanewordifferentkindofaccidentfromanypreviouslyanalyzedbecauseitdoesnotintroduceanewmodeofnormaloremergencyplantoperation.Inadditiontheproposedchangedoesnotinvolveaphysicalmodificationtotheplant.(3)Useofthemodifiedspecificationwouldnotinvolveasignificantreductioninamarginofsafety.BecausefailureofthesecondMFIVinthesamefeedlinewithasimultaneousfeedlineorsteamlinebreakduringtheseventy-two(72)hourallowableoutagetimeisunlikely,thischangedoesnotinvolveasignificantreductioninamarginofsafety.Basedontheabove,wehavedeterminedthattheamendmentrequestdoesnot(I)involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated,(2)createtheprobabilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyevaluated,or(3)involveasignificantreductioninamarginofsafety;andthereforedoesnotinvolveasignificanthazardsconsideration.EJWI/035/3 1H~y"~44CtI'I"'PVPPPIPUIh.~IIIJPIJU'~PJIII1h'Iy4VE1fh..d~I4~tl'It4<~PV"tPrIP>>I~4~VP~I','IP'1411~IdA1~,a'a1I44I44~1P'h4h41tV(td-1'"41hd4tld4IIPHtlIIth~.Itk4"84((~'EHItadl,ydJPPlftl.4.14'4yP~41PP>>I4~~1,V1.~I4Il'4,-ya'P~>~~\M'IVIIflhht11PPUP"~*aTtMaltI'~IddtlI>>'1JltaII3*t4Ett441aadltItta>>C~Jr1t41I'P~E4~gPJdfya:1~I4VCtPlaJtrP~P,U,'lHIJUa411~yd'Ua,fh=I~'4n>>a4tl~~~~CPllv.P~Jiay4444't'PPl4