ML17328A524
| ML17328A524 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 12/29/1989 |
| From: | ALEXICH M P INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG |
| To: | MURLEY T E NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML17328A525 | List: |
| References | |
| AEP:NRC:0900H, AEP:NRC:900H, NUDOCS 9001090184 | |
| Download: ML17328A524 (21) | |
Text
ACCELERATEDDISTRIBUTIONDEMONSIRQIONSYSFEMREGULATORYINFORMATIONDISTRIBUTIONSYSTEM(RIDS)IACCESSIONNBR:9001090184DOC.DATE:89/12/29NOTARIZED:NODOCKETFACIL:50-315DonaldC.CookNuclearPowerPlant,Unit,1,Indiana&05000315.50-316DonaldC.CookNuclearPowerPlant,Unit2,Indiana&05000316AUTH.NAMEAUTHORAFFILIATIONALEXICH,M.P.IndianaMichiganPowerCo.(formerlyIndiana&MichiganEleRECIP.NAMERECIPIENTAFFILIATIONRMURLEY,T.E.OfficeofNuclearReactorRegulation,Director(Post870411,I
SUBJECT:
ApplicationforamendstoLicensesDPR-58&DPR-74,modifyingTechSpecs3/4.6.5.1&3/4.6.5.3.DDISTRIBUTIONCODE:A001DCOPIESRECEIVED:LTRENCLSIZE:TITLE:ORSubmittal:GeneralDistributionNOTESRECIPIENTIDCODE/NAMEPD3-1LAGIITTER;J.INTERNAL:NRR/DET/ECMB9HNRR/DST8E2NRR/DST/SICB7ENUDOCS-ABSTRACTOGC/HDS1RES/DSIR/EIBEXTERNALLPDRNSICCOPIESLTTRENCL11551111111110111111RECIPIENTIDCODE/NAMEPD3-1PDNRR/DOEA/OTSB11NRR/DST/SELB8DNRR/DST/SRXB8E/NRCPDRCOPIESLTTRENCL111'11111101111DSANOTETOALL"RIDS"RECIPIENTS:PLEASEHELPUSTOREDUCEWASIElCONTACTTHE,DOCUMENI'ONTROLDESK,'ROOMPl-37(EXT.20079)TOELIMINATEYOURNAMEFROMDISIRIBUTIONLISTSFORDOCUMENTSYOUDON'TNEEDtTOTALNUMBEROFCOPIESREQUIRED:LTTR21ENCL19
)1(IfE('\V~*IJ>,IIy~)/'5gt~
IndianaMichiganPowerCompanyP.O.Box16631Cotumbus,OH43216ÃEHNMSlHSlMCMEGQHPQWMAEP:NRC:0900HDonaldC.CookNuclearPlantUnits1and2DocketNos.50-315and50-316LicenseNos.DPR-58andDPR-74ICECONDENSERTECHNICALSPECIFICATIONSU.S.NuclearRegulatoryCommissionDocumentControlDeskWashington,DEC.20555Attn:T,E.MurleyDecember29,1989
DearDr.Murley:
ThisletteranditsattachmentsconstituteanapplicationforamendmenttotheTechnicalSpecifications(T/Ss)fortheDonaldC.CookNuclearPlantUnits1and2.Specifically,weproposetomodifyT/S3/4.6.5.1(IceCondenserIceBed)andT/S3/4.6.5'(IceCondenserDoors).ThejustificationsfortheproposedchangesandouranalysesconcerningsignificanthazardsconsiderationsarecontainedinAttachment1tothisletter.TheproposedrevisedT/SpagesarecontainedinAttachment2.BothunitsatCookNuclearPlantoperateonan18-monthfuelcycle.ExistingT/Ssrequirecertainicecondensersurveillancestobeperformedatninemonths.Sincesomeofthesesurveillancescannotbeperformedatpower,amid-cycleoutagelastingatleastthreetofivedaysisrequired.Attachment1tothisletterprovidesjustificationforextendingthesurveillanceintervalforthesubjectT/Ssfromninetoeighteenmonths.Asindicated,theproposedamendmentisnotexpectedtohaveanadverseimpactonthepublichealthandsafety.Implementationofthechangewill,ontheotherhand,eliminatetheneedforaplantshutdownduringeachfuelcycle,andtherebycontributetooverallplantsafetybyreducingthenumberofshutdown/startuptransientstheplantwillexperience.Foryourinformation,thenextscheduledmid-cycleoutageforicecondenserinspectionisJanuary5,1990forUnit2.900i090184891229PDRADOCK05000ai5PDC Dr.T.E.Murley-2-AEP:NRC:0900HWebelievethattheproposedchangeswillnotresultin(1)asignificantchangeinthetypesofeffluentsorasignificantincreaseintheamountsofanyeffluentthatmaybereleasedoffsite,or(2)asignificantincreaseinindividualorcumulativeoccupationalradiationexposure.ThesechangeshavebeenreviewedbythePlantNuclearSafetyReviewCommitteeandtheNuclearSafetyandDesignReviewCommittee.Incompliancewiththerequirementsof10CFR50.91(b)(1),copiesofthisletteranditsattachmentshavebeentransmittedtoMr.R.C.CallenoftheMichiganPublicServiceCommissionandtotheMichiganDepartmentofPublicHealth.ThisdocumenthasbeenpreparedfollowingCorporateproceduresthatincorporateareasonablesetofcontrolstoensureitsaccuracyandcompletenesspriortosignaturebytheundersigned.Sincerely,M.P.AxichVicePresidentMPA/ehAttachmentscc:D.H.Williams,Jr.A.A,Blind-BridgmanR.C.CallenG.CharnoffA.B.DavisNRCResidentInspector-BridgmanNFEMSectionChief ATTACHMENT1TOAEP:NRC:0900HJUSTIFICATIONAND10CFR50.92ANALYSESFORCHANGESTOTHEDONALDC.COOKNUCLEARPLANTUNITNOS,1AND2TECHNICALSPECIFICATIONS
Attachment1toAEP:NRC:0900HPage1I'ntroductionandBackroundThislicenseamendmentrequestproposestomodifyT/S3/4.6.5.1(IceCondenserIceBed)andT/S3/4.6.5.3(IceCondenserDoors).TheproposedchangesareintendedtopositionCookNuclearPlantUnits1and2sothatmid-cycle(9-month)outagesforicecondensersurveillancescanbeeliminated.Specifically,therequestedchangeswilleliminatetheneedtoshutdowntoMode3toperformthefollowingsurveillances:(1)visualinspectionoftheicecondenserturningvanesandlowersupportstructureforfrostandiceaccumulation(T/S4.6.5.l.b.3)and(2)opening/closingtorquetestingoftheicecondenserinletdoors(T/S4.6.5.3.1.b).OthersurveillancesrequiredbyT/S4.6.5.1.b.3,i.e.iceweighingandflowpassageinspectionsintheicebedabovethelowersupportstructureandtheturningvanes,areunaffectedbythisrequestandwouldstillbeperformedeveryninemonthswhileatpower.Eliminatingtheneedforamid-cycleoutagecanbeaccomplishedbyanextensionofthesurveillanceintervalforthelowersupportstructureandturningvanevisualinspectionsandinletdoorinspectionsto18months.Basedonourexperiencetodate,therequestedextensionofthesurveillanceintervalto18monthshasinsignificantimpactonsafetyand,toadegree,contributestooverallsafetybyeliminatingoneshutdown/startuptransientpercycle.Thesafetyimpactoftherequestedchangesisdiscussedbelow.AfootnotetoT/S3/4'.5.1oftheUnit2T/Ssisalsobeingdeletedasaneditorialchangebecauseitisnolongerapplicable.II.TechnicalSecificationChane-IceCondenserIceBedFlow~PassaesThetechnicalbasisforthesurveillancerequirementsforicecondensericebedflowpassagesistoprovidereasonableassurancethatthereisadequateflowareathroughtheicecondenserfollowingaloss-of-coolantaccident(LOCA)orahighenergylinebreak(HELB).TheT/Scallsforverifyingatleastonceeveryninemonths,byavisualinspectionofatleasttwoflowpassagespericecondenserbay,thattheaccumulationoffrostoriceonflowpassagesbetweenicebaskets,pastlatticeframes,throughtheintermediateandtopdeckfloorgrating,orpastthelowerinletplenumsupportstructuresandturningvanesisrestrictedtoanominalthicknessof3/8inches.Theproposedchangewouldreviseonlythesurveillanceintervaltoperformthevisual Attachment1toAEP:NRC:0900HPage2inspectionofthelowerinlet,plenumsupportstructuresandturningvanesfromninemonthstoeighteenmonths(i.e.,atrefuelingoutages).Theacceptancecriteriafortheseinspectionswouldremainunchanged.Theexistingsurveillanceintervalsoninspectionofflowpassagesbetweenicebaskets,pastlatticeframes,throughtheintermediatedeckandthroughthetopdeckgratingeveryninemonthswouldberetained.However,notethattheorderthatthesecomponentsappearinT/S4.6.5.1.b,3hasbeenchangedtobeconsistentwitha"top-down"inspectionoftheicecondenser.Giventhatonlytheorderofthecomponentsischanged,thischangeisconsiderededitorial.Thelowersupportstructureisdesignedtosupportandholddowntheicebasketsintherequiredarray.Xtisalsodesignedsuchthatthereisanadequateareafortheair/steammixturetoflowintotheicebedintheeventofaLOCAorHELB~Thelowersupportstructurehasturningvanesthataredesignedtoturntheflowupthroughtheicebedintheeventofanaccident,Forsuchanevent,thevaneswouldservetoreducethedragforcesonthelowersupportstructuralmembers,reducetheimpingementforcesonthecontainmentwallacrossfromthelowerinletdoorsanddistributetheflowmoreuniformlyovertheicebed.Todetermineifoperationalhistorysupportedextendingthesurveillanceinterval.to18monthsfortheseT/Ss,areviewwasconductedoftheCookNuclearPlantLicenseeEventReports(LERs)andplantconditionreportssince1981(thisdatewasselectedarbitrarily).Anyevidenceofexcessivefrostoricebuildupinthelowersupportstructurewouldbereportedinthesedocuments.Basedonthesedocuments,noconditionscouldbeidentifiedwheretheT/Ssurveillancecriteriaonaccumulationoffrostoriceinthelowerinletplenumsupportstructureflowpathoronturningvaneswerenotmet.TheconclusionsfromthisreviewandfromdiscussionswithCookNuclearPlantpersonnelinvolvedwithicecondensersurveillancewerethatoperatingexperiencesupportstheextensionofthesurveillanceintervalto18monthsforthelowersupportstructureandturningvanes.Thephysicaldesignoftheicecondenserwasalsoconsideredintheevaluation.Theicebeditselfistheportionoftheicecondenserwiththeleastamountofflowarea.Experiencealsoindicatesthatitisthelocationwheremostofthe Attachment1toAEP:NRC:0900HPage3frostandiceaccumulationoccursduetosublimation.Thus,anyevidenceofabnormaldegradationoftheicecondenserwillbefoundduringthenine-monthsurveillanceoftheicebed.Per10CFR50,92,aproposedamendmentwillnotinvolveasignificanthazardsconsiderationiftheproposedamendmentdoesnot:(1)involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated.(2)createthepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyanalyzedorevaluated,or(3)involveasignificantreductioninamarginofsafety.Criterion1TheicecondenserisapassivesystemthatperformsamitigativefunctiontoreducecontainmentpressurizationfollowingaLOCAorHELB.Therefore,theproposedchangeinthesurveillancefrequencyforinspectionoffrostandiceaccumulationonthelowerinletplenumsupportstructureandturningvaneswouldnotincreasetheprobabilityofanaccidentpreviouslyevaluated.Themainimpactofflowpassageblockagesisontheshort-termcontainmentsubcompartmentpressuresfollowingaLOCA.Blockagesresultinreducedflowareasintheicecondenserandhencehigherupstreampressureduringtheblowdownphaseoftheaccident.Asstatedearlierinthisattachment,duringsurveillanceinspectionsoftheicecondenserturningvanesandlowerinletplenumsupportstructureflowpaths,noevidencehasbeenfoundthatfrost/iceaccumulationhasexceededtheT/Srequirement.Inaddition,theconsequencesofflowpassageblockageintheicecondenserhavealreadybeenevaluated.Forexample,ourletterAEP:NRC:1067datedOctober14,1988,andsupplementedbyourletterAEP:NRC:1067CdatedMarch14,1989,transmittedtheresultsofsubcompartmentanalysestosupportoperationofUnit1forthereducedtemperatureandpressureprogram.Intheseanalysesa15'tflowblockageintheicecondenserwasassumed.TheseanalyseswereapprovedinasafetyevaluationreportattachedtoyourletterdatedJune9,1989(TACNo,71062),Similarevaluationshavebeenperformedby Attachment1toAEP;NRC:0900HPage4Westinghousefora20%flowblockageforUnit2operatingconditions.Insummary,theproposedT/Schangewillnotincreasetheconsequencesofapreviouslyanalyzedaccidentbecauseflowblockagehasbeenaccountedforintheaccidentanalysesandoperatingexperienceindicatesthatthisparticularareaoftheicecondenseris.notverysusceptibletofrost/iceaccumulation.Criterion2Thesurveillanceintervalincreaseto18monthswillnotresultinachangeinplantconfigurationoroperation.Further,asindicatedabove,theicecondenserisapassivesystemthatonlyperformsamitigativefunctionfollowingcertainaccidents.Therefore,thischangewillnotcreatethepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyanalyzedorevaluated.Criterion3TheicecondenserperformsthemitigativefunctionoflimitingcontainmentpressurebuildupfollowingaLOCAorHELB.Toensurethattheicecondenserwillfulfillitsfunction,buildupoffrostandiceintheflowpassageareamustbelimited.However,thereareallowancesforfrost/icebuildupassumedinthesafetyanalysisasindicatedabove.Therequestedchangeincreasesthesurveillanceintervalforanareawithintheicecondenserthat,basedonoperatingexperience,isnotverysusceptibletofrost/icebuildup.Further,surveillanceinspectionsoftheflowpassagesintheicebedwill'ontinuetobeperformedeveryninemonthsfortheareaoftheicecondenserthatismostsusceptibletofrost/icebuildup.Therefore,itisapparentthattheproposedT/Schangewillnotinvolveasignificantreductioninthemarginofsafety.Lastly,wenotethattheCommissionhasprovidedguidanceconcerningthedeterminationofsignificanthazardsbyprovidingcertainexamples(48FR14870)ofamendmentsconsiderednotlikelytoinvolvesignificanthazardsconsideration,Thesixthoftheseexamplesreferstochangesthatmayresultinsomeincreasetotheprobabilityofoccurrence'rconsequencesofapreviouslyanalyzedaccident,buttheresultsofwhicharewithinlimitsestablishedasacceptable.Webelievethischangefallswithinthescopeofthisexample.Thisrequesttoincreasethesurveillanceintervalmayresultinsomeincreaseintheprobabilityoffrostandiceaccumulationontheicecondenserlowersupport Attachment1toAEP:NRC:0900HPage5structureandturningvanes.However,basedonplantoperationalexperience,thedegreeofflowblockagewi11bewithinthelimitsofthesafety.analysisandthereforetheconsequencesarenotincreased.Vebelievethischangedoesnotinvolveasignificanthazardsconsiderationasdefinedin10CFR50.92.III'echnicalSecificationChane-IceCondenserInletDoorsTheT/Sbasis(3/4.6.5,3)foricecondenserdoorsstatesthattheoperabilityoftheicecondenserdoorsandtherequirementthattheybemaintainedclosedensures1)thatthereactorcoolantsystemfluidreleasedduringaLOCAwillbedivertedthroughtheicecondenserbaysforheatremovaland2)thatexcessivesublimationoftheicebedwillnotoccurbecauseofwarmairintrusion.Excessivesublimationiscontrolledduringnormaloperationthroughcontinuouslymonitoringanddeterminingtheinletdoorsclosedusingtheinletdoorpositionmonitoringsystem(T/S4,6,5.3.1.a).Toverifythatthedoorswillopenduringanaccident,T/S4.6.5.3.l.brequiresthatonehalfoftheicecondenserinletdoorsbedemonstratedoperableduringshutdownatleastonceeveryninemonths.TheproposedT/Schangeswouldrequirethatthesurveillancetestingonalllowerinletdoorsbeperformedatleastonceevery18months,TheproposedchangeforinletdoorsurveillancesisidenticaltothatpreviouslyapprovedfortheMcGuireandCatawbaNuclearStations.(Forthesafetyevaluation-reportonthischange,seeHood,NRC,toTucker,DukePower,"IssuanceofAmendmentNo.83toFacilityOperatingLicenseNPF-9andAmendment64toFacilityOperatingLicenseNPF-17-McGuireNuclearStation,Units1and2,"datedMay11,1988.)TheprimarypurposeofthelowerinletdoorsurveillanceistodeterminethatthedoorsarecapableofopeningproperlywhenrequiredduringaLOCAorotherhighenergylinebreak.Thisensuresthatthesteamreleasedinthelowercontainmentcompartmentcanentertheicecondensercompartmentandbecondensedbytheiceinside.Thelowerinletdoorsareequippedwithspringsthatproduceasmallforcetoresistdooropeningduringnormaloperation.Thedoorsarenormallyheldshut,againstasealmountedontheframe,bythestaticdifferentialpressureduetothehigherdensityairintheicecondensercompartment.Wi.thzerodifferentialpressureacrossthedoors(nocoldairhead),theneutralpositionofthespringissetsothatthedoorsareslightlyopen
Attachment1toAEP:NRC:0900HPage6(3/8"+1/8").Thespringtorqueisthensetsothatthedoorswillopenrapidlyinresponsetoalowercontainmentpressureincreaseduringalinebreak.Thespringtorqueaidsinpreventingmaldistributionofflowthroughthe24pairsoflowerinletdoorsduringasmalllinebreakaccidentwhenthedoorswouldonlyopenpartially.Thesurveillanceinquestionrequiresthatvariousmeasurementsbemadeofdoorspringtorque,inordertoensurethattherequiredsafetyfunctionscanbemet.Thesemeasurementsincludeinitialopeningtorque,openingtorque,closingtorqueanddoorfrictionaltorque.Theinitialopeningtorqueisthetorquerequiredtoopenthedoorwhenthedoorisclosedandisagainstthedoorseal.Theopeningtorqueandclosingtorquearemeasuredwhenthedoorisopen40degrees.Thedoorfrictionaltorqueiscalculatedbasedontheopeningandclosingtorques.TheproposedT/Schangeswouldnotchangetheacceptancecriteriafortheabovetorquemeasurementsbutwouldrevisethesurveillanceintervalontheicecondenserinletdoorsfromninemonthsto18months(i.e.,atrefuelingoutages).Further,whilethecurrentT/Srequirestestingof50tofthedoorseveryninemonths,theproposedT/Swouldrequiretestingallofthedoorsevery18months.Inthisway,theintervalforcompletetestingofanyonedoorwillremainunchangedfromthecurrentsurveillanceinterval,Todetermineifoperationalhistorysupportedextensionofthesurveillanceintervalto18months,areviewofplantLERsandconditionreportssince1981wasconducted.Theyear1981wasselectedarbitrarily.Since1981,theCookNuclearPlantUnits1and2icecondenserinletdoorshavefailedT/Ssurveillancecriteriaonsevenoccasions.ThereasonsforthefailureofinletdoorstomeetT/Srequirementsandthecorrective/preventiveactionstakenarehighlightedbelow.InaJune1983surveillanceitwasfoundthatoneUnit2inletdoorexceededtheacceptancecriteriafortheinitialopeningtorque.Aninspectionofthedoorfoundthattheproblemwastheresultoftheframesealsinitiallystickingtothedoorbecauseofglycolontheseal.Thesealwascleanedandthedoortestedsatisfactorily,Nofurtheractionwasperformedbecausetheincidentwasconsideredisolated.InasurveillanceperformedinAugust1983,itwasfoundthatfiveUnit2inletdoorsexceededtheacceptancecriteriafor
Attachment1toAEP:NRC:0900HPage7initialopeningtorque,Theinvestigationrevealedthatthreeofthedoorsrequiredad]ustmentstothedoorframeandonedoorwasclosedonalooseRTDcable,Thecablewasremovedandsecured.Theremainingdoorwasinspectedandthesealswerecleaned.Topreventrecurrence,theappropriateproceduresweremodifiedtoensurethatalldoorsarefreeofobstructionsandthatthesealsandsealingsurfacesarefreeofdebristhatcouldcausebindingfollowingcompletionoficebasketweighing.InJune1984,twoUnit2inletdoorsfailedtheacceptancecriteriaintheT/Ss.Onedoorexceededtheopeningtorquebyasmallamount(198inch-lbwhiletheT/Scriteriais195inch-lb).Theinvestigationfoundthatthedoorbumper(shockabsorber)coverhadanaccumulationoficebehinditandwasrestrictingthedoormovement.Theicewasremovedandthedoorretestedsatisfactorily.Theappropriateprocedurewasrevisedtoincludeaninspectionforiceaccumulationinthedoorbumper.Theotherdoorfailedtheacceptancecriteriaforclosingtorquebyasmallamount(76.4inch-lbversustheT/Scriteriaof78inch-lb).Thedoorwasretestedandfoundtobeacceptable.Nofurtheractionsweretaken.InAugust1984,oneUnit1inletdoorfailedthehingefrictionaltorquetest(althoughpassingtheinitialopeningtorque,openingtorqueandclosingtorquetests).Duringinspectionofthedoor,aniceaccumulationwasfoundbetweenthedoorbumperandthebumpercover,Theicewasremovedandthedoorretestedsatisfactorily,Theiceaccumulationoccurredasaresultoffreshicebeingblownintosomebasketsintheparticularbaywherethefailureoccurred,Duetotheshortnessoftheoutage,inletdoortestingwasscheduledtobecompletedpriortothefinalinspectionforiceaccumulationinthelowerpartoftheicecondenser.TheicewouldhavebeenremovedpriortopoweroperationduringtheicecondenserfinalinspectionasrequiredbytheprocedurechangesimplementedasaresultoftheJune1984eventdiscussedabove.InaDecember1984surveillance,oneUnit2inletdoorexceededtheacceptancecriteriaforinitialopeningtorque.Thedoorwasinspectedandadryresiduewasfoundonthedoortopseal.Thesealwascleanedandthehingeslubricated.Thedoorwouldhaveopenedatadifferentialpressureofonlyabout1.3poundspersquarefoot(psf)ratherthan1psf,whichisthebasisfortheacceptancecriteria.
Attachment1toAEP:NRC:0900HPage8InJanuary1985,14of48Unit1inletdoorsfailedtomeettheacceptancecriteriaforinitialopeningtorque(althoughalldoorsdidopen).Inonlythreecasesdidbothdoorsinaparticularbayfailtomeettheacceptancecriteria.Adifferentialpressureofonlyabout1.1psfwouldhaveopenedatleastonedoorineachofthesethreebays,Therefore,atadifferentialpressureof1.1psf,allbayswouldhavehadatleastonedooropen.Doorswhichfailedwereretestedtodetermineiftheproblemwaswiththedoorsealsorthedoorhinges.Theretestindicatedthattheproblemwaswiththeseals'opreviousfailuresofthistypehadbeenfound.Althoughthedoorsealswereinspectedandfoundtobeveryclean,testpersonnelbelievethatlightfrosthadcausedthedoorstostickduetovaportransferbetweentheseals.Topreventthismoistureinfiltrationbetweentheseals,asiliconelubricantisnowappliedtothesealsandthenwipeddownpriortoreturntopower.InasurveillanceperformedinDecember1985,sevendoorsfailedtheinitialopeningtorqueacceptancecriteriaduetoiceaccumulation.Aftertheicewasremoved,allofthedoorspassedtheretestandshowednosignsofmechanicalfailure.AnothersurveillancewasperformedinJune1986,withalldoorssuccessfullypassing.ThefailuresfoundduringtheDecember1985surveillancearebelievedtohaveoccurredasaresultofoutageworkperformedduringtheUnit11985refuelingoutage,Someofthisworkinvolveddeliberatedefrostingoftheicecondenser,andwasdoneaftertheSeptember1985inletdoorsurveillanceswereperformed.Itisbelievedthatwaterandicefromthedefrostoperationaccumulatedonthedoors,causingtheopeningtorquestoexceedT/Slimits.Topreventrecurrence,theicecondenserdefrostprocedurenowrequiresthatthedooropeningtorquesbetestedfollowingadefrostoperation.Otheradditionalpreventivemeasureshavealsobeenimplementedasfollows.Operationspersonnelarerequiredbyproceduretomakeacontainmentcloseoutinspectiontourpriortostartupafteranextendedoutage,Thisinspectionincludeslookingforfrostbuildupondoors.Astephasalsobeenaddedtotheoperationdepartmentsplantheatupprocedurethatrequiresanevaluationandsignoffbytheperformancedepartmentoftheneedtoperformalowerinletdoorsurveillancetestbasedonconditionsintheicecondensezsincetheprevioussurveillancetest.Forexample,unusuallyhighicebedtemperatureduringanoutageisaconditionthatwouldrequirearetestofthedoors.
Attachment1toAEP:NRC:0900HPage9ThepurposeofdetailingtheT/Ssurveillancehistoryoftheinletdoorsistodemonstratethateitherfailureshavebeensingle,isolatedoccurrencesoreffectivecorrectiveactionshavebeenimplementedthroughdoorsealmaintenanceoradditionaldoorinspectionsmandatedbyprocedures.Asaresultoftheseefforts,noinletdoorsatCookNuclearPlanthavefailedanyoftheT/Sacceptancecriteriarelatedtoinitialopeningtorque,openingtorque,closingtorqueorhingefrictiontorquesinceDecember1985inUnit1andDecember1984inUnit2.Further,thefailuresidentifiedpriortoDecember1985werelargelyconfinedtothedoorsealsandiceaccumulationandnottothehingesorspringsonthedoors,thusconfirmingthedesignadequacyofthedoorsthemselves.Themechanicaldesignoftheinletdoorsisextremelysimpleinordertoreducethechancesofanymalfunction.Thedoorhingesaredesignedtopreventgallingorselfwelding,Thelong-termperformanceandcorrosionofthedoorhingesandrelatedhardware,whenexposedtotheicecondenseratmosphere,hasbeenconsideredintheicecondenserdesign.Thelowtemperature(10F-20F)andlowabsolutehumidityoftheicecondenseratmosphereresultsinnegligiblecorrosionofuncoatedcarbonsteel.Toensurethatcorrosionisminimizedwhilethecomponentsareinoperationinthecontainment,componentswereeithergalvanizedorpainted.GalvanizingwasinaccordancewithASTM,A123andpaintinginaccordancewithAmericanNationalStandardsInstituteANSIN101.2-72,"ProtectiveCoatings(Paints)forLightWaterNuclearReactorContainmentFacilities."Materials,suchasstainlesssteels,withlowcorrosionrateswereusedwithoutprotectivecoatings.Anyicecondenserequipmentwhoseperformancemightbeaffectedbycorrosionemployscorrosionresistantmaterialforcriticalcomponents.Thus,corrosionhasbeenconsideredinthedetaileddesignoftheicecondensercomponents,andithasbeendeterminedthattheperformancecharacteristicsoftheicecondensermaterialsofconstructionarenotimpairedbylong-termexposuretotheicecondenserenvironment.ThishasbeenconfirmedwithregardtotheinletdoorsbytheoperatingexperienceofCookNuclearPlant.JustificationfortheproposedincreaseintheT/Ssurveillanceintervalisbased,inpart,onthereliabledesignoftheinletdoors,theprogrammaticimprovementsmadeatCookNuclearPlantwithregardtodoorsealmaintenanceandinletdoorinspectionsandtherecenthistoryofhighly Attachment1toAEP:NRC:0900HPage10reliableperformanceofthedoorswithregardtoT/Ssurveillancetests.Per10CFR50.92,aproposedamendmentwillinvolvenosignificanthazardsconsiderationiftheproposedamendmentdoesnot:(1)involveasignificantincreaseintheprobabilityorconsequencesofanaccidentpreviouslyevaluated,(2)createthepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyanalyzedorevaluated,or(3)involveasignificantreductioninamarginofsafety,Criterion1TheproposedT/Samendmentwouldnotinvolveanyincreaseintheprobabilityofpreviouslyevaluatedaccidents.TheicecondenserisapassivemitigativesystemdesignedtolimitthecontainmentpressureafteraLOCA'orHELB;noaccidentsevaluatedintheFSARareinitiatedbyicecondensercomponents.Theproposedamendmentwouldalsonotinvolveanyincrease'intheconsequencesofapreviouslyanalyzedaccident.Theicecondenserdoorsservetwodistinctfunctions;1)tostayclosedduringnormaloperationand2)toopenduringaLOCAorHELB.The.doorpositioniscontinuouslymonitoredduringnormaloperationtoensurethattheicecondenserinletdoorsareclosedtoprotecttheicebedfromheatsources.Thedoorsarehunginaneutralpositionandareslightlya]arwhenthedifferentialpressureacrossthedooriszero.Thedoorsareheldagainstthegasketsealsbythesmallcoldairheadofonepoundpersquarefootintheicecondenserduringnormaloperation.TheT/Sacceptancecriteriaoninitialopeningtorqueisbasedonthisdifferentialpressure,Foralargebreakloss-of-coolantaccident(LBLOCA),thepeakdifferentialpressurebetweentheloweranduppercompartmentsofthecontainmentisatleast7,5psiwhichisontheorderof1000poundspersquarefoot.Therefore,thereislittlelikelihoodthatanyinletdoorwillremainclosedduringaLBLOCAorlargeHELB.
Attachment1toAEP:NRC:0900HPagellForasmallbreakloss-of-coolantaccident(SBLOCA),theinletdoorsareequippedwithspringswhichaidinpreventingmaldistributionofflowthroughthedoorswhenthedoorswouldonlypartiallyopeninordertoassureequalflowthroughalldoorpairs.Inaddition,duringthedesignoftheinletdoors,ananalysiswasperformedtodeterminehowmanycouldremainshutandstillpermitthesatisfactoryoperationoftheicecondensersystem.ThisanalysisisdiscussedinSection6.9.3.1ofAppendixMoftheupdatedFSAR.Thelimitingcaseformaximummaldistributionfortheworse-casebreaklocationandbreaksizefoundthat21inletdoorscouldremainclosedwithoutexceedingtheicebedcapacityofthesectionoftheicebedreceivingthemaximumsteam/airflow.Giventhereliabilityofthedoors,theimprovementsindoorsealmaintenanceandimplementationofstricterinspectionprocedures,itisnotexpectedthatextendingthesurveillanceintervalfortheinletdoorsto18monthswillhaveanyappreciableeffectonthelikelihoodofadoorfailingtomeettheT/Srequirement.TheconsequencesofanaccidentpreviouslyevaluatedarenotincreasedbecausethepossibilityofalargenumberofinletdoorsremainingshuthasalreadybeenconsideredforaSBLOCAandfoundtohaveacceptableconsequencesasdiscussedabove.Criterion2Thesurveillanceintervalincreaseto18monthswillnotresultinachangeinplantconfigurationoroperation,Therefore,thischangewillnotcreatethepossibilityofanewordifferentkindofaccidentfromanyaccidentpreviouslyanalyzedorevaluated.Further,asindicatedabove,theicecondenserisapassivesystemthatonlyperformsamitigativefunctionfollowingcertainaccidents.Criterion3TheicecondenserperformsthemitigativefunctionoflimitingcontainmentpressurebuildupfollowingaLOCA(HELBisboundedbytheLOCAanalysisintermsofpressurization),Toensurethattheicecondenserwillfulfillitsfunction,theicecondenserinletdoorsmustbothinitiallyopenfollowingcertainaccidentsandperformaflowproportioning,ifrequired.TheT/Ssurveillanceacceptancecriteriaarebasedontheserequirements.ForalargebreakLOCA,theresultantdifferentialpressureacrossthedoorsissolarge ll Attachment1toAEP:NRC:0900HPage12ascomparedtotheacceptancecriteriathatthereislittlelikelihoodthatthedoorswillfailtoopen.Becausealldoorswillopenfully,theflowproportioningfunctionisnotrequired.ForasmallbreakLOCA,asindicatedearlierinthisattachment,thepossibilityofalargenumberofinletdoorsremainingshuthasalreadybeenconsideredandfoundtobeacceptable.GiventhattheintervalforcompletetestingofanyonedoorwillremainunchangedasaresultofthisproposedT/Schange,andthatthereliabilityoftheinletdoorshasbeenimprovedthroughsealmaintenanceandstricterinspectionprocedures,thereislittlelikelihoodthatthenumberofdoorsfailingtheT/Sacceptancecriteriawillincrease,Therefore,theproposedT/Schangedoesnotinvolveasignificantreductioninthemarginofsafety.Lastly,wenotethattheCommissionhasprovidedguidanceconcerningthedeterminationofsignificanthazardsbyprovidingcertainexamples(48FR14870)ofamendmentsconsiderednotlikelytoinvolvesignificanthazardsconsideration.Thesixthoftheseexamplesreferstochangeswhichmayresultinsomeincreasetotheprobabilityofoccurrenceorconsequencesofapreviouslyanalyzedaccident,buttheresultsofwhicharewithinlimitsestablishedasacceptable.Basedontheabovediscussion,itisnotexpectedthattheprobabilityofdoorsfailingtoopenfollowinganaccidentwouldincreaseasaresultofthisT/Schange,andthusnosignificantincreaseintheconsequencesofanaccidentwilloccur.Vebelievethischangefallswithinthescopeofthisexample.Thereforewebelievethatthischangedoesnotinvolveasignificanthazardsconsiderationasdefinedin10CFR50.92.IV.EditorialChaneInadditiontothechangesdescribedpreviously,oneeditorialchangeissuggested.ThischangedeletesthefootnoteonPage3/46-36ofUnit2T/S3/4.6.5.Thisfootnotenowreads"onaonetimebasisduringMarch/April1987outage,theweightsofthreeRow8basketsmaybesubstitutedforthreead5acentRow9baskets."Thefootnotecanbedeletedbecauseitisnolongerapplicable.Becausethischangeispurelyeditorial,itdoesnotreduceamarginofsafety,doesnotincreasetheprobabilityorconsequencesofapreviouslyanalyzedaccident,anddoesnotintroducethepossibilityofanewaccident.Therefore,webelievethesechangesdonotinvolveasignificanthazardsconsiderationasdefinedby10CFR50.92.