ML17334B758

From kanterella
Revision as of 07:13, 29 June 2018 by StriderTol (talk | contribs) (Created page by program invented by StriderTol)
Jump to navigation Jump to search
LER 98-008-01:on 980112,damaged Ice Condenser Ice Basket Removed from Unit 1 Ice Condenser.Caused by Inadequate Control of Contractors & Inappropriate Maint.Damage Beyond Threshold Will Be Repaired & replaced.W/980504 Ltr
ML17334B758
Person / Time
Site: Cook American Electric Power icon.png
Issue date: 05/04/1998
From: PISARSKY F, SAMPSON J R
INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-98-008, LER-98-8, NUDOCS 9805080084
Download: ML17334B758 (11)


Text

0CATEGORY1REGULATORY INFORMATION DISTRIBUTION SYSTEM(RIDS)~(C%1QQACCESSION NBR-9805080084 DOC.DATE:

98/05/04NOTARIZED:

NODOCKET~0.FACIL:50-,316 DonaldC.CookNuclearPowerPlant,Unit2,IndianaM0500031)/,,

AUTH.NAMEAUTHORAFFILIATION PXSARSKY,F.

XndianaMichiganPowerCo.(formerly Indiana&MichiganEleSAMPSON,J.R.

XndianaMichiganPowerCo.(formerly Indiana8MichiganEleRECXP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER98-008-01:on 980112,demaged icecondenser icebasketremovedfromUnit1icecondenser.

Causedbyinadequate controlofcontractors

&inappropriate maint.Damage beyondthreshold willberepairedEreplaced.W/980504 ltr.DXSTRXBUTION CODE:IE22TCOPIESRECEIVED:LTR ENCLSIZE:TITLE:50.73/50.9 LicenseeEventReport(LER),IncidentRpt,etc.NOTES:INTERNAL!

RECIPIENT IDCODE/NAME PD3-3PDFILED/RABEELBNRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DRPM/PECB NRR/DSSA/SRZB RGN3FILE01COPXESLTTRENCL1122111111~11111111RECIPIENT IDCODE/NAME STANG,JAEOD/SPD/RRABNRR/DE/ECGB NRR/DE/EMEB NRR/DRCH/HICB NRR/DRCH/HQMB NRR/DSSA/SPLB RES/DET/EXB COPIESLTTRENCL111111111,1111111RYDEXTERNAL:

LSTLOBBYWARDNOACPOORE,W.NRCPDR111111LITCOBRYCE,JHNOACQUEENER,DS NUDOCSFULLTXT1111110NOTETOALL"RIDS"RECIPIENTS:

PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATION REMOVEDFROMDISTRIBUTION LISTSORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUORYOURORGANIZATION, CONTACTTHEDOCUMENTCONTROLDESK(DCD)ONEXTENSION 415-2083FULLTEXTCONVERSION REQUIREDTOTALNUMBEROFCOPIESREQUIRED:

LTTR24ENCL24 r

IndianaMichiganPowerCompanyCookNuctearRantOneCookPieceBridgman, MI49I060INDIANANICHIOiAN POWERMay4,1998UnitedStatesNuclearRegulatory Commission DocumentControlDeskWashington, DC20555Operating LicensesDPR-58DocketNo.50-315DocumentControlManager:Inaccordance withthecriteriaestablished by10CFR50.73entitled~hflligp!'big1id:98-008-01 Sincerely, J.R.SampsonSiteVicePresident ImbdAttachment A.B.Beach,RegionIIIJ.R.SampsonP.A.BarrettS.J.BrewerR.WhaleD.HahnRecordsCenter,INPONRCResidentInspector

'it805080084

'at80504PDRADQCK050003ih8POR NRCFORH366(5-92).STNUCLEARREGULATORY COMHISSION LXCENSEEEVENTREPORT(LER)OVEDSYOMSHO.3150.0104 EXPIRES5/31/95ESTIMATED BURDEHPERRESPONSETOCOHPLYWITHTHIINFORMATION COLLECTION REQUEST:50.0ttRS.FORFARCOHMENTSREGARDING BURDENESTIHATETOTHINFORMATION ANDRECORDSMANAGEMEHT BRANCH(MNS7714),U.STNUCLEARREGUI.ATORY COHMISSION, 4ASHIHGTON, DC20555-0001, ANDTOTHEPAPERNORREDUCTION PROJECT(3150-0104),

OFFICE0MANAGEMENT ANDBUDGETNASHINGTON DC20503.FACILITYNAHE(1)DonaldC.CookNuclearPlant-Unit1DOCKETNUMBER(2)50.315Page1of6TITLE(4)Inadequate Contractor ControlduringMaintenance andSurveillance Activities ResultsinIceBasketDamageHONTHDAYYEAREVENTDATE5YEARLERNUMBER6SEQUENTIAL NUMBERREVISIONNUMBERREPORTDATE7HONTHOAYFACILITYNAMECook-Unit2DOCKETNUHBER50-316OTHERFACILITIES INVOLVED802129898-008010504FACILITYHAHEDOCKETNUMBEROPERATING MDOE(9)TNSREPORTISSUBMITTED PURSUANI'0.2201(b) 50.73(a)(2)(iii) 73.71(b)20.2203(a)(3)(1)

TOTHEREQUIREMENTS OF10CFR:Checkoneormore11PINERLEVEL(10)0020.2203a120.2203(a)(2)(I) 20.2203a2ii20.2203(a)(2)(iii) 20.2Z03(a)(2)(iv) 20.2203(a)(2)(v)

X20.2203a3ii20'203(a)(4) 50.36c150'6(c)(2)50.73(a)(2)(1) 50.73(a)(2)(ii) 50.73a2iv50'3(a)(2)(v) 50.73a2vfi50'3(a)(2)(viii)(A) 50.73(a)(2)(viii)(B) 50'3(a)(2)(x) 73.71oOTHER(SpecifyinAbstractbetoNandinText,NRCForm366A)NAHELICEHSEECONTACTFORTHISLER12IVIr.FrankPisarsky, Mechanical Component Engineering Supervisor TELEPHONE NUMBER(IncludeAreaCode)616/465-5901, x2607COMPLETEONELINEFOREACHCOMPONENT FALUREDESCRIBED INTHISREPORTCAUSESYSTEHCOHPONENT MANUFACTURER REPORTABLE TOHPRDSCAUSESYSTEHCOMPONENT HANUFACTURER REPORTABLE TONPRDSSUPPLEMENTAL REPORTEXPECTED14XYES(lfyes,completeEXPECTEDSUBHISSION DATE).EXPECTEDBUSHISSIOHDATE(15)MONTHDAYYEAR080398ABSTRACT(Limitto1400spaces,i.e.,approximately 15single-spaced typeMritten lines)(16)OnJanuary12,1998,withUnit1inMode5,a.damaged icecondenser icebasketwasremovedfromtheUnit1icecondenser andascopingtestwasperformed todetermine itsabilitytostructurally withstand designbasisloads.Thescopingtestresultsshowedthatthedamagedicebasketfailedwithplasticdeformation underlessthandesignbasisloads.ThiseventwasreportedviaENSonJanuary12,1998at1545hoursESTunder10CFR50.72(b)(2)(i),

asanunanalyzed condition andacondition outsidetheplant'sdesignbasis.Priortoandsubsequent tothisnotification, severalformsoficebasketdamagewereidentified including damagedupperrims,missingortomligaments, dentsandfolds.ThisLERistherefore submitted inaccordance with10CFR50.72(a)(2)(i).

Therootcauseofthiscondition hasbeenattributed toinadequate controlofcontractors, andinappropriate maintenance andsurveillance practices thatresultedindamagetotheicebaskets.Adecisionhasbeenmadetocompletely thawbothunitsicecondensers inordertoaddressavarietyofissuesidentified duringthecurrentunitoutages.Icebasketswillbeinspected toidentifydamage,anddamagedbasketswillberepairedorreplaced.

Methodsforoversight oftheicecondenser laborforcearebeingreviewed, alongwithicecrewtraining, maintenance andsurveillance practices toensuretheysupportbehaviors andtechniques toprecludefurtherbasketdamage.Thesereviewswillbecompleted andappropriate improvements willbeimplemented duringthecurrentoutages..Basedonavailable information, analysisofthevarioustypesofbasketdamageconcluded thatthebasketswouldhavefunctioned topreventcontainment overpressure.

Furtheranalysiswillbeperformed, asnecessary, onceallicebasketshavebeeninspected following icecondenser thaw

NRCFORH366AU..UCLEARREGULATORY COHHISSION ROVEDBYOHBNO.3150-0104 EXPIRES5/31/95LICENSEEEVENTCONTINUATION ESTIMATED BURDENPERRESPONSETOCOMPLYlllTHTHIIHFORMATION COLLECTIOH REQUEST:50.0HRS.FORNARCOMMENTSREGARDING BURDENESTIMATETO'-THINFORMATION ANDRECORDSMANAGEHENT BRANCH(MNB7714),U.S.NUCLEARREGULATORY COMMISSION)

NASNINGTON, DC20555-0001, ANDTOTHEPAPERNORREDUCTION PROJECTe(31500104),OFFICE0MANAGEMENT ANDBUDGETMASHINGTON DC20503'ACILITYNAME1CookNuclearPlant-Unit1DOCKETNUMBER250-315LERNUMBER6YEARSEQUENTIAL 98-008REVISION01PAGE32OF6TEXT(ifmorespaceisrequired.

useadditional NRCFoaa366A's)(17)CdIureUnit1wasinMode5,ColdShutdownUnit2wasinMode5,ColdShutdownOnJanuary12,1998,withUnit1inMode5,adamagedicecondenser icebasketwasremovedfromtheUnit1icecondenser andascoplngtestwasperformed todetermine itsabilitytostructurally withstand designbasisloads.Thescopingtestresultsshowedthatthedamagedicebasketfailedwithplasticdeformation underlessthandesignbasisloads.ThiseventwasreportedtotheNRConJanuary12,1998asanunanalyzed condition.

Priortoandsubsequent tothisnotification, severalformsoficebasketdamagewereIdentified including damagedupperrims,missingortomligaments, dentsandfolds.Eachicecondenser consistsof24bayscontaining 81icebasketsperbay,coveringanarcof300degreesinthecontainment structure.

Eachicebasketisapproximately 12inchesacrossand48feetlong,filledwithboratedice.Toperformtheirdesignbasisfunction, theicebasketsandcolumnsarerequiredtowithstand designloadstoensuretheydonotejectupwardoutoftheicebedandopenupbypassflowroutes,orimpactanddamageothericecondenser equipment, orejectoutoftheicecondenser andbecomeamissileinsidecontainment.

Thebasketsaredesignedtonotcollapsecausingadjacent'or'additional icebasketcolumnstocollapse, resulting inexcessive flowpassageway

blockage, bypassflowroutes,orundefinable heattransfergeometry.

Duringthecurrentoutages,damagewasIdentified toicecondenser icebasketsduringtoursoftheicecondenser.

Damagenotedonicebasketsincludesdamagedtoprims,tom/missing ligaments, dentsandfolds.Foldsareconsidered tobethemostsignificant damage,resulting inthebasketmaterialhasundergone plasticdeformation incompression.

Basedonpreliminary inspections performed ineachunit'sicecondenser withtheicebedintact,approximately 25basketsinUnit1and45basketsinUnit2exhibitfolds.Asimilarnumberofbasketsexhibitdents.Toprimdamageiscommon,however,itisnotstructurally significant, exceptthatitmayimpedetheabilitytoweighabasket.Theexactnumberofdamagedbaskets,considering thevarioustypesofdamage,willbedetermined asaresultofplannedinspections duringthecurrentoutages.Theobserveddamagecanbeattributed toimproperhandlingofbasketsduringmaintenance andsurveillance activities.

Becausedamageoccurredduringbasketmaintenance andsurveillance activities, andcontractpersonnel performthemajorityofthiswork,inadequate controlofcontractors isconsidered aprimarycauseforthenotedcondition.

Contributors tothiscauseincludeineffective trainingforcontractpersonnel andinadequate supervisory oversight byutilitypersonnel.

Impropersurveillance practices wasanothercontributor, sincesomeofthemoresignificant basketdamageoccurredduringattemptstomovebasketsfrombeneathduringweighing.

Damagedtoprimsandfoldsinthebasketsmostlikelyoccurredduringthebasketsweighingprocess.Theprocessofweighingbasketsrequiresliftingthebasketfromthetoprimwithaweighrig.Overtime,somebasketshavebecomefrozeninplace.Inordertofreefrozenbasketsforweighing, varioustechniques havebeenused.Onetechnique usedinthepastwas"jacking" ofbasketsfromthebottomasthebasketwaspulledfromabove.Failuretocontrolthejackingintheeventthebasketremainedfrozensometimes resultedindeformation ofthebasketandproducedafoldintheligaments nearthebasketbottom.Thepracticeofjackingbasketsfromthebottomwasdiscontinued severalyearsagotoprecludefurtherbasketdamage.

NRCFORM366AU.S.CLEARREGULATORY COMHISSION OVEDBYOHBNO.3150-0104 EXPIRES5/31/95LICENSEEEVENTCONTINUATION ESTIMATED BURDENPERRESPONSETOCOHPLYWITHTHIIHFORHATION COLLECTION REQUEST:50.0HRS.FORWARCOMHENTSREGARDING BURDENESTIMATETOTHIHFORHATION ANDRECORDSMANAGEHENT BRANCH(HNBU.S.NUCLEARREGULATORY COMMISSION, WASHINGTON, DC20555-0001, ANDTO1'HEPAPERWORREDUCTION PROJECT(3150-0104),

OFFICE0HANAGEMEHT AHDBUDGET'WASHINGTON DC20503.FACILITYNAME1CookNuclearPlant-Unit1DOCKETNUMBER250-315YEAR98LERNUMBER6SEQUENTIAL REVISION008-01PAGE33OF6TEXT(ifserespaceisrequired.

useadditional NRCFons366A's)(17)Cusn'dOthertypesofdamagecanalsooccurtobasketsduringtheweighingprocessifnotcarefully controlled.

Aspreviously noted,theweighingprocessrequiresliftingthebasketbypullingfromthetoprim.Althoughlimitsaresetonmaximumliftforces,toprimdamagecanquicklyoccurifliftforcesarenotcloselymonitored, orifloadingisappliedasymmetrically.

Damagecanalsooccurduringtheweighingprocesswhenafrozenbasketisexercised inanattempttofreeit.Stillotherobserveddamageisconsidered tobetheresultoficebasketmishandling orinappropriate maintenance activities.

Twoexamplesofthistypedamageincludeinwarddentsinareasofbasketligaments andtomligaments.

Dentsprobablyoccurredduringbasketinstallation, orperhapsduringclearingofflowpassages.

Tearsinligaments aremostlikelytheresultofprolonged contactwithapneumatic

vibrator, whichisusedforemptyingoficebaskets.Thevastmajorityoficecondenser workhasbeenperformed inthepastbyacontractlaborforce,withthecontractbeingadministered bytheEngineering department andspecifically, theSystemEngineer.

Thecontractadministration responsibility wasinaddition'o theSystemEngineer's normalroleofmanagement ofthetechnical scopeoftheicecondenser workandanalysisofsurveillance testresults.Thisbroadscopeofresponsibilities allowedonlyminimaltimeforfieldoversight ofthecontractor.

Stepswerenottakentomakeotherutilitypersonnel available foroversight ofthecontractlaborforce.Therefore, fieldsupervision forcontractworkerswaslargelyprovidedbycontractsupervisory personnel ratherthanbyutilitypersonnel.

Duringthecurrentoutages,stepsweretakentotransferresponsibility foroversight oftheicecondenser laborforcetothemaintenance department, whichretainspersonnel skilledinthesupervision ofproduction labor.Thesestepsareaimedataddressing issueswithpoorcontrolofcontractors.

TheSystemEngineerhistorically administers atrainingprogramtotheicecondenser contractpersonnel.

Thistrainingincludesguidanceonbasketweighingtechniques andonappropriate useoftoolstoavoiddamagetobaskets.However,thistraininghasapparently notbeeneffective inpreventing basketdamage.Stepsarebeingtakentooverhaulthistraining, inparttoreinforce appropriate techniques toprecludevarioustypesoficebasketdamage.Finally,thelackofadefinition.

ofwhatconstitutes "detrimental damage"wasalsoviewedasacontributor, sincetherewasnobenchmark forpersonnel togagewhetherobserveddamageresultedinanunacceptable condition.

Simplistically, anybasketdamagesufficient tochallenge thebasket'sabilitytocarrydesignloadsisconsidered detrimental damageDocumentation ofdamagetoCookPlanticebasketsinpreviouscorrective actiondocuments providesevidencethattheorganization wasabletorecognize damagedicebasketsasacondition adversetoquality.Infact,theTechnical Specifications (T/S)requireperiodicinspection ofasampleoficebasketsfordetrimental damage.However,adefinition ofdetrimental damagedoesnotexist,otherthanwordinginT/S4.6.5.1.d, whichrefertodetrimental damageas"structural wear,cracks,corrosion orotherdamage."Thislackofanobjective definition mayhavecontributed toconfusion aboutthesignificance ofthedamagedicebaskets.

NRCFORH366AU.S.CLEARREGULATORY COHMISSION OVEDBYOMBNO.31500104EXPIRES5/31/95LICENSEEEVENTCONTINUATION ESTIMATED BURDENPERRESPONSETOCOMPLYNITMTHIIHFORMATION COLLECTIOH REQUEST:50.0MRS.FORMARCOMMENTSREGARDING BURDENESTIMATETOTHINFORHATION ANDRECORDSMANAGEHENT BRANCH(MNB7714)gUSTNUCLEARREGULATORY COMMISSIONS NASHINGTON, DC20555-0001, ANDTOTHEPAPERIIOR REDUCTION PROJECT(3150-0104),

OFFICE0MANAGEMENT ANDBUDGETliASHINGTON DC20503.FACILITYNAME1CookNuclearPlant-Unit1DOCKETNUHBER250-315LERNUMBER6YEARSEQUENTIAL REVISION98-008-01PAGE34OF6TEXT(Ifcerespaceisrequired.

useadditional HRCFore3664's)(17)nasheEveOnJanuary121998,at1545hoursESTanENSnotification wasmaderegarding damagedicebasketsinaccordance with10CFR50.72(b)(2)(i),

asanunanalyzed condition andacondition outsidetheplant'sdesignbasis,following receiptofascopingloadtestresultonadamagedicebasketwithbucklingdamagenearthebasketbottomrim.Basketswithbucklingdamageareconsidered toboundothertypesoficebasketdamageidentified duringthecurrentoutagesduetothesebasketshavingundergone plasticdeformation.

ThisLERissubmitted inaccordance with10CFR50.73(a)(2)(i).

Thistestexaminedthedamagedbasket'sabilitytostructurally withstand statictestloadsequivalent totheOperational BasisEarthquake (OBE)andicebasketdeadweightloads.Thescopingtestresultsshowedthatthedamagedicebasketfailedwithplasticdeformation underadistributed lateralloadofapproximately 400IbsinI',specifies thattheicebasketshouldbeabletowithstand alateralloadequivalent toapproximately 2400Ibsdistributed overthebottom6feetofthebasketinconjunction withacompressive verticalloadof4933lbs.Thefailureofthisbasketunderlessthandesignloadswasconsidered tobeanunanalyzed condition andthuswasreportedtotheNRCper10CFR50.72.

Approximately 25basketsinUnit1and45basketsinUnit2arecurrently knowtoexhibitsimilardamage.Thedamagedicebasketswereevaluated astocompliance withthedesignbasis,operability andfunctionality.

Severaltypesoficebasketdamagewereconsidered, including toprimdamage,tom/missing ligaments, dentsandfolds.Withregardtodesignbasis,thebasketsandcolumnsofbasketsaredesignedtowithstand certaindesignloadstoprovideassurance oficebedgeometryforproperthermal/hydraulic performance oftheicecondenser duringaLOCAand/orseismictransient events.Toperformtheirdesignbasisfunction, thebasketsandbasketcolumnsaredesignedtonotejectupwardoutoftheicebedandpossiblyopenupbypassflowroutes,orimpactanddamageothericecondenser equipment, orejectoutoftheicecondenser becomingamissileinsidecontainment.

Basketsmustalsonotcollapsecausingadjacentbaskets/columns tocollapse, resulting inflowpassageway

blockage, bypassflowroutes,orunanalyzed heattransfergeometries.

Toprimdamagehasbeenreviewedanddetermined tonotbeacondition thatwouldchallenge thedesignbasisormaketheicecondenser inoperable.

Damageatthetopendofthebasketcolumnwillnotpromotetheejectionofanicebasketorcolumnfromtheicebedorpromotedetrimental damageatanyadjacenticebasketcolumns,interfacing structures orequipment.

From'theaspectofdesign,basisloads,toprimdamagemayresultinsomelocalized deformation, butitwillnotcauseorpromotecollapseofthatcolumn,ordamageadjacentbaskets,basketcolumns,interfacing structures, orequipment.

Basketswithdamagedtoprimswillmeetdesignbasisloadconditions anddonotrepresent achallenge tooperability orfunctionality oftheicecondenser.

Missingortomicebasketligaments arenotrepresented ortakenintoconsideration onanydesigndrawingsordocumentation.

However,missingligaments willnotpromotetheejectionofanicebasketorbasketcolumnfromtheicebedorpromotedetrimental damageatanyadjacenticebaskets,basketcolumns,interfacing structures, orequipment.

Theicebasketincludessubstantial margininitsabilitytoresisttensileloadsfrompotential LOCAblowdownforces.Icebasketswithmissingligaments wiilhavereducedstructural capacitytocarrylateralandcompressive loadsimposedunderdesignseismicloadcases.Themostcommonlocations formissingligaments areinthemidtoupperelevations oftheicebasketcolumnduetoicebedmaintenance operations withvibrators.

i/

HRCFORM366A~STNUCLEARREGULATORY COMMISSION LXCENSEEEVENTCONTXNUATXON OVEDBYOMBNO.31500104EXPIRES5/31/95ESTIMATED BURDENPERRESPONSETOCOMPLYWITHTHISINFORMATION COLLECTIOH REQUEST:50.0HRS.FORIIARDCOMMENTSREGARDING BURDEHESTIHATETOTHEIHFORMATIOH ANDRECORDSMANAGEHENT BRANCH.(MHBB7714),U.S.NUCLEARREGULATORY COMMISSION,

'WASHINGTON, DC20555-0001, AHDTOTHEPAPERWORK REDUCTION PROJECT(3150-0104),

OFFICEOFMANAGEMENT ANDBUDGETWASHINGTON DC20503.FACILITYNAHE1CookNuclearPlant-Unit1TEXT(ifcerespaceisrequired.

useadditional HRCFons366A's)(17)DOCKETNUMBER250-315YEAR98LERNUMBER6SEQUENTIAL REVISION008-01PAGE35OF6naAtthesehigherelevations, theverticalcompressive loadsarenotstructurally significant andifthebasketmaterialwereoverstressed incombination withlateralloads,itisprobablethatthebasketfailurewouldbeasmaillocalized lateraldisplacement orshiftinthebasketmeshligaments aroundtheareaofthemissingligaments.

Thislocalized displacement oftheicebasketsectionwouldnotcausethedamagedbaskettoimpactonadjacenticebasketcolumns.Icebasketswithmissing/damaged ligaments areconsidered tobeoutsidetheplantdesignbasis,andequatetoinoperability inthesensethatthebasketdamageisdetrimental, however,thedamagedoesnotresultintheicecondenser beingincapable ofperforming itsdesignfunctiontopreventcontainment overpressure following ahighenergylinebreakinsidecontainment.

Dentsandfoldsareconsidered tobethebounding(worstcase)condition whenevaluating safetysignificance.

Icebasketswithdentsandfoldswillhave'reducedstructural capacityrelativetotheirabilitytocarrylateralandcompressive loadswhichwouldbeimposedunderdesignbasisseismicloadcases.Theicecondenser designbasis,asdescribed intheFSAR,statesthattheicecondenser internalstructures, including icebaskets,aredesignedtobecapableofwithstanding variousloadcombinations including deadweight (D)plusoperating basisearthquake (OBE)loads,D+designbasisearthquake (DBE)loads,D+designbasisaccident(DBA)loads,andD+DBE+DBAloads.Asnotedpreviously, ascopingtestofasampledamagedbasketwithtestloadslessthanD+OBEresultedinafailureofthebasketwithplasticdeformation.

Therefore, theexistence ofdamagedbasketswhichwereunabletowithstand designloadsrepresented acondition outsidethedesignbasis.Asnotedpreviously, itisestimated thatapproximately 25basketsintheUnit1icecondenser and45basketsintheUnit2icecondenser exhibitsimilardamage.Basketswithdentsareestimated tobeasimilarquantityofbaskets,withafinalquantification tobemadefollowing inspections duringthecurrentoutages.Withregardtooperability, bothunit'sT/Srequireperiodicinspections oficebasketsfor"detrimental damage",todemonstrate operability.'hile theterm"detrimental damage"hasnotbeenformallydefined,damage,whichresultsinabasket'sinability tocarrydesignloads,isconsidered detrimental.

Therefore, theexistence ofthesedamagedicebasketsisconsidered torepresent aninoperable condition foreachicecondenser.

Withregardtofunctionality, icebasketswithfoldswillhavereducedstructural capability relativetotheirabilitytocarrylateralandcompressive loads,whichwouldbeimposedunderdesignbasisseismicloadcases.Thepotential forcontinued icebasketfailureunderdesignbasisseismicloadingconditions atthefoldisafunctionofthesizeofthedamage,andtheweightoftheiceinthebasketsectionsabovethedamagearea.Itmaybepostulated thatthedisplacement ofthedamagedbasketsectionunderaseismicloadingmaybeenoughtocausethebaskettodisplacelaterally intoanadjacenticebasketcolumn.However,sincebasketsectionswithfoldshavebeenshowntohavesubstantial strengthasdemonstrated inaforementioned testing(whichboundsdents,whereplasticdeformation hasnotoccurred),

andsincesignificant energywouldbedissipated inthedeformation oftheicebasketsheetmetalsectionandenclosedice,itisexpectedthaticebasketstructural integrity willbemaintained, soastoprecludesignificant collateral icebasketdamageandflowpassagegeometrydegradation.

Becauseofthisandthefactthateachicebasketcolumnissupported laterally everysixfeetinelevation byastructural latticeframegrid,itishighlyimprobable thatasignificant dominotypefailurewouldoccurwherethedamagedbasketcollapses intoanadjacentbasketandsoforth.Therefore, icebasketswithdentsandfoldsareconsidered tobeoutofthedesignbasis,andinoperable fromthestandpoint ofcompliance withthesurveillance requirement relatedtodetrimental damage,however,thedamagedoesnotresultintheicecondenser beingincapable ofperforming itsdesignfunctiontopreventcontainment overpressure following ahighenergylinebreakinsidecontainment.

HRCFORM366A.S.NUCLEARREGULATORY COMMISSION LICENSEEEVENTCONTINUATION OVEDBYOMBiiO.315DD104EXPIRES5/31/95STIMATEDBURDENPERRESPOHSETOCOMPLYllITHTHISINFORMATION COLLECTION REQUEST:50.0NRS.FORliARDCOMMEHTSREGARDING BURDEHESTIMATETOTHEINFORMATION ANDRECORDSMANAGEMENT BRANCH(HNBB7714),U.S.NUCLEARREGULATORY COHHISSION, WASHINGTON, DC20555-0001, ANDTOTHEPAPERNORK REDUCTION PROJECT(31500104),OFFICEOFHANAG'EMERY ANDBUDGETNASNIHGTON DC20503.FACILITYNAME1CookNuclearPlant-Unit1TEXTufcorespacelsrequired.

useadditional NRCFore36&4's)Ill)DOCKETNUMBER250-315YEAR98LERNUMBER&SEQUEHTIAL REVISION008-01PAGE36OF6asoevecoFurtherevaluation ofdamagetotheicebasketsanditspotential impactontheabilityoftheicecondenser toperformitsdesignfunctionwillbecompleted, asnecessary, following thethawofeachunit'sicecondenser.

Bothunit'sicecondensers arebeingcompletely thawedtoallowinspection ofthe1944icebasketsineachunit,forthepurposeofidentifying andcorrecting, byrepairorreplacement, damagedbaskets.Adefinition of"detrimental damage"isbeingdeveloped toserveasagageforjudgingwhetherobservedicebasketdamageneedsrepair.Thisdefinition willbeincorporated intodesignbasisdocuments andprocedures forsurveillance oftheicecondenser.

Damagebeyondthethreshold ofdetrimental damagewillberepairedorreplaced.

Theseactionswillbecompleted priortostartupforeachunit.Afterthethawofeachunit'sicecondenser, athoroughinspection oficebasketswillbeperformed.

Althoughtheseinspection activities willlikelyresultintheidentification ofadditional damagedbaskets,thetypesofbasketdamageunderconsideration arenotexpectedtochange.Thiscondition isapplicable tobothunits.Responsibility foroversight ofproduction work-maintenance andsurveillance activities

-isbeingtransferred fromtheEngineering totheMaintenance department.

Thiswillallowpersonnel skilledinsupervising production workerstoprovideoversight fortheicecondenser laborforce,including contractlabor,ifusedinthefuture.Theprocedures usedtoguidemaintenance andsurveillance activities fortheicecondenser arebeingupgradedandrewritten forusewithintheMaintenance department.

Theupgradedprocedures willcontainimprovedguidanceonmaintenance andsurveillance activities toprecludefuturedamagetoicebaskets.Thetrainingprogramforicecondenser workersisbeingupgraded.

Theupgradedtrainingwillincludeimprovedguidanceonpropertechniques toavoidbasketdamage.Icecondenser maintenance procedures arebeingrevisedtorequireinspection ofbasketsemptiedformaintenance priortorefilling duringfutureoutages.Thebasketinspection willspecificaliy includeprovisions foridentifying icebasketdamageandcorrecting damagethatexceedsthethreshold ofdetrimental damage.Thesepreventive actionswillbeinplacepriortocommencing relevanticecondenser activities duringthecurrentoutagesoneachunit.FailedCmonenldeficaionNotapplicable eouaEveNone