ML17334B684

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Forwards Addl Info Re CAL Item 3,involving Ability of Plant to Be Cooled Down in 36 H,Per NRC 980109-23 Insp
ML17334B684
Person / Time
Site: Cook  American Electric Power icon.png
Issue date: 01/29/1998
From: FITZPATRICK E
INDIANA MICHIGAN POWER CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
AEP:NRC:1260G8, CAL, NUDOCS 9802120308
Download: ML17334B684 (9)


Text

CATEGORY1~REGULATOR INFORMATION DISTRIBUTIO?PKYSTEM (RIDS)ACCESSION NBR:9802120308 DOC.DATE:

98/01/29NOTARIZED:

NOFACIL'50-315 DonaldC.CookNuclearPowerPlant,Unit1,IndianaM650-316'onald C.CookNuclearPowerPlant,Unit2,Indiana,M AUTH.NAMEAUTHORAFFILIATION FITZPATRICK,E.E IndianaMichiganPowerCo.RECIP.NAME RECIPIENT AFFILIATION DocumentControlBranch(Document ControlDesk)

SUBJECT:

Forwardsconfirmatory actionresporise validation inspforRAIreitem3,"36HourCooldown.

DOCKET0500031505000316DISTRIBUTION CODE:IE36DCOPIESRECEIVED:LTR iENCLJSTEE-.TITLE:Immediate/Confirmatory ActionLtr(50Dkt-Other ThanEmergency PreparNOTES:RECIPIENT IDCODE/NAME PD3-3PDCOPIESRECIPIENT LTTRENCLIDCODE/NAME' 1THICKMAN<J COPIESLTTRENCL11EG0INTERNA:FILECETEIBEXTERNAL:

NOAC01111111NRR/DRPM/PECB NRCPDR11RDENNOTETOALL"RIDS"RECIPIENTS:

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

LTTR7ENCL7 t*>L$t~

IndianaMichiganPowerCompany500CircleDriveBuchanan, Ml491071395INSlANAN1CNESSlNPQWMJanuary29,1998AEP:NRC:1260G8 DocketNos.:50-31550-316U.S.NuclearRegulatory Commission ATTN:DocumentControlDeskMailStop0-Pl-17Washington, D.C.20555-0001 Gentlemen:

DonaldC.CookNuclearPlantUnits1and2CONFIRMATORY ACTIONRESPONSEVALIDATION INSPECTION RESPONSETOREQUESTFORADDITIONAL INFORMATION REGARDING ITEM3,"36HOURCOOLDOWN" DuringthetimeperiodJanuary9,1998,throughJanuary23,1998,theNRCconducted aconfirmatory actionletter(CAL)followupinspection.

Duringtheexitmeetingfortheinspection, onJanuary26,1998,wewererequested todocketadditional information regarding CALitem3,involving theabilityoftheplanttobecooleddownin36hours.Attachment 1tothislettercontainstheinformation requested.

Attachment 2containsaflowchartdepicting theinformation inattachment 1.Sincerely, EF~pm'.E.Fitzpatrick VicePresident

/vlbAttachments J.A.AbramsonA.B.BeachMDEQ-DWfcRPDNRCResidentInspector J.R.Sampson9802i20308 980i29PDRADQCK050003i5)PDRJj.M~~W+IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

'

ATTACHMENT 1TOAEP:NRC:1260G8 ADDITIONAL INFORMATION RELATEDTO36HOURCOOLDOHNCONFIRMATORY ACTIONLETTERITEM3 Attachment 1toAEP:NRC:1260G8 Page1Introduction Item3oftheconfirmatory actionletter(CAL)dealtspecifically withthe36hourcooldown.

DuringtheCALvalidation inspection, severalconcernswereraisedbytheNRCrelatingtothisissue.Thisletterisprovidedtoassistwiththecharacterization of'hoseconcerns.

FromAugust4,1997,throughSeptember 12,1997,theNRCconducted anarchitect engineering (AE)inspection atCookNuclearPlant.Duringthatinspection, severaldeficiencies wereidentified relatedtothecomponent coolingwater(CCW)system.Twosuchdeficiencies were:the36hourcooldownanalysiscompleted byWestinghouse forCookNuclearPlantcontained errors,andnomaximumcoolingflowlimitsexistedtoprotectthecomponents cooledbyCCWfromhigh,potentially damagingflowrates.Subsequently, concurrent effortswereundertaken tocorrectthecooldownanalysisandestablish maximumflowlimits.OnAugust29,1997,condition report(CR)97-2378waswrittentocapturetheAEinspector's concernthatmaximumflowlimitsfortheCCWsystemdidnotexist.Thecondition reportinvestigation wascompleted onDecember20,1997.Aspartofthatinvestigation, technical reviewswerecompleted thatestablished anupperflowlimitforeachofthecomponents cooledbytheCCWsystem.Acommitment wasmadeinthatCRresponsetoincorporate theupperflowlimitsintotheupdatedfinalsafetyanalysisreport(UFSAR).Theduedateforthatcommitment isApril1999.TheApril1999datecorresponds tothenextplannedrevisionoftheUFSAR.AspartoftheprocessofupdatingtheUFSAR,a10CFR50.59evaluation isperformed.

OnSeptember 19,1997,theNRCissuedaCALtoCookNuclearPlant.TheCALdetailedeightspecificitemsthatrequireresolution priortorestart,oneofwhichisthe36hourcooldownissue.InourletterAEP:NRC:1260G3, datedDecember2,1997,weprovidedourCALresponsetotheNRC.FromJanuary9,1998,toJanuary23,1998,theNRCconducted aCALvalidation inspection toreviewandverifytheCALresponse.

Discussion Duringthevalidation inspection, theNRCreviewedCALItem3,36hourcooldown.

Thereviewwastwo-fold.

First,theNRCreviewedtheactualplantcooldowncalculation completed byWestinghouse, aswellasthesupporting documentation thathadbeencompiledbybothusandWestinghouse.

Thatdocumentation includedWestinghouse's safetyevaluation checklist(SECL)97-189,andour10CFR50.59evaluation completed forthe36hourcooldown.

Itwasdetermined that,duringa36hourcooldown, theCCWsupplytemperature mayexceedthepreviously analyzed95~Fandreachamaximumof120~F.Aspartofdesignchange12-DCP-855, thenecessary technical reviewsandplantmodifications werecompleted toallowtheCCW Attachment 1toAEP:NRC:1260GB Page2supplytemperature toreach1204F.Inthisletter,the10CFR50.59evaluation thatwascompleted for12-DCP-855 isreferredtoasthe36hourcooldownsafetyevaluation.

Uponreviewing theWestinghouse cooldowncalculation, theNRCquestioned twooftheinputsusedintheanalysis.

OnequestiondealtwiththetotalCCWflow.Intheanalysis, thetotalCCWflowratewas8,000gpm(i.e.,4.0E6lb./hr.).

Thisvaluewastakendirectlyfromtable9.5-3oftheUFSAR.TheNRCexpressed concernthattherewasnomarginbetweentheanalysisinputvalueandtheUFSARvalue.Toaddresstheconcern,a10CFR50.59evaluation wasexpedited torevisetheUFSARtoallow9,000gpmoftotalCCWflowthroughasingleCCWheatexchanger.

Asdiscussed above,theneedforthis10CFR50.59reviewhadalreadybeenrecognized andcommitted toaspartoftheinvestigation ofCR97-2378.Itisimportant torecognize thattheanalysisinputof8,000gpmwastakendirectlyfromtheUFSARandthatthe9,000gpmvalueistobeaddedtotheUFSARtoshowthatmarginexistsinthecooldownanalysis.

AnotherquestiondealtwiththeCCWcoolingflowtotheresidualheatremoval(RHR)heatexchangers.

Thisvaluewas5,000gpminthecooldownanalysis.

TheNRCinquiredwhetherinstrument uncertainty hadbeenappliedtotheflowvalue.TheNRCcommented thatatotherplantsitwasnotuncommontoseeaflowuncertainty ontheorderof1,000gpm.Toaddresstheconcern,weprovidedtheNRCwithinformation showingthattheuncertainty intheflowindication loopwasonlyontheorderofp200gpm.Additionally, theCCWflowtotheRHRheatexchanger isonourcriticalparameters list.Perapreviouscommitment madetotheNRCinourletterAEP:NRC:1260G3, datedDecember2,1997,instrument uncertainty willbeincorporated intotheoperating procedures foreachvalueonthecriticalparameters list.Thiscommitment hasaduedateofDecember31,1998.Thus,theissueaboutuncertainty intheCCWcoolingflowratetotheRHRheatexchangers isalreadyscheduled tobeaddressed underapxeviouscommitment.

totheNRC.Inadditiontoreviewing theactualcooldowncalculation, theNRCalsoreviewedthesupporting documentation.

Includedinthatdocumentation wasSECL97-189completed byWestinghouse tosupportoperation oftheCCWsystemat.theelevatedsupplytemperature of1204F.IntheirSECL,Westinghouse statedthecontrolvalve.regulating theCCWflowtotheletdownheatexchanger willgofullopenduringa36hourcooldown.

TheNRCnotedthatWestinghouse assumed,withthevalvefullopen,atotalCCWflowof1,000gpmthroughtheletdownheatexchanger.

Theinspector pointedoutthattable9.5-2oftheUFSARliststhedesignCCWflowtotheletdownheatexchanger as984gpmandquestioned whytheapparentdiscrepancy wasnotcalledoutinthesafetyreview.Thefollowing explanation wasprovided.

Theactualdesigncoolingflowratefortheletdownheatexchanger is492,000lb./hr.-amassflowrate,notavolumetric flowrate.Thisisshownintable9.2-3oftheUFSAR.Theflowrateof984gpm,asshownintable9.5-2oftheUFSAR,isthevolumetric flowratethatcorresponds to492,000lb./hr.atstandardconditions.

Theflowrateof1,000gpm,asshownintheSECL,isthevolumetric flowratethatcorresponds to492,000lb./hr.attheCCWreturntemperature expectedduringa36hourcooldown.

Thus,thevolumetric flowratesof984gpmand1,000gpmarebothcorrectastheyarebothderivedfromthedesignmassflowratespecified fortheletdownheatexchanger.

Attachment 1toAEP:NRC:1260G8 Page3Asafollowupquestiontotheoneabove,theNRCaskedhowmuchCCWflowisexpectedtopassthroughtheletdownheatexchanger withthecontrolvalvefullopen.Apreliminary calculation determined withthecontrolvalvefullopen,approximately 1,400gpmwouldpassthroughtheletdownheatexchanger.

TheNRCfurtherquestioned whytheflowrate,whichisgreaterthanthevaluelistedintheUFSAR,wasnotevaluated inthe36hourcooldownsafetyevaluation.

Toaddresstheimmediate concern,a10CFR50.59evaluation wasexpedited toevaluatetwicethedesigncoolingflowratethroughtheletdownheatexchanger (approximately 2,000gpm).Asdiscussed above,theneedforthis10CFR50.59reviewhadalreadybeenrecognized andcommitted toaspartoftheinvestigation ofCR97-2378.Althoughtheletdownheatexchanger coolingflowrateof1,400gpmwasnotspecifically addressed inthe36hourcooldownsafetyreview,aboundinganalysishadbeencompleted andacommitment torevisetheUFSARalreadyexisted.Itisimportant torecognize that,althoughtheincreased CCWflowratetotheletdownheatexchanger isaconsequence ofthehigherCCWsupplytemperature, itisnotaninputinthecooldownanalysis.

ATTACHMENT 2TOAEP:NRC:1280G8 FLOWCHARTDEPICTING INFORMATION PROVIDEDINATTACHMENT 1

hccacbsienc 2soAEP/NRCI126008

.QUESTION:

Thecakuhtion assumes5000gpmofCCWcoohngflowtotheRHRheatexchanger.

Washstrument uncertainty appfied?ANSWER:TheCCWihwtotheRHRheatexchangers isonthecriticalparameters gsLAllprocedures whichreference the5000gpmusedintheanalystswfllberevisedtoaccountforinstrument uncertainty.

Thislsagbbalcomnitment totheNRCwhichisduebytheendof1998.rNRC/AE,INSPECTION August-September 1997CALITEM¹336HourCooldownIIINRCInspector ReviewedWestinghouse PlantCooldownAnalysisNRCInspector ReviewedWestinghouse SECLandOurSafetyEvaluation QUESllON; ThecooldownanalysisassumesatotalCOWlhwof8000gpm.TheFSARaflawsatotalCCWflawof809gpmthroughtheCOWheatexchanger.

Wiryistherenomarginbetweentheosculation hpulandthephotdesignbasis?QUESTION:

Westinghouse statedthattheCOWcontrolvalvefortheletdownheatexchanger wglgofuflopen.UsingaCCWflawrateof1000gpmtotheletdownheatexchanger, theycahuhtedthemagnumletdowntemperature.

TheFSARstatesthattheCCWIhwtotheletdownheatexchanger Is984gpssWhywasnlthisaddressed inlhesafetyevahation?

IIIIIIIIIIIIIIIRESOLUTION:

The50.59reviewtoaflaw9000gpmthroughtheCCWheatexchanger wasexpedited.

(Comphted 1/23/98)RESOLUTION:

AsshawnhtheFSAR,thedesignflawfortheletdownheatexchanger is492,000ib/hr.Thisisequfiratent to984gprnat76'Fand1000gpmat120'F.Westinghouse correcfly used492,000Ib/hrtocahutateIhetemperature.

'0Subsequent tothehspection, atechnkstreviewwascompleted todetermine amaximumaflowabhcaofingihwrateforeachcomponent servedbyCCW.(CR97-2378)Themaxhxrmaflawabfe ihwthroughtheCCWheatexchanger is9000gpm.Completed 12/2N97,Themaximumaflawable llawthroughcooflngfhwthroughtheletdownheatexchanger Istwicedesign(l.e.984,000lb/br).ted12/20/97.

ApartFconvnitment wasmadeIncorxfitian report97-2378tohcorporate themaximumflawfimitshtotheFSAILCommitment made:11/23I97Commitment due:Apnl1999QUESTION:

Ifthecontrolvalvedoesgofuflopen,whatwiflbetheCCWfhwratetotheletdownheatexchanger?

ANSWERWiththecontrolvalvefullopen,theCCWflowwgbeapproxhnatety 1400gpm..This IsgreaterthanthedesignfhwrateshownhtheFSAILRESOLUTION:

The50.59reviewtoaihwtwicedesignflawratethroughtheletdownheatexchanger wasexpefited.

(Completed 1/23lg