ML082050360
| ML082050360 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 07/22/2008 |
| From: | Hartz L Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 08-0388 | |
| Download: ML082050360 (9) | |
Text
10CFR50.90 VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 July22"2008U.S.NuclearRegulatoryCommissionAttention:DocumentControlDeskWashington,D.C.20555SerialNo.08-0388 NL&OS/ETS RODocketNos.50-338/339LicenseNos.NPF-4/7 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
NORTH ANNA POWERSTATIONUNITS1AND2 PROPOSED LICENSE AMENDMENT REQUEST REQUEST FOR ADDITIONAL INFORMATION ONE-TIME RISK-INFORMED EXTENSIONTOTHE COMPLETION TIMEFOREDGFUELOIL STORAGETANKRECOATINGIna December17,2007letter(SerialNo.07-0803),Dominionrequestedamendments,intheformofchangestotheTechnicalSpecificationstoFacilityOperatingLicenseNumbersNPF-4andNPF-7forNorthAnnaPowerStationUnits1and2.Theproposedchangewillpermitaone-timeextended14-daycompletiontimeforeachofthetwoundergrounddieselfueloilstoragetankstopermitremovalofthecurrentcoatingandrecoatingofthetanksinpreparationforuseofultra-lowsulfurdiesel(ULSD)fueloil.InaJune24,2008lettertheNRCrequestedadditionalinformationtocompletethereviewoftheproposedTechnical Specification.TheinformationprovidedinthisletterdoesnotaffecttheconclusionofthesignificanthazardsconsiderationdiscussionprovidedintheDecember17,2007Dominionletter(SerialNo.07-0803).Shouldyouhaveanyquestionsorrequireadditionalinformation,pleasecontactMr.ThomasShaubat(804)273-2763.Verytrulyyours,LeslieN.HartzVicePresident-uclearSupportServices COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO VICKI L.HULL Notary PuIIIc commonwealth of""WInIO 1-"2 My CommlllionMay 11.201.Theforegoing document was acknowledgedbeforeme,inandfortheCountyand Commonwealthaforesaid,todaybyLeslieN.Hartz,whoisVice President-NuclearSupportService,ofVirginia ElectricandPowerCompany.Shehasaffirmedbeforemethatsheisdulyauthorizedto executeandfiletheforegoing documentinbehalfofthatCompany,andthatthe statementsinthe documentaretruetothebestofher knowledgeandbelief.
Il dAcknowledgedbeforemethis
- L-day of,2008.My Commiesion Expiras
- 5/3/L(o.I 7 (,i.'/5,'kbNotaryPublic SerialNo.08-0388DocketNos.
50-338/339RAI-EDGFOStorageTank CompletionTimeExtensionPage2of2 Commitmentsmadeinthisletter:Dominioncommitstore-reviewthePRAmodelconfigurationcontroldatabasepriortothe implementationoftheproposedCompletionTimeextensiontoreconfirmthattheaboveevaluationremainsvalid.
AttachmentResponsetoRequestforAdditionalInformation-ExtendedCompletionTimeforEDGFuelOilStorageTankRecoatingcc:U.S.NuclearRegulatoryCommissionRegionIISamNunnAtlantaFederalCenter61ForsythStreet,SWSuite23T85Atlanta,Georgia30303Mr.J.E.Reasor,Jr.OldDominionElectricCooperativeInnsbrookCorporateCenter4201DominionBlvd.Suite300GlenAllen,Virginia23060StateHealth Commissioner Virginia DepartmentofHealthJamesMadisonBuilding-i h floor109 Governor StreetSuite730Richmond,Virginia23219NRCSeniorResidentInspectorNorthAnnaPowerStationMr.S.P.LingamNRCProjectManagerU.S.NuclearRegulatoryCommissionOneWhiteFlintNorthMailStop 0-8 G9A11555RockvillePikeRockville,Maryland20852 SerialNo.08-0388 Docket Nos.50-338/339ResponsetoRAIforEDGFOExtendedCT Attachment Request for Additional Information Extended Completion TimeForEDGFuelOil Storage Tank RecoatingNorthAnna Power StationUnits1and2 Virginia Electric and Power Company (Dominion)
SerialNo.08-0388DocketNos.
50-338/339 BackgroundInaDecember17,2007letter(SerialNo.07-0803),Dominionrequestedamendments,intheformofchangestotheTechnicalSpecificationstoFacilityOperatingLicenseNumbersNPF-4andNPF-7forNorthAnnaPowerStationUnits1and2.Theproposedchangewillpermitaone-timeextended14-dayCompletion Time(CT)foreachofthetwoundergrounddieselfueloilstoragetankstopermitremovalofthecurrentcoatingandrecoatingofthetanksinpreparationforuseofultra-lowsulfurdiesel(ULSD)fueloil.InaJune24,2008lettertheNRCrequestedadditionalinformationtocompletethereviewoftheproposedTechnicalSpecification.NRCQuestion1Thelicensee'ssubmittalidentifiedthatsignificantfindingsandobservations(F&Os)from the 2001peerreviewhaveeitherbeen resolvedorfoundtohavenoimpactontheproposedTechnicalSpecificationchange.Thelicenseeisrequestedtoidentifyandprovideitsdispositionofthe unresolvedsignificantF&Oswithregardtothisspecific application.
Dominion responseTheopenF&Osfromthe2001 peerreviewwerereviewedtoidentifywhich oftheitemshavethe potentialtoimpacttheriskinsightsfortheproposedTechnicalSpecificationchange.Therearenoopenlevelitems.None oftheopen"B"levelF&OswereidentifiedtoimpacttheproposedTechnicalSpecificationchangeonthebasisthattheopenF&Osdonotaffectaccidentsequenceswheretheundergroundtanksarecredited (Loss of Offsite Powereventswhicharenotrecoveredwithinthefirstfewhours).Table 0-2belowprovidesadditionalinformationoneachopenLevel"B" F&O.NRCQuestion2Thelicenseeisrequestedtoconfirmthattherearenooutstanding(i.e.,notincorporatedintothebaselinePRAmodel)plant modifications,procedurechanges,orotheroutstandingdeficienciesforthecurrentPRAmodelsuchthatitreasonablyreflectstheas-builtas-operatedplant.Further,sincethistemporarychangeisnotdate-limited,provideacommitmenttoreviewthePRAresultspriortoimplementationoftheTSchangetoreconfirmthisitem.DominionresponseDominionPRAmodelconfigurationcontrolprocessrequiresplantchanges(plantmodifications,procedurechangesetc.)tobecollectedandreviewedandthosewhich could potentiallyaffectthePRAmodeltobeenteredintothePRAmodelconfigurationcontroldatabase.Additionally,anestimate oftheexpectedimpact of the proposedmodel/documentationmodificationsontherelevantmodelismadeandthe implementations oftheproposedchangeintothemodelareprioritized.Page1 SerialNo.08-0388 Docket Nos.50-338/339 The proposedmodelchangesinthePRAmodelconfigurationcontroldatabasewerereviewedtoidentifyany proposedchangethatmayimpacttheriskinsightsforthe proposedUGFOSTCTextension.Thesechangesarecategorized as follows: Administrative DocumentationTherewerenoAdministrativeordocumentationchangesrelatedtotheUGFOST.
Model logicNochanges orcorrectionstomodellogicwerefoundrelatedtotheUGFOST.Thereareseveralopenitemsrequestingimprovedmodelingbutthesewilltypically lower the estimated plantvulnerabilityto a loss ofUGFOSTeventandwillnotadverselyimpact the proposedTSchange.Plant/model components No model/plantcomponentchangeswerefoundrelatedtotheUGFOST.
Investigation/EvaluationTherewerenoquestionstoinvestigateorevaluatefortheUGFOST.Thereareseveralopenitemsrequestingimprovedmodelingbutthesewilltypicallylowertheestimated plantvulnerabilityandwillnotadverselyimpactthe proposedTSchange.The consequentialLOOPisunderevaluationformodeling.However,giventhesignificantmargininthefigures ofmerit(CDFandLERF)fortheproposedCTcomparedwiththeregulatorycriteriaforthelowrisk-significancethreshold, as well astheconservative non-modeling ofthefueloiltankcrosstie valve,itis judgedthatthe potential inclusion oftheconsequentialLOOPwillnotchangethepertinentriskinsights.
Self Assessments SelfAssessmentsdidnotidentifyanyconcerns orenhancementsrelevanttothe UGFOST.Operating Experience reviewsTherewerenochangesidentifiedfromOEreviewfortheUGFOST.ThereisanoutstandingitemtoupdatingtheLOOPfrequencybuttheanticipatedimpactissmall.TheLOOPfrequencyalreadyincludesthenortheastU.S.blackoutduring August 2003.Improvements/EnhancementsNoimprovementsorenhancementswereidentified.Dominioncommitstore-reviewthePRAmodelconfigurationcontroldatabase prior totheimplementation oftheproposedCTextensiontoreconfirmthattheaboveevaluationremains valid.Page 2 SerialNo.08-0388 Docket Nos.50-338/339 NRC Question 3Thelicensee'ssubmittaldidnotdiscussmodeltruncationapplicabletoitsanalysis.Thelicenseeisrequestedtoidentifyandjustifythetruncationlevelusedforthisapplication.
Dominion responseTheNorthAnnaaveragemaintenancemodeltruncationissetto 5E-12andyields a CDF of5.4E-6/year.Theunavailability of asingleUGFOSTresultsin aCDFincrease of lessthan6E-7/yr,morethanfiveorders ofmagnitudeabovetruncation.Thismarginissufficientlyhightoensurethatthestandardtruncationisadequate.Additionally,itis judgedthatthemodelresultsarestableattheabovementionedtruncationvalue.
NRC Question 4Section5ofAttachment2ofthelicensee'ssubmittal(December17,2007)identifiessensitivitycalculationsperformedwhichpurportedlysupporttheriskanalysisconclusions,however,thespecificsofthesecalculationsarenotdiscussed.Thelicenseeisrequestedtoidentifyanddiscusstheresultsofthesensitivitycalculationsperformed.
Dominion responseThesesensitivitycalculationshavebeenredonetosupporttheriskanalysisusingthe presentNorthAnnamodel.Whenintegratedoverthetime oftheproposedCT,thechangeinCoreDamageProbabilityisstillbelowtheRG 1.174andRG 1.177limits.Thetablebelowpresentsthe results.TableD-1 SensitivityCalculationsResults Case CDFChanaeinCDFfrombaseBase(eva.maintenance) 5.365 E-06/vrBase(avg.maintenance)with1-EG-TK-2A5.909 E-06/yr 5.44E-7/yr failed TK-2A unavailable and failure probability ofTK-5.968 E-06/yr 6.03E-7/yr 2B increased to 95%upper limit TK-2A unavailable and failure probability of TK-6.103 E-06/yr 7.38E-7/yr 2B increased by a factor of 10Page3 SerialNo.08-0388 Docket Nos.50-338/339TheopenF&OswereevaluatedagainsttheproposedCTfortheUndergroundFuelOil Storage Tank.Theresultsaresummarizedinthetablebelow.TheUGFOSTchangeispotentiallyapplicableduringanyLoss ofOffsitePowereventthatlasts longerthanthetimerequiredtoemptythedaytanksfortheEmergencyDieselGenerators.TheFIOswerereviewedfor potentialimpactonlonger-durationLOOPmitigation.
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NIsi.Observation Summary Applicability OBSERVATION 10: AS-Several observationswereidentifiedThesefindingsdonot negatively 08/Element AS IregardingtheeventtreeforA lWSatimpactthe accident sequences Sub-element 9 greaterthan40%power.
where UGFOSTsarecredited.(Related Sub-elements:
TH-6, ST-4)OBSERVATION 10: OE-IPE AppendixE,InternalFlooding,pageThese findingsdonot negatively 01/Element DE I E-17 establishes511,000gallons(44"impactthe accident sequences Sub-element 3abovetheAuxiliaryBuildingbasementwhere UGFOSTsarecredited.(Related Sub-elements:floorelevation)astheminimumvolume OE-10)[Also see related of waterthatcouldbeallowedonthisF&OOE-02]elevationbeforeanyflooddamageto equipmentissustained,assumingthatthelevelequalizesacrossthewhole floor.OBSERVATlON10:OE-Unit2cross-tiesfromChargingandThesefindingsdonot negatively 04/Element DE I Component Cooling Waterwerenotimpactthe accident sequences Sub-element 10consideredinthefloodinganalysis,where UGFOSTsarecredited.(Related Sub-elements:
AppendixEoftheIPE.SY-5,SY-10, MU-4)OBSERVATION 10: ST-TheNorthAnnaISLOCA frequencyisThesefindingsdonot negatively 01/Element ST Ibasedontheevaluationperformedinimpactthe accident sequences Sub-element 9 NUREG-1150forSurry.where UGFOSTsarecredited.
OBSERVATION 10: ST-TheA lWS analysis documentationdoesThesefindingsdonot negatively 02/ElementST Inotclearlyrelatetheanalysisperformed impact the accident sequences Sub-element 13 Alsotothe corresponding requirementsofthe where UGFOSTsarecredited.seeF&OST-01 and AS-genericanalysisreferredto.
08.Page4 Serial No.08-0388 Docket Nos.50-338/339 TableD"2 FACT/OBSERVAT1ONREGARDINGPRA TEe Observation Summary Applicability OBSERVATION10:QU-The limitationsassociatedwithPRAThisisa documentationF&O.As 02/Element QU I Sub-resultsshouldbeclearlystatedinthepartoftheanalysisin support of element 7 (RelatedPRAModel Quantification calculationtheproposed AOTextension,the Sub-elements:
QU-34,notes(i.e.,SM-1274,Revision0),sothat modeling limitations were MU-10)ALSO SEE their relative importance to specificconsidered.ThesemodelingF&OQU-09.applicationscanbe determinedforeach limitationsdidnothaveanegative application.impactonthe proposed UGFOST AOTextension.Forexample,onemodelinglimitation,non-modelingofthe crosstie valves between UGFOSTs, wasidentifiedtohaveapositiveimpact(i.e.,would decrease thedeltarisk).
OBSERVATION10:L2-TheNorthAnnaearly containmentfailureThese findingsdonot negatively 02/Element L2 I conditional probabilityisbasedontheimpactthe accident sequences Sub-element 81992IPEanalysiswhichisbasedonwhere UGFOSTsarecredited.(Related Sub-elements:
NUREG-1150assessments.Thisis L2-10)conservativeinlightofcurrentknowledge of containmentresponseandaccident phenomenology.
OBSERVATION10:L2-TheNorthAnnaearly containmentfailureThesefindingsdonot negatively 03/Element L2 I conditional probability assessmentdoesimpactthe accident sequences Sub-element 9notincludeconsiderationof operator where UGFOSTsarecredited.(Related Sub-elements:actionsthatmayinfluenceLERFbutdoL2-12,L2-25, MU-4)notimpacttheCDF.Thatis,only operatoractionsthatimpacttheCDFarecurrentlymodeledinthePRA.
OBSERVATION 10: L2-Thereisnobasisinthe documentationTheLERFmodelhasbeen 04/Element L2 IfortheLERFdefinition.The assignmentrevisedandits documentation Sub-element 22 (RelatedofSourceTerm CategoriestoLERFisdrafted.Allreview comments Sub-elements:L2-1)documentedinSM-1090(thisisfor with technical significance haveSurry,butitwasusedasasurrogateforbeenresolved.LOOPeventsdoNorthAnna),butthebasisforthenotinvolve containment bypass assignmentismissing.andare thereforenotLERFlimiting;thusnoimpactupontheproposedTSchangeisexpected.Page5 ObservationOBSERVATIONID:L2-06/Element L2 I Sub-element 26 (Related Sub-elements:
L2-28)OBSERVATlONID:L2-09/Element L2 I Sub-element 22OBSERVATIONID:L2-10/Element L2 I Sub-element 22 (Related Sub-elements:
ST-9)SummaryThemostrecentLERFmodelforNorthAnnacouldnotbelocated.TheLERFmodelforSurry(SM-1090)wasmadeavailablebyDominionwiththeguidancethattheNorthAnnamodelisidenticalto Surry.AllSGTReventsandall InterfacingsystemLOCAevents without pool scrubbinggototheLERFcategory.TheLERFis dominatedbySGTRevents.ThereviewersnotedthattheinterfacingsystemLOCAanalysisusesatwoinchpipesizeasascreeningcriterionforbypasssequences,andbelievethatthisistoohigh.Page6 Serial No.08-0388 Docket Nos.50-338/339 ApplicabilityTheLERFmodelhasbeenrevisedandits documentationdrafted.Allreview commentswithtechnical significance havebeenresolved.LOOPeventsdonotinvolve containment bypassandare thereforenotLERFlimiting;thusno impactupontheproposedTSchangeisexpected.
These findingsdonot negatively impact the accident sequences where UGFOSTsarecredited.
These findingsdonot negatively impact the accident sequences where UGFOSTsarecredited.