ML081790666

Proposed License Amendment Request for Five-Year Containment Type a Test Extension, Request for Additional Information

ML081790666
Person / Time
Site:	Surry
Issue date:	06/27/2008
From:	Gerald Bichof Virginia Electric & Power Co (VEPCO)
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
08-0326
Download: ML081790666 (9)

Text

VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 June 27, 200810CFR 50.90U.S.NuclearRegulatoryCommissionATTN:DocumentControlDeskWashington,D.C.20555 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATIONUNIT2 PROPOSED LICENSE AMENDMENT REQUEST FIVE-YEAR CONTAINMENTTYPEA TEST EXTENSION REQUEST FOR ADDITIONAL INFORMATION (RAilSerialNo.NLOS/ETSDocketNo.LicenseNo.

08-0326 R1 50-281 DPR-37ByletterdatedDecember17,2007(SerialNo.07-0802),VirginiaElectricandPowerCompany(Dominion)requestedanamendment,intheformofachangetotheTechnical Specifications(TS)toFacilityOperatingLicenseNumberDPR-37forSurryPowerStationUnit2.Theproposedchangewillpermitaone-timefive-yearexceptiontotheten(10)yearfrequencyoftheperformance-basedleakageratetestingprogramforTypeAtestsasrequiredbyRegulatoryGuide(RG)1.163.Thisone-timeexceptiontotherequirementof HG1.163willallowthenextTypeAtesttobeperformednolaterthanOctober26,2015.InaMarch20,2008letter,theNRCstaffrequestedadditionalinformationregardingcontainmenttestingandinspectionhistory,aswellasthepenetrationtestandinspectionscheduleduringthefive-yearextendedperiod.Therequestedinformationregardingthe containmenttestandinspectionswasprovidedinaletterdatedApril24,2008(SerialNo.08-0176).InaletterdatedMay29,2008,theNRCrequestedadditionalinformationregardingtheriskassessmentperformedtosupportthe five-yearextension.TheattachmenttothisletterprovidestheinformationrequestedbytheNRCstaff.Theinformationprovidedinthisletterdoesnotaffecttheconclusionofthe significant hazardsconsiderationdiscussionprovidedintheDecember17,2007Dominionletter(SerialNo.07-0802).

SerialNo.08-0326DocketNo.50-281page2of3Ifyouhaveany questionsorrequire additionalinformation,pleasecontact Mr.ThomasShaubat(804)273-2763.

Sincerely,GeraldT.Bischof Vice President-Nuc COMMONWEALTH OF VIRGINIA))COUNTY OF HENRICO)Theforegoing documentwasacknowledgedbeforeme,inandfortheCountyand Commonwealth aforesaid,todaybyGeraldT.Bischof,whoisVicePresident-NuclearEngineering,ofVirginiaElectricandPowerCompany.Hehasaffirmedbeforemethatheisdulyauthorizedtoexecuteandfiletheforegoing document inbehalfofthatCompany,andthatthestatementsinthe documentaretruetothebestofhis knowledge and belief.Acknowledgedbeforemethis t1? of,2008.My Commission Expires:

//_/J IL/faa.NotaryPublic Commitmentsmadeinthisletter:None.

Attachment:

1.ResponsetoNRCRequestforAdditionalInformation ContainmentLeakageRateTestProgram VICKI L.HULL IiIOIaIY PubIc COINMftW.-

of....,....CCMNftIIIlon

.,.1118 cc:U.S.NuclearRegulatoryCommissionRegionIISamNunnAtlantaFederalCenter61ForsythStreet,SWSuite23T85Atlanta,Georgia30303NRCSeniorResidentInspectorSurryPowerStationStateHealth Commissioner Virginia DepartmentofHealthJamesMadisonBuilding-7thFloor 109 Governor StreetRoom730Richmond,Virginia23219Mr.S.P.LingamNRCProjectManagerU.S.NuclearRegulatoryCommissionOneWhiteFlintNorth11555RockvillePikeRockville,Maryland20852SerialNo.08-0326 DocketNo.50-281page3of3 SerialNo.08-0326 DocketNo.50-281 ATTACHMENT RESPONSETONRCREQUESTFOR ADDITIONAL INFORMATION CONTAINMENTLEAKAGERATETESTPROGRAM VirginiaElectricand Power Company (Dominion)

Surry PowerStationUnit2 SerialNo.08-0326DocketNo.50-281 AttachmentPage1of5 RESPONSETONRC REQUEST FOR ADDITIONAL INFORMATION THE CONTAINMENT LEAKAGE RATE TEST PROGRAM BackgroundByapplicationdatedDecember17,2007(AgencywideDocumentsAccessand ManagementSystemAccessionNumberML073511682),VirginiaElectricandPowerCompany(Dominion)proposedalicenseamendmenttochangeSurryPowerStation,UnitNO.2(Surry2)TechnicalSpecifications(TS).Theproposedchangewouldpermit aone-time5-yearexceptiontothe10-yearfrequencyoftheperformancebasedleakageratetestingprogramforTypeAtests,asrequiredbyRegulatoryGuide(RG)1.163.TocompleteourreviewoftheproposedTSchanges,theNuclearRegulatoryCommissionstaffrequeststhatDominionrespondtothefollowing:

NRC Question 1IdentifytheProbabilisticRiskAnalysis(PRA)versionusedtosupporttheintegratedleakratetestingextensionrequest.Discussthereasonsforthesignificantchangeinthecoredamagefrequency(CDF)andtheintactcontainmentfrequencyrelativetothePRAversionusedtosupportlicenserenewal(i.e.,areductioninCDFfrom3.8E-5to 2.93E-5/yearandareductioninintactcontainmentfrequencyfrom2.2E-5to 3.17E-6/year.)

Dominion ResponseThePRAmodelusedforthelicenserenewalforSurrywasissuedinJune1997andtheassociatedCDFwas3.8E-05/yr.ThereductionintheCDFfrom 3.8E-05/yrto05/yrisduetotwomodelrevisionssincetheissueofthe1997model.Therewere several improvements/revisionsbetweenthereleaseofthe1997modelandthe2000modelresultinginthereductionoftheCDF.Thesechangesincludethefollowingitems.ImprovedmodelingofinitiatingeventfrequenciesPeriodicdataupdate-Additionalcreditsofdis-allowedmaintenanceThereductionintheintactcontainmentfrequencyfrom2.2E-05/yrto 3.17E-06/yrwasaresultoftheLevel2modelrevisionduring2003.TheLevel2modelusedforthe2007ILRTsubmittalwasrevisedin2003toupdatethemodeltocurrentstandards.Thechangesincludearevisionoftheplantdamagestate(PDS)rules,assigningnewPDSnumberstotheLevel1eventtreesandaddinganadditionalbranchforthenon-LERFSGTRevent.Thechangesmadetothemodelresultedinasubstantialdropintheintactcontainmentfrequency.

SerialNo.08-0326 DocketNo.50-281 AttachmentPage2of5 NRC Question 2TableA-2ofAttachment2toyourletterdatedDecember17,2007,providestheestimatedpopulationdoseforeachElectricPowerResearchInstitute(EPRI)accidentclassbasedonthefrequency-weighedsumofthedosesprovidedinTableA-IofyourletterdatedDecember17,2007.However,thepopulationdosesreportedinTableA-2forEPRIClasses2,7,and8areinconsistentwiththefrequency-weightedsumofthedosesfromTableA-I.AlthoughthecorrectdosevalueswereusedforClasses7and8inthemainreport(e.g.,Table2ofyourletterdatedDecember17,2007),theincorrectdosevaluewasusedforClass2.PleasereconcilethepopulationdosevaluesprovidedinTablesA-I,A-2,and2,andupdatetheriskassessmentasappropriate.

Dominion ResponseTheobservationiscorrect.Thus,theClass2dosehasbeenfrequency-weightedandthereviseddosevalueshavebeenpropagatedthroughthebaseline,10year,and15yearmetrics.WiththeClass2doserevisions,thetotalbaseline,10year,and15yeardoseratesremainunchanged.ThesummaryresultsreflectingthereviseddosevaluesforClass2areprovidedintheattachedtable.ThetotalincreaseinLERFresultingfromachangeintheTypeAtestintervalisnotimpactedbythischange.

NRC Question 3Thetotallargeearlyreleasefrequency(LERF)forSurryPowerStation,includingtherequestedchange,isstatedtobe9.79E-7peryear(page18ofAttachment2ofyourletterdatedDecember17,2007).However,thisvaluedoesnotincludethecontributiontoLERFfromexternalevents.AsstatedinSection2.2.4of RG1.174, therisk-acceptanceguidelines(inthiscase,forLERF)areintendedforcomparisonwithafull-scopeassessmentriskassessment,includinginternalandexternalevents.Consistentwiththisguidance,andtotheextentsupportablebytheavailableriskmodelsforSurryPowerStation,provideanestimateofthetotalLERFwhenexternaleventsandtheimpactoftherequestedchangeareincludedwithintheassessment.

Dominion ResponseSurryPowerStationhasexternaleventsmodelsforfireandseismic.ThebaselineCDFforfireandseismicare1.8E-05/yrand1.0E-05/yr,respectively.TheexternaleventsLERFvaluesinvolvingtheTypeAtestinterval(consistentwiththemethodologyusedfortherequestedchange)arecalculatedanddisplayedinthetablebelow.

SerialNo.08-0326DocketNo.50-281 AttachmentPage3of5 Class 3BBase=CDF*ProbClass-3B Class 3B10=Class 3BBase*(10 year multiplier)

Class 3B15=Class 3BBase*(15 year multiplier)

Where: ProbClass-38=0.0027=probabilityoflargepre-existing containment liner leakage.10yearmultiplier=3.33=theaveragetimethataleak detectableonlybyaTypeAtestwouldgoundetectedfrom18months(3yrs/2)to60months(10yrs/2).[60/18=3.33]15year multiplier=5.00=theaveragetimethataleak detectableonlybyaTypeAtestwouldgoundetectedfrom18months(3yrs/2)to90months(15yrs/2).[90/18=5.00]InternalEvents Class 388ase=2.93E-05*0.0027=7.91E-08/yr Class 3810=7.91E-08*3.33=2.63E-07/yr Class 3815=7.91E-08*5.00=3.96E-07/yr Class 388ase=1.8E-05*0.0027=4.86E-08/yr Class 3810=4.86E-08*3.33=1.62E-07/yr Class 3815=4.86E-08*5.00=2.43E-07/yr Seismic Class 388ase=1.0E-05*0.0027=2.70E-08/yr Class 3810=2.70E-08*3.33=8.99E-08/yr Class 3815=2.70E-08*5.00=1.35E-07/yr SerialNo.08-0326 DocketNo.50-281 AttachmentPage4of5InternalEventLERFFireLERFSeismicLERFTotalLERF Class7.91E-08/yr 4.86E-08/yr 2.70E-08/yr 1.55E-07/yr 388ase Class 2.63E-07/yr 1.62E-07/yr 8.99E-08/yr 5.15E-07/yr 3810 Class 3.96E-07/yr 2.43E-07/yr 1.35E-07/yr 7.74E-07/yr 3815Thetotal ALERFfromthebaselinetoonce-per-10years(10yearmetrics)iscalculatedasfollows:

ALERFtotal=Class 3810-Class 388ase=5.15E-07-1.55E-07

=3.60E-07/yr The currentinternaleventsLERF,includingflooding,forSurryPowerStationhasbeencalculatedtobe6.6E-07/yr.Theinternaleventsplusfireand seismiceventsyieldatotalLERFof 6.6E-07+1.2E-07+1.0E-07

=8.82E-07/yr.This ALERF total increases the baselineLERFto8.82E-07+3.60E-07

=1.24E-06/yr.

The ALERFtotalfromthebaselineto once-per-15years(15yearmetrics)is calculatedasfollows:

ALERFtotal=Class 3815-Class 388ase=7.74E-07-1.55E-07

=6.19E-07/yr This ALERF total increasesthebaselineLERFto8.82E-07

+6.19E-07=1.50E-06/yr.

The guidance in RegulatoryGuide1.174statesthatwhenthecalculated increase inLERFisintherangeof1E-07perreactoryearto1E-06perreactoryear, applicationswillbe consideredifthetotalLERFislessthan1E-05perreactoryear.ThetotalLERFvalueforthe15 yearchangeforSPShasbeencalculatedtobe 1.50E-06/yr.Atthis level, RegulatoryGuide1.174definesaLERFincreaseoflessthan1E-06asa"smallchange."Theriskimpactduetotheproposed 15-yearILRTmeetsthiscriterion.The summaryofresultsreflectingtherevisedLERFcalculations,andall other mattersregardingtheNRCRAIdatedMay28,2008isprovidedinthe following table.

SerialNo.08-0326DocketNo.50-281 AttachmentPage5of5 SummaryofResults TableBaseDoseBase Dose 15yr Dose EPRIBaseFreqBase (3/10)Person-Rate 10yr Freq 10yr DoseRate10yr15yrFreq Rate 15yr Class IRx-yrFreq 1 Rx-yr Rem Person-Rem/yr 1 Rx-yr Person-Rem/yr Metrics I Rx-yr Person-Metrics Rem/yr 1 3.17E-06 2.30E-06 5.98E+02 1.38E-03 2.77E-07 1.66E-04 O.OOE-OO O.OOE+OO 2 6.52E-10 6.52E-10 4.71E+05 3.07E-04 6.52E-10 3.07E-04 6.52E-10 3.07E-04 3AN/A7.91E-07 5.98E+03 4.73E-03 2.63E-06 1.57E-02 3.96E-06 2.37E-02 3BN/A7.91E-08 2.09E+04 1.65E-03 2.63E-07 5.50E-03 3.96E-07 8.28E-03 4 N/A N/A N/A N/A N/A N/A N/A N/A 5 N/A N/A N/A N/A N/A N/A N/A N/A 6 N/A N/A N/A N/A N/A N/A N/A N/A 7 2.36E-05 2.36E-05 1.00E+05 2.36 2.36E-05 2.36 2.36E-05 2.36E+00 8 2.49E-06 2.49E-063.61E+06 8.99 2.49E-06 8.99 2.49E-06 8.99E+00 TOTAL 2.93E-05 2.93E-05 N/A 11.36 2.93E-05 11.37 3.04E-05 11.38 (CDF)(CDF)(CDF)(CDF) Change 1.36E-02 2.42E-02 from BaseILRTDR%of total 0.056%0.186%0.281%doseChangeinILRTDR 0.130%.0225%from Base LERF 8.82E-07 1.24E-06 1.50E-06 3.60E-07 6.19E-07 From baseCCFP,%89.5%90.1%87.0%%0.60%-3.0%CDF 2.93E-05