ML090150378

Supplemental Response to the NRC Generic Letter 2008-01, Managing Gas Accumulation in Emergency Core Cooling, Decay Heat Removal, and Containment Spray Systems

ML090150378
Person / Time
Site:	Millstone
Issue date:	01/15/2009
From:	Matthews W R Dominion, Dominion Nuclear Connecticut
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
09-010, GL-08-001
Download: ML090150378 (3)

Text

Dominion Nuclear Connecticut, Inc.';000 Dominion Boulevard, Glen Allen, Virginia 2.\060 Web Address: www.dom.corn January15,2009 U.S.Nuclear Regulatory Commission Attention:

DocumentControlDesk One WhiteFlintNorth11555RockvilleRockville,MD 20852-2738SerialNo.NLOS/GAWDocketNo.LicenseNo.09-010 RO 50-423 NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.MILLSTONE POWERSTATIONUNIT3 SUPPLEMENTAL RESPONSETOTHENRC GENERIC LETTER 2008-01, MANAGING GAS ACCUMULATION IN EMERGENCY CORE COOLING,DECAYHEAT REMOVAL, AND CONTAINMENT SPRAY SYSTEMSThisletter supplementsthenine-monthresponseto GenericLetter(GL)2008-01for MillstonePowerStationUnit3(MPS3)thatwasprovidedinDominion Nuclear Connecticut, Inc.(DNC)letterdated October14,2008(ADAMS Accession ML082890266).Specitically,thisletter completes an alternativecourseofactionforrespondingtotheGl.thatwasapprovedinNuclearRegulatory Commission (NRC)letterdatedJuly23,:2008 (ADAMS Accession ML081980640),whichallowedDNCto acquire confirmatorysysteminformationduringtheMPS3fall2008refuelingoutage (3R12).TheDNC nine-monthresponsetotheGLcontaineda descriptionofa technical evaluationofthe EmergencyCoreCoolingSystem(ECCS),ResidualHeatRemovalsystem(RHS),and ContainmentSpray(CS)system,whichwas performedtoassure DNC's capabilitytomaintaingasvoidinglessthanthe amount that challenges operabilityofthesesystems.Thenine-monthreport summarized the corrective actionstobe completedforthegas accumulation managementplans,assuring compliance withdesign,licensingbasesandquality assurancecriteriainSectionsIII,V,XI,XVI,and XVII of AppendixBto10CFRPart50.During3R12which ended on November 24,2008,DNCcompletedtherequiredGL2008-01system walkdownsatMPS3.Subsequently,plannedgas accumulation management improvementswererefinedandthetechnical evaluationwasupdated accordingly.Theballanceofthisletterprovidesadditionalinformationrelativetothe nine-monthresponseforMPS3.Thecorrectiveactionsandthe associated schedule previously discussedinthe nine-monthresponsetotheGLarenotchanged.DNC confirmsthegas accumulation management plans currentlyinplaceatMPS3, augmentedbyplannedcorrectiveactionsdescribedinthe nine-monthletter,arein compliancewithappllicable quality assurancecriteria,designandlicensingbases.

SerialNo.09-010 DocketNo.50-423Page2of3 Walkdowns previously describedinthe nine-monthresponseand scheduledfor3R12arecomplete, exceptforHighPressureSafetyInjection(HPSI)inside containmentpipingfrom penetration(51)tothereactor coolantsystem(RCS)coldlegs.

Furtherreviewof theseHPSIlines determinedflowratesduring surveillance testing were adequatetofullysweepthepiping.Returning systemstoserviceduring3R12 included numerous confirmatory ultrasonictesting(UT) inspectionstoverifypipingwas adequatelyfilled.The correctiveactionprocessisbeingusedto identify improvementstothe system restorationprocesstoensurethe systemsarefull.A corrective actionplanisinplaceas describedbythe nine-monthresponsetotheGL,whichwill improvethefillandvent processes and proceduresandaddress lessonslearnedfrom system restoration deficiencies encounteredduring3R12.Thisplanwillusethe insights gainedfromGL2008-01 evaluations including walkdowns, slope measurement,andUT information obtainedduring3R12.The walkdowns, identificationoflocalvoid locationsfromplannedUT inspections,andplannedsystem enhancementsresultedinthe following modifications implementedduring3R12aswellas Licensee Event Report 2008-004-00,GasVoid Discoveredinthe EmergencyCoreCoolingSystem SuctionLine,dated December19,2008:*New vent valve 3SIL*V817wasinstalledinthe24-inchsuctionline entering the AuxiliaryBuildingfromtherefueling waterstoragetank.*Newventvalve 3SIL*V816wasinstalledinan8-inchline, upstream of Penetration95and3SIL*MV8840intheRHSpumps dischargetohotlegsloops2and4.*Newventvalve3SIH*V791wasinstalledoutsideof containment at Penetration98intheHPSI discharge piping.*Vent valve 3SIH*V993inHPSIcommonsuctionpipingwasrelocatedtothehighpoint.

Please contact Mr.Geoffrey A.Wertzat(804)273-3572ifyouhaveany questions or require additional information.

SerialNo.09-010 Docket No.50-423Page3of3 Sincerely, e..v£t.-I QJ t..ea.William R.Matthews Senior Vice President-Nuclear Operations COMMONWEALTH OF VIRGINIA-VICKIL.HULLNotary Public Commonwealth of Virginia 140542My Commission Expires May31.2010Notary Publiccc:U.S.NuclearRegulatoryCommissionRegionI Regional Administrator 475 Allendale RoadKingofPrussia,PA 19406-1415 Commitmentsmadeinthisletter:None Attachments:

None My Commission Expires: COUNTY OF HENRICO The foregoing document was acknowledgedbeforeme,inandforthe County and Commonwealth aforesaid, today by William R.Matthews,whois Senior Vice President-Nuclear Operations of Dominion Nuclear Connecticut,Inc.Hehas affirmedbeforemethatheisduly authorized to executeandfilethe foregoing document in behalfofthat company,andthatthe statementsinthe documentaretruetothebestofhis knowledgeandbelief.

• W Acknowledged beforemethis/5;;dayof ,2009.NRC SeniorResidentInspector MillstonePowerStationMs.C.J.Sanders NRC Project ManagerU.S.Nuclear Regulatory Commission One WhiteFlintNorthMailStop 08-8311555RockvillePikeRockville,MD 20852-2738