GNRO-2015/00038, Response to Request for Additional Information Regarding Fluence License Amendment Request, Request for Commitment

Response to Request for Additional Information Regarding Fluence License Amendment Request, Request for Commitment

ML15162B088
Person / Time
Site:	Grand Gulf
Issue date:	06/11/2015
From:	Kevin Mulligan Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GNRO-2015/00038
Download: ML15162B088 (7)

Text

GNRO-2015/00038June11,2015 u.s.NuclearRegulatory CommissionAttn:DocumentControlDeskWashington,DC20555-0001 Entergy Operations, Inc.P.o.Box 756PortGibson,MS 39150 Kevin MulliganSiteVice PresidentGrandGulfNuclearStation Tel.(601)437-7500

REFERENCES:

ResponsetoRequestfor AdditionalInformationRegardingFluenceLicense AmendmentRequest,Requestfor Commitment Grand Gulf NuclearStation,Unit1DocketNo.50-416LicenseNo.NPF-291.U.S.Nuclear Regulatory Commission Letter,"RequestsforAdditionalInformationfortheReviewoftheGrandGulf Nuclear Station,LicenseRenewal Application," dated August 28,2013 (AccessionNo.ML13227A394)2.Grand Gulf NuclearStationLetter,"ResponsetoRequestsfor Additional Information(RAI)set47,"dated September 23,2013 in letter GNRO-2013/00069(AccessionNo.ML13266A368)3.U.S.Nuclear Regulatory CommissionRegulatoryGuide,RegulatoryGuide1.190,datedMarch2001(AccessionNo.ML010890301)4.GrandGulf NuclearStationLetter GNRO-2014/00080,"ApplicationtoReviseGrandGulfNuclearStationUnit1'sCurrentFluence Methodologyfrom0EFPYThroughtheEndofExtendedOperationstoaSingleFluenceMethod,"dated November 21,2014.5.ResponsetoRequestfor SupplementalInformationdatedFebruary 18,2015inletter GNRO-2015/00011 (ADAMS Accession No.ML15049A536).6.Requestfor Additional InformationRegardingFluenceLicense AmendmentRequestdatedApril3,2015 (GNRI-2015/00041).7.GrandGulf NuclearStationLetter GNRO-2015/00031,"ResponsetoRequestfor AdditionalInformationRegardingFluenceLicense AmendmentRequest"datedMay8,2015.

Sincerely, GNRO-2015/00038Page2of3

DearSirorMadam:

In accordancewiththe provisions of Section50.90ofTitle10CodeofFederal Regulations(10CFR),Entergy Operations, Inc.(Entergy)is submitting responsetoa Request for AdditionalInformation(RAI) regarding an amendment requesttorevisetheexistinglicensebasisforGrandGulf NuclearStation(GGNS),Unit1.Inletter GNRO-2015/00031datedMay8,2015, Entergystatedtheywere currently indiscussionswithGEH regarding feasibilityoftaking scrapings and/or installing dosimetrycapsulesandwouldprovidea responsetoRAI question4ina separate letterwithin60daysfromthedateoftheMay8letter.

RAI question4isforthe proposed amendmenttoreviseGrand Gulf NuclearStation,Unit1'slicensebasistoadoptasingle fluence calculation methodology.

ResponsetotheRAIisneededtoaddressthe Staff'srequestthatGGNSmakea Regulatory Commitmenttoinstall dosimetry capsules and/or scrapingsinorderto qualifythe3D fluencemethodfor fluence calculationsoutsideofthebeltlineregionandasecond Regulatory Commitmenttoconfirmthatfuture calculated-to-measured (e/M)fluencevaluesatthe dosimetry location(s) are reasonably closetoone including explicit definition of"reasonablyclosetoone"(e.g.C/M greaterthan0.8)andplanstoaddressany substantial disagreements.

Attachment1provides responses to Request for Additional Information (RAI)question 4.Thislettercontainsnew commitmentswhichare identified in Attachment2.Ifyouhaveany questionsorrequire additional information, please contact Mr.JamesNadeauat(601) 2103.Ideclare underpenaltyofperjurythatthe foregoingistrueandcorrect.

Executed onJune11,2015.

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S KJM/ras GNRO-2015/00038Page3of3cc:with Attachments u.s.Nuclear Regulatory CommissionATTN:Ms.RebeccaRichardson, Project ManagerProjectsBranch1DivisionofLicenseRenewalOfficeof Nuclear Reactor Regulation U.S.Nuclear Regulatory CommissionMailStop 0-11 F1 Washington,DC20555cc:without Attachments u.S.Nuclear Regulatory CommissionATTN:Mr.MarkDapas,(w/2)

Regional Administrator,RegionIV1600East Lamar BoulevardArlington,TX76011-4511 NRC Senior Resident Inspector Grand Gulf Nuclear StationPortGibson,MS39150U.S.Nuclear Regulatory CommissionATTN:Mr.AlanWang, NRR/DORL (w/2)MailStopOWFN8B1 Washington,DC20555-0001Dr.MaryCurrier,M.D.,M.P.HStateHealth Officer Mississippi DepartmentofHealthP.O.Box1700Jackson,MS 39215-1700 Attachment 1 Grand Gulf Nuclear Station GNRO-2015/00038 Response to Request for Additional Information RAI4 Attachment1of GNRO-2015/00038 Page1of1RAI4fromApril3, 2015 (reference 6): In GNRO-2015/00011

, Attachment1,itis stated that"this letter containsnonew commitments." However, the responsetoRAI1ainthe same document states: Installing dosimetry capsules and/or taking scrapings in specified areas outsideofthe beltline region would provide dosimetry datafora future benchmark analysis outsideofthe beltline region.The uncertaintyinthe fluence calculations at locations abovethetopofthe core is dominated by uncertaintyinthe water density.Taking scrapings and/or inserting dosimetry in these locations (during future refueling outages)would not only provide benchmarking data,butit would also provide the data needed to check the output from thermal hydraulics codes thatcanbeusedin future improvementsofthe upper region water density modeling.The NRC staff request that Entergy provide a regulatory commitment to install dosimetry capsules and/or scrapings, to qualifythe3D fluence method for fluence calculations outsideofthe beltline region.Provide details regarding the plans and schedule for installing dosimetry capsules and/or scrapings including the proposed locations for dosimetry capsule installation.

Also, provide a regulatory commitment to confirm that future calculated-to-measured (C/M)fluence valuesatthe dosimetry location(s) are reasonably closetoone including explicit definition of"reasonably closetoone"(e.g.C/M greaterthan0.8)and plans to address any substantial disagreements.RAI4 Response: Activities are being scheduled to sample the GGNS shroud,topguide,and possibly other internal componentssuchasfuel bundle bail handles in order to obtain a better water density distribution forthe3D TORT modelandto benchmarkitwith dosimetry materials takenfromthe shroudandtop guide.These activities will provide dosimetry data to qualifytheMPM3D Fluence Calculation Method for fluence calculations outside the beltlineregion.MPMhas provided a proposal to identify the locations and material volumeforthe recommended approximately 15 samplesandwill detail the exact cut locations and provide details concerninghowthe samplesaretobe takenfromthe GGNS structures.

Entergy reservestherightto re-evaluate the area above the activefuelin more detail at a later date.Ithasbeen verified that thereisnoneedto sample the vessel since removaloftheclad would lead to corrosion problems,anditisnot needed sinceitis known that thereissolid water between the shroud and vesselandthiscanbe accurately modeled in TORT.Since the objectiveofthe workisto benchmark an advanced modelofthe water density distributioninthe steam dome region, samples are needed at locations where spatial variationisnota significant factorandat various transport distances through the steam.If technical evaluation of collecting samples (Le.drilling holes)from the shroud and/or top guide prohibits sample collection or determines additional actions are required which cannot be performed priortothe 2016 refueling outage, plans will continue to perform those additional actions in order to prepare for sample collection during the 2018 refueling outage.Itis expected that not onlywillthe revised TORT model be substantially improved,butitis also anticipated thatitwillgive calculated-to-measured(C/M)ratios within20%,ashasbeen achieved in the beltline region.Entergy commits to identify the sample locationsandto schedule collection of samples from outside the beltline region.Entergy's objectiveistohavetheC/Mratio within 20%for the structures located abovethecore.This should be achievablewiththe improved water density data thatwillbe obtainedforthe steam dome region.Therefore, Entergy commitstothe objective,withthe expectation that a+/-20%C/M should be achievable with additional analysis.

Attachment 2 Grand Gulf Nuclear Station GNRO-2015/00038 List of Regulatory Commitments Attachment2to GNRO-2015/00038Page1of1LISTOF REGULATORY COMMITMENTSThistable identifies actions discussedinthis letterforwhich Entergy commitstoperform.Anyotheractions discussedinthis submittal are describedfortheNRC's informationandare not commitments.

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Entergy willidentifytheoutsideof./October30,2015thebeltlineregion dosimetry sample locations Entergy will schedule collection of./December 30, 2015samplesfromoutsidethebeltline regionEntergywillconfirmthat future C/M./November 30, 2016 fluencevaluesat the dosimetry sample locations are reasonablyclosetooneEntergywillincludethe definition of./November 30, 2016"reasonablyclosetoone" regarding C/Mfluencevalues at the dosimetry sample locationsEntergywillprovideplans to./December30,2016addressiffuture C/M fluencevaluesat the dosimetry samplelocationsare not reasonably close to one