ML17264B072

Forwards Response to Questions from NRC Staff on Proposed Mod of Spent Fuel Storage Pool,Dtd 970331

ML17264B072
Person / Time
Site:	Ginna
Issue date:	10/10/1997
From:	MECREDY R C ROCHESTER GAS & ELECTRIC CORP.
To:	VISSING G S NRC (Affiliation Not Assigned), NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
TAC-M95759, NUDOCS 9710210233
Download: ML17264B072 (22)

Text

.CATEGORY1REGULATOINFORMATIONDISTRIBUTION'TEM(RIDS)ACCESSIONA'NBR:9710210233DOC.DATE:97/10/10NOTARIZED:NOFACIL:50-244RobertEmmetGinnaNuclearPlant,Unit1,RochesterGAUTH.NAME.;AUTHORAFFILIATIONMECREDY,R.C.RochesterGas6ElectricCorp.RECIP.NAMERECIPIENTAFFILIATIONVISSINGIG.S.DOCKETI05000244I

SUBJECT:

ForwardsresponsetoquestionsfromNRCstaffonproposedmodofspentfuelstoragepool,dtd970331.DISTRIBUTIONCODE:AOOIDCOPIESRECEIVED:LTRJENCLJSIZE:I+TITLE:ORSubmittal:GeneralDistributionNOTES:LicenseExpdateinaccordancewith10CFR2,2.109(9/19/72).05000244ERECIPIENTIDCODE/NAMEPD1-1LAVISSINGEG.INTERN:FILECENTE/EMCBNRR/DSSA/SPLBNUDOCS-ABSTRACTEXTERNAL:NOACCOPIESLTTRENCL11111111111111RECIPIENTIDCODE/NAMEPD1-1PDNRR/DE/ECGB/ANRR/DRCH/HICBNRR/DSSA/SRXBOGC/HDS3NRCPDRCOPIESLTTRENCL1111111110110RDNNOTETOALLNRIDS"RECIPIENTS:PLEASEHELPUSTOREDUCEWASTE.TOHAVEYOURNAMEORORGANIZATIONREMOVEDFROMDISTRIBUTIONLISTSORREDUCETHENUMBEROFCOPIESRECEIVEDBYYOUORYOURORGANIZATION,CONTACTTHEDOCUMENTCONTROLDESK(DCD)ONEXTENSION415-2083TOTALNUMBEROFCOPIESREQUIRED:LTTR13ENCL12 ANDROCHESTERGA9ANDEIECTRICCORPORATION~89EASTAVENUE,ROCHESTER,N.Y14649-0001AREACODE716546-2700ROBERTC.MECREDYVicepresidentNuclearOperationsOctober10,1997U.S.NuclearRegulatoryCommissionDocumentControlDeskAttn:GuyS.VissingProjectDirectorateI-1Washington,D.C.20555

Subject:

ResponsetoQuestionsfromNRCStaffonProposedModificationoftheGinnaSpentFuelStoragePool(TACNo.M95759)R.E.GinnaNuclearPowerPlantDocketNo.50-244Ref.(1):LetterfromG.S.Vissing(NRC)toR.C.Mecredy(RGGE),

Subject:

RequestforAdditionalInformation-SpentFuelPoolModifications(TACNo.M95759),datedAugust25,1997.

DearMr.Vissing:

ByReference1,theNRCstaffrequestedadditionalinformationregardingtheproposedModificationoftheGinnaSpentFuelStoragePooldatedMarch31,1997.EnclosedareresponsestoeachofthequestionssubmittedbytheNRCstaff.Veryrulyyours,RobertC.MecreJPO~'",fan97f02'f023397fOi0PDRADOCK05000244PPDRlllllllllllllllllllllllllllllllltlllllll Mr.GuyS.Vissing(MailStop14B2)SeniorProjectManagerProjectDirectorateI-1Washington,D.C.20555U.S.NuclearRegulatoryCommissionRegionI475AllendaleRoadKingofPrussia,PA19406GinnaSeniorResidentInspectorMr.PaulD.EddyStateofNewYorkDepartmentofPublicService3EmpireStatePlaza',TenthFloorAlbany,NY12223-1350 U.S.NRCG.S.VissingA-1October10,1997uestionNo.1:InthesubmittalyouhaveindicatedthatsomespentfuelrackswithBoraflex,usedpresentlyinthespentfitelpool(SFP),willberetained.AlthoughtheanalysisdescribedinthesubmittalwasbasedonaveryconservativeestimationofthedegreeofBoraflexdegradationduringitsexposureintheSFP,experiencehasshownthatthisdegradationdependsonseveralfactorswhichmaybedificulttoestimate.Forexample,maintaininglowsilicalevelintheSFPwatermayacceleratedegradationofthepolymerwithconsequentialhigherlossonboroncarbide.Therefore,many,plantsinstitutedsurveillanceprogramsconsistingofinspectionofcouponsandlormeasurementofsilicaconcentrationintheSFPwater.AreyouintendingtohaveaBoraflexsurveillanceprograminthererackedSFP?Ifso,describetheprogram.Ifnot,provideyourbasis.R~esense:RG&Ehascommittedtomonitorthereactivesilicalevelsinthespentfuelpoolonamonthlybasistodetectandevaluateunusualtrendsofabnormallevels(Reference1).RG&Eiscurrentlymonitoringsilicalevelsandwillcontinuethissurveillanceafterrerackingofthespentfuelpool.BecausethespentfuelrackswithBoraflexdonothavecouponswhichwouldallowperiodicinspection,RG&EhasoutlinedinReference1severalactionstomonitorthepotentialforBoraflexdegradation.Someoftheseactivities,asdescribedinReference1,willcontinueafter.theproposedrerackingofthespentfuelpool.Ifthereareanyquestionsregardingthisactionplan,pleaseprovidearequestforadditionalinformation.

Reference:

11.I.etterfromR.C.Mecredy(RG&E)toG.S.Vissing(NRC),datedOctober24,1996;

SUBJECT:

RESPONSETONRCGENERICLETI'ER96-04,DATEDJUNE26,1996,ONBORAFLEXDEGRADATIONINSPENTFUELRACKS.

U.S.NRCG.S.Vis'singA-2October10,1997uestion.No.2:1nthenewfuelracks,boratedstainlesssteelpanelswillremainincontactwiththecomponentsmadefromaregularstainlesssteel.Becauseoftheslightlydiferentchemicalcompositionofthesematerials,galvaniccellsmayforminaboricacidsolutionandthismaybeasourceofcorrosion.Showthatthisphenomenonwillnotcontributetoasignificantdegradationofthepoisonmaterial.R~esoose:Theoretically,theuseofBoratedStainlessSteel(BSS)panelsastheabsorbermaterialinSpentFuelStorageRacksisassessedasamuchmorebenignconditionthantheuseofporousaluminum-boroncarbidepanels.Thelatter,whichareknowntohaveafargreaterpotentialforchemicalreactionwiththepoolwaterundernormalpoolconditions,havebeenusedinSpentFuelStorageapplicationsinthepast.InordertoverifythehypothesisthatBSSwillbeessentiallyinertunderpoolconditions,aseriesofcorrosiontestshavebeenperformedunderveryadverseconditionsasdiscussedbelow.CorrosiontestsofBSScouponsofvariousconfigurationsandboroncontentswereconductedseveralyearsagobyCarpenterTechnologyCorp.,Reading,PAundercontracttoEPRI.TheresultsofthesetestshavebeenpublishedinEPRIReportTR-100784,June1992'.Thetestconditionswere2000PPMboricacidat154'Fforanexposuretimeofsixmonths.The154'Ftesttemperaturewasbasedonthemaximumallowablebulkpoolwatertemperatureforspentfuelstoragepools.Specimenconfigurationsincludedsimpleimmersion,creviced,air-purgedandgalvanically-coupledspecimens.Thegalvanically-coupledspecimensconsistedofBSScoupledwithType304.Noneofthetwenty-six(26)simpleimmersion,crevicedorair-purgedspecimensexhibitedanymeasurableweightchangewiththeexceptionofonespecimenwhichhadbeenwelded.Twoofthethreegalvanically-coupledspecimensexhibitedaverysmallweightloss,andthethirdnomeasurableweightchange.Minorrustingwasnotedonthegalvanically-coupledspecimens.TheresultsofthesetestsindicatedthatBSSexhibitsexcellentcorrosionresistancetospentfuelpoolwateratmaximumpooloperatingtemperatures.Inadditiontotheabovetestsat154'F,elevatedtemperaturecorrosiontestsofBSShaverecentlybeenconductedin2450PPMboricacidsolutionat239'Fusingarecirculatingautoclave'.TheselectionofthetesttemperaturewasbasedonthehighestlocalpoolwatertemperaturewhichcouldoccurinanycellintheGinnaSFP(saturationtemperaturebasedonminimumheightof23feetofwateroveranycell).TheBSSmaterialusedforthesetestswasASTMA887-89,GradeB,TypeB7with1.9%boron,whichisslightlyhigherthanthemaximumboroncontentof1.82%intheBSSmaterialintendedforuseintheGinnaSFP,andthereforeisconservativelyrepresentativeoftheGinnamaterial.Testspecimensincluded lU.S.NRCG.S.VidsingA-3October10,1997simpleimmersion(freecorrosion),galvanically-coupledandartificially-creviced(ASTMG78-89)configurations.Thegalvanically-coupledspecimensincludedBSScoupledwithType304LandwithZircaloy4.Specimenswereexposedfortotaltimesof30and60days(720and1440hours).Theresultsofthesetestsshowedthatallspecimensexhibitedstable,passivebehaviorintheboricacidenvironmentwithverylowcorrosionrates.TheaveragecorrosionrateforthesimpleimmersionandcrevicedBSSspecimenswas.0167MilsPerYear(MPY)and.0320MPY,respectively.TheaveragecorrosionrateforthegalvanicallycoupledBSSspecimenswas.033MPY.Thesecorrosionratesindicatethatintheworstcasecondition(i.e.BSSgalvanicallycoupledto304LandZircaloy4atasustainedwatertemperatureof239'F),thethicknesslossovera40yearexposurewouldbeontheorderof1.3mils(.0013"),orapproximately1%ofthetotalthicknessofaBSSsheet.TheminimumrequiredthicknessoftheBSSsheetmaterialfortheGinnaSFPrackswas2.5mm(.098")or3.0mm(.118"),dependingonracktype.Theactualthicknessofthefinishedsheets,however,exceededtheminimumthicknessbyaconsiderablemargin.Forthe2.5mmsheets,theactualthicknessvaluesmeasuredduringfinaldimensionalchecksonthesheets(eachsheetwasmeasured)wereintherange2.65mm-2.90mm(.104"-.114")andforthe3.0mmsheets,3.15mm-3.50mm(.124"-.138").Itcaribeseenthatalossofthicknessduetocorrosionontheorderof.001"-.002"ismuchlessthantheextramargininthicknessintheplatesandthereforedoesnotresultinaviolationoftheassumptionsinthelicensingreport.Thelossofneutronabsorberthicknessduetogalvaniccorrosionisthereforenegligibleandcannotleadtodegradationoftheabsorbermaterialbelowminimumdesigncriteria.ItshouldbenotedthatexposureoftheBSSmaterialatsuchahightemperature(239'F)forprolongedperiodsoftimeisanextremeconditionwhichdoesnotrepresentnormalpooloperatingconditions.Theexittemperaturesforlocalfuelbundlecooling,basedonboundingconditions,arewellbelowthetemperatureof239'F.'saresult,thecorrosionratesexpectedfromexposureoftheBSSpanelstonormalpooloperatingconditionswouldbesignificantlylowerthanthoseattheelevatedtemperatures.Thecorrosionratesmeasuredintheelevatedtemperaturetests,therefore,representaboundingcondition.~Reference1.Smith,R.J.,Loomis,G.W.,Deltete,C.P.,BoratedtainlessSteelAlicationinSen-FieltoraeRacks,EPRITR-100784,Project2813-21,FinalReport,June1992,p.3-25.2.ATEATechnicalSpecification2226.031.000,BoratedStainlessSteelAlicatinin~FuelRack.

I'll+IIa,.5 U.S.NRCG.S.VidsingOctober10,19973.LetterfromR.C.Mecredy(RG&E)toG.S.Vissing(NRC),datedMarch31,1997;

SUBJECT:

APPLICATIONFORAMENDMENTTOFACILITYOPERATINGLICENSE,REVISEDSPENTFUELPOOLSTORAGEREQUIREMENTS.ATTACHMENT:R.E.GINNANUCLEARPOWERPLANT,SPENTFUELPOOLRERACKING,LICENSINGREPORT,SECTION5.0,THERMAL-HYDRAULICEVALUATION.

U.,S.NRCG.S.VissingA-5October10,1997uestionNo.3:Describetheinspectionprogramofboratedstainlesssteelpanelsbeforetheirincorporationintothespentfuelracks.Re~once:~BackroundTheboratedstainlesssteelfortheGinnaSFPrackswasspecifiedasASTMA887-89,GradeB,TypeB6/B7withaminimumboroncontentof1.70%.Boratedstainlesssteel(BSS)heatswereelectric-furnacemeltedandbottom-pouredintoingotsattheBOHLER/UDDEHOLMmeltfacilityinKapfenberg,Austria.ThesteelchemistryisbasedonType304stainlesssteel.Thecarboncontentisrestrictedto.04%max.,andphosphorus,sulfur,andnitrogenarecontrolledatverylowlevels.Heatanalysesarecheckedbyextractingachillcastsamplefromeachmeltandanalyzingspectrographicallypriortopouringtheingots.TheheatanalysesforthefourheatsofmaterialmeltedfortheGinnaSFPracksarelistedinTable1.Ingotswerehot-reducedtoslabs,andthenfurtherreducedbyhot-rollingtosheetsatBOHLERBlecheinHonigsberg,Austria.Therollingprocessconsistedofreductionsintheprincipal(longitudinal)rollingdirectiontoapproximately10mmthickness,thenfurtherreductionbycross-rollinginthetransversedirection,andfinalrollingintheprincipaldirectiontofinalthickness.Afterhotrolling,finishingoperationswereperformedatBOHLERBleche,Murzzuschlag,Austria.Theseoperationsincludedrollerleveling,solutionannealing,surfacegrinding,lasercuttingtospecifiedsheetdimensions,andpickling.Sheetproductwasdividedintolotsduringthefinishingoperations.Alotwasdefinedasproductfromoneheat,oneheat-treatmentbatch,andonethickness.TheBSSmaterialfortheGinnaSFPconsistedofeleven(11)lots.InsectionsandTestPerfrmedatBOHLERBlecheThefollowinginspectionsoftheBSSsheetswereperformedatBOHLERBlechepriortofinalacceptanceofthematerial:~VisualInspectionBothsidesofeachsheetwerevisuallyinspectedaftergrindingforthepresenceof U.S.NRCG.S.VidsingA-6October10,1997burrs,scratches,orothersurfaceblemisheswhichmightinterferewithorcausedamagetofuelassembliesduringinsertioninto,orremovalfrom,theracks.Suchsurfaceconditionsweredressedbybuffingorlightsanding.~DimensionalInspectionsThelengthandwidthofeachsheetwasmeasured.Thethicknessofeachsheetwasmeasuredatsixdifferentlocationsusingcalibratedmicrometers.~MechanicalPropertiesUltimatetensilestrength,yieldstrength,elongation,andhardnessweremeasuredbydestructivetensiletestingonasamplecutfromonesheetfromeachlot.TheresultsofthesetestsallmeetthemechanicalpropertiesrequirementsofASTMA887-89(seeTable2).Theexcellentductilityvalues(10%-16%,substantiallyabovetheminimumspecificationrequirementof6%)areindicativeofhomogeneousdistributionoffineboridesinthematerial.ItshouldbenotedthatalthoughtheproductfullymeetstheASTMacceptancecriteria,therearenodesignrequirementsformechanicalpropertiesofBSSintheGinnaSFPapplication.ChemicalAnalyses(Productanalysesbywetchemicalanalysis)Productchemicalanalyseswereobtainedfromasamplecutfromonesheetfromeachheat.Inaddition,sampleswerecutfromonesheetfromeachlotandanalyzedforcarbonandboron.BoronanalyseswereperformedbydigestionofthesampleintoaqueoussolutionandanalyzingbyICP(InductivelyCoupledPlasma).TheresultsoftheseanalysesarepresentedinTable3.AllvaluesmeetthechemicalrequirementsofASTMA887-89TypeB6/B7.Allboronvaluesexceedtheminimumrequirementof1.70%;-ItshouldbenotedthattheproductanalysesinTable3areinexcellentagreementwiththeheatanalyses(Table1).ChemicalAnalyses(Boroncontentbywetchemicalanalysis)Fifty(50)locationswithinonesheetfromHeatC70780weresampledandanalyzedforborontoestablishthehomogeneityofborondistributionwithinonesheet.Thesevaluesallfellwithintherange1.78%to1.82%boron(meanvalue1.80%,standarddeviation.0117%boron).ChemicalAnalyses(Boroncontentbywetchemicalanalysis)Onesamplewascutfromeachof51sheetsselectedfromthetotalpopulationof380sheetsandanalyzedforboroncontent.Thenumberofsamplesselectedfromeachof 0~'r U.S.NRCG.S.VissingA-7October10,1997thefourheatsandtherangeofboronvaluesforeachsamplesetisasfollows:TotalSheets~amleSize%BoronHeatB00021HeatB04901HeatC70780HeatC707961382798013samples8samples20samples10samples1.75-1.77%1.75-1.77%1.79-1.81%1.75-1.79%~'EN-3NeutronAttenuationMeasurementsDescritionofJEN-3DeviceandTe.MehdTheJEN-3deviceisasolidstatedetectorwhichcontainsaCf-252source.Thedeviceisshapedlikeateapotwithahandle.Thefronthalfofthedeviceisthedetector,andthebackhalfcontainsthesource.Thehandleisapproximately2feetinlength.Thedoseatthetopofthedeviceis30mrem/hour.Theefficiencyforneutronsisapproximately0.1%.Atablewhichisusedtoreflectneutronsismadeofpolyethylenewhichisapproximately3"thick.Theboratedstainlesssteel(BSS)sheettobeanalyzedisplacedbetweenthedetectorandthetable.Theneutronswhichareemittedbythesourcepassthroughthestainlesssteelandarethenreflectedbackbytheplastictable.Theenergyoftheneutronsisalsoreduced.Thosethermalizedneutronsareattenuatedbytheboratedstainlesssteel.Thefewerthecountsrecordedbythedetector,thegreatertheboronloadingintheBSSsheets.Theboronloadingcalculationsareinfluencedbythefollowingfactors:a)Theactualpercentboron;b)ThethicknessoftheBSSsheetmaterial;andc)Thepowersupplyforthedetector.Initially,thepowersupplyforthedetectorwasasourceofsystematicerror.Afterinvestigatingtheoperatingprinciplesoftheinstrument,thesourceoferrorwaseliminatedanderroneoustestresultsfromtheinitialmeasurementswereeliminatedfromconsideration.TheabilityoftheJEN-3instrumenttofunctionproperlyisinfluencedbyboththethicknessoftheBSSmaterialandtheboronloading.TherelationshipbetweenthecountsrecordedbytheJEN-3detectorandboronloadingisanegativeexponentialrelationship.Allcalibrationcurvesweredevelopedusinglog-logplots.

U.S.NRCG.S.VihsingA-8October10,1997InsectionProramCalibrationCurve-AcalibrationcurveforthestatisticalanalysisofBSSwasdevelopedusingdestructivechemicaltestingandneutronalbedoanalysiswiththeJEN-3.TheresponseoftheJEN-3deviceasafunctionofboronloadinginBSSsheetsofvaryingboroncontentandthicknesswasestablishedusingdestructivechemicalanalysis.Boroncontentrangedfrom1.2%to1.9%,andsheetthicknessfrom2.0mmto3.5mm.BoronanalyseswereperformedbyBOHLERatthecorporatechemistrylaboratoryinKapfenburg,Austria.Thicknesswasmeasuredusingacalibratedultrasonicthicknessmeter(calibrationrecordsforthemeterandtechniciantrainingrecordswerereviewedandfoundtobesatisfactory).TheJEN-3devicewasresponsecheckedonadailybasistoverifyinstrumentoperability.TheserecordsweremaintainedforreviewandapprovalduringallQAsurveillanceactivitiesperformedbyFTI,ATEA,orRG&E.Theresultingcalibrationcurvewasanegativeexponentialline(log-logplot)withacorrelationconfidenceofapproximately99.9%.2)VerificationofBoronContent-TheneutronattenuationcharacteristicsofallBSSsheetswasmeasuredatonerandomlyselectedlocationusingtheJEN-3device.SheetthicknesswasalsomeasuredattheexactlocationwheretheJEN-3measurementwastaken.TheboronloadingineachsheetwascalculatedfromtheJEN-3measurementusingtheequationdevelopedfromthecalibrationcurve.InordertoaccountforallofthestatisticalerrorsintheJEN-3measurementprocess,theminimumacceptablelevelofboronforanysheetwasestablishedas1.74%.Thisminimumlimitprovidesanadditionalmarginofsafetyinboronloading.With1.74%astheminimumacceptablecalculatedboronloading,thereisgreaterthan95%confidencethatnoBSSsheetscontainedlessthan1.70%boron.Thislevelofconfidenceprovidesamarginofsafetyinthecriticalitycalculations.NeutronattenuationdataofallBSSsheets,asmeasuredbyJEN-3atonerandomlyselectedlocationineachsheet,wasreviewedbyanindependentstatisticalconsultantretainedbyRG&E;JosephO.Voelkel,PhD.,Assistant U.S.NRCG.S.VidsingA-9October10,1997ProfessorofStatisticsattheCollegeofEngineering,RochesterInstituteofTechnology.Hisconclusions,basedonbothparametricandnon-parametrictoleranceintervals,confirmedtheacceptancecriteria,describedabove.3)BoronHomogeneity-Thirty-four(34)BSSsheetswererandomlychosenfromthetotalpopulation.Aneutronattenuationmeasurementwastakenatfive(5)randomlyselectedlocationsoneachsheetusingtheJEN-3device.ThissamplingplanwasinaccordancewiththeinstructionsofASTM-E826,"StandardPracticeforTestingHomogeneityofMaterialsfortheDevelopmentofReferenceMaterials."ThicknessmeasurementsweretakenattheexactlocationswheretheJEN-3measurementsweretaken.Thedatawerethenevaluatedbystatisticaltestsasfollows:Ranges(maximumminusminimummeasuredvalue)werecalculatedforeachofthe34setsof5JEN-3values.Thesewereplottedagainstthecalculatedmeanrangeand2-sigmavalues.Ifnovaluesfelloutsidethe2-sigmalimits,thiswouldbeoneindicationofhomogeneitywithinthepopulation.Thiswasindeedthecase;i.e.,allvalueswerewithin2-sigmalimits.AnalysisOfVarianceundertherandomeffectsmodelwasperformedonthedata.Residualmodeldiagnosticsdemonstratedarandomdistributionofresiduals,indicatinghomogeneityofborondistributionthroughouttheBSSpopulation.TheseresultsstronglyindicatehomogeneityofborondistributionthroughouttheBSSproduct.InsectionsandTestsPerformedbRochesterGasA,ElectricCo~ChemicalAnalysisOverchecks(Boroncontentbywetchemicalanalysis)ChemicalanalysisoverchecksonsamplesofBSSobtainedfromBOHLERwereperformedbytwoindependentcommercialtestinglaboratoriesintheUS.TheseanalyseswereobtainedtoprovideadditionalconfidenceintheboronanalysesreportedbyBOHLER.ResultsofthesetestsarepresentedinTable4.TheresultsofthetheseoverchecksindicatethattheboronanalysesreportedbyBOHLERarereliable.~MetallographicExaminations U,S.NRCG.S.VissingA-10October10,1997Samplescutfromonesheetfromeachlotofmaterialinboththeprincipalandtransverserollingdirectionswereexaminedmetallographically.AllspecimenswerepolishedandetchedwithKallingsreagent.Themicrostructuresinbothlongitudinalandtransversecross-sectionsexhibitafine,'niformdispersionofboridesinanausteniticmatrix.Noevidenceofbandingorsegregationarepresent.TheboridehomogeneityintheBOHLERmaterialcomparesveryfavorablywithpublishedmicrostructuresofGradeAmaterialproducedbypowderedmetallurgymethods'.ualitAssurance'OverihAdditionalinspectionswereprovidedaspartofQualityAssuranceoversight.BohleractivitiesweresubjecttoqualitysurveillancebypersonnelfromtheBohler,ATEA,FramatomeTechnologies,andRochesterGas&ElectricQualityAssuranceorganizations.ThisoversightprovidedindependentmonitoringoftheBSSmanufacturingprocessandresultsofinspectionactivitiesatBohler.~

Reference:

1.Smith,R.J.,Loomis,G.W.,Deltete,C.P.,BoratedStainle.sSteelAlicationinen-FuelStoraeRack.,EPRITR-100784,Project2813-21,FinalReport,June1992,p.3-13.

U.,S.NRCG.S.VissingA-11October10,1997TABLE1HeatAnalsesCSiMnPSCrNiBNC70780C70796B00021B04901ASTMA887TypeB6ASTMA887TypeB7.021.331.13.013,00119.8912.501.81.018.029.341.06.012.00119.9612.641.76.021.020.551.18.009.00219.6913.181.76.027.013.421.21.008.00119.5013.211.75.015.08'5'.0'45'3'8.012.01.510'20.015.01.740817512Pl045103l18P12Q1751PI20.015.02.25Note1:MaximumvalueTABLE2MechanicalProertiesH~eatL~otC70796290C70796314C70780287C70780282C70780313C70780288C70780289B00021221B00021223B04901224B04901222UTS~Y~EIonationHardness~SI~KSI~oin2"~Brinell94.766.412.319596.062.111.721999.165.312.220993.161.214.123994.755.310.622997.563.811.219995.956.716.823994.462.810.922497.261.812.222993.058.313.823495.366.112.3229ASTMA887-8975Min30Min6.0Min241Max U.S.NRCG.S.VissingA-12October10,1997TABLE3~d~CSiMnPSCrNiBNCB00021221B00021223B04901222B04901224C70780282C70780287C70780288C70780289C70780313C70796290C70796314.021.551.18.008.00319.713~1.020.009.431.21.007.00219.413~1.01.024.321.10.012.00119.812.4.023.023.023.023.025.331.06.012.00119.912.5.0251.75.0321.741.73.0161.761.76.0221.811,801.801.801.78.0281.78TABLE4BoronAnalsisOvercheck~Heat~SheetC70780105C70780105C70780105LaboratoryBohlerLedouxM&PLabs%Boron1.83%1.86%1.82%B0002191AB00021371AB0490111AB04901171ALedouxM8cPLabsLedouxMEcPLabs1.82%1.84%1.82%1.85%

U.S.NRCG.S.VilsingA-13October10,1997uestion¹4:AlthoughtestswithboratedstainlesssteelhaveindicatedthatintheSFPenvironmentnomeasurablecorrosiondegradationtakesplace,theimportanceofitsroleinreactivitycontrolintheSFPmakesitadvisabletohaveasurveillanceprogramwhichwouldprovideadditionalassurancethatatalltimestherewillbeenoughpoisonmaterialintheSFP.Areyouplanningtoinstitutesuchaprograniinyourplant?Ifso,describetheprogram.Ifnot,provideyourbasis.~Resense:RG&Eplanstoinstituteasurveillanceprogramforboratedstainlesssteel(BSS)intheSFPattheR.E.GinnaNuclearPowerStation.Acoupontreehasbeendesignedwhichconsistsof.a304Lstainlesssteelracktowhich36BSScoupons(8"longX6"wide)willbebolted.EachfaceandtheedgesofthecouponsareexposedtotheSFPboricacidenvironment.Crevicesand304L/BSSgalvaniccouplesarecreatedonthetreeateachboltlocation.ThecouponswereselectedsothatmaterialfromeachheatandlotofBSSsheetmaterialto,beusedaspoisonpanelsinthepoolarerepresentedonthetree.Incomparisonwithsurveillanceprogramsforotherneutronabsorbermaterials,thedesignandconstructionofthecoupontreefortheGinnaSFPprovidesamoreaccuraterepresentationoftheactualexposureconditionsofBSSintheSFP.Thetreewillberemovedandinspectedafterthefirst18-monthoperatingcycle,andeverythreeoperatingcycles(approximately41/2years)thereafter.Thecouponswillberemovedfromthetree,inspectedvisuallyforanyevidenceofcorrosion,andthicknessmeasurementstakenontheexposedsurfacesandinthecreviced/galvanicallycoupledareas.Thesemeasurementswillbecomparedwiththeoriginalthicknessmeasurementsrecordedforeachcoupontodetermineifanymeasurablemateriallosshasoccurred.Inaddition,eachcouponwillbeweighedandtheweightscomparedwithoriginalweightstodetermineweightchange.Anyunusualsurfaceconditionsuggestiveofsignificantcorrosionwillbeevaluatedusingappropriateanalyticalmethods.

1~slirCg-~I' sAU.S.NRCG.S.Vi~singA-14October10,1997uestion¹5:WithalargernumberoffuelassembliesstoredintheSFPitisexpectedthatmorecorrosionproductsandotherimpuritieswillbegeneratedintheSFP.Isthepresentlyexistingpurtftcationsystemadequatetohandlethisincreasedamountofimpurities?Provideyourbasis.Recense:Thecurrentpurificationsystemconsistsof:(a)astring-woundskimmerfilterforsurfacecleanliness,and(b)aspentfuelpoolmixedbedresinforliquidpurification.Theresinbedpullsfromthebottomofthepoolforitscleaningprocess.Itisa15cubicfootmixedbedresinfiltrationsystem.Thefrequencyofchange-outofthesurfacefiltrationsystemiscurrentlyapproximatelyonceeverytwoyears.Thisisasurfaceclaritymaintenancesystem.Theadditionalfuelwillnotaffectitsoperatingcharacteristics.Thefrequencyofchange-outfortheresinsystemiscurrentlyonceperyear.Historicalrecordsfollowingthe1985rerackprojectatGinnaStationshowednomeasurableincreaseinthechange-outfrequency.The1985changewaslargerinitsworkscopethantheproposedmodification.Atthattime,approximately420cellswereadded.Bycomparison,theproposedmodificationwillincreasethestoragecapacityby305cellsin1998(anadditional48storagecellsmaybeaddedinthefutureifneeded)~Itispostulatedthattheupcomingrerackwillnotincreasethecleaningsystemchange-out.However,thesystemwillbemonitoredtodetermineanychangestohistoricalpatterns.Thereforeitcanbeconcludedthatthecapacityofthepurificationsystemisadequateandcanabsorbtheadditionalstoragerequirementswithoutsubstantiallyaffectingcurrentplantmaintenancecapabilitytohandleanyincreasedamountofcorrosionproductsandotherimpurities.

01'I/'hJFP