ML17328A930

Criticality Analysis of DC Cook Nuclear Plant Fuel Racks Region 1 Checkerboard of Burned & Fresh Fuel Assemblies.

ML17328A930
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Issue date:	11/30/1990
From:	FECTEAU M W, KOVACIK W P, SIGNORELLA T L INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
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CRITICALITY ANALYSISOFTHEDONALDC.COOKNUCLEARPLANTFUELRACKSREGION1CHECKERBOARD OFBURNED&FRESHFUELASSEMBLIES November1990M.W.FecteauT.L.Signorella W.P.KovacikJ.R.SeekerF.K.Torres9102250099 9i02i5PDRADOCK050003i5PPDR

TABLEOFCONTENTS1.0Introduction 1.1DesignDescription 1.2DesignCriteria~~~~~~~1~\~~2.0Analytical Methods2.1Criticality Calculation Methodology 2.2Reactivity Equivalencing Methodology

~~3~~~~~~~~~43.0Criticality AnalysisofRegion1Checkerboard 3.1KENOReactivity Calculations 3.2PHOENIXReactivity Equivalencing 3.3Postulated Accidents 3.4Sensitivity Analysis4.0SummaryofCriticality ResultsArrangement

..........

6~~~~~~~~~6I'~~~~~~~r'~9~~~~~9~~~~~~~~~~~~~~~~~10Bibliography 25TableofContents LISTOFTABLESTableTableTableTableTable1.FuelParameters EmployedinCriticality Analysis2.Benchmark CriticalExperiments

[5,6]3.Comparison ofPHOENIXIsotopics Predictions toYankeeMeasurements 4.Benchmark CriticalExperiments PHOENIXComparison 5.DataforUMetalandUO~CriticalExperiments 1213Core5141516ListofTables 1p1',I LISTOFILIUSTRATIONS FigureFigureFigureFigureFigureFigureFigure1.DonaldC.CookNuclearPlantSpentFuelPoolStorageCellNominalDimensions

~~~1~2.DonaldC.CookNuclearPlantSFPRegion1Checkerboard FuelAssemblyLoadingSchematic 3.DonaldC.CookNuclearPlantSchematic forSFPInterface BoundaryBetweenRegions1and24.DonaldC.CookNuclearPlantSFPRegion1"Burned"FuelAssemblyMinimumBurnupvs.initialUEnrichment Curve5.Sensitivity ofk~<<toEnrichment intheDonaldC.CookNuclearPlantSFPRegion1StorageAreawithCheckerboard Loading6.Sensitivity ofke<<toCenter-to-Center SpacingintheDonaldC.CookNuclearPlantSFPRegion1StorageAreawithCheckerboard Loading7.Sensitivity ofke<<to8LoadingintheDonaldC.CookNuclearPlantSFPRegion1StorageAreawithCheckerboard Loading18192021222324ListofIllustrations L'CltgS,I5 1.0,INTRODUCTION Thisreportpresentstheresultsofacriticality analysisoftheDonaldC.CookNuclearPlantSpentFuelPool(SFP)storagerackforthestorageofWestinghouse andANF(Advanced NuclearFuel)15x15and17x17fuelassemblies, Thisanalysisconsiders acheckerboard arrangement ofburnedandfreshfuelassemblies withintheSFPRegion1area.IlsTheDonaldC.CookNuclearPlantSFPstoragerackwaspreviously analyzedforthestorageofWestinghouse 15x15and17x17fuelastwoseparatespentfuelarraysorregions.Region1wasanalyzedfornominalenrichments upto4.95w/oUusingathreeoutoffourfuelassemblystoragearrangement.

335Region2wasanalyzedfornominalenrichments upto3.95w/oUusingallavailable storagecells.Enrichments greaterthan3.95w/owerealsoallowed'ntheRegion2area,providedrestrictions onburnupweremet.Thisreportdescribes analternate fuelassemblystoragearrangement fortheRegion1areawhichutilizesallavailable storagelocations.

Thisarrangement regainsthetwenty-five percentstoragecelllossofthepreviousthreeoutoffourstoragearrangement, bycheckerboarding burnedandfreshfuelassemblies togetherwithinthesameregion.Burnupcredit,whichtakesintoconsideration thechangesinfuelandfissionproductinventory resulting fromdepletion inthereactorcore,willbeusedtoestablish theburnuprequirements oftheburnedfuelassemblies inthecheckerboard.

Thecriticality andburnupcreditanalysisofthecheckerboard arrangement ispresented inSection3ofthisreport.ThisDonaldC.CookNuclearPlantSFPcriticality analysisisbasedonmain-tainingkyar~50.95forstorageofWestinghouse 15x15STD(Standard) andOFA(Optimized FuelAssembly),

17x17STD,OFAandVANTAGE5,andANF15x15and17x17fuelassemblies.

Thefuelparameters relevanttothisanalysisaregiveninTable1onpage12.1.1DESIGNDESCRIPTION TheDonaldC.CookNuclearPlantSFPstoragecelldesignisdepictedsche-matically inFigure1onpage18withnominaldimensions givenonthefigure.TheRegion1checkerboard arrangement ofburnedandfreshfuelassemblies isshowninFigure2onpage19andanexampleoftheinterface boundarybe-Introduction

'1sElJ tweentheRegionicheckerboard andexistingRegion2storageareasisgiveninFigure3onpage20.ThetotalnumberofSFPlocations designated asRegion1or2islefttotheutilitytodetermine.

TheboundarybetweenthetworegionscanbedrawnanywherewithintheSFPracks,buttheinterface mustbeconfigured suchthatthereisaonerowcarryover ofthepatternestablished inRegion1intoRegion'.Thisassuresthatthepatternoffuelassemblies attheinterface willnotbemorereactivethanthepatternsallowedoneithersideoftheboundary.

Figure3onpage20illustrates.

theRegion1to2boundaryinterface.

Inthisfigure,thehorizontally-lined boxesrepresent Region1"fresh"fuelstoragelo-235cationswhicharequalified forfreshfuelenrichments upto5.0w/oU.Thediagonally-lined boxesrepresent Region1"burned"fuelstoragelocations whicharequalified forstorageoffuelassemblies whichsatisfytheRegion1burnup-enrichment requirements ofFigure4onpage21.Theblankboxes"rep-resentRegion2fuelassemblystoragelocations whicharequalified forstorageoffuelassemblies whichsatisfytheRegion2enrichment-burnup requirements asreportedinthepreviouscriticality report.Inthisfigure,thecheckerboard patternofRegion1burnedassemblies

{diagonally-lined boxes)hasbeencarriedintotheRegion2areabyonerow.Theremaining cellsinthefirstrowofRegion2arethenfilledwithfuelassemblies whichmeettherequirements forstorageinRegion2(blankboxes).Inthisway,therequirements forfuelas-semblystorageinbothregionsaresatisfied, andanygroupingoffourassem-bliesattheinterface boundarywillalwaysbelessthanorequalinreactivity tosimilargroupsoffourassemblies allowedoneithersideoftheboundary.

1.2DESIGNCRITERIACriticality offuelassemblies inafuelstoragerackisprevented bythedesignoftherackwhichlimitsfuelassemblyinteraction.

Thisisdonebyfixingtheminimumseparation betweenfuelassemblies andinserting neutronpoisonbe-tweenfuelassemblies.

Thedesignbasisforpreventing criticality outsidethereactoristhat,including uncertainties, thereisa95percentprobability ata95percentconfidence levelthattheeffective neutronmultiplication factor,kyar~,ofthefuelassemblyarraywillbelessthan0.95asrecommended byANSI.57.2-1983 andReference 2.Introduction

'IpL

2.0 ANALYTICAL

METHODS2.1CRITICALITY CALCULATION METHODOLOGY Thecriticality calculation methodandcross-section valuesareverifiedbycomparison withcriticalexperiment dataforfuelassemblies similartothoseforwhichtheracksaredesigned.

Thisbenchmarking dataissufficiently diversetoestablish thatthemethodbiasanduncertainty willapplytorackconditions whichincludestrongneutronabsorbers, largewatergapsandlowmoderator densities.

Thedesignmethodwhichinsuresthecriticality safetyoffuelassemblies inthespentfuelstoragerackusestheAMPX'ystemofcodesforcross-section generation andKENOIVforreactivity determination, The227energygroupcross-section librarythatisthecommonstartingpointforallcross-sections usedforthebenchmarks andthestoragerackisgenerated fromENDF/B-V'ata.

TheNITAWLprogramincludes, inthislibrary,theself-shielded resonance cross-sections thatareappropriate foreachparticular geometry.

TheNordheimIntegralTreatment isused.Energyandspatialweighting ofcross-sections isperformed bytheXSDRNPM'rogram whichisaone-dimensional S~transport theorycode.Thesemultigroup cross-section setsarethenusedasinputtoKENOIV'hichisathreedimensional MonteCarlotheoryprogramdesignedforreactivity calculations, Asetof33criticalexperiments hasbeenanalyzedusingtheabovemethodtodemonstrate itsapplicability tocriticality analysisandtoestablish themethodbiasanduncertainty.

Theexperiments rangefromwatermoderated, oxidefuelarraysseparated byvariousmaterials (B4C,steel,water,etc)thatsimulateLWR(LightWaterReactor)fuelshippingandstorageconditions todry,harderi7ispectrumuraniummetalcylinderarrayswithvariousinterspersed materials (Plexiglas andair)thatdemonstrate thewiderangeofapplicability ofthemethod.Table2onpage13summarizes theseexperiments.

Theaverageke~tofthebenchmarks is0.992.Thestandarddeviation ofthebiasvalueis0.0008bk.The95/95onesidedtolerance limitfactorfor33valuesis2.19.Thus,thereisa95percentprobability witha95percentconfidence levelthattheuncertainty inreactivity, duetothemethod,isnotgreaterthan0.0018Ik.Analytical Methods3 1rkAvI"IIII<s'll REACTIVITY EQUIVALENCING METHODOLOGY Spentfuelstorage,intheRegion1areaoftheDonaldC.CookNuclearPlantSFP,isachievable bymeansoftheconceptofreactivity equivalencing.

Theconceptofreactivity equivalencing ispredicated uponthereactivity decreaseassociated withfueldepletion, Aseriesofreactivity calculations isperformed togenerateasetofenrichment-fuel assemblydischarge burnuporderedpairswhichallyieldtheequivalent katewhenthefuelisstoredintheRegion1racks.Thedatapointsonthereactivity equivalence curvearegenerated withatrans-porttheorycomputercode,PHOENIX.PHOENIXisadepletable, two-dimensional, multigroup, discreteordinates, transport theorycode.A25energyi'0>groupnucleardatalibrarybasedonamodifiedversionoftheBritishWIMSlibraryisusedwithPHOENIX.Astudywasdonetoexaminefuelreactivity asafunctionoftimefollowing discharge fromthereactor.Fissionproductdecaywasaccounted forusingCINDER'CINDERisapoint-depletion computercodeusedtodetermine fissionproductactivities.

Thefissionproductswerepermitted todecayfor30yearsafterdischarge.

Thefuelreactivity wasfoundtoreachamaximumatapprox-imately100hoursafterdischarge.

Atthistime,themajorfissionproductpoison,Xe,hasnearlycompletely decayedaway.Furthermore.

thefuelre-activitywasfoundtodecreasecontinuously from100hoursto30yearsfol-lowingdischaige.

Therefore, the'mostreactivetimeforafuelassemblyafterdischarge fromthereactorcanbeconservatively approximated byremovingtheXThePHOENIXcodehasbeenvalidated bycomparisons withexperiments wheretheisotopicfuelcomposition hasbeenexaminedfollowing discharge fromareactor.Inaddition, anextensive setofbenchmark criticalexperiments hasbeenanalyzedwithPHOENIX.Comparisons betweenmeasuredandpredicted uraniumandplutonium isotopicfuelcompositions areshowninTable3onpage14.Themeasurements weremadeonfueldischarged fromYankeeCore5ThedatainTable3onpage14showsthattheagreement betweenPHOENIXpredictions andmeasuredisotopiccompositions isgood.Theagreement betweenreactivities computedwithPHOENIXandtheresultsof81criticalbenchmark experiments issummarized inTable4onpage15.Keyparameters describing eachofthe81experiments aregiveninTable5onpage16,Thesereactivity comparisons againshowgoodagreement betweenexper-imentandPHOENIXcalculations.

Sincetheburnuphistoryoffuelassemblies whichwillbedischarged inthefutureisnotknownexactly,areactivity uncertainty isappliedtotheburnup-dependent reactivities computedwithPHOENIX.Anuncertainty whichincreases linearlywithburnupto0.014kat30,000MWD/MTUisappliedtothePHOENIXcalculational resultsinthedevelopment oftheRegion1burnuprequirements.

Analytical Methods 1p0 Thisuncertainty isconsidered tobeveryconservative andisbasedoncon-sideration ofthegoodagreement betweenPHOENIXpredictions andmeasure-ments(comparison resultswiththeYankeeCoreexperiments andS1benchmark experiments aregiveninTable3onpage14andTable4onpage15)andonconservative estimates offuelassemblyisotopicbuildupvariances.

FortheDonaldC.CookNuclearPlantSFPRegion1analysis, thePHOENIXcalculations forthemaximumburnupof31,000MWD/MTUincludeareactivity uncertainty of0.0103Dk.Analytical Methods5 C3I,l~>V,J(A+

3.0 CRITICALITY

ANALYSISOFREGION1CHECKERBOARD ARRANGEMENT Thissectiondevelopsanddescribes theanalytical techniques andmodelsem-.ployedtoperformthecriticality andreactivity equivalencing analysisforstor-ageoffuelintheDonaldC.CookNuclearPlantSpentFuelPool(SFP)Region1area.Thisanalysisconsiders acheckerboard arrangement ofburnedandfreshfuelassemblies withintheSFPRegion1area.Section3,1describes theKENOreactivity calculations forthecheckerboard ar-rangement ofburnedandfreshfuelassemblies.

FortheKENOanalysis, the"burned"fuelassemblies willberepresented byfreshfuelassemblies withalowenrichment.

Section3.2willthendescribethePHOENIXreactivity equiv-alencinganalysiswhichwillestablish theburnuprequirements ofthe"burned"fuelassemblies inthecheckerboard.

Section3.3willdiscusspostulated acci-dentsandSection3.4willpresenttheresultsofthePHOENIXsensitivity cal-culations forenrichment, cellcenter-to-center spacing,andpoisonloading,3.tKENOREACTIVITY CALCULATIONS Thefollowing assumptions areusedtodevelopthenominalcaseKENOmodelforcheckerboard storageofburnedandfreshfuelassemblies in,theRegion1area(refertoFigure2onpage19forlayout).1.Westinghouse 17x17OFAfuelassemblies withnominalenrichments of5.0w/oUare.modelledinthe"fresh"fuelstoragelocations ofthecheck-erboard.Theenrichment of5.0w/oUwaschosentoconservatively boundallpresentandfuturefuelassemblyenrichments.

Evaluation oftheWestinghouse 15x15"and17x17andANF15x15and17xl7fuelassemblies showsthattheWestinghouse 17x17OFAfuelassemblyisthemostreactivefueltypeatthisenrichment.

TheWestinghouse 17x17VANTAGE5fueldesignparameters relevanttothecriticality analysisarethesameastheOFAparameters andwillyieldequivalent results.Therefore, onlytheWestinghouse 17x17OFA'uelassemblyisanalyzedinthe"fresh"fuelcheckerboard locations (seeTable1onpage12forfuelparameters).

2.Westinghouse 17xl7STDfuel'assemblies withnominalenrichments of2.3w/oUaremodelledinthe"burned"fuelstoragelocations ofthecheck-erboard.Evaluation oftheWestinghouse 15x15and17x17andANF15xl5Criticality AnalysisofRegion1Checkerboard Arrangement

and17x17fuelassemblies showsthattheWestinghouse 17x17STDfuelassemblyismorereactivethanotherWestinghouse 17xl7andANF15x15and17x17fueltypesandapproximately equivalent (within0.0015hk)totheWestinghouse 15x15fuelassemblyatthisenrichment.

Therefore, onlytheWestinghouse 17x17STDfuelassemblyisanalyzedinthe"burned"fuelcheckerboard locations (seeTable1onpage12forfuelparameters).

3.Allfuelassemblies containthehighestauthorized enrichment overthefinite144inchlengthofeachrod,areatthemostreactivepointinlife,andnocreditistakenforanyburnableabsorberinthefuelrodsoranynaturalenrichment axialblankets.

Theseassumptions resultinconservative calcu-lationsofreactivity.

4.Thefuelpelletsareassumedtobeat96%oftheoretical density,andnocreditistakenfordishingorchamfering.

5.NocreditistakenforanyUorUinthefuel,norisanycredittakenforthebuildupoffissionproductpoisonmaterial.

6.Themoderator ispurewateratatemperature of68'F.A-conservative valueof1.0gm/cmisusedforthedensityofwater.7.Nocreditistakenforanyspacergridsorspacersleeves.8.Allavailable fuelcellsareutilized.

Fuelassemblies arearrangedinacheckerboard pattern,asdepictedinFigure2onpage19.9.Thearrayisinfiniteinlateralextentandfiniteinaxialextentwhichallowsneutronleakagefromonlytheaxialdirection.

10.Theminimumpoisonmaterialloadingof0.02grams8persquarecenti-meterisusedthroughout thearray.TheKENOcalculation forthenominalcaseresultedinake<<of0.8932witha95percentprobability/95 percentconfidence leveluncertainty of+0.0045.Thenominalcaseresultcanbecomparedtothe'worstcaseresulttodetermine therelativeimpactofapplyingtheworstcaseassumptions.

Thenominalcaseisalsousedasthecenterpointforthesensitivity analysisdiscussed inSection3.4.Themaximumk~r~undernormalconditions arisesfromconsideration ofme-chanicalandmaterialthickness tolerances resulting fromthemanufacturing processinadditiontoasymmetric positioning offuelassemblies withinthestoragecells.Westinghouse internalstudiesofasymmetric positioning offuelassemblies withinthestoragecellshaveshownthatsymmetrically placedfuelassemblies yieldequalorconservative resultsinrackke<<.Thesheetmetaltolerances areconsidered alongwithconstruction tolerances relatedtothecellI.D.,andcellcenter-to-center spacing.FortheRegion1racks.thisresultsinthereduction ofthenominalcentertocenterspacings.to theirminimumvalues.Criticality AnalysisotRegion1Checkeiboard Arrangement 8t 23sFurthermore, fuelenrichments areincreased by0.05w/oUtoconservatively accountforenrichment variability.

Enrichments areassumedtobe5.05w/oUforthe"fresh"fuelcellsand2.35wloUforthe"burned"fuelcells.Thus,the"worstcase"KENOmodeloftheRegion1storagerackscontainsminimumcentertocenterspacings, symmetrically placedfuelassemblies, andmaximumfuelassemblyenrichments.

Basedontheanalysisdescribed above,thefollowing equationisusedtode-velopthemaximumkettfortheDonaldC.CookNuclearPlantSFPRegion1racks:kett=kworst~Bmetrtoo~Boert~Besml[(ks)worst~(ks)'metrtoo

]where:kwarstworstcaseKENOke<<thatincludesmaterialtolerances, andmechanical tolerances whichcanresultinspacingsbetweenfuelassemblies lessthannominalBmethoo=methodbiasdetermined frombenchmark criticalcomparisons BpertBesmbiastoaccountforpoisonparticleself-shielding.

Thisstandardtermaccountsfortheincreased neutrontransmission throughthepoisonplateduetotheinherenteffectsofpoisonparticleself-shielding, andhasbeenanalytically determined forpoisonplatessimilartothoseusedinthisanalysis.

biastoaccountforthereactivity difference betweentheRegion1SFP"burned"checkerboard locations loadedwithWestinghouse 17x17STDfuelassemblies at2.3w/oU'ersusWestinghouse 15x15fuelassemblies at2.3w/oUksworst=95/95uncertainty intheworstcaseKENO.ke<<ksmettoo=95/95uncertainty inthemethodbiasSubstituting calculated valuesintheorderlistedabove,theresultis:kett=0.9295+0.0083+0.0014+0.0015+l[(0.0044) i(0.0018)]=0.9455Sinceketfislessthan0.95including uncertainties ata95/95probability/confidence level,theacceptance criteriaforcriticality ismetfortheRegion1checkerboard arrangement of"fresh"fuelcellsatanominalenrichment of5.0w/oUand"burned"fuelcellsatanominalenrichment of2.3w/oU235Criticality AnalysisofRegion1Checkerboard Arrangement

\IIIIt 3.2PHOENIXREACTIVITY EQUIVALENC!NG Spentfuelstorage.intheRegion1checkerboard area,isachievable bymeansoftheconceptofreactivity equivalencing.

Theconceptofreactivity equiv-alencingispredicated uponthereactivity decreaseassociated withfuelde-pletion.Aseriesofreactivity calculations areperformed togenerateasetofenrichment-fuel assemblydischarge burnuporderedpairswhichallyieldtheequivalent ke<<whenthefuelisstoredintheRegion1"burned"fuelstoragecells.Themaximumk~<<forstorageofspentfuelintheRegion1checkerboard areaisdetermined usingthemethodsdescribed inSection2.Figure4onpage21represents combinations offuelenrichment anddischarge burnupyieldingthesamerackmultiplication factor(ki<<)astherackloadedwitha"checkerboard of5.0w/oUfuelinthe"fresh"fuelcellsand2.3w/oUfuel(atzeroburnup)inthe"burned"fuelcells.Thiscurvewasobtainedbyfirstcalculating theequivalent reactivity pointsusingPHOENIXandthennormalizing thepointstothenominalKENOcalculation described inSection3.1~Theuncertainty associ-atedwiththereactivity equivalence methodology isincludedinthedevelopment oftheburnuprequirements.

Thisuncertainty wasdiscussed inSection2.2.Figure4onpage21showstheconstantke<<contour generated fortheDonaldC.CookNuclearPlantRegion1checkerboard.

NoteinFigure4onpage21theendpointat0,MWD/MTUwheretheenrichment is2.3w/o,andat31,000MWD/MTUwheretheenrichment is5.0w/o.Theinterpretation oftheendpointdataisasfollows:thereactivity oftheRegion1checkerboard rackcontaining 5.0w/oUfuelatzeroburnupinthe"fresh"fuelcellsand5.0w/oUfuelat31,000MWD/MTUburnupinthe"burned"fuelcellsisequivalent tothere-235activityoftheRegion1checkerboard rackcontaining 5.0w/oUfuelatzeroburnupinthe"fresh"fuelcellsand2.3w/oUfuelatzerobur'nupinthe"burned"fuelcells.Itisimportant torecognize thatthecurveinFigure4onpage21isbasedonaconstantrackreactivity forthatregionandnotonaconstantfuelassemblyreactivity.

Inthisway,theenvironment ofthestoragerackanditsinfluence onassemblyreactivity isimplicitly considered.

3.3POSTULATED ACCIDENTS Mostaccidentconditions willnotresultinanincreaseinke<<oftherack.Ex-amplesarethelossofcoolingsystems(reactivity decreases withdecreasing waterdensity)anddroppingafuelassemblyontopoftherack(therackstructure pertinent forcriticality's notexcessively deformedandthedroppedfuelassemblyhasmorethantwelveinchesofwaterseparating itfromtheactivefuelheightofstoredfuelassemblies whichprecludes interaction).

However,accidents canbepostulated whichwouldincreasereactivity (i.e.,misloading afuelassemblywithaburnupandenrichment combination outsideCriticality AnalysisofRegion1Checkerboard Arrangement If oftheacceptable areainFigure4onpage21,ordroppingafuelassemblybetweentherackandpoolwall).Fortheseaccidentconditions, thedoublecontingency principle ofANSIN16.1-1975 isapplied.Thisstatesthatoneisnotrequiredtoassumetwo-unlikely, independent, con'current eventstoensureprotection againstacriticality accident.

Thus,foraccidentconditions, thepresenceofsolubleboroninthestoragepoolwatercanbeassumedasare-alisticinitialcondition sincenotassumingitspresencewouldbeasecondun-likelyevent,Thepresenceofapproximately 2000ppmboroninthepoolwaterwilldecreasereactivity byabout0.25Dk.Inperspective, thisisaboutfivetimesmorenegativereactivity thancouldbeaddedifeverycellintheSFPwerefilledwithfresh5.0w/oUfuelassemblies.

Thus,forpostulated accidents, shouldtherebeareactivity

increase, ki<<wouldbelessthanorequalto0.95duetotheeffectofthedissolved boron.SincetheDonaldC.'ookNuclearPlantSFPwillbemaintained ataboronconcentration of2400ppm,additional marginwillexisttothe0.95limit.3.4SENSITIVITY ANALYSISToshowthedependence ofke<<onfuelandstoragecellsparameters asre-questedbytheNRC,thevariation oftheke<<withrespecttothefollowing parameters wasdeveloped usingthePHOENIXcomputercode:1.Fuelenrichment, witha0.50w/oUdeltaaboutthepominalcaseenrichment.

Forthissensitivity, boththe"fresh"and"burned"fuelas-semblyenrichments wereadjustedsimultaneously.

2.Center-to-center spacingofstoragecells,withahalfinchdeltaaboutthenominalcasecenter-to-center spacing.3.Poisonloading,witha0.01gm-B/cmdeltaaboutthenominalcasepoisonloading.Resultsofthesensitivity analysisfortheRegion1checkerboard storagear-rangement areshowninFigure5onpage22throughFigure7onpage24.Criticality AnalysisofRegion1Checkerboard Arrangement 10 oI'VPP0g+

4.0 SUMMARYOFCRITICALITY

RESULTSTheacceptance criteriaforcriticality requirestheeffective neutronmultipli-cationfactor,ka<<,tobelessthanorequalto0.95,including uncertainties, underallconditions forthestorageoffuelassemblies intheSpentFuelPool(SFP).Thisreportshowsthattheacceptance criteriaforcriticality ismetfortheDonaldC.CookNuclearPlantSpentFuelPool(SFP)Region1checkerboard ofburnedandfreshfuelassemblies.

Thisconclusion isvalidforthestorageofWestinghouse 15x15STDandQFA,and17x17STD,QFAandVANTAGE5,andANF15x15and17x17fuelassemblies withthefollowing nominalenrichment limits:SFPRegion1"Fresh"Fuel'5.0wloUSFPRegion1"Burned"Fuel<5.0w/oU,withburnuprestrictions givenbyFigure4onpage21Thecheckerboard arrangement tobeusedforthestorageofburnedandfreshfuelassemblies intheRegion1areaisshownonFigure2onpage19.Anexampleoftheinterface boundarybetweentheRegion1checkerboard andtheRegion2areaisgivenbyFigure3onpage20.Theanalytical methodsemployedhereinconformwithANSIN18.2-1973, "Nu-clearSafetyCriteriafortheDesignofStationary Pressurized WaterReactorPlants,"Section5,7,FuelHandlingSystem;ANSI57.2-1983, "DesignObjectives forLWRSpentFuelStorageFacilities atNuclearPowerStations,"

Section6.4.2;ANSIN16,9-1975, "Validation ofCalculational MethodsforNuclearCriticality Safety";andwiththeNRCStandardReviewPlan,Section9.1.2,"SpentFuelStorage."

SummaryofCriticality Results hTable1.fuelParameters EmployedinCriticality AnalysisPARAMETER WSTO/OFAWOFA/V5WSTD15x1517x1717x17ANF15x15ANF17xl7NumberofFuelRodsperAssemblyRodZirc-4CladO.D,(inch)CladThickness (inch)FuelPei.letO.D.(inch)FuelPelletDensity(%ofTheoretical) 2040.4220.02430.3659962640.3600.02250.3088962640,3740.02550.3225962040.4240.03000.3565962640.3600.02500.303096FuelPelletDishingFactor(%)RodPitch(inch)NumberofGuideTubesGuideTubeO.D.(inch)GuideTubeThickness (inch)0.00,563200.5330.0170.00.496240.4740.0160.00.496240.4820.0160.00.563200.5450.0170.00.496240.4800.016NumberofInstrument TubesInstrument TubeO.D.(inch)Instrument TubeThickness (inch)0.5330.0170.4740.0160.48-20.0160.5450.0170.4800.01612

)p4'ltE, Table2.Benchmark CriticalExperiments

[5,6]GeneralOescrIptionSnrIcheentv/oU235Rei'lector SeparatIng liaterIaISolubI~BoronpixIKeir1.U02rod2.U02rod3.V02rod4.U02rod5.V02rod6.U02rod7.U02rod8.V02rod9.U02rod10.U02rod11.U02rod12.U02rod13.U02rod14.U02rod15.U02rod16.U02rod17.U02rod18.U02rod19.U02rod20.U02rod21.U02rod22.Ueetai23.Umetal24.Uraetal25.Ueetal26.Uaetai27.Ueetal28.Uraetai29.Vrectal30.Uaeta131.Uraetai32.Uoctal33.UraetallatticelettlcelettIcelettIcelattIcelatticelatttcelattice1atticelatticelatticelatticelaitlcelettice1atticelattice1attIcelatticelatticelatticeIattIcecyIinderscylinders cylInders cy1Inderscylinders cylinders cylInders cylinders cylinders cylinderscyIinderscy'IInders2.462.462.462.462.462.462.462.462.462.462.462.462.462.462.462.462.462.462'62.462.4693.293.293.293.293.293.293.293.293.293.293.2.93'watervaterwaterwaterwet~Iwaterwaterwaterwa't~rwaterwaterwaterwaterwaterwatervaterwaterwater~sterwa't~rwat~rbarebarebarebar~barebar~bareparerflnbareparaf'fInparaftinpara'lrInvaterwaterwater84Cpins84Cpins84Cpins84Cpins84Cpinswaterwaterstainless steelstainless steelberatedaluNInuaborateda1unlnueboratedaluminumboretedaluxinueboratedaluminumboratedaluoinunboraCedaiueinueboratedaluminumboratedalureinueaIrairairairairairplexig1assplexiglass plexiglasspIexig1assplexigIassplexiglass 01037764000000143514217159239512148719763432072000000000000+/-+/-0.98570.99060.98960.99140.98910.99550.98890.99830.99310.99280.99670.9943+/'/-+/>>+/-+/-+/y/>>y/>>+/-+/>>+/>>y/>>+/-+/-+/-+/-+/y/>>+/-+/+/-+/-+/-+/-0.98920.98840.98320.98480.98950.98850.99210.99200.99390.99050.99760.99470.99280.99220.9950+/-0.9941+/-0.9928+/-0.9968+/1.0042+/-0.9963+/-0.9919+/.0028.0018.0015.'0025.0026.0020.0027.0025.0028.0025.0020.0019.0023.0023.0021.0024.0020.0022.0019.0020.0020.0020.0020.0025.00'19.0026.0027.0030.0041.0018.0019.0030.003213 I

Table3.CornparisonofPHOENIXIsotopics Predictions toYankeeCore5Measurements Quantity(AtomRatio)U235/UU236/UU238/UPu239/UPu2,40/UPu241/UPu242/UPu239/U238 Mass(Pu/U)

FISS-PU/TOT-PU

%Difference

-0.67-0.28-0.03~3o27+3.63-7.01,-0.203.24~1.41-0.0214

~~

Table4.Benchmark CriticalExperiments PHOENIXComparison Description ofExperiments NumberofExperiments PHOENIXketchUsingExperiment Sucklings UOtAIcladSScladBoratedH~OSubtotal1419400.99470.99440.99400.9944U-MetalAlcladTOTAL41811.00120.997815 Table5.pataforIJMetalandUO$CriticalExperiments (PartlOf2)CaaeNuaberCellTypeA/0H20/UU-2'35rlatloFuelOenalty(a/CC)Pellet01aaeter(CM)Mater1~1C1adCladClad00Tlllckneaa (Cli)(CM)LatticeP1tcn(CM)BoronPPM123456789101112131415161718192021222324252627282930313233343837383940414243HexaHexaHexaHexaHexaHexaHexaHexaSquare5quareSquar~SquareSquareSquare5quareSquareSquareSquareSquareSquareSquareSquareSquareSquareSquareSquar~Squar~5quar~5quareSquar~SquareSquareSquareSquar~SquareHexaHexaHexaHexaHexaHexaHexaHexa1.3281.3281.32d1.3281.32S1.32d1.3281.3282.7342.7342.7342.7342.7342.7342.7342.7343.7453.7453.7453.7453.7453.7453.7453.7454.0694.0694.0692.4903.0373.0374.0694.0694.0694.O692.4902.0962.0962.0962.0962.0961.3071.3071.3073.023.954.953.924.892.883.584.832.182.923.867.028.4910.3$2.504.5$2.504.514.514.514.5$4.5$4.514.512.552.552.142.842.648.162.593.538.029.902.842.063.094.128.148.201.011.512.027.537.537'37.527.5210.5310.5310.5310.1$10.1810.1810.1810.1810.1810.1810.1810.2710.3710.3710.37$0.3710.3710.3710.379.469.469.4610.249.289.289.459.459.459.4510.2410.3810.38$0.3810.3$10.3818.9018.90lb.901.52651.52651.5265.9855.9S55.9728.9728.9728.7620.7620.7620.7620.7620.7620.7620.7620.7544.7544.7544.7544,7544.7544.7'544.75441.12781.$2781.12781.02971.12681.12681.12681.12681.12681.12681.02971.52401.52401.52401.52401.52401.52401.52401.5240A1ua1nuhAluh1nuaAluh1nuaAluh1nuaA1uh1nuhAluri1nuaAluh1nuaAIuri1nua55-30455-30455-30455-30455-30455-30455-30455-30455-30455-30455-30455-30455-30455-30455-30455-30455-30455-30455-304A1uh1nuh55-30455-30455-30455-30455-30455-304Aluh1nuaA1uh1nuaA1uh1nuhAlure1nuhAluhlnuaAIuri1nuaAluri1nuaAlualnuaAlua1nua1.69161.69161.69161.$5061.15061.15061.15061.1506".8594.$594.8594.8594.S594.8594.B594.8594:e600.8600:eeoo.$600.8600.8600.8600.86001.20901.20901.20901.20601.17011.27011.27011.27011.27011.270$1.20601.69161.,69$61.69161.69161.69161.69161.6916.1.6916.07110.07110.07110~07110.071$0.07110.07110.07110.04085.04085.04085.04085.04085.04085.04085.04085.04060.04060.04060.04060.04060.04060.04060.04060.04060.04060.04060.08130.07163.07163.07163.07163.07163.07163.08130.07112.07112.07112.07112.071$2.07112.07112.071122'0502.35902.51201~55801.6520'I.55801.65201.80601.02871.10491.19381.45541.56211.68911.06171.25221,.06$71.25221.2522$.25221.25221.25221.25221.2522$.51131.51131.45001.51131.55502.19801.55501.68402.19802.38101.51132.17372.40522.61622.98913.32552.17422.40542.61620.00.00.00.00.00~00.00.00.00.00.00.00.00.00~00,00~00.00.0456.0709.01260.01334~01477.00.03392.00.00.00.00.00.00.00.00.01677.00.00.00.00.00.00.0000.0'6

Table5.DataforUMetalandUO>CriticalExperiments (part20f2)CaseCol)NuraberTypeFue)PelletA/0H20/UDensityDiameterU-235Ratio(6/CC)(CM)CIactMaterialOQClad(CM)CIadLatticeThickness Pitch.Boron(CM)(CM)PPM44454647484950515253545556575859606162636465666768697071727'37475767778798081HexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexaHexa1.3071.307t.1601.1601.1601.1601.1601.0401.0401.0401.0401.0401.3071.3071.3071.3071.307t.f601.1601.1601.160t.1601.1601.1601.160S.1601.0401.0401.0401.040I.0401.0401.3101.3101.1591.1591.3121.3123.0118.904.0218.901.0118.901.5118.902.02'8.903.0118.904.0218.901.0118.901.5118.902.0218.903.0118.904.0218.901.0018.901.52i8.902.0218.903.02t8.904.0218.90t.5218.902.0218.903.02tS.904.0218.90t.QQ)$.901.5218.902.0218.903.0218.904.02,18.901.3318.901.5S18.901.8318.902.3318.902.8318.903.8318.902.0218.883.0118.882.02f8.883.0118.882.0318.883.0218.881.52401.52401.52401.52401.52401.52401.52401.52401.52401;52401.52401.5240.9830.9830.9830.9830.9830.9830.9830.9830.9830.9830.9830.9830.9830.983019.05019.05019.05019.05019.05019.05Q1.52401.52401.52401.5240'9830.9830AIuraInuraAIumInumAIum1numAIuraInumA)urninurnA)urnInurnAIura1rwmAluraIrwmAturn1rwraAluminumAIum1numAIum1rwraAluminumAIura1numAlum1numAluminurnA)urnInumAIumInurnAIum1numAluminumAlurainurnA)umtnumAIum1numAIum1numAIumInumAIuminumAIura1numAluminumAIurainurnAIuminumAlum1numAIuraInumA'Ium1numAIura1numA)umirwmA)um1numAlum1rwmAIuminum1.69161.69161.69161.69161.69161.69161.69161.69161.69161.69161.69161.69t61.1506t.f5061.1506.t.15061.1506t5061.1506f.15061.1506S.15061.15061.15061.15061.15062.05742.05742.05742.05742.05742.05741.69161.6916f.69161.69161~15061.1506.07112~07112.07112.07112.07112.07112.07112.OT112.07112~OTS12~07112.07112.07112.07112.07112.07)12.07112~07112.07112.07112.071t2.07112.OT112.07112.071t2.07112.07620.07620.07620.07620.07620.07620.07112'07112.07112.07112.07tt2.071122.98963.32492~17422,40542,61622.98963.32492.17422.40542.6I622.98963.32491.4412I.59261.72471.96092~1742I~59261.72471.96092~17421.44121.59261.724796092~17422.86873'0863.1425'.3942 3.62844'5662.61602.99002~61602'9900I.72501.96100.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.00.0QQ0.00.00.017 lfPr SEEDETAILA8.884"0.196"1.224"CELLCENIERIOCEMIER(10.5"t.03"Stainless steel~.Ot"At07l"B,C-AIgPRAL~.otAt075"Stainless SteelDETAILAINSIDEOFCELLFigure1.OonaldC.CookNuclearPlantSpentFuelPoolStorageCellNominalOimensions IPP RegionIFreehFuelRegionIBurnedFuelFigure2.DonaldC,CookNuclearPlantSFPRegion1Checkerboard FuelAs-semblyLoadingSchematic t'I IIII(IIRegion1to2Boundaryon1Region2RegionlFreshFue1Reg1onIBurnedFuelRegion2BurnedFuelFigure3.DonaldC.CookNuclearPlantSchematic forSFPinterface BoundaryBetweenRegions1and220

~wj's>IAE 32302826~24C52220DIIIIACCEPTABLEIILI18w16IIIIIIIIIV)o12I1TII~108IIJLINOTACCIIEPTABLEIITI2.32.52.72.93.13.3)53.53.73.94.14.34.54.74.95.1Uc35ENRlCHMENT (I/O)Figure4.DonaldC.CookNuclearPlantSFPRegion1"Burned"FuelAssemblyMinimumBurnupvs.initialUEnrichment Curve21 1~AI'gI'e

'.92.91.90III.88III.87).554.251.804.502.05'.302.554.755.005.25UENRICHMENT (W/0)2.803.055.505.758ORALHELDAT.02GMB/CMCENTERTOCENTERHELDAT10.50"Figure5.Sensitivity ofkerftoEnrichment intheDonaldC.CookNuclearPlantSFPRegion1StorageAreawithCheckerboard Loading22

.92.91IIIIIIII.89.88IIIIIIIIII.8f.8010.010.210.410.610.8CENTER-TO-CENTER SPACING(INCHES)11.011.2BORALHELDAT.02GMB/CMCHECKERBOARD ENRICHMENT HELDAT2.3/5.0W/0Figure6.Sensitivity ofke<<toCenter-to-Center SpacingintheDonaldC.CookNuclearPlantSFPRegion1StorageAreawithCheckerboard Loading23 1y'A

.910905II-I-IIIIIIIIIIIIII-+-IIIIII1-III-.900II-I-IIIIIIIItII+III-III-III890II-I-IIt-II-t-III-IIt.885IIIIII880.008.010.012.014.016.018.020.022.924.026POISONLOAD(GM8Iv/CM)028.030.032CENTERTOCENTERHELDAT10.50"CHECKERBOARD ENRICHMENT HELDAT2.3/5.0W/0Figure7.Sensitivity ofkenttoBLoadingintheDonaldC,CookNuclearPlantSFPRegion1StorageAreawithCheckerboard Loading24 4pVSpy1l BIBLIOGRAPHY1.W.A.Boyd,et.al.,Criticality AnalysisoftheDonaldC.CookNuclearPlant,FuelRacksOctober 1989.2.NuclearRegulatory Commission, LettertoAllPowerReactorLicensees, fromB.K.GrimesOTPositionforReviewandAcceptance ofSpentFuelStorageandHandlingApplicationsApril 14,1978.3.W.E,Ford-III,CSRL-V:Processed ENOFIB-V227-Neutron-Group andPointwise Cross-Section Libraries forCriticality Safety,ReactorandShielding Studies,ORNLICSOITM-160, June1982.4,N.M.Greene,AMPX:AModularCodeSystemforGenerating Coupled~MultigroupNeutron-Gamma LibrariesfromENOFIB,ORNL/TM-3706, March1976.5,L.M.PetrieandN.F.Cross,KENOIV--AnImprovedMonteCarloCriticality Program,ORNL-4938, November1975.6.M.N.Baldwin,CriticalExperiments Supporting CloseProximity WaterStorageofPowerReactorFuel,BAW-1484-7, July1979.t7.J.T.Thomas,CriticalThree-Dimensional ArraysofU(93.2JMetalCylinders, NuclearScienceandEngineering, Volume52,pages350-359,1973.8.D.E.Mueller.W.A.Boyd,andM.W,Fecteau(Westinghouse NFD),Qualification ofKENOCalculations withENDFIB-VCrossSections, AmericanNuclearSocietyTransactions, Volume56,pages321-323,June1988.9.A.J.Harris,ADescription oftheNuclearDesignandAnalysisProgramsforBoilingWaterReactors, WCAP-10106, June1982.10.Askew,J.R.,Fayers,F.J.,andKemshell, P.B.,AGeneralDescription oftheLatticeCodeWINS,JournalofBritishNuclearEnergySociety,5,pp.564-584,1966.11.England,T.R.,ClNOER-AOne-Point OepletionandFissionProductProgram,WAPD-TM-334, August1962.12.Melehan,J.B.,YankeeCoreEvaluationProgramFinal'eport,WCAP-3017-6094, January1971.Bibliography 25

ATTACHMENT 2TOAEP:NRC:1071N DESCRIPTION OFPROPOSEDT/SsCHANGESAND10CFR50.92SIGNIFICANT HAZARDSCONSIDERATION ANALYSIS

'srtE;~wJP~t Attachment 2toAEP:NRC:1071N Page1Introduction Thisletterrequests, T/Sschangesinthestoragepatterninthespentfuelpool.Thechanges'involveSection5(DesignSection)andarebasedoncriticality andthermal-hydrauli'c concerns.

Asdiscussed laterinthisattachment,'nalyses havebeenperformed thatdemonstrate theacceptability oftheproposedT/Sschangeswithregardtothecriticality concerns.

Wehavealsoconcluded thatthecurrentanalysisofrecordforthethermal-hydraulic concernsremainsbounding.

DescritionofChanesTheproposedT/Sschangesareasfollows:1)InUnits1and2T/S5.6.1.1,subparagraph c.lhasbeenmodified, theexistingsubparagraph c.2hasbeenslightlymodifiedandrenumbered asc.3,andanewsubparagraph c.2hasbeenadded.2)Subparagraph c.lidentifies "Region1"ofthespentfuelstorageracksforstorageofWestinghouse fueltypeswithmaximumnominalfuelassemblyenrichments of3.95weightpercentorgreater.FuelstoredinRegion1mustbestoredinacheckerboard configuration alternating Westinghouse Category1andCategory2fuel,asshowninFigure5.6-1(seeAttachment 1,Figure3).Category1fuelisdefinedasWestinghouse fuelshowninFigure5.6-2as"acceptable forstorageasCategory1fuel."Category2fuelisdefinedasWestinghouse fuelwithanenrichment greaterthan3.95weightpercentU-235andaburnuplessthan5,550MWD/MTUshownontheshadedareaofFigure5.6-2.Thesearethemaximumenrichments andminimumburnupsforWestinghouse fuelthatcanbestoredinRegion2,asdiscussed inthenextparagraph.

3)Thenewsubparagraph c.2identifies "Region2"ofthespentfuelstorageracks.ThisRegion2shallbefor-thestorageofWestinghouse fuelwithanenrichment 1essthanorequalto3.95weightpercentU-235orwithanenrichment greaterthan3.95weightpercentU-235butwithaburnupgreaterthanorequalto5,550MWD/MTU,andExxon/ANF fuelofanenrichment lessthanorequalto4.23weightpercentU-235fora17x17assemblyorlessthanor,equa'1 to3.50weightpercentU-235fora15x15assembly.

Themaximumenrichment andminimumburnuplimitsforWestinghouse fuelthatcanbestoredinRegion2werejustified inourprevioussubmittal AEP:NRC:1071F.

0 Attachment 2toAEP:NRC:1071N Page24)Theexistingsubparagraph c.2isrenumbered asc.3andisbeingmodifiedslightlytoaddresstheboundarycondition betweenRegions1and2.Thisboundarycondition isthatthecheckerboard patternrequirement forRegion1mustbecarriedintoRegion2byatleastonerow.Thisboundarycondition isillustrated intherevisedfigure,Figure5.6-1.5)ThesecondpageofTable5.7-1intheUnit2T/Ssisincorrectly labeledasTable5.9-1.Thishasbeenrevised.Beingpurelyeditorial, thischangeisnotdiscussed inthesignificant hazardsconsideration portionofthisattachment.

SummarofCriticalit AnalsesAttachment 1containscriticality analysesforRegion1ofthespentfuelpoolandfortheboundarybetweenRegions1and2,preparedforusbyWestinghouse.

Theanalyseswereperformed insuchawaythattheyboundalltypesofWestinghouse fuelcurrently inuseorplannedforuseintheCookNuclearPlant.Inaccordance withtheacceptance criteriaofChapter9.1.2(SpentFuelStorage)oftheNRCStandardReviewPlan,theWestinghouse analysesdemonstrate thatthecenter-to-center spacingbetweenfuelassemblies andanystrong,fixedneutronabsorbers inthestorage,racksaresufficient tomaintainthearray,whenloadedwithfuelassemblies withamaximumnominalenrichment of4.95weightpercentU-235andfloodedwithpurewater,inasubcritical condition withkfflessthan0.95.Inordertoachieveacceptable results,Westinghouse hasdetermined thatfreshfuelassemblies withnominaleff.enrichments above3.95weightpercentU-235mustbestoredinRegion1ofthespentfuelstorageracksinacheckerboard patternconfiguration alternating Category1andCategory2fuel.Inaddition, thischeckerboard patternofRegion1mustbecarriedintoRegion2byatleastonerow.Itshouldalsobepointedoutthatonefuelassembly, whichhasanenrichment largerthan4.55weightpercentU-235,wouldhaveakfflargerthan0.95whenoutof'hepoisonedracksandwith0ppmofboroninthespentfuelpool.However,itcanbeshownthatwithonly1000ppmofboron,thekofafuelassemblywithanenrichment of4.95weightpercentU-235wouldbeconservatively lesseffthan0.95.Theboronconcentration inthespentfuelpoolisrequiredbyT/S3.9.15tobegreaterthan2400ppmbymeasurement whenfuelassemblies withenrichment greaterthan3.95weightpercentU-235andwithburnuplessthan5,550MWD/MTUareinthefuelstoragepool.

1r4lgP Attachment 2toAEP:NRC:1071N Page3Thermal-H draulicConsiderations TheCookNuclearPlantUpdatedFSARdiscusses analysesperformed todemonstrate theadequacyofthespentfuelpoolcoolingsystemtoremovedecayheat,andalsoan,assessment ofthetimeitwouldtaketoreachbulkboilingintheeventallspentfuelpoolcoolingislost.Themostrecentanalysisofthistypewasperformed byANFinsupportofusingassemblies capableof50,000MWD/MTUexposure.

Theanalysesweredocumented inANFReportNo.ANF-88-09.

Thisanalysiswassubmitted inourletterAEP:NRC:1071 datedAugust19,1988,andsupported theAmendments 118(Unit3.)and104(Unit2)T/Sschanges.'The analysesweremodifiedslightlyasdocumented inRev.1toANF-88-09 tocorrectanerrorindetermining thepoolheatload.Therevisionresultedinachangeinthetimetoreachbulkboilingfrom8.6hoursto5.5hours.)TheUnit2Vantage5assemblies areintendedforuseuptoanaveragedischarge burnupofonly48,000MWD/MTU.Also,theUnit2powerlevelremainsthesameat3411MWt.Therefore, spentfuelpoolcoolinganalysesdocumented inANF-88-09, Rev.1,willboundtheVantage5assemblies andnonewanalysesarebeingsubmitted.

10CFR50.92SinificantHazardsConsideration AnalsisPer10CFR50.92,aproposedamendment toanoperating licensevillnotinvolveasignificant hazardsconsideration iftheproposedamendment satisfies thefollowing threecriteria:

Doesnotinvolveasignificant increaseintheprobability orconsequences ofanaccidentpreviously

analyzed, 2)Doesnotcreatethepossibility ofanewordifferent kindofaccidentfromanyaccidentpreviously analyzedorevaluated, orDoesnotinvolveasignificant reduction inamarginofsafety.Criterion 1Westinghouse hasperformed analysesthatdemonstrate theacceptability oftheproposedchangeswithregardtocriticality.

Theanalysesdemonstrate thatfuelstoredinthespentfuelpoolwillremainsubcritical underdesignbasisconditions.

However,accidents orincidents cantakeplacewhichwouldincreasereactivity suchasdroppingafuelassemblybetweentherackandpoolwallorinadvertently placingafuelassemblyinthewronglocation.

Forthoseconditions, thedoublecontingency principle ofANSIN16.1-1975 canbeapplied.Thatprinciple statesthatoneis'notrequiredtoassumetwounlikely, independent, concurrent eventstoensureprotection againstcriticality.

Thus,thepresenceof A

Attachment 2toAEP:NRC:1071N Page4greaterthanorequalto2400ppmofsolubleboroninthespentfuelpoolcanbeassumedasarealistic initialcondition, sincenotassumingitwouldbeasecondunlikelyevent.Thereactivity ofthefuelstoredinthespentfuelpoolwouldbedecreased byabout0.25delta-k,withapproximately 2000ppmofboron;thatis,foranaccidentoranincidentresulting inanincreaseinreactivity, keffwouldremainlessthanorequalto0.95duetotheeffectofthedissolved boron.Inaddition, paragraph 2.3oftheSERrelatedtoAmendments 118and104forCookNuclearPlantUnits1and2,respectively, statesthat"thereactivity reduction duetotherequiredpoolborationof2400ppmofboronmorethanoffsetsthepotential reactivity'ncreases frompostulated fuelmishandling accidents."

Itisconcluded thattheproposedT/Sschangesshouldnotinvolveasignificant increaseintheprobability orconsequences ofapreviously analyzedaccident.

Criterion 2TheWestinghouse analysesdemonstrate continued acceptability ofthespentfuelpoolregarding criticality.

TheT/Sschangeswillnotresultinphysicalchangestotheplant(otherthantothefuelassemblies, whichwerethesubjectoftheWestinghouse analyses).

Therefore, webelievetheproposedT/Sschangeswillnotcreatethepossibility ofanewordifferent kindofaccidentfromanypreviously evaluated.

Criterion 3Westinghouse hasperformed analysesthatdemonstrate theacceptability oftheproposedchangeswithregardtocriticality.

Theanalysesdemonstrate thatthefuelstoredinthespentfuelpoolwillremainsubcritical underdesignbasisconditions.

However,accidents orincidents cantakeplacewhichwouldincreasereactivity suchasdroppingafuelassemblybetweentherackandpoolwallorinadvertently placingafuelassemblyinthewronglocation.

Forthoseconditions, thedoublecontingency principle ofANSIN16.1-1975 canbeapplied,Thatprinciple statesthatoneisnotrequiredtoassumetwounlikely, independent, concurrent eventstoensureprotection againstcriticality.

Thus,thepresenceofgreaterthanorequalto2400ppmofsolubleboroninthespentfuelpoolcanbeassumedasarealistic initialcondition, sincenotassumingitwouldbeasecondunlikelyevent.Thereactivity ofthefuelstoredinthespentfuelpoolwouldbedecreased byabout0.25delta-k,withapproximately 2000ppmofboron;thatis,foranaccidentoranincidentresulting inanincreaseinreactivity, keffwouldremainlessthanorequalto0.95duetotheeffectofthedissolved boron.Inaddition, paragraph 2.3oftheSERrelatedtoAmendment 118and104forCookNuclearPlantUnits1and2,respectively, statesthat"thereactivity reduction duetotherequiredpoolborationof2400ppmofboronmorethanoffsetsthe e'~0 Attachment 2toAEP:NRC:1071N Page5potential reactivity increases frompostulated fuelmishandling accidents."

Itisconcluded thattheproposedT/Sschangesshouldnotinvolveasignificant reduction inamarginofsafety.Lastly,wenotethattheCommission hasprovidedguidanceconcerning thedetermination ofsignificant hazardsbyproviding certainexamples(48FR14870)ofamendments considered notlikelytoinvolvesignificant hazardsconsideration.

Thesixthoftheseexamplesreferstochangeswhichmayresultinsomeincreaseintheprobability ofoccurrence orintheconsequences ofapreviously analyzedaccident, buttheresultsofwhicharewithinlimitsestablished asacceptable.

TheWestinghouse analysesdemonstrate acceptable resultsfromacriticality perspective usingtheacceptance criteriaoftheNRCStandardReviewPlan.Therefore, webelievetheexamplecitedisapplicable andthattheproposedT/Sschangesdonotinvolveasignificant hazardsconsideration asdefinedin10CFR50.92.

l ATTACHMENT 3TOAEP:NRC:1071N

PROPOSED, REVISEDTECHNICAL SPECIFICATIONS PAGESFORDONALDC.COOKNUCLEARPLANTUNITS1AND2 C

DESIGNFEATURESInaccordance withthecoderequirements specified inSection4.1.6ofFSAR,withallowance fornormaldegradation pursuanttotheapplicable Surveillance Requirements, b.Forapressureof2485psig,andc.Foratemperature of650F,exceptforthepressurizer whichis680F.VOLUME5.4.2Thetotalcontained volumeofthereactorcoolantsystemis12,612+100cubicfeetatanominalTof70F.avg5.5EMERGENCY CORECOOLINGSYSTEMS5.5.1Theemergency corecoolingsystemsaredesignedandshallbemain-tainedinaccordance withtheoriginaldesignprovisions contained inSection6.2oftheFSARwithallowance fornormaldegradation pursuanttotheapplicable Surveillance Requirements.

5.6FUELSTORAGECRITICALITY

-SPENTFUEL5.6.1.1Thespentfuelstorageracksaredesignedandshallbemaintained with:a.Akfequivalent tolessthan0.95whenfloodedwithunborated effwater,b.Anominal10.5inchcenter-to-center distancebetweenfuelassemblies placedinthestorageracks.1.Aseparateregionwithinthespentfuelstorageracks(definedasRegion1)shallbeestablished forstorageofWestinghouse fueltypesofenrichments greaterthan3.95weightpercentU-235andburnuplessthan5,550MWD/MTUinacheckerboard patternconfiguration alternating Category1andCategory2fuelasshowninFigure5.6-1.Westinghouse Category1andCategory2fueldefinitions aregiveninFigure5.6-2.COOKNUCLEARPLANT-UNIT15-5AMENDMENT NO.

DESIGNFEATUREScont'd5.6FUELSTORAGECRITICALITY

-SPENTFUELcont'd2.Aseparateregionwithinthespentfuelstorageracks,definedasRegion2,shallbeestablished forstorageofWestinghouse fuelofanenrichment lessthanorequalto3.95weightpercentU-235oranenrichment greaterthan3.95weightpercentU-235butwithaburnupgreaterthanorequalto5,550MWD/MTU,andExxon/ANF fuelofanenrichment lessthanorequalto4.23weightpercentU-235fora17x17assemblyorlessthanorequalto3.50~eightpercentU-235fora15x15assembly.

3.TheboundarybetweentheRegions1and2mentioned aboveshallbesuchthatthecheckerboard patternstoragerequirement ofRegion1shallbecarriedintoRegion2byatleastonerowasshowninFigure5.6-1.5.6.1.2Fuelstoredinthespentfuelstorageracksshallhaveamaximumnominalfuelassemblyenrichment asfollows:DescritionMaximumNominalFuelAssemblyEnrichment Wt.I2351)Westinghouse 15x15STD15x15OFA4.952)Exxon/ANF 15x153.503)Westinghouse 17x17STD17x17OFA17x17V54.954)Exxon/ANF 17x174.23CRITICALITY-NEW FUEL5.6.2.1Thenewfuelpitstorageracksaredesignedandshallbemaintained withanominal21inchcenter-to-center distancebetweennewfuelassemblies suchthatKffwillnotexceed0.98whenfuel,assemblies areplacedintheeffpitandaqueousfoammoderation isassumed.COOKNUCLEARPLANT-UNIT15-6AMENDMENT NO.

~~ctqeS DESIGNFEATUREScont'd5.6.2.2Fuelstoredinthenewfuelstorageracksshallhaveamaximumnominalfuelassemblyenrichment asfollows:DescritionMaximumNominalFuelAssemblyEnrichment Wt.s2351)Westinghouse 15x15STD15x15OFA4.552)Exxon/ANF 15x153.503)Westinghouse 17x17STD17x17OFA17x17V54.554)Exxon/ANF 17x174.23DRAINAGE5.6.3Thespentfuelstoragepoolisdesignedandshallbemaintained topreventinadvertent drainingofthepoolbelowelevation 629'".CAPACITY5.6.4Thefuelstoragepoolisdesignedandshallbemaintained withastoragecapacitylimitedtonomorethan2050fuelassemblies.

5.7SEISMICCLASSIFICATION 5.7.1Thosestructures, systemsandcomponents identified asCategoryIitemsintheFSARshallbedesignedandmaintained totheoriginaldesignprovisions contained intheFSARwithallowance fornormaldegradation pursuanttotheapplicant Surveillance Requirements.

5.8METEOROLOGICAL TOWERLOCATION5.8.1Themeteorological towershallbelocatedasshowninFigure5.1.1.5.9COMPONENT CYCLICORTRANSIENT LIMIT5.9.1Thecomponents identified inTable5.9-1aredesignedandshallbemaintained withinthecyclicortransient limitsofTable5.9-1.COOKNUCLEARPLANT-UNIT15-7AMENDMENT NO.

~~0'll'tjl'i-14)I4 IIIIIiI,Region1to2BoundarylReonlRegion2REGZON1,CATEGORY2FUELREGZON1,CATEGORY1FUELREGZON2FUELFIGURE5.6-lDONALDC.COOKNUCLEARPLANTSCHEMATIC FORSFPINTERFACE BOUNDARYBETWEENREGIONSIAND2COOKNUCLEARPLANT-UNIT15-8AMENDMENT NO.

+14l-IRegion1StorageRequirements Burnupvs.1nitialEnrichment IFuelAssemblyBurnup(GWD/MTU) 32-,(4.95~30.45)28-24-ACCEPTABLE FORSTORAGEASCATEGORY1FUEL20-16-12-(3.95,5.55)(4.95,5.55)REQUIREDTOBESTOREDASCATEGORY2FUEL02.2(2.3,0.0)2.6.3.43.8.4.24.6InitialWestinghouse FuelEnrichment w/oCategory1-Regionaboveandincluding linethrough2.3w/oCategory2-RegioninlowerrightboxFIGURE5.6-2DONALDC.COOKNUCLEARPLANTSFPREGION1BURNEDFUELASSEMBLYMINIMUM.BURNUP VS.INITIALU-235ENRICHMENT CURVECOOKNUCLEARPLANT-UNIT15-9AMENDMENT No.

~e TABLE5.9-1COMPONENT ReactorCoolantSystemCOMPONENT CYCLICORTRANSIENT LIMITSCYCLICORTRANSIENT LIMIT200heatupcyclesatlessthanorequalto100F/hrand200cooldowncyclesatlessthanorequalto100F/hr(pressurizer cooldownat00lessthanorequalto200F/hr).DESIGNCYCLEORTRANSIENT Heatupcycle-TfromlessthanorequaltoBOFto0greaterthanorequalto547F.Cooldowncycle-Tfromave0greaterthanorequarto547F0tolessthanorequalto200F.80lossofloadcycles.Withoutimmediate turbineorreactortrip.40cyclesoflossofoffsiteA.C.electrical power.LossofoffsiteA.C.electrical powersourcesupplying theonsiteClasslEdistribution system.80cyclesoflossofflowinonereactorcoolantloop.Lossofonlyonereactorcoolantpump.400reactortripcycles.100%to0%ofRATEDTHERMALPOWER.200largestepdecreases inload.100%to5%ofRATEDTHERMALPOWERwithsteamdump.COOKNUCLEARPLANT-UNIT15-10AMENDMENT NO.

TABLE5.9-1COMPONENT COMPONENT CYCLICORTRANSIENT LIMITSCYCLICORTRANSIENT LIMITDESIGNCYCLEORTRANSIENT ReactorCoolantSystem1mainreactorcoolantpipebreak.Breakinareactorcoolantpipegreaterthan6inchesequivalent diameter.

Operating BasisEarthquakes 400cycles-20earthquakes of20cycleseach.Secondary System50leaktests.5hydrostatic pressuretests1steamlinebreakPressurized to2500psiaPressurized to3107psig.Breakinasteam,linegreaterthan5.5inchesequivalent diameter.

5hydrostatic pressuretestsPressurized to1356psig.COOKNUCLEARPLANT-UNIT15-11AMENDMENT NO.

'\VCl VOLUME5.4.2Thetotalwaterandsteamvolumeofthereactorcoolantsystemis012,612+100cubicfeetasanominalTavgof70F.5.5METEOROLOGICAL TOWERLOCATION5.5.1Themeteorological towershallbelocatedasshownonFigure5.1-1.5.6FUELSTORAGECRITICALITY

-SPENTFUEL5.6.1.1Thespentfuelstorageracksaredesignedandshallbemaintained with:a.AKequivalent tolessthan0.95whenfloodedwithunborated effwater,b.Anominal10.5-inch center-to-center distancebetweenfuelassemblies, placedinthestorageracks.1.Aseparateregionwithinthespentfuelstorageracks(definedasRegion1)shallbeestablished forstorageofWestinghouse fueltypesofenrichment greaterthan3.95weightpercentU-235andburnuplessthan5,550MWD/MTUinacheckerboard patternconfiguration alternating Category1fuelandCategory2fuelasshowninFigure5.6-1.Westinghouse Category1andCategory2fueldefinitions aregiveninFigure5.6-2.2.Aseparateregionwithinthespentfuelstorageracks,definedasRegi'on2,shallbeestablished forstorageofWestinghouse fuelofanenrichment lessthanorequalto3.95weightpercentU-235oranenrichment greaterthan3.95weightpercentU-235butwithaburnupgreaterthanorequalto5,550MWD/MTU,andExxon/ANF fuelofanenrichment lessthanorequalto4.23weightpercentU-235fora17x17assemblyorlessthanorequalto3.50weightpercentU-235fora15x15assembly.

3.TheboundarybetweentheRegions1and2mentioned aboveshallbesuchthatthecheckerboard patternstoragerequirement ofRegion1shallbecarriedintoRegion2byatleastonerowasshowninFigure5.6-1.COOKNUCLEARPLANT-UNIT25-5AMENDMENT NO.

5.6FUELSTORAGECRITICALITY

-SPENTFUELcont'd5.6.1.2Fuelstoredinthespentfuelstorageracksshallhaveamaximumnominalfuelassemblyenrichment asfollows:DescritionMaximumNominalFuelAssemblyEnrichment Wt.82351)Westinghouse 15x15STD15x15OFA4.952).Exxon/ANF 15x15-,.3.503)Westinghouse 17x17STD17x17OFA17x17V54.954)Exxon/ANF 17x174.23CRITICALITY

-NEWFUEL5.6.2.1Thenewfuelpitstorageracksaredesignedandshallbemaintained withanominal21inchcenter-to-center distancebetweennewfuelassemblies suchthatK-'fwillnotexceed0.98whenfuelassemblies areplacedineffthepitandaqueousfoammoderation isassumed.5.6.2.2Fuelstoredinthenewfuelstorageracksshallhaveamaximumnominalfuelassemblyenrichment asfollows:DescritionMaximumNominalFuelAssemblyEnrichment Wt.%2351)Westinghouse 15x15STD15x15OFA4.952)Exxon/ANF 15x153.503)Westinghouse 17x17STD17x17OFA17x17V54.954)Exxon/ANF 17x174.23COOKNUCLEARPLANT-UNIT25-6AMENDMENT NO.

1~

DRAINAGE5.6.3Thespentfuelstoragepoolisdesignedandshallbemaintained topreventinadvertent drainingofthepoolbelowelevation 629'4".CAPACITY5.6.4Thespentfuelstoragepoolisdesignedandshallbemaintained withastoragecapacitylimitedtonomorethan2050fuelassemblies.

5.7COMPONENT CYCLICORTRANSIENT LIMIT5.7.1Thecomponents identified inTable5.7-1aredesignedandshallbemaintained withinthecyclicortransient limitsofTable5.7-1.COOKNUCLEARPLANT-UNIT25-7AMENDMENT NO.

/4gfr,4I lItll~gfon1to?BoQAd~IRefon2REGION1,CATEGORY2FUELREGION1,CATEGORY1FUELREGION2"UELFIGURE5.6-1DONALDC.COOKNUCLEARPLANTSCHEMATIC FORSFPINTERFACE BOUNDARYBETWEENREGIONS1AND2COOKNUCLEARPLANT-UNIT25-8AMENDMENT NO.

CI Region1StorageRequirements Burnupvs.InitialEnrichment FuelAssemblyBurnup(GWD/MTU) 32--.(4.95~30.45)28-24-ACCEPTABLE FORSTORAGEASCATEGORY1FUEL20-16-12-(3.95~5.55)(4.95,5.55)02.2(2.30.0)2.63.4REQUIREDTOBE"STOREDASCATEGORY2'UEL'.84.24.6InitialWestinghouseFuelEnrichmen tw/olICategory1-Regionaboveandincluding linethrough2.3w/oiCategory2-RegioninlowerrightboxIFIGURE5.6-2DONALDC.COOKNUCLEARPLANTSFPREGION1BURNEDFUELASSEMBLYMINIMUMBURNUPVS.INITIALU-235ENRICHMENT CURVECOOKNUCLEARPLANT-UNIT25-9AMENDMENT NO.

TABLE5.7-1COMPONENT CYCLICORTRANSIENT LIMITSCOMPONENT CYCLICORTRANSIENT LIMITDESIGNCYCLEORTRANSIENT ReactorCoolantSystem200heatupcyclesatlessthanorequalto100F/hrand200cooldowncyclesatlessthanorequalto100F/hr(pressurizer cooldownat00lessthanorequalto200F/hr).Heatupcycle-Tfromlessthanorequalto550Fto0greaterthanorequalto547F.Cooldowncycle-Tfromave0greaterthanorequalto547F0tolessthanorequalto200F.80lossofloadcycles.Withoutimmediate turbineorreactortrip.40cyclesoflossofoffsiteA.C.electrical power.LossofoffsiteA.C.electrical powersourcesupplying theonsiteClass1Edistribution system.80cyclesoflossofflowinonereactorcoolantloop.Lossofonlyonereactorcoolantpump400reactortripcycles.100%to0%ofRATEDTHERMALPOWER.200largestepdecreases inload.100%to5%ofRATEDTHERMALPOWERwithsteamdump.COOKNUCLEARPLANT-UNIT25-10AMENDMENT NO.

TABLE5.7-1Continued COMPONENT CYCLICORTRANSIENT LIMITSCOMPONENT ReactorCoolantSystemCYCLICORTRANSIENT LIMIT1mainreactorcoolantpipebreak.DESIGNCYCLEORTRANSIENT Breakinareactorcoolantpipegreaterthan6inchesequivalent diameter.

Operating BasisEarthquakes 400cycles-20earthquakes of20cycleseach.Secondary System50leaktests.5hydrostatic pressuretests1steamlinebreakPressurized to2500psia.Pressurized to3107psig.Breakinasteamlinegreaterthan5.5inchesequivalent diameter.

5hydrostatic pressuretestsPressurized to1356psig.COOKNUCLEARPLANT-UNIT25-11AMENDMENT NO.

I