ML17037C516

Nine Mile Point Nuclear Station, Unit 1 - Letter Submitting Analyses Which Determine Effects of Fuel Densification and Appropriate Changes to Technical Specifications for Fuel to Be Inserted During Spring 1974 Refueling

ML17037C516
Person / Time
Site:	Nine Mile Point
Issue date:	01/22/1974
From:	Raymond P D Niagara Mohawk Power Corp
To:	Ziemann D L US Atomic Energy Commission (AEC)
References
Download: ML17037C516 (32)

Text

AECDXSUTIONFORPART50DOCKETMATER(TEMPORARY FORM)CONTROLNO:FILE:8FROAA1:NiagaraMohawkPowerCorpSyracuse, N;Y.13202P.D.RaymondDATEOFDOC1-22-74DATEREC'D1-23-74LTRMEMORPTOTHERTO:D.L.ZiemannORIG3signedqCCOTHERSENTAECPDRxSENTLOCALPDRXCLASSUNCLASSXXXXPROPINFOINPUTXXXXNOCSREC'D40DOCKETNO:50-220DESCRIPTION:

Ltrnotarized 1-22-74,transthefollowing:

PLANTNAME:NineMilePointUnit$P1ENCLOSURES:

ProosedChanetoTechnical Secifications:

Densification AnalysesandRelatedTechnical Specifications ChangesforType5andTypeDONOTREMOVEACKNOWLEDGED (3Orig637cysrec'd)FORACTION/INFORMATION 1-23-74GCBUTLER(L)W/CopiesCLARK(L)W/CopiesGOLLER(L)

W/CopiesKNIEL(L)W/CopiesSCHWENCER(L)

W/CopiesSTOLZ(L)W/CopiesVASSALLO(L)

'W/CopiesSCHEMEL(L)

W/Copis~ZIEMANN(L)W/9CopiesDICKER(E)

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W/CopiesINTERNALDISTRIBUTION REGAN(E)W/CopiesW/CopiesW/CopiesW/CopiesAECPDR+GCFRSMP-506A~NTZING/STAFF CASEGIAMBUSSO BOYDMOORE(L)(BWR)DEYOUNG(L)(FllR)O'SKOVHOLT (L)P,COLLINSFILE&REGION(d))

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t,h'egUlatory DocketFileNIAGARAMOHAWKPOWERCORPORATION NIAGARA~MOHAWK300ERIEBOULEVARD, WESTSYRACUSE.

N.Y.13202January22,1974Mr.DennisL.Ziemann,ChiefOperating ReactorsBranch82Directorate ofLicensingUnitedStatesAtomicEnergyCommission Washington, D.C.20545

DearMr.Ziemann:

JAN23)974~

'L'InA)EIIpn~It-iiVu~~

Re:NineMilePointUnit1AECDocketNo.50-220NiagaraMohawkPowerCorporation hascommitted initsletterofOctober15,1973tosupplyanalysestodetermine theeffectsoffueldensi-ficationn andtheappropriate changestoTechnical Specifications forthefueltobeinsertedduringtheSpring1974refueling.

Theanalyseshavebeenperformed usingthe,guidanceprovidedintheenclosure toyourDecember5,1973letter,"Modified GEModelf'rFuelDensification".

TheseanalysesandtheproposedTechni:cal Specification changesareattachedherewith.

Itisanticipatedthatthesechangeswillnotlimitplantpowerlevelbelowitsfulldesignratingof1850megawatts forpowerdistributions expectedduringnormaloperation.

TheSiteOperations ReviewCommjttee andtheSafetyReviewand.AuditBoardconcurwiththeseproposedTelchnical Specification changes.Verytrulyyours,Viceesident-Engineering

/sqAttachment Subscribed andsworntobeforemethis~~ayofJanuary,1974.VALERIEhl.KELLYNoteryPobhcinthe'teteofNewYorkQoeliiled InOnon.Eo..No.3Cn50C729~MyCorernlrrlon fnplret"Merch30rl9rIrr'~,JANP3)ygI EENCE'Uqp lrQQ,~fyICII)CEERX rI

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Regulatory DocketFileSpecification ChangesForgoaeraa~e.

nnaiadType5andType6FuelI.AnalsesofFuelDensification EffectsThissectionpresentsresultsoftheeffectsofdensification inthe8x8reloadfuelasdetermined fromapplication ofthemodelsdescribed inJRefer'ence1.A.LocalPowerSpikinA'nanalysi's ofpotential localpower.spikesduetoaxialgapsinafuelpelletcolumnforGeneralElectricBMR'semployinq anRx8fuellatticedesignhasbeenperformed.

Thisanalysisemploysthesamemethodandbasicassumotions thatwerereportedinReference l.Important asnects.'fthisanalysisarenotedasfo11ows:l.The,equationemployedtocalculate maximumqapsizeisthatnotedinReference 1:dL=~965-+0.0025)L2wheredL=maximumaxialqaolengthL=fuelcolumnlengthPi=meanvalueofmeasuredinitialplletdensity(immersion

-.5X)0.0025=allowance forirradiation inducedcladdinggrowthandaxialstraincausedbyfuel-clad mechanical interacti on.2.Themagnitude ofthepowerspikeversusgapsizeforfuelrodsofthe8x8desiqnisshowninFigure1fornormaloperating conditionsandFigure2forcoldzerovoidconditions.

~4 3.Thecorepowerhistogram employedv>>asfora13.4kl</ftCmaximumdesignlinearheatgeneration rate:.seeFigure3.TheresultsfromthisanalysisareshowninFiaure4withinitialfueldensityasaparameter.

Thelineshownforaninitialfueldensityof95%T.D.isconsidered tobemostrepresentative considering currntGeneralElectricdataonmanufactured fuelpelletdensities.

ThepowersnikepenaltyshowninFigure4forseveralmeanpelletdensities asafunctionofaxialposition, istherequiredmarginwhichmustbemaintained durinqnormalooeration betweentheactualpeakoperating condition andtheoeakdesignLHGR;i.e.,13.4kM/ft,Maintaining thismarginwillassure,withbetterthan95%confidence, thatnomorethanonerodwillexceedthedesiqnneakLHGRduetotherandomoccurrence ofpowerspikes-resulting fromaxialfuelcolumngans.Consistent withGeneralElectric's positionondensification previously discussed inReference 2anditssupplements, theresultsofthisanalysisareconsidered toheaveryconservative representation ofthepoweroeakinqpenaltyrequiredtoaccommodate 4potential axialfuelcolumngapsduringnormaloperating conditions inGeneralElectricBHR's.Sincetheresultsofthepowerspikinqanalysisfornormaloneration willbeutilizedtolimitbundlepowertoassurethattherandomoccurrence ofpowerspikeswillnotresultinexceeding thedesignpeakLHGR,itisnotbelievednecessary toseparately considerpowersnikesintheanalysisoftransients oraccidents whichhaveasaninitialcondition someformofnormaloneration.

Thecontrolroddropaccidentisuniqueintherespectthatitbeginsatthecoldcondition,andisnotaffectedbynormaloperating powerlevel.Further,theexistence offuelcolumngapscanresultinoowerspikinginthecoldcondition duringacontrolroddropwhichshouldthusbeconsidered intheevaluation ofthisaccident.

Forthispurpose,aseparatepowerspikinqanalysishasbeenperformed usingthesameassumptions asindicated above,butemployina apowerspikeversusgapsizecalculated tooccurinthecoldconditionwithzerovoWs(Figure2).Thisanalysiswasperformed foraconservative maximumgapsizecalculated employing apelletaverageimmersion densityof94.5ÃT.D.,andapositionnearthetopofthecoreinordertomaximizetheoowersnikingeffect.Thisanalysisyieldeda99Kprobabil'ity th'atanyqivenfuelrodwouldhaveapowerspikeof45K.B.CladdingCreepCollapseUsingthesameconservative basespresented inReferences 1and2,thecriticalpressureratio;i.e.,ratioofcollapsepressuretoactualcoolantpressure, wascalculated.

Figure5presentsthecladmid-walltemperature versustimeforthe8x8reloadfuel..Nocreditistakenforinternalqaspressureduetoreleasedfissiongasorvolatiles.Theinternalpressureduetoheliumbackfillat1atmosphere duringfabrication isconsidered.

Thefuelcharacteristics forcreepcollapse'calculations areasfollows:CladO.D.,in.CladThickness, in.0.4930.034+0:003PeakLHGR,kw/ft13.4FastFluxvlNev.n/cm2-sec 4.37x1013Figure6givesthecalculated criticalpressureratio.Asevidenced bythecurve,thecalculated criticaloressureratioisalwayso1.0.C.Increased LinearHeatGeneration RateThefollowing expression wasemployedtocalculate thedecreaseinfuelcolumnlengthduetodensification incalculation ofapenaltyinlinearheatgeneration rate:~0.965-5L=2L 0~I WherehL=decreaseinfuelcolumn.lengthL=fuelcolumnlengthp;=meanvalueofmeasuredinitialpelletdensity(immersion

-.5/}Thelengthreduction duetodensification ascalculated bytheaboveequationrequiresknowledge ofthemeanimmersion density(p;}obtainedfromthegCdata.Acorrection of0-.5AT.D.isappliedtoconverttheimmersion densitytoageometric density.Themeanpelletimmersion densityforNineMilePoint18xSreloadfuelis95.29/.T.D.Thisresultsin:AL=0.965-0.9529-0.005=0.01709=0.009L22orAL=0.9XLDue=-tothermalexpansion, anSxSpelletnormallyexnandsingoinqfromthecoldtohotcondition, anamountequalto1.25forapelletat13.4kW/ft.Thisincreaseinlengthfromthecoldtohotcondition isnottakencreditforineitherdesigncalculations orintheprocessofcorenerformance analysisduringreactoroperations.

Thecoldpelletlengthisassumedfortheseconditions.Therefore, thedecreaseinpelletlengthduetodensification ismorethanoffsetbypelletaxialthermalexpansion.

D.Decreased Pellet-Cl adThermalConductivitFigure7providesplotsofMaximumAveragePlanarLinearHeatGeneration Rate(MAPLHGR) versusexposure, forNineMilePointSx8reloadfuel.Them(omega}curveissuitableforincorporation intotheplanttechnical specifications.

TheLOCAanalyseswereperformed usingtheapprovedInterimAcceotance CriteriaModelwithgapconductance valuesascalculated perthenewGEGAPIIImodelwithAECmodifications.(1

}

REFERENCES l.Hinds,J.A.,(GeneralElectric) lettertoY.A.Hoore(USAEC),"PlantEvaluations withGEGAPIII,"December12,1973.2."GenericDesignInformation forGeneralElectricReloadFuel",NEDO-20103; September 1973.3.NEDtl-10735, Supplement 6,"FuelDensification EffectsonGeneralElectricBoilingMaterReactorFuel,"August1973.

,7.0~FIGURE18x8POWERSPIKEVERSUSGAPSIZE-NORMALOPERATION 6.05.0hPp4.0(I)3.02.01.00RODRELATIONSHIP (gO2OeO2O3O5O~05gonadjacentPellet-npod59~opg~o~ongo<~9@9dyponRod8apinRogreccdg5onRod81EffectofagapinRoEffecofa9dg4onRodNEffectofa9ap01.02,03.0GAPSIZE(CM)4.05.06.0

FIGURE28x8POWERSPIKEVERSUSGAPSIZE-COLDZEROVOIDCONDITION RODRELATIONSHIPS OlO2O4020305o~O4O~0~~0o~d>onRod1inRooggaP~"<~g.ectoRod4onRod1EffectofqapinREffectofgapvariRod5onRod]GAPSIZE(Cg)

FIGURE34.01.21.0.8.6A'.0C).2012LHGR(KH/FT=X)13140

FIGURE48x8POMERSPIKEPENALTYYSAXIALPOSITION-NORMALOPERATION 1.02.03.096,095.04.04.03.094.02.095.096.056-7DISTANCEFROMBOTTOMOFCORE(FEET)81012

690FIGURE5CLADDINGAVERAGETEMPERATURE ATAFUELCOLUMNAXIALGAP6806706606500640UJ63062086'j0a-6005905805705605500IRRADIATION TIME,YEARS

4.0FIGURE6CLADCRITICALCOLLAPSEPRESSURERATIOVERSUSTIME8x8RELOADFUEL3.01.023IRRADIATION TIME,YEARS 0

I716FIGURE7MAPLHGRVERSUSEXPOS'MAXIMUMALLOWABLE TOSTAYBELOWCURRENTTECHNICAL SPECIFICATION LIMITFORLHGR0MAXIMUMALLOWABLE WITHGEGAPIIIANDAEClODIFICATIONS 15~1413~12OC1005,00010,00015,00020,000AVERAGEPLANAREXPOSURE(mWd/t)25,00030,000

II.ProposedChanestoTechnicalSpecificationsChangepages37a,37b,37c,etc.asfollows:~ChaneAAddtheattachedFigure3.1.7etotheTechnical Specification.

UndertheLimitingCondition forOperation 3.1.7,addFigure3.1.7etothelistoffiguresattheendofthelastsentenceinparagraph a.~ChaneBRep'lacethenotes;totheequationinLimitingConditions forOoeration 3.1.7bwiththefollowing:

"LHGRd=DesignLHGR=17.5kw/ftfor7x7fuelor13.4kw/ftfor8x8fuelQp/p)~AX=Maximumpowerspikingpenalty'0.040for7x7fuelor0.027forBx8fuel.LT=TotalCorelenath=12ft.L=Axialpositionabovebottonofcore"~ChaneCAddFigure3.1.7etothelistoffiquresinthethirdoaraaranh oftheBases3.1.7a.ReasonsforChanesA,BRCTheresultsofanalysesperformed for8x8reloadfuelhasindicatedthatlimitsonflAPLHGRandpowersoikingoenalties duetodensification arerequired.

TheselimitsastheyapplytoType5andType6fuelarepresented forincorporation intoNineNilePointUnit1Technical Specifications.

Similarlimitsforpreviously loaded7x7fuelarealreadynartof-the'echnicalSpecifications.

JIE 17NINEhflLEPOINT-PilIT 116~4~14~13~12OC1005,00010,00015,00020,000AVERAGEPLANAREXPOSURE(ml<d/t)25,00030,000FIGURE'.1.7.eftAXIfGAUMALLOWABLE AVERAGEPLANARLHGRAPPLICABLE TOFUELTYPE5and6 00A'l