ML17254A680

From kanterella
Revision as of 14:03, 29 June 2018 by StriderTol (talk | contribs) (Created page by program invented by StriderTol)
Jump to navigation Jump to search
Demonstration of Conformance of Exxon Nuclear Co Fuel to Westinghouse K(Z) Operating Envelope for Re Ginna Nuclear Power Plant.
ML17254A680
Person / Time
Site: Ginna Constellation icon.png
Issue date: 09/30/1985
From:
WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:
Shared Package
ML17254A679 List:
References
NUDOCS 8512200249
Download: ML17254A680 (13)


Text

DEMONSTRATION OFTHECONFORMANCE OFEXXONNUCLEARCOMPANYFUELTOTHEWESTINGHOUSE K(Z)OPERATING ENVELOPEFORTHEROBERTE.GINNANUCLEARPOWERPLANTWestinghouse ElectricCorporation NuclearTechnology DivisionNuclearSafetyDepartment Safeguards Engineering andDevelopment September 19858512200249 851216PDRADOCK05000244',P'DR I.ntroduction Thisdocumentreportstheresultsofasensitivity studythatwasperformed inordertodemonstrate conformance ofExxonNuclearCompanynuclearfuelintheRobertE.GinnanuclearpowerplanttotheWestinghouse K(z)operating envelope.

Inparticular, theresultsof.thisanalysisshowthatforskewedtothetoppowershapes,inadditiontothepowershapepeakedatthemid-coreelevation, thattheworstpeakcladdingtemperature (PCT)intheunlikelyeventofaLoss-Of-Coolant-Accident (LOCA)remainsbelowthe2200deg-Flimitasspecified byAppendixKof10CFR50.46.

II.MethodofAnalsisThesensitivity studywasperformed usingtheLOCTAcomputercodeoftheWestinghouse 1981LargeBreakLOCAEvaluation Model(WEM)tocalculate thePCTforExxonfuelforthreepowershapes.Thepower.shapesinvestigated Iwerepeakedat6.0ft.,8.0ft.,andat10.5ft.ThepowershapesusedintheLOCAanalysesareshowninFigures1-3.ThepeakpowerofeachpowershapeislimitedbythecurrentK(z)envelopefortheRobertE.Ginna(RGE)powerplant.ThecurrentK(z)envelopeforRGEassumesamaximumtotalpeakingfactorof2.32,andahotchannelenthalpyrisefactorof1.66.

Thefueldesignparameters fortheExxonfuelwereobtainedfromtheExxonNuclearCompanythroughathree-party proprietary agreement betweenWestinghouse, Rochester Gas6Electric, an'dExxon.Thefuelparameters specifictoeachpowershapeweregenerated byExxonandtransmitted toWestinghouse.

Thefuelparameters, whichincludedfuelpellettemperatures andgappressures, werethenusedasinputineachoftheLOCTAcalculations.

TheresultsoftheLOCTAcalculations aresummarized inthefollowing table:'IComarisonofExxonFuelPeakCladdinTemeraturesPowerShapePeakPCTOFPCTElevation PCTTimesec.6~08'10'1781159815287.257'510.001065..14'Theseresultsdemonstrate thatfortheRobertE.GinnaUnit,thatthechoppedcosinepowershape(i.e.6.0ft.peakedshape)generates themostlimitingpeakcladtemperature.

Figures4-6showthecladtemperature responseforthepeaknodeforthe6.0,8.0,and10.5ft.powershapesrespectively.

Animportant observation oftheseresultsisthatforthetop-skewed shapes,thepeakcladdingtemperature occursduringtheblowdownphase.Thisisimportant becausemostoftheAppendixKprescribed analytical modelshavetheirgreatestinfluence duringtherefloodphase.Apeak

'~cladtemperature whichoccursduringrefloodissensitive tocore-wide andsystem-wide hydraulic phenomena, whileablowdownpeakisastrongerfunctionofinitialfuelstoredenergy.Acomparison ofthepeakcladtemperatures duringtheblowdownandrefloodphasesforeachofthesepowershapesprovidesamoreconclusive demonstration thatthechoppedcosinepowershapeproducesthemostlimitingLOCAresults.ComarisonofPeakCladdinTemeraturesDurinBlowdownPowerShapePeakPCT-Blowdown opPCTElevation Timesec.6.08'10'1635159815286~007'510.005'5'4'Thecomparison ofpeakcladtemperatures duringblowdownshowsthatthehighestPCToccursforthechoppedcosinepowershape.Thisisreasonable.,

because6.0ft.shapepermitsthehighesttotallocalpeakingfactor(2.32).ThefactthatthePCTforthetop-skewed shapesoccursbelowthepeakpowerlocationisduetothebetterheattransferathigherelevations thatoccursduringtheperiodofnegativecoreflow.

ComarisonofPeakCladdinTemeraturesDurinRefloodPowerShapePeakPCT-Reflood OFPCTElevation Timesec.6~08~010'1781158514587'5F0010.001067468Thecomparison ofrefloodpeakcladtemperatures showsanevenwidermarginbetweenthechoppedcosineshapeandthetop-skewed powershapes.Znadditiontoshowingthatthechoppedcosinepowershape,isthe"worst"powershapeforaLOCAanalysisofRGEwithExxonfuel,italsodemonstrates alargemargintothe2200deg-Flimitforthetop-skewed shapesforthisplant.III.UseofNon-Exxon FuelHdraulicsThissensitivity studywasperformed byre-calculating thecladVItemperature responseforExxonforthethreepowershapesusingtheLOCTAcomputercode.Thehotassemblyhydraulics wasnotre-calculated fortheExxonfuel.Theblowdownandrefloodhydraulic transients aregenerated usingtheSATAN,WREFLOODandCOCOcomputercodes.Existingblowdownandrefloodhydraulics fromapreviousRGEplantspecificanalysiswithW-OFAfuelwereusedashotassemblyboundaryconditions fortheLOCTAcalculations.

UseoftheOFAhydraulics arejustifiable forthissensitivity studyonthefollowing basis:

(l)TheW-OFArodsizeissmallerthantheExxonrodsize.ThiswillresultinaslowerrefloodofafullcoreofW-OFAfuel.Thus,foragivenpowershape,theuseoftheOFAcorerefloodrateprovidesaconservative'eflood ratefortheExxonfuelheat-upcalculation.

(2)Previoussensitivities withtop-skewed powershapesinSATANhavehotshownalargeeffectontheend-of-blowdown fueltemperatures.

Thus,theuseofSATANchoppedcosinepowershaperesultsfortop-skewed LOCTAcalculations canbeconsidered sufficiently accurateforaroughsensitivity study.Becauseofthewidemarginbetweenthecosineandthetop-skewed shapePCTsinthisanalysis, re-calculation oftheSATANtransient isnotexpectedtochangetheconclusions ofthisanalysis.

IV.Conclusions TheWestinghouse LargeBreakLOCAEvaluation Modelcladheat-upcomputercode,LOCTA,wasusedtoanalyzeExxonfuelforthreepowershapes.Theresultsconfirmed thatthepowershapepeaked..at thecenterofthecoreproducesthehighestpeakcladdingtemperature.

ThisresultfortheExxonfuelisconsistent withpowershapestudiesperformed byWestinghouse withthesamecomputercodesforWestinghouse fuel.Theresultsofthisstudydemonstrate thattheExxonfuelintheRobertE.Ginnanuclearpowerplantconformstothecurrentoperating K(z)envelopefortop-skewed powershapes.Whiletheentiretransient wasnotrecalculated forthisanalysis, acompletere-analysis wouldnotbeexpectedtochangetheconclusions ofthissensitivity study.\

0.03.04.25,.4.75 5.255.75-6.25 6.757.257.759.012.1.S4.04.55.05.56.06.57.07.58.010.5COREHEIGHT(FEET)Figure1.AxialPowerShapePeakedat6.0ft.(ChoppedCosinePowerShape) 0.01.02.03.04.05.06.07.08.09.010.011.012.0

.51.52.53.54.55.56.57.58.59.510.511.5COREHEIGHT(FEET)Figure2.AxialPowerShapePeakedat8.0ft; 2.S2.0M~1.SC51.0.5.0.01.02.03.04.05.06.07.08.09.010.011.012.0

.51.52.53.54.55.56.57.58.59.510.511.5COREHEIGHT(FEET)Figure3.AxialPowerShapePeakedat10.5ft.

c~tlctl~clvbttt~ovtv[5tovlt5vttl51u0tO.~Cl(IC.C0tlte~OvltSvttlll~0~vC1[vt<<01~00IutlfiC00t'llItlJt~tot5tll~ItW>.OCC5'AO.Ovoltd.O50vAOS<lvl~55C>Figure4.CladTemperature ResponseforPCTLocationforthe6.0ft.PowerShape.

~Oll~lC~CllilCt~00lulltOOC~SwltlS'IUOt0'OCClCO,O~CaatOol~SsstlCCAOArt.lllit.wOS 000~VOS'i~tCSlitl~CitySy$0tll+lVlC000.0C\SSOO.ONXol000.00.088SINSISCCIFigure5.-CladTemperature ResponseforPCTLocationfor8.0ft.PowerShape

~OltV<C,CIVVVt<<OV<Vt<VOVtV5Vatt5<VDV0,~Ott<C10.5VtvvVOvtV5vVVtC<JDAVC.1t<<V,<<0<

VODOvv51~0.00<1<<Vtvv~O,DOA<~<W~0000.0o1500.0XE<Co1000.0lr0.0CII<t<5CCISg8Figure6.CladTemperature ResponseforPCTLocationforthe10.5ft.PowerShape-11