ML17320A971

Forwards First Round Questions Following Evaluation of Exxon Rept, Steam Tube Rupture Incident at Prairie Island Unit 1, PTSPWR2 Vs Data,Preliminary Benchmark Analysis.

ML17320A971
Person / Time
Site:	Prairie Island, Cook, 05000000
Issue date:	03/06/1984
From:	ABRAMSON P B, WEI T Y ARGONNE NATIONAL LABORATORY
To:	GUTTMANN J Office of Nuclear Reactor Regulation
Shared Package
ML17320A970	List: ML17320A971 ML17320A972 ML17320A973 ML17320A974
References
CON-FIN-A-2311 NUDOCS 8404040304
Download: ML17320A971 (5)

Text

ARCONNENATIONALABORATORY 9700Sour'essAvE~A~0MgIllinois60439Td~~s)12/972-4868March6,1984Mr.JackGuttmannReactorSystemsBranchDivisionofSystemsIntegration OfficeofNuclearReactorRegulation U.S.NuclearRegulatory Commission Washington,.

D.C.20555

Subject:

FINA2311TaskIExxonPTSPWR2ReviewII

DearMr.'Guttmann:

Wehavecompleted thereviewoftheExxonreport,"SteamTubeRutpureIncidentatPrairieIslandUnit1-PTSPWR2versusData,Preliminary Benchmark Analysis" (December 1983),whichExxonsubmitted asthefirstbenchmark caseinitspackageofcodequalification materialfortheChapter15transient analysiscodePTSPWR2.Pleasefindenclosedasetoffirstroundquestions onthereportforExxon.Inaddition, asrequested, wehaveenclosedanothercopyofthefirstroundquestions, sentonSeptember 30,1983,onthePTSPWR2codemodelsasdescribed inthedraftofXN-74-5(P),

Revision2,"Description oftheExxonNuclearPlantTransient Simulation ModelforPressurized WaterReactors(PTS-PWR),"

(received byANLJune,1983).Notethattherewasanothersetofquestions senttoyouonNovember22,1983whichreviewedthecodemodelmodifications forCombustion plantsandthefinalversion.ofXN-74-5(P)

Revision2whichwasreceivedbyANLinOctober,1983.Weareenclosing anothercopyofthatsetofquestions.

Aseparateletterandlistofquestions arebeingpreparedonourreviewofthereissueoftheExxonmethodology report,XN-74-5(P)

Rev.2,Supp.2,forPTSPWR2.Thiscompletes ourfirstroundevaluation ofallExxonmaterialreceivedbyANLtodate.AsnotedinourletterofSeptember 30,1983toyou,Exxonhadnotmetitsmilestone ofSeptember 1insubmitting thequalification

material, themethodology reportorthedescription ofcodemodifications forCEplantsasagreeduponattheJune16ANLmeeting.Asofyet,Exxonstillhasnotsubmitted theentirequalification materialpackage.Whileitwasagreeduponduringtheteleconference callofNovember7,1983betweenNRR,Exxon,D.C.CookeandANLthatthegenericreviewofPTSPWR2willcontinueasExxoncontinues tosubmitqualification materialtocompletethepackage,ANLfeelsthatitshouldbeappropriate todiscussreplacing December31,1983withanewmilestone date.IfExxonsubmitsallthenecessary materialandresponses bythemiddleofMay,themiddleofJulywouldbeanappropriate datefortheTER.r8404040304 8403thPDRADOCK050003ihPPDR1.5.Dc~rniiE~T OfE~E~T4Lhii<RsiTy ofCkic~AR<jO~~EU'aafRSITIES ASSO(,iaTIOx J.Guttmann2March6,1984Ifyouoryourcolleagues haveanyquestions, pleasecontactus.Yourssiney,T.Y..eiLightWctorSytemsAnalysisReactorAnalysisandSafetyDivisionPaul.Abramson, ManagerLightWaterReactorSystemsAnalysisReactorAnalysis5SafetyDivisionPBA:TYCW:kr Enclosures cc:R.Mattson,Director, DivisionofSystemsIntegration, NRC/NRRB.Sheron,Chief,ReactorSystemsBranch,NRC/NRRR.W.Houston,Assistant DirectorforReactorSafety,NRC/NRRS.M.Boyd,NRC/NRRJ.Carter,NRC/NRRB.L.Grenier,NRC/NRRW.Jensen,NRC/NRRN.Lauben,NRC/NRRL.W.Deitrich, RASR.Avery,RASLWRSystemsAnalysisSectionRASFiles:SM627,A15

~~

FirstRoundguestions:

ExxonPrairieIslandUnit1SGTRIncidentBenchmark AnalysisP1.Provideacomparison againstdatafortheremainder oftransient fortheperiodincluding thetripandfor200secondsbeyondthetripforwhichdataisavailable.

Thisisabenchmark calculation and'otalicensing submittal.

ThereactortripportionwilltestoutthePTSPWR2modelsunderrealplantcircumstances forwhichExxonisplanningtousethecode.The10%loadreduction phaseforwhichExxonsubmitted resultsisaverymildtransient.

2.f'rovidealistofinitialconditions comparing datawithcodevalues.3.a)Whereistime=0ofthecomputation inthesequences ofevents?b)Submitatableoftheeventsequencecomparing datawiththecodepredictions.

~3.0Q~"Thegeneralassumption ofsymmetrybetweenloopswasmadetosimplifycurrentcalculations."

Whatdoesthisstatement meanintermsofspecificmodelling items?Listthedifferences inmodelling whichanasymmetric simulation wouldrequire.5.Explaihthechoiceforinitialsteamflow/feedwater flowgiventhedifferences inplantnominaloperating conditions data.3.16.Justifytheequationusedfortheleakratewhichisdescribed asa"Henry-Fauske basedmodel."3.37.Explaintherationale forthepressurizer heatlossassumption.

~3,48.Justifytherampratesusedforloaddemand,steamdemandandfeedwater enthalpy.64.09.Itisnotclearhowthepowerreduction isbeingeffected.

Isnegativereactivity actuallybeingfedbackintothepointkineticsequationoristhepowerbasically inputbythecontroller asafunctionoftime?Clarify.10.InFig.3.4itappearsthatthecalculated TaveisrisingwhilethemeasuredTaveappearstobedecreasing at-t=220seconds.Explainthisdivergence.

11.a)"Thesteamflowdemandisessentially inputintoPTSPWR2forthisanalysis."

Clarify.b)Exxonbelievesthatthesteamflowdataneedstobeshiftedintime.Howwouldthisbeconsistent withthepressurizer plateaudatashowninFigs.3.7and3.8?c)Showthecomparisons fortheunshifted case.12.a)Whichlooparethesetemperature comparisons for?b)Loopsaretypically instrumented withmorethanonethermocouple.

Ifotherdataexistsprovideacomparison.

13.Whatistheeffectofthediscrepancy inthetransient feedwater flow?14.Exxonclaimsthattheflowdataispoor;thatthetemperature dataisinconsistent; andthattherampdataisunavailable.

Whatvaluethenisthisbenchmark analysis?