Author/Authors :
F.Reitsma، نويسنده , , G.Strydom، نويسنده , , Ryan A. DeHaas، نويسنده , , K.Ivanov، نويسنده , , Bismark Tyobeka، نويسنده , , R.Mphahlele، نويسنده , , T.J.Downar، نويسنده , , V.Seker، نويسنده , , H.D.Gougar، نويسنده , , D.F.DaCruz، نويسنده , , U.E.Sikik، نويسنده ,
Abstract :
Insupportofthepebblebedmodularreactor(PBMR)VerificationandValidation(V&V)effort,asetofbenchmarktestproblemshasbeendefinedthatfocusoncoupledcoreneutronicsandthermal-hydrauliccode-to-codecomparisons.Themotivationisnotonlytotesttheexistingmethodsorcodesavailableforhigh-temperaturegas-cooledreactors(HTGRs),butalsotoserveasabasisforthedevelopmentofmoreaccurateandefficienttoolstoanalysetheneutronicsandthermal-hydraulicbehaviourfordesignandsafetyevaluationsinfuture.
ThereferencedesignforthePBMR268benchmarkproblemisderivedfromthe268MWPBMRdesignwithadynamiccentralcolumncontainingonlygraphitespheres.Severalsimplificationsweremadetothedesigninordertolimittheneedforanyfurtherapproximationswhendefiningcodemodels.Duringthisprocess,carewastakentoensurethatalltheimportantcharacteristicsofthereactordesignwerepreserved.ThedefinitionandinitialphasesofthebenchmarkwereperformedunderacooperativeresearchprojectbetweenNRG,PennStateUniversity(PSU)andPBMR(Pty)Ltd.However,participationhasbeenextendedtoincludePurdueUniversityandINL.Allcontributionstothebenchmarkeffortweremadein-kindbytheparticipatingmembersincludingtheparticipationinfourbenchmarkmeetingsoveraperiodof3years.BasedontheworkperformedinthisbenchmarkthePBMR400MWdesignwithfixedcentralreflectorhasbeenacceptedasanOECDbenchmarkproblemandworkhasalreadystarted.
Inthispaper,thebenchmarkdefinitionandthedifferenttestcasesaredescribedinsomedetail.Phase1focusesonsteady-stateconditionswiththepurposeofquantifyingdifferencesbetweencodesystems,modelsandbasicdata.Italsoservesasthebasistoestablishacommonstartingconditionforthetransientcases.InPhase2,thefocusisonperformingcoupledkinetics/corethermal-hydraulicstestproblemswithacommoncross-sectionandmaterialpropertysets.Thesixeventsselectedaredescribed,andexamplesofsomeresultsareincludedtoillustratethebehaviourofthetransients.ThefinalresultsofthisworkwillbepublishedinanNRGreportandthefocuswillmovetotheOECD400MWbenchmarkproblem.
