Author/Authors :
C.Aguirre، نويسنده , , D.Caruge، نويسنده , , F.Castrillo، نويسنده , , G.Dominicus، نويسنده , , Paul J. Geutjes، نويسنده , , V.Saldo، نويسنده , , T.H.J.J.vanderHagen، نويسنده , , D.Hennig، نويسنده , , M.Huggenberger، نويسنده , , K.C.J.Ketelaar، نويسنده , , A.Manera، نويسنده , , J.L.Munoz-Cobo، نويسنده , , H.-M.Prasser، نويسنده , , U.Rohde، نويسنده , , E.Royer، نويسنده , , G.Yadigaroglu، نويسنده ,
Abstract :
Abstract
FromthebeginningofBWRtechnologyitwasrealizedthataBWRcanbecomeunstableunderparticularcircumstancescausedbyafeedbackbetweenthethermal-hydraulicsandtheneutronics.Thisinstabilitycanresultinoscillationsofthepowerandtheflowrate,whichisanunwantedphenomenon.
TheNACUSPprojectaddressesthestabilityissuesincurrentandfutureBWRsbyexpandingthebasicunderstandingthroughwellstructuredtestingandanalysesofexperimentaldata,byanalysesofexistingoperationalstabilitydatafromthreedifferentEuropeanreactors(Forsmark,Leibstadt,Cofrentes),byapplyingthisknowledgeviaefficientmodelsandvalidatedcomputercodestooperatingreactorsandreactordesigns,andbydevelopinggeneralguidelinesforreactoroperationanddesignonhowtoavoidBWRinstabilities.
Inordertocovertheparameterrangeasefficientlyaspossible,fourexisting,sophisticatedthermohydraulictestfacilities(CLOTAIRE[Gouirand,J.M.,1988.CLOTAIREProgram,descriptionandmanufacturingofthemock-up,CEACadarache,DRE/STRE/LGV88–876.]DESIRE[vandeGraaf,R.,vanderHagen,T.H.J.J.,Mudde,R.F.,1994.Two-phaseflowscalinglawsforasimulatedBWRassembly.Nucl.Eng.Des.148,455–462.]CIRCUS[deKruijf,W.J.M.,vanderHagen,T.H.J.J.,Mudde,R.F.,2000.CIRCUS;anaturalcirculationtwo-phaseflowfacility,EurothermSeminarNo.63,6–8September1999Genoa,Italy,391–395]andPANDA[Dreier,J.,Huggenberger,M.,Aubert,C.,Bandurski,T.,Fischer,O.,Healzer,J.,Lomperski,S.,Strassberger,H.-J.,Varadi,G.,Yadigaroglu,G.,1996.ThePANDAfacilityandfirsttestresults,Kerntechnik61,214–222])havebeenselected.Toextrapolatefromsmall-scaleseparate-effecttestingconditionstofull-scaleintegralreactorconditionsoneneedstorelyontheperformanceofcomputercodes(MONA[Hoyer,N.,1994.MONA,a7-EquationTransienttwo-phaseflowmodelforLWRdynamics,ProceedingsoftheInternationalConferenceonNewTrendsinNuclearSystemThermohydraulics,pp.271–280],ATHLET[Krepper,E.,Prasser,H.-M.,1999.NaturalcirculationexperimentsattheISB-VVERintegraltestfacilityandcalculationsusingthethermal-hydrauliccodeATHLET.Nucl.Technol.128,75–86],RAMONA-3(-5)[Grandi,G.,Hoyer,N.,Belblidia,L.,1998.Two-fluidthermalhydraulicscapabilitiesofRAMONA-5,ProceedingsoftheInternationalConferenceonthePhysicsofNuclearScienceandTechnology,October5–8,1998,LongIsland,NY,USA,1621–1625],LAPUR-V[Otaduy,P.J.,March-Leuba,J.,1990.LAPURUserʹsGuide,NUREG/CR-542,ORNL/TM-11285],DWOS,FLICA[Toumi,I.,Bergeron,A.,Gallo,D.,Royer,E.,Caruge,D.,2000.FLICA-4:athree-dimensionaltwo-phaseflowcomputercodewithadvancednumericalmethodsfornuclearapplications,Nucl.Eng.Des.200,139–155],SAPHYR,RELAP5/MOD3[IdahoNationalEngineeringLaboratory,1995.RELAP5/MOD3CodeManual,Vols.1–6,INEL-95/0174,NUREG/CR-5535],TRAC-BF1[IdahoNationalEngineeringLaboratory,1992.TRAC-BF1/MOD1;anadvancedbest-estimatecomputerprogramforBWRaccidentanalysis,Vols.1–3,EGG-2626,NUREG/CR-4356].ForspecificitemsCFDcodesareappliedaswell.WithinNACUSPalinearstabilityanalysistoolisdeveloped.
Fourofthethreeexperimentalfacilitieswithintheprojecthaveyieldedalarge,uniquedatabase.
Natural-circulationandstabilitycharacteristicsatnominalpressurewerecollectedfromextensiveexperimentsattheDESIREfacility.Low-pressurecharacteristicsweremeasuredatthePANDA(largescale)andtheCIRCUS(smallscale)facility.
Thephenomenaencountered(flowrateandstabilitytrends,theoccurrenceofflashinginducedoscillations)canbeexplainedfrombasicphysicalmodelsandarenowwellunderstood.
Severalthermal-hydrauliccodeshavebeenbenchmarked—somesuccessfully,otherswithlimitedsuccess—againstthesedata.
TheCLOTAIRE(nominalpressure,largescale)facilityhasbeenmodifiedandisnowreadyforexperiments.
NuclearpowerplantdatafromthreeBWRs(Cofrentes,ForsmarkandLeibstadt)havebeencollected.AverycompletesetofreactordatawasobtainedfrommeasurementsattheLeibstadtBWRduringcycle-19.Duringthistest,whichwasperformedwithintheNACUSPproject,safereactoroperationwasdemonstratedatextremeconditions,coveringtheentirepower-flowmap.
State-of-the-art,coupledthermal-hydraulic—neutronicscodesarebeingbenchmarkedonthesedata.
Thedevelopmentofaneasytouse,rapidandefficientanalyticaltoolforparametricstudiesonBWRstabilityisinprogress.
ThelastyearofNACUSPwillbedevotedtofinalisingthebeforementionedactivitiesandtousethetoolsdevelopedandtheexperienceobtainedfordevelopinggeneralguidelinesfordesigningandoperatingBWRs.
