TrendsandneedsinexperimentationandnumericalsimulationforLWRsafetyOriginalResearchArticle

heverycomplexphenomenathatneedtobeconsideredinsafetyanalysesrequireuseofsophisticatedanalyticaltools.Basically,one-dimensional(1D)systemcodeshavebeenusedforalongtimeandhavereachedadegreeofmaturity.Thereare,however,limitstotheircapabilitiesandfurtherdevelopmentsareunderway;theseareoutlined.Thedevelopmentofnewgenerationsoftoolsandmethodscanprofitfromtheavailabilityofincreasinglypowerfulcomputersandadvancesinmultiphaseflow,informationtechnologyandnumericaltechniques.Three-dimensional(3D)situationsneedalsotobeaddressedmorefrequentlynow.CertaindevelopmentsinthesedirectionsthatarealreadytakingplaceinvariousEURATOMresearchprogramsandelsewherearebrieflyreviewed;casestudiesofapplicationsarediscussedandlessonsdrawn. FuturesafetyanalysesfornuclearpowerplantsmayincludeuseofComputationalFluidDynamics(CFD)forpartsoftheprimarysystemandthecontainment.Firstapplicationsinthisdirectionhavealreadybeenmade.Although3D,single-phaseCFDcomputationsarecommonplace,thesizeofthesystemsconsideredmakethesequitechallenging.Therealchallengeslie,however,intwo-phaseflowCFDapplicationsthatarestillattheirveryinfancy.Couplingofneutronicandthermal-hydrauliccodesisalsonecessaryforcertainproblems.