BoilingexperimentsforthevalidationofdryoutmodelsusedinreactorsafetyOriginalResearchArticle

Thecoolabilityoffragmentedcoriumisamajorissueinreactorsafety.Sincethelong-termcoolabilityofsuchparticlebedsislimitedbytheavailabilityofcoolantinsidethebedandnotbyheattransferlimitationsfromtheparticlestothecoolant,thepressurefieldinsidethedebrishasastrongeffectonthecoolingpotentialinmulti-dimensionalcasesasexpectedinsevereaccidentsinlightwaterreactors(LWR).Therefore,thedeterminationofthepressurefieldfortwo-phaseflowsinporousmediaisonecentralpointofinterest. Inthiscontextsimulationmodelsandinparticulardryoutmodelsweredevelopedforreactorsafetyanalyseswhichhavetobevalidatedbyreliableexperimentaldata.Therefore,basicexperimentalinvestigationshavebeencarriedoutwithinductivelyheatedsteelballsof6or3mmdiametertoprovideadatabaseforthevalidationandmodificationofthefrictionlawsincludedinthesedryoutmodels. Theperformedboilinganddryoutexperimentsshowclearlythatmodelswithouttheexplicitconsiderationoftheinterfacialdragcannotpredictthepressuredistributioninsideaboilingparticlebed,notevenqualitatively.Againstit,modelswithanexplicitconsiderationoftheinterfacialdragcandescribethedistributionofpressureinsideaboilingparticlebed.