Computationalfluiddynamicsanalysisofspallationtargetforexperimentalaccelerator-driventransmutationsystemOriginalResearchArticle

OneofthekeymilestonesintheroadmapoftheEuropeanaccelerator-driventransmutationsystem(ADS)isthedesignandconstructionoftheEuropeanexperimentalADS(XADS).Thewindowspallationtargetunitinthelead–bismutheutectic(LBE)cooledreactorsystemisoneofthebasicoptionsconsideredinthepreliminarydesignstudyofXADS(PDS-XADS).Thispaperpresentsthecomputationalfluiddynamics(CFD)analysisandthemainresultsachievedforthisoptionfocusingonthecoolabilityofthewindow.Steady-stateaswellastransientbehavior,includingbeaminterruptsandthreemajoraccidentscenarios,hasbeenanalyzedusingtheCFDcodeCFX5.6withanadvancedturbulencemodel.Therequiredboundaryconditionswereprovidedbyaone-dimensionalsystemcode.BasedontheCFDanalysis,thewindowgeometrywasmodifiedinordertoachievesufficientcoolingcapabilityofthewindowundernormaloperatingconditions.Thetransientbehaviorofthewindowtemperatureunderbeamtripconditionsshowstheimportanceofthebeaminterruptdurationtothethermalstressloadofthewindowstructuralmaterial.Furthertransientanalysisofthreemajoraccidentalscenarios,i.e.,beamfocusing,lossofheatsink,andbeamintensityjump,indicatesthatthebeamfocusingaccidentgivesthemostserioussafetyconcern.Inthiscase,windowfailureoccursinlessthan1safterthestartofthebeamfocusing.