fluid flow behaviour during free vibrations of a mono-hexagonassembly validation of 3-d navier-stokes model in cast3m withexperiments on pise-1a

International audienceIn the scheme of French ASTRID (Advanced Sodium TechnologicalReactor for Industrial Demonstration) project, fluidstructure interaction phenomenon involved in the dynamic behaviourof core flowering, which could happen during seismicevents, are of high interest. Also core flowering behaviour isconsidered as the main initiating event for the four SCRAMsthat happened in PHENIX reactor during 1989 to 1990. Monoassemblytesting facility PISE-1A and multi-assembly experimentalmock-up PISE-2C were built in CEA for further researchespecially focusing on damping. A series of free-vibration experimentswith different conditions has been performed on PISE-1A.Corresponding 3-D simulations with Navier-Stokes model implementedwith CAST3M code have been performed for interpretation,validation and verification with the experiments. Addedmass effects on damping and frequency involved in the behaviourof the assemblys motion during free vibration tests with differentphysical conditions, including liquid height, viscosity and density,have been studied. Uncertainty sources from non-linearitiesduring experiments, data analysis methodologies and simulationstability have been investigated