TOLBIAC Code Simulations of some Molten Salt RASPLAV Exsperiments

In the frame of severe accidents studies, the behaviour of a corium pool has to be predicted. Numerous physical processes are involved in these studies, and a predictive tool is of great interest in order to investigate several situations, geometries or events. The TOLBIAC code, developed by CEA/Grenoble, is devoted to the simulation of the thermalhydraulic behaviour of a corium pool both in-vessel and ex-vessel situations, with natural convection.Some molten salt RASPLAV experiments have been simulated for the TOLBIAC code assessment. An adiabatic condition at the free surface of the molten pool is used. The comparisons between TOLBIAC calculations and RASPLAV data concern the pool temperatures, the local wall heat fluxes and the crust thickness (if any). The wall heat transfer correlations are the key parameter for the agreement between calculations and data, and are discussed. Concerning the crust thickness, the results are sensitive to their physical properties, and mainly to the thermal conductivity.