New Insights into the Chemistry of Advanced Molten Salt Nuclear Fuels—Experimental and Computational Studies at the TU Delft

Generation-IV Molten Salt Reactors (MSRs) are received increasing attention worldwide as key players for the energy transition, providing sustainable and low-carbon energy supply. One main challenge for their future commercialisation is a comprehensive understanding and modelling of the molten salt fuel chemistry, enabling a through safety assessment. MSR concepts around the world are based either on a chloride or fluoride molten salt mixture. Some of the main questions that need to be addressed are the fission products chemistry and evaluation of the source term in molten salts, the chemical interaction of the fuel salt with structural materials, or strategies for management of high level waste within a fleet of MSRs. I will show some of the recent insights we have gained on these advanced molten salt fuels at the TU Delft, combining experimental approaches using X-ray and neutron diffraction, X-ray Absorption Spectroscopy, calorimetry, microscopy, and modelling techniques. I will address the selection and modelling of promising fuel salt mixtures as e.g. actinide burner or thorium breeder, the effect of fission products accumulation on the fuel salt chemistry, as well as studies of the local structure of the melt, which can be directly related to the thermo-physical properties (density, viscosity etc).