Thermodynamic properties and phase diagrams of fluoride salts for nuclear applications

This work is a critical review of the chemical–physical properties of the fluoride salts of interest in the Molten Salt Reactor project. In total five salt compositions are discussed. Two of them are choices for coolant applications (based on LiF–BeF2 and NaF–NaBF4 systems) one is considered as a heat transfer salt (LiF–NaF–KF system) whereas the other two are the main candidates for the fuels in non-moderated breeder and thermal breeder reactors, respectively (LiF–ThF4 and LiF–BeF2–ThF4 systems). For all the systems the phase diagrams are presented with the emphasis on the melting behaviour and the vapour pressure. Heat capacity, density, viscosity and thermal conductivity, as well as the solubility for actinides in case of the fuels are presented also.