Heat capacities of rare earth fluorides

Heat capacity is one of the very important factors in context of a power reactor. It governs the heat content of the fuel material and the coolant. It also governs the heat transfer from fuel to the primary coolant and from primary coolant to the secondary coolant. The molten salt reactor (MSR) has fuel (UF₄, PuF₃, ThF₄ etc.) and coolant coexisting as fluoride molten salt mixture. Since, lanthanides are significant fission products, after fission there will be significant amount of lanthanide fluorides in the core. So, the design and operation of an MSR requires the knowledge of heat capacities fuel material, coolant material and the fission products. There is a lack of literature on direct measurement of heat capacity. Spedding and Henderson have reported heat capacities (from 400 K to 1850 K) of YF₃, LaF₃, PrF₃, NdF₃, GdF₃, HoF₃ and LuF₃ calculated from enthalpy increment values obtained experimentally. In the present work, the heat capacities of LaF₃, NdF₃ and YbF₃, from 303 K to 673 K have been determined experimentally using a Setaram-DSC 131