Local structure and thermophysical properties of the molten salt FNaBe through ab initio molecular dynamics and experimental measurements

NaF-BeF 2 molten salt has been proposed as one of the potential solvents and coolants for molten salt reactor due to its pertinent properties and satisfactory neutron capture cross-section. The experimental measurements combined theoretical simulations were employed to investigate comprehensive information on the structures and thermophysical properties of molten NaF-BeF 2 . Specifically, the specific heat capacity, density, and viscosity of NaF-BeF 2 systems were determined using custom devices. Using the fitting relationships and simulations, the extrapolative data were also successfully obtained under the critical temperatures. The local structure including bond lengths, coordination structures and the potential of mean force, was further simulated by ab initio molecular dynamics in the temperature range of 673–1123 K. The coordination of Na and Be is predominantly characterized by six-fold and four-fold, respectively. Moreover, of Be-F bond is 7 times than Na-F bond, which suggests the stronger stability of Be-F bond in molten NaF-BeF 2 .