Investigation of the structure and dynamics of molten salt LiF-NaF-UF4 using first-principles molecular dynamics

Molten salts are considered to play a key role in a future low-carbon economy, especially in nuclear energy and energy storage. However, very little is understood about their dynamics and thermophysical properties since the experimental investigation is difficult due to their corrosiveness and the high temperatures of interest. Currently, the state of the art to study molten salts computationally is through first-principle molecular dynamics (FPMD) simulations and machine learning (neural network potentials). In this work we thoroughly investigated the structure and dynamics of LiF-NaF-UF4 (54.5-36.4-9.1 mol%), a candidate salt for next-generation molten salt reactors, using FPMD. Structural properties such as pair distribution function and structure factor, and transport and thermophysical properties such as specific heat, density, viscosity, and diffusion were calculated. Some of the results we obtained can be directly compared to neutron scattering experiments for validation. This in-depth understanding of the salt’s properties is important to facilitate the screening of molten salt candidates in different industrial applications, and to gain insights into the dynamics of ionic liquids.