Polarizable force field parameterization and theoretical simulations of ThCl -LiCl molten salts.

Recycle of thorium is an essential process in the thorium-uranium closed fuel cycle of molten salt reactor (MSR). Pyrochemical treatment of spent nuclear fuel using chloride molten salts as medium has been considered as a promising method. In this article, we performed molecular dynamics simulations on the ThCl LiCl molten salts using a polarizable force field parameterized by us from first-principles calculations. The microscopic structures and macroscopic properties at different compositions were investigated using the developed force field to understand the structure/property relationship in the mixture. The differences between ThCl LiCl and ThF LiF MSs are compared to understand the behaviors of Th in the fluoride-chloride mixed media. In the molten fluorides, the coordination number of Th is larger, and the resulting more shared anions lead to lower ThF dissociation barrier and shorter lifetime of the Th first solvation shell. Our results also indicate the Pauling's structural rules for crystals can be used to rationalize the local structures in molten salts. © 2018 Wiley Periodicals, Inc.