Molecular dynamics simulation study on behavior of metallic ion in molten salt mixture bath

Okamoto, Yoshihiro  ; Tsuruoka, Takuya*; Yaita, Tsuyoshi; Madden, P. A.*

Behavior of very small amount of metallic ion in molten alkali chloride mixture melt is very important information in pyrochemical reprocessing of spent nuclear fuels. In the present work, mixing behavior of molten LaCl in LiCl-KCl eutectic melt was simulated by molecular dynamics simulations. It has been reported that molten pure LaCl has an 8-fold (LaCl) structure. The coordination number decreases by mixing with LiCl-KCl eutectic mixture melt and indicates a value close to 6 less than 31%LaCl composition. It suggests that molten LaCl has an octahedral coordination structure in the mixture, as shown in molten YCl systems. In the MD simulation, the mixing effect was different between LiCl and KCl. It is due to high number density of Cl ion in molten LiCl comparable to molten LaCl and strong Coulomb force introduced by a small Li ion.