Chemical diffusion coefficient calculation of U3+ in LiCl-KCl molten salt

Self-diffusion coefficient denotes the intrinsic diffusion of elements without the chemical gradient; generally, it is different from the chemical diffusion coefficient that is used in Fick's law. However, the self-diffusion coefficient can be converted to the chemical diffusion coefficient by considering the concentration-dependent activity coefficient of solute. In this study, the multiple time origins method was applied to calculate the self-diffusion coefficient of U3+ in LiCl-KCl eutectic salt at different temperatures and concentrations. The chemical diffusion coefficient was obtained based on the calculated results and thermodynamic theory. Calculated results show that self-diffusion coefficient decreases with concentration however chemical diffusion coefficient indicates to change little initially but appears to increase followed by decrease later within the concentration range of 0-3 at%.