High-Temperature Viscosity Measurement of LiCl-KCl Molten Salts Comprising Actinides and Lanthanides

Physical properties of molten salt such as viscosity, density, solubility, surface tension, solubility, diffusivity, electrical/thermal conductivity, etc., are important for the design and the early fault detection of each unit processes in the pyroprocess. Among them, the viscosities of the high-temperature molten salts should be considered much more carefully when designing the plant as well as handling and transferring the molten fluid containing radioactive actinides and lanthanides from one unit process to the other in the pyroprocess. The viscosity is also related to the electrical properties and the structure of the liquids. However, there are only viscosity data of pure molten LiCl-KCl eutectic in a limited range of temperatures (890-1080 K). Therefore, interpolation and extrapolation are required to determine the viscosity at a specific process condition, for example, at ca. 773 K for the transfer of molten salt in the pyroprocess. In addition, there have been no previous reports on the viscosity of LiCl-KCl eutectic containing a wide concentration range of actinides and lanthanides such as uranium (U), neodymium (Nd), cerium (Ce), and lanthanum (La), which are of major interests regarding the recycling of LiCl-KCl molten salts