A revised and expanded liquid metal property library for MELCOR

The liquid metal thermophysical properties library in MELCOR for Fusion has been comprehensively revised. In addition to the existing liquid metals Li, Na, and NaK, recently developed equations of state and updated transport properties for PbLi and Sn have been implemented, and a new SnLi alloy (80% Sn, 20% Li) equation of state has been developed and added. SnLi has been investigated in a variety of experiments, but its thermodynamic properties (e.g. density, specific heat, and sound speed as a function of temperature) have not yet been determined. We have therefore predicted these based on the pure component equations of state and a mixing rule for these elements based on chemical activity measurements; these calculations are described in the paper. The revised code also dispenses with the prior method of computing properties by interpolating property tables during execution, in favor of direct computation from the equations of state and their derivatives, the result being up to a factor of two speed increase in code execution in some test cases.