The Application of CALPHAD Calculations to Uranium-Based Metallic Nuclear Fuels

The thermodynamic calculation and optimization on the binary and ternary systems consisting of Mo, Pu, Th, Ti, U, V and Zr used in metallic nuclear fuel are systematically reviewed. By combining the optimized systems in literatures and present assessment of U-Mo-Zr ternary system, the thermodynamic databases of U-Mo-based and U-Zr-based nuclear fuels were established based on the Calculation of Phase Diagram (CALPHAD) method. The stable phase diagrams and dynamical phase diagrams under irradiation were reviewed based on the database. As the examples for the application of the two thermodynamic databases, the effect of alloying elements on the stability of bcc (γU) phase in different ternary and multicomponent alloys were discussed, which can provide essential theoretical guidance for the design Uranium-based metallic nuclear fuels.