Critical evaluation and thermodynamic optimization of the (U + Bi), (U + Si) and (U + Sn) binary systems

• Critical literature review and evaluation of phase equilibria of the (U + Bi), (U + Si) and (U + Sn) systems were presented.
• The (U + Sn) binary system has been assessed by using the CALPHAD for the first time.
• (U + Bi) and (U + Si) binary systems were re-optimised basing on present literature review and evaluation.
• Thermodynamic database of the (U + Bi), (U + Si) and (U + Sn) binary systems can serve for nuclear materials development.

A complete literature review, critical evaluation and thermodynamic optimization of the phase diagrams and thermodynamic properties in the (U + X) (X: Bi, Si and Sn) binary systems are presented. The CALPHAD method was used for the thermodynamic optimization, the result of which can reproduce all available and reliable experimental phase equilibria and thermodynamic data of the (U + X) (X: Bi, Si and Sn) binary systems using a set of thermodynamic functions. The modified quasi-chemical model in the pair approximation (MQMPA) was used for modelling the liquid solution. The Gibbs energies of all terminal solid solutions and intermetallic compounds were described by the compound energy formalism (CEF) model. All reliable experimental results have been reproduced within measurement error limits. A self-consistent thermodynamic database has been constructed for these (U + X) binary systems; this database can be used as a guide for nuclear materials research.