Thermodynamic database on U-Pu-Zr-Np-Am-Fe alloy system I — Re-evaluation of U-Pu-Zr alloy system -

A thermodynamic database on a U-Pu-Zr-Np-Am-Fe alloy system is being constructed for developing metallic fuels containing minor actinides. In the first step, a ternary U-Pu-Zr alloy system is re-assessed by the CALPHAD method by taking some recent data into consideration, such as chemical activity of 8-phase for the U-Zr system, liquidus and solidus for the Pu-U system, vapour pressure of Pu in the Pu-U system and etc. Phase diagrams of three binary sub-system and a ternary system were then re-evaluated and some inconsistencies among the binary and ternary phase diagrams were adjusted by introducing some assumptions.