Mechanical and thermal behaviour of U–Mo and U–Nb–Zr Alloys

Nuclear fuels composed of uranium alloys in monolithic and dispersed forms are being considered for research and compact power reactors due to their density properties (greater than 15 g-U/cm3) and fast heat transfer. U–Nb–Zr and U–Mo alloys are the most promising systems for plate fuel elements owing to their broad γ-phase stability field, which shows higher ductility and isotropic behaviour, allowing extensive fabrication capability. In the present work, γ-phase stabilized U–7.5Nb–2.5Zr and U–10Mo alloys were characterized by mechanical and thermal analyses for comparison of their behaviour under deformation and heat-treatment. The results demonstrate that the alloys have substantially different properties regarding deformation, kinetics phase transformation and recovery/recrystallization. The main results show that U–Nb–Zr is superior regarding fabrication capabilities although the γ-phase is less stable than U–Mo alloys.