Recent progress of vanadium-based alloys for fusion application

Low-activation vanadium alloys, with the reference composition of V–4Cr–4Ti have been considered as one of the most promising candidate materials for structural components such as the blanket in future fusion reactors, thanks to their excellent neutron irradiation resistance, superior high-temperature mechanical properties, and high compatibility with liquid lithium blankets. The self-cooled liquid lithium blanket using structural materials of vanadium alloys is an attractive concept because of the high heat transfer and high tritium breeding capability. After more than 2 decades of research, technological progress has been made in reducing the number of critical issues for application of vanadium alloys to fusion reactors. In this paper, the recent research and development activities of vanadium alloys are summarized, including significant progress achieved on fabrication technology and composition optimization, coating and corrosion, improved understanding of irradiation effects upon microstructure and material properties, retention of hydrogen isotopes, as well as advancements in joining and welding. In particular, the fact that recent products from China, Japan, US and France showed similar properties which meant the fabrication technology has been almost standardized.