Vanadium alloys for fusion applications

Although a fusion power plant does not generate fission products, its structural components can become radioactive as a result of nuclear transmutations within the component materials from exposure to neutrons. The level of induced radioactivity in these structures controls the environmental impact of the entire system. To fully exploit its environmental attractiveness, fusion energy systems will require low-activation structural materials, which have low levels of induced radioactivity. The United States Fusion Materials Program of the Department of Energy`s Office of Fusion Energy Science is pursuing the development of low-activation materials, including vanadium alloys, ferritic-martensitic steels, and SiC/SiC composites. Vanadium alloys are under consideration because they have the potential for minimum environmental impact and provide properties superior to those of steels and other candidate materials. Extensive research and development over the past 15 years has resulted in a basic understanding of the behavior of vanadium alloys in a fusion environment. The paper discusses alloy compositions, performance characteristics, safety and environmental impacts, and compatibility issues.