Public support has continued for fusion energy due to its potential as a clean, safe source with little environmental impact. To make this hope a reality, fusion reactors and associated equipment must be made from materials that do not become highly radioactive when exposed to neutrons from the fusion reaction. Many common materials like stainless steels, however, can become and stay radioactive for long periods of time when exposed to the fusion reaction. Vanadium alloys do not have this radioactivity problem and also have acceptable strength and other properties for making fusion devices. However, little is known about welding vanadium alloys since their use has been limited to date. Preliminary work has shown that vanadium alloys react rapidly with oxygen and nitrogen and degrade when heated in their presence, common in many welding processes. This requires that vanadium alloys be welded in an air-free environment, such as in a vacuum or inert gas. This is expensive and difficult to do, particularly for large structures. Preliminary work with resistance welding shows vanadium alloys may be successfully welded in air without the oxidation problem. In Phase I resistance welded samples made from vanadium alloy will be made and tested. The conditions for making high-strength welds will be determined. In Phase II, components that are applicable to near-term and long-term fusion reactors and components will be fabricated and extensively tested.
Commercial Applications and Other Benefits as described by the awardee:The expected benefits of resistance welding vanadium alloys are that high quality welds will be made faster and less expensively than with other processes, and this process will have a higher probability of success than other welding processes. As costs are controlled at early stages in fusion energy development, the commercialization of this power source becomes more probable.
