Bonding Fusion Reactor Materials

Details

Supervisor: Russell Goodall (University of Sheffield)

While there are a number of competing reactor concepts, it is certain that any fusion power system will be a complex device, making use of the most highly optimised materials possible to achieve the best performance.  One of the effects of this is that there will be a need to join together many different materials, likely including combinations for which joining strategies have not previously been developed.

Among the routes that can be explored for joints between two different materials, especially those with very high melting temperatures (as is required for many parts of a fusion reactor) are processes such as brazing or diffusion bonding.  In these, the surfaces to be joined are brought together at temperature, with the application of an addition filler metal (brazing) and/or pressure (diffusion bonding).  While the processes are well understood in general terms, and widely applied in other situations, when bonding fusion reactor materials (including reduced-activation steels, tungsten, vanadium and copper alloys), there is much that is unknown about the formation of bonds and the performance under service conditions.

This project will increase the understanding of these joining methods for fusion-relevant materials, with scope to focus on specific materials or components of particular interest.  Joints will be experimentally created and characterised, in the as-made form and after exposure to conditions that simulate aspects of the service such joints will have to withstand.  We will explore structural changes at the joint and around it, seeking to identify defects that are harmful for the properties, as well as the mechanical and thermal performance of the joined parts.  As well as the initial creation of the joints, methods that could be used for in-situ repair of joint defects may also be studied.  The information obtained in this project will be of use across different reactor designs, as manufacturing routes are developed for fusion systems.

The project would be mainly based in Sheffield.  We would anticipate there being opportunities for short term travel nationally and internationally, to other research facilities, collaborators, and conferences. These would not be compulsory, and engagement with such opportunities would be determined both by the direction of the research, and the situation of the researcher themselves.