Materials challenges for successful roll-out of commercial fusion reactors

Abstract

As members of the UK fusion community (covering national laboratories, academia and industry), we approached various colleagues to put together articles for this special issue of the Journal of Physics: Energy covering the materials challenges through to successful roll-out of fusion reactors. This paper serves to introduce the special issue and gives our opinion on the key challenges, many of which are covered in more detail in the submitted papers. Others may have differing opinions about what the key challenges are, but what we will all agree on is that they are substantial and will require sizeableresources to be addressed. Further, while we are all UK-based, all humankind will benefit from successful commercial roll-out of fusion for energy production, and the effort has been and will continue to be global. Fusion has entered the engineering era. Moving from plasma science to experiments demonstrating the benefits of modified torus shapes and advanced divertor geometries, the ‘field’ has become an ‘industry’. Investors now focus on whether superconducting magnet joints are feasible in large tokamak designs and how to deliver net energy to the grid. As with all technology trajectories, materials (both structural and functional) are the key enablers. For fusion materials, the three major challenges remain resilience to the combined damaging effects of tritium, transmutation and neutron bombardment (a veritable ‘triple whammy’), achieving suitable irradiation strategies for adequate damage studies (with optimal use of modelling as complementary science) and defining material safety and waste guidance in an era of evolving regulation. In the following, we highlight issues around ‘the triple whammy’, the resulting need for testing facilities and modelling proxies, and aspects of regulating materials in, and waste generated from, operating fusion reactors.