Fusion energy could provide the UK with safe, baseload, and zero-carbon electricity. A major challenge to its implementation is the development of advanced shielding materials that can protect parts of the fusion reactor from radiation damage. Tungsten carbide ceramics are front-running candidate materials for this due to their excellent thermal, mechanical, and shielding properties, and they are available on industrial scale (e.g. in cutting tools). However, the current industrial formulations contain cobalt additives and other impurities that are unsuitable for fusion applications due to their tendency to form hazardous radioactive isotopes under irradiation. An alternative, low-activation ceramic material composition will be established and characterised. A key project driver is to develop a greater understanding of the impurities distributed within the microstructure, e.g. are they in solid solution, segregating to grain boundaries, or tied up in nanoscale precipitates? The microstructure of the material will be studied in great detail looking at the presence of secondary phases and how it relates to the processing conditions.
Answering these questions is critical if a low activation shielding material is to be implemented. To maximise project impact, it is supported by H.C. Starck Tungsten, an industrial supplier of tungsten carbide who will provide powders; and by the UK's fusion science laboratory (UKAEA) who will build their 'STEP' reactor by 2040.