Development and evaluation of advanced materials for fusion applications

Tyler Abrams, General Atomics

The structural and functional materials used in today's short-pulse, low-fluence plasma confinement experiments, including ITER, generally do not extrapolate well to fusion power plants with a high duty cycle, implying that significant improvements over conventional nuclear materials are needed. This talk discusses two broad classes of prospective fusion materials that may provide substantial advantages over conventional nuclear-grade components: (i) advanced tungsten alloys and (ii) ultra-high-temperature ceramics, with a particular focus on silicon carbide (SiC). Fabrication methods, structure-property relationships, and irradiation damage characteristics are reviewed, including the major synergies of these materials with high temperature operation (~1000 ^oC and above). Recent activities led by General Atomics and collaborating institutions to evaluate prototypical advanced materials under high heat and plasma fluxes at the DIII-D National Fusion Facility and the PISCES linear plasma device are also discussed. Key near-term and medium-term research needs are identified, including mitigation of T retention due to diffusion and co-deposition, enhanced densification to improve thermal conductivity, advanced joining methods, and development of irradiation damage databases.