Ceramic Materials for Fusion

The (low-atomic-number ceramic) materials carbon, SiC, Be₂C, B₄C, TiC, BN, Si₃N₄, Al₂O₃, and BeO provide a range of property values that are useful for evaluating range of applicability of low-atomic-number ceramic materials in fusion reactors. A survey of recent literature provides a base for conceptual design analyses of two first wall concepts: (a) a radiation-cooled simple plate liner and (b) a pressurized helium, forced convection-cooled tubular assembly. The first case is limited in heat load by maximum material temperature, and the second by either temperature or stress. Maximum temperatures are limited by vapor pressure or chemical reaction rates with plasma hydrogen, both resulting in release of impurities to the plasma. Silicon carbide and carbon appear most suitable for first wall materials, with estimated wall loading limits in the range from 1 to >5 MW/m² of incident 14-MeV neutrons.