Radiation damage in ceramic plasma-facing materials

The present status of the studies of radiation damage of plasma-facing materials is reviewed. Emphasis is placed on the extent of the understanding in terms of the critical issues for materials in use as plasma interactive components. Understanding of the basic problems of radiation effects, which are important for long term development of fusion reactors, is also emphasized. It is pointed out that for low-Z materials radiation damage by fission neutrons is a good measure of the effects of radiation damage by fusion neutrons. The understanding of the fission neutron damage of major candidate materials is surveyed. Existing data on the effects of transmuted helium gas in beryllium are inferred and the data needs for the He effects on graphite are stressed. For radiation damage by plasma particles, the importance of understanding of the dynamic behaviors of the materials which are composite because of redeposition and hydrogen implantation. Some of the features of such composite materials under radiation are presented. (orig.)