Safety and environmental challenges in materials selection

The single most significant factor determining the safety and environmental characteristics of a fusion power plant is the choice of near-plasma materials. The three purposes of the paper are to (a) very briefly summarize the key safety issues, (b) examine the current state of knowledge concerning which elements and material compositions appear to be the best selections from the safety perspective, and (c) provides some thoughts on future directions in materials research and selection. With the most conventional materials currently being pursued, it is likely that an attractive fusion energy source will be possible. However, it is also likely that further innovation can lead to superior materials. Enough is known to provide guidance on future directions so as to help fulfill fusion's highest potential. Preferred materials include helium, lithium, and flibe (LiF-BeF2) as coolants; certain ceramics, lithium, and flibe as tritium breeders; silicon carbie, vanadium alloys, and ''clean'' ferritic steels as structural materials. (orig.)