The development of structural materials for fusion reactors

Structural materials for first-wall and breeding-blanket components will be exposed to 14 MeV neutrons, plasma particles and electromagnetic radiation. In magnetically confined systems, the operation mode will be quasi-continuous. Typical operation conditions for next-step devices and demonstration plants will be described. The selection of suitable structural materials is based on conventional properties, their resistance to radiation-induced damage phenomena and the additional requirement of low neutron-induced radioactivity. Presently, low-activating ferritic-martensitic steels, vanadium alloys and ceramic composites are investigated as promising candidates. In the paper the present status of knowledge is reviewed and the critical issues for the different alternatives are elaborated. The necessity of an appropriate neutron source for the testing and qualification of the materials under fusion-specific conditions is also stressed.