The ferritic (martensitic) steels and the austenitic stainless steels are being considered for use as first wall and blanket structural components for fusion reactors. Tensile specimens of normalized-and-tempered 9 Cr-1 MoVNb and 12 Cr-1 MoVW steels, normalized-and-tempered and isothermally annealed 2-1/4 Cr-1 Mo steel, and 20%-cold-worked type 316 stainless steel were irradiated at approximately 50/sup 0/C to damage levels of up to about 9 displacements per atom (dpa) in the High Flux Isotope Reactor (HFIR). The preirradiated microstructures of the 9 Cr-1 MoVNb and 12 Cr-1 MoVW steels were a tempered martensite; the microstructure of the normalized-and-tempered 2-1/4 Cr-1 Mo steel was tempered bainite, and that of the isothermally annealed 2-1/4 Cr-1 Mo steel was primarily polygonal ferrite
