On the development of low-activation materials for fusion reactors

Abstract

The induced radioactivity of first wall materials was evaluated by the IRAC code. Co, Ni, Cu, Nb, and Mo are strictly limited in concentration. The long-lived nuclide, 26A1, from Al can not be ignored for a long operation of ≧ 10 MW y m −2. The low activation materials are selected by the evaluation and materials properties of candidate alloys designed from the viewpoint of low activity were studied. The phase stability and its effect on toughness of Fe-Cr-W steels were investigated. δ-ferrite was shown to be eliminated for improving toughness. The concentration of W should be below 3% in the 9Cr-0.1C and 1.4% in the 12Cr-0.1C steels. The lowest activity material, C/SiC composite, was produced by the CVI method. CVI was shown as one of the methods to improve the toughness of ceramics composites.