EXPERIMENTAL COMPARATIVE-STUDY OF ACTIVATION OF STAINLESS-STEELS BY 14 MEV NEUTRONS

The activities induced by D-T fusion neutrons in samples of stainless steels considered as structural materials for perspective fusion devic es were experimentally investigated. The total activity of the Russian ferritic steel 10H9VFA, which is one of the candidates for the first wall structural material of the Russian Demo design, is compared with the total activities of two SS316 samples and of the ferritic steels M ANET-II (Germany) and F82H (Japan). The experiments were carried out a t the high-intensity neutron generator SNEG-13. Samples were simultane ously irradiated at two positions corresponding to mean neutron energi es of 14.93 and 14.37 MeV. The measurements have shown that for coolin g times up to a few months, the total specific activity of the investi gated steels is mainly determined by reactions on Ni, Cr and Fe. The a ctivity of the steels 10H9VFA and F82H is slightly less than that of M ANET-II, the activity of which, in turn, is significantly less than th at of SS316 and AISI 316 LN. This arises mainly from the lower content s of nickel in 10H9VFA and F82H. For all of the considered steels the activity is higher at the larger mean neutron energy, indicating the i mportant role of (n,2n) reactions for steel activation at neutron ener gies of 14-15 MeV. The experimental data are to be used for direct com parison of activation characteristics of structural materials as well as for the validation of activation data. (C) 1998 Elsevier Science S. A. All rights reserved.