Transmutation of plasma facing materials by the neutron flux in a DT fusion reactor

The neutron induced transmutations, gas production, activation, atomic disp lacements and afterheat have been calculated for several potential low- and high-Z first wall materials in a DT fusion reactor. The neutron spectra ta ken are those calculated for the first wall of the shielding blanket propos ed for the International Thermonuclear Experimental Reactor (ITER). For low Z materials the production of hydrogen and helium isotopes dominate, while for high Z materials activation and afterheat dominate. Far a total flux o f 14.1 MeV neutrons corresponding to a wall load of 1 MW a m(-2), the triti um production in a 1 cm thick low Z material layer of the first wall is of the order of 10(16) - 10(14) cm(-2), while the calculated He concentrations are of the order of similar to 10(-3) per wall atom or 10(20) cm(-2). Thes e gases may modify the thermophysical properties of the wall material. (C) 1998 Elsevier Science B.V. All rights reserved.