Edge effects caused by enhancement of DD/DT fusion reactions in metals at low energy of projectile particles in an ITER-type fusion reactor

Experimental data on enhancement of the yield of DD/DT reactions in metal targets at low energies of projectile deuterons (E d < 5 keV) were analyzed. A semiempirical expression was obtained to describe the dependence of the screening energy for deuterons upon the effective number of mobile deuterium atoms on the target metal surface. Numerical estimates showed that the edge plasma effects in ITER-type fusion reactors can be an additional source of generation of α-particles and of the buildup of 4He atoms in first-wall and divertor materials.