Resonant nuclear reaction analysis can be used for the study of diffusion behaviour of minor alloying elements in reactor structural materials. In the present paper,15N(p,αγ)12Cand30Si(p,γ)31Preactions have been used to profile the ion-implanted15Nand30Siin D9 alloy (titanium-modified austenitic stainless steel). The diffusion coefficients at various temperatures have been estimated from the broadening of the implantation profiles during thermal annealing, and the activation energies are deduced.