Abstract: A neutron transport code and a charged-ion radiation damage code have been linked to simulate neutron induced defects in the static, multi-component amorphous target. In simulating collision cascades, replacement collisions have been taken into account, especially. It corrected the value of DPA about 10%~20%. Improper replacements were recorded also. The radiation damage in two kinds of materials candidated for the first wall in fusion reactor is calculated. Calculation gives the production rates of PKA and DPA, gas production rates and their depth distributions. The results show that damage distributions are almost uniform body distributions, the DPA value of PE-16 is a little larger than that of SS316, the hydrogen production rates is nearly two times as much as that of SS316, the helium production rates is 1.45 times as much as that of SS316. It means that the radiation damage of PE-16 is more serious than that of SS316. The cross section data from MC(87) n library is used in the calculation.

Key words: radiation damage, primary knock-on atom, displacement per atom, helium and hydrogen production rates, replacement collision, improper replacement