Migration kinetic of primary radiation defects at nonuniform irradiation

The migration of interstitial atoms and vacancies under nonuniform irradiation is theoretically studied. The possibility of the formation of regions with increased concentration of point defects of certain kind in crystalls with low concentration of dislocatios at the surface and at Bragg peak is demonstrated. The region of the penetration of interstitials beyond the irradiated area is estimated. It might be of order of 0.02 sm at the dislocation density 104 cm-2. The difference of the flows of interstitials and vacancies changes its sign in process of irradiation which can lead to different processes of macroscopic defect formation at the imitial stages of irradiation and in the stationary state.