Defect structure evolution in early-stage neutron irradiated F82H and its model alloys at 363 K and 563K

To understand the point defect processes during the incubation period of the void swelling is critical for the development of nuclear structural materials. The defect structures in the incubation period in neutron irradiated Fe and 6 model alloys of F82H, increasing the elements from Fe, were studied by positron annihilation lifetime spectroscopy and transition electron microscopy. During the irradiation at 363 K, vacancy clusters were detected in Fe and all model alloys to a dose of 0.2 dpa. With 563 K irradiation, no vacancy clusters were detected except for Fe. These results suggest the effect of Cr on model change of the long-range migration of these interstitial-type loops at high temperature. The start of steady state swelling is the saturation of the effective number of Cr atoms interacting with Fe interstitial clusters.