Study of radiation damage in nuclear materials by positron lifetime spectroscopy

Microstructure of four different oxide-dispersion-strengthened (ODS) steels (KAERI-A, B, C, D) with 12{\%} chromium content was studied in term of vacancy defects presence and their accumulation due to irradiation. Radiation damage was simulated by implantation of $^{2+}$He ions via a linear accelerator at the Laboratory of ion beams of the Slovak University of Technology. A second set of samples was irradiated by neutrons in Washington State University Nuclear Radiation Center. A comparison of simulated damage by $^{2+}$He and damage dealt by real reactor environment was evaluated by positron lifetime measurements in emphasis on defect accumulation.