Formation and evolution of radiation defects under low-temperature neutron irradiation

In the study of processes occurring in materials under neutron irradiation, temperature, the rate of radiation damage and the damaging dose are usually used as characteristics of its impact. However, mentioned characteristics are not enough for description of the microstructure evolution since it depends both on the amount of developed point defects and their mutual orientation. Consequently, current study proposes the way of consistent description for the processes of radiation defects formation and evolution in condition of low-temperature neutron irradiation. The feature of the way is the use of a statistic model of defect migration. For the cross section descriptions of the interactions between neutrons (depending on their energies) and atoms the analytic expressions fitting procedure is performed allowing calculations without expensive high-velocity electronic computing systems. Mentioned approach was applied to describe the radiation defects evolution in chromium (as BCC structure pattern) exposed to low-temperature neutron irradiation in the reactor IVV-2M. It is shown that calculation results have a good match with experimental data regarding the number of vacancies accumulated in the sample during irradiation obtained using the dilatometer measurements. The developed approach is supposed to be uniform due to application for the description of defects formation and evolution in pure metals as well as in the alloys under irradiation in a wider temperature range in the reactors with various neutron spectra.