The influence of low-temperature neutron irradiation on physicomechanical properties of new reactor alloys saturated with tritium

The influence of tritium (∼0.03 at.%) and low-temperature (77 K) neutron irradiation (fluence 1.5×1018–15×1018 n cm−2) on changes in physical and mechanical properties of stainless steels at 77 K was studied. Strength of the steels was found to be considerably enhanced by increasing the fluence of fast neutrons (power dependence). This increase in strength is explained by the appearance of a large number of clusters formed at low temperatures (hence termed ‘low-temperature clusters’) under cascade-forming irradiation. The deterioration of plasticity of BCC steels and alloys was shown to be an order of magnitude faster than that for reactor materials having an FCC lattice.