RADIATION DEFECT FORMATION AND EVOLUTION IN C0.03CR20NI16MN6 STEEL UNDER LOW-TEMPERATURE NEUTRON-IRRADIATION AND THEIR EFFECT ON PHYSICAL AND MECHANICAL-PROPERTIES OF THE STEEL

Radiation defect formation in austenitic steel under low-temperature i rradiation was analysed. Certain approximations were made to calculate the neutron interaction with a multicomponent system, such as austeni tic steel, and atomic displacements in cascade regions. These approxim ations were used to calculate a threshold energy for stable Frenkel pa ir formation. The level of gas transmutant generation by neutron irrad iation was estimated. A qualitative interpretation of the microstructu ral changes in austenite stainless steel under low-temperature neutron irradiation was formulated. The radiation defect types dominating phy sical and mechanical properties were considered. A model to describe a n influence of these defects on steel strength properties, plasticity, and thermal expansion characteristics was suggested. C0.03Cr20Ni16Mn6 steel property variation under neutron irradiation to the fluence of 1 x 10(23) n/m(2) (E greater than or equal to 0.1 MeV) at 77 K was cal culated within the mechanisms selected. The results obtained were comp ared to data on low-dose mechanical properties, Young's modulus and th e thermal linear expansion coefficient of C0.03Cr20Ni16Mn6 steel speci mens, irradiated to the fluence 1 x 10(22) n/m(2), 5 x 10(22) n/m(2), and 1 x 10(23)n/m(2) at 77 K and tested at the same temperature as wel l as after heating to room temperature.