Structural and phase changes and radiation damage in low-activation vanadium-titanium alloys on electron and neutron irradiation

Abstract

Vanadium and vanadium-titanium alloys were irradiated either at 100°C with electrons ( E = 2.2 MeV) or at ≈150°C in the SM-2 reactor. The maximum electron irradiation fluence was 5×10 22 m −2, and neutron fluence was equal to 4.7×10 24 m −2 ( E>0.1 MeV). The structural and phase changes in the irradiated materials were studied by utilization of positron annihilation, microhardness, and transmission electron microscopy techniques. The mechanisms of suppression of radiation damage in vanadium-titanium alloys are discussed on the basis of the results obtained. Calculations of the induced radioactivity and its decay behaviour after shutdown in hypothetically pure vanadium and vanadium-titanium alloys were carried out. Studies of the radionuclides produced in vanadium and a V-21.5at%Ti alloy after irradiation in the SM-2 reactor to a fluence of 5×10 24 m −2 were conducted with the use of gamma-spectroscopy.