Structural and Phase Changes and Radiation Damage in Low-Activation Vanadium--Titanium Alloys on Electron and Neutron Irradiation

Vanadium and V--Ti alloys were irradiated either at 100 deg C with electrons (E = 2.2 MeV) or at approx 150 deg C in the SM-2 reactor. The maximum electron irradiation fluence was 5 x 10 exp 22 , and neutron fluence was equal to 4.7 x 10 exp 24 m exp --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 V--Ti alloys are discussed on the basis of the results obtained. Calculations of the induced radioactivity and its decay behaviour after shutdown in hypothetically pure V and V--Ti alloys were carried out. Studies of the radionuclides produced in V and a V-21.5 at.% Ti alloy after irradiation in the SM-2 reactor to a fluence of 5 x 10 exp 24 m exp --2 were conducted with the use of gamma spectroscopy.