Prospects and problems using vanadium alloys as a structural material of the first wall and blanket of fusion reactors

Vanadium-based alloys are most promising as low activation structural materials for DEMO. It was previously established that high priority is to be given to V-alloys of the VTiCr system as structural materials of a tritium breeding blanket and the first wall of a fusion reactor. However, there is some uncertainty in selecting a specific element ratio between the alloy components in this system. This is primarily explained by the fact that the properties of V-alloys are dictated not only by the ratio between the main alloying elements (here Ti and Cr), but also by impurities, both metallic and oxygen interstitials. Based on a number of papers today one can say that VTiCr alloys with insignificant variations in the contents of the main constituents within 5–10 mass% Ti and 4–6 mass% Cr must be taken as a base for subsequent optimization of chemical composition and thermomechanical working. However, the database is obviously insufficient to assess the ecological acceptability (activation), physical and mechanical properties, corrosion and irradiation resistance and, particularly, the commercial production of alloys. Therefore, there is a need for comprehensive studies of promising V-alloys, namely V4Ti4Cr and V10Ti5Cr.