PROSPECTS AND PROBLEMS USING VANADIUM ALLOYS AS A STRUCTURAL MATERIALOF 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 i s to be given to V-alloys of the V-Ti-Cr system as structural material s of a tritium breeding blanket and the first wall of a fusion reactor . However, there is some uncertainty in selecting a specific element r atio between the alloy components in this system, This is primarily ex plained by the fact that the properties of V-alloys are dictated not o nly 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 insig nificant 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 op timization of chemical composition and thermomechanical working. Howev er, the database is obviously insufficient to assess the ecological ac ceptability (activation), physical and mechanical properties, corrosio n and irradiation resistance and, particularly, the commercial product ion of alloys. Therefore, there is a need for comprehensive studies of promising V-alloys, namely V-4Ti-4Cr and V-10Ti-SCr.