Electromechanical properties of superconductors for DOE fusion applications

Abstract

The electrical performance of many superconducting materials is strongly dependent on mechanical load. This report presents electromechanical data on a broad range of high-magnetic-field superconductors. The conductors that were studied fall into three general categories: Candidate conductors, experimental conductors, and reference conductors. Research on candidate conductors for fusion applications provides screening data for superconductor selection as well as engineering data for magnet design and performance analysis. The effect of axial tensile strain on critical-current density was measured for several Nb{sub 3}Sn candidate conductors including the US-DPC (United States Demonstration Poloidal Coil) cable strand and an ITER (International Thermonuclear Experimental Reactor) candidate conductor. Also, data are presented on promising experimental superconductors that have strong potential for fusion applications. Axial strain measurements were made on a V{sub 3}Ga tape conductor that has good performance at magnetic fields up to 20 T. Axial strain data are also presented for three experimental Nb{sub 3}Sn conductors that contain dispersion hardened copper reinforcement for increased tensile strength. Finally, electromechanical characteristics were measured for three different Nb{sub 3}Sn reference conductors from the first and second VAMAS (Versailles Project on Advanced Materials and Standards) international Nb{sub 3}Sn critical-current round robins. Published papers containing key results, including the first measurement of the transverse stress effect in Nb{sub 3}Sn, the effect of stress concentration at cable-strand crossovers, and electromechanical characteristics of Nb{sub 3}Al, are included throughout the report. Selected papers were indexed separately for inclusion in the Energy Science and Technology Database.