Development of the superconductors for ITER magnet system

A review is given of the present status of the development and production of Nb3Sn and Nb-Ti superconductors for the Model Coils and the real Magnet System of the International Thermonuclear Experimental Reactor (ITER) in the Russian Federation Home Team. It is shown that Nb3Sn bronze processed superconductors produced for the Model Central Solenoid Coil insert meet the ITER joint Central Team requirements. In particular, the critical current density, measued in non-Cu area is not less than 550 A/mm(2) for 12 T at 4.2 K, the level of hysteresis losses is not in excess of 200 mJ/cm(3), and the Cu-stabilizing shell resistivity ratio of Cr-plated wire is 150. Internal tin Nb3Sn superconductor development and test results are presented, confirming the possibility of their application for the ITER Magnet System winding. Nb-Ti superconductors for PF coils properties have also been considered. The possibility of Nb3Sn and Nb-Ti superconductor manufacture with the use of large composite billets up to 300 mm in dia is shown, creating the possibility for large scale industrial production (several tens of tons/year) of these materials for the ITER Magnet System. (C) 1998 Elsevier Science B.V. All rights reserved.