Development of Nb3Al superconductors for International Thermonuclear Experimental Reactor (ITER)

✍ Scribed by Y. Yamada; N. Ayai; A. Mikumo; M. Ito; K. Hayashi; K. Takahashi; K. Sato; N. Koizumi; T. Ando; K. Matsui; M. Sugimoto; H. Tsuji; K. Okuno

• Publisher: Elsevier Science
• Year: 1999
• Tongue: English
• Weight: 500 KB
• Volume: 39
• Category: Article
• ISSN: 0011-2275
• DOI: 10.1016/s0011-2275(99)00022-3

✦ Synopsis

A fabrication technique of a Nb 3 Al strand using mass-production billets was developed for the framework of International Thermonuclear Experimental Reactor (ITER) Engineering Design Activity (EDA). The weight of a multifilament billet is about 70 kg, which corresponds to the total length of the wire of about 16 000 m. The critical current density is over 600 A mm -2 at 4.2 K, 12 T, and the hysteresis loss for the field parallel to the wire axis is lower than 600 mJ cm -3 at Ϯ 3 T. The residual resistivity of the chrome-plated wire is drastically improved to be lower than 1.6 ϫ 10 -10 ⍀m with setting the large copper area at the centre, which reduces the chrome diffused into the copper. The yield of the superconducting strand has been improved, resulting in a yield of 70% for wire longer than 1500 m. The total volume of fabricated Nb 3 Al superconducting strand for ITER Nb 3 Al insert coil, which is fabricated in the ITER-Central Solenoid (CS) model coil program, is about 210 000 m, i.e. 1000 kg. This is the first experience of mass-production for Nb 3 Al superconductors in the world.