Procurement of NbSn superconducting conductors in ITER

Nabara, Yoshihiro; Isono, Takaaki; Nunoya, Yoshihiko; Koizumi, Norikiyo; Hamada, Kazuya; Matsui, Kunihiro; Hemmi, Tsutomu; Kawano, Katsumi; Uno, Yasuhiro*; Seki, Shuichi*; Ito, Sachito*; Oshikiri, Masayuki; Yoshikawa, Masatoshi*; Takano, Katsutoshi; Tsutsumi, Fumiaki; Takahashi, Yoshikazu; Nakajima, Hideo; Okuno, Kiyoshi

Superconducting strands are applied to Toroidal Field (TF) coil, Poroidal Field (PF) coil and Centre Solenoid (CS) in ITER. Japanese share of TF conductor is 25% and that of CS is 100%. The TF conductor contains 900 NbSn superconducting strands. As described in the length of strand, the length of Japanese share is 23000 km. In order to generate the magnetic field of which maximum value is 11.8 T, 68 kA of current is sent through the conductor under the rated operation. Although the critical current must be high, the high critical current tends to make the hysteresis loss rise at the same time. The strands which satisfy these performances compatibly had been developed. In advance of the other parties, the production of TF strands started in 2008. To date, 3400 km long strands have been fabricated. Some of them are going to be cabled soon. The jacketing facility of TF conductor is being newly built. The procurement of strands for TF coil is underway.