Progress in ITER project and its superconducting magnet system in Japan

Okuno, Kiyoshi; Nakajima, Hideo; Takahashi, Yoshikazu; Koizumi, Norikiyo

ITER is a joint international project and its participants are the European Union, Japan, the People's Republic of China, India, the Republic of Korea, the Russian Federation and the USA. The ITER, will be constructed in Europe, at Cadarache in France. ITER will demonstrate high power amplification and extended burn of deuterium-tritium plasmas, in a steady state as an ultimate goal, with the technologies essential to a reactor in an integrated system. Superconducting magnets are one of these technologies, which induce an electrical current and confine and control the reacting plasma. The ITER superconducting magnet systems consist of 18 Toroidal Field (TF) coils, 6 Poloidal Field (PF) coils, a Central Solenoid (CS) coil, Correction Coils, and related structures. Maximum fields are 11.8 T in the TF coil, 13 T in the CS, and below 6 T in the PF coils. The CS and TF coils use NbSn superconductor and PF coils use NbTi conductor. Japanese contribution to the construction of the ITER superconducting magnet system is to procure 25% of TF conductors, about half of TF coil winding packs, all of TF coil structures and all of CS conductors. Total amount of raw stainless steel materials required for the TF coil structures is more than 10,000 tons. The Japanese Domestic Agency, represented by Japan Atomic Energy Agency (JAEA), has performed extensive technology development for the preparation of these procurements. These include (1) trial fabrication of the superconductors at industry level and their performance demonstration, (2) manufacturing studies and full-scale trial fabrication of TF coil including its structures, and (3) establishment of database on the structural materials.