Conceptual design of Japan's fusion DEMO reactor (JADEMO) and superconducting coil issues

K. Tobita, H. Utoh, R. Hiwatari, Y. Miyoshi, S. Tokunaga, Y. Sakamoto, Y. Someya, N. Asakura, Y. Homma, N. Nakajima

Research output: Contribution to journalConference articlepeer-review

12 Citations (Scopus)


Goals of Japan's fusion demonstration (DEMO) reactor are to demonstrate (1) steady and stable electric power generation in a power plant scale, (2) self-sufficient production of fuel (tritium), and (3) reasonable availability using a remote maintenance scheme anticipated in a commercial plant. Main design parameters of JA DEMO are a plasma major radius of 8.5 m, fusion output of 1.5-2 GW, magnetic field on the plasma axis of 5.94 T. The superconducting coil system of the reactor consists of a central solenoid (CS), 7 poloidal field (PF) coils and 16 toroidal field (TF) coils. Regarding CS and PF coils, superconducting coil technology on DEMO is basically the same as that on the world largest fusion experimental reactor called ITER. In contrast, TF coils have a technology gap on magnetic energy and the resulting stress between ITER and DEMO due to their size and magnetic field. In particular, the necessity of higher design stress is critical for TF coils, requiring the development of high strength cryogenic steels surpassing the existing ones. The fundamental design strategy to mitigate tolerances in TF coil fabrication is also presented.

Original languageEnglish
Article number012078
JournalJournal of Physics: Conference Series
Issue number1
Publication statusPublished - 2019 Oct 15
Event31st International Symposium on Superconductivity, ISS 2018 - Tsukuba, Ibaraki, Japan
Duration: 2018 Dec 122018 Dec 14


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