Journal of Fusion Energy

, Volume 38, Issue 1, pp 138–146 | Cite as

Review of Strategy Toward DEMO in Japan and Required Innovations

  • Kunihiko OkanoEmail author
Original Research


A path and strategy toward demonstration plant (DEMO) to achieve net electric power generation and to establish various technologies for successive commercial plants will be shown based on the Japan’s action plan for fusion energy development. It is clear that the fusion power plants may not be realized without a lot of technological innovations. Required innovations to attain the commercial plant as a final target of the DEMO plant are considered and variety of novel innovations introduced in previous reactor designs in Japan have been reviewed in order to prove a possible path to the fusion power plants.


Demonstration Reactor design Strategy Roadmap Commercial fusion reactor 



The author would like to express his gratitude to Dr. Kenji Tobita of the National Institute for Quantum and Radiological Science and Technology for a lot of fruitful information on the latest DEMO design. The author also acknowledges the members of the Fusion Science and Technology Committee of the MEXT (the Ministry of Education, Culture, Sports, Science and Technology in Japan) and the Task-force for development strategy of Tokamak DEMO Reactors established under the above committee, because of their effort to work up the Action Plan for fusion energy development.


  1. 1.
    Japan’s Policy to promote R&D for a fusion DEMO reactor,
  2. 2.
  3. 3.
  4. 4.
  5. 5.
  6. 6.
    “Report by the Joint-Core Team for the Establishment of Technology Bases Required for the Development of a Fusion DEMO Fusion Reactor-Basic Concept of DEMO and Structure of Technological Issues-”, Joint core team, Feb 2015, available as NIFS-MEMO-71, (in English)Google Scholar
  7. 7.
    ibid., -Chart of Establishment of Technology Bases for DEMO-”, Joint core team, March 2015, available as NIFS-MEMO-73, (in English)Google Scholar
  8. 8.
  9. 9.
    K. Okano, R. Kasada, Y. Ikebe, Y. Ishii, K. Oba, M. Kashiwagi, R. Sakamoto, N. Sawa, H. Takenaga, A. Nishimura, M. Fukuie, S. Fujioka, Y. Ueda, T. Akiyama, An action plan of Japan toward development of demo reactor. Fusion Eng. Des. (2018). Google Scholar
  10. 10.
    K. Tobita, N. Asakura, R. Hiwatari, Y. Someya, H. Utoh, K. Katayama, A. Nishimura, Y. Sakamoto, Y. Homma, H. Kubo, Y. Miyoshi, M. Nakamura, S. Tokunaga, A. Aoki, Joint Special Team for Fusion DEMO, Design strategy and recent design activity on Japan’s DEMO. Fusion Sci. Technol. 72, 537–545 (2017)CrossRefGoogle Scholar
  11. 11.
    G. Federici, W. Biel, M.R. Gilbert, R. Kemp, N. Taylor, R. Wenninger, European DEMO design strategy and consequences for materials. Nucl. Fusion 57, 092002 (2017)ADSCrossRefGoogle Scholar
  12. 12.
    K. Hoshino, N. Asakura, S. Tokunaga, K. Shimizu, Y. Homma, Y. Someya, H. Utoh, Y. Sakamoto, K. Tobita, The Joint Special Team for Fusion DEMO, Progress of divertor study on DEMO design. Plasma Fusion Res. 12, 1405023 (2017)ADSCrossRefGoogle Scholar
  13. 13.
    N. Asakura, K. Hoshino, S. Suzuki, S. Tokunaga, Y. Someya, H. Utoh, K. Kudo, Y. Sakamoto, R. Hiwatari, K. Tobita, K. Shimizu, K. Ezato, Y. Seki, N. Ohno, Y. Ueda, Joint Special Team for DEMO Design, Studies of power exhaust and diertor design for a 1.5 GW-level fusion power DEMO. Nucl. Fusion 57, 126050 (2017)ADSCrossRefGoogle Scholar
  14. 14.
    Y. Homma, K. Hoshino, S. Yamoto, N. Asakura, S. Tokunaga, A. Hatayama, Y. Sakamoto, R. Hiwatari, K. Tobita, Joint Special Team for Fusion DEMO, Numerical analysis of tungsten erosion and deposition processes under a DEMO divertor plasma. Nucl. Mater. Energy 12, 323–328 (2017)CrossRefGoogle Scholar
  15. 15.
    Y. Someya et al., Design study of blanket structure based on a water-cooled solid breeder for DEMO. Fusion Eng. Des. 98–99, 1872 (2015)CrossRefGoogle Scholar
  16. 16.
    H. Tanigawa, H. Gwon, T. Hirose, Y. Kawamura, M. Ejiri, K. Watanabe, S. Asano, T. Kokami, Y. Oda, Cylindrical breeding blankets for fusion reactors, in Proceedings of the 13th International Symposium of Fusion Nuclear Technology (ISFNT-13), P2-061, Kyoto (2017)Google Scholar
  17. 17.
    S. Konishi, Y. Asaoka, R. Hiwatari, K. Okano, J. Plasma Fusion Res. 76, 1309–1312 (2000)Google Scholar
  18. 18.
    Y. Asaoka, S. Konishi, S. Nishio, R. Hiwatari, K. Okano, T. Yoshida, Commissioning of a DT Fusion Reactor without External Supply of Tritium, PDP-8, 18th IAEA Fusion Energy Conference, Sorrento, Italy (2000)Google Scholar
  19. 19.
    Y. Someya, H. Utoh, R. Hiwatari, H. Tanigawa, K. Tobita, Joint Special Team for Fusion, Shutdown dose-rate assessment during the replacement of in-vessel components for a fusion DEMO reactor. Fusion Eng. Des. 124, 615–618 (2017)CrossRefGoogle Scholar
  20. 20.
    H. Utoh, R. Hiwatari, K. Tobita, Y. Someya, A. Aoki, Y. Sakamoto, N. Asakura, Joint Special Team for Fusion DEMO, Technological assessment between vertical and horizontal remote maintenance schemes for DEMO reactor”. Fusion Eng. Des. 124, 596–599 (2017)CrossRefGoogle Scholar
  21. 21.
    M. Kikuchi, Steady state tokamak reactor based on the bootstrap current. Nucl. Fusion 30, 265 (1990)CrossRefGoogle Scholar
  22. 22.
    N. Inoue, Y. Ogawa, T. Yamamoto, Z. Yoshida, K. Okano, A. Hatayama, Feasibility Study for an Inductively Operated Day-long Tokamak Reactor, in Proceedings of 14th IAEA Conference on Controlled Fusion and Plasma Physics Research, vol. 3, pp. 347–353 (1993)Google Scholar
  23. 23.
    K. Okano, Y. Asaoka, T. Yoshida, M. Furuya, K. Tomabechi, Y. Ogawa et al., Compact reversed shear tokamak reactor with a superheated steam cycle. Nucl. Fusion 40, 635 (2000)ADSCrossRefGoogle Scholar
  24. 24.
    Kunihiko Okano, Neo-classical formula for neutral beam current drive. Nucl. Fusion 30, 423–430 (1990)CrossRefGoogle Scholar
  25. 25.
    K. Okano, Y. Asaoka, R. Hiwatari, T. Yoshida, Efficient hydrogen production using heat in neutron shield of fusion reactor. Plasma Sci. Nucl. Fusion Res. 77, 601–608 (2001). (in Japanese) Google Scholar
  26. 26.
    R. Hiwatari, K. Okano, Y. Asaoka, K. Shinya, Y. Ogawa et al., Demonstration tokamak fusion power plant for early realization of net electric power generation. Nucl. Fusion 45, 96–109 (2005)ADSCrossRefGoogle Scholar
  27. 27.
    S. Nishio, K. Tobita, S. Konishi, et al., Tight Aspect ratio Tokamak Power Reactor with Superconduction TF Coils, in 19th IAEA Fusion Energy Conference, Lyon, IAEA-CN-FT/P1-21 (2002)Google Scholar
  28. 28.
    S. Nishio, K. Tobita, K. Tokimatsu, K. Shinya, I. Senda, et al., Technological and environmental prospects of low aspect ratio tokamak reactor VECTOR, in 20th IAEA Fusion Energy Conference, Vilamoura, IAEA-CN-FT/P7-35 (2004)Google Scholar
  29. 29.
    K. Tobita, S. Nishio, M. Sato, S. Sakurai, T. Hayashi et al., SlimCS—Compact low aspect ratio DEMO reactor with reduced-size central solenoid. Nucl. Fusion 47, 829–899 (2007)CrossRefGoogle Scholar

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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Keio UniversityYokohamaJapan

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