Since 18 of December 2019 uses Nucleus credentials. Visit our help pages for information on how to Register and Sign-in using Nucleus.

Oct 13 – 18, 2014
Hotel Park Inn Pribaltiyskaya
Europe/Moscow timezone

Development of DC Ultra-High Voltage Insulation Technology for ITER NBI

Oct 16, 2014, 8:30 AM
Green 8-9 (Hotel Park Inn Pribaltiyskaya)

Green 8-9

Hotel Park Inn Pribaltiyskaya

Saint Petersburg, Russian Federation
Poster Poster 5


Dr Hiroyuki Tobari (Japan Atomic Energy Agency)


In the ITER NBI for plasma heating and current drive, a 1 MeV, 40 A deuterium negative ion (D-) beam is designed to be accelerated for 3600 s. The beam energy and the pulse duration of the D- beam are 2-5.5 times higher and 360 times longer than those in the negative-ion-based NBIs on LHD and JT-60U, respectively. Thus, to realize higher voltage and longer pulse duration, the generation, transmission and insulation of DC ultra-high voltage are critical issues for the ITER NBI. In addition, the high-current busbar, cooling water and gas pipes at -200 kV~ -1 MV potential are simultaneously transmitted through the HV bushing from the gas-insulated transmission line in the PS to the beam source (BS) to minimize the installation space. Those are significant differences from that in existing N-NB systems. Especially, a DC 1 MV insulating transformer for feeding an electric power from the ground to 1 MV potential is one of most challenging components. For stable power transmission through the HV bushing, 1 MV vacuum insulation and a stiffness to withstand the maximum pressure difference of 0.9 MPa in a limited space are required. Japan Atomic Energy Agency (JAEA) is in charge of the procurement of these high voltage parts of the 1 MV PS and the HV bushing. As for the insulating transformer, a DC long pulse insulation structure and a composite bushing for the isolation of the high-voltage to the air have been newly developed. The mockup transformer successfully demonstrated a stable insulation of DC -1.2 MV for 3600 s. The HV bushing serves as the terminal of the HV transmission line. It is made in five 200 kV stages and a two-stage mockup has been developed, and stable voltage holding at 480 kV for 3600 s was demonstrated. These R&D results fulfill the ITER requirement, which allows the realization of the PS and HV bushing for the ITER NBI.
Country or International Organisation Japan
Paper Number FIP/2-5Ra

Primary author

Dr Hiroyuki Tobari (Japan Atomic Energy Agency)


Mr Daisuke Shiina (Japan Atomic Energy Agency) Dr Deirdre Boilson (ITER organization) Dr Hans Decamps (ITER organization) Mr Haruhiko Yamanaka (Japan Atomic Energy Agency) Mr Hiroyuki Abe (Japan Atomic Energy Agency) Dr Joseph Graceffa (ITER organization) Dr Kazuhiro Watanabe (Japan Atomic Energy Agency) Mr Kohei Yamaguchi (Hitachi, ltd.) Dr Lennart Svennson (ITER organization) Mr Makoto Kadowaki (Hitachi, ltd.) Dr Masaaki Kuriyama (ITER organization) Mr Masaya Hanada (Japan Atomic Energy Agency) Mr Masayuki Dairaku (Japan Atomic Energy Agency) Dr Mieko Kashiwagi (Japan Atomic Energy Agency) Mr Naotaka Umeda (Japan Atomic Energy Agency) Mr Notikatsu Seki (Japan Atomic Energy Agency) Dr Ronald Hemsworth (ITER organization) Mr Shigeru Tanaka (HItachi, ltd.) Mr Tatsuo Kondo (Japan Atomic Energy Agency) Mr Tetsuya Maejima (Japan Atomic Energy Agency) Mr Yuto Terunuma (Japan Atomic Energy Agency)

Presentation materials