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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
Hiroyuki Okada, Yuki Torii, Shinji Kobayashi, Masashi Kaneko, Jun Arakawa, Hiroki Kitagawa, Takashi Mutoh, Tohru Mizuuchi, Kazunobu Nagasaki, Yasuhiro Suzuki, Yuji Nakamura, Takashi Takemoto, Satoshi Yamamoto, Hajime Arimoto, Kiyoshi Hanatani, Katsumi Kondo, Fumimichi Sano
Fusion Science and Technology | Volume 50 | Number 2 | August 2006 | Pages 287-293
Technical Paper | Stellarators | doi.org/10.13182/FST06-A1248
Articles are hosted by Taylor and Francis Online.
A fast-ion formation and confinement experiment is performed using the ion cyclotron range of frequencies (ICRF) minority heating scheme in Heliotron J. In particular, the role of one of the Fourier components, the bumpiness, is an important issue for the design principle of the magnetic field of Heliotron J, where the particle confinement is controlled by the bumpiness. We study the dependence of the fast-ion confinement on the bumpiness using fast ions produced by the ICRF heating.High-energy ions are produced up to 10 keV by injecting an ICRF pulse into electron cyclotron heating target plasmas. Moreover, ions up to 36 keV are observed in the combination heating of ICRF and neutral beam injection (NBI), where the NBI energy is 28 keV. To clarify the role of the bumpy component for the high-energy ions, three configurations with various bumpy components are selected. The tail temperature is highest in the high bumpy case. It is considered that bumpy control is effective for the fast-ion confinement in Heliotron J. An increase of the bulk-ion temperature from 0.2 to 0.4 keV is observed during the ICRF pulse. The heating efficiency also depends on the bumpy component.
