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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.
J. Miyazawa, S. Masuzaki, R. Sakamoto, B. J. Peterson, N. Tamura, M. Goto, M. Kobayashi, M. Shoji, T. Akiyama, H. Yamada, LHD Experiment Group
Fusion Science and Technology | Volume 58 | Number 1 | July-August 2010 | Pages 200-207
Chapter 5. Divertor and Edge Physics | Special Issue on Large Helical Device (LHD) | doi.org/10.13182/FST10-A10807
Articles are hosted by Taylor and Francis Online.
Easy access to the high-density regime without fatal disruptive phenomena is one of the important characteristics of the Large Helical Device (LHD). The operational density is considerably higher than the Greenwald density limit for tokamak plasmas. The density limit in LHD is reached when the edge density at the last closed flux surface exceeds a value approximately equivalent to the Sudo density limit that increases with the square root of the heating power. Extremely high central density of >1 × 1021 m-3 is achievable with a peaked density profile, as long as the edge density is kept lower than the Sudo limit. Furthermore, the central heating power must be larger than the radiation loss in the core region to avoid the "cold-core" phenomenon. As for the plasma edge, complete detachment takes place when the edge density exceeds the limit. Then, reattachment/Serpens mode/radiative collapse will follow, depending on the recycling condition.