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Smarter waste strategies: Helping deliver on the promise of advanced nuclear
At COP28, held in Dubai in 2023, a clear consensus emerged: Nuclear energy must be a cornerstone of the global clean energy transition. With electricity demand projected to soar as we decarbonize not just power but also industry, transport, and heat, the case for new nuclear is compelling. More than 20 countries committed to tripling global nuclear capacity by 2050. In the United States alone, the Department of Energy forecasts that the country’s current nuclear capacity could more than triple, adding 200 GW of new nuclear to the existing 95 GW by mid-century.
Masami Fujiwara, Nobuyoshi Ohyabu, Keisuke Matsuoka, Shoichi Okamura, Osamu Motojima, Tokuhiro Obiki, Fumimichi Sano, Katsumi Kondo, Masahiro Wakatani, Tohru Mizuuchi, Kiyoshi Hanatani, Yuji Nakamura, Kazunobu Nagasaki, Hiroyuki Okada, Sakae Besshou, Masahiko Nakasuga
Fusion Science and Technology | Volume 42 | Number 1 | July 2002 | Pages 32-49
Technical Paper | doi.org/10.13182/FST02-A211
Articles are hosted by Taylor and Francis Online.
Experimental results are summarized for major helical devices in Japan: Large Helical Device (LHD), Compact Helical System (CHS), and Heliotron J. The LHD and CHS have planar magnetic axes, while Heliotron J has a nonplanar magnetic axis.The LHD, the largest superconducting device in the world, has the following machine parameters: major radius R of 3.9 m, average minor radius a of 0.6 m, magnetic field on axis B of 3 T, multipolarity l of 2, toroidal period number m of 10, and auxiliary heating power P of ~14 MW. The LHD achieved the maximum stored energy Wp dia of > 1 MJ, the maximum value of the volume averaged beta <dia*gt; of >3.0% at B of 0.5 T, high confinement time E of 0.3 s at Te(0) of 1.1 keV and <ne> of 6.5 × 1019 m-3, and long pulse operations up to 120 s at high temperature.The CHS has the following machine parameters: R = 1 m, a = 0.2 m, l = 2, and m = 8. The parameters of neutral beam heated plasmas are in the range with <ne> of ~4 to 5 × 1019 m-3, Te(0) of 500 to 700 eV, and energy confinement time of several milliseconds. Progress has been made in studies of bifurcation phenomena of electric potential, neoclassical internal transport barriers, and plasma flows in the toroidal and poloidal directions.The most important achievement from recent CHS and LHD experiments is to realize the internal transport barriers on the basis of potential bifurcation.Heliotron J, which was converted from the Heliotron E (H-E) device, employs a helical magnetic axis by the use of l = 1 continuous helical coil and auxiliary coils such as poloidal and toroidal coils. The machine parameters are as follows: R = 1.2 m, a = 0.1 to 0.2 m, and B = 1 to 1.5 T. Initial results show the maximum stored energy Wp ~ 0.7 kJ and <> ~ 0.2%.The range of plasma parameters has been greatly expanded by the LHD, CHS, H-E, and Heliotron J experiments. The confinement data in helical devices are scaled empirically as ISS-95 (International Stellarator Scaling), and plasma performance is comparable with that in tokamaks.
