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2025: The year in nuclear
As Nuclear News has done since 2022, we have compiled a review of the nuclear news that filled headlines and sparked conversations in the year just completed. Departing from the chronological format of years past, we open with the most impactful news of 2025: a survey of actions and orders of the Trump administration that are reshaping nuclear research, development, deployment, and commercialization. We then highlight some of the top news in nuclear restarts, new reactor testing programs, the fuel supply chain and broader fuel cycle, and more.
Yuji Nakamura, Masahiro Wakatani, Jean-Noel Leboeuf, B. A. Carreras, N. Dominguez, Jeff A. Holmes, V. E. Lynch, S. L. Painter, Luis Garcia
Fusion Science and Technology | Volume 19 | Number 2 | March 1991 | Pages 217-233
Technical Paper | Plasma Engineering | doi.org/10.13182/FST91-A29361
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Confinement properties of l-2 torsatron/heliotron configurations with number of toroidal field periods, M, in the range of 10 to 14 are studied. This involves the calculation of zero-current and flux-conserving equilibria; stability against Mercier modes and low-n ideal modes, with n denoting the toroidal mode number; and orbit confinement of deeply trapped energetic particles. Optimization of both mag-netohydrodynamic (MHD) and transport properties is pursued under the condition of plasma aspect ratio A = R/a ≥ 7, with R denoting the major radius and a the average plasma radius. For configurations with M ≤ 12, an average MHD beta limit of 4 to 5% is possible. The addition of a quadrupole field improves the confinement of trapped particles at zero pressure, but particle losses increase with increasing beta. This loss is less severe if the vacuum magnetic axis is shifted slightly inward. A configuration with M = 10, a coil pitch parameter pc in the range 1.25 to 1.30, and an added quadrupole field satisfies the beta and energetic particle confinement requirements for the next generation of large torsatron/heliotron devices.