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Fusion Science and Technology
China on course to lead in nuclear by 2030, says IEA
China will have the world's largest nuclear power fleet within a decade, an International Energy Agency official noted during a session at the High-Level Workshop on Nuclear Power in Clean Energy Transitions, World Nuclear News reported on March 3.
The workshop was held jointly by the IEA and the International Atomic Energy Agency.
The IEA official, Brent Wanner, head of Power Sector Modelling & Analysis for the agency's World Energy Outlook publication, said that as nuclear fleets in the United States, Canada, and Japan reach their original design lifetimes, decisions will have to be made about what will happen after that. Absent license renewals, the contribution of nuclear power could decline substantially in those countries while China’s reactor building program will boost it into the first position.
M. Greenwald, N. Basse, P. Bonoli, R. Bravenec, E. Edlund, D. Ernst, C. Fiore, R. Granetz, A. Hubbard, J. Hughes, I. Hutchinson, J. Irby, B. LaBombard, L. Lin, Y. Lin, B. Lipschultz, E. Marmar, D. Mikkelsen, D. Mossessian, P. Phillips, M. Porkolab, J. Rice, W. Rowan, S. Scott, J. Snipes, J. Terry, S. Wolfe, S. Wukitch, K. Zhurovich
Fusion Science and Technology | Volume 51 | Number 3 | April 2007 | Pages 266-287
Technical Paper | Alcator C-Mod Tokamak | dx.doi.org/10.13182/FST07-A1422
Articles are hosted by Taylor and Francis Online.
Global and local transport experiments in ohmic, L-mode and H-mode regimes on the Alcator C-Mod tokamak are summarized. For ohmic plasmas, earlier results derived for energy confinement scaling in the Alcator (linear) regime have been confirmed, and the saturated confinement regime has been shown to be equivalent to that of L-mode. For auxiliary heated regimes, C-Mod provided a unique laboratory to test the standard scaling laws that had been previously derived. C-Mod's L-mode performance matches the L-mode scaling laws quite well, but the confinement times in H-mode were about 50% above the existing H-mode scaling laws. This difference was significant and pointed up shortcomings in the range and conditioning of the existing database. H-mode studies emphasize quasi-steady regimes with good energy confinement, no impurity accumulation, and no large edge-localized modes. A new H-mode regime, where the pedestal is regulated by a continuous quasi-coherent mode, has been investigated extensively. The regime is most accessible at higher safety factor, triangularity, and collisionality and at low ion mass, suggesting that the mode is a form of resistive ballooning. Studies on C-Mod first showed the quantitative link between edge temperatures, core temperature gradients, and core confinement. This link unified L-mode and H-mode and established a strong connection between local and global transport. Further work on the role of critical gradient lengths and marginal stability lent quantitative support to the ion temperature gradient theories for ion transport and have helped elucidate nonlinear saturation mechanisms for the turbulence. Local transport studies demonstrated connections between transport channels, with energy, particle, and momentum transport varying across regimes in similar ways. Experiments carried out in collaboration with the DIII-D, ASDEX-U, and JET groups confirmed the dimensionless scaling approach over the widest available range in machine sizes. These studies suggest that plasma physics is the dominant influence on transport in the core and pedestal for standard L- and H-mode discharges. Dimensionless scaling experiments have shown a strong improvement in confinement with the normalized gyro size (1/*). Confinement was found to be Bohm-like in L-mode and gyro-Bohm-like in H-mode. These experiments also showed a strong degradation in confinement with collisionality.