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Fusion Science and Technology
Latest News
Vogtle-3 shuts down for valve issue
One of the new Vogtle units in Georgia was shut down unexpectedly on Monday last week for a valve issue that has since been investigated and repaired. According to multiple local news outlets, Georgia Power reported on July 17 that Unit 3 was back in service.
Southern Company spokesperson Jacob Hawkins confirmed that Vogtle-3 went off line at 9:25 p.m. local time on July 8 “due to lowering water levels in the steam generators caused by a valve issue on one of the three main feedwater pumps.”
R. J. Groebner, T. H. Osborne, M. E. Fenstermacher, A. W. Leonard, M. A. Mahdavi, R. A. Moyer, L. W. Owen, G. D. Porter, P. B. Snyder, P. C. Stangeby, T. L. Rhodes, N. S. Wolf
Fusion Science and Technology | Volume 48 | Number 2 | October 2005 | Pages 1011-1020
Technical Paper | DIII-D Tokamak - Achieving Reactor Quality Plasma Confinement | doi.org/10.13182/FST05-A1056
Articles are hosted by Taylor and Francis Online.
Studies of the H-mode pedestal in the DIII-D tokamak are presented. The global energy confinement increases as the plasma pressure on top of the pedestal increases. The best empirical description for a pedestal width parameter is pe [proportional to] (polPED)0.4, where pe is the width of the electron pressure pedestal and polPED is the poloidal beta at the top of the pedestal. The edge profiles of electron density ne, electron temperature Te, and ion temperature Ti can all have different shapes. Thus, a simple width scaling for the edge might not exist, and studies of the physics of individual profiles have been initiated. A model for the ne profile, based on self-consistent treatment of edge particle sources and edge particle transport, agrees with several experimental observations. The steep gradient region for the Te profile often extends farther into the plasma than the ne pedestal step. Magnetohydrodynamic stability provides the ultimate limits to the evolution of the pedestal and usually leads to edge instabilities called edge-localized modes (ELMs). However, the absence of ELMs in a regime called the Quiescent H-mode shows that large pedestals can be produced without ELMs.