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Division Spotlight
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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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.”
Yuri Igitkhanov, Gerald Kent McCormick, Peter Eckhard Grigull
Fusion Science and Technology | Volume 46 | Number 1 | July 2004 | Pages 101-105
Technical Paper | Stellarators | doi.org/10.13182/FST04-A545
Articles are hosted by Taylor and Francis Online.
A plausible physical explanation of a new advanced high-density H (HDH)-mode operational regime on the W7-AS stellarator is discussed. The HDH regime can be achieved only under a high rate of particle fueling during the starting phase of the discharge. It can be shown that at high enough fueling rates, the density profile grows at the source position, because the relatively weaker diffusivity hinders redistribution of the plasma. This leads to formation of a density gradient at the edge and brings about the radial electric field, which suppresses the plasma turbulence [the edge transport barrier (ETB) formation]. The appearance of the ETB depends on the initial condition, i.e., on the fueling rate, but a steady-state operation depends on the average density value. This critical value can be assessed from the energy and particle balance at the edge, where the transport coefficients depend on the plasma parameters in such a way that bifurcation can occur. The bifurcation occurs between two stable solutions, which are characterized by different values of the particle flux and energy confinement time, reminiscent of the normal confinement and HDH stages. The scaling analysis shows that the threshold average density required for transition increases weakly with power and inverse aspect ratio.