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Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
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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.”
Akiyosi Itakura, Naoki Goto, Masayuki Katoh, Yuichiro Kogi, Yoriko Shima, Hitoshi Hojo, Kiyoshi Yatsu, Shigeyuki Kubota, Atsushi Mase, Tsuyoshi Onuma
Fusion Science and Technology | Volume 39 | Number 1 | January 2001 | Pages 265-268
Poster Presentations | doi.org/10.13182/FST01-A11963457
Articles are hosted by Taylor and Francis Online.
Two types of microwave reflectometries are installed in the GAMMA 10 device for electron density profile and fluctuation measurement. Microwave is injected into the plasma in the O-inode or in the X-mode and is reflected at the cutoff layer where the electron plasma frequency corresponding to the electron density is equal to the frequency of incident wave.
An ultra short pulse method uses pulse train having duration of 65 ps and repetition rale of 250 kHz generated by an impulse generator. This signal has a broad frequency spectrum in microwave region. So simple transmitting system is realized. Reflected wave is divided into five frequency channels. Their center frequencies are 7, 8, 9, 10 and 11 GHz. Time of flight of each frequency component is measured using a time to amplitude converter. Location of reflected point is calculated from the time of flight. An electron density profile is reconstructed with one-shot data.
Fast frequency-modulation method is also used. The microwave source is swept from 11.5 GHz to 17.5 GHz: The signal is injected in the X-mode. Phase difference between reference wave and reflected wave is observed. Density profile is reconstructed from the phase difference data. There is low frequency fluctuation in the plasma. When sweep time is faster than 20 μ s, reliable data are obtained. This system has a rather simple receiving system.
Though reflected wave has an information of fluctuation, several methods of frequency analysis are tried and distribution of fluctuation is observed simultaneously.
Magnetic fluctuation is also observed by cross-polarization scattering method.