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Radiation Protection & Shielding
The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
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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.”
Paul B. Parks, Marshall N. Rosenbluth, Sergei V. Putvinski, Todd E. Evans
Fusion Science and Technology | Volume 35 | Number 3 | May 1999 | Pages 267-279
Technical Paper | doi.org/10.13182/FST99-A80
Articles are hosted by Taylor and Francis Online.
Proposed is a new concept for disruption mitigation and fast shutdown in tokamaks: the injection of hydrogen or helium liquid jets. Liquid jets can rapidly cool the plasma to reduce divertor heat loads and large halo current forces while simultaneously raising the density sufficiently to prevent runaway electron generation. Massive ~40- to 100-fold density increases equivalent to ~50 g of deuterium are necessary for this purpose in the International Thermonuclear Experimental Reactor (ITER). It is shown that only two or three simultaneously injected high-velocity (800 to 1200 m/s) jets can easily deliver this amount of fuel within a period of ~20 ms and thus avoid runaway electron buildup during the 50- to 500-ms current quench phase. Optimum jet parameters, such as radius, velocity, driving pressure, and injection time, predicted from a jet ablation/penetration model, lead to an innovative pulsed injector design concept. The design concept is also based on a thermodynamic process path that allows the lowest possible temperature at the nozzle orifice, given the constraint of a high, ~700-atm driving pressure. By having a cold jet exit the nozzle orifice, the potential problem of rapid boiling (flashover) during jet propagation across vacuum space between the nozzle orifice and the tokamak plasma can be overcome. A one-dimensional fluid-dynamic calculation, including finite compressibility, shows that a specially designed liquid Laval nozzle is needed for liquid helium injection because the jet velocity is supersonic (Mach number ~4). This injector concept is being considered for a proposed disruption mitigation experiment on DIII-D.