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Division Spotlight
Human Factors, Instrumentation & Controls
Improving task performance, system reliability, system and personnel safety, efficiency, and effectiveness are the division's main objectives. Its major areas of interest include task design, procedures, training, instrument and control layout and placement, stress control, anthropometrics, psychological input, and motivation.
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Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
Standards Program
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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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.”
Christopher S. Handwerk, Michael J. Driscoll, Pavel Hejzlar
Nuclear Technology | Volume 164 | Number 3 | December 2008 | Pages 320-336
Technical Paper | Fission Reactors | doi.org/10.13182/NT08-A4030
Articles are hosted by Taylor and Francis Online.
The gas-cooled fast reactor (GFR) has received increased attention in the past decade under the impetus provided by the Generation-IV International Forum. The GFR given principal attention is a version using helium as a coolant. However, the work presented here is for a core using supercritical carbon dioxide (S-CO2) as a coolant, in a direct Brayton cycle, which has comparable cycle efficiency (~45%) at much lower temperatures (e.g., 650°C versus 850°C) than helium-based cycles.A reactor core for use in this direct cycle S-CO2 GFR has been designed that satisfies established neutronic and thermal-hydraulic steady-state design criteria, while concurrently supporting the Gen-IV criteria of sustainability, safety, proliferation, and economics. Use of innovative tube-in-duct fuel has been central to accomplishing this objective, as it provides a higher fuel volume fraction and lower fuel temperatures and pressure drop when compared to traditional pin-type fuel. Further, this large fuel volume fraction allows for a large enough heavy metal loading for a sustainable core lifetime without the need for external blankets, enhancing the proliferation resistance of such an approach. It was not possible to achieve a sustainable core (i.e., conversion ratio = 1.0) using conventional pin-type oxide fuel.Use of beryllium oxide (BeO) as a diluent is explored as a means for both power shaping and coolant void reactivity (CVR) reduction, similar to the studies carried out earlier for the sodium-cooled European Fast Reactor. Results show that relatively flat power profiles can be maintained throughout a batch-loaded "battery" core life of more than 15 yr using a combination of fissile concentration and diluent zoning, due to the moderating effect of the BeO. Combining BeO diluent with the innovative strategy of using a thick volume of S-CO2 coolant in the radial reflector yields negative CVR values throughout core life, a rare, if not unique accomplishment for fast reactors. The ability to maintain negative CVR comes from a combination of the effects of spectral softening due to the BeO diluent and the enhanced leakage upon voiding of the S-CO2 radial reflector.