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Division Spotlight
Nuclear Installations Safety
Devoted specifically to the safety of nuclear installations and the health and safety of the public, this division seeks a better understanding of the role of safety in the design, construction and operation of nuclear installation facilities. The division also promotes engineering and scientific technology advancement associated with the safety of such facilities.
Meeting Spotlight
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.”
Jiyun Zhao, Pradip Saha, Mujid S. Kazimi
Nuclear Technology | Volume 161 | Number 2 | February 2008 | Pages 108-123
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT08-A3917
Articles are hosted by Taylor and Francis Online.
Using a three-region supercritical water flow model, the core-wide in-phase stability of the U.S. reference supercritical water-cooled reactor (SCWR) design is investigated. The reactor core is simulated as three channels according to the radial power distribution. A method based on modes (reactivity modes) expansion of neutronic kinetic equations is applied. A constant pressure drop boundary condition between the feedwater pump and the turbine control valve is assumed. Cases with and without water rods heating are studied.It is found that the stability of the U.S. reference SCWR design is sensitive to the flow restrictions in the hot fluid or the steam line. As long as the restriction in the steam line is small, the design will be stable. A pressure loss coefficient of 0.25 is assumed for the exit valve on the steam line in this analysis. With this value, the SCWR is stable with a large margin. It is concluded that the presence of water rods heating will reduce the stability margin and increase the flow rate sensitivity while maintaining the power sensitivity level.The decay ratios for the three density wave oscillation modes, i.e., single hot channel, coupled neutronic out-of-phase and in-phase, are compared at steady-state conditions. It is found that the single hot channel oscillation mode is the most limiting one in the absence of the water rods heating, while the in-phase oscillation mode is most limiting in the presence of water rods heating.