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Division Spotlight
Operations & Power
Members focus on the dissemination of knowledge and information in the area of power reactors with particular application to the production of electric power and process heat. The division sponsors meetings on the coverage of applied nuclear science and engineering as related to power plants, non-power reactors, and other nuclear facilities. It encourages and assists with the dissemination of knowledge pertinent to the safe and efficient operation of nuclear facilities through professional staff development, information exchange, and supporting the generation of viable solutions to current issues.
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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August 2024
Nuclear Technology
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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.”
A. K. Kuczaj, E. M. J. Komen
Nuclear Technology | Volume 170 | Number 1 | April 2010 | Pages 2-15
Technical Paper | Special Issue on the 2008 International Congress on Advances in Nuclear Power Plants / Thermal Hydraulics | doi.org/10.13182/NT10-A9441
Articles are hosted by Taylor and Francis Online.
A potential cause of thermal fatigue failures in energy cooling systems is identified with cyclic stresses imposed on a piping system. These are generated from temperature changes in regions where a cold flow is intensively mixed with a hot flow. Typical locations of such thermal mixing are T-junctions in nuclear reactor cooling systems. Turbulent mixing in a T-junction is investigated here using large-eddy simulation (LES). In general, LES can capture very well the mixing phenomena and the accompanying turbulent flow fluctuations that occur in a T-junction. Through a direct comparison with experimental results, an assessment of the accuracy of LES predictions is made for the Smagorinsky and the Vreman models. It is shown that the results obtained with the Vreman model are closest to the experimental results. The Smagorinsky model is found to provide the least accurate results. This is particularly detected in the near-wall regions that are of great importance in thermal fatigue predictions. Detailed numerical validation was performed with simulations using five different spatial mesh resolutions. These simulations show that computational meshes must resolve important turbulence length scales in order to obtain sufficiently accurate results. This accuracy assessment and error quantification are based on the integral and Taylor length scales of turbulence. For the investigated cases, the mesh resolution with average cell sizes of the order of /3 (three times smaller than the Taylor microscale length) is sufficient to give very similar results to those obtained on much finer meshes. An engineering estimation of the minimal mesh resolution gives an initial guideline for construction of computational meshes that allow for accurate predictions of turbulent mixing in a T-junction using LES. Additionally, analysis of the temperature measurement data at specified probe locations is presented along with a quantification of an error introduced by the applied LES method.