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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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Nuclear Science and Engineering
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.”
Stephen M. Bajorek, Michael Y. Young
Nuclear Technology | Volume 132 | Number 3 | December 2000 | Pages 375-388
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT00-A3151
Articles are hosted by Taylor and Francis Online.
During the blowdown phase of a large-break loss-of-coolant accident (LOCA), high-powered regions of a nuclear reactor core exceed the critical heat flux, and peak-cladding temperatures (PCTs) in the range from 1033 to 1255°C (1400 to 1800°F) can occur before high flow rates terminate the temperature rise. Following the blowdown PCT, the core is cooled by a dispersed droplet flow at moderately high pressures. Heat transfer during this blowdown cooling period removes a significant portion of stored energy from the core and can lead to quench. Energy removal during this period is an important feature in the AP600 advanced passive plant design because the design includes good communication between the core and water in the reactor vessel upper head.For realistic LOCA calculations performed according to the revised 10 CFR 50.46 regulation using the code scaling, applicability, and uncertainty methodology, it becomes necessary to quantify those physical processes that have a dominant effect on the transient. Blowdown cooling heat transfer determines the initial condition of the core at the start of reflood and thus is a major contributor to the propagation of uncertainty in later periods of the transient.The approved Westinghouse best-estimate LOCA methodology uses the WCOBRA/TRAC-MOD7A code to predict the large-break LOCA transient. Quantification of blowdown cooling heat transfer coefficients (HTCs) was performed by development of a driver-plotter routine based on the WCOBRA/TRAC heat transfer package. Known fluid conditions corresponding to experimental data were then used to generate predictions of blowdown cooling HTCs. A distribution, developed from comparisons to several experimental tests, of predicted versus measured HTCs shows the average bias and uncertainty in the heat transfer package.Based on driver-plotter routine calculations of blowdown HTCs measured in the Oak Ridge National Laboratory blowdown tests and Idaho National Engineering Laboratory high-pressure single-tube tests, a new correlation for direct-contact heat transfer is proposed. Use of the new model was found to provide significantly improved agreement between predicted and measured HTCs.