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Division Spotlight
Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
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.”
Tamio Kohriyama, Michio Murase, Takashi Nagae, Yukimitsu Okano, Alexandre Ezzidi
Nuclear Technology | Volume 147 | Number 2 | August 2004 | Pages 191-201
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT04-A3525
Articles are hosted by Taylor and Francis Online.
In a severe accident of a light water reactor (LWR), heat transfer models in a narrow gap between superheated core debris and reactor pressure vessel (RPV) are important for evaluating the integrity of the RPV and emergency procedures. Newly developed heat transfer models are discussed that take into account both the local heat flux on a heated surface, which is characterized by the boiling regime, and the average critical heat flux (CHF) on a heated surface, which is restricted by countercurrent flow limitation (CCFL), including the effect of an inclination angle of the gap. The models were incorporated into the mechanistic detailed code RELAP/SCDAPSIM/MOD3.2. The local heat flux was applied to the outer surface of the debris and the inner surface of the RPV wall. The average CHF was evaluated through the CCFL phenomenon at each junction in the gap. For the assessment, an analysis of Japan Atomic Energy Research Institute's ALPHA test was performed. The calculated peak temperature response of the vessel showed good agreement with the experimental data. It was validated that the new models effectively simulate the coolability in a narrow gap, which could be an effective means of cooling the vessel wall and thereby preventing RPV failure, as was demonstrated in the TMI-2 accident.