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Division Spotlight
Accelerator Applications
The division was organized to promote the advancement of knowledge of the use of particle accelerator technologies for nuclear and other applications. It focuses on production of neutrons and other particles, utilization of these particles for scientific or industrial purposes, such as the production or destruction of radionuclides significant to energy, medicine, defense or other endeavors, as well as imaging and diagnostics.
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.”
Stephen M. Bajorek, Nikolay Petkov, Katsuhiro Ohkawa, Robert M. Kemper, Arthur P. Ginsberg
Nuclear Technology | Volume 136 | Number 1 | October 2001 | Pages 50-62
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT01-A3228
Articles are hosted by Taylor and Francis Online.
Since the 1988 Appendix K Rulemaking change, there has been significant interest in the development of codes and methodologies for "best-estimate" analysis of loss-of-coolant accidents (LOCAs). Most development has been directed toward large-break (LB) LOCAs (LBLOCAs), since for most pressurized water reactors (PWRs), the LBLOCA generates the limiting peak cladding temperature (PCT). As plants age, are uprated, and continue to seek improved operating efficiencies, the small break (SB) LOCA (SBLOCA) and intermediate-break (IB) LOCA (IBLOCA) can become a concern.Modifications have been made to the WCOBRA/TRAC-MOD7A code to enable it to make realistic calculations of SBLOCAs and IBLOCAs in a Westinghouse PWR. The MOD7A version has recently been approved for use as part of the Westinghouse best-estimate LOCA methodology for LBLOCAs. Thus, the modifications and improvements potentially allow LOCA calculations ranging from SBLOCAs to LBLOCAs using a single code version.The WCOBRA/TRAC-MOD7A, Rev. 4 SB02 version was used to calculate the transient response of a four-loop PWR for a range of break sizes located at the bottom of one of the cold legs. The break sizes ranged from a 0.051-m (2-in.) to a 0.406-m (16-in.) equivalent hole diameter. Each calculation was performed assuming American Nuclear Society (ANS) 1979 decay heat. The plant input assumed the loss of one train of safety injection as well as a power shape that was highly top skewed, which imposed some conservatism on the calculations but allowed a meaningful comparison to Appendix K-type analysis results. The realistic SBLOCA and IBLOCA results showed significantly reduced PCTs compared to those typically obtained from Appendix K LOCA calculations. The realistic results also can be categorized into four separate types of breaks, from a conventional slowly draining SBLOCA to an LBLOCA.