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Division Spotlight
Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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.”
Kwang-Il Ahn, Hee-Dong Kim
Nuclear Technology | Volume 130 | Number 2 | May 2000 | Pages 132-144
Technical Paper | Reactor Safety | doi.org/10.13182/NT00-A3082
Articles are hosted by Taylor and Francis Online.
Continuous efforts to identify and better understand the uncertainties have changed many model parameters and physical phenomena employed in the phenomenological transient models or related computer codes to be estimated by more detailed models. Since their true forms are often not known, however, different modeling assumptions have resulted in various forms of model elements even for a given phenomenon, allowing for different results in the code predictions. In a situation in which there are no rigorous ways to decide the credibility of a specific model element over another, these different model elements can become additional contributors to an overall uncertainty of the physical model predictions. In recent times, most uncertainty analyses of physical models have been focused on the model parameters, without considering the impact of these different model elements. Such levels of uncertainty analysis can only explore a subspace of the true uncertainty space of physical models, and thus the resultant uncertainty tends to underestimate the magnitude of possible uncertainties. Regarding the modeling sources of uncertainty, on the other hand, a model sensitivity analysis has been conventionally utilized to assess the effects of each model element on the code predictions. However, such types of analysis cannot systematically account for synergistic effects of all constituent model elements on the code predictions. A formal procedure is provided for characterizing probabilistically two different sources of uncertainty addressed in the phenomenological transient models (i.e., parametric and modeling sources) and their statistical propagation to obtain the overall uncertainties in the physical model predictions.