ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
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!
Latest Magazine Issues
Jul 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
August 2024
Nuclear Technology
Fusion Science and Technology
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 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. 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.”
Song Hyun Kim, Hong-Chul Kim, Jong Kyung Kim, Jea Man Noh
Nuclear Technology | Volume 177 | Number 2 | February 2012 | Pages 147-156
Technical Paper | Fission Reactors | doi.org/10.13182/NT12-A13362
Articles are hosted by Taylor and Francis Online.
The Dancoff factor is used in deterministic codes for the calculation of resonance absorption. In using the Monte Carlo simulation, some techniques, such as repeated structure, are commonly used for geometry modeling of pebbles and kernels. However, these methods, with some assumptions, can cause an error in the calculation of the Dancoff factor. In this study, a Monte Carlo simulation method for the evaluation of the Dancoff factor was developed to solve these problems. Random sampling and rejection techniques are used for geometry modeling of pebbles and kernels. Also, the random selection method of the pebble type is used for modeling of the fuel and moderator pebbles that are randomly mixed in the core. By using this method, the Dancoff factor was calculated, and the results were compared with the results calculated by the INTRAPEB code and the MCNP5 code. The results of the average intrapebble Dancoff factor agree well within 1% difference compared with the result of the other study that was calculated by the INTRAPEB code. The result of the average interpebble Dancoff factor was underestimated by [approximately]8%, compared with the result by using the MCNP5 code. Analysis shows that the difference is caused by modeling assumptions in using the MCNP5 code. In addition, the Dancoff factor of the HTR-PRTEUS reactor and its spatial dependency were evaluated. The results show that the method can be used in the calculation of the Dancoff factor with the consideration of the spatial dependency with good accuracy. It is expected that the method can simply calculate the average Dancoff factor calculation without the direct modeling of the complex pebble bed reactor geometries. Also, the Monte Carlo simulations with various fuel-to-moderator ratios can be evaluated. Therefore, it will be a powerful method to evaluate the Dancoff factor with consideration of a real geometrical distribution for the pebble bed reactors.