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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
NRC engineers share their expertise at the University of Puerto Rico
Robert Roche-Rivera and Marcos Rolón-Acevedo are licensed professional engineers who work at the U.S. Nuclear Regulatory Commission. They are also alumni of the University of Puerto Rico–Mayagüez (UPRM) and have been sharing their knowledge and experience with students at their alma mater since last year, serving as adjunct professors in the university’s Department of Mechanical Engineering. During the 2023–2024 school year, they each taught two courses: Fundamentals of Nuclear Science and Engineering, and Nuclear Power Plant Engineering.
Kyle Remley, Farzad Rahnema
Nuclear Science and Engineering | Volume 183 | Number 2 | June 2016 | Pages 161-172
Technical Paper | doi.org/10.13182/NSE15-97
Articles are hosted by Taylor and Francis Online.
This paper presents a formulation for a method for the adaptive selection of angular flux expansion orders for use in COarse MEsh radiation Transport (COMET) method solutions to whole-core reactor problems. An important aspect of the COMET method is an assumed angular flux expansion on mesh interfaces. Previously, this expansion was held constant throughout a problem. However, the adaptive method described in this paper chooses the angular flux expansions automatically and allows them to vary between meshes. To demonstrate the method, a pressurized water reactor benchmark problem with UO2 and mixed oxide fuel assemblies is solved. Three different configurations for different insertions of control rods were considered. For all configurations, the agreement between the standard and adaptive COMET solutions was excellent, with eigenvalue agreement being 2 pcm or less and average pin fission errors never exceeding 0.1%. Increases in computational efficiency by factors of 2 to 2.6 were observed over standard COMET solutions employing the full flux expansion considered in the problem. In addition, a lower flux expansion suggested by literature as well as the results of the adaptive calculation was used in the standard COMET method to solve the problem. The adaptive COMET solution has a run time similar to this lower expansion, which is to be expected since many of the flux expansions chosen with the adaptive method match this lower flux expansion. The results of this study are encouraging and imply that adaptive COMET solutions improve upon the standard method by increasing computational efficiency when a flux expansion is used that is higher than required for desired accuracy. The method also limits the need for intuition and numerical experimentation in achieving flux expansions that result in COMET calculations that achieve satisfactory accuracy.