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Division Spotlight
Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
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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Nuclear Science and Engineering
August 2024
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July 2024
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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.
Kyoung O. Lee, Robin P. Gardner
Nuclear Science and Engineering | Volume 174 | Number 3 | July 2013 | Pages 264-285
Technical Paper | doi.org/10.13182/NSE12-23
Articles are hosted by Taylor and Francis Online.
Pebble motions in pebble-bed reactors (PBRs) have been investigated by generating pebble motion histories with Monte Carlo molecular dynamics simulations. This extension of molecular dynamics to PBR-sized pebble motion is accomplished by splitting the simulation into two parts. The first part simulates the dropping of pebbles into the PBR with a closed exit that allows one to obtain the correct initial placement of all pebbles within the pebble bed. The second part simulates what happens when the PBR exit is opened and normal pebble flow begins. Using this combined approach the pebble piling up and subsequent discharge are predicted. Simulations have been conducted with this approach by monitoring the mass flow rate, the pebble piling up, and the subsequent discharge for a range of pertinent parameters using the Hertz-Mindlin force for pebble interactions. The simulation output data include the force, velocity, and position of the pebbles as a function of time. Note that arching or locked flow, a very important phenomenon, is predicted by this approach under certain operating conditions. Using this approach, PBR results (including arching) for a range of the parameters of interest are reported and are discussed herein.