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Division Spotlight
Robotics & Remote Systems
The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
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.
Jonas Berger, Alexander Mühle, Kai-Martin Haendel
Nuclear Science and Engineering | Volume 194 | Number 6 | June 2020 | Pages 415-421
Technical Paper | doi.org/10.1080/00295639.2019.1705656
Articles are hosted by Taylor and Francis Online.
During the lifetime of fuel assemblies, irradiation and fluid mechanical forces can cause a permanent deformation in the lateral direction that leads to larger interassembly water gaps in the reactor core. The standard reload safety analysis for the reactor core is developed for a uniform distribution of corewise interassembly water gaps. A nonuniform distribution of water gaps with locally larger or smaller water gaps could lead to a significant change in the positions of the hot-spot factors. Thus, such modifications could also impact boundary conditions for safety analysis or boundary conditions of the reactor core surveillance systems. To analyze the impact of a nonuniform water-gap distribution on the safety analysis and the reactor core surveillance systems, TÜV Nord EnSys is developing a new methodology that allows the incorporation of assembly bow effects in core analysis. For this methodology, functions linking the maximal relative power increase in the vicinity of the modified water gap to the fuel properties had to be derived. This was accomplished by simulating for gaps between different fuel types at selected positions in a full-core model of a generic four-loop Siemens/Kraftwerk Union pressurized water reactor using the bow model of the two-group diffusion code SIMULATE-3. The data of the maximal relative power increase were linearly correlated with the spectral indices and the coolant densities of the two gap-adjacent assemblies. Then a function was derived that provides a firsthand approximation of the maximal relative power increase using only the physical properties of the unbowed core configuration. The maximal absolute positive deviation of the function from the simulation results was 2.4%.