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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.
Raymond S. Troy, Robert V. Tompson, Tushar K. Ghosh, Sudarshan K. Loyalka, Nidia C. Gallego
Nuclear Technology | Volume 189 | Number 3 | March 2015 | Pages 241-257
Technical Paper | Reactor Safety | doi.org/10.13182/NT14-25
Articles are hosted by Taylor and Francis Online.
Characterization of graphite particles (dust) produced by abrasion that would occur in a pebble bed reactor is of interest for reasons of safety, operation, and maintenance. To better understand this abrasion and particle generation, we have built a test apparatus to produce particles by sliding abrasion in a 1% to 5% relative humidity air environment. We have used a commercial-grade graphite in our experiments and have generated size distributions for the abraded particles. We have also fit lognormal functions to those size distributions (for use in computer codes); determined particle shapes; measured temperature and humidity during the tests; measured and calculated wear rates; and measured the surface roughness of both pretest and posttest samples, particle surface areas, pore volumes, and pore volume distributions of particles produced during abrasion of graphite surfaces under different loadings and sliding speeds. The experiments showed that as loading (analogous to pebble depth in the reactor) and sliding speed increase, so do the wear rates and numbers of particles produced, while surface roughness decreases, increases, and then decreases. Brunauer-Emmett-Teller measurements show that abrasion increases surface area from 0.583 m2/g in the bulk material to 555 m2/g in material abraded at high loading and high sliding speed. Wear rates range from 0.005 to 0.991 g/m per contact site. The size of the particles observed was <4000 nm. In all, our research shows that pebble abrasion is a complex process that is not constant during operation and thus should be considered for future work.