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Division Spotlight
Human Factors, Instrumentation & Controls
Improving task performance, system reliability, system and personnel safety, efficiency, and effectiveness are the division's main objectives. Its major areas of interest include task design, procedures, training, instrument and control layout and placement, stress control, anthropometrics, psychological input, and motivation.
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
September 2024
Nuclear Technology
August 2024
Fusion Science and Technology
Latest News
Taking shape: Fusion energy ecosystems built with public-private partnerships
It’s possible to describe fusion in simple terms: heat and squeeze small atoms to get abundant clean energy. But there’s nothing simple about getting fusion ready for the grid.
Private developers, national lab and university researchers, suppliers, and end users working toward that goal are developing a range of complex technologies to reach fusion temperatures and pressures, confounded by science and technology gaps linked to plasma behavior; materials, diagnostics, and electronics for extreme environments; fuel cycle sustainability; and economics.
Vaibhav Khane, Mahmoud M. Taha, Gary E. Mueller, Muthanna H. Al-Dahhan
Nuclear Technology | Volume 199 | Number 1 | July 2017 | Pages 47-66
Technical Paper | doi.org/10.1080/00295450.2017.1324729
Articles are hosted by Taylor and Francis Online.
In a pebble bed reactor (PBR) core, nuclear fuel in the form of pebbles moves slowly under the influence of gravity. Due to the dynamic nature of the core, a thorough understanding about slow and dense granular flow of pebbles is required from both a reactor safety point of view and a performance evaluation point of view. In the current study, validation of discrete element method (DEM)–based simulation for the pebble flow in a PBR was carried out. Validation of DEM-based simulations necessitates validation of the employed numerical method of simulating packed structure. Hence, a parametric sensitivity study of packing interaction properties was initially conducted and also validation of the numerical method simulating packed structure at first. The parametric sensitivity analysis suggests that static friction characteristics play an important role from a packed/pebble bed structural characterization point of view. In addition, the simulated packed structure approach has shown a good agreement with the available benchmark data. Afterward, the effect of two different half-cone angles of 30 deg and 60 deg on pebble flow field in a PBR was studied by EDEMTM-based simulations. Results of streamlines, velocity radial profiles, and direct observation of discharge indicated a plug-type flow in the upper cylindrical region, whereas results indicated converging-type flow near the bottom conical region. EDEMTM results of granular flow were validated against experimental benchmark data and show a fair agreement in terms of Lagrangian trajectories and velocity profile. Therefore, this validated EDEMTM-based simulation can be used to obtain reliable results of pebble dynamics in a PBR and to enhance understanding of this phenomenon in a PBR. However, additional experimental investigations are recommended to be carried out for different sizes of test reactors, different bottom cone angles, and different sizes of pebbles to further assess DEM simulation results before using them for full-scale reactor simulations.