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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.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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
Norway’s Halden reactor takes first step toward decommissioning
The government of Norway has granted the transfer of the Halden research reactor from the Institute for Energy Technology (IFE) to the state agency Norwegian Nuclear Decommissioning (NND). The 25-MWt Halden boiling water reactor operated from 1958 to 2018 and was used in the research of nuclear fuel, reactor internals, plant procedures and monitoring, and human factors.
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.
