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Division Spotlight
Accelerator Applications
The division was organized to promote the advancement of knowledge of the use of particle accelerator technologies for nuclear and other applications. It focuses on production of neutrons and other particles, utilization of these particles for scientific or industrial purposes, such as the production or destruction of radionuclides significant to energy, medicine, defense or other endeavors, as well as imaging and diagnostics.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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
Argonne’s METL gears up to test more sodium fast reactor components
Argonne National Laboratory has successfully swapped out an aging cold trap in the sodium test loop called METL (Mechanisms Engineering Test Loop), the Department of Energy announced April 23. The upgrade is the first of its kind in the United States in more than 30 years, according to the DOE, and will help test components and operations for the sodium-cooled fast reactors being developed now.
Richard Sanchez, Jean Ragusa
Nuclear Science and Engineering | Volume 169 | Number 2 | October 2011 | Pages 133-154
Technical Paper | doi.org/10.13182/NSE10-31
Articles are hosted by Taylor and Francis Online.
An angular approximation of the transport equation based on a collocation technique results as an intermediary step in the search for a set of modified discrete ordinates (DO) equations, which eliminates ray effects. The collocation equations are similar to the DO ones with the only difference being that the scattering term is evaluated with a full Galerkin matrix instead of with the DO quadrature formula. The Galerkin quadrature offers the advantage of a better treatment of scattering anisotropy and a correct evaluation of the singular scattering associated to multigroup transport correction. However, the construction of the Galerkin matrix requires the existence of two equivalent bases in a final-dimensional representation space: an interpolatory basis to retain the collocative nature of the DO approximation and a spherical harmonic basis to represent scattering terms accurately. Up to now, the relationship between these two bases was heuristic, stemming from trial and errors. In this work we analyze the symmetries of the angular direction set and also use the factorized form of the spherical harmonics to derive a set of necessary conditions for the construction of the spherical harmonic basis. These conditions give an analytical explanation to previous heuristic techniques and fully extend them to three-dimensional geometries. We have adopted an assembling method for which extensive numerical tests show that the necessary conditions permit the construction of the Galerkin quadrature from level-symmetric, triangular, and product direction sets up to a high number of polar cosines. Our results can also be generalized to calculate Galerkin matrices for nonregular quadrature formulas. However, these necessary conditions are not sufficient, and we give numerical proof of this fact using different assembling techniques. Our assembling technique allows for the construction of Galerkin matrices from triangular direction sets (for which the DO quadrature is notoriously poor), which have positive weights for up to 44 polar cosines. In three dimensions this quadrature has 2024 angular directions and is able to exactly integrate scattering of anisotropy order 24.
