ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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!
Latest Magazine Issues
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
June 2025
Nuclear Technology
Fusion Science and Technology
May 2025
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.
Michael Jarrett, Brendan Kochunas, Edward Larsen, Thomas Downar
Nuclear Science and Engineering | Volume 193 | Number 12 | December 2019 | Pages 1291-1309
Technical Paper | doi.org/10.1080/00295639.2019.1627176
Articles are hosted by Taylor and Francis Online.
A new method for calculating anisotropic radial transverse leakage (TL) in a two-dimensional (2D)/one-dimensional (1D) transport method is derived and implemented in MPACT. This method makes use of parity in the polar angle only to form the 2D transport equations for the 2D/1D method. The even-parity component is solved on a fine mesh using the method of characteristics (MOC), while the odd-parity component is solved on a coarse mesh using S. The anisotropic radial TL on the coarse cell boundaries is calculated by combining the even- and odd-parity components. The new method is faster than a similar previous method because it delegates half of the work required to calculate the solution of the 2D transport problem to a coarse-mesh S solver, which is more than ten times faster than the fine-mesh MOC solver. The results show that the accuracy of the new method is equivalent to that of the previously implemented method for anisotropic TL, with a significant speedup. With azimuthally isotropic TL, the new method reduces the computational overhead compared to the standard method from 58% to 5% for the three-dimensional (3D) C5G7 benchmark problems. With azimuthally anisotrop\ic TL using Fourier expansion, the new method reduces the overhead from 84% to 37%. This is important because the accuracy of the 2D/1D method is limited by the isotropic TL approximation. With anisotropic TL, the accuracy of 2D/1D is equivalent or comparable to 3D transport, but there is a significant computational cost associated with calculating the anisotropic TL. The method presented provides a faster way to calculate the anisotropic TL, giving the 2D/1D method significantly increased accuracy with only a modest increase in computational requirements compared to isotropic 2D/1D.