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
Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
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.
J. Stepanek , M. Segev
Nuclear Science and Engineering | Volume 108 | Number 3 | July 1991 | Pages 215-229
Technical Paper | doi.org/10.13182/NSE91-A23820
Articles are hosted by Taylor and Francis Online.
A surface current methodology is developed to respond to the need for treating the various levels of material heterogeneity in a double-heterogeneous multilayer multicell in processing neutron multigroup cross sections in the resonance as well as in the thermal energy range. First, the basic surface cosine current transport equations to calculate the energy-dependent neutron flux spatial distribution in the multilayered multicell are formulated. Slab, spherical, and cylindrical geometries, as well as square and hexagonal lattices and pebble-bed configurations with white or reflective cell boundary conditions, are considered., Second, starting from the surface cosine current formulation, a two-zone three-layer multicell formalism for reduction of the heterogeneous flux expressions to equivalent homogeneous flux expressions for the “table” method is developed. The “outer (right side)” as well as “inner (left side)” Dancoff probabilities can be calculated for any particular layer., This formalism allows an infinite as well as a limited number of second-heterogeneity cells within a partial first-heterogeneity cell layer to be considered. Also, the number of the first- as well as second-heterogeneity cell types is quite general., An accurate, efficient, and compact interpolation procedure is used to calculate the basic collision probabilities. These are transmission and escape probabilities for shells in slab, cylindrical, and spherical geometries, as well as Dancoff probabilities for cylinders in square and hexagonal lattices., The use of the interpolation procedure is exemplified in a multilayer multicell approximation for the Dancoff probability, enabling a routine evaluation of the equivalence-based shielded resonance integral in highly complex lattices of slab, cylindrical, or spherical cells.