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.
Explore membership for yourself or for your organization.
Conference Spotlight
2025 ANS Winter Conference & Expo
November 8–12, 2025
Washington, DC|Washington Hilton
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
Nov 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
December 2025
Nuclear Technology
November 2025
Fusion Science and Technology
Latest News
White House taps Douglas Weaver for NRC role
The Trump White House has nominated seasoned nuclear regulatory expert Douglas Weaver for a commissioner seat on the Nuclear Regulatory Commission. If confirmed, Weaver would fill the seat vacated by NRC commissioner Annie Caputo, who resigned in July.
Weaver’s nomination was sent earlier today to the Senate Environment and Public Works Committee. If confirmed, he would finish the remainder of Caputo’s term, which expires June 30, 2026.
Hans Ludewig
Nuclear Science and Engineering | Volume 44 | Number 1 | April 1971 | Pages 18-26
Technical Paper | doi.org/10.13182/NSE71-A18901
Articles are hosted by Taylor and Francis Online.
An analysis of five metal critical assemblies constructed at the Los Alamos Scientific Laboratory is described in this paper. Nuclear data based on ENDF/B Versions 1 and 2 and the DSN method are used in the analysis. Special attention is focused on the variation of α (the ratio of capture-to-fission cross sections) for 239Pu. A study of the sensitivity of keff to the number of angular quadratures and the scattering model used in the calculation is also investigated. Finally, in addition to determining the reactivity of each core, the spatial variation of a spectral index for two cores is investigated.