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
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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
Jul 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
August 2025
Nuclear Technology
Fusion Science and Technology
Latest News
ANS joins others in seeking to discuss SNF/HLW impasse
The American Nuclear Society joined seven other organizations to send a letter to Energy Secretary Christopher Wright on July 8, asking to meet with him to discuss “the restoration of a highly functioning program to meet DOE’s legal responsibility to manage and dispose of the nation’s commercial and legacy defense spent nuclear fuel (SNF) and high-level radioactive waste (HLW).”
Georg Henneges
Nuclear Science and Engineering | Volume 100 | Number 3 | November 1988 | Pages 314-323
Technical Paper | doi.org/10.13182/NSE88-A29045
Articles are hosted by Taylor and Francis Online.
The reactivity effects of material rearrangements, simulating conditions in a postulated liquid-metal fast breeder reactor accident, were measured in three different critical assemblies. SNEAK-12A, a single-zone core, fueled with enriched uranium metal plates; SNEAK-12B, which had a central test zone fueled with Pu0202 rod bundles surrounded by a buffer and a driver zone; and SNEAK-12C, which had nearly the same integral compositions as SNEAK-12B but was loaded totally with plates. The reactivity effects were calculated using current Kernforschungszentrum Karlsruhe methods and data and, in part, also using the corresponding modules of the SIMMER-11 accident analysis system. Also, for some configurations, a comparison of measured and calculated fission rate distributions was performed., The evaluation yielded similar results for the three assemblies. For most cases investigated, satisfactory agreement between theory and experiment was reached when two-dimensional transport eigenvalue calculations or exact transport perturbation methods were used. As long as larger deviations occurred, transport results generally were on the conservative side. First-order transport perturbation theory only worked well in a limited number of cases. Diffusion calculations often led to large discrepancies, particularly when the experiments involved fuel dilution.