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
July 2025
Latest News
Spent fuel transfer project completed at INL
Work crews at Idaho National Laboratory have transferred 40 spent nuclear fuel canisters into long-term storage vaults, the Department of Energy’s Office of Environmental Management has reported.
Jesse C. Holmes, Ayman I. Hawari, Michael L. Zerkle
Nuclear Science and Engineering | Volume 184 | Number 1 | September 2016 | Pages 84-113
Technical Paper | doi.org/10.13182/NSE15-89
Articles are hosted by Taylor and Francis Online.
The S(α, β) double-differential thermal neutron scattering law tabulated in Evaluated Nuclear Data File (ENDF) File 7 is, by convention, produced theoretically through fundamental scattering physics models. Currently, no published ENDF evaluations contain covariance data for S(α, β) or associated scattering cross sections. Furthermore, no accepted methodology exists for quantifying or representing these covariances. Thermal scattering cross sections depend on the interatomic structure and dynamics of the material. For many solids, the influence of these properties on inelastic scattering cross sections can be adequately described through the phonon energy spectrum. The phonon spectrum can be viewed as a probability density function and is commonly the fundamental input for calculating S(α, β). Probable variation in the shape of the phonon spectrum may be established that characterizes uncertainties in the physics models and methodology employed in its production. Through Monte Carlo sampling of perturbations from the reference phonon spectrum, an S(α, β) covariance matrix may be generated. With appropriate sensitivity information, the S(α, β) covariance matrix can be propagated to generate covariance data for differential and integral cross sections. In this work, hexagonal graphite is used as an example material for demonstrating the proposed procedures for analyzing, calculating, and processing uncertainty information for theoretically generated thermal neutron inelastic scattering data.