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
Nuclear Installations Safety
Devoted specifically to the safety of nuclear installations and the health and safety of the public, this division seeks a better understanding of the role of safety in the design, construction and operation of nuclear installation facilities. The division also promotes engineering and scientific technology advancement associated with the safety of such facilities.
Meeting 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
Jun 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
August 2025
Nuclear Technology
July 2025
Fusion Science and Technology
Latest News
NRC cuts fees by 50 percent for advanced reactor applicants
The Nuclear Regulatory Commission has announced it has amended regulations for the licensing, inspection, special projects, and annual fees it will charge applicants and licensees for fiscal year 2025.
O. Bouland, H. Derrien, N. M. Larson, L. C. Leal
Nuclear Science and Engineering | Volume 127 | Number 2 | October 1997 | Pages 105-129
Technical Paper | doi.org/10.13182/NSE127-105
Articles are hosted by Taylor and Francis Online.
A Bayesian R-matrix-fitting code called SAMMY is used in a new analysis of the 240Pu neutron cross sections in the 0.02- to 5700-eV energy range. This work aims to resolve the discrepancies revealed by the JEF2 validation studies. A set of experimental data, suitable for the analysis, is determined from preliminary SAMMY analyses of the available experimental data treated individually. Finally, the sequential analysis of the selected transmission, total, and fission cross-section measurements gives an accurate set of resonance parameters. For the 1.056-eV resonance, the analysis of a recent transmission measurement gives parameters very close to those adopted in ENDF/B-VI. In the energy range above 200 eV, the average capture cross section calculated from the present evaluation is in agreement with ENDF/B-VI but is 25% lower than the values of JEF-2 and JENDL-3. A rigorous study of the statistical properties of the resonance parameters is done during this work. Although 158 new resonances are identified by the careful examination of the experimental fission cross-section and transmission data, the value of the average spacing above 2750 eV (D0 = 16.10 eV) shows a 25% loss of resonances compared with the lower energy region (D0 = 12.06 eV). Finally, for the s-wave resonance parameters, this work recommends the following average values: resonance spacing, D0 = 12.06 ± 0.60 eV; strength function, S0 = (1.032 ± 0.071) × 10−4 eV; and capture width, = 31.92 ± 1.6 meV.