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).”
William S. Charlton, William D. Stanbro, R. T. Perry, Bryan L. Fearey
Nuclear Technology | Volume 128 | Number 3 | December 1999 | Pages 285-299
Technical Paper | Fission Reactors | doi.org/10.13182/NT99-A3032
Articles are hosted by Taylor and Francis Online.
The Los Alamos National Laboratory (LANL) has developed a system for determining 237Np, 241Am, and 243Am concentrations in spent fuel from measurements of the 240Pu/239Pu isotopic ratio using calculations performed with the HELIOS lattice-physics code. Benchmark calculations for several pressurized water reactors (PWRs) were performed and compared to measured values from the literature for fuels with burnups ranging from 0 to 50 000 MWd/tonne U. A direct correlation can be found between the 240Pu/239Pu isotopic ratio and the higher-actinide concentrations for each fuel type. Comparisons of calculated with measured values suggests that the LANL technique would yield 237Np and 241Am concentrations within ±5% and 243Am concentrations within ±15% for PWRs. Expanding this system for all reprocessing applications will require more measured data (especially for boiling water reactors and VVER-type reactors), but the existing results show a marked improvement over the previous ORIGEN calculations. Also, a better determination of the 243Am concentrations may support a greater confidence in the calculated results or suggest an alteration to the existing nuclear data. The present state of these neutronics calculations suggests that the technology exists to reduce the need for direct measurement of the 237Np, 241Am, and 243Am concentrations in spent fuel.