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
2026 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
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
Jan 2026
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
January 2026
Nuclear Technology
December 2025
Fusion Science and Technology
November 2025
Latest News
DOE awards $2.7B for HALEU and LEU enrichment
Yesterday, the Department of Energy announced that three enrichment services companies have been awarded task orders worth $900 million each. Those task orders were given to American Centrifuge Operating (a Centrus Energy subsidiary) and General Matter, both of which will develop domestic HALEU enrichment capacity, along with Orano Federal Services, which will build domestic LEU enrichment capacity.
The DOE also announced that it has awarded Global Laser Enrichment an additional $28 million to continue advancing next generation enrichment technology.
David J. Loaiza, Rene Sanchez
Nuclear Science and Engineering | Volume 145 | Number 2 | October 2003 | Pages 256-266
Technical Paper | doi.org/10.13182/NSE03-A2381
Articles are hosted by Taylor and Francis Online.
The basic characteristics of waste materials such as silicon dioxide, aluminum, and iron fueled with highly enriched uranium (HEU) and moderated and reflected by polyethylene were investigated. These critical experiments were performed at the Los Alamos Criticality Experiments Facility. The primary intention of these experiments is to provide supplementary data that can be used to validate and improve criticality data for the Yucca Mountain and the Hanford Storage Waste Tanks Projects. The secondary intention of the 2×2 experiments is to reduce the H/U ratio and increase the waste material/U ratio from previously published experiments. These experiments were designed to supply data for interlaced waste material/fuel/moderator systems on the thermal region. The experiments contained silicon dioxide (SiO2), aluminum (Al), and iron (Fe) mixed with 93.23% enriched uranium and moderated and reflected by polyethylene. This analysis systematically examines uncertainties associated with the critical experiments as they affect the calculated multiplication factor. The systematic analysis is separated into uncertainties due to mass measurements, uncertainties due to fabrication, and uncertainties due to composition. Each type of uncertainty is analyzed individually, and a total combined uncertainty is derived. The SiO2-HEU experiment had a measured keff of 0.993, the Al-HEU experiment had a measured keff of 0.990, and the Fe-HEU experiment had a measured keff of 1.000. The calculated keff values tend to agree well with the experimental values. The sensitivity analysis of these critical experiments yielded a total combined uncertainty on the measured keff of ±0.0044 for SiO2, of ±0.0048 for Al, and of ±0.0046 for Fe.
