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
2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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
May 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
June 2024
Nuclear Technology
Fusion Science and Technology
Latest News
The busyness of the nuclear fuel supply chain
Ken Petersenpresident@ans.org
With all that is happening in the industry these days, the nuclear fuel supply chain is still a hot topic. The Russian assault in Ukraine continues to upend the “where” and “how” of attaining nuclear fuel—and it has also motivated U.S. legislators to act.
Two years into the Russian war with Ukraine, things are different. The Inflation Reduction Act was passed in 2022, authorizing $700 million in funding to support production of high-assay low-enriched uranium in the United States. Meanwhile, the Department of Energy this January issued a $500 million request for proposals to stimulate new HALEU production. The Emergency National Security Supplemental Appropriations Act of 2024 includes $2.7 billion in funding for new uranium enrichment production. This funding was diverted from the Civil Nuclear Credits program and will only be released if there is a ban on importing Russian uranium into the United States—which could happen by the time this column is published, as legislation that bans Russian uranium has passed the House as of this writing and is headed for the Senate. Also being considered is legislation that would sanction Russian uranium. Alternatively, the Biden-Harris administration may choose to ban Russian uranium without legislation in order to obtain access to the $2.7 billion in funding.
Takanobu Kamei
Nuclear Science and Engineering | Volume 57 | Number 3 | July 1975 | Pages 179-187
Technical Paper | doi.org/10.13182/NSE75-A26749
Articles are hosted by Taylor and Francis Online.
Continuous slowing-down theory is generalized so that inelastic scattering can be accurately taken into account. The basic idea underlying generalized theory is the assumption that the ratio, R(u), of the solution spectrum to a reference spectrum, g(u), varies linearly with the lethargy, u; that is, R(u) can be approximated by two terms of a Taylor series as long as g(u) is chosen reasonably. Such conventional theories as Geortzel-Greuling (GG) or Stacey’s improved-GG are included in this theory by taking g(u) as 1/∑s,i(u) or 1/∑t(u), respectively. The present theory is demonstrated to yield quite accurate results for the neutron spectra and coarse-group effective cross sections in many varieties of core and blanket compositions of fast reactors, using three alternative prescriptions for g(u).
