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 Nonproliferation Policy
The mission of the Nuclear Nonproliferation Policy Division (NNPD) is to promote the peaceful use of nuclear technology while simultaneously preventing the diversion and misuse of nuclear material and technology through appropriate safeguards and security, and promotion of nuclear nonproliferation policies. To achieve this mission, the objectives of the NNPD are to: Promote policy that discourages the proliferation of nuclear technology and material to inappropriate entities. Provide information to ANS members, the technical community at large, opinion leaders, and decision makers to improve their understanding of nuclear nonproliferation issues. Become a recognized technical resource on nuclear nonproliferation, safeguards, and security issues. Serve as the integration and coordination body for nuclear nonproliferation activities for the ANS. Work cooperatively with other ANS divisions to achieve these objective nonproliferation policies.
Meeting Spotlight
2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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
Aug 2024
Jan 2024
Latest Journal Issues
Nuclear Science and Engineering
October 2024
Nuclear Technology
Fusion Science and Technology
August 2024
Latest News
New laws offer nuclear industry incentives for existing power plant uprates
This year, the U.S. nuclear industry received a much-needed economic boost that could help preserve operating nuclear power plants and incentivize upgrades that extend their lifespan and power output.
Signed into law in 2022, the Inflation Reduction Act offers production tax credits (PTCs) for existing nuclear power plants and either PTCs or investment tax credits (ITCs) for new carbon-free generation. These credits could make power uprates—increasing the maximum power level at which a commercial plant may operate—a much more appealing option for utilities.
H. I. Liou, R. E. Chrien
Nuclear Science and Engineering | Volume 62 | Number 3 | March 1977 | Pages 463-478
Technical Paper | doi.org/10.13182/NSE77-A26985
Articles are hosted by Taylor and Francis Online.
Designers of thermal-neutron reactors have always had to adjust microscopic nuclear cross sections to predict neutron multiplication in slightly enriched uranium lattices. It has been surmised that the problem lies in an overestimation of the neutron capture cross section of 238U below 100 eV. We have measured these cross sections by three independent experiments. First, a series of neutron transmission and self-indication measurements were taken on samples of 238U ranging from 10.79 to 11 620 b/atom in inverse thickness. The level parameters were obtained using area analysis and multilevel fits. Next, the capture cross sections deduced from these level parameters were confirmed by direct measurements on both the continuum and discrete line portions of the low-energy gamma-ray spectra. High resolution measurements on the gamma-ray spectra were carried out from 530 to 900 keV over the neutron energy range from near thermal to ∼20 eV. Finally, a further check was made by activating thin samples of 238U with monochromatic neutrons obtained by Bragg scattering. The result is consistent with the capture cross sections obtained by the gamma-ray spectra measurement. Our results reduce, by 25%, the shielded capture integral discrepancy observed in early Bettis Atomic Power Laboratory critical experiments (TRX) with low-235U-enriched uranium rods latticed in water. When they are coupled with refined lattice calculations, much of the long-standing discrepancy is removed.