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 Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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’s David Wright visits the Hill and more NRC news
Wright
The Nuclear Regulatory Commission is in the spotlight today for three very different reasons. First, NRC Chair David Wright was on Capitol Hill yesterday for his renomination hearing in front of the Senate’s Environment and Public Works Committee. Second, the NRC released its updated milestone schedules according to the Nuclear Energy Innovation and Modernization Act (NEIMA) and the executive orders signed by President Trump last month; and third, as reported by Reuters on Tuesday, 28 former NRC officials have condemned the dismissal of Commissioner Hanson earlier this month.
Renomination: EPW Committee chair Sen. Shelley Moore Capito (R., W.Va.) opened the hearing with a statement praising Wright’s experience and emphasized the urgency of stable leadership at the NRC.
“China is executing a rapid build-out of its nuclear industry,” Capito said. “The demand for clean, baseload power is skyrocketing as we position America to win the AI race.”
W. F. G. van Rooijen, J. L. Kloosterman, T. H. J. J. van der Hagen, H. van Dam
Nuclear Science and Engineering | Volume 157 | Number 2 | October 2007 | Pages 185-199
Technical Paper | doi.org/10.13182/NSE07-A2721
Articles are hosted by Taylor and Francis Online.
The Generation IV gas-cooled fast reactor (GCFR) is intended to have a closed fuel cycle: During irradiation enough fissile material is produced to allow refueling of the same reactor, adding only fertile material. This is the well-known "zero breeding gain" objective. In this paper a theoretical framework is derived to track compositional changes of the fuel during irradiation, cooldown, and reprocessing, in order to calculate the reactivity of the new fuel compared to the original fuel material. Using first-order perturbation theory, the effect of variations of the initial fuel composition on the reprocessed material and breeding gain can be calculated. The theory is applied to the fuel cycle of a 600 MW(thermal) GCFR. The result is that the change of material composition during cooldown has a nonnegligible effect on the breeding gain. A truly closed fuel cycle can be obtained if the reprocessing efficiency is high enough (<1% loss). If this high efficiency cannot be obtained, adding a small amount of minor actinides (Np, Am, Cm) to the new fuel results in a zero breeding gain. Perturbation theory provides a powerful tool to estimate the effects of changing fuel cycle parameters.