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.
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.
2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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
Latest Journal Issues
Nuclear Science and Engineering
Fusion Science and Technology
Finland in Front: The World’s Likely First Spent Fuel Repository Moves Toward Licensing
The year 2024 is shaping up to be a historic one for Posiva, the waste management organization owned by Finland’s two nuclear power plant utilities, Fortum and Teollisuuden Voima. The company is looking to receive regulatory approval of its operating license for the Onkalo deep geological repository for high-level radioactive waste by the end of the year.
M. Fukushima, J. Goda, A. Oizumi, J. Bounds, T. Cutler, T. Grove, D. Hayes, J. Hutchinson, G. McKenzie, A. McSpaden, R. Sanchez, J. Walker, K. Tsujimoto
Nuclear Science and Engineering | Volume 194 | Number 2 | February 2020 | Pages 138-153
Technical Paper | doi.org/10.1080/00295639.2019.1663089
Articles are hosted by Taylor and Francis Online.
To validate lead (Pb) nuclear cross sections, a series of integral experiments to measure lead void reactivity worth was conducted systematically in three fast neutron spectra with different fuel compositions on the Comet critical assembly of the National Criticality Experiments Research Center. Previous experiments in high-enriched uranium (HEU)/Pb and low-enriched uranium (LEU)/Pb systems had been performed in 2016 and 2017, respectively. A follow-on experiment in a plutonium (Pu)/Pb system has been completed. The Pu/Pb system was constructed using lead plates and weapons-grade Pu plates that had been used in the Zero Power Physics Reactor (ZPPR) of Argonne National Laboratory until the 1990s. Furthermore, the HEU/Pb system was reexamined on the Comet critical assembly with a newly installed device that can measure the compression of the stack, improving reproducibility. Using the lead void reactivity worth measured in these three cores with different fuel compositions, the latest nuclear data libraries, JENDL-4.0 and ENDF/B-VIII.0, were tested with the Monte Carlo calculation code MCNP® version 6.1. As a result, the calculations by ENDF/B-VIII.0 were confirmed to agree with lead void reactivity worth measured in all the cores. It was furthermore found that the calculations by JENDL-4.0 overestimate by more than 20% for the Pu/Pb core while being in good agreement for the HEU/Pb and LEU/Pb cores.