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
Accelerator Applications
The division was organized to promote the advancement of knowledge of the use of particle accelerator technologies for nuclear and other applications. It focuses on production of neutrons and other particles, utilization of these particles for scientific or industrial purposes, such as the production or destruction of radionuclides significant to energy, medicine, defense or other endeavors, as well as imaging and diagnostics.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
June 2025
Nuclear Technology
Fusion Science and Technology
May 2025
Latest News
Argonne’s METL gears up to test more sodium fast reactor components
Argonne National Laboratory has successfully swapped out an aging cold trap in the sodium test loop called METL (Mechanisms Engineering Test Loop), the Department of Energy announced April 23. The upgrade is the first of its kind in the United States in more than 30 years, according to the DOE, and will help test components and operations for the sodium-cooled fast reactors being developed now.
Masao Yamanaka, Cheol Ho Pyeon, Tsuyoshi Misawa
Nuclear Science and Engineering | Volume 184 | Number 4 | December 2016 | Pages 551-560
Technical Paper | doi.org/10.13182/NSE15-107
Articles are hosted by Taylor and Francis Online.
In an accelerator-driven system (ADS), the effective delayed neutron fraction βeff is required for subcriticality measurements in order to convert measured reactivity in dollar units into pcm units. Here, an alternative calculation methodology with source-dependent reaction rates is proposed to estimate the subcriticality (pcm units) with an external neutron source for the newly defined parameter βRRsource . In the proposed methodology, the parameter is obtained by the k-ratio method with reaction rates considering the external neutron source (fixed-source calculation) and is compared with that obtained by the eigenvalue calculations (MCNP6.1). To investigate its applicability to the estimation of subcriticality, subcriticality measurements by the extrapolated area ratio method are carried out in the experiments in ADS at the Kyoto University Critical Assembly, with the variation of subcriticality (pcm units) and the spectrum of the external neutron source. Then, βRRsource is estimated by the proposed methodology with MCNPX-2.5.0. The measured subcriticality with the use of βRRsource obtained by the fixed-source calculations shows good agreement with that obtained by the different measurement methodology and MCNPX-2.5.0. Through the subcriticality estimation, the applicability of the proposed methodology is confirmed for different subcriticality levels and the spectrum of the external neutron source.
