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
Young Members Group
The Young Members Group works to encourage and enable all young professional members to be actively involved in the efforts and endeavors of the Society at all levels (Professional Divisions, ANS Governance, Local Sections, etc.) as they transition from the role of a student to the role of a professional. It sponsors non-technical workshops and meetings that provide professional development and networking opportunities for young professionals, collaborates with other Divisions and Groups in developing technical and non-technical content for topical and national meetings, encourages its members to participate in the activities of the Groups and Divisions that are closely related to their professional interests as well as in their local sections, introduces young members to the rules and governance structure of the Society, and nominates young professionals for awards and leadership opportunities available to members.
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.
Alan H. Wells, Albert J. Machiels
Nuclear Technology | Volume 176 | Number 3 | December 2011 | Pages 387-394
Technical Paper | Radiation Transport and Protection | doi.org/10.13182/NT11-A13315
Articles are hosted by Taylor and Francis Online.
According to the U.S. Nuclear Regulatory Commission's guidance based on concerns for potential channeling of neutrons between absorber particles, the criticality safety of transportation systems should not rely on credit for >75% of the boron in fixed neutron absorbers. The 75% efficiency (or effectiveness) factor was first formulated in 1987 for a cask to transport spent fuel from the Fermi Unit 1 (Fermi-1) fast breeder reactor. Fermi-1 fuel was highly enriched (25.6 wt%), and a critical condition could possibly be achieved in a dry environment. The 75% factor was later expanded to include low-enriched light water reactor (LWR) spent fuel, although the latter cannot achieve a critical state without the presence of a moderator. Under flooded conditions, the net effect of channeling is significantly reduced because the neutrons are nearly isotropically scattered by the moderator and impact the neutron absorber from all possible directions. Under dry conditions or under conditions representative in neutron attenuation measurements for absorber qualification, the neutrons impact the absorber mostly perpendicularly, and neutron channeling is maximized. The effect of neutron channeling for the Fermi-1 fuel and for a typical LWR fuel shipment was quantified using a methodology developed to apply experimental transmission data to calculations of the neutron angular distribution at the neutron absorber sheet, yielding the strength of the neutron channeling effect for a particular fuel type and cask basket geometry. These analyses show that neutron absorber qualification via a collimated neutron transmission measurement conservatively bounds the neutron channeling effect. Further imposition of a 75%-only credit leads to an overly conservative amount in neutron absorbers. For transport applications of LWR spent fuel, this results in increased costs with no measurable benefits to criticality safety.