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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
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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!
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Latest News
First astatine-labeled compound shipped in the U.S.
The Department of Energy’s National Isotope Development Center (NIDC) on March 31 announced the successful long-distance shipment in the United States of a biologically active compound labeled with the medical radioisotope astatine-211 (At-211). Because previous shipments have included only the “bare” isotope, the NIDC has described the development as “unleashing medical innovation.”
Zhiwen Xu, Michael J. Driscoll, Mujid S. Kazimi
Nuclear Science and Engineering | Volume 141 | Number 3 | July 2002 | Pages 175-189
Technical Paper | doi.org/10.13182/NSE02-A2277
Articles are hosted by Taylor and Francis Online.
To provide guidance for future light water reactor core design and fuel management strategies, the effects of the moderator-to-fuel ratio on burnup, core endurance, and waste disposal characteristics have been investigated. The analysis is based on a unit cell model of the standard four-loop Westinghouse pressurized water reactor (PWR) with varied water density, rod diameter, and lattice pitch. Two state-of-the-art computer codes, CASMO-4 and MOCUP (MCNP+ORIGEN), have been used. Considering the entire range of moderation (from fast spectra to overthermalized spectra), the results show that higher reactivity-limited burnup is achievable by either a wetter lattice or a much drier lattice than normal. In particular, epithermal lattices are distinctly inferior performers. Current PWR lattices are about the optimum in terms of highest fuel endurance. However, wetter lattices produce less plutonium with a degraded plutonium isotopic mix with respect to weapons usability. Neptunium-237 content is only mildly affected by the hydrogen-to-heavy-metal ratio. High burnup is significantly beneficial to reducing plutonium production per unit energy and to making its isotopic mix less attractive as a weapon material. In particular, the 238Pu to 239Pu ratio increases approximately as the 2.5 power of burnup for a fixed initial enrichment. Based on this neutronics study, wetter lattices are recommended for future high-burnup applications.