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
Fuel Cycle & Waste Management
Devoted to all aspects of the nuclear fuel cycle including waste management, worldwide. Division specific areas of interest and involvement include uranium conversion and enrichment; fuel fabrication, management (in-core and ex-core) and recycle; transportation; safeguards; high-level, low-level and mixed waste management and disposal; public policy and program management; decontamination and decommissioning environmental restoration; and excess weapons materials disposition.
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!
Latest Magazine Issues
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
May 2025
Nuclear Technology
April 2025
Fusion Science and Technology
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.”
C. H. Reed, C. N. Henry, A. A. Usner
Nuclear Science and Engineering | Volume 30 | Number 3 | December 1967 | Pages 362-373
Technical Paper | doi.org/10.13182/NSE67-A18399
Articles are hosted by Taylor and Francis Online.
Asymptotic decay constants for pulse-induced “thermalized” neutron fields have been measured for graphite cubical assemblies having geometric bucklings varying from 9.30 × 10–4 cm–2 to 13.44 × 10–3 cm–2. A value of 700 μ sec was observed to be a sufficient time after the neutron pulse to identify and evaluate fundamental-mode decay in the smallest system included in the above interval of buckling. Values of the infinite-medium neutron lifetime –1 “Fick’slaw” diffusion coefficient D0, as well as the so-called “diffusion-cooling” coefficient C, were obtained from least-squares fits to the experimental α/ρ vs B2/ρ2 data and are mutually consistent and stable over a large interval of B2 and in good agreement with theory. The existence of a well-defined negative FB6 term has been verified. An “effective” higher-mode decay of (3570 ± 80)sec–1, independent of system buckling, was obtained and is consistent with the concept of a continuum lying above a critical limit for fundamental-mode decay. An apparent critical limit (v ∑ t)min has been identified in the interval 2392 sec–1 < (v ∑ t)min < 2648 sec–1 which corresponds to the interval of buckling 13.44 × 10–3 cm–2 to 16.53 × 10–3 cm–2.