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The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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.”
José Canosa, Harvey Brooks
Nuclear Science and Engineering | Volume 26 | Number 2 | October 1966 | Pages 237-253
Technical Paper | doi.org/10.13182/NSE66-A28166
Articles are hosted by Taylor and Francis Online.
The xenon-induced oscillations in the power level (fundamental mode) and in the power distribution (first harmonic) have been studied for a slab reactor with prompt power reactivity feedback. One-group space-dependent kinetics equations and linearized theory are used throughout. The linear analysis rigorously predicts the onset of xenon oscillations; however, it does not say anything on how much the oscillation amplitude grows or decays. Explicit formulas giving the effects of the coupling of the infinite number of reactor modes with the fundamental mode and first harmonic are obtained and used for the first time to explain mode-coupling effects both qualitatively and quantitatively. Mode-coupling effects are quite small at the thermal flux levels of present power reactors [1013−1014 n/(cm2sec)]. At higher fluxes [1015 n/(cm2sec)] mode coupling is destabilizing and might be significant; here the negative feedback reactivity needed to provide stability must be increased by ≈ 10%, relative to the value obtained from a calculation where coupling is neglected. A study has been made on the influence of the equilibrium power distribution on both types of oscillations; this study gives information concerning the effects of a reflector on reactor kinetics. A new result is that, depending on flux level, a reflected reactor may be more stable than a bare reactor against fundamental mode oscillations.
