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Radiation Protection & Shielding
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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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.”
H. Guo, P. Sciora, T. Kooyman, L. Buiron, G. Rimpault
Nuclear Technology | Volume 205 | Number 11 | November 2019 | Pages 1433-1446
Technical Paper | doi.org/10.1080/00295450.2019.1620054
Articles are hosted by Taylor and Francis Online.
Generation IV reactors are expected to exhibit significant safety improvements compared to current ones. In sodium-cooled fast reactors (SFRs), fuel melting during transient over power (TOP) should be avoided as this is identified as a relatively frequent accident. Among these TOP accidents, a control rod withdrawal (CRW) accident is the most likely to happen and its impact depends on the magnitude of the inserted reactivity. This paper presents the required excess reactivity for different core designs and the way to reduce the reactivity inserted during a CRW transient through the use of burnable poisons (BPs).
After evaluating various candidate materials, it appears that a low-enrichment boron carbide combined with a zirconium hydride moderator is the most promising BP for use in sodium fast spectrum reactors. Burnable poisons are located in pins of particular assemblies, which are in fixed positions in the core over the entire fuel cycle.
Four core designs with different loading schemes and BPs are investigated. Core designs with BPs display low reactivity loss over the fuel cycle and thus limit the required initial excess reactivity of the core to compensate with control rods.
Another constraint comes from the core power distribution, which should remain almost stable through the fuel cycle. This core power distribution can be modified by a suitable loading of BP assemblies. However, as their positions are fixed over the fuel cycle, they can compensate only part of the local flux tilt. These BP core designs slightly improve the reactivity feedback coefficients as they contain light materials slowing down neutrons. It is finally shown that a CRW transient with BPs reduces significantly the maximal fuel centerline temperature compared to a design without BPs and that a fuel melting during a CRW transient is avoided in the large SFR core.