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Materials Science & Technology
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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.”
William T. Sha, Alan E. Waltar
Nuclear Science and Engineering | Volume 44 | Number 2 | May 1971 | Pages 135-156
Technical Paper | doi.org/10.13182/NSE71-A19663
Articles are hosted by Taylor and Francis Online.
A two-dimensional (R - Z) integral model for characterizing fast reactor excursions from accident inception through core disassembly is presented. For predisassembly calculations, a Eulerian geometric model is used and multichannel heat-transfer computations are performed. Reactivity feedback due to Doppler broadening, coolant density change and voiding, and fuel movement are taken into account. A Lagrangian coordinate system is used in the disassembly phase, wherein the neutronics balance consists of Doppler broadening and material motion. A unique feature of the model is the ability to accommodate a pointwise Energy-Density-Dependent Equation-of-State according to the local sodium inventory that actually exists at the time of disassembly. By providing a consistent basis for establishing the effective reactivity ramp rate, Doppler coefficient, appropriate Equation-of-State, and temperature distribution at the start of core disassembly, much of the arbitrariness normally associated with large accident analyses can be removed. For most accident analyses, this model predicts a significantly lower energy yield during a superprompt critical nuclear excursion than would be computed by using the conventional modified Bethe-Tait analysis.