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Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
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International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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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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Argonne’s METL gears up to test more sodium fast reactor components
Argonne National Laboratory has successfully swapped out an aging cold trap in the sodium test loop called METL (Mechanisms Engineering Test Loop), the Department of Energy announced April 23. The upgrade is the first of its kind in the United States in more than 30 years, according to the DOE, and will help test components and operations for the sodium-cooled fast reactors being developed now.
A. Rastas, J. Saastamoinen
Nuclear Science and Engineering | Volume 36 | Number 3 | June 1969 | Pages 351-360
Technical Paper | doi.org/10.13182/NSE69-A18733
Articles are hosted by Taylor and Francis Online.
Neutron rethermalization has been studied, experimentally and theoretically, in a system intended to reproduce the conditions of the Kottwitz problem. Terphenyl and light water were used as the moderators at the temperatures 223 and 11°C, respectively. The energy spectrum of the angle-dependent neutron flux perpendicular to the plane discontinuity was measured in terphenyl as a function of the distance from the discontinuity by means of an extraction channel and a choppertime-of-flight analyzer. The spatial behavior of the flux-weighted average energy was determined by fitting a Maxwellian to each measured spectrum using the method of the least squares. This spatial behavior could be satisfactorily described by a simple one-exponential function for distances exceeding 3 mm (measured from the discontinuity). The least-squares fit gave a value of 11.3 mm for the relaxation length. The theoretical calculations were performed by an approximate method using the “two overlapping-groups” approximation for the energy dependence. For the angular dependence of the flux, both the Pn(n =1,3)- and the DPn(n = 1)-approximation was used. Three different scattering models were used for each moderator. Rather good agreement with the theory and the experiment was achieved as to both the form of the spectrum and the spatial behavior of the average energy.