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Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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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.
Mohamed Belhadj, Tunc Aldemir, Richard N. Christensen
Nuclear Technology | Volume 95 | Number 1 | July 1991 | Pages 95-102
Technical Paper | Heat Transfer and Fluid Flow | doi.org/10.13182/NT91-A34571
Articles are hosted by Taylor and Francis Online.
Plate-type research reactor cores have involute or rectangular coolant channels with channel gap size in the range 2 ≤ d ≤ 5 mm. Heat transfer under fully developed nucleate boiling (FDNB) and low-velocity (<0.15 m/s) upward flow conditions is important in accident situations where core cooling may be by natural convection. Using data from previous experimental work with 2 ≤ d ≤ 4 mm rectangular channels, it is shown that (a) wall superheat (ΔTsat) in thin channels under FDNB decreases with increasing probability of bubble contact, (b) ΔTsat is a function of the bubble departure diameter Db as well as d, and (c) ΔTsat can be significantly overestimated by the FDNB correlations that are conventionally used in plate-type research reactor analysis but that are based on higher pressure and larger d flow data and that predict ΔTsat as a function of local channel heat flux and pressure only (e.g., as in the Jens-Lottes and Thom correlations). A new FDNB correlation is proposed that represents the bubble contact mechanism through the dimensionless number (d — cDb)/d, where c is a fitting parameter that accounts for the statistical aspects of bubble formation and contact. The ΔTsat predictions of the new correlation agree with the experimental data to within 16% and approach those obtained from the Jens-Lottes correlation with decreasing Db/d.
