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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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ANS joins others in seeking to discuss SNF/HLW impasse
The American Nuclear Society joined seven other organizations to send a letter to Energy Secretary Christopher Wright on July 8, asking to meet with him to discuss “the restoration of a highly functioning program to meet DOE’s legal responsibility to manage and dispose of the nation’s commercial and legacy defense spent nuclear fuel (SNF) and high-level radioactive waste (HLW).”
K. D. KUCZEN, T. R. BUMP
Nuclear Science and Engineering | Volume 2 | Number 2 | April 1957 | Pages 181-198
Technical Paper | doi.org/10.13182/NSE57-A25386
Articles are hosted by Taylor and Francis Online.
Local heat transfer coefficients were measured in a circular, copper tube of inner diameter 0.25 in., outer diameter 0.55 in., and length 36 in. Direct resistance heating of the tube wall from a direct current power source dictated the size and material of the test section. Since the electrical resistivity of copper varies appreciably with temperature, the radial heat flux was nonuniform along the length. (The temperature drop across the tube wall was small; therefore the heat flux in the radial direction was assumed uniform.) The test section was cooled from the inside with the eutectic alloy of sodium and potassium (22% Na, 78% K) flowing turbulently in a vertical direction. The range of variables covered in the experiment was as follows : fluid temperature from 85° to 1175°F, fluid velocity 4 to 60 ft/sec, Reynolds number 13,000 to 466,000, Peclet number 268 to 3850, average heat flux 28,600 to 3,200,000 Btu/(hr ft2). The maximum local heat flux was 6,000,000 Btu/(hr ft2). For the above test conditions the experimentally measured Nusselt numbers ranged from 1.4 at the low Peclet number to 22.4 at the high Peclet number. Most of the fully-developed Nusselt numbers found are lower than indicated by the Lyon-Martinelli equation, but are in quite good agreement with data of most other experimenters. The values of Nusselt number in the entrance region are about 40% higher than those predicted by Deissler, and approximately 10% higher than the data of Johnson, Hartnett, and Clabaugh. Near a Peclet number of 300, the Nusselt numbers observed were lower, by a factor of more than two, than the theoretical minimum for fully developed laminar flow. The reason for this abnormality has not been established.