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Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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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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General Kenneth Nichols and the Manhattan Project
Nichols
The Oak Ridger has published the latest in a series of articles about General Kenneth D. Nichols, the Manhattan Project, and the 1954 Atomic Energy Act. The series has been produced by Nichols’ grandniece Barbara Rogers Scollin and Oak Ridge (Tenn.) city historian David Ray Smith. Gen. Nichols (1907–2000) was the district engineer for the Manhattan Engineer District during the Manhattan Project.
As Smith and Scollin explain, Nichols “had supervision of the research and development connected with, and the design, construction, and operation of, all plants required to produce plutonium-239 and uranium-235, including the construction of the towns of Oak Ridge, Tennessee, and Richland, Washington. The responsibility of his position was massive as he oversaw a workforce of both military and civilian personnel of approximately 125,000; his Oak Ridge office became the center of the wartime atomic energy’s activities.”
Ronald D. Boyd
Fusion Science and Technology | Volume 13 | Number 4 | May 1988 | Pages 644-653
Technical Paper | Blanket Engineering | doi.org/10.13182/FST88-A25139
Articles are hosted by Taylor and Francis Online.
A quasi-automated high heat flux flow boiling facility has been developed for the systematic study of critical heat flux (CHF), heat transfer, and two-phase pressure drop. High heat flux research is important in state-of-the-art electronics and fusion component design. For fusion applications, there are practically no low-pressure data for large values of coolant channel length-to-diameter (L/D) ratio (i.e., 100), channel diameters near 1.0 cm, and medium to high heat flux levels (i.e., 100 to 2000 W/cm2). A second step is provided to fill this void. Forced flow boiling (with water) quasi-steady experiments have been conducted on uniformly (resistively) heated horizontal copper tubes. The tubes were 1.02 cm in inside diameter and 117.87 cm long. The inlet water temperature was 20°C. For a 1.6-MPa exit pressure, measurements of the CHF varied from the annular flow regime (150 W/cm2) to the subcooled flow boiling regime (425 W/cm2). The mass velocity was varied from 0.63 to 3.5 Mg/m2·s. At 1.6 MPa, the transition between the annular and subcooled CHF regimes was measured to occur between 1.03 and 1.26 Mg/m2·s. Large axial variations in the Nusselt number were also measured. For example, at 1.7 Mg/m2·s, the Nusselt number varied from 120 at the channel's entrance to 500 at the exit. The CHF data were compared with correlations developed by Bowring, Katto, and Merilo. Below 4.0 Mg/m2, all correlations overpredicted the CHF data. Merilo's correlation, which was developed for high-pressure horizontal flows, predicted the CHF significantly above the present low-pressure data. The effects of orientation on the CHF data were small. Visual observations of the outside of the test section showed that burnout occurred simultaneously around the test section's perimeter. Circumferential measurements of the outside wall temperature also showed negligible variations. Therefore, at low pressures, the following conditions reduced the effect of orientation: 1. high liquid Reynolds number 2. high inlet subcooling 3. moderate L/D 4. increased effects of surface tension relative to buoyant and viscous forces at higher pressures (i.e., low Bond and Ohnesorge numbers)5. low value of buoyant forces relative to inertia forces.
