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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
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Fusion Science and Technology
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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.”
A. Nicolai, P. Börner
Fusion Science and Technology | Volume 12 | Number 1 | July 1987 | Pages 119-136
Technical Paper | Blanket Engineering | doi.org/10.13182/FST87-A25056
Articles are hosted by Taylor and Francis Online.
The main objective of this numerical study is to investigate how to minimize the tritium content in the first wall of a tokamak reactor. Mainly pulsed tokamak operation with 100-s cycle durations, 75-s duty times, and outgassing phases with durations τg between 500 and 3000 s is envisaged. These outgassing phases are started after every Np cycle (20 < Np < 70). For modeling, a multicode is applied that describes the surface and volume processes determining the tritium inventory in and the permeation through the first wall, the neutral gas background due to the recycling of the plasma, and the transport processes governing the parameters of a three-species burning plasma. The calculations show that control of the wall temperature Tw, determined by the heat transfer to the coolant and the radiation loading by the plasma, is decisive for the tritium buildup. Cooling is achieved by pressurized water or helium at a pressure pHe = 30 bar. The coolant channels are assumed to be composed of a corrugated steel sheet and the first wall, both connected in a panel-type construction. The main results are as follows: 1. In long outgassing phases (τg = 3000 s, Np = 70) at elevated temperatures (Tw = 300° C), the tritium content (˜20 g) after 1400 pulses is ˜2.5 times lower than in continuous irradiation with time-averaged intensity. 2. Shorter but more frequent outgassing phases, e.g., τg = 500 s, Np = 20, are less efficient. 3. Good outgassing efficiency at elevated temperatures is obtained at the expense of an enhanced tritium permeation to the outside. 4. An oxide layer, acting as an ideal diffusion barrier at the outside of the vessel, prevents permeation but effects a tritium content 30% higher than in case 1.