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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.”
George Tsotridis
Fusion Science and Technology | Volume 32 | Number 1 | August 1997 | Pages 35-44
Technical Paper | First-Wall Technology | doi.org/10.13182/FST97-A19878
Articles are hosted by Taylor and Francis Online.
Plasma-facing components in tokamak-type fusion reactors are subjected to intense heat loads during plasma disruptions, which causes melting and evaporation of the surface layer. The influence of the beam cross section of the incident energy on the depths of heat-affected zones on pure tungsten metal has been studied by using a two-dimensional transient computer model that solves the equations of motion and energy. Results are presented for relatively long disruption times for different beam cross sections and for a range of energy densities. It is demonstrated that there exists a critical value of cross-section area beyond which any further increase has no appreciable influence on the resulting depths of molten layers. It is also demonstrated that as the cross section increases, the convective flows caused by surface tension gradients resulting from variations of surface impurities are confined at regions close to the periphery of the molten zone, whereas at the center of the molten pool, heat is transported in the molten metal by conduction. It is demonstrated that by increasing the beam cross-section area, the resulting depths of molten layers increase. However, there exists a critical value of cross section beyond which the resulting molten layer depths are invariant to the beam cross section. It is further appreciated that there are other important phenomena taking part during plasma disruptions, such as electromagnetic forces, but at this stage, such influences on the molten layers will not be studied. Nevertheless, the influence of the beam cross-sectional area would be of similar importance.