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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.”
Dan M. Goebel, Joseph Bohdansky, Robert W. Conn, Yoshi Hirooka, Wai Kwong Leung, Richard E. Nygren, George R. Tynan
Fusion Science and Technology | Volume 15 | Number 1 | January 1989 | Pages 102-107
Technical Paper | doi.org/10.13182/FST89-A25332
Articles are hosted by Taylor and Francis Online.
The results of erosion and redeposition studies of graphite by hydrogen plasma bombardment in the PISCES facility are reviewed. The total erosion yields of several types of graphites have been measured during plasma exposure with ion fluxes of up to 2 × 1018 cm−2·s−1, ion energies of 50 to 200 eV, and sample temperatures of 50 to 950°C. Hydrogen and deuterium plasmas have been used to bombard Poco, ATJ, and pyrolytic graphites, and a “four-directional” carbon-carbon (C-C) composite weave. The erosion rates of all the graphites tested are about equal, suggesting that surface damage by the ion bombardment results in similar erosion yields. The C-C composite weave material showed an increased weight loss during initial exposure, and then equal or lower erosion yields compared to the other graphites. Graphite has a strong ion energy dependence in the maximum chemical erosion yield at a temperature of 500 to 600°C and no energy dependence for the erosion at room temperature. At temperatures above 800°C, the chemical erosion is suppressed and the erosion yield reaches values expected for physical sputtering with thresholds of ∼40 eV for both hydrogen and deuterium. The measured erosion rates demonstrate that chemical sputtering is not significantly suppressed by high-ion fluxes. The net erosion is also reduced by reionization in the plasma and redeposition of hydrocarbons and physically sputtered carbon.