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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.”
M. V. Speight
Nuclear Science and Engineering | Volume 37 | Number 2 | August 1969 | Pages 180-185
Technical Paper | doi.org/10.13182/NSE69-A20676
Articles are hosted by Taylor and Francis Online.
The influence of intragranular bubbles, acting as efficient trapping sites, on the migration of fission gas atoms in material under irradiation is assessed. It is considered that the bubbles are unstable due to the operation of an irradiation-induced resolution process tending to dissolve their enclosed gas. Treating an individual grain within the material as a sphere whose boundary behaves as a perfect sink, general expressions are derived for the intragranular concentrations of gas existing instantaneously within bubbles and in solution. It is shown that the relationships may be simplified for the range of irradiation times and conditions likely to be encountered in practice. Under these conditions, an expression is obtained for the quantity of gas released to the grain boundary, and this is compared with the analogous expression derived previously by Booth for the case where there are no intragranular traps. The fact that the resolution process through its effects on bubbles at the grain boundary will return some gas to the matrix and in so doing destroy the property of perfect-sink behavior is later considered. By an approximate method the appropriate modification to the formula describing the quantity of gas released to the boundary is deduced. This final expression, including the complete effects of intragranular trapping and irradiation-induced resolution on gas migration, may provide the basis on which to calculate the amount of gas which is eventually released external to the material from regions where intergranular bubbles grow so large that they interlink.