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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.”
L. Trotignon, P. Thouvenot, I. Munier, B. Cochepin, E. Piault, E. Treille, X. Bourbon, S. Mimid
Nuclear Technology | Volume 174 | Number 3 | June 2011 | Pages 424-437
Technical Paper | TOUGH2 Symposium / Radioactive Waste Management and Disposal | doi.org/10.13182/NT11-A11750
Articles are hosted by Taylor and Francis Online.
Simulations of atmospheric carbonation of concrete intermediate-low level waste cell components were conducted to evaluate potential chemical degradations affecting these components during the operating period of a radioactive waste repository in a deep Callovo-Oxfordian clay layer. Two-phase liquid water-air flow is combined with gas components diffusion processes, leading to a progressive drying of the concrete and an array of chemical reactions affecting the cement paste. The carbonation process depends strongly on the progression of the drying front inside the concrete, which in turn is sensitive to the initial water saturation and to nonlinear effects associated with permeability and tortuosity phenomenological laws.Results obtained with a modified version of ToughReact-EOS4 to represent realistic tortuosity evolution of materials with clogging and saturation are presented and commented upon. Strong porosity clogging of the carbonated concrete is not observed in the simulations; slight porosity opening is in general predicted, except for high initial liquid saturation of the concrete, in which case a moderate porosity reduction is found. Carbonation depths on the order of 0.6 to 1.1 × 10-3 myr-1 are predicted for cementitious components. However, these values are probably overestimations both in depth and intensity of carbonation. The model of cement drying needs some revision to correctly weight diffusion control in the discretized representation of the cement/air boundary. Also, the kinetic model of mineral reactivity needs improvements with respect to the influence of liquid saturation on reaction rates, which are actually strongly decreased in dry materials, and with respect to the protective effect of secondary carbonates.