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ANS Student Conference 2025
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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. dos Santos, H. Pasqualeto, L. C. C. B. Fanaro, R. Fuga, R. Jerez
Nuclear Science and Engineering | Volume 133 | Number 3 | November 1999 | Pages 314-326
Technical Paper | doi.org/10.13182/NSE99-A2091
Articles are hosted by Taylor and Francis Online.
A new experimental quantity is presented to serve as a benchmark to verify the adequacy of the newly released 235U thermal and subthermal cross sections for the determination of the reactivity coefficients of light water reactors. Such a quantity is denominated the inversion point, and by definition it is the temperature for which the isothermal reactivity coefficient of a reactor system becomes positive. The experimental bases for its determination are discussed. The experiment has been performed in the IPEN/MB-01 reactor facility. Instead of heating the reactor system as usual in experiments considering temperature variations, the reactor system is cooled to ~8.5°C. By means of a heating/cooling system, the temperature is allowed to increase slowly in a stepwise manner. For each step, the control bank critical position is recorded, and by analyzing its behavior as a function of temperature, the inversion point is inferred. The inversion point has been found to be an adequate experimental quantity to validate the thermal and subthermal 235U cross section because it does not require any sort of calculated correction factors or any quantity that comes either from the calculational methodologies or from another experiment. In addition, the inversion point is an experimental quantity that can be measured with an excellent level of accuracy due mainly to the very precise characteristics of the control bank system of the IPEN/ MB-01 reactor. The final value obtained for the IPEN/MB-01 reactor is 14.99 ± 0.15°C.
