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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.”
D. F. Hollenbach
Nuclear Science and Engineering | Volume 179 | Number 3 | March 2015 | Pages 342-351
Technical Note | doi.org/10.13182/NSE13-46
Articles are hosted by Taylor and Francis Online.
More than 50 years ago it was postulated that a naturally occurring nuclear reactor was possible if it started 2 billion years ago. The subsequent discovery of the natural reactor at Oklo confirmed that it is possible for a nuclear fission reactor to naturally form and cycle on and off over extended periods of time. The hypothesis of a naturally occurring reactor was extended to include the possibility of significant quantities of uranium aggregating inside the molten core of Earth due to gravity during its formation. When sufficient quantities of uranium accumulate, a self-sustaining fission reactor could form, which would fluctuate in power as uranium fissions and fission products are produced. Lighter elements would migrate out of the reactor region, and heavier elements would coalesce due to gravity. In this technical note, SCALE, a state-of-the-art nuclear engineering computer code system developed at Oak Ridge National Laboratory, was used to investigate this hypothesis. The analysis indicates that the overall operational parameters of a postulated nuclear fission reactor located in the inner core of Earth must fall within a relatively narrow band in order to still be operating today. If the overall power level were too low, the reactor would not breed sufficient fissile material, and the average enrichment would drop below the level required to form a self-sustained fast reactor. If the power level were too high, the reactor would have burned itself out well before the present day. The objective of this technical note is to provide calculations that support an existing geo-reactor and the operating parameters that would govern a deep-Earth reactor and allow it to still be operating today, 4.5 billion years after Earth was formed. To help bound the possible power range, a simplified, one-dimensional, homogeneous, deep-Earth reactor having a steady-state fission power is simulated over geologic time. Power levels and start times are varied. The simulations show that if the reactor were still operating today, it would have an overall lifetime average operating fission power of <3 TW. Analyses show that both instantaneous and cumulative 3He/4He ratios are a function of fission power, 235U/238U ratio, total uranium mass, and geo-reactor starting time. The calculated 3He/4He ratios are consistent with those observed in nature.