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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.”
Cheol Ho Pyeon, Takahiro Yagi, Kiichi Sukawa, Yoshimasa Yamaguchi, Tsuyoshi Misawa
Nuclear Science and Engineering | Volume 177 | Number 2 | June 2014 | Pages 156-168
Technical Paper | doi.org/10.13182/NSE13-21
Articles are hosted by Taylor and Francis Online.
Experimental studies on the thorium-loaded accelerator-driven system (ADS) were conducted at the Kyoto University Critical Assembly. Mockup experiments were carried out in both the critical and subcritical states to investigate the influence of different thermal neutron profiles on the thorium capture and fission reactions. Thorium plate irradiation experiments for the thorium capture and fission reactions demonstrate fission reactions in the critical state, and the calculated-to-experiment values of reaction rates show accuracy within a relative difference of ∼30%. In the ADS experiments with an external neutron source (14-MeV neutrons and 100-MeV protons), subcritical experiments were carried out in the thorium-loaded cores to investigate the influence of different thermal neutron profiles on thorium capture reaction rates by the measurement of 115In(n,γ)116mIn reactions. The results reveal the difference between reaction rate distributions attributed to varying not only the neutron spectrum of the core but also the external neutron source. A comparison between the measured and calculated reaction rate distributions reflects the accuracy of reaction-rate analyses for the thorium-loaded ADS experiments with an external neutron source. Additionally, kinetic experiments were carried out to deduce the prompt neutron decay constants and subcriticality by the pulsed neutron method.
