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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.”
Kun Jie Yang, Yue-Lin Liu, Ning Liu, Peng Shao, Xu Zhang, Yuming Ma
Fusion Science and Technology | Volume 76 | Number 5 | July 2020 | Pages 616-631
Technical Paper | doi.org/10.1080/15361055.2020.1740556
Articles are hosted by Taylor and Francis Online.
We performed systematically first-principles calculations to investigate interstitial H diffusion/permeation of temperature dependence in tungsten (W). The interstitial H diffusion is primarily through two nearest-neighbor tetrahedral positions and its activation energy increases significantly with rising temperature. Phonon vibration plays a decisive role in the behavior of the H activation energy with rising temperature. The H permeation activation energy also depends strongly on the temperature since it is the sum of the formation energy and diffusion activation energy of H. Our calculated H diffusivity/permeability with the temperature agree quantitatively with the reliable experimental data within the error range in W. The vacancy-capturing effect can give a reasonable explanation of the discrepancy between simulation and experiment. Although the diffusion/permeation activation energy and the prefactor strongly depend on the temperature, the diffusivity/permeability of H still obeys quasi-Arrhenius behavior with rising temperature, which is attributed to the compensation effect between the activation energy and the prefactor, i.e., the increment of the prefactor compensates directly the modification of the diffusivity/permeability in the case of a variation in the activation energy with rising temperature.