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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. Abdelghafar Galahom
Nuclear Science and Engineering | Volume 193 | Number 6 | June 2019 | Pages 638-651
Technical Paper | doi.org/10.1080/00295639.2018.1560757
Articles are hosted by Taylor and Francis Online.
This work presents a comparison between the homogeneous and heterogeneous [seed-blanket (SB)] fuel assembly used in the VVER-1200 core. The MCNPX 2.7 code with the ENDF/B-VII.0 data library was used to investigate the possible advantages that can be achieved when the SB assembly is used instead of homogeneous assembly. Thorium-232 was used as a fertile material in the blanket region and different fissile materials were investigated in the seed region. The neutronic characteristics of the presented designs were investigated by comparing four different combinations of fissile materials with (Th,U)O2 that were distributed uniformly through the whole assembly. The radial power distribution was investigated in both homogeneous and SB assemblies. The power distribution is flatter in the homogeneous assembly than the heterogeneous assembly. The suggested fuels in the SB assembly achieved a longer fuel cycle than the homogeneous assembly. Neutronic parameters related to reactor safety operation, such as control rod worth, Doppler reactivity coefficient, and effective delayed neutron fraction βeff have been investigated for the suggested fuel types. The SB assembly achieved a higher conversion ratio than the homogeneous assembly. Therefore, the fissile inventory ratio decreased more slowly with burnup in the case of SB than in the homogeneous assembly. Using 232Th instead of 238U reduced the production of the plutonium and the transuranic atoms.
