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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.”
L. Eric Smith, Naeem M. Abdurrahman
Nuclear Technology | Volume 140 | Number 3 | December 2002 | Pages 328-349
Technical Paper | Radiation Measurements and Instrumentation | doi.org/10.13182/NT02-A3343
Articles are hosted by Taylor and Francis Online.
A Monte Carlo study of the neutron slowing-down spectrometry technique for measuring fissile isotopic content in irradiated fuel has been completed. The neutron spectrometer system is characterized in terms of design, slowing-down time relation, isotopic response functions, and assay signals. The nonlinear effect of interrogating neutron self-shielding for a high fissile content fuel is compared to the same parameter for a low fissile content fuel. Simulated assays of 23 different fuel assemblies with a broad range of total fissile mass content (1.3 to 83 wt%) and fissile isotopic ratios are performed and analyzed using two different methods: a linear system model using a least-squares regression analysis and a radial basis neural network. Mean errors using the linear system model for the 23 different fuel types were approximately 20% for 235U and 43% for total plutonium. The radial basis neural network assay signal solutions showed promising results, considerably better than the linear model: 4.9% for 235U, 5.4% for total plutonium, and 0.5% for total fissile content.
