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ANS Student Conference 2025
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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.”
Keigo Mio, Tetsuo Kurashige, Toshiso Kosako
Nuclear Technology | Volume 136 | Number 1 | October 2001 | Pages 63-75
Technical Paper | Radiation Protection | doi.org/10.13182/NT01-A3229
Articles are hosted by Taylor and Francis Online.
The shielding effect for neutrons and gamma rays provided by a louver-type steel structure inserted into the second leg of a concrete duct was measured and analyzed. The louver is an assembly of steel plates that are stacked at the same interval to reduce the radiation streaming while keeping air flowing through the duct. The experiment was carried out at the Japan Research Reactor-4 (JRR4) using a large concrete duct that was temporarily installed for this experiment.Experimental data for the shielding effect of the louver were obtained through the use of thermoluminescent dosimeters (CaSO4 and BeO) and an ionization chamber for the gamma dose. A rem counter was used to obtain neutron dose, while a solid-state track detector was used for fast neutron dose. Finally, indium activation foil was used to obtain the thermal neutron flux. A NaI(Tl) scintillation spectrometer was used for the measurement of gamma rays from activated foil.The measured data were compared to that derived from numerical analyses. Numerical analyses included the use of the conventional Sn transport code DOT3.5, the Monte Carlo code MCNP4A, and calculations with empirical formulas.MCNP4A provided satisfactory estimates for all cases. If proper calculations were carried out, then DOT3.5 provided acceptable estimates except for the thermal neutrons in spite of the limitations of the code's two-dimensional geometrical modeling. Calculations by hand using simple empirical formulas with modifications, like that for the angular flux correction, also could provide fairly accurate estimates.