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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.”
Ce Yi, Alireza Haghighat
Nuclear Science and Engineering | Volume 164 | Number 3 | March 2010 | Pages 221-247
Technical Paper | doi.org/10.13182/NSE09-110
Articles are hosted by Taylor and Francis Online.
In this paper, we present a hybrid formulation/algorithm to solve the linear Boltzmann equation, specifically for application to problems containing regions of low scattering. The hybrid approach uses the characteristics method in low scattering regions, while the remaining regions are treated with the discrete ordinates method (SN). A shared scattering kernel allows an arbitrary order of anisotropic scattering in both block-oriented solvers. A new three-dimensional transport code (TITAN) has been developed based on the hybrid approach. TITAN divides a problem model into coarse meshes (blocks) in the Cartesian geometry. The block-oriented structure allows different fine-meshing schemes (or characteristic ray densities) and angular quadrature sets for different coarse meshes. Angular and spatial projection techniques are developed to transfer angular fluxes on the interfaces of the coarse meshes. We have tested the performance and accuracy of the new hybrid algorithm within the TITAN code for a number of benchmark problems. The results of a computed tomography model and the Kobayashi benchmark problems are presented in this paper. It is demonstrated that while preserving high-level accuracy as compared to reference Monte Carlo simulations, the hybrid algorithm achieves significant computation efficiency as compared to the SN method only.
