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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.”
Christopher M. Perfetti, Bradley T. Rearden, William R. Martin
Nuclear Science and Engineering | Volume 182 | Number 3 | March 2016 | Pages 332-353
Technical Paper | doi.org/10.13182/NSE15-12
Articles are hosted by Taylor and Francis Online.
The need to model geometrically complex systems with improved ease of use and fidelity and the desire to extend the Tools for Sensitivity and UNcertainty Analysis Methodology Implementation (TSUNAMI) analysis to advanced applications have motivated the development of a methodology for calculating sensitivity coefficients in continuous-energy (CE) Monte Carlo applications. The Contributon-Linked eigenvalue sensitivity/Uncertainty estimation via Track length importance CHaracterization (CLUTCH) and Iterated Fission Probability (IFP) eigenvalue sensitivity methods were recently implemented in the CE KENO framework of the SCALE code system to enable TSUNAMI-3D to perform eigenvalue sensitivity calculations using CE Monte Carlo methods. This paper provides a detailed description of the theory behind the CLUTCH method and describes in detail its implementation. This work also explores the improvements in eigenvalue sensitivity coefficient accuracy that can be gained through use of CE sensitivity methods and compares several sensitivity methods in terms of computational efficiency and memory requirements. The IFP and CLUTCH methods produced sensitivity coefficient estimates that matched, and in some cases exceeded, the accuracy of those produced using the multigroup TSUNAMI-3D approach. The CLUTCH method was found to calculate sensitivity coefficients with the highest degree of efficiency and the lowest computational memory footprint for the problems examined.