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The Mission of the Robotics and Remote Systems Division is to promote the development and application of immersive simulation, robotics, and remote systems for hazardous environments for the purpose of reducing hazardous exposure to individuals, reducing environmental hazards and reducing the cost of performing work.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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.”
Nathan Lafferty, Victor Ransom, Martin Lopez De Bertodano
Nuclear Technology | Volume 169 | Number 1 | January 2010 | Pages 34-49
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT169-3
Articles are hosted by Taylor and Francis Online.
The capability of RELAP5 to model single- and two-phase acoustic wave propagation is demonstrated with the use of fine temporal and spatial discretizations. Two cases were considered: a single-phase air shock tube problem that was simulated, resulting in a shock wave and a rarefaction wave that lie within 1% error of the analytic solution, and pressure oscillations observed by Takeda and Toda in a two-phase decompression experiment in a pipe under a temperature gradient.Whereas the agreement for the single-phase case is excellent, some discrepancies were observed in the two-phase case:1. Thermal nonequilibrium and the associated delay in the bubble growth were identified as the cause for the dispersion of the rarefaction wave as it becomes trapped inside a two-phase fluid region. The short timescale of the experiment justifies the use of a bubble diameter that is one order of magnitude smaller than the standard RELAP5 predicted bubble diameter, which is calibrated for longer transients.2. The initial depressurization undershoots seen in the Takeda and Toda experiment were overpredicted by the RELAP5 model. Improved agreement with the experiment was obtained by altering the discharge coefficient in the choked flow model to account for uncertainties in the discharge geometry and/or the choked flow model at low pressure.By adjusting these parameters RELAP5 produced markedly better comparisons with the experimental data. These results illustrate two generic shortcomings of nuclear reactor system codes, i.e., the absence of a dynamic model for the interfacial area concentration and uncertainty in two-phase choked flow modeling. However, it is remarkable that RELAP5 could predict the complex dynamics of the two-phase acoustic phenomena in the Takeda and Toda experiment in spite of these shortcomings.