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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.”
Younggil Jin, Hyun-Su Kim, Sun-Taek Lim, Jin-Young Lee, Nam-Kyun Kim, Jae-Min Song, Gon-Ho Kim
Fusion Science and Technology | Volume 68 | Number 1 | July 2015 | Pages 113-119
Technical Paper | Open Magnetic Systems 2014 | doi.org/10.13182/FST14-886
Articles are hosted by Taylor and Francis Online.
The effect of interface diffusion between tungsten and graphite on embrittlement has not been examined over the tungsten ductile-brittle transition temperature. To analyze interface embrittlement with tungsten carbide (WC) formation and hardness, a reactive diffusion barrier model was adapted to clarify the roles of leak rate, lag time, and impurity. Plasma-sprayed tungsten (PS-W) on graphite with molybdenum interlayer (diffusion barrier) was fabricated using plasma-spray. The carbon concentration and hardness were measured using energy-dispersive X-ray spectroscopy and micro-indentation after furnace experiments relevant to plasma-facing component upper limit temperature (1470 K). The lag time and the leak rate were determined by the model with different impurity amounts (10-30 at. %) and barrier thicknesses (1-40 μm). It is worth noting that the lag time determines embrittlement threshold time because it delays the onset of diffusion, and it is expanded with thicker barrier and impurity (0.07-21000 ms). The leak rate represents the embrittlement rate since it limits the diffusion flux, and it does not depend on impurity but on barrier thickness. Diffusion-induced interface embrittlement was measured and estimated based on WC fraction. The embrittlement can be spatially expanded with time, suggesting that interface embrittlement can be severe for KSTAR long-term operation.