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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.”
Zoltán Perkó, Jan Leen Kloosterman, Sándor Fehér
Nuclear Technology | Volume 177 | Number 1 | January 2012 | Pages 83-97
Technical Paper | Fuel Cycle and Management | doi.org/10.13182/NT12-A13329
Articles are hosted by Taylor and Francis Online.
Within the Generation IV initiative, the gas-cooled fast reactor (GFR) is one of the reactors dedicated to minor actinide (MA) transmutation. This paper summarizes the research performed with the GFR600 reference design in order to assess its MA burning capabilities. For the study, modules of the SCALE program system were used.Single-cycle parametric studies were performed with cores having different MA content and spatial distribution. It was shown that the addition of MAs to the fuel greatly reduced the reactivity loss during burnup. Moreover, the higher the MA content of the core, the higher the fraction of it that was fissioned; however, the more the delayed neutron fraction and the fuel temperature coefficient degraded. Significant reduction can be achieved in the amounts of neptunium and americium, while curium isotopes accumulate.The study of multiple consecutive cycles showed that by adding only depleted uranium (DU) to the reprocessed actinides in fuel fabrication (pure DU feed strategy), up to 70% of the initially loaded MAs can be fissioned in the first five cycles. Moreover, the reactor can be made critical during that time if the initial MA content is higher than 3%. By feeding MAs as well (constant MA content strategy), the reactivity has a steady increase from cycle to cycle, predominantly due to 238Pu breeding from 237Np.The effects of the isotopic composition of the plutonium and MAs were also examined by performing calculations with data specific to the spent fuel of traditional western pressure water reactors and Russian type VVER440 reactors. Despite the considerably different MA vectors, no significant deviation was found in their overall transmutation. However, the Pu composition had a strong effect on the reactivity and the delayed neutron fraction in the first cycles.Finally, cores having nonuniform MA content were investigated. It was found that though the MA destruction efficiency was significantly higher in the middle of the core than at the edge, moving some of the MAs from the outer regions to the center resulted in only minor improvement in their destruction. However, the spectral changes caused by the rearrangement increased the k-effective, which allowed higher burnups and increased MA destruction. Unfortunately, some of the safety parameters of the reactor degraded.