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Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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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.”
He Liaoyuan, Xia Shaopeng, Chen Jingen, Liu Guimin, Wu Jianhui, Zou Yang
Nuclear Science and Engineering | Volume 195 | Number 2 | February 2021 | Pages 185-202
Technical Paper | doi.org/10.1080/00295639.2020.1798728
Articles are hosted by Taylor and Francis Online.
The molten chloride salt fast reactor (MCFR) with Th-U fuel cycle is attracting more and more attention because of its excellent performance, such as high solubility of actinides, superior breeding capacity, low waste production, and high inherent safety. First of all, the breeding capability of an MCFR at equilibrium state was optimized by an in-house automated optimization program. Based on an optimized MCFR, an investigation of Th-U cycle performance was performed. Due to the lack of available 233U in nature, transuranium (TRU), low-enriched uranium (LEU), and Pu were employed as the startup fissile materials, and two different transition scenarios, a breeding and burning (B&B) scenario and a pre-breeding and burning (PBB) scenario were studied. The results show that the breeding performance in an MCFR is attractive and that the Th-U fuel transition can be achieved smoothly by using LEU, Pu, or TRU as startup fissile materials. In the B&B scenario, the average net 233U production rate in the LEU-started, TRU-started, and Pu-started modes during 200-year operation is 374, 321, and 323 kg/a, respectively, at the reprocessing rate of 200 L/day. While in the PB&B scenario the average annual 233U production is about 570 kg for all startup cases at a reprocessing rate of 40 L/day, and the corresponding doubling time is about 9.6 years. Besides, the values of the fuel Doppler coefficient and density coefficient are negative, and the total temperature coefficient of reactivity in all scenarios is below −8 pcm/K. In addition, the value of radiotoxicity of the Th-U cycle in an MCFR is lower than that in other molten salt reactors like the molten-salt breeder reactor and the molten fluoride salt reactor due to the lower buildup of fission products and TRU under its hard spectrum.
