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This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
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ANS Student Conference 2025
April 3–5, 2025
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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.”
Ethwart Pollmann, Joachim Schulze, Dieter Kreuter
Nuclear Technology | Volume 108 | Number 3 | December 1994 | Pages 350-360
Technical Paper | Nuclear Reactor Safety | doi.org/10.13182/NT94-A35017
Articles are hosted by Taylor and Francis Online.
In a boiling water reactor, nuclear-thermal-hydraulic instabilities can occur if extreme operating conditions prevail. In various nuclear reactors, stability measurements have been carried out during which the location and the shape of the stability threshold was measured at a certain exposure point during the cycle. Earlier sensitivity studies have already shown that fuel assembly parameters have only a small influence on stability compared with plant parameters. The influence of plant parameters has been verified by measurements that were carried out in the German boiling water reactor Würgassen every 4 to 6 weeks during cycle 14. The results of the measurements showed for the single-loop operation point (least stable point in the core map) a strong variation of the stability threshold power during the cycle. From the beginning of cycle to the middle of cycle, the stability threshold power decreases by ∼16% (relative). After the minimum was reached, the stability threshold power increased again. Smaller variations of the stability threshold power in the core map at natural circulation indicate that not only the stability threshold varies during the cycle, but also the shape of the stability threshold is changed. Analyses with the code system STAIF have shown that the stability behavior during the cycle can clearly be correlated with the variation of the axial and radial power density profile due to control rod maneuvering and fuel burnup. Furthermore, it could be shown that for the estimation of the neutronic feedback not only the density coefficient must be taken into account but also the void variation caused by a power perturbation.