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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.”
Eric Leclerc, Georges J. Berthoud
Nuclear Technology | Volume 144 | Number 2 | November 2003 | Pages 158-174
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT03-A3437
Articles are hosted by Taylor and Francis Online.
In hypothetical Severe Accident studies for a PWR, a large amount of molten corium may be poured into water. There is then a risk of Steam Explosion. After the premixing sequence in which the melt is more or less dispersed into water, a fine fragmentation process may start, which can lead to an escalation. Such an event is generally triggered by the destabilization of the vapor film surrounding the hot melt droplets. In this paper, an attempt to describe all the successive processes leading to this fine fragmentation is presented.First, a critical analysis of previous models is performed, allowing us to propose a new sequence of events. As in the previous models, the film destabilization leads to the growth of cold liquid peaks induced by Rayleigh Taylor instability. As these peaks have a smaller density than the drop, they do not penetrate into the hot drop. At the cold liquid-hot liquid contacts, transient heat transfer leads to the explosive boiling of a small amount of coolant. The generated local pressurization deforms the hot melt interface. This can produce fine fragments from the filaments issued from the melt. Some of them may reach the vapor-coolant interface where intense and rapid vaporization occurs. A large bubble then develops, and a new fragmentation sequence may again appear at the bubble collapse. The present model is supported by experimental results.