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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.”
Leonhard Meyer, Mireia G. Gargallo
Nuclear Technology | Volume 141 | Number 3 | March 2003 | Pages 257-274
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT03-A3366
Articles are hosted by Taylor and Francis Online.
Experiments were performed in a scaled annular cavity design, to investigate melt dispersal from the reactor pit when the reactor pressure vessel (RPV) lower head fails at low system pressure of less than 2 MPa. The fluid dynamics of the dispersion process was studied using model fluids, water, or bismuth alloy instead of corium, and nitrogen or helium instead of steam. The effects of different breach sizes and locations and different failure pressures on the dispersion were studied, specifically by testing central holes, lateral holes, horizontal rips, and complete unzipping of the bottom head.With holes at the base of the bottom head, the most important parameters governing the dispersion of melt are the hole size and the burst pressure. The fraction dispersed into the reactor compartments increases with larger holes and higher pressures. Values up to 76% have been found for both melt simulant liquids, water, and metal. With lateral breaches the liquid height in the lower head relative to the upper and lower edge of the breach is an additional parameter for the dispersion process, and usually not all the liquid is discharged out of the RPV. The liquid fraction entrained out of the RPV can be higher with a small breach than with a large one because of the longer blowdown time. With lateral failures, maximum dispersed fractions of 50% were found with water as melt simulant and less than 1% with liquid metal. It follows from similarity considerations that the results from the liquid metal tests represent the lower bound for the dispersed melt fractions; however, they are probably closer to the expected values than the results from the water tests, which represent the upper bound. So, significantly less dispersion of melt can be expected for lateral breaches at pressures below 2 MPa, probably less than 10%. If higher dispersion occurs, due to higher pressure at failure or with failures near the bottom center, simple devices to reduce the dispersion out of the cavity may be feasible.