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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.”
Werner Schenk, Heinz Nabielek
Nuclear Technology | Volume 96 | Number 3 | December 1991 | Pages 323-336
Technical Paper | Nuclear Fuel Cycle | doi.org/10.13182/NT96-3-323
Articles are hosted by Taylor and Francis Online.
The essential feature of small, modular high-temperature reactors (HTRs) is the inherent limitation in maximum accident temperature to below 1600°C combined with the ability of coated particle fuel to retain all safety-relevant fission products under these conditions. To demonstrate this ability, spherical fuel elements with modern TRISO particles are irradiated and subjected to heating tests. Even after extended heating times at 1600°C, fission product release does not exceed the already low values projected for normal operating conditions. Details of fission product distribution within spherical fuel elements heated at constant temperatures of 1600, 1700, and 1800°C are presented. The measurements confirm the silicon carbide (SiC) coating layer as the most important fission product barrier up to 1800° C. If the SiC fails (or is defective), the following transport properties at 1600 to 1800°C can be observed: cesium shows the fastest release from the UO2 kernel but is highly sorbed in the buffer layer of the particle and in the matrix graphite of the sphere; strontium is retained strongly both in UO2 kernels and in matrix graphite, but can penetrate SiC in some cases where cesium is still completely retained; only if all coating layers are breached can iodine and noble gases be released. For the first 100 h at 1600°C (enveloping all possible accident scenarios of small HTRs), these fission products are almost completely retained in the coated particles.