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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.”
Hesham R. Nasif, Atsushi Neyama, Hiroyuki Umeki, Atsuyuki Suzuki
Nuclear Technology | Volume 141 | Number 3 | March 2003 | Pages 275-300
Technical Paper | Radioactive Waste Management and Disposal | doi.org/10.13182/NT03-A3367
Articles are hosted by Taylor and Francis Online.
Radionuclides released from a vitrified waste package after overpack failure spread into the buffer material surrounding the waste package, then migrate through different pathways into the water-bearing fracture in the rock surrounding the high-level radioactive waste repository, and transport through the faults to the biosphere. The buffer material has low permeability and the solute is transported through the engineered barrier system by diffusion only. In the water-bearing fracture, the problem is of the convection diffusion type with highly varying parameters from one medium to the other due to the variability in length, transmissivity, and other transport-relevant properties of the transport paths. This complex geometry is modeled using the wavelet Galerkin approach. The Wavelet Integrated Repository System (WIRS) wavelet-based system is an integrated tool to calculate the transport of single or radionuclide chains in both near and far fields of the repository system. The model, which is a very coarsely discretized wavelet based, is devised to be very fast since the scaling functions, which are used as a basis function, are compactly supported. Only finite numbers of the connection coefficients are nonzero, and the resultant matrix has a block diagonal structure that can be inverted easily. One of the main problems encountered in solving the model for the radionuclide transport in the geospheric media is the treatment of the boundary and interface conditions. In order to maintain the integrity of the system, the boundaries of the wavelet series are shifted until the end is independent of any expansion coefficients of the scaling function that affect the solution within the real boundaries. WIRS agreed well with models using a very detailed discretization. Accuracy is gained with the proper selection of wavelet-dilation orders pair. WIRS has been applied to the Japanese high-level radioactive waste repository concept where the migration is through different barriers and pathways. Single and decay chain radionuclide release calculations have shown the capability of WIRS to handle different situations rapidly and easily.
