Most of the highly radioactive spent nuclear fuel (SNF) around the world is destined for final disposal in deep-mined geological repositories. At the end of the fuel's useful life in a reactor, about 96% of the SNF is still UO. Thus, the behaviour of UO in SNF must be understood and evaluated under the weathering conditions of geologic disposal, which extend to periods of hundreds of thousands of years.
View Article and Find Full Text PDFLong-term performance assessment of nuclear waste repositories is affected by the ability of the outer barrier systems to retain radionuclides after possible corrosive leakage of waste containers. The mobility of the radionuclides released from the spent fuel depends strongly on the processes that take place in the backfill material. The interaction of steel corrosion products and radionuclides is part of such a scenario.
View Article and Find Full Text PDFIn the high level nuclear waste repository concept, spent nuclear fuel is designed to be encapsulated in steel canisters. Thus, it is necessary to study the influence of the steel and/or its corrosion products on the behaviour of the radionuclides released from the fuel. In this sense, the main objective of this work is to contribute to the knowledge of the influence of the steel and/or its corrosion products on the uranium(VI) retention.
View Article and Find Full Text PDFThe processes that affect the mobility of uranium and other radionuclides in the environment have been largely studied at both the laboratory and the field scales. The natural reactors found at the Oklo uranium mine in Gabon constitute a unique investigation setting as spontaneous fission reactions occurred two billion years ago. Oklo uraninites contain a large amount of other radionuclides as a result of the fission process.
View Article and Find Full Text PDFThe aim of this work is to demonstrate that theoretical chemistry can be used as a complementary tool in determining geometric parameters of a number of uranyl complexes in solution, which are not observable by experimental methods. In addition, we propose plausible structures with partial geometric data from experimental results. A gradient corrected DFT methodology with relativistic effects is used employing a COSMO solvation model.
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