Natural analogue study on geological disposal of high level nuclear waste --migration behavior of elements during weathering

摘要

For the safety assessment of geological disposal of high level nuclear waste it is essentially important to elucidate the long-term migration behavior of radioactive elements in shallow geologic environment as well as in deep environment. For this purpose in mind, the migration behavior of chemical analogue elements (REEs, U, and Th) during the chemical weathering of several types of rocks and soils (e. g., Andosols, Loam, sedimentary rocks) was investigated. REEs are depleted in Andosols compared with parent volcanic ash. However, they accumulate or do not remove from the Loam underlying the Andosols. REEs migrate significantly in the sedimentary rocks (shale) but they adsorb onto secondary minerals (e.g., iron oxyhydroxides).