In situ experiments on matrix diffusion in fractured crystalline rock

摘要

Migration of contaminants from a fracture into a granitic rock matrix is studied on a unique selection of rock samples using β/γ-autoradiography, γ-spectrometry and LA-ICP-MS. The rock material originates from an in situ dipole experiment where a cocktail of different radionuclides was injected into a shear zone. The resulting concentration profiles of 137Cs, 235U and 237Np in the rock matrix indicate that these nuclides migrated from the fracture at least 1 cm into the granitic matrix over the experimental time scales of 60 days to 3 years.