Présentations Colloques

Crystalline rocks are considered as potential host rocks for deep geology repositories (DGR) of radioactive waste in many European countries. The main transport mechanism in the crystalline rock is advection, however migration processes from fracture through fracture coating into unaltered rock has also to be studied. The conceptual model is based on the presumption that non-advective migration is driven by diffusion into both altered mineral layers and undisturbed rock matrix, adjacent to water bearing fissures.**Radionuclide migration from fracture towards granitic rock matrix is studied using laboratory block-scale samples (cm to dm size) and radioactive tracers (3H, 36Cl) within CZ project PAMIRE (TA04020986). The results are implemented into the study of scaling up radionuclide migration processes towards the in-situ experiments in the Josef Underground Laboratory (https- ceg.fsv.cvut.cz en). Simulation codes MODFLOW MT3DMS and NAPSAC NAMMU (continuous porous medium and discrete fracture network models) were used for the evaluation of flow and transport through the granite samples and in the granite host rock. Inverse modelling was utilised in order to calibrate the heterogeneous flow-diffusion macroscopic characteristics - fracture transmissivity, porosity, hydraulic conductivity and effective diffusion coefficient of the fresh and disturbed rock matrix.