COUPLED MODELING OF CEMENT/CLAYSTONE INTERACTIONS AND RADIONUCLIDE MIGRATION

A reactive transport code HYTEC is applied in the case of two-dimensional vertical cross-section of horizontal tunnels analysis with location of cement, waste package and claystone zones. Thermodynamic database is provided for the calculations of radionuclide solubility and sorption. Modelling cement/claystone interactions and mineralogical evolution are discussed Surface complexation, ion exchange and cation exchange processes are estimated. Evolution over a period of 100000 years is computed and profiles of the unreactive tracer concentration and pH for different mineralogical hypotheses are given. Clogging and cement/claystone interface and migration of radionuclides are analysed.