EXPERIMENTAL AND SIMULATION INVESTIGATION OF RADIONUCLIDE MIGRATION IN FRACTURED GRANITE

Studying radionuclide migration in fractured granite has direct applications in high-level radioactive waste disposal. This paper presents our recent work on uranium and thorium migration in fractured granite using both experimental and numerical modeling. We estimated parameters for radionuclide dispersion, diffusion, and sorption processes by solving the inverse problem of multicomponent reactive solute transport. This was performed by minimizing a generalized least squares criterion by means of a global optimization algorithm. Concentration data were simultaneously integrated into our numerical framework to identify uranium and thorium transport processes in granite. Addionally, we performed numerical simulations for uranium and thorium migration in the BeiShan fractured granite using parameters obtained from the column-scale experiments. We believe our results provide valuable insights in understanding radionuclide transport in the fractured granite systems.

Keywords：Inverse modeling；Solute transport parameters；Granite；Uranium and thorium