Comparative research on leaching models of radionuclides in cement solidified waste forms

Based on the diffusion mechanism of radionuclide leaching from cement-solidified waste forms, a two-dimension decay leaching model (T-DLM) was established, according to Fick's second law and the initial and boundary conditions. The leaching behavior of 137Cs in the lab-scale alkali-activated slag-clay minerals composite cement and full scale sulfate resistant cement waste forms was predicted using the T-DLM, via correcting its apparent diffusion coefficient. It was compared with the one-dimension leaching model and one-dimension decay leaching model available. The results indicate that the values calculated using the T-DLM are in a better agreement with the experimental values. (authors)