Diffusion and Sorption Properties of Some Sorbing Nuclides onto Granodiorite in a Modified Through-Diffusion Setup

Through-diffusion experiments of some sorbing nuclides onto granodiorite have been carried out to understand their diffusion and sorption characteristics. A newly designed experimental setup with compacted structure and dimensions was used for the through-diffusion process. The nuclides used in the experiment were tritiated water (HTO), Sr, Cs, Ni, Nb, and Am. The diffused nuclides were sampled at certain periods of time to estimate the diffusivities. After the diffusion experiment was carried out for 1.5 years, the rock media were recovered. In addition, a sequential chemical extraction was conducted to estimate the sorption types of the nuclides for the recovered rock disks. The relationship between diffusion and sorption was investigated from the viewpoint of sorption reversibility. The measured diffusivity was compared to the other experimental results.