Effective diffusivity of neptunium and plutonium in granite from Inada, Ibaraki, Japan under anaerobic conditions

Abstract

SummaryThe effective diffusivities of neptunium and plutonium in Inada granite have been determined using the through–diffusion method. Experiments were performed under anaerobic conditions in the presence of carbonate. The actinides are expected to be present as carbonato or carbonatohydroxo complexes. Effective diffusivity (De) obtained were (4.0 ± 1.5) × 10−13m2s−1for neptunium and (2.0 ± 1.6) × 10−13m2s−1for plutonium. Effective diffusivities of neptunium and plutonium in granite were estimated based on the pore diffusion model and compared with the experimentally obtained values.