Published online by Cambridge University Press: 26 February 2011
Diffusion coefficients were measured (Dm) for Pu(IV) in dense mixtures of bentonite and sand (soil) saturated with a synthetic groundwater solution (SGW) at a pH of 8 and at 25°C. The Dm values were approximately 10-14 m2/s. The clay content of the soil, in the range of 10 to 50%, did not have a significant effect on Dm. The Dm values were also compared with diffusion coefficients calculated (Dc) from a model based on a distribution coefficient. Fair agreement between Dm and Dc for Pu(IV) was found for the soils and SGW examined here. It is unlikelv. however, that the model will accurately estimate Dm for Pu, which has a complex solution and sorption chemistry, over a wide range of conditions.