| Abstract: |
Transport of radionuclides that escape failed waste packages (WP) may be significantly affected by interaction with the alteration products derived from the WP components and other construction materials. The interaction of WP’s and other ferrous metal materials with groundwater prior to failure is expected to result in the formation of iron oxides (Viani, 1996). These phases are expected to significantly retard U and Np, radionuclides that are not strongly retarded by the repository horizon and the surrounding rocks (Meijer, 1990). Because sorption of radionuclides onto iron oxides is strongly dependent on fluid composition (e.g.; pH and dissolved carbon), mechanistic models that capture the detailed chemistry and physics that control transport must validated before credible predictions of the effects of WP alteration products can be made, and before limits on radionuclide transport through the engineered barrier system (EBS) can be placed. Reactive transport models that couple sorption models to fluid flow models are also required to assess the ability of more simplistic PA models to capture the essential features of the transport process. This letter report presents results of sorption and transport experiments that are designed to obtain parameters to be used in coupled models and to test the ability of these models to predict transport. |
