FIELD AND LABORATORY TRANSPORT STUDIES FOR THE YMP AT LOS ALAMOS NATIONAL LABORATORY
Laboratory radionuclide batch sorption and column transport experiments have been conducted using representative samples of alluvium along the projected flow pathway(s) from the proposed repository. Unlike previous sorption experiments, which focused primarily on determining partition coefficients (Kd values), these experiments placed greater emphasis on determining the desorption behavior of the radionuclides. Multi-step desorption experiments (repeatedly introducing fresh water to try to induce desorption) and long-duration column experiments were designed to determine distributions of desorption rate constants and to estimate fractions of irreversibly sorbed radionuclides.
Finally, column transport experiments have been conducted using Pu (initially Pu(V) in solution) sorbed onto natural colloids collected from the saturated alluvium at the ATC. Results show that colloids smaller than about 200-nm may play a major role in enhancing Pu transport. To our knowledge, these experiments represent the first colloid-facilitated Pu transport experiments conducted using natural colloids, natural water, and natural porous media.