| Interactions of soil, radionuclides, and water influence the design and implementation of low-level radioactive waste (LLW) disposal facilities. Uniform assessment of containment strategies for LLW is controlled by the need for further understanding of the transport processes affecting the waste itself, particularly the potential for sorption and diffusion of radionuclides through installed containment barriers. Soils high in clay content offer a variety of benefits for lining disposal sites, specifically their natural abundance and availability and typically low hydraulic conductivity. Additionally, clays have been recognized within the literature for their ability to attenuate pollutants, including heavy metals, actinides, and other trace elements. With the reliance on barrier soils to ideally prevent, but more realistically limit, contamination of the environment surrounding LLW disposal facilities, understanding sorption as a solute transport mechanism through these materials is fundamental for improving disposal systems. Of potential further impact are the geochemical aspects that can alter sorption properties of barrier soils, including pH, ionic strength, calcium content, and carbonate content.;Batch experimentation aims to address sorption interactions through the individual study of a single radionuclide and a synthetic radioactive leachate mixture onto a suite of barrier soils and geosynthetic clay liner-derived bentonites with varying mineralogical properties. Four primary batch sorption experiments were run: (1) control experimentation, (2) kinetics, (3) sorption edges/envelopes, and (4) sorption isotherms. The acquired results help to parameterize the relationship between radionuclide sorption, solution characteristics, including pH and ionic strength, and the mineralogical characteristics of the selected soils. The proportionality of radionuclide sorption to the exchange capacity of soils, as a function of the type and magnitude of the minerals within the soil column, is investigated. Inclusion of carbonate species shows a decrease in sorption capacity, while the presence of amorphous iron increases sorption. Cross-comparisons between sorption behavior of purified clays and iron minerals within the literature to the study soils show a reliance on multiple portions of the mineralogic soil content to account for demonstrated radionuclide sorption capacity. |
