Challenge. Conduct characterization and modeling needed for license application and regulatory approval for disposal of Texas Compact and federal LLW.

Solution. INTERA provided geologic, hydrogeologic, and other technical support for several permit and license applications for a hazardous waste disposal and low-level radioactive waste storage and processing facility in Andrews County, Texas. This included the license application to expand operations to include receipt, treatment, and disposal of low-level radioactive waste from both the Texas Compact and other federal agencies. Our characterization efforts focused on evaluating the regional and local geologic and hydrogeologic conditions in the vicinity of the site and included borehole drilling and well/piezometer installation, borehole geophysics, well testing, surface geophysical surveying (seismic and resistivity), surface mapping, excavation structural mapping and analysis, and developing comprehensive geologic and hydrogeologic conceptual models of the area. As part of verifying and refining the conceptual models, we also developed several numerical models to evaluate: 1) the importance of unsaturated zone flow properties on flow and transport characteristics and on the site’s suitability for geologic isolation of radioactive wastes; 2) potential radionuclide releases from the facility; 3) the effects of potential recharge variations; and 4) whether the saturated zone will intersect the landfills. In addition, INTERA interacted with the regulatory agencies, participated in community and stakeholder meetings, and addressed agency comments and requests regarding the license applications. As a result of INTERA’s work, and the efforts of several other Waste Control Specialists’ contractors, the facility was issued the appropriate licenses and became the first in Texas to dispose of LLW and byproduct material.