Special Analysis: Update of Disposal of Cement-Stabilized Encapsulated Waste at the E-Area Low-Level Waste Facility

Abstract

This Special Analysis for Components-in-Grout (CIG) expands the list of isotopes to the full suite of normal isotopes. This revision also addresses selected isotopes in special waste forms from the K and L basin resin that have waste-specific Kds and high-concentration I-129 wastes with waste-specific Kds, including Effluent Treatment Facility (ETF) activated carbon vessels. The full suite of normal isotopes was first screened using the Slit Trench screening results as a conservative approach. The isotopes that survived the screening were analyzed to determine the appropriate CIG inventory limits. The groundwater modeling was revised to incorporate improvements and changes in other recent Special Analyses and Unreviewed Disposal Question (UDQ) evaluations. The air pathway analysis was modified to consider a distributed source rather than a point source. These changes are discussed below in intruder and groundwater sections. Tables and figures are provided in appendices that are directly related to the most recent analyses. Changes to inventory limits are shown in Table 7. Inventory limits for solubility- limited radionuclides require special treatment as discussed in Section 3.1.1.3. U-238 and Pu-239 were analyzed as being solubility-limited, because otherwise they would consume excessive amounts of their inventory limits. Other U and Pu isotopes were notmore » analyzed as being solubility- limited because they would not consume excessive amounts of inventory limits. Current and projected inventories for the K and L basin resins are compared against inventory limits for a single set of 5 CIG trenches. Projections for the K and L basin waste are through 2035, thus actual inventory consumption is dependent on the total number of CIG trenches excavated and filled through 2035. Current inventory for three ETF activated carbon vessels awaiting disposal are compared against inventory limits for a single set of 5 CIG trenches.« less