Volumetric and radiological capacity requirements for disposal of treated mixed low-level waste

Abstract

The U.S. Department of Energy (DOE) has stored or expects to generate over the next five years more than 130,000 m 3 of mixed low-level waste (MLLW). Before disposal, MLLW is usually treated to comply with the land disposal restrictions of the Resource Conservation and Recovery Act. Depending on treatment type, the volumes and radionuclide concentrations of the waste streams may change. These changes must be taken into account in determining necessary disposal capacity at a site. Treatment may remove the characteristic feature that caused classification as mixed waste. Treatment may also, by reduction of mass, increase the concentrations of transuranic radionuclides sufficiently so that some waste becomes transuranic waste. This paper describes an analysis of the DOE MLLW streams to determine treated volumes and radionuclide concentrations. The waste streams were reclassified as residual MLLW, or low-level or transuranic waste resulting from treatment. About 89,000 m 3 of waste was identified for disposal as residual MLLW. Fifteen DOE sites were evaluated to determine their capabilities for hosting disposal facilities for residual MLLW. Waste streams associated with about 90% of the residual MLLW volume are likely to present no significant issues for disposal. Future studies should focus on the remaining waste streams that are potentially problematic by examining site-specific waste acceptance criteria, alternative treatment processes, alternative waste forms for disposal, and pending changes in regulatory requirements.