The State of Development of Waste Forms for Mixed Wastes

More than 167,000 m of mixed waste, waste that contains both chemically hazardous and radioactive components, are in the known inventory at DOE sites that formarly produced nuclear defense materials. The inventory contains both mixed low level wastes (MLLW) and mixed transuranic wastes (MTRU). Site cleanup and decommissioning activities during the coming years are expected to nearly double this inventory. At the request of the DOE Assistant Secretary for Environmental Management (EM), the National Research Council’s Board on Radioactive Waste Management (BRWM) appointed a Committee on Radioactive Mixed Wastes which issued its final report in June 1999. The main task of the committee was to review and evaluate the state of development of the final waste forms of treated mixed wastes as they arise from current and emerging treatment technologies. In particular, the study assessed the characteristics of, and uncertainties associated with, the different kinds of waste forms, and identified needs for additional R&D. The Committee’s general finding is that the currently available waste forms are sufficiently developed to meet regulatory requirements for disposal of DOE’s known and expected mixed waste inventory. No single form is appropriate for all wastes, but collectively the available waste forms and well established waste treatment technologies make it unlikely that a totally new class of waste forms will be necessary to complete EM’s planned cleanup programme.