United States 		Environmental Protection Agency

U.S. EPA Mixed Waste Team

An Overview of Mixed Waste

Mixed waste contains radioactive and hazardous waste. A dual regulatory framework exists for mixed waste, with the U.S. Environmental Protection Agency (EPA) or authorized states regulating the hazardous waste and the U.S. Nuclear Regulatory Commission (NRC), NRC agreement states, or the U.S. Department of Energy (DOE) regulating the radioactive waste. NRC generally regulates commercial and non-DOE federal facilities. DOE is currently self-regulating and its orders apply to DOE sites and contractors. The DOE Advisory Committee on External Regulation recently published its final report titled, "Improving Regulation of Safety at DOE Nuclear Facilities (12/95)." This report debates whether and how DOE facilities may come under external regulation.

Using the Atomic Energy Act (AEA) authority, NRC and DOE regulate mixed waste with regard to radiation safety. Using the Resource, Conservation, and Recovery Act (RCRA) authority, EPA regulates mixed waste with regard to hazardous waste safety. NRC is authorized by the AEA to issue licenses to commercial users of radioactive materials. RCRA gives EPA the authority to control hazardous waste from "cradle-to-grave." Once a waste is determined to be a mixed waste, the waste handlers must comply with both AEA and RCRA statutes and regulations. The requirements of RCRA and AEA are generally consistent and compatible. However, the provisions in Section 1006(a) of RCRA allow the AEA to take precedence in the event provisions of requirements of the two acts are found to be inconsistent.

Graphics showing sources of Commercial Mixed Waste

Almost all of the commercially generated (non-DOE) mixed waste is composed of Low-Level Radioactive Waste (LLRW) and Hazardous Waste and is called Low Level Mixed Waste (LLMW). Commercially generated LLMW is produced in all 50 states at industrial, hospital, and nuclear power plant facilities. Radioactive and hazardous materials are used in a number of processes such as medical diagnostic testing and research, pharmaceutical and biotechnology development, pesticide research, as well as nuclear power plant operations. Based on the results of a survey conducted by NRC & EPA (NUREG/CR-5938), approximately 4,000 m3 of LLMW were generated in the U.S. in 1990. Of this amount, approximately 2840 m3 (or 71%) was liquid scintillation cocktail (LSC). Organic solvents such as chlorofluorocarbons (CFC's), corrosive organics, and waste oil made up 18%, toxic metals made up 3%, and "Other" waste made up the remaining 8%.

Under the 1984 Amendments to RCRA, Land Disposal Restriction (LDR) regulations prohibit disposal of most mixed waste including LLMW until it meets specific treatment standards. While most of the commercial mixed waste that is generated and stored can be treated to meet the LDR's by commercially available treatment technology, there still exists a small percentage of commercial mixed waste for which no treatment or disposal capacity is available. Commercial mixed waste volumes are very small (approximately 2%) compared to the total volume of mixed waste being generated or stored by DOE.

There are three main types of mixed waste being produced or stored at DOE facilities, Low-Level, High Level, and Transuranic.

DOE Low-Level Mixed Waste (LLMW) is generated, projected to be generated, or stored, at 37 DOE sites in 22 states as a result of research, development, and production of nuclear weapons. Waste management activities will require management of an estimated 226,000 m3 of LLMW over the next 20 years.

DOE High Level Waste (HLW) is radioactive waste resulting from reprocessing spent nuclear fuel and irradiated targets from reactors and is liquid before it is treated. Some of its elements will remain radioactive for thousands of years. HLW is also a mixed waste because it has highly corrosive components or has organics or heavy metals that are regulated under RCRA. DOE has about 399,000 m3 of HLW stored in large tanks at four locations: Hanford, Washington; Idaho National Engineering Laboratories (INEL), Idaho; Savannah River Site (SRS), South Carolina; and the West Valley Demonstration Project, New York. DOE is proceeding with plans to treat HLW by processing it into a solid form (e.g. borosilicate glass) that would not be readily dispersable into the air or leachate into the ground or surface water. This treatment process is called vitrification. The vitrification process will generate approximately 29,000 canisters to be disposed of in a geologic repository. Currently Yucca Mountain, Nevada, is being characterized as a potential geological repository. Check out EPA's Yucca Mountain Information HomePage for more information.

DOE Mixed Transuranic Waste (MTRU) is waste that has a hazardous component and radioactive elements heavier than Uranium. The radioactivity in the MTRU must be greater than 100 nCi/g and co-mingled with RCRA hazardous constituents. The principle hazard from MTRU is alpha-particle radiation through inhalation or ingestion. MTRU is primarily generated from nuclear weapons fabrication, Plutonium bearing reactor fuel fabrication, and spent fuel reprocessing. The percentage of non-DOE MTRU is negligible. Approximately 55% of DOE's TRU waste is MTRU. MTRU is currently being treated and stored at six DOE sites: Hanford, (3,000 m3); INEL (38,000 m3); Los Alamos National Laboratories, New Mexico (8,000 m3); Rocky Flats, Colorado (1,500 m3); Oak Ridge National Laboratories, Tennessee (1,500 m3); SRS (5,000 m3). DOE plans to dispose of MTRU at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico. Before DOE can dispose of waste at the WIPP, it must demonstrate that the WIPP complies with EPA's radioactive waste disposal standards. DOE must submit a "compliance application" to EPA showing how the WIPP facility will meet these radioactive waste disposal standards. DOE has submitted a petition to EPA's Office of Solid Waste (which administers RCRA regulations) for a "no-migration" variance for the WIPP MTRU. A "no-migration" variance is granted when the hazardous waste is found to be permanently isolated from the environment for as long as the waste remains hazardous waste. The WIPP facility is scheduled to begin operation in the Spring of 1998, subject to EPA approval of DOE's compliance application.

In DOE's 1995 Baseline Environmental Management Report it roughly estimates that the life-cycle costs for HLW, TRU (including MTRU), and LLMW are $34 billion, $13 billion, and $13 billion respectively over a 75 year period. " Closing the circle on the splitting of the Atom" is another DOE report on the environmental legacy of nuclear weapons production in the United States.

As mandated by the Federal Facilities Compliance Act (FFCA), which was signed into law in October 6, 1992, DOE has developed Site Treatment Plans to handle its mixed wastes under the review of EPA or its authorized States. These are being implemented by orders issued by EPA or the State regulatory authority. DOE is also developing a Waste Management Programmatic Environmental Impact Statement (WM PEIS) for managing treatment, storage, and disposal of radioactive and hazardous waste. This plan will provide environmental input for DOE's proposed action of identifying future configurations for selecting waste management facilities. It will take the cooperation of DOE, EPA, NRC, and the States to address this legacy of the cold war. Proposed DOE Treatment Options are available from the following DOE INEL server.

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URL: http://www.epa.gov/radiation/mixed-waste/mw_pg3.htm

Last Updated: February 6, 1998