The final step in the waste management process is waste disposal, the permanent isolation of waste. Some wastes can be managed and disposed safely with existing facilities and proven methods. Other Department of Energy (DOE) wastes require more complex disposal facilities. DOE has conducted extensive research into alternative waste disposal methods and has concluded that deep geologic disposal is the best method to dispose of the most radioactive waste. Geologic disposal is the permanent burial of radioactive waste in a stable, deep, rock formation. The disposal areas, or repositories, will be designed to contain and isolate high-level and transuranic radioactive waste. A combination of natural features and man-made components will be used to create a series of barriers to prevent the release of radionuclides into the surrounding environment.
Where Are The Disposal Sites?
In 1987, Congress directed DOE to study Yucca Mountain, Nevada, to determine whether it is a suitable location for the Nation's first deep geologic repository for high-level waste. The Yucca Mountain site, which is near the Nevada Test Site, is far from large population centers, has a very dry climate, and has an extremely deep water table. Scientists are studying Yucca Mountain's geology and environment, and a number of social, transportation, and economic issues. These studies will enable DOE and its regulators to evaluate Yucca Mountain's suitability as a disposal site for high-level waste.
Yucca Mountain in Nevada is being characterized to determine its suitability for a deep geologic repository for the permanent disposal of high-level waste. Above is a drawing of the proposed repository.
The Waste Isolation Pilot Plant (WIPP) was authorized by Congress in 1979 as the Nation's first research and development facility to demonstrate the safe geologic disposal of transuranic waste. Located near Carlsbad, New Mexico, the WIPP repository was constructed 2,150 feet below the surface facilities in a salt formation. The WIPP Land Withdrawal Act of 1992 established a regulatory framework within which DOE must demonstrate compliance with the Environmental Protection Agency's disposal regulations. As a result of provisions contained in the Fiscal Year 1997 Defense Authorization Act, DOE could begin disposal operations at WIPP as early as May 1998. Examination and processing facilities at various DOE sites will certify that transuranic waste shipments meet the criteria for disposal at WIPP.
The Waste Isolation Pilot Plant (WIPP) in New Mexico is designed to demonstrate the safe and permanent disposal of transuranic waste in a salt formation more than 2,000 feet underground. If the demonstration is successful, WIPP will become a disposal site for transuranic waste.
DOE disposes low-level waste in engineered trenches and concrete vaults, or by shallow land burial. Waste is packaged, according to its characteristics, in drums, special boxes, or other sealed containers. A closure cap is placed on top of the contained waste, and the soil cover is sloped so that rain drains off. New technologies, stabilization techniques, and site-monitoring systems ensure protection of the environment.
Bulk low-level waste, such as rags or gloves contaminated with low levels of radioactivity, are safely disposed by shallow land burial in dry areas. When all available space in the trenches is used, earth and a protective covering for erosion control will be placed on top of the waste containers.
Hazardous waste materials are generally packaged in drums and stored on DOE sites awaiting treatment and disposal. Following treatment, hazardous waste is disposed in permitted commercial facilities and landfills. Because licensed, regulated facilities and sufficient disposal capacity are available off-site, DOE relies on hazardous waste management sites to dispose of its hazardous waste.
Mixed Waste is currently being stored pending the development and availability of additional waste treatment facilities. Disposal of mixed waste will depend on the characteristics of the residues remaining after waste treatment. These residues will be disposed accordingly in existing or new facilities. DOE published its preferred strategy for mixed waste disposal in the Waste Management PEIS. In Fiscal Year 1997, DOE will continue working with the states and others to further evaluate potential disposal sites and select a disposal configuration.
Solid low-level waste is disposed in vaults above-ground to protect the environment in humid or wet areas. This photo shows a typical vault loading operation at the Oak Ridge Site in Tennessee.
Solid and liquid non-hazardous wastes are managed and disposed at the individual DOE facilities. Standard practices used to manage these wastes, such as landfilling, are similar to practices used in municipal landfills and wastewater treatment and disposal facilities.
As the final step in the waste management process, waste disposal is the culmination of the minimization, storage, and treatment efforts that precede it. Successful long-term isolation of DOE waste will depend on scientific understanding, technology development, public acceptance, and proper management. The Department will continue to conduct extensive research to ensure that its disposal methodologies will meet the goals of safely disposing of all waste, complying with applicable laws and regulations, and preserving the quality of human health and the environment.