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Transuranic Radioactive Waste

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Sources and Volume

Transuranic (TRU) waste materials have been generated in the U.S. since the 1940's. Most of this waste originates from nuclear weapons production facilities for defense programs. "Transuranic" refers to atoms of man-made elements that are heavier (higher in atomic number) than uranium. The most prominent element in most TRU waste is plutonium. Some TRU waste consists of items such as rags, tools, and laboratory equipment contaminated with radioactive materials. Other forms of TRU waste include organic and inorganic residues or even entire enclosed contaminated cases in which radioactive materials were handled.

Some TRU waste emits high levels of penetrating radiation; this type requires protective shielding. However, most TRU waste does not emit high levels of penetrating radiation but poses a danger when small particles of it are inhaled or ingested. The radiation from the particles is damaging to lung tissue and internal organs. As long as this type of TRU waste remains enclosed and contained, it can be handled safely.

Another problem with TRU waste is that most of its radioactive elements are long-lived. That is, they stay radioactive for a long time. For example, half of the original amount of plutonium-239 in the waste will remain harmful after 24,000 years. Disposal must be carefully planned so that the waste poses no undue threat to public health or the environment for years to come.

Figure 4 Accumulated TRU Waste

Figure 4
DOE Accumulated TRU Waste
Reference: DOE/RW-0006, Rev.5

The total volume of TRU waste and TRU contaminated soil is estimated at around one million cubic meters. Figure 4 provides the historical and projected amounts of TRU wastes to the year 2015.

Site Selection for Storage and Disposal

In the past, much of the TRU waste was disposed of similarly to low-level radioactive waste, i.e., in pits and trenches covered with soil. In 1970, the Atomic Energy Commission (predecessor to the DOE) decided that TRU waste should be stored for easy retrieval to await disposal at a repository. Federal facilities in Washington, Idaho, California, Colorado, New Mexico, Nevada, Tennessee, South Carolina, Ohio, and Illinois are currently storing TRU waste.

The DOE has evaluated several alternatives for managing buried waste and contaminated soil including: (1) leaving it in place and monitoring it; (2) leaving it in place and improving the containment; and (3) removing, processing, and disposing of the waste in a repository.

As a first step in developing a permanent disposal site for TRU waste, the DOE is developing an underground, geologic repository called the Waste Isolation Pilot Plant (WIPP), near Carlsbad, NM. This site has been excavated in a salt bed about 2,100 feet underground. The WIPP will have to meet environmental standards established by the EPA before it can be used as a permanent disposal site.

If the WIPP site is eventually determined to be suitable for the disposal of TRU waste, the underground disposal area is planned to cover 100 acres. It will have a design capacity of over 2 million cubic meters, or about 850,000 barrels, of TRU waste. Figure 5 is a schematic drawing of the WIPP.

Setting Environmental Protection Standards

As stated earlier, the EPA established environmental standards applicable to spent fuel, HLW and TRU waste, but they were returned to the Agency by the courts for revision. While the Energy Policy Act specifies procedures for developing standards for a repository at Yucca Mountain, NV, the Waste Isolation Pilot Plant (WIPP) Land Withdrawal Act requires the EPA to promulgate final standards applicable to WIPP and all other spent nuclear fuel, HLW, and TRU waste disposal facilities other than those developed under the Nuclear Waste Policy Act of 1982.

The WIPP Land Withdrawal Act reinstated all of the EPA's 1985 radioactive waste disposal standards except for the sections that the court found problematic, i.e., the Individual and Ground-Water Protection Requirements of the disposal standards. The reinstated sections consist primarily of containment requirements and assurance requirements. These requirements are designed to help ensure that the wastes will be disposed of in a manner that limits the release of radioactive materials.

In 1993, EPA finalized amendments to the standards to address the court's concerns. Individual radiation protection standards will limit a person's total annual radiation exposure, considering the sum of all possible exposures. Ground-water protection standards protect present and future sources of drinking water.

New Regulatory Responsibilities for EPA

Under the WIPP Land Withdrawal Act, Congress gave EPA the responsibility for implementing its radioactive waste disposal standards at the WIPP. The Act also requires the EPA to review and approve of the DOE's plans for testing and retrieving waste at the WIPP. EPA must also ensure compliance with all federal environmental laws and regulations. In order for the WIPP to become a permanent disposal facility, the EPA must certify that the facility complies with its disposal standards. If the EPA does not certify the WIPP, the DOE must decommission the facility. Even if the EPA certifies the WIPP, the Agency will have to determine, on an ongoing basis, whether it continues to comply with the disposal standards as well as all other federal environmental laws, regulations, and permit requirements that apply. In particular, DOE must demonstrate that the WIPP complies with the Clean Air Act; the Comprehensive Environmental Response, Compensation, and Liability Act; the Solid Waste Disposal Act; the Safe Drinking Water Act; and the Resource Conservation and Recovery Act.

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