Radioactive waste

Radioactive wastes in the United States have many designations depending on their hazards and the circumstances and processes that created them. The NRC regulates most, but not all, sources of radioactivity, including LLW and HLW disposal, and residues from the milling of uranium and thorium. Uranium mill tailings, the final byproduct of uranium ore extrac­tion, are considered radioactive wastes. Radioactivity can range from just above background to very high levels, such as parts from inside the reactor vessel in a NPP. The everyday waste products generated in medical labora­tories and hospitals, contaminated by medical radioisotopes, is also desig­nated as RAW.

Tables 18.2 and 18.3 identify the types of commercial and DOE radioac­tive wastes. NRC regulations classify LLW in the commercial sector as Class A, Class B, and Class C. Radioactive waste owned or generated by the DOE is classified as HLW, TRU waste, or LLW. In addition, the DOE manages large quantities of uranium mill tailings and residual radioactive material. This residual radioactive material, which resulted from the Manhattan Project, is managed under the Uranium Mill Tailings and Radiation Control Act (UMTRCA) Title I. Waste may also contain hazardous waste constitu­ents. Waste with both radioactive and hazardous constituents in the United States is called ‘mixed’ waste (mixed LLW or mixed TRU waste). Generally, the source of HLW is reprocessed SNF. TRU waste consists of items such as protective clothing, tools, glassware, equipment, soils, and sludge con­taminated with man-made radioisotopes beyond or ‘heavier’ than uranium in the periodic table of the elements.

Table 18.2 US commercial RAW classification

Waste class

Description

HLW

The highly radioactive material resulting from reprocessing of spent fuel, including liquid waste produced directly in reprocessing and any solid material derived from such liquid waste containing fission products in sufficient concentrations and other highly radioactive material that the NRC, consistent with existing law, determines by rule requires permanent isolations

Class A LLW

Class A waste is determined by characteristics listed in 10 CFR 55(a)(2)(i) and physical form requirements in 10 CFR 61.56(a). (The US does not have a minimum threshold for Class A waste.)

Class B LLW

Waste that must meet more rigorous requirements on waste form than class A waste to ensure stability.

Class C LLW

Waste that not only must meet more rigorous requirements on waste form than Class B waste to ensure stability, but also requires additional measures at the disposal facility to protect against inadvertent intrusion.

GTCC LLW

LLW not generally acceptable for near-surface disposal.

AEA Section 11e. (2) byproduct material

Tailings or wastes produced by the extraction or concentration of uranium or thorium from any ore processed primarily for its source material content, including discrete surface wastes resulting from uranium solution extraction processes. Underground ore bodies depleted by such solution extraction operations do not constitute ‘byproduct material’ within this definition.15

a From the Nuclear Waste Policy Act of 1982, as amended. b Title 10 CFR Part 40, Domestic Licensing of Source Material (Section 40.4).

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