Classification and Disposal of Radioactive Waste

This Section discusses the historical development and current approaches to classification and disposal of radioactive waste. Classification and requirements for disposal of different radioactive wastes in the United States are emphasized, particularly the relationship between waste classification and requirements for disposal much of this discussion is adapted from a previous paper (Kocher, 1990). Proposals for alternative radioactive waste classification systems are reviewed. Classification systems developed by the International Atomic Energy Agency (IAEA) and the relationship between waste classification and disposal requirements in IAEA recommendations are discussed in some detail. Waste classification systems developed in other countries are briefly mentioned. 

Classification of radioactive waste has been facilitated by two considerations. The first is that radiation dose provides a common measure of potential health impacts from exposure to any radionuclide and for any exposure situation (see Section 3.2.2). All classification systems for radioactive waste take into account, at least to some 

A second consideration that has been important, at least implicitly, in developing classification systems for radioactive waste is natural background radiation. The presence of a ubiquitous and unavoidable background of radiation and its description in terms of radiation dose provide a measure of the significance of potential exposures of radiation workers and members of the public to any radioactive waste. Levels of radiation in waste materials compared with levels of natural background radiation have played an important role in radioactive waste classification. 

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Wastes have been classified for decades for a variety of purposes. This Section discusses the historical development of classification systems for radioactive and hazardous chemical wastes and the resulting classification systems in use at the present time. The relationship between waste classification and requirements for disposal of different classes of hazardous waste is emphasized. The framework for this discussion is the top-level system for waste classification in the United States shown in Figure 4.1. Within this framework, it is first determined whether a waste is nonhazardous (e.g., municipal waste) these wastes are not addressed in this Report. If a waste is deemed hazardous, it is so classified due to the presence of radionuclides or hazardous chemicals. Mixed radioactive and hazardous chemical waste is not a separate class of waste. However, mixed waste has been an important concern as a result of differences in requirements for management and disposal of radioactive and hazardous chemical wastes. Section 4.1 addresses classification and disposal of radioactive waste, and is followed by discussions of classification and disposal of hazardous chemical waste in Section 4.2 and approaches to management of mixed radioactive and hazardous chemical waste in Section 4.3. Finally, Section 4.4 summarizes previous NCRP recommendations relevant to waste classification. 

KOCHER, D.C. (1990). Classification and disposal of radioactive wastes— History and legal and regulatory requirements, Radiat. Prot. Manage. 7, 58-78. 

The classification system lacks a set of principles for determining when a waste contains sufficiently small amounts of radionuclides that it can be exempted from regulatory control as radioactive material. The lack of a general class of exempt waste increases in importance as the resources required for management and disposal of radioactive waste increase compared with the resources required for management and disposal of these materials as nonradioactive waste, and it may foreclose possible beneficial uses of slightly contaminated materials. 

NCRP s recommendations on classification of hazardous wastes are intended to address deficiencies and inconsistencies in the separate systems for classification and disposal of radioactive and hazardous chemical wastes in the United States summarized previously. The most important of these include ... 

Unfortunately, however, it is difficult for anyone to fully comprehend the existing classification systems for radioactive and hazardous chemical wastes. These systems are not based on clearly stated principles from which a logical and transparent classification system might follow, and the two systems approach classification and disposal of hazardous waste in different ways. The systems intermix legal and technical considerations in ways that sometimes defy logic. A few examples of the incongruities in the waste classification systems that result in a lack of transparency and difficulties in comprehension are described below. 

This Section summarizes the separate classification systems that have been developed for radioactive and hazardous chemical wastes. Impacts of the two classification systems on management and disposal of mixed wastes are also described. 

Classification and Disposal of Wastes from the Nuclear Fuel Cycle. This Section discusses the different classes of radioactive waste that arise from operations of the nuclear fuel cycle that have been defined in laws and regulations over the last three decades and... 

Characteristics of the system for classification and disposal of fuel-cycle waste. The current classification system for radioactive waste that arises from operations of the nuclear fuel cycle in the United States and the current requirements for disposal of waste in the different classes have the important characteristics discussed below. 

CFR 61, Licensing Requirements for Land Disposal of Radioactive Waste. 1 These regulations supply guidance for land disposal of radioactive waste. 10 CFR is applicable when DOE would wish to dispose of DSO material from N Reactor and may be applicable if it is desired to leave some level of radioactivity in situ. Determine if the classification of waste is low-level (i.e., not high-level). 1 2 3 4... 

A general class of exempt radioactive waste would include any waste containing sufficiently small amounts of radionuclides that the materials could be managed and disposed of as if they were nonradioactive and still provide adequate protection of human health. An important benefit of establishing a general class of exempt radioactive waste would be a reduction in the resources required for waste treatment and disposal. Classification of waste as exempt also would allow consideration of beneficial uses of the materials. 

The radioactive waste classification system is complex, it is not transparent to the public, who are increasingly involved in decisions about management and disposal of waste, and it is not understandable by anyone but a studied expert. 

As part of this study, proposed radioactive waste classification systems that differ from the existing classification system in the United States were reviewed and evaluated. Of particular interest is the classification system currently recommended by the International Atomic Energy Agency (IAEA). This classification system and the disposal options for each waste class are summarized in Table 1.2. The basic waste classification system consists of exempt waste, low-and intermediate-level waste, and high-level waste. 

Table 1.2—Summary of characteristics of radioactive wastes and disposal options in waste classification system... 

The similarities are of the following kinds. First, neither classification system includes a general class of exempt waste. Second, neither classification system is comprehensive, because the classification system for radioactive waste distinguishes between fuel-cycle and NARM waste and the classification system for hazardous chemical waste excludes many potentially important wastes that contain hazardous chemicals. Third, any waste must be managed and disposed of in a manner that is expected to protect public health and the environment. In addition, the approach to disposal of hazardous chemical waste under RCRA, which emphasizes monitoring of releases from disposal facilities and an intention to maintain institutional control over disposal sites for as long as the waste remains hazardous, is applied to disposal of uranium or thorium mill tailings under AEA. 

The term mixed waste refers mainly to waste that contains radionuclides regulated under AEA and hazardous chemical waste regulated under RCRA. Dual regulation of mixed waste has no effect on classification, management, and disposal of the hazardous chemical component or on classification of the radioactive component. The effects of dual regulation of mixed waste on management and disposal of the radioactive component are summarized as follows ... 

Inclusion of NARM waste in the same classification system with radioactive waste that arises from operations of the nuclear fuel cycle would require a change in the scope of AEA, because management and disposal of commercial NARM waste cannot be regulated under AEA. 

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