Mixed Radioactive and Hazardous Chemical Wastes

The definition of solid waste in RCRA specifically excludes source, special nuclear, and byproduct materials as defined in AEA. Therefore, radioactive constituents of wastes that arise from operations of the nuclear fuel cycle are excluded from regulation as hazardous waste under RCRA. 

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  

dual regulation of mixed waste does not present insurmountable technical obstacles to waste disposal. The main technical impediment to successful management and disposal of mixed waste has been the difficulty in obtaining operating permits for treatment, storage, and disposal facilities under RCRA, especially facilities for mixed low-level waste at DOE sites. Similar considerations apply to waste that contains radionuclides regulated under AEA, especially low-level waste, and hazardous chemicals regulated under other environmental laws (e.g., TSCA). 

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  

NCRP s approach to addressing these difficulties is to develop a single hazardous waste classification system that is comprehensive and risk-based. 

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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. 

To classify this mixed radioactive and hazardous chemical waste based on risk, a composite risk index giving the sum of the risk indexes for chemicals that cause deterministic effects, chemicals that cause stochastic effects, and radionuclides must be evaluated. The first two elements of the composite risk index were evaluated in Sections 7.1.7.4 and 7.1.7.5, respectively. In this Section, the stochastic risk index for 137Cs in the waste is computed. 

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