Waste classification system subclassifications

The recommended risk-based waste classification system has important implications in three areas (1) the resulting classification of existing radioactive and hazardous chemical wastes, (2) subclassification of the basic waste classes, and (3) changes in existing laws and regulations that would be required to implement such a classification system. 

The further classification of low-level waste by NRC is indicated at the bottom of Figure 4.2. It is important to note that NRC s waste classification system in 10 CFR Part 61 (NRC, 1982a) does not constitute a definition of low-level waste. Rather, it is a subclassification of waste developed primarily for purposes of facilitating management and disposal of commercial low-level waste in nearsurface facilities. 

Existing hazardous waste classification systems frequently include subclassifications of basic waste classes to facilitate waste management (see Sections 2.2.4, 4.1.2 and 6.6). Examples include Class-A, -B, and -C commercial low-level waste and remotely-handled and contact-handled transuranic waste. These waste subclassifications are not expected to be significantly affected by a risk-based classification system unless particular wastes would not be generally acceptable for the disposal using the intended technology. For example, there is no inherent incompatibility with the system... 

The existing classification system for radioactive waste in the United States is depicted in Figure 1.1. This classification system is in the form of a hierarchy of basic waste classifications and waste subclassifications. 

Issues related to subclassification of basic waste classes, incorporation of conservative assumptions in applying the system, and future development needs regarding waste classification are discussed. 

The proposed framework for risk-based classification of all radioactive and hazardous chemical wastes developed in Section 6.2.2 represents waste classification in its broadest, most general terms. Thus, this classification system can be viewed as the highest level of a possible hierarchy of hazardous waste classifications (e.g., see Figure 4.2). Further subclassification of these broadly defined waste classes may be desirable for such purposes as protection of workers during waste operations, protection of public health and the environment following waste disposal, and development of efficient methods of waste management taking into account the characteristics of actual wastes. 

Subclassifications of broadly defined waste classes are commonplace in the existing classification systems for radioactive and hazardous chemical wastes in the United States (see Sections 4.1 and 4.2... 

As indicated by the current subclassifications of existing waste classes summarized above, a variety of waste properties could be used to develop meaningful subclassifications of broadly defined waste classes. These properties include, for example, waste volumes, levels of decay heat and external radiation, and the long-term persistence of the hazard posed by waste constituents. Subclassifications of waste classes also could be based on the presence of particular hazardous substances. However, if the broadly defined waste classes are based on risk, as in the classification system proposed in this Report, the intrinsic toxicity of hazardous substances normally would not provide a basis for subclassification, because this property already is accounted for in determining the basic classification of any waste. Examples of possible approaches to subclassifying the basic waste classes are discussed in the following paragraphs. 

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