Waste classification system exemption

Based on these principles, the hazardous waste classification system recommended by NCRP includes three classes of waste exempt, low-hazard, and high-hazard waste. Each waste class is defined in relation to the type of disposal system (technology) that is expected to be generally acceptable in protecting public health as follows ... 

Exempt Radioactive Wastes. The radioactive waste classification system in the United States does not include a general class of exempt waste (see Table 1.1). Rather, many products and materials that contain small amounts of radionuclides (e.g., specified consumer products, liquid scintillation counters containing 3H and 14C) have been exempted from requirements for use or disposal as radioactive material on a case-by-case basis. The various exemption levels are intended to correspond to low doses to the public, especially compared with dose limits in radiation protection standards for the public or doses due to natural background radiation. However, the exemption levels are not based on a particular dose, and potential doses to the public resulting from use or disposal of the exempt products and materials vary widely. 

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. 

The basic waste classification system includes a general class of exempt waste, which is defined in terms of a dose to an individual member of the public, resulting from waste disposal, that is regarded as negligible. 

Legal impediments to development of a new waste classification system would be ignored. These include, for example, the distinction between radioactive waste that arises from operations of the nuclear fuel-cycle and NARM waste, which is based on provisions of AEA, the distinction between radioactive and hazardous chemical wastes, which is based on provisions of AEA and RCRA, and the provision in the National Energy Policy Act that prohibits NRC from establishing a general class of exempt radioactive waste. 

A general class of exempt waste, which could be regulated as nonhazardous material, would be established. Development of an exempt class of waste that contains low levels of hazardous substances has been controversial and currently is banned by law in the case of radioactive waste. Some radioactive and hazardous chemical wastes have been exempted on a case-by-case basis, but general principles for exempting radioactive or hazardous chemical wastes have not been established. In spite of these difficulties, however, a meaningful risk-based waste classification system must include a general class of exempt waste. 

The waste classification system presented in this Report would apply to all radioactive and hazardous chemical wastes from any source, and it would be based on considerations of health risks to the public that arise from waste disposal. The recommended classification system differs from the existing waste classification systems in three respects radioactive and hazardous chemical wastes would be included in the same classification system all waste would be classified based on its properties, rather than its source and the classification system would include a general class of exempt waste. 

Many details would need to be considered in developing a new waste classification system based on the framework presented in this Report. Assumptions about generic scenarios for exposure of hypothetical inadvertent intruders at waste disposal sites to be used in classifying waste and the time frames for applying the scenarios would be required. Decisions would need to be made about negligible and acceptable (barely tolerable) doses or risks that would be used in classifying waste as exempt or low-hazard, respectively. 

The waste classification system developed in this Report includes a general class of exempt waste. Waste in this class would contain sufficiently small amounts of hazardous substances that it could be managed in all respects as if it were nonhazardous (e.g., as household trash). NCRP intends that exempt materials could be used or disposed of in any manner allowed by laws and regulations addressing disposition of nonhazardous materials. However, exempt waste would not necessarily be exempt for purposes of beneficial use without further analysis of the risks associated with anticipated uses. Materials could be exempted for purposes of disposal or beneficial use based on similar considerations of acceptable risk. However, based on differences in exposure scenarios for the two dispositions, limits on the amounts of hazardous substances that could be present in exempt materials intended for beneficial use could be substantially lower than the limits for disposal as exempt waste. Thus, disposal may be the only allowable disposition for some exempt materials based on considerations of risk. In addition, some exempt materials may consist of trash, rubble, and residues from industrial processes that would have no beneficial uses and must be managed as waste. 

To address the limitations of the waste classification system described above, new recommendations on waste classification were developed (IAEA, 1994). A particular aim of the new system was to associate waste classes with intended disposal technologies (options), at least to some degree. The recommended classification system includes the following three major classes of waste exempt waste, low- and intermediate-level waste, and high-level waste. These waste classes and the associated disposal options are summarized in Table 4.2 and described as follows. 

In its recommendations, IAEA emphasizes that waste classification, even if it focuses on waste disposal, does not provide an adequate substitute for site-specific safety assessments of particular disposal systems to ensure the acceptability of waste disposal. IAEA also recognizes the role of national authorities in implementing waste classification systems and ensuring the safety of waste disposal, and that different countries may choose to classify waste in different ways depending on their particular situations. However, IAEA believes that, if for no other reason than to facilitate communication, it would be desirable to achieve some level of uniformity of waste classification systems in different countries. IAEA recommends that it is particularly important to obtain an international consensus on the boundary for determining unconditionally exempt material that may be transferred from one country to another, especially for purposes of recycle/reuse. 

A number of alternatives to the qualitative and source-based classification system for radioactive waste in the United States have been proposed. The alternative waste classification systems have three important features in common. First, they are comprehensive, in that NARM waste and nuclear fuel-cycle waste are included in the same classification system. Second, they are based on the concept that waste classes should be defined primarily on the basis of risk, particularly the risk resulting from waste disposal. Finally, to some degree, they associate waste classes with particular disposal systems that are expected to be generally acceptable. None of these features is embodied in the radioactive waste classification system in the United States. In addition, some proposed classification systems include an exempt class of radioactive waste that contains negligibly small amounts of radionuclides. Waste in this class would be regulated in all respects as if it were nonhazardous. A general class of exempt waste is not included in the radioactive waste classification system in the United States. 

Previous sections have presented technical and historical information on radiation and chemical risk assessment and on classification of radioactive and hazardous chemical wastes. This information provides important perspectives for establishing the foundations of a new hazardous waste classification system. Before establishing these foundations, it is useful to specify the attributes that an ideal waste classification system should possess. The following sections identify the desirable attributes of a waste classification system including that the system should be risk-based, it should allow for exemption of waste, and it should be comprehensive, consistent, intrinsic, comprehensible, quantitative, compatible with existing systems, and flexible. These attributes should be recognized as goals that are not all likely to be fully realized in a practical waste classification system. 

The basic element of the recommended framework for a comprehensive and risk-based waste classification system is the assumption that any waste that contains sufficiently small amounts of radionuclides or hazardous chemicals should be classified as exempt, or essentially nonhazardous. Waste that contains greater amounts of hazardous substances then would be classified as nonexempt, and further classification of nonexempt wastes, based also on the amounts of hazardous substances present, would be appropriate. 

The provision of the National Energy Policy Act (NEPA, 1992) that prohibits NRC from establishing dose criteria that could be used to exempt radioactive wastes from licensing requirements for disposal clearly is an impediment to development of generally applicable exemption levels for radioactive waste. An exempt class of radioactive and hazardous chemical waste is the cornerstone of the risk-based waste classification system developed in this Report, and any legal and regulatory impediments to establishment of generally applicable exemption levels would need to be removed. 

An additional constraint under RCRA that would need to be addressed in implementing the waste classification system presented in this Report involves solid waste that is identified as hazardous by listing (see Section 4.2.1). At the present time, any solid waste that is hazardous by listing cannot be rendered nonhazardous by treatment. Rather, in accordance with the mixture and derived-from rules in 40 CFR Part 261 (EPA, 1980b 1992c 2001b), any listed waste is considered to be hazardous regardless of the concentrations of listed hazardous substances, unless the waste is specifically delisted. The waste classification system developed in this Report, which includes an exempt class of waste as an essential element, could be implemented only if these rules were revised to allow establishment of exemption levels for listed hazardous chemical wastes. 

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. 

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. 

Thus, the basic elements of the proposed classification system are, first, that there should be a general class of waste that contains sufficiently small concentrations of radionuclides or hazardous chemicals that it can be exempted from regulatory control as hazardous material and, second, that there should be two classes of nonexempt waste that contain increasing concentrations of hazardous substances and require dedicated disposal systems that provide increased waste isolation. 

The most profound change in waste classification that would result from implementation of the system proposed in this Report would be the establishment of an exempt class of waste. This class would be defined based on the principle that waste could be regulated as if it were nonhazardous if the hazardous constituents were present in amounts sufficiently low that the risk from disposal would be negligible (de minimis). At present, EPA has not established general provisions for exemption of listed hazardous chemical wastes regulated under RCRA, and efforts by NRC to establish general conditions for exemption of radioactive wastes were halted at the direction of Congress. 

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