High-level waste, disposal requirements

High-level waste is waste with high concentrations of long-lived radionuclides (IAEA, 1981). High-level waste would require a disposal system considerably more confining than a near-surface facility (e.g., a geologic repository). 

Low- and high-level wastes pose very different kinds of disposal and storage problems. These problems are a result of the half-life of the isotopes present in each kind of waste. The half-life of an isotope is the time required for one-half of a given sample of the isotope to decay. The half-lives of most isotopes present in low-level wastes range from a few hours to a few years. Disposal systems need to isolate low-level wastes, therefore, for no more than a hundred years. By contrast, high-level wastes must be confined essentially forever, that is, for hundreds of thousands of years or more. 

A requirement, as stated in a recent Swedish law, for a continuation of the extensive nuclear power program in Sweden (6 operating power reactors at present and 7 more in operation in 1985) is that the engineering problems and safety aspects connected with the disposal of the high-level waste (HLW) or the unreprocessed spent uranium fuel (SUF) are thouroughly investigated. A completely safe disposal of either HLW or SUF must be guaranteed and technically proven by the nuclear power industry. 

Technical requirements on treatment and disposal of spent fuel, high-level waste, and transuranic waste established under AEA should be largely unaffected by the presence of waste classified as hazardous under RCRA Some of these wastes meet technology-based treatment standards for hazardous chemical waste established by EPA (e.gvitrified high-level waste is an acceptable waste form under RCRA). Alternatively, a finding that disposal of the radioactive component of the waste complies with applicable environmental standards established by EPA under AEA can serve to exempt the disposal facility from prohibitions on disposal of restricted hazardous chemical wastes under RCRA [e.g., disposal of mixed transuranic waste at the Waste Isolation Pilot Plant (WIPP)]. 

Spent nuclear fuel is a form of high-level waste in some definitions [e.g., NRC s 10 CFR Part 60 (NRC, 1983)] but not in others [e.g., the Nuclear Waste Policy Act (NWPA, 1982)]. This inconsistency is not important, because spent fuel and the primary waste from fuel reprocessing have similar radiological properties and require similar precautions for safe handling, storage, and disposal. Spent fuel is not a waste until it is so declared. 

Requirements for Disposal. The first requirements for disposal of commercial high-level waste were developed by AEC in 10 CFR Part 50, Appendix F (AEC, 1970). AEC specified that liquid high-level waste shall be converted to dry solids and transferred to a federal repository, to be designated later, for permanent disposal. 

Requirements for Disposal. The National Security and Military Applications of Nuclear Energy Authorization Act (NSMA, 1980) established the current DOE program for disposal of defense transuranic waste at the WIPP facility in New Mexico. The Act specifically authorized test emplacements of waste for purposes of research and development. WIPPLWA (1992) then authorized permanent disposal of defense transuranic waste at this facility. The Act specifies that the WIPP facility may not be used for disposal of high-level waste, commercial transuranic waste, or any DOE non-defense transuranic... 

Requirements for Disposal and Their Relationship to Waste Classification. Under current laws and regulations, spent fuel, high-level waste, transuranic waste, and low-level waste generally do not require particular disposal systems. However, only certain types of disposal systems are authorized for some types of waste (see Table 4.1). In particular (1) spent fuel, high-level waste, transuranic waste, and greater-than-Class-C low-level waste normally are intended for disposal in a geologic repository, such as the proposed Yucca Mountain facility and the Waste Isolation Pilot Plant and... 

Fourth, the definitions of waste classes in the United States are not related to requirements for disposal. In IAEA s waste classification system, there is some linkage between the definitions of waste classes and the types of disposal technologies that would be required, particularly for high-level waste. However, not all waste classes in IAEA s system are linked to required disposal technologies, because low-and intermediate-level waste could be acceptable for near-surface disposal or could require disposal in a geologic repository depending, for example, on the concentrations of long-lived radionuclides. 

Finally, if high-level waste is considered to be hazardous waste under RCRA, requirements on construction, operation, and closure of a disposal facility, including the provision of a liner system, leachate collection and removal system, and leak detection system (see Section 4.2.2), would need to be addressed. Such requirements are impractical at a geologic repository for disposal of high-level waste... 

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