High-level waste forms

IAEA 1985. Chemical Durability and Related Properties of Solidified High Level Waste Forms. Technical Reports Series No. 257. IAEA, Vienna. 

Evans, R. 1989. Characterization of BNFL glasses containing simulated high-level waste. Proceedings Testing of High-Level Waste Forms under Repository Conditions. Cadarache, France, 1 Ob-114. 

Jercinovic, M. J., Kaser, S. Ewing, R. C. 1989. Observations of surface layers formed on basaltic and borosilicate glass 6 month and 1 year MIIT experiments. In Proceedings of the Workshop on Testing of High Level Waste Forms under Repository Conditions. EUR 12017 EN, the Commission of the European Communities, 183-191. 

Ml. McCarthy, G. J. L. Ceramics and Glass Ceramics as High-Level Waste Forms, ERDA Workshop, Germantown, Jan. 1977, p. 83. 

For any permanent high-level waste form, desirable qualities include the following ... 

Environmental Assessment - Waste Form Selection for SRP High-Level Waste. DOE/EA - 0179, Savannah River Operations Office, Aiken, SC, 1982. 

Esh, D. W., Goff, K. M., Hirsche, K. T., Battisti, T. J., Simpson, M. F., Johnson, S. G. Bateman, K. J. 1999. Development of a ceramic waste form for high level waste disposal. Materials Research Society Symposium Proceedings, 556, 107-113. 

Hench, L. L., Clark, D. E. Campbell, J. 1984. High level waste immobilization forms. Nuclear and Chemical Waste Management, 5, 149-173. 

The waste management program is therefore faced with the potential that the radioactive waste from the commercial fuel cycle could be in the form of spent fuel elements which have been declared to be waste or in the form of solidified high-level waste produced from the byproducts stream of the reprocessing plant. 

In tlie PUREX process, the spent fuel and blanket materials are dissolved in nitric acid to form nitrates of plutonium and uranium. These are separated chemically from the other fission products, including the highly radioactive actinides, and then the two nitrates are separated into tv/o streams of partially purified plutonium and uranium. Additional processing will yield whatever purity of the two elements is desired. The process yields purified plutonium, purified uranium, and high-level wastes. See also Radioactive Wastes in the entry1 on Nuclear Power Technology. Because of the yield of purified plutonium, the PUREX process is most undesirable from a nuclear weapons proliferation standpoint,... 

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)]. 

NRC thus has retained the qualitative, source-based definition of high-level waste first developed by AEC, and spent fuel is considered to be a form of high-level waste. 

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. 

Second, solidified forms of high-level waste intended for permanent disposal are subject to LDRs for hazardous waste (EPA, 1986b 1990b) discussed in the previous section (see also Section 4.2.2). LDRs specify that vitrified high-level waste is an acceptable waste form under RCRA, but there are as yet no such provisions for other forms of high-level waste that might be intended for disposal. 

Environmental Assessment. Waste Form Selection For SRP High-Level Waste, D0E/EA-0179, US Department of Energy, Washington, DC. 1982,... 

Americium and curium isotopes formed during irradiation of nuclear reactor fuels are diverted into the high-level waste (HLW) stream during fuel reprocessing. The HLW is thus the biggest... 

Fig. 21.22. Slurry-fed vitrification furnace converts aqueous high-level waste into a boro-aluminum silicate glass form. (Courtesy USDOE.)...

From power reactors with no reprocessing, the high-level waste consists of assemblies of zirconium-clad spent fuel rods to be packaged in stainless steel canisters. If the spent fuel is reprocessed, then the high-level waste will be converted to a silicate glass form similar to that from defense operations. The uranium... 

G. Dole, G. Rogers, M. Morgan, D. Stinton, J. Kessler, S. Robinson, and J. Moore, Cement-based radioactive waste hosts formed under elevated temperatures and pressures (FUETAP concrete) for Savannah River Plant high-level waste. Report No. ORNL/TM-8579 (Oak Ridge National Laboratory, 1983). 

As a radiochemist, I would like to note the great significance of chemically bonded ceramics for high level waste (HLW) treatment. It is well known that for safe storage, transportation, and disposal of radioactive waste streams, it is necessary to convert them to hardened forms. Therefore, the search for and development of a new solid matrix for immobilization of HLW forms are important, indeed. 

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