Spent nuclear fuel disposal

TABLE XVIII. ESTIMATES OF THE CONDITION OF DISPOSED SPENT NUCLEAR FUEL CONTAINERS FOR REMEDIAL ACTION CONSIDERATIONS... 

Spent nuclear fuel has fission products, uranium, and transuranic elements. Plans call for permanent disposal in underground repositories. Geological studies are in progress at the Yucca Mountain site in Nevada. Until a repository is completed, spent fuel must be stored in water pools or in dry storage casks at nuclear plant sites. 

EPA, 1985, 40 CFR Part 191, Environmental Standards for the Management and Disposal of Spent Nuclear Fuel, High-Level and Transuranic Radioactive Wastes Final Rule, Federal Register 50, no. 182 38066. 

There has been considerable interest recently in the migration of long-lived nuclides involving technetium. The behavior of technetium in groundwater, sorption and permeation under subterranean conditions needs to be studied for the purpose of assessing environmental safety in connection with the disposal of spent nuclear fuel. Chemical and physicochemical data on technetium under such conditions are necessary. 

By the year 2000, the United States will have an estimated 40,000 tons of spent nuclear fuel stored at some 70 sites and awaiting disposal. By 2035, after all existing nuclear plants have completed 40 years of operation, about 85,000 metric tons will be awaiting disposal (Slovic et al. 1991). 

Disposal of spent nuclear fuel and other radioactive wastes in the subsurface and assessment of the hazards associated with the potential release of these contaminants into the environment require knowledge of radionuclide geochemistry. Plutonium (Pu), for example, exhibits complex environmental chemistry understanding the mechanism of Pu oxidation and subsequent reduction, particularly by Mn-bearing minerals, is of major importance for predicting the fate of Pu in the subsurface. 

Fig. 1. Schematic illustration of the ideal closed nuclear fuel cycle (NRC 2003). In real practice, the reprocessing capacity does not match the generation rate of the spent nuclear fuel. Thus, the excess SNF must be placed in interim storage or disposed of in a geological repository. Under normal circumstances, the SNF will be in interim storage for just a few years. Also, note that excess material from nuclear weapons, e.g.. highly enriched 235U and 239Pu, can be blended down to lower concentrations and used as a reactor fuel.

Bunn, M., FteTTER, S., Holdren, J. P. van der ZwAAN, B. 2003. The Economics of Reprocessing vs. Direct Disposal of Spent Nuclear Fuel. Project on Managing the Atom. Final Report, December, 2003, DE-FG26-99FT4028, 127 pp. World wide web Address http //www.bcsia.ksg.harvard.edu/ BCSLA content/documents/econ reprocessing m bunn.pdf... 

Cougar, M. L. D., Siemer, D. D. Sheetz B. E. 1996. Vitrifiable concrete for disposal of spent nuclear fuel reprocessing waste at I.N.E.L. Materials Research Society Symposium Proceedings, 412, 395-402. 

Poinssot, C., Lovera, P. Faure, M.-H. 2002. Assessment of the evolution with time of the instant release fraction of spent nuclear fuel in geological disposal conditions. Materials Research Society Symposium Proceedings, 713, 615-623. 

Wronkiewicz, D. J. Buck, E. C. 1999. Uranium mineralogy and the disposal of spent nuclear fuel. In Burns, P. C. Finch, R. (eds) Uranium Mineralogy, Geochemistry and the Environment. Mineralogical Society of America, Reviews in Mineralogy, 38, 475-497. 

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. 

The extent to which differences in waste classification and approaches to waste management may impede the disposal of high-level radioactive waste and spent nuclear fuel is not yet clear because of uncertainties in the final waste forms intended for disposal and the fact that siting and licensing of a repository is still in the investigative phase. 

EPA (1985). U.S. Environmental Protection Agency. 40 CFR Part 191—Environmental radiation protection standards for management and disposal of spent nuclear fuel, high-level and transuranic radioactive wastes, 50 FR 38066 (U.S. Government Printing Office, Washington). 

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