Radioactive geologic isolation

All the countries that produce nuclear waste have chosen the same alternative for the ultimate disposition of HLW, deep geological isolation, and they did so indepeiideiitly of one another. The United States has the most radioactive nuclear waste and the most complicated array of waste types of any nuclear country. Only in the United States can one find the same economy of scale for waste handling. Thus, it leads the world in most activities aimed at safe isolation. Ill France, Japan, and Great Britain, however, reprocessing is routinely practiced. Those countries reprocess HLW for many other countries. As mentioned above, reprocessing is not currently allowed in the United States. 

The objective of geologic isolation of radioactive wastes is to preclude their reaching the biosphere until after they have decayed to the extent that they no longer constitute a health hazard. Concern over radioactive wastes from military, industrial and research uses has elicited many lines of commentary and deep concern from many individuals. In California, the concern about waste disposal was the focal point in establishing a moratorium on the construction of new reactors until a satisfactory waste disposal technology could be demonstrated. 

For purposes of assessing the safety of repositories of radioactive wastes placed in geologic isolation, actinide behavior in the environment has been interpreted in terms of five steps of prediction ... 

The hydrolytic chemistry of Pu is important in that it affects the behavior and mobility of plutonium in the environment [A2] and in geologically isolated radioactive wastes that may be subjected to slow leaching by ground water. The absorption spectra of the Pu(TV) polymer is similar to that of the plutonium hydroxide precipitate Pu(0H)4 [L4]. Experimental data in Fig. 

Kiihn, K., and J. Hamstra Geologic Isolation of Radioactive Wastes in the Federal Republic of Germany and the Respective Program of the Netherlands, Proceedings of the International Symposium on the Management of Wastes from the LWR Fuel Cycle, Denver, 1976, Report CONF-76-0701, p. 580. 

Board on Radioactive Waste Management, National Research Council (1999). Discussion Papers prepared for the Workshop on Disposition of High-Level Radioactive Waste Through Geological Isolation, National Academy Press, Washington, DC. 

Witherspoon, P. A. (ed.) (1996). Geologic Problems in Radioactive Waste Isolation, Second Worldwide Review, Lawrence Berkeley National Laboratory, University of California, Berkeley, CA. 

HLW generally refers to materials requiring permanent isolation from the environment. It frequently arises as a by-product of nuclear power generation (reprocessing streams or spent fuel) or from the isolation of fissile radionuclides from irradiated materials to be used in nuclear weapons production. When nuclear fuel from reactor operations (civilian or defense) is chemically processed, the radioactive wastes include highly concentrated liquid solutions of nuclear fission products. Typically, these waste streams are solidified either in a glass (vitrification) or in another matrix. Both the liquid solutions and the vitrified solids are considered HLW. If the nuclear fuel is not processed, it too, is considered as HLW and must be dispositioned. The path most often proposed is direct, deep geologic isolation. 

Commission of European Community, Performance Assessment of Geological Isolation Systems for Radioactive Wastes, (EWU 11777) (1988). 

The change in the concentration of radioactive elements over time in far-field environments can be expressed as follows (Performance Assessment of Geological Isolation Systems (PAGIS) 1984) ... 

National Research Council. 1999. Disposition of high-level radioactive waste through geological isolation Development, current status, and technical and policy challenges. Natl. Academy Press, Washington, DC. ... 

D Alessandro, M. Gera, F. 1986. Geological isolation of radioactive waste in clay formations fractures and faults as possible pathways for radionuclide migration. Radioactive Waste Management and the Nuclear Fuel Cycle, 7(4), 381-406. 

Shurr, G.W. "The Pierre Shale, Northern Great Plains a Potential Isolation Medium for Radioactive Waste", U.S. Geological Survey Open-File Report 77-776, 1977. 

Radioactive wastes are usually stored in underground tanks or in temporary storage at reactor sites for recycling or disposal (Whicker and Schultz 1982a). For low-level wastes, containment and isolation are the preferred disposal options, including burial, hydraulic injection into deep geological strata, and ocean disposal (Table 32.10). Options for the disposal of high-level wastes include... 

Natural systems have been studied to provide data to support the ability of geological repositories to isolate radioactive wastes (e.g.,... 

Figure 16.11 Water dilution volume for radionuclides in PWR spent fuel. (From National Research Council, A Study of the Isolation System for Geologic Disposal of Radioactive Waste, NAS, Washington, 1983.)...

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