Geological disposal

In the United States, Hquid HLW from the reprocessing of defense program fuels was concentrated, neutralized with NaOH, and stored in underground, mild steel tanks pending soHdification and geologic disposal (see Tanks AND PRESSURE VESSELS). These wastes are a complex and chemically active slurry. Suspended in the supernatant Hquid are dissolver soHds which never went into solution, insoluble reaction products which formed in the tank, and salts which have exceeded their solubiHty limit. The kinetics of many of the reactions taking place are slow (years) so that the results of characterization... 

N. A. Chapman and I. G. McKinley, The Geological Disposal of Nuclear Waste, John Wiley Sons, Ltd., Chichester, U.K., 1987. 

Geologic Disposal of Radioactive Waste" OECD Nuclear Energy Agency Paris, 1982. 

I know that there are advocates of reprocessing here today. We have concluded, however, that reprocessing is uneconomic and causes proliferation concerns. According to an Energy Resources International study, reprocessing will add about 40 percent to the price of fuel. But whether or not you share our views on reprocessing, geologic disposal of waste - for hundreds or thousands of years - is an issue that we all must face. 

The result of this effort was an ATW roadmap released by DOE just this week. It concluded that ATW would require a six-year, 281 million R D effort for open technical issues. ATW could complement geologic disposal, and any decision to pursue ATW would follow evaluation of technical, costs, and nonproliferation issues. Whether or not this effort leads to any ATW international collaboration, we are eager to expand international collaboration on nuclear waste issues in general. 

Lemire RJ, Garisto F (1989) The solubility of U, Np, Pu, Th and Tc in a geological disposal vault for used nuclear fuel AECL-10009... 

Deep geological disposal is the most favored solution for the permanent disposal of nuclear wastes with long half-lives. Although the locations of the burial places are selected with outmost care to avoid migration of the wastes in nature over a very long period of time, no barrier can be safe forever, so, numerous studies are in progress to determine the main factors that could cause leaks of radioactive nuclides. Soluble compounds in ground water are likely to play a major role in the release of actinides. 

Fleer V. N. (1982). The dissolution kinetics of anorthite (CaAl2Si20g) and synthetic strontium feldspar (SrAl2Si20g) in aqueous solutions at temperatures below 100°C With applications to the geological disposal of radioactive nuclear wastes. Ph.D. diss., Pennsylvania State University University Park. 

As in the USA, most of the HLW (SNF or immobilized HLW fluids) in Russia is destined for geological disposal. Site investigations are under way in the area of the two reprocessing facilities (Mayak and Krasnoyarsk), as well as in the regions of nuclear navy bases in the Far East and Northwest. 

Brederhoeft, J. D., England, A. W., Stewart, D. B., Trask N. J. Winograd, I. J. 1976. Geological disposal of high-level radioactive wastes -Earth-science perspectives. US. Geological Survey Circular, 779, 28 pp. 

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. 

Using the criteria listed in the introduction, we now provide a brief summary of the performance of these materials. With reference to criterion number 5, physical properties, we restrict out discussion here to the effects of radiation damage on the crystalline structure. For materials destined for geological disposal, the long-term performance in natural systems over long periods of time (e.g., 103 to 106 years) is of critical concern. Therefore, we believe that it is necessary to consider one more criterion (6) natural samples exist and allow for an assessment of the... 

Pearce, J. M., Holloway, S., Wacker, H., Nelis, M. K., Rochelle, C. Bateman, K. 1996. Natural occurrences as analogues for the geological disposal of carbon dioxide. Energy Conversion and Management, 37, 1123-1128. 

It is clear that the disposal of HLNW requires a high level of effective isolation for geological time-scales. In this context deep geological disposal has arisen as the most accepted option and there are already operational repositories of this type (waste isolation pilot plant, WIPP) in the USA, and in Finland and Sweden the plans are well advanced for the siting and construction of such facilities. 

These review papers have included the circular by the U.S. Geological Survey, Circular 779, "Geologic Disposal of High-Level Radioactive Wastes - Earth-Science Perspectives" the review by the Ad-Hoc Committee of Earth Scientists for the EPA reviews by the Office of Science and Technology Policy and finally a review prepared by an Interagency Committee chaired by the Office of Science and Technology Policy whose paper was released for public comment on July 3, 1978. 

A few of the technical issues, however, are considered by some to be very fundamental to the concept of geologic disposal in salt. Although the effects arising from these phenomena have been bounded by conservative calculations with acceptable results, it is obvious that a more quantitative understanding is desirable at the earliest possible date. Some of these issues will be discussed in the following section. 

Release rate data from actual radioactive waste forms is needed to evaluate the safety of emplacing nuclear wastes in geologic media. However, in addition to waste form development studies, such as the leach test just described, a comprehensive program was started to obtain release data from candidate waste forms for geologic disposal. 

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.)...

HIGH-HAZARD WASTE (GEOLOGIC DISPOSAL OR EQUIVALENT)... 

Reprocesing fuel to extract and glassify waste for permanent geologic disposal is the most attractive method for handling spent fuel from a safety and environmental perspective. Also recycling fuel is probably more environmentally attractive than mining more uranium, especially from lower grade ores. 

Manjanna, J., T. Kozaki, and S. Sato. 2009. Fe(III)-montmorillonite Basic properties and diffusion of tracers relevant to alteration of bentonite in deep geological disposal. Appl. Clay Sci. 43 208-217. 

Before the geological disposal concept was chosen there was a systematic analysis of potential options like sea dumping, sub-seabed disposal, in thick ice sheet, into space, transmutation etc. That analysis has shown that geological disposal is the most suitable solution for Sweden. There is also an international consensus on the acceptability in principle of deep geological repositories for disposal of SNF and high level waste. 

Based on this policy, DOE has initiated new programs that could lead to nuclear fuel cycles that significantly reduce the amount and radio toxicity of spent fuel high level waste. If implemented in practice, this would result in a hybrid spent fuel policy, using both deep geologic disposal and full recycle. This policy could possibly extend the lifespan of Yucca Moimtain by many years. This will be discussed in more detail in the next section. 

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