Safety of nuclear waste disposal

The elucidation of actinide chemistry in solution is important for understanding actinide separation and for predicting actinide transport in the environment, particularly with respect to the safety of nuclear waste disposal.72,73 The uranyl CO + ion, for example, has received considerable interest because of its importance for environmental issues and its role as a computational benchmark system for higher actinides. Direct structural information on the coordination of uranyl in aqueous solution has been obtained mainly by extended X-ray absorption fine structure (EXAFS) measurements,74-76 whereas X-ray scattering studies of uranium and actinide solutions are more rare.77 Various ab initio studies of uranyl and related molecules, with a polarizable continuum model to mimic the solvent environment and/or a number of explicit water molecules, have been performed.78-82 We have performed a structural investigation of the carbonate system of dioxouranyl (VI) and (V), [U02(C03)3]4- and [U02(C03)3]5- in water.83 This study showed that only minor geometrical rearrangements occur upon the one-electron reduction of [U02(C03)3]4- to [U02(C03)3]5-, which supports the reversibility of this reduction. 

We can find many reports of diffusion experiments for bentonite (Gillham et al. 1983 Miyahara et al. 1991 Sato et al. 1992 Oscarson and Hume 1994 Sato and Shibutani 1994 Kozaki et al. 1999). These types of experimental data of diffusion and distribution coefficients will be used for the analysis of the long-term safety of nuclear waste disposal facilities that use bentonite clay barriers. The data, however, have not yet been estimated systematically in the sense of a theory of physical chemistry therefore it is necessary to re-assess these data not only by experiments but also from the perspective of a molecular- and multiscale-based theory. 

Bosbach D (2010) Solid-solution formation and the long-term safety of nuclear-waste disposal. 

To emphasize the difference in scale, the different classes of problems are here classified as confined problems and open-ended problems. Confined problems are those where the probability and magnitude of the risks can be quantitatively studied and are found to be limited in scope. Reactor safety and nuclear waste disposal are in this category. 

Buckau, G, C. Deguelder, and A.B. Kersting. 2(K)1. Impact of colloids on long-term safety in performance assessment of nuclear waste disposal. GEOTRAP V, Oskarshamn, Sweden, 7-7 May. 

In terms of safety, two issues are regularly debated. First, the issue of nuclear waste and, second, concerns over potential terrorist attacks on nuclear power plants. The first objection may be overcome through the introduction of new types of power plants, such as the pebble-bed modular reactor.This type of reactor uses graphite balls flecked with tiny amounts of uranium, rather than conventional fuel rods. With the fuel encased in graphite and impermeable silicon carbide, the theory is that the waste should be relatively easy to dispose of.The terrorism fears are less easily addressed and may ultimately stall the construction of new plants in countries such as the U.S., where these worries are greatest. 

Bengtsson, G. (1985) Judging the long-term acceptability of radioactive waste disposal practices from the radiation protection point of view and other perspectives. Proceedings of Seminar on Interface Questions in Nuclear Health and Safety, OECD, Paris. 

The Radioactive Waste Management Committee (RWMC) of the OECD Nuclear Energy Agency recognised the need for an internationally acknowledged, high-quality thermochemical data base for the application in the safety assessment of radioactive waste disposal, and undertook the development of the NEA Thermochemical Data... 

Applicability of the model to the experiment and feasibility of three-phase calculations in such rather complex configurations has therefore been shown, both qualitatively and quantitatively. Numerical modelling of hydro-mechanical three phase coupling can, as in the presented example, yield useful and probably critical support for the design and the safety assessment in the context of e.g. nuclear waste disposal. 

On October 1, 1976, a news item was published in the New York Times regarding the decision of the Atomic Safety and Licensing Appeals Board to stop construction indefinitely on a 6,000,000 nuclear center in Seabrook, New Hampshire, due to unsatisfactory answers to questions about the disposal of nuclear wastes. On October 9, in the same newspaper, it was reported that a fourth-year physics student at Princeton had designed an atomic bomb costing about 2,000 to build. The student pointed out that any physics major who pays attention to his teachers can design and build an atomic bomb if he can get the necessary materials. The bomb designed by this student is one-third the strength of the Hiroshima bomb exploded at the end of World War II. 

Improved understanding of the health effects of low levels of radiation, where currently standards are set by simple linear extrapolation of health effects observed at large doses, may potentially result in reassessment, either up or down, in the safety of nuclear power and the consequences of nuclear accidents. The demonstration of a threshold for radiation effects, postulated by some researchers, would result in a major decrease in the calculated consequences of severe accidents, and would also affect design requirements for radioactive waste disposal. 

Saltelli, A. and S. Tarantola (2002). On the relative importance of input factors in mathematical models Safety assessment for nuclear waste disposal. J. Am. Stat. Assoc. 97(459), 702 709. 

However, the two major problems associated with nuclecir fission power are accidents (safety) and disposal of nuclear wastes. 

NWPA provisions involved protecting public health and safety and the environment, acceptance of waste for disposal, creating a repository of permanent disposal of spent fuel and high level waste, safe transportation of waste to the repository, interim storage of spent fuel for utilities, public participation in the nuclear waste disposal solution and costs recovered from waste generators. Establishing national waste sites for HLRW is not fully resolved. 

Safety is a concern both with regard to the plant itself, and to disposal of nuclear waste. The public fear what they cannot see, smell or touch, and the risks from plant and waste effluent fall into this category. 

From a technical and economic viewpoint, COCONUT is still, in 1984, the only viable medium term strategy for most industrial nations. However, there are two other factors which have arisen to complicate the issue. One is public concern over the safety of nuclear power and the disposal of radioactive waste. The other is similar public concern over acid rain and the so-called "greenhouse effect caused by the build-up of CO2 in the stratosphere both of these undesirable effects have been ascribed to the burning of fossil fuels. These concerns are the subject of extensive public debate and professional evaluation at present and it is not profitable to speculate on the outcome[6]. Clearly, conservation alone is an inadequate strategy and the renewables will be continuously monitored and reassessed in the light of additional financial burdens which may fall on nuclear power and coal-burning to produce technical solutions which satisfy the public as regards safety and environmental issues. 

Statement of objectives to be applied to the study of radioactive waste disposal in deqp geological formations to ensure safety after the operating period of the repository. Fundamental Safety Rule - Rule No. IU.2.f. Ministry of Industry Trade, Nuclear... 

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