High-level nuclear

December. U.S. Congress approves Yucca Mountain, Nevada, as the only repositoiy site for high-level nuclear waste. 

Fig. 1. Decay of high level nuclear wastes from spent fuel as a function of storage time. Radioactivity in curies per ton of spent fuel (PWR, 3.3% enriched 2 5U, burnup 33,000 MWD/MTU at 30 MW/MTU, 5 year cooling, 99.5% U, Pu recovered)...

Along with these power plants, the U.S. could build up a fuel reprocessing capability to allow spent nuclear fuel to be reused which would lower fuel cost and eliminate the storage of high-level nuclear waste. Fuel for the reactors has been estimated to be available for 1,000 years using standard reactors with high breeding ratios and breeder reactors where more fuel is produced than consumed. 

In the meantime, nuclear power plants continue to produce an additional 2,000 short tons (1,800 metric tons) of high-level nuclear wastes every year. 

Ringwood, A. E. 1985. Disposal of high level nuclear wastes A geological perspective. Mineralogical Magazine, 49, 159-176. 

Weber, W. J., Ewing, R. C. et al. 1998. Radiation effects in crystalline ceramics for the immobilization of high-level nuclear waste and plutonium. Journal of Materials Research, 13, 1434-1484. 

Pearcy, E. C., Prokryl, J. D., Murphy, W. M. Leslie, B. W. 1994. Alteration of uraninite from the Nopal I deposit, Pena Blanca District, Chihuahua, Mexico, compared to degradation of SNF in the proposed U.S. high level nuclear waste repository at Yucca Mountain, Nevada. Applied Geochemistry, 9, 713—732. 

Mitamura, H., Matsumoto, S. et al. 1992. Aging effects on curium-doped titanate ceramic containing sodium-bearing high-level nuclear waste. Journal of the American Ceramic Society, 75, 392-400. 

Trocellier, P. 2001. Chemical durability of high level nuclear waste forms. Ann. Chim. Sci. Mat., 26, 113-130. 

This section is primarily intended to show that the relevant combination of the intrinsic physico-chemical and microscopic characteristics of HT materials, their behaviour under aggressive conditions of corrosion, and their modelled thermodynamic stability, yields a sound composite picture of these materials. On the basis of the knowledge acquired over decades on high-level nuclear waste glasses (Vernaz Dussosoy 1992 Bates et al. 1994 Thomassin 1995, 1996 Ewing 1996), these are the key parameters that may drastically influence the long-term durability of HT materials. 

Cunnane, J. C., Bates, J. K. et al. 1993. High-level nuclear-waste borosilicate glass. In Interrante, C. G. Pabalan, R. T. (eds) Scientific Basis for Nuclear Waste Management XVI. Materials Research Society Symposia Proceedings, 294, 225-232. 

The most usual route of waste classification is by radioactivity and thermal emission, mainly between high-level nuclear waste (HLNW) and low-level nuclear waste (LLNW). Depending on the countries there are other categories, such as intermediate-level nuclear waste (ILNW) and more recently another category has been introduced in order to avoid unnecessary saturation of LLNW repositories these are the so-called very low activity nuclear wastes (VLNW). 

HELP HEU HFO HFR HLW HREE HRL HT HTGR HWR Hydrological evaluation of landfill performance Highly enriched uranium Hydrous ferrous oxide or ferric hydroxide Hot fractured-rock High-level nuclear waste Heavy rare earth elements (Gd-Lu) Hard rock laboratory High temperature High-temperature gas-cooled reactor Heavy water reactor... 

Manchanda, V.K., Pathak, P.N., Rao, A.K. 2004. Di(2-ethylhexyl) pivalamide (D2EHPVA) A promising extractant for selective removal of uranium from high level nuclear waste solutions. Solvent Extr. Ion Exch. 22 (3) 353-375. 

Horwitz et al. have discussed a number of applications for Sr-Resin, including the analysis of 90Sr in high-level nuclear wastes.117"119 In conventional practice, isolation of 90Sr with Sr-Resin is a manual open-column procedure with quantification of the eluted 90Sr carried out as a separate counting step. 

Horwitz, E. P., Dietz, M. L., Chiarizia, R., Diamond, H., Maxwell, S. L., and Nelson, M. R., Separation and preconcentration of actinides by extraction chromatography using a supported liquid anion exchanger Application to the characterization of high-level nuclear waste solutions, Anal. Chim. Acta, 310, 63-78, 1995. 

The third fact is that spent nuclear fuel is not waste. Spent nuclear fuel contains 2% to 3% waste, but is about 97% recoverable uranium and plutonium. Each bundle has the potential electric energy equivalent of more than 10 million barrels of oil. High-level nuclear wastes consist of fission products and actinides that are extracted from spent fuel, but not saved for commercial use or research. Spent fuel may be temporarily stored until it is reprocessed to separate the waste from the valuable plutonium and uranium. The remaining glassified waste will then be permanently entombed. 

The act establishes a step-by-step process by which the President, the Congress, the states, affected Indian tribes, DOE, and other federal agencies can work together in the siting, construction, and operation of a high-level nuclear waste repository. One of the priorities is to strengthen consultation and... 

Chapter 4 describes how the electrical nature of corrosion reactions allows the interface to be modeled as an electrical circuit, as well as how this electrical circuit can be used to obtain information on corrosion rates. Chapter 5 focuses on how to characterize flow and how to include its effects in the test procedure. Chapter 6 describes the origins of the observed distributions in space and time of the reaction rate. Chapter 7 describes the applications of electrochemical measurements to predictive corrosion models, emphasizing their use in the long-term prediction of corrosion behavior of metallic packages for high-level nuclear waste. Chapter 8 outlines the electrochemical methods that have been applied to develop and test the effectiveness of surface treatments for metals and alloys. The final chapter gives experimental procedures that can be used to illustrate the principles described. 

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