Nuclear waste applications

While each of the above technologies offers certain unique advantages, those common to ceramic immobilization include a relative ease in fabrication, a high capacity for actinides or heavy metals compared to other technologies, the capacity for flexibility of feedstock, the ability to add neutron absorber materials for nuclear waste applications, and the ability to control the properties of the final waste form. 

Scientists develop a nickel-gadolinium alloy that absorbs radioactive neutrons emitted by nuclear waste. Applications include transport and storage of highly radioactive fuel. 

The advent of a portable source of very high energy x-rays has opened up x-ray inspection possibilities in a wide range of environments. Applications include such fields as nuclear waste containers, bridges, nuclear and fossil power plants, surface and airborne transportation systems, space launch systems and other thick section NDT and other inspection problems that cannot be solved imaged using other NDT methods. 

Spouted beds Wiirster coaters Moderate (layered) 50 ton/hr continuous cohesive powders, good for coating applications detergents Batch pharmaceuticals, agricultural chemicals, nuclear wastes... 

A question of practical interest is the amount of electrolyte adsorbed into nanostructures and how this depends on various surface and solution parameters. The equilibrium concentration of ions inside porous structures will affect the applications, such as ion exchange resins and membranes, containment of nuclear wastes [67], and battery materials [68]. Experimental studies of electrosorption studies on a single planar electrode were reported [69]. Studies on porous structures are difficult, since most structures are ill defined with a wide distribution of pore sizes and surface charges. Only rough estimates of the average number of fixed charges and pore sizes were reported [70-73]. Molecular simulations of nonelectrolyte adsorption into nanopores were widely reported [58]. The confinement effect can lead to abnormalities of lowered critical points and compressed two-phase envelope [74]. 

Before leaving ionic liquids it is worth mentioning their potential value in separation processes. Organic solvents are frequently used in multiphase extraction processes and pose the same problems in terms of VOC containment and recovery as they do in syntheses, hence ionic liquids could offer a more benign alternative. Interesting applications along this line which have been studied include separation of spent nuclear fuel from other nuclear waste and extraction of the antibiotic erythromycin-A. 

Similar demands for reference materials also arise in connection with the monitoring of radioactivity in and around nuclear installations (nuclear power plants, nuclear fuel and reprocessing plants, and nuclear waste facilities). These, in fact, are now the main applications of radionuclide reference materials. 

Worldwide, there are numerous plasma system designs for treatment of all types of wastes. Economical considerations limit their commercial applications to the most profitable actions. Presently they commercially operate in Switzerland and Germany for low level nuclear waste vitrification, in France and the USA for asbestos waste vitrification, in the USA and Australia for hazardous waste treatment, in Japan and France for municipal fly ash vitrification. The most of installations is working in Japan because there 70% of municipal waste is incinerated and the ash can not be used as landfill. EU Regulations banning the disposal to landfill of toxic and hazardous wastes after year 2002 may cause wider use of plasma waste destruction technology in Europe. 

Future improvements in the application of laboratory dissolution data to natural systems will come not (only) from additional work on laboratory kinetics, but will also depend heavily on much more comprehensive studies of surface area distribution, evolution, and accessibility to attack by fluids in natural systems, and by improved understanding of thermodynamic properties of natural fluids. Only in this way will laboratory kinetic data contribute to solving environmental problems such as nuclear waste disposal and evaluating the impact of acid deposition. 

After the separation of the actinides from the high-level waste, it is desirable to remove certain other fission products from the nuclear wastes. Some Cs and Sr are low-charged cations that react well with macro-cyclic ligands (e.g., crown ethers, calixarenes). Research to synthesize and investigate the properties of macrocyclic ligands for application in nuclear waste treatment has been an active effort internationally. Some of the results obtained are discussed in section 12.7. 

In the past, the extraction of Sr and Cs was investigated for some practical applications (heat and gamma ray sources) but the main interest today is for decreasing the thermal power and the potential hazard of nuclear waste in underground repositories. Results of extractions with some... 

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. 

The Met-Tech separation process is a liquid ion exchange process for the ex situ recovery, separation, and concentration of a wide range of heavy metals. The technology is commercially available and, according to the vendor, has been tested at the pilot scale. According to the vendor, future applications will be in soil remediation, acid mine drainage, and the recycling of spent nuclear waste. 

Ewing, R. C. Jercinovic, M. J. 1987. Natural analogues Their application to the prediction of the long-term behavior of nuclear waste forms. In Bates, J. K. Seefeldt, W. B. (eds) Scientific Basis for Nuclear Waste Management X. Material Research Society Symposium Proceedings, 84, 67-86. 

Plodinec, M. J. Wicks, G. G. 1994. Application of hydration thermodynamics to in-situ test results. In Barkatt, A. Van Konynenbourg, R. A. (eds) Scientific Basis for Nuclear Waste Management XVII. Materials Research Society Symposia Proceedings, 333, 145-157. 

There are inherent scale limitations in the time and space dimensions covered by laboratory studies. The applicability of the near field geochemical models derived from laboratory observations have to be applied to long-term, large-scale situations like the ones involved in the safety assessment of nuclear waste repositories. Hence, there is a need to test the models developed from laboratory investigations in field situations that are related to the ones to be encountered in repository systems. 

Linard, Y., Advocat, T., Jegou, C. Richet, P. 2001. Thermochemistry of nuclear waste glasses Application to weathering studies. Journal of Non-Crystalline Solids, 289, 135-143. 

Solid State Reaction - Hexaaluminates have been long known as interesting materials for many applications (electrical ceramics, matrices for permanent immobilization of radioactive elements from nuclear wastes and refractory cement and concrete). For many years ceramists prepared hexaaluminates via solid state reaction for both crystallographic and application purposes.6... 

Cowan, G. A., "Migration Paths for Oklo Reactor Products and Application to the Problem of Geological Storage of Nuclear Wastes", IAEA Symp., Paris, Dec. 19-21, 1977... 

The discussion in Section 7.6 is not intended to imply that the three methods of depressurization, thermal stimulation, and inhibitor injection are the only means of hydrate dissociation. Because the hydrate science is available as indicated in the earlier chapters of this book, the application of that science to recovery from hydrates is an exercise for the innovative engineer. Novel ideas such as fire flooding (Halleck et al., 1982), burial of nuclear wastes (Malone, 1985, p. 27), and the use of electromagnetic heating (Islam, 1994) are only three innovative ways of dissociating hydrates, but none have been tried. However, in this portion of the chapter, it is intended to describe trends for dissociating hydrates in several kinds of reservoirs, as an indication of the future. 

Choppin, G.R. 1999. Overview of chemical separation methods and technologies. In Chemical Separation Technologies and Related Methods of Nuclear Waste Management Application, Problems and Research Needs. Choppin, G.R., Khankhasayev, M.Kh. Eds. Kluwer Academic, Netherlands, pp. 1-15. 

Erlinger, C.V. 1998. Towards a physical interpretation of third phase formation in liquid-liquid extraction. Application to the DIAMEX process for the treatment of high radioactive nuclear wastes. Thesis. University Paris XI, Paris. 

Moyer, B.A., Birdwell, J.F. Jr., Bonnesen, P.V., Delmau, L.H. 2005. Use of macrocycles in nuclear-waste cleanup A real-world application of a calixcrown in technology for the separation of cesium. In Macrocyclic Chemistry - Current Trends and Future Prospectives. Gloe K. Ed., Springer, Dordrecht, pp. 383-405. 

Horwitz, E.P., Schulz, W.W. 1990. The TRUEX process A vital tool for disposal of US defense nuclear wastes. Conference on New Separation Chemistry for Radioactive Waste and Other Specific Applications, May, Rome, Italy. 

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. 

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