Treatment of Radioactive Waste

The solid, liquid and gaseous radioactive waste (see marginal notes) produced during the reprocessing of spent fuel elements has to be safely stored, to prevent entry into the biosphere. 

Typical quantities of waste per t of irradiated uranium fuels with a burn up of  

Glasses are stable to irradiation, resistant to leaching and dissipate the decay-heat efficiently to the environment. 

A new scrubbing process for the extraction agent makes it possible to reduce strongly the quantity of MAW 

Treatment of medium activity solid waste (cladding, structural component)  

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The properties of hydrated titanium dioxide as an ion-exchange (qv) medium have been widely studied (51—55). Separations include those of alkaH and alkaline-earth metals, zinc, copper, cobalt, cesium, strontium, and barium. The use of hydrated titanium dioxide to separate uranium from seawater and also for the treatment of radioactive wastes from nuclear-reactor installations has been proposed (56). 

Process economics of the GMODS are dependent on the scale of operation (D14276H, p. 5). Based on theoretical considerations (the limited number of process steps), GMODS has the potential to be a relatively low-cost process for treatment of radioactive wastes (D14276H, p. 37). In some cases, specialized equipment may be used to minimize waste volume prior to treatment, in an effort to minimize costs (D14276H, p. A-3). 

Pretreatment is required for HTV processing. Drying and size reduction of wastes are required. Additives such as glass formers may be required. Processing of nonhazardous wastes may not be economically feasible. Treatment of radioactive wastes will produce a radioactive glass that requires special handing or treatment. 

IAEA, Application of Ion Exchange Processes for the Treatment of Radioactive Waste and Management of Spent Ion Exchangers, Technical Reports Series No. 408, International Atomic Energy Agency (IAEA), Vienna (2002)... 

The economic break between fixed bed and continuous operation has been estimated as ion concentrations of 0.57V, or flow rates above 300 gpm, or when three or more parallel beds are required to maintain continuous operation. The original application of continuous ion exchange was to treatment of radioactive wastes, but some installations of ordinary water treating have been made. 

The UNEX Process A Universal Solvent Intensive collaboration between the INL and the Khlopin Radium Institute of Saint Petersburg (KRI, Russia) since 1994 has resulted in the development of the UNEX process for the treatment of radioactive waste stored at the INL (116-125). The UNEX process is based on the following tertiary solvent ... 

Todd, T. A., Law, J. D., Herbst, R. S., Lumetta, G. J., and Moyer, B. A. Treatment of Radioactive Wastes Using Liquid-Liquid Extraction Technologies—Fears, Facts, and Issues, Proc. Waste Management 00, Tucson, AZ, March 2000. 

Adsorption at the solution-carbon interface is already widely used on a large scale for water treatment, decolorizing, gold recovery, etc. (Derbyshire et al., 1995). In addition to these well-established applications, considerable interest is now being shown in the potential use of activated carbons for the removal of a wide range of pollutants such as aromatic hydrocarbons, humic acids and heavy metal ions (Costa et al., 1988 Youssef et al., 1996) and for the treatment of radioactive waste (Qadeer and Saleem, 1997). The aims of the applied research are generally to optimize the performance of the available commercial grades of activated carbon, to develop new products and to elucidate the mechanisms of adsorption (Blasinski et al., 1990). 

Ruzankin A.D., Makeenko S.G. (2000) Organizational and economic problems of treatment of radioactive waste in the European north of Russia, Kola Science Centre RAS Apatity (in Russian). 

The waste streams may be disposed safely if they do not contain contaminants that are harmful to living beings. Several waste streams, however, contain harmful chemicals that enter the human body through the food chain via soil or water or the air that we breathe. These contaminants may be toxic chemicals or radioactive. The former is referred to as hazardous , and the latter as radioactive . Both need treatment to isolate the contaminants from the groundwater, air, and soil prior to disposal. Treatment of hazardous waste streams is the subject of this chapter, while treatment of radioactive wastes, or those containing both hazardous and radioactive contaminants ( mixed wastes), is discussed in Chapter 17. 

Because of the above advantages, it is not surprising that the hterature on phosphate stabilization has undergone a sudden explosion. This interest is not hmited to the stabilization of hazardous contaminants alone, but radioactive elements as well. The role of the phosphate treatment of radioactive wastes will be discussed in the next chapter. 

Gumming, I.W., and A.D. Turner, 1989, Optimization of an UF pilot plant for the treatment of radioactive waste, in Future Industrial Prospects of Membrane Processes (L. Cecille and J.C. Toussaint, Eds.), Elsevier Applied Sci., London, U.K., p. 163. 

Francis A. J. (1994) Microbiological treatment of radioactive wastes. In Chemical Pretreatment of Nuclear Waste for Disposal (eds. W. W. Schulz and E. P. Horwitz). Plenum, New York, pp. 115-131. 

Reverse osmosis preceded by microfiltration or ultrafiltration is considered as an option for the treatment of radioactive wastes from Romanian nuclear centers. Effective studies are carried on at Research Center for Macromolecular Materials and Membranes, Bucharest and at Institute of Nuclear Research, Pitesti aiming in employing these pressure-driven techniques for cleaning the wastes from decontamination of nuclear installations and reactor primary circuit [34,35]. 

One of the current researches devoted to membrane treatment of radioactive waste is directed toward seeded ultrafiltration and all methods, which combined with ultrafiltration, give considerable enhancement of separation (Table 30.6). 

FIGURE 30.14 Pilot plant for treatment of radioactive wastes by UF/complexation. (Reprinted from Zakrzewska-Trznadel, G. and Harasimowicz, M., Desalination, 162, 191, 2004. Copyright (2004) with permission from Elsevier.)... 

Some areas of application are the nuclear industry and the treatment of radioactive liquid wastes, with two main purposes reduction in the waste volume for further disposal, and reuse of decontaminated water. Pressure-driven membrane processes (microfiltration, ultrafiltration, nanofiltration, and reverse osmosis [RO]) are widely used for the treatment of radioactive waste. 

Membrane technologies have a great potential in the treatment of radioactive liquid wastes, as it has been proved throughout this chapter. In this sense, it is expected a growing use of the membrane processes in the radioactive field, with different possibilities alone, combined between them (microfiltration or ultrafiltration and reverse osmosis) or combined with other conventional processes like evaporation or ion exchange. Furthermore, some special membrane processes, like membrane distillation or liquid membranes, could be applied for the specific treatment of radioactive wastes. 

Hydrothermocompression reactions. Formation and solidification of materials or composites such as in the treatment of radioactive waste, solidification of special... 

Early applications were related to industrial processes and focussed on the sampling of metal ions in natural waters [96], the determination of phenylalanine using in-line ion-exchange [97], modelling of heavy metal adsorption [98], use of pulsed flows for nickel removal from acidic solutions [99], investigation of properties inherent to fluidised beds and transport reactors [100], and treatment of radioactive wastes [101]. The characteristics, limitations and applications of fluidised beads are provided elsewhere [102—104],... 

These distillation units, with capacities of typically up to 50 m /d, have played a major role in the treatment of radioactive waste since their steady and reliable operation over many years has ensured that the high-level hquid waste from the nuclear fuel cycle routinely has been reduced in volume for safe storage prior to further treatment to condition it for disposal and long-term isolation from the biosphere. 

Thermal plasmas can be effective in compaction and destraction of liquid and solid hazardous wastes (Watanabe, 2003), including treatment of radioactive wastes by plasma incineration and vitrification for final disposal (Tzeng et al., 1998), plasma compaction... 

RO preceded by MF or UF is considered as an option for the treatment of radioactive wastes from Romanian nuclear centers. Effective studies are carried out at Research Center for... 

A.27. Effluents. The inspection programme should include verification that any releases of effluents are within the authorized discharge limits. This should include the review of systems for the treatment of radioactive waste and for the monitoring of effluents. Training and qualifications for technicians and workers anployed in the areas concerned should also be reviewed. 

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