Radioactive nuclides pollutants

Cleaning of ground, including soils, from radioactive nuclide pollutants is another relevant problem. The electrokinetic method is the most efficient of the available methods of removing radioactive nuclides from the ground its application has two options—with and without flushing. 

In recent years, acute air pollution problems have been associated with large power plants. Stack discharges depend on the type of power plant. In oil-fired power plants, the emissions are mainly S02 and NOx. In coal-fired operations, emissions include S02, NOx and a variety of radioactive nuclides derived from coal. In nuclear power plants, emissions are limited to small amounts of radioactive fission products. 

The rewards of a workable nuclear fusion process would be great. Fusion produces neither the long-lived radioactive nuclides that accompany nuclear fission (although tritium requires care in handling) nor the environmental pollutants released by the burning of fossil fuels. Although deuterium is present in only 1/6000 of the abundance of ordinary hydrogen, its separation from the latter by the electrolysis of water is readily accomplished, and the oceans contain a virtually unlimited quantity of deuterium. 

The principal among radioactive materials are the following isotopes °Co, °Sr, °Y, ° Ru, Cs, Ce, Pm, 238,239,240py Ra, and so on. The groups of toxic radioactive elements are presented in Table 5.1. Approximately 95% of radioactive pollutants are concentrated in the upper soil layer. Individual radioactive nucUdes are present in the soil in different forms. Depending on the soil composition, 8%-30% of radioactive nuclides are present in exchange forms, 2%-10% of them are in water-soluble forms, and 60%-85% in tightly bounded forms (Table 5.2). 

Therefore, the problem of effective remediation of soils of radioactive nuclides is very relevant. Most technologies of soil decontamination that are currently developed are based on flushing soils with various chemicals and include processes of chemical leaching and selective extraction of radioactive nuclides (Prozorov et flZ., 2000 Shevtsova, 2003). The electrokinetic technique is a new and perspective method of soil remediation, whose main advantage consists in its applicability to decontaminating soils with low filtration ability directly at the site of its local pollution (e.g. in a rock mass) (Pamukcu and Wittle, 1992 Acar et al, 1993, 2001 Janosy and Piot, 1998 Korolev, 2001, 2006 Korolev, Barkhatova, and Shevtsova, 2007). 

Electrokinetic screens are applied for preventing radioactive nuclide diffusion from the pollution foci into the environment (groundwater, soil, and other subsurface materials), and they play the role of protective screens against possible migration of radioactive nuclides. Figures 5.1 and 5.2 show schemes of such electrokinetic... 

However, the protective properties of such screens deteriorate with time, and the screens themselves accumulate considerable amount of radioactive nuclides. Application of electrokinetic technology is very efficient for restoring the protective properties of such screens. Its application can help not only raise the sorption properties of a protective screen but also clean it from accumulated radioactive nuclides without extracting the polluted ground. 

The most efficient electrokinetic removal of radioactive nuclides from polluted ground can be achieved in combination with electrochemical leaching, that is, with... 

Electrokinetic technologies can be successfully applied for localization of radioactive pollution foci, cleaning polluted ground from radioactive nuclides, and restoring protective functions of sorption screens on the way of radioactive nucUde migration. Electromigration is fully assessed for the determination of the migration parameters of different radionuclides in soils. 

Nuclear-physical methods ai e the basic ones in controlling environmental pollution which results from nucleai -power complexes and power plants work. Oil and gas production leads to the extraction of radio nuclides of natural origin in considerable amounts, which later spread from oil-slimes and water wastes in the neighborhoods of oil and gas producing entei prises. Similaidy, toxic and radioactive elements can pollute environment in case of mineral deposits extraction. 

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