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Geomelting
GeoMelt is a process by which dangerous, contaminated material (such as radioactive waste and heavy metals) is mixed with clean soil, a blend of industrial minerals, and/or glass frit and melted to create an extremely hard and leach-resistant glass product. Vitrification immobilizes nearly all of the inorganic contaminants (i.e., radionuclides and heavy metals) present in the initial mixture by incorporation into the glass matrix. Organic wastes in the melt are destroyed by pyrolysis, and gaseous contaminants released during the melting process are treated separately. Developed in 1980 by the U.S. Department of Energy's Pacific Northwest National Laboratory (PNNL), the GeoMelt process is deployed in one of two ways: in-situ (in-place) treatment of buried radioactive and hazardous wastes, and In-Container Vitrification (ICV), which is ex-situ treatment where radioactive and hazardous wastes are vitrified in a refractory-lined steel container. Process Vitrification Geomelting is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vitrification
Vitrification (from Latin ''vitreum'', "glass" via French ''vitrifier'') is the full or partial transformation of a substance into a glass, that is to say, a non-crystalline amorphous solid. Glasses differ from liquids structurally and glasses possess a higher degree of connectivity with the same Hausdorff dimensionality of bonds as crystals: dimH = 3. In the production of ceramics, vitrification is responsible for its impermeability to water. Vitrification is usually achieved by heating materials until they liquidize, then cooling the liquid, often rapidly, so that it passes through the glass transition to form a glassy solid. Certain chemical reactions also result in glasses. In terms of chemistry, vitrification is characteristic for amorphous materials or disordered systems and occurs when bonding between elementary particles (atoms, molecules, forming blocks) becomes higher than a certain threshold value. Thermal fluctuations break the bonds; therefore, the low ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radioactive Waste
Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons reprocessing. The storage and disposal of radioactive waste is regulated by government agencies in order to protect human health and the environment. Radioactive waste is broadly classified into low-level waste (LLW), such as paper, rags, tools, clothing, which contain small amounts of mostly short-lived radioactivity, intermediate-level waste (ILW), which contains higher amounts of radioactivity and requires some shielding, and high-level waste (HLW), which is highly radioactive and hot due to decay heat, so requires cooling and shielding. In nuclear reprocessing plants about 96% of spent nuclear fuel is recycled back into uranium-based and mixed-oxide (MOX) fuels. The residual 4% is minor actinides and fission products the latter of w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wet Scrubber
The term wet scrubber describes a variety of devices that remove pollutants from a furnace flue gas or from other gas streams. In a wet scrubber, the polluted gas stream is brought into contact with the scrubbing liquid, by spraying it with the liquid, by forcing it through a pool of liquid, or by some other contact method, so as to remove the pollutants. Design The design of wet scrubbers or any air pollution control device depends on the industrial process conditions and the nature of the air pollutants involved. Inlet gas characteristics and dust properties (if particles are present) are of primary importance. Scrubbers can be designed to collect particulate matter and/or gaseous pollutants. The versatility of wet scrubbers allow them to be built in numerous configurations, all designed to provide good contact between the liquid and polluted gas stream. Wet scrubbers remove dust particles by ''capturing'' them in liquid droplets. The droplets are then collected, the liq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Environmental Impact Of Nuclear Power
Nuclear power has various environmental impacts, including the construction and operation of the plant, the nuclear fuel cycle, and the effects of nuclear accidents. Nuclear power plants do not burn fossil fuels and so do not directly emit carbon dioxide. The carbon dioxide emitted during mining, enrichment, fabrication and transport of fuel is small when compared with the carbon dioxide emitted by fossil fuels of similar energy yield, however, these plants still produce other environmentally damaging wastes. There is a "catastrophic risk" potential if containment fails, which in nuclear reactors can be brought about by overheated fuels melting and releasing large quantities of fission products into the environment. The most long-lived radioactive wastes, including spent nuclear fuel, must be contained and isolated for a long period of time. However, spent nuclear fuel can sometimes be reused, reducing the amount of waste. Emission of radioactivity from a nuclear plant is control ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
