Nuclear waste processing plants

Scientists at PNNL have developed an automated radiochemical sample preparation-separation-detection system for the determination of total "Tc in nuclear-waste process streams.46 85 86 144145 This analyzer was designed to support a technetium removal process planned as part of the development of a nuclear-waste processing plant. The process stream composition is both complex and variable, with a high pH, high salt matrix. Depending on the source of the feed, the total base content, the concentration of organics, and complexant concentrations will vary, as will the aluminum, nitrate, nitrite, dichromate, and radionuclide composition. 

Zeolite Selective Catafytic Reduction Catafysts for NOjp Removal from Nuclear Waste Processing Plants... 

NOx (typically 1-3%), present in the stack gas of nuclear waste process plants, is removed in die WINCO Process by two primary reactors to 300-1000 ppm by selective catalytic reduction (SCR) with NH3 over a commercial zeolite catalyst at 300-500°C followed by reduction to low ppm levels in a third cleanup reactor. This study involved laboratory tests on advanced SCR zeolite catalysts, NC-301, ZNX, and Cu-ZSM-5, for the primary SCR reactors over a range of anticipated process conditions using gas mixtures containing 500-5000 ppm NO+NO2, 500-5000 ppm NH3, 1-2% CO, 14% O2, and 20% steam in He. All three catalysts have acceptable levels of performance, i.e. selectively reduce >80% the NOx with NH3 to N2 over the temperature range of 400-500°C at a space velocity of 30,000 h- The Cu-ZSM-5 catalyst is the most active and selective catalyst converting >95% NOx d NH3 (at 500 - 5000 ppm of each) to N2. 

CONSTRUCTION OF THE LARGEST NUCLEAR-WASTE PROCESSING PLANT IN THE UNITED STATES... 

Waste from factories. Waste liquid from some factories gets dumped straight into rivers. This waste may contain dangerous substances such as mercury or its compoimds. These do not kill fish, but get stored up in their bodies and eventually poison humans. Hair drops out and teeth rot. The victim becomes irritable and twitchy, and will die if not treated. Lead is another poisonous metal. It could leak out from factories that make car batteries, for example. But even more dangerous is the radioactive waste that may leak from nuclear waste processing plants, or nuclear power stations. 

An interesting application of emissions control catalysts occurs in management and inmiobilization of spent radioactive fuels and wastes in the nuclear industry. During nuclear waste processing (NWP) at the Idaho Chemical Processing Plant (ICPP) NOx (NO and NO2) and CO pollutants are typically discharged at levels of 1-3% to a waste gas stream. It is necessary to control both NOx CO emissions in order to comply with current and anticipated regulatory requirements. 

Nuclear reactors or waste-processing plants like Sellafield in England [29]. 

ESTER A batch process for immobilizing nuclear waste in a borosilicate glass for longterm disposal. Developed in Italy in the 1970s and installed at the Euratom Research Centre, Ispra, in 1981. Intended for use in the radioactive pilot plant (Tmpianto Vetrificatione Eurex, IVEX) at the European Extraction Plant (UREX) at Saluggia, Italy. 

WIP [Waste Immobilization Plant] A process for immobilizing nuclear waste by incorporation in a borosilicate glass for long-term disposal. Developed in the 1970s in India for use at the waste immobilization plant at Tarapur. 

Neptunium-237 is obtained as a by-product of making plutonium from uranium isotopes in nuclear reactors. Significant amounts of this element may be recovered from plutonium plant nuclear wastes. Both the recovery and purification of neptunium can be carried out by various chemical processes, including precipitation, solvent extraction and ion exchange. 

Over 5001 of HLW have been vitrified in France and Germany. In the USA, the HLW at the Nuclear Fuel Services plant in West Valley Plant, New York, have been vitrified (300 two-ton canisters) and vitrification is ongoing at the Defense Waste Processing Facility (DWPF) at Savannah River, South Carolina 1600 canisters by February 2004). A vitrification plant is under construction at Hanford, Washington. Vitrification of all of the HLW in the USA will generate approximately 20 000 canisters, which are destined for disposal at the geological repository at Yucca Mountain. 

Nuclear power plants are used to generate electricity. At present there are more than 400 nuclear power plants operating all around the world. About 100 of them are in the United States and 200 are in Europe. The advantage of nuclear power is that no carbon-based pollutants are emitted as with the burning of fossil fuels. Flowever, the disadvantage is that the process produces nuclear wastes. Some... 

AVH [Atelier de Vitrification de la Hague] A process for immobilizing nuclear waste, operated at La Hague, France, based on the earlier AVM process. Used also in the THORP nuclear reprocessing plant at Sellafield, UK. 

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