Radioactive waste, clean

Agency (EPA), which was established in 1970, the same year the first Clean Air Act was passed into law. In 1972 the Clean Water Act became law, and in 1973 the Endangered Species Act became law. Other important federal environmental legislation includes the Resource Consei vation and Recoveiy Act, passed in 1976 the Response, Compensation, and Liability Act of 1980 the Nuclear Waste Policy Acts of 1982 and 1987 and the Low-Level Radioactive Waste Policy Acts of 1980 and 1985. From 1980 to 2000 these environmental regulations, and the enforcement efforts of the EPA, have had a much greater impact on decisions made in the energy industiy than all the policy initiatives implemented by the DOE. 

Another application for adsorption of metal impurities is in the nuclear power industry. Radioactive cesium is one of the compounds that is difficult to remove from radioactive waste. This is because ordinary resins and zeolites do not effectively adsorb radioactive cesium. In 1997, lONSlV lE-911 crystalline silicotitan-ate (CST) ion exchangers were developed and effectively used to clean up radioactive wastes in the Melton Valley tanks at Oak Ridge [268, 269], CST was discovered [270] by researchers at Sandia National Laboratories and Texas A M University, with commercial manufacture carried out by UOP. 

This paper is concerned primarily with the application of chemistry to the control of radioactive waste products from the use of nuclear energy. As far as immediate effects are concerned, nuclear power from uranium is a particularly clean energy source (1). The radioactive waste prpducts are well contained within the used fuel bundles. Since some constituents of the radioactive wastes take almost a thousand years to decay to an innocuous level and a few persist for many millennia, e.g. we have to ensure... 

Environmental many clean-up sites form radioactive waste... 

Sediments in the Mississippi River were accidentally contaminated with a low-level radioactive waste material that leaked from a nuclear power plant on the river. Pore water concentrations of radioactive compounds were measured following the spill and found to be 10 g/m over a 2-mm depth. The water contamination was 30% radioactive cesium ( Cs), with a half-life of 30 years, and 70% radioactive cobalt ( °Co), with a half-life of 6 years. Objections by the local residents are preventing clean-up efforts because some professor at the local state university convinced them that dredging the sediments and placing them in a disposal facility downstream would expose the residents to still more radioactivity. The state has decided that the sediments should be capped with 10 cm of clay and needs a quick estimate of the diffusion of radioactive material through the clay cap (Figure E2.8.1). If the drinking water limit (10 g/m ) is reached at mid-depth in the cap, the state will increase its thickness. Will this occur ... 

Some zeolites have a strong affinity for particular cations. Clinoptilolite (HEU) is a naturally occurring zeolite which sequesters caesium, and is used by British Nuclear Fuels (BNFL) to remove Cs from radioactive waste, exchanging its own Na ions for the radioactive Cs cations. Similarly, zeolite A can be used to recover radioactive strontium. Zeolites were heavily used in the clean up operations after the Chernobyl and Three Mile Island incidents. 

Contaminated glassware should be kept separated from uncontaminated. Contaminated beakers and flasks are placed in the special sink or other container for washing. Clean and wash all equipment with soap and water immediately after the experiment has been completed. If water-insoluble materials are being used, the first washing should be done with an organic solvent such as acetone. Soak contaminated pipets in a container filled with water. All broken glassware is disposed of in the Solid Radioactive Waste container. 

Minor spills must be cleaned first with absorbent blotter paper and then thoroughly rinsed with water. Always wear gloves during cleanup. Dispose of the blotter paper in the Solid Radioactive Waste container. The spill area should then be checked with a portable G-M counter. 

Harmful chemical spills can often be cleaned up by treatment with another chemical. A spill of H2SO4, for example, can be neutralized by adding NaHC03. Why can t harmful radioactive wastes from nuclear power plants be cleaned up just as easily ... 

EDTA has been determined in a wide variety of sample matrices by HPLC. These matrices include waste waters, natural waters, sediments, fertilizers, chemical cleaning solutions, radioactive waste solutions, and pharmaceutical preparations. Chinnick reported the separation and identification of EDTA and other aminopolycarboxylic acid sequestrants by a high performance liquid chromatographic (HPLC) method [57]. 

Nuclear fusion does not require uranium fuel and does not produce radioactive waste, and has no risk of explosive radiation-releasing accidents, but it takes place at a temperature of several million degrees. Nuclear fusion occurs in the sun, its fuel is hydrogen and, as such, it is an inexhaustible and a clean energy source. The problem with this technology is that, because it operates at several million degrees of temperature, its development is extremely expensive, and it will take at least until 2050 before the first fusion power plant can be built (Tokomak fusion test reactors). It is estimated that it will be 50 times more expensive than a regular power plant, and its safety is unpredictable. In short, the only safe and inexpensive fusion reactor is the Sun ... 

In radioactive waste treatment, significant operational aspects include the following. Since the operation requires the use of high pressures, there is a need to ensure control of the activity release from possible leaks. As with evaporation, pretreatment of the feed may be necessary to prevent scaling, and where dirty waters are to be fed directly it would be advisable to consider the use of equipment with larger membrane flow channels, which would permit periodic foam ball cleaning of the membrane surface. 

The RO process was implemented at the Institute of Atomic Energy, Swierk. The wastes collected there, from all users of nuclear materials in Poland, have to be processed before safe disposal. Until 1990 the wastes were treated by chemical methods that sometimes did not ensure sufficient decontamination. To reach the discharge standards the system of radioactive waste treatment was modernized. A new evaporator integrated with membrane installation replaced old technology based on chemical precipitation with sorption on inorganic sorbents. Two installations, EV and 3RO, can operate simultaneously or separately. The membrane plant is applied for initial concentration of the waste before the evaporator. It may be also used for final cleaning of the distillate, depending on actual needs. The need for additional distillate purification is necessitated due to entrainment of radionuclides with droplets or with the volatile radioactive compounds, which are carried over. 

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]. 

Evaporation is a widely used method for radioactive waste processing. One of disadvantages of the process is radionuclides carry over with small droplets. The contaminated condensate needs additional polishing with ion-exchange resins. The installation of MD module for final cleaning of the condensate can avoid the use of ion exchange. The unit that plays the role of demister can be driven with waste heat from nuclear power plant. 

The elaboration of proper pretreatment methods, application of antisealants, and minimization of secondary wastes created during cleaning cycles are of great importance. At present the research work on use of pressure-driven processes for radioactive waste treatment is focused on following issues ... 

Despite of some technical and process limitations, membrane techniques are very useful methods for the treatment of different types of effluents. They can be applied in nuclear centers processing low- and intermediate-level liquid radioactive wastes or in fuel reprocessing plants. All the methods reported in the chapter have many advantages and can be easily adapted for actual, specific needs. Some of them are good pretreatment methods the other can be used separately as final cleaning steps, or can be integrated with other processes. Membrane methods can supplement or replace techniques of distillation, extraction, adsorption, ion exchange, etc. Evaluation of membrane processes employed for liquid radioactive waste treatment is presented in Table 30.17. 

The costs of dealing with the reactors radioactive waste are estimated at 58 billion according to the Department of Energy. The costs of decommissioning, the tear down and clean up of old nuclear plants is also high. 

In Germany in 1938, Otto Hahn and Fritz Strassmann, skeptical of claims by Enrico Fermi and Irene Johot-Curie that bombardment of uranium by neutrons produced new so-called transuranic elements (elements beyond uranium), repeated these experiments and chemically isolated a radioactive isotope of barium. Unable to interpret these findings, Hahn asked Lise Meitner, a physicist and former colleague, to propose an explanation for his observations. Meitner and her nephew, Otto Frisch, showed that it was possible for the uranium nucleus to be spfit into two smaller nuclei by the neutrons, a process that they termed fission. The discovery of nuclear fission eventually led to the development of nuclear weapons and, after World War II, the advent of nuclear power to generate electricity. Nuclear chemists were involved in the chemical purification of plutonium obtained from uranium targets that had been irradiated in reactors. They also developed chemical separation techniques to isolate radioactive isotopes for industrial and medical uses from the fission products wastes associated with plutonium production for weapons. Today, many of these same chemical separation techniques are being used by nuclear chemists to clean up radioactive wastes resulting from the fifty-year production of nuclear weapons and to treat wastes derived from the production of nuclear power. 

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