Low-level radioactivity

Classification of wastes may be according to purpose, distinguishing between defense waste related to military appHcations, and commercial waste related to civiUan appHcations. Classification may also be by the type of waste, ie, mill tailings, high level radioactive waste (HLW), spent fuel, low level radioactive waste (LLW), or transuranic waste (TRU). Alternatively, the radionucHdes and the degree of radioactivity can define the waste. Surveys of nuclear waste management (1,2) and more technical information (3—5) are available. 

Nuclear utiUties have sharply reduced the volume of low level radioactive waste over the years. In addition to treating wastes, utiUties avoid contamination of bulk material by limiting the contact with radioactive materials. Decontamination of used equipment and materials is also carried out. For example, lead used for shielding can be successfully decontaminated and recycled using an abrasive mixture of low pressure air, water, and alumina. 

Fig. 2. Volume of low level radioactive waste per U.S. nuclear power reactor (weighted industry median). The decrease over the period 1980—1994 was...

Concerns over safe handling of radioactive materials and issues around the cost and disposal of low level radioactive waste has stimulated the development of nonradiometric products and technologies with the aim of replacing radioactive tracers in research and medical diagnosis (25). However, for many of the appHcations described, radioactive tracer technology is expected to continue to be widely used because of its sensitivity and specificity when compared with colorimetric, fluorescent, or chemiluminescent detection methods. 

Sulfur polymer cement shows promise as an encapsulation and stabilization agent for use with low level radioactive and mixed wastes. Use of SPC allows accommodation of larger percentages of waste than PCC. As of this writing (1997), SPC-treated waste forms have met requirements of both the Nuclear Regulatory Commission (NRC) and the Environmental Protection Agency (EPA). 

Cyclopentadiene oligomers have been formed by vapor deposition of CPD on kaolin to afford a sorbant for removal of oil from water (71). They are also employed as coatings for controlling release rates of fertilizers (72). Thermal addition of sulfur to a mixture of DCPD and CPD oligomers has led to a number of beneficial appHcations such as waste water oil adsorbant powdery foams (73), plasticized backing for carpets and artificial turfs (74), and in modified sulfur cements for encapsulating low-level radioactive wastes (75). 

Applicability Limitation Vitrification was originally tested as a means of solidification/immobilization of low level radioactive materials. It may also be useful for forming barrier walls. This latter use needs testing and evaluation to determine how uniform the wall would be and to evaluate the stability of the material over a period of time. 

The regulation of transport of discharges of low-level radioactive waste... 

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. 

The Hanford Nuclear Reservation in eastern Washington stores class A low-level radioactive waste. tCorbis... 

Low level waste from commercial facilities is buried on site. The Nuclear Regulatory Commission (NRC) has projected the activities and volumes of low level radioactive waste from all sources buried at commercial sites to the year 2000 using information from the Idaho National Environmental and Engineering Laboratory (INEEL) waste retrieval project and assuming that the waste disposal practices then used would continue into the future. The 20-year decayed 241Am and 243Am concentrations were estimated to be 380 and 230 pCi/m3 (14 and 8.5 Bq/m3), respectively (Kennedy et al. 1985). 

EPA. 2001d. Radioactive waste disposal An environmental perspective. Low-level radioactive waste. U.S. Environmental Protection Agency, http //www.epa.gov/radiation/radwaste/llw.htm. March 13, 2001. 

Kennedy WE, Cadwell LL, McKenzie DH. 1985. Biotic transport of radionuclides from a low-level radioactive waste site. Health Phys 49(1) 11-24. 

Francis AJ, Iden CR, Nine BJ, et al. 1980. Characterization of organics in leachates from low-level radioactive waste disposal sites. Nuclear Technol 50 158-163. 

Cadwell, L.L., R.G. Schreckhise, and R.E. Fitzner. 1979. Cesium-137 in coots (Fulica americana) on Hanford waste ponds contribution to population dose and offsite transport estimates. Pages 485-491 in Low-Level Radioactive Waste Management Proceedings of Health Physics Society. Twelfth Midyear Topical Symposium. February 11-15, 1979, Williamsburg, VA. 

Plasma gasification is a generic-type process that can accommodate virtually any input waste material in as-received condition, including liquids, gases, and solids in any form or combination. Also, moisture content is not a problem. Liquids, gases, and small particle-size waste materials are very easily and efficiently processed. Bulky items, such as household appliances, tires, and bedsprings, can also be readily accommodated without loss of destruction efficiency. The reactor vessel and waste feed mechanism are designed for the physical characteristics of the input waste stream. Even waste materials such as low-level radioactive waste can be processed to reduce the bulk and encapsulate the radioactive constituents to reduce leachability. 

Low-level radioactive waste (LLW), 25 851. See also Low level wastes (LLW) disposal of, 25 857-859 medical/biological, 25 865-866 storage of, 25 855 treatment of, 25 853 Low-level radioactive waste disposal facility, operation of, 25 858 Low-Level Radioactive Waste Policy Act of 1980, 25 852... 

Low level wastes (LLW), 23 592. See also Low-level radioactive waste (LLW) from reactors, 77 598 Low-melting lead alloys, 14 779 Low-melting-point indium alloys, 14 196 Low-melting thiodiols, DBTDL-catalyzed step-growth solution and melt polymerization reaction of, 23 744 Low-methoxyl pectins (LM pectins), 4 728 13 69... 

Accelerator mass spectrometry Instrumental technique for direct enumeration of low-level radioactive nuclides. 

Hazardous waste Dental clinics, chemotherapy wastes (some) listed as hazardous by USEPA, and low-level radioactive waste. 

Adsorbents for water and gas purification and for low level radioactive waste decontamination... 

Owing to their high surface area and affinity for many ions, Fe oxides are used in water treatment processes (see Chap. 21). Coprecipitation of radionuclides with Fe oxides at pH > 10 can be used to decontaminate low level, radioactive waste. 

High concentration of nontargeted ionic contaminants may reduce the efficiency of the 3M Empore extraction disk. Due to the high loading capabilities of the Empore membranes, the radionuclide concentration on the filters must be monitored to ensure that the membranes do not exceed the limits for low-level radioactive waste. 

Ceramicrete is an ex situ stabilization technology that uses chemically bonded phosphate ceramics to stabilize low-level radioactive waste and hazardous waste containing radionuclides and heavy metals. The technology mixes phosphates with acidic solution, causing an exothermic reaction similar to that used in forming concrete. But while concrete is based on relatively weak hydrogen and van der Waals bonding, Ceramicrete uses a combination of ionic, covalenf and van der Waals bonds to stabilize contaminants. 

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