Low-level nuclear wast

In 1980, Congress deterrnined that each state should be responsible for ensuring the proper handling and disposal of commercial low level nuclear wastes generated in their states. Regional disposal sites have also been estabHshed at BamweU, South Carolina, and Ward Valley, California. These wastes are handled by Hcensed disposal faciHties where they are packaged, placed in burial trenches, and covered with soil. Less than half of the low level nuclear waste produced annually in the United States comes from nuclear power plants. Low level nuclear power plant wastes include contaminated equipment. 

TBq (14,000 Ci) of reportedly low-level nuclear waste, concrete-encapsulated in at least 47,500 55-gallon 16-gauge steel drums (life-expectancy 30 year in sea water) (Suchanek et al. 1996). These were deposited at three sites 100, 900, and 1,800 m deep. 

Worldwide, there are numerous plasma system designs for treatment of all types of wastes. Economical considerations limit their commercial applications to the most profitable actions. Presently they commercially operate in Switzerland and Germany for low level nuclear waste vitrification, in France and the USA for asbestos waste vitrification, in the USA and Australia for hazardous waste treatment, in Japan and France for municipal fly ash vitrification. The most of installations is working in Japan because there 70% of municipal waste is incinerated and the ash can not be used as landfill. EU Regulations banning the disposal to landfill of toxic and hazardous wastes after year 2002 may cause wider use of plasma waste destruction technology in Europe. 

Stabilizes waste containing lead, mercury, cadmium, chromium, and low-level nuclear waste. 

The most usual route of waste classification is by radioactivity and thermal emission, mainly between high-level nuclear waste (HLNW) and low-level nuclear waste (LLNW). Depending on the countries there are other categories, such as intermediate-level nuclear waste (ILNW) and more recently another category has been introduced in order to avoid unnecessary saturation of LLNW repositories these are the so-called very low activity nuclear wastes (VLNW). 

LDH LEU LIBD LAW LET LILW LIP LLNL LLW LMA LMFBR LOI LREE L/S LTA LWR Layered double hydroxide Low enriched uranium Laser-induced breakdown detection Low-activity waste Linear energy transfer Low- and intermediate-level nuclear waste Lead-iron phosphate Lawrence Livermore National Laboratory Low-level nuclear waste Law of mass action Liquid-metal-cooled fast-breeder reactor Loss on ignition Light rare earth elements (La-Sm) Liquid-to-solid ratio (leachates) Low-temperature ashing Light water reactor... 

The second fact is that there are a number of satisfactory methods for solidifying high- or low-level nuclear wastes for permanent disposal. One system or another may be preferred for a specific situation, and there will undoubtedly be several schools of thought as to which one is best in each case. 

The principal metals present in low-level nuclear waste nitrates are Hg2+, Ru, in the form of a nitro complex, and CrO . They are contained in a 1.3 MNaOH solution. The laboratory version of the basic device for their separation and removal is the packed-bed electrode shown in Fig. 15.25. 

The experimentally determined dependence of the concentration of the various entities as a function of time is shown in Fig. 15.26. The catholyte and anolyte concentrate NaOH and HN03, respectively, using a membrane separator. A plan for the electrochemical treatment of low-level nuclear wastes is shown in Fig. 15.27. The considerable electricity costs of such processes could be compensated by the sale of HN03 and NaOH. The Ru might be commercially valuable for some purposes, but its use may be compromised by residual radioactivity. 

Fig. 15.27. A schematic of a possible plant for the electrochemical treatment of low-level nuclear waste. (Reprinted from J. O M. Bockris and J. Kim, J. Appl. Electrochem. 27 626, copyright 1997.)...

An electrochemical process for treating low-level nuclear wastes is in the laboratory stage and not yet engineered. It must be understood less as a solution to the hazards of the low-level nuclear products contained in nitrate solution than as a solution for the remediation of the huge quantities of nitrate stored at nuclear waste depositories. The economic viability of the electrochemical process for conversion of nitrates to NH3 and N2 depends on the commercial development of its by-products, NaOH and HN03. 

Toste, A.P. and Lechner-Fish, T.J., Organic digenesis in commercial, low-level nuclear wastes. Radioactive Waste Manage. Nucl. Fuel Cycle, 12, 291, 1989. 

Figure 2 Illustration of the solid phase extraction system involving the selective removal of Pb2+ from a matrix typically found in acidic high-level or low-level nuclear waste. Following selective removal of the Pb (Step 2), the column is washed to remove the solution remaining in the dead volume, and the Pb is eluted in highly purified form with a complexing agent such as citrate ion or ethylenediaminetetraacetic acid (EDTA)...

Low-level radioactive waste gives off small amounts of ionizing radiation, is usually generated in small quantities, and need only be safely stored for relatively short periods of time due to the half-lives of the radioisotopes involved. Low-level nuclear waste includes such things as contaminated laboratory clothing, cleaning equipment and supplies, medical waste that is radioactive, and discarded radioactive devices such as smoke detectors. It is only necessary to safely store this waste for periods of 100-500 years. Prior to about 1979, most waste of this type was sealed in steel drums and dumped into the ocean. Current procedures require that such waste be stored in steel drums and buried in secure sites under several feet of soil (Figure 13.14). 

Bockris JOM, Kim J (1997) Electrochemical treatment of low-level nuclear wastes. J Appl Electrochem 27 623-634... 

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