Plutonium disposal

Similar affinity of polonium and plutonium for marine surfaces implies that studies of the more easily measured polonium might be valuable in predicting some consequences of plutonium disposal in die oceans [8-11]. Rates at which plutonium and polonium deposit out of seawater onto surfaces of giant brown algae and inert surfaces, such as glass and cellulose, suggest that both nuclides are associated in coastal seawater with colloidal sized species having diffusivities of about 3 x 10"7 cm2/s. The parallel behaviour possibly... 

Most regulations focus on the time period up to 10" yr and 10 yr after emplacement when radioactivity is dominated by the decay of americium, neptunium, and plutonium. Disposal of nuclear waste in the US is regulated by the Environmental Protection Agency (EPA) and the Nuclear Regulatory Commission (NRC). There are several classes of nuclear waste each type is regulated by specific environmental regulations and each has a preferred disposal option, as described below. 

The Russian Federation (RF) Ministry of Health has made supplementary provisions to ensure the radiation safety of these operations. In a special RF Government Decree (1994), a comprehensive research and practical program titled Radiation Safety and Medico-Hygienic Provision of Operations on Dismantling Nuclear Weapons Including Plutonium Disposal (1994-1998) was approved. 

Thorium, uranium, and plutonium are well known for their role as the basic fuels (or sources of fuel) for the release of nuclear energy (5). The importance of the remainder of the actinide group Hes at present, for the most part, in the realm of pure research, but a number of practical appHcations are also known (6). The actinides present a storage-life problem in nuclear waste disposal and consideration is being given to separation methods for their recovery prior to disposal (see Waste treati nt, hazardous waste Nuclear reactors, waste managet nt). 

Nuclear wastes are classified according to the level of radioactivity. Low level wastes (LLW) from reactors arise primarily from the cooling water, either because of leakage from fuel or activation of impurities by neutron absorption. Most LLW will be disposed of in near-surface faciHties at various locations around the United States. Mixed wastes are those having both a ha2ardous and a radioactive component. Transuranic (TRU) waste containing plutonium comes from chemical processes related to nuclear weapons production. These are to be placed in underground salt deposits in New Mexico (see... 

Spent fuel can be stored or disposed of intact, in a once-through mode of operation, practiced by the U.S. commercial nuclear power industry. Alternatively, spent fuel can be reprocessed, ie, treated to separate the uranium, plutonium, and fission products, for re-use of the fuels (see Nuclear REACTORS, CHEMICAL reprocessing). In the United States reprocessing is carried out only for fuel from naval reactors. In the nuclear programs of some other countries, especially France and Japan, reprocessing is routine. 

The geologic aspects of waste disposal (24—26), proceedings of an annual conference on high level waste management (27), and one from an annual conference on all types of radioactive waste (28) are available. An alternative to burial is to store the spent fuel against a long-term future energy demand. Uranium and plutonium contained in the fuel would be readily extracted as needed. 

Transuranic Waste. Transuranic wastes (TRU) contain significant amounts (>3,700 Bq/g (100 nCi/g)) of plutonium. These wastes have accumulated from nuclear weapons production at sites such as Rocky Flats, Colorado. Experimental test of TRU disposal is planned for the Waste Isolation Pilot Plant (WIPP) site near Carlsbad, New Mexico. The geologic medium is rock salt, which has the abiUty to flow under pressure around waste containers, thus sealing them from water. Studies center on the stabiUty of stmctures and effects of small amounts of water within the repository. 

Management and Disposal of Excess Weapons Plutonium, National Academy Press, Washiagton, D.C., 1994. 

One energy source that first appeared to be highly attractive was nuclear power. The problem with nuclear power is that some costs were hidden in its initial development. Especially pernicious is the disposal of uranium oxide fuel after it has become depleted. It can be reprocessed, but at considerable expense, and the product plutonium can be used for weapons. In the United States the plan is to bui y... 

Now that much of the world has agreed to nuclear disarmament, scientists and world leaders are searching for uses for the surplus weapons-grade plutonium. Instead of pursuing disposal options, one option is the use of mixed-oxide (MOX) nuclear fuel. 

Other options for eliminating weapons-grade plutonium arc to seal it permanently in solid radioactive waste and dispose of it in waste repositories, and to use the plutonium to fuel fast neutron reactors (without reprocessing the plutonium into a MOX fuel). 

Nyhan JW, Drennon BJ, Abeele WV, et al. 1985. Distribution of plutonium and americium beneath a 33-yr old liquid waste disposal site. J Environ Qual 14(4) 501-509. 

The political problems with profound economic impact could include, for example, the significance of the continuing worldwide growth of nuclear power, with such issues as the use of Highly Enriched Uranium (HEU) and Plutonium obtained from tire dismantling of U.S. and former USSR nuclear weapons the urgency of nonproliferation the disposal of civilian and military nuclear waste nuclear power alternatives. 

U.S. cooperative efforts with Russia on plutonium disposition are premised on a two-track approach, including immobilization and burning as MOX in reactors. The 200 million recently appropriated by tbe U.S. Congress will help jump start the ongoing negotiations with Russia but, ultimately, more funding will be needed to create the necessary infrastructure in Russia to dispose of approximately 50 tons of surplus Russian plutonium, and eventually more as arms control progresses. 

While public understanding of nuclear issues may lack sophistication and is often based on inadequate or even misleading information, the public s assessments are not irrational. Having been told over many years that spent fuel is nuclear waste, it is only natural that the public should insist on its disposal. If and when effectively informed ofthe fact that spent fuel is not a waste but an energy resource, there is every reason to believe that the public will reject its deliberate burial and favor its storage under secure conditions, just as it now favors consuming, rather than immobilizing, surplus weapons plutonium. 

Another option is to use nuclear energy. Whereas technologically, with the development of breeder reactors, the uranium resources can be considered non-exhaustible and reactor technology can be considered safe [4] a serious concern is the proliferation of plutonium for nuclear weapons. There is also the unproven solution for disposal of radioactive material. 

Disposal of spent nuclear fuel and other radioactive wastes in the subsurface and assessment of the hazards associated with the potential release of these contaminants into the environment require knowledge of radionuclide geochemistry. Plutonium (Pu), for example, exhibits complex environmental chemistry understanding the mechanism of Pu oxidation and subsequent reduction, particularly by Mn-bearing minerals, is of major importance for predicting the fate of Pu in the subsurface. 

Subsurface contamination by uranium wastes and contaminant speciation during transport from a wastewater pond (originating from a plutonium production plant) to groundwater were studied by Catalano et al. (2006). Land disposal of basic sodium aluminates and acidic U(VI)-Cn(ll) and their redistribution in the vadose zone resulted in development of a groundwater nraninm plume. The solid phase speciation of nraninm from the base of the pond, throngh the subsurface, to the... 

Researchers claim that lonsiv TIE-96 can remove 99.9% of the plutonium, strontium, and cesium from waste solutions, allowing for wastes to be divided into separate low-level and high-level radioactive waste streams, where they can be safely and efficiently processed for disposal. 

Ewing, R. C., Weber, W. J. Lian, J. 2004. Nuclear waste disposal—pyrochlore (A2B2O7) Nuclear waste form for the immobilization of plutonium and minor actinides. Journal of Applied Physics, 95, 5949-5971. 

Merz, E. R. Walter, C. E. 1996. Disposal of Weapon Plutonium. Kluwer Academic Publishers, Amsterdam. 

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