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Nuclear Energy
Published in Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff, Radiation and Radioactivity on Earth and Beyond, 2020
Ivan G. Draganić, Zorica D. Draganić, Jean-Pierre Adloff
There exists a fundamental approach to the problem that may provide a technical solution. At present, only three components are separated from the spent fuel: uranium, plutonium and a remaining fraction which includes all fission products, transuranium elements and radionuclides from cladding and reactor material. The storage of high-level wastes could be greatly facilitated if efficient separation of the transuranium elements from the bulk waste is achieved. Neptunium, americium, curium, and plutonium are all long-lived a-emitters which constitute a major potential hazard on a time scale greater than 1000 years. Once separated, the transuranium elements could be consumed in nuclear reactors and, at the same time, contribute to energy production as part of the fissile material.
Managing High-Level Radioactive Wastes
Published in Roland Pusch, Raymond N. Yong, Masashi Nakano, Geologic Disposal of High-Level Radioactive Waste, 2018
Roland Pusch, Raymond N. Yong, Masashi Nakano
Actinides are chemical elements with atomic numbers that range from 89 (actinium, Ac) to 103 (lawrencium, Lr). Absorption by 238U of some of the neutrons produced when 235U is fissioned in the reactor produces plutonium and various kinds of actinides. Transuranics are transuranium elements with atomic numbers greater than 92 (uranium)—except for Np and Pu, they are generally considered as synthetic elements since they are produced in the course of reactions in reactors or particle accelerators.
Properties of the Elements and Inorganic Compounds
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Nineteen isotopes of plutonium are now known. Plutonium has assumed the position of dominant importance among the transuranium elements because of its successful use as an explosive ingredient in nuclear weapons and the place it holds as a key material in the development of industrial use of nuclear power. One kilogram is equivalent to about 22 million kilowatt hours of heat energy. The complete detonation of a kilogram of plutonium produces an explosion equal to about 20,000 tons of chemical explosive. Its importance depends on the nuclear property of being readily fissionable with neutrons and its availability in quantity. The world's nuclear-power reactors are now producing about 20,000 kg of plutonium/yr. By 1982 it was estimated that about 300,000 kg had accumulated. The various nuclear applications of plutonium are well known. 238Pu has been used in the Apollo lunar missions to power seismic and other equipment on the lunar surface. As with neptunium and uranium, plutonium metal can be prepared by reduction of the trifluoride with alkaline-earth metals. The metal has a silvery appearance and takes on a yellow tarnish when slightly oxidized. It is chemically reactive. A relatively large piece of plutonium is warm to the touch because of the energy given off in alpha decay. Larger pieces will produce enough heat to boil water. The metal readily dissolves in concentrated hydrochloric acid, hydroiodic acid, or perchloric acid with formation of the Pu+3 ion. The metal exhibits six allotropic modifications having various crystalline structures. The densities of these vary from 16.00 to 19.86 g/cm3. Plutonium also exhibits four ionic valence states in aqueous solutions: Pu+3(blue lavender), Pu+4 (yellow brown), PuO+ (pink?), and PuO+2 (pink orange). The ion PuO+ is unstable in aqueous solutions, disproportionating into Pu+4 and PuO+2. The Pu+4 thus formed, however, oxidizes the PuO+ into PuO+2, itself being reduced to Pu+3, giving finally Pu+3 and PuO+2. Plutonium forms binary compounds with oxygen: PuO, PuO2, and intermediate oxides of variable composition; with the halides: PuF3, PuF4, PuCl3, PuBr3, PuI3; with carbon, nitrogen, and silicon: PuC, PuN, PuSi2. Oxyhalides are also well known: PuOCl, PuOBr, PuOI. Because of the high rate of emission of alpha particles and the element being specifically absorbed by bone marrow, plutonium, as well as all of the other transuranium elements except neptunium, are radiological poisons and must be handled with very special equipment and precautions. Plutonium is a very dangerous radiological hazard. Precautions must also be taken to prevent the unintentional formation of a critical mass. Plutonium in liquid solution is more likely to become critical than solid plutonium. The shape of the mass must also be considered where criticality is concerned. Plutonium-239 is available to authorized users from the O.R.N.L. at a cost of about $4.80/mg (99.9%) plus packing costs.
A new approach to radioactive waste self-burial using high penetrating radiation
Published in Journal of Nuclear Science and Technology, 2018
Rafael Arutunyan, Leonid Bolshov, Anton Shvedov
For the final disposal of waste containing transuranium elements, it is required to use deep disposal in geological formations [1]. Work on the development of such storage facilities is carried out in the world; there are known projects of Sweden (Oskarhamn, Aspo laboratory), Finland (Olkiluoto, ONKALO laboratory), USA (Nevada, Yucca Mountain), and others [2]. In Russia, a project for disposal of RW in the Nizhnekansk granitoid massif is being developed, and an underground research laboratory is planned in the near future. However, justifying the safety of such storage facilities for many years to come is a very difficult task and involves considerable uncertainties in the modeling of processes potentially leading to release of radionuclides into the environment.
Potential threat to human health during forest fires in the Belarusian exclusion zone
Published in Aerosol Science and Technology, 2018
Alexander A. Dvornik, Alexander M. Dvornik, Raisa A. Korol, Natalia V. Shamal, Sergey O. Gaponenko, Alesya V. Bardyukova
After 30 years since the accident at the Chernobyl Nuclear Power Plant, radioactive contamination in the 30-km Chernobyl zone is determined by long-lived radionuclides of 137Cs, and 90Sr (with the half-life time 30.1 and 29.1 years, respectively) and alpha-emitting isotopes of 238,239,240Pu and 241Am, also known as transuranium elements (Sokolik et al. 2004; Kashparov et al. 2003). The transuranium elements have a high toxicity and are especially harmful to internal exposure pathway through inhalation. This can cause a local irradiation of lung tissue, lymphatic knots, etc.
Microextractors applied in nuclear-spent fuel reprocessing: Micro/mini plants and radiochemical analysis
Published in Critical Reviews in Environmental Science and Technology, 2018
Tao Wang, Tingliang Xie, Cong Xu
Nuclear energy offers unparalleled advantages of high energy density, excellent operation stability, and low greenhouse gas emissions and is considered one of the most promising solutions to the energy crisis in the future (Collum, 2017). However, the spent fuel unloaded from nuclear reactors contains a large amount of hazardous radionuclides, including unexploited U, transuranium elements [neptunium (Np), plutonium (Pu), americium (Am), curium (Cm), etc.] in addition to various fission products (long-lived fission products: 129I, 99Tc, 93Zr, 135Cs; medium-lived fission products: 137Cs, 90Sr; short-lived fission products: 131I, 140Ba; stable isotopes: lanthanides or others). For example, the spent fuel unloaded from a light water reactor with a burn up of 50 GWd/tHM consists of 93.4% uranium (0.8% 235U), 5.2% fission products, 1.2% plutonium, and 0.2% minor transuranic elements (Np, Am, Cm). Taking into account potential vulnerability to nuclear terrorism, the environmental risk of radioactive wastes, and high costs, the United States choose a once-through strategy for the spent fuel. However, several European countries, Russia, China, and Japan have policies to reprocess the spent nuclear fuel to recover useful resources and reduce waste volumes. The fissionable and valuable uranium and plutonium are almost completely recovered from the spent fuel for recycling purposes. However, long-lived and highly radioactive radionuclides that remain in reprocessing wastes are potentially harmful to the environment and the humans. With the increasing nuclear energy capacity, these radiotoxic materials generated by reprocessing would become a potential safety hazard in the future, especially in countries with a large population density such as China and India.