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Advanced Fission Technologies and Systems
Published in William J. Nuttall, Nuclear Renaissance, 2022
The components of nuclear waste that are of the greatest long-term concern because of radiological toxicity are: the ‘minor actinides’ such as curium-242 and -245, americium-241, neptunium-237, etc. andthe ‘long-lived fission products’ such as iodine-129, caesium-135, selenium-79, radon-226 and technetium-99.
Energy and Environment
Published in T.M. Aggarwal, Environmental Control in Thermal Power Plants, 2021
High-level radioactive waste management concerns management and disposal of highly radioactive materials created during production of nuclear power. The technical issues in accomplishing this are daunting, due to the extremely long periods radioactive wastes remain deadly to living organisms. Of particular concern are two long-lived fission products, Technetium-99 (half-life 220,000 years) and Iodine-129 (half-life 15.7 million years), which dominate spent nuclear fuel radioactivity after a few thousand years. The most troublesome transuranic elements in spent fuel are Neptunium-237 (half-life two million years) and Plutonium-239 (half-life 24,000 years). Consequently, high-level radioactive waste requires sophisticated treatment and management to successfully isolate it from the biosphere. This usually necessitates treatment, followed by a long-term management strategy involving permanent storage, disposal or transformation of the waste into a non-toxic form.
Chemical Aspects of Nuclear Processes
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
The nuclides produced in fission are radioactive and decay with emission of β-particles and γ-rays, producing other radionuclides. All radioactive elements thus formed are called fission products. Their number is about 200 and their half-lives range from a fraction of a second to thousands of years. The long-lived fission products represent a large part of the radioactive wastes from nuclear power plants.
Reactor Physics Analysis Assessment of Feasibility of Using Advanced, Nonconventional Fuels in a Pressure Tube Heavy Water Reactor to Destroy Long-Lived Fission Products
Published in Nuclear Technology, 2021
The operation of nuclear reactors [including Generation 3+ (Gen-III+), Generation IV (Gen-IV), and Small Modular Reactor (SMR) technologies] produces high-level radioactive waste in the spent fuel, which contains numerous radioactive fission products, minor actinides (such as isotopes of Np, Pu, Am, Cm, and heavier elements). In addition, various radioactive isotopes are created in a nuclear reactor by neutron activation in structural components and in the coolant. Fortunately, many fission products have very short half-lives, ranging from seconds to less than a year, and will decay to relatively insignificant concentrations (similar to the radioactivity and radiotoxicity of natural uranium ore) in less than 10 years. Fission products such as 90Sr (Thalf-life ~ 29 years) and 137Cs (Thalf-life ~ 30 years) must be safely stored for at least 400 years [perhaps in a deep geological repository (DGR)] before they decay to less than 0.01% of their original level. In addition to minor actinides found in used nuclear fuel and the radioactive isotopes found in reactor structural components created by neutron activation, a key long-term problem for radioactive waste storage is the seven main long-lived fission products (LLFPs) listed in Table I, which have half-lives ranging from 100 000 years (for 126Sn) to 15 700 000 years (for 129I).
Estimation of uncertainty in transmutation rates of LLFPs in a fast reactor transmutation system via an estimation of the cross-section covariances
Published in Journal of Nuclear Science and Technology, 2021
Naoki Yamano, Tsunenori Inakura, Chikako Ishizuka, Satoshi Chiba
Long-lived fission products (LLFPs) are potential sources of radiation hazard upon long-term deep geological disposal of high-level radioactive waste due to their long half-lives, e.g., 79Se: 327,000 years, 93Zr: 1,610,000 years, 99Tc: 211,100 years, 107Pd: 6.5 million years, 129I: 15.7 million years, and 135Cs: 2.3 million years. Transmutation of minor actinides (MAs) is normally the primary goal of the separation-and-transmutation scenarios because they are considered as major elements in terms of long-term radiation hazard [1]. However, MAs are transmuted by fission reactions, which eventually produce fission products including LLFPs. Therefore, the transmutation of LLFPs is inevitably a matter to be considered seriously concerning a long-term risk in the groundwater scenario of deep geological repository [2,3].
Analysis on Transmutation of Long-Lived Fission Products from PWR Spent Fuel Using the 30-MW(thermal) RSG-GAS Reactor
Published in Nuclear Technology, 2020
M. Budi Setiawan, P. Made Udiyani, S. Kuntjoro, I. Husnayani, T. Surbakti
The world energy demand is growing remarkably. The electricity supply cannot be fulfilled by conventional power plants, such as oil, coal, and gas power plants, since these energy sources are limited and cannot be renewed. The solution to the problem of energy demand is nonconventional power plants, such as nuclear power plants (NPPs). NPPs have the advantage of requiring less fuel than conventional power plants, as well as operating with a single load of fuel for a long time of around 1.5 years so that the supply is not be affected by weather changes. However, an NPP has the challenge of radioactive waste. The radioactivity waste problem is the presence of radionuclides with high radioactivity, such as the minor actinides (MAs) of americium, curium, and neptunium. In addition, it also produces long-lived fission products (LLFPs) such as 99Tc, 129I, 93Zr, and 135Cs.