Spent fuel storage at power plant sites is considered temporary, with the ultimate goal being permanent disposal. Therefore there is no pressing safety or security reason to mandate earlier transfer of fuel from pool to cask. The NRC believes spent fuel pools and dry casks both provide adequate protection for public health and safety and the environment. The certifications and licenses can be renewed. The NRC certifies cask designs and licenses dry cask storage facilities for up to 40 years. NRC has authorized transfer as early as three years the industry norm is about 10 years. Fuel is typically cooled at least five years in the pool before transfer to cask. These casks are stainless steel canisters surrounded by concrete. The water is typically about 40 feet deep and serves both to shield the radiation and cool the rods.Īs the pools near capacity, utilities move some of the older spent fuel into "dry cask" storage. nuclear power plants store spent nuclear fuel in "spent fuel pools." These pools are made of reinforced concrete several feet thick, with steel liners. There is no commercial reprocessing of nuclear power fuel in the United States at present almost all existing commercial high-level waste is unreprocessed spent fuel.Īll U.S. A small amount of liquid high-level waste was generated from reprocessing commercial power reactor fuel in the 1960s and early 1970s. Most of the high-level waste (other than spent fuel) generated over the last 35 years has come from reprocessing fuel from government-owned plutonium production reactors and from naval, research and test reactors. The uranium and plutonium can be used again as fuel. Reprocessing separates residual uranium and plutonium from the fission products. The dose produced through this indirect exposure would be much smaller than a direct-exposure dose, but a much larger population could be exposed. If isotopes from these high-level wastes get into groundwater or rivers, they may enter food chains. For example, 10 years after removal from a reactor, the surface dose rate for a typical spent fuel assembly exceeds 10,000 rem/hour – far greater than the fatal whole-body dose for humans of about 500 rem received all at once. High-level wastes are hazardous because they produce fatal radiation doses during short periods of direct exposure. Plutonium-239 has a half-life of 24,000 years. Strontium-90 and cesium-137 have half-lives of about 30 years (half the radioactivity will decay in 30 years). Some isotopes decay in hours or even minutes, but others decay very slowly. Radioactive isotopes eventually decay, or disintegrate, to harmless materials. Transuranic wastes, sometimes called TRU, account for most of the radioactive hazard remaining in high-level waste after 1,000 years. These heavier-than-uranium, or "transuranic," elements do not produce nearly the amount of heat or penetrating radiation that fission products do, but they take much longer to decay. These atoms form heavier elements such as plutonium. Second, some uranium atoms capture neutrons produced during fission. These isotopes, called "fission products," account for most of the heat and penetrating radiation in high-level waste. The fission creates radioactive isotopes of lighter elements such as cesium-137 and strontium-90. First, uranium atoms split, creating energy that is used to produce electricity. Before these fuel rods are used, they are only slightly radioactive and may be handled without special shielding.ĭuring the fission process, two things happen to the uranium in the fuel. Nuclear reactor fuel contains ceramic pellets of uranium-235 inside of metal rods. Spent fuel is thermally hot as well as highly radioactive and requires remote handling and shielding. High-level radioactive waste primarily is uranium fuel that has been used in a nuclear power reactor and is "spent," or no longer efficient in producing electricity. Regulations establish minimum acceptable performance criteria for licensees managing wastes, while providing for flexibility in technological approach. The NRC also regulates high-level wastes generated by the Department of Energy that are subject to long-term storage and not used for, or part of, research and development activities. The NRC regulates the storage and disposal of all commercially generated radioactive wastes in the United States. Low-level waste comes from reactor operations and from medical, academic, industrial and other commercial uses of radioactive materials. High-level waste is primarily spent fuel removed from reactors after producing electricity. There are two broad classifications: high-level or low-level waste. Radioactive waste is also generated while decommissioning and dismantling nuclear reactors and other nuclear facilities. Radioactive (or nuclear) waste is a byproduct from nuclear reactors, fuel processing plants, hospitals and research facilities. Responsibilities of Other Government Agencies.
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