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Nuclear Entombment
Nuclear entombment (also referred to as "safe enclosure") is a method of nuclear decommissioning in which radioactive contaminants are encased in a structurally long-lived material, such as concrete. This prevents radioactive material and other contaminated substances from being exposed to human activity and the environment. Entombment is usually applied to nuclear reactors, but also some nuclear test sites. Nuclear entombment is the least used of three methods for decommissioning nuclear power plants, the others being dismantling and safe enclosure. The use of nuclear entombment is more practical for larger nuclear power plants that are in need of both long and short term burials, as well as for power plants which seek to terminate their facility licenses. Entombment is used on a case by case basis because of its major commitment with years of surveillance and complexity until the radioactivity is no longer a major concern, permitting decommissioning and ultimate unrestricted relea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Decommissioning
Nuclear decommissioning is the process whereby a nuclear facility is dismantled to the point that it no longer requires measures for radiation protection. The presence of radioactive material necessitates processes that are potentially occupationally hazardous, expensive, time-intensive, and present environmental risks that must be addressed to ensure radioactive materials are either transported elsewhere for storage or stored on-site in a safe manner.Benjamin K. Sovacool. "A Critical Evaluation of Nuclear Power and Renewable Electricity in Asia", ''Journal of Contemporary Asia'', Vol. 40, No. 3, August 2010, p. 373. The challenge in nuclear decommissioning is not just technical, but also economical and social. Decommissioning is an administrative and technical process. It includes clean-up of radioactive materials and progressive demolition of the facility. Once a facility is fully decommissioned, no radiological danger should persist. The costs of decommissioning are gene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
USNRC
The Nuclear Regulatory Commission (NRC) is an independent agency of the United States government tasked with protecting public health and safety related to nuclear energy. Established by the Energy Reorganization Act of 1974, the NRC began operations on January 19, 1975, as one of two successor agencies to the United States Atomic Energy Commission. Its functions include overseeing reactor safety and security, administering reactor licensing and renewal, licensing radioactive materials, radionuclide safety, and managing the storage, security, recycling, and disposal of spent fuel. History Prior to 1975 the Atomic Energy Commission was in charge of matters regarding radionuclides. The AEC was dissolved, because it was perceived as unduly favoring the industry it was charged with regulating.John Byrne and Steven M. Hoffman (1996). ''Governing the Atom: The Politics of Risk'', Transaction Publishers, p. 163. The NRC was formed as an independent commission to oversee nuclear en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Power Stations
A nuclear power plant (NPP) is a thermal power station in which the heat source is a nuclear reactor. As is typical of thermal power stations, heat is used to generate steam that drives a steam turbine connected to a generator that produces electricity. , the International Atomic Energy Agency reported there were 422 nuclear power reactors in operation in 32 countries around the world, and 57 nuclear power reactors under construction. Nuclear plants are very often used for base load since their operations, maintenance, and fuel costs are at the lower end of the spectrum of costs. However, building a nuclear power plant often spans five to ten years, which can accrue to significant financial costs, depending on how the initial investments are financed. Nuclear power plants have a carbon footprint comparable to that of renewable energy such as solar farms and wind farms, and much lower than fossil fuels such as natural gas and brown coal. Despite some spectacular catas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Technology
Nuclear technology is technology that involves the nuclear reactions of atomic nuclei. Among the notable nuclear technologies are nuclear reactors, nuclear medicine and nuclear weapons. It is also used, among other things, in smoke detectors and gun sights. History and scientific background Discovery The vast majority of common, natural phenomena on Earth only involve gravity and electromagnetism, and not nuclear reactions. This is because atomic nuclei are generally kept apart because they contain positive electrical charges and therefore repel each other. In 1896, Henri Becquerel was investigating phosphorescence in uranium salts when he discovered a new phenomenon which came to be called radioactivity. He, Pierre Curie and Marie Curie began investigating the phenomenon. In the process, they isolated the element radium, which is highly radioactive. They discovered that radioactive materials produce intense, penetrating rays of three distinct sorts, which they labeled al ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Decommissioning Authority
The Nuclear Decommissioning Authority (NDA) is a non-departmental public body of the Department for Business, Energy and Industrial Strategy, formed by the Energy Act 2004. It evolved from the Coal and Nuclear Liabilities Unit of the Department of Trade and Industry. It came into existence during late 2004, and took on its main functions on 1 April 2005. Its purpose is to deliver the decommissioning and clean-up of the UK's civil nuclear legacy in a safe and cost-effective manner, and where possible to accelerate programmes of work that reduce hazard. The NDA does not directly manage the UK's nuclear sites. It oversees the work through contracts with specially designed companies known as site licence companies. The NDA determines the overall strategy and priorities for managing decommissioning. Although the NDA itself employs about 250 staff, its subsidiaries employ about 15,000 staff across the NDA estate. Its annual budget is £3.2billion, the vast majority of which is spent th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Runit Dome
Runit Island () is one of 40 islands of the Enewetak Atoll of the Marshall Islands in the Pacific Ocean. The island is the site of a radioactive waste repository left by the United States after it conducted a series of nuclear tests on Enewetak Atoll between 1946 and 1958. There are ongoing concerns around deterioration of the waste site and a potential radioactive spill. Runit Dome Construction The Runit Dome, also called Cactus Dome or locally , is a diameter, thick dome of concrete at sea level, encapsulating an estimated of radioactive debris, including some plutonium-239. The debris stems from nuclear tests conducted in the Enewetak Atoll by the United States between 1946 and 1958. From 1977 to 1980, loose waste and topsoil debris scraped off from six different islands in the Enewetak Atoll was transported here, mixed with concrete, and stored in the nuclear blast crater of the Cactus test from May 6, 1958. Four thousand US servicemen were involved in the cleanup and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dodewaard Nuclear Power Plant
Dodewaard nuclear power plant is a nuclear power plant with a boiling water reactor (BWR) of General Electric in the Dutch town of Dodewaard. The plant halted energy production in 1997. Its final decommissioning has been postponed for a period of 40 years and was placed into a safe enclosure configuration in 2005. History The plant in Dodewaard was the first nuclear power plant established in the Netherlands. It was built by the Dutch government, mainly as a means to obtain know-how about the construction and exploitation of a nuclear power plant. The plant was therefore relatively small with a net output of only 58 MW. Construction was started in 1965 and the facility opened on 26 March 1969, in the presence of Queen Juliana. After the Chernobyl disaster in 1986, the political tide turned against nuclear energy Nuclear energy may refer to: *Nuclear power, the use of sustained nuclear fission or nuclear fusion to generate heat and electricity * Nuclear binding en ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lucens Reactor
The Lucens reactor was a 6 MW experimental nuclear power reactor built next to Lucens, Vaud, Switzerland. After its connection to the electrical grid on 29 January 1968, the reactor only operated for a few months before it suffered an accident on 21 January 1969. The cause was a corrosion-induced loss of heat dispersal leading to the destruction of a pressure tube which caused an adjacent pressure tube to fail, and partial meltdown of the core, resulting in radioactive contamination of the cavern. Description In 1962 the construction of a Swiss-designed pilot nuclear power plant began. The heavy-water moderated, carbon dioxide gas-cooled reactor was built in a cavern. It produced 28 MW of heat, which was used to generate 6 MW of electricity, and it became critical 29 December 1966. It was fueled by 0.96% enriched uranium alloyed with chromium cased in magnesium alloy (magnesium with 0.6% zirconium) inserted into a graphite matrix. Carbon dioxide gas was pumped ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polycarbonate
Polycarbonates (PC) are a group of thermoplastic polymers containing carbonate groups in their chemical structures. Polycarbonates used in engineering are strong, tough materials, and some grades are optically transparent. They are easily worked, molded, and thermoformed. Because of these properties, polycarbonates find many applications. Polycarbonates do not have a unique resin identification code (RIC) and are identified as "Other", 7 on the RIC list. Products made from polycarbonate can contain the precursor monomer bisphenol A (BPA). Structure Carbonate esters have planar OC(OC)2 cores, which confers rigidity. The unique O=C bond is short (1.173 Å in the depicted example), while the C-O bonds are more ether-like (the bond distances of 1.326 Å for the example depicted). Polycarbonates received their name because they are polymers containing carbonate groups (−O−(C=O)−O−). A balance of useful features, including temperature resistance, impact resistance and o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chernobyl Disaster
The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the No. 4 reactor in the Chernobyl Nuclear Power Plant, near the city of Pripyat in the north of the Ukrainian SSR in the Soviet Union. It is one of only two nuclear energy accidents rated at seven—the maximum severity—on the International Nuclear Event Scale, the other being the 2011 Fukushima nuclear disaster in Japan. The initial emergency response, together with later decontamination of the environment, involved more than 500,000 personnel and cost an estimated 18 billion roubles—roughly US$68 billion in 2019, adjusted for inflation. The accident occurred during a safety test meant to measure the ability of the steam turbine to power the emergency feedwater pumps of an RBMK-type nuclear reactor in the event of a simultaneous loss of external power and major coolant leak. During a planned decrease of reactor power in preparation for the test, the operators accidentally dropp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Atomic Energy Act Of 1954
The Atomic Energy Act of 1954, 42 U.S.C. §§ 2011-2021, 2022-2286i, 2296a-2297h-13, is a United States federal law that covers for the development, regulation, and disposal of nuclear materials and facilities in the United States. It was an amendment to the Atomic Energy Act of 1946 and substantially refined certain aspects of the law, including increased support for the possibility of a civilian nuclear industry. Notably it made it possible for the government to allow private companies to gain technical information (Restricted Data) about nuclear energy production and the production of fissile materials, allowing for greater exchange of information with foreign nations as part of President Dwight D. Eisenhower's Atoms for Peace program, and reversed certain provisions in the 1946 law which had made it impossible to patent processes for generating nuclear energy or fissile materials. The H.R. 9757 legislation was passed by the 83rd U.S. Congressional session and signed into law ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-level Radioactive Waste Policy Of The United States
Radioactive waste is generated from the nuclear weapons program, commercial nuclear power, medical applications, and corporate and university-based research programs. Some of the materials LLW consists of are: "gloves and other protective clothing, glass and plastic laboratory supplies, machine parts and tools, and disposable medical items that have come in contact with radioactive materials". Waste is generally categorized as high level waste (HLW) and low-level waste (LLW). LLW contains materials such as irradiated tools, lab clothing, ion exchanger resins, animal carcasses, and trash from defense, commercial nuclear power, medical, and research activities. These materials usually have radioactivity that have short half lives—from ranges of multiple days to several hundred years. In 1990, 1.1 million cubic feet of LLW was produced. Currently, U.S. reactors generate about 40,000 cubic meters of low-level radioactive waste per year, including contaminated components and materials ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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