A nuclear meltdown is a severe nuclear reactor accident that results in core damage from overheating. The term nuclear meltdown is not officially defined by the International Atomic Energy Agency or by the United States Nuclear Regulatory Commission. It has been defined to mean the accidental melting of the core of a nuclear reactor, however, and is in common usage a reference to the core's either complete or partial collapse.
The Atomic Age, also known as the Atomic Era, is the period of history following the detonation of the first nuclear weapon, The Gadget at the Trinity test in New Mexico, on 16 July 1945, during World War II. Although nuclear chain reactions had been hypothesized in 1933 and the first artificial self-sustaining nuclear chain reaction had taken place in December 1942, the Trinity test and the ensuing bombings of Hiroshima and Nagasaki that ended World War II represented the first large-scale use of nuclear technology and ushered in profound changes in sociopolitical thinking and the course of technological development.
The RBMK is a class of graphite-moderated nuclear power reactor designed and built by the Soviet Union. The name refers to its design where, instead of a large steel pressure vessel surrounding the entire core, the core is surrounded by a cylindrical annular steel tank inside a concrete vault and each fuel assembly is enclosed in an individual 8 cm (inner) diameter pipe. The channels also contain the coolant, and are surrounded by graphite.
A nuclear and radiation accident is defined by the International Atomic Energy Agency (IAEA) as "an event that has led to significant consequences to people, the environment or the facility." Examples include lethal effects to individuals, large radioactivity release to the environment, reactor core melt." The prime example of a "major nuclear accident" is one in which a reactor core is damaged and significant amounts of radioactive isotopes are released, such as in the Chernobyl disaster in 1986 and Fukushima nuclear disaster in 2011.
The Burj Khalifa is a skyscraper in Dubai, United Arab Emirates. It is the world's tallest structure. With a total height of 829.8 m and a roof height of 828 m (2,717 ft), the Burj Khalifa has been the tallest structure and building in the world since its topping out in 2009, surpassing Taipei 101, the previous holder of that status.
Tokyo Electric Power Company Holdings, Incorporated is a Japanese electric utility holding company servicing Japan's Kantō region, Yamanashi Prefecture, and the eastern portion of Shizuoka Prefecture. This area includes Tokyo. Its headquarters are located in Uchisaiwaicho, Chiyoda, Tokyo, and international branch offices exist in Washington, D.C., and London. It is a founding member of strategic consortiums related to energy innovation and research; such as JINED, INCJ and MAI.
The Chernobyl Nuclear Power Plant is a nuclear power plant undergoing decommissioning. ChNPP is located near the abandoned city of Pripyat in northern Ukraine, 16.5 kilometers (10 mi) northwest of the city of Chernobyl, 16 kilometers (10 mi) from the Belarus–Ukraine border, and about 100 kilometers (62 mi) north of Kyiv. The plant was cooled by an engineered pond, fed by the Pripyat River about 5 kilometers (3 mi) northwest from its juncture with the Dnieper.
A containment building is a reinforced steel, concrete or lead structure enclosing a nuclear reactor. It is designed, in any emergency, to contain the escape of radioactive steam or gas to a maximum pressure in the range of 275 to 550 kPa. The containment is the fourth and final barrier to radioactive release, the first being the fuel ceramic itself, the second being the metal fuel cladding tubes, the third being the reactor vessel and coolant system.
Nuclear energy policy is a national and international policy concerning some or all aspects of nuclear energy and the nuclear fuel cycle, such as uranium mining, ore concentration, conversion, enrichment for nuclear fuel, generating electricity by nuclear power, storing and reprocessing spent nuclear fuel, and disposal of radioactive waste. Nuclear energy policies often include the regulation of energy use and standards relating to the nuclear fuel cycle. Other measures include efficiency standards, safety regulations, emission standards, fiscal policies, and legislation on energy trading, transport of nuclear waste and contaminated materials, and their storage. Governments might subsidize nuclear energy and arrange international treaties and trade agreements about the import and export of nuclear technology, electricity, nuclear waste, and uranium.
The Chernobyl disaster began on 26 April 1986 with the explosion of the No. 4 reactor of the Chernobyl Nuclear Power Plant, near the city of Pripyat in the north of the Ukrainian SSR, close to the border with the Byelorussian 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 accident in Japan. The initial emergency response and subsequent mitigation efforts involved more than 500,000 personnel and cost an estimated 18 billion roubles—roughly US$68 billion in 2019, adjusted for inflation. It is considered the worst nuclear disaster in history.
A concrete pump is a machine used for transferring liquid concrete by pumping. There are different types of concrete pumps.
The Hamaoka Nuclear Power Plant is a nuclear power plant in the city of Omaezaki in Shizuoka Prefecture, on Japan's east coast, 200 km south-west of Tokyo. It is managed by the Chubu Electric Power Company. There are five units contained at a single site with a net area of 1.6 km2. The two oldest units were permanently shut down in 2009 and are currently being decommissioned. Three units Hamaoka-3, 4 and 5 are in long-term shutdown since the aftermath of the Fukushima accident in 2011. From 2011 to 2017 these units underwent significant safety upgrades to enhance their resistance against extreme environmental impacts such as earthquakes and tsunamis. In 2014, Chubu Electric submitted an application to resume power generation, but the review by the Nuclear Regulation Authority has been progressing slowly, and is still ongoing as of 2024. A sixth unit was proposed in 2008 but its construction has been deferred indefinitely.
Nuclear power has various environmental impacts, both positive and negative, including the construction and operation of the plant, the nuclear fuel cycle, and the effects of nuclear accidents. Nuclear power plants do not burn fossil fuels and so do not directly emit carbon dioxide. The carbon dioxide emitted during mining, enrichment, fabrication and transport of fuel is small when compared with the carbon dioxide emitted by fossil fuels of similar energy yield, however, these plants still produce other environmentally damaging wastes. Nuclear energy and renewable energy have reduced environmental costs by decreasing CO2 emissions resulting from energy consumption.
Anti-nuclear protests began on a small scale in the U.S. as early as 1946 in response to Operation Crossroads. Large scale anti-nuclear protests first emerged in the mid-1950s in Japan in the wake of the March 1954 Lucky Dragon Incident. August 1955 saw the first meeting of the World Conference against Atomic and Hydrogen Bombs, which had around 3,000 participants from Japan and other nations. Protests began in Britain in the late 1950s and early 1960s. In the United Kingdom, the first Aldermaston March, organised by the Campaign for Nuclear Disarmament, took place in 1958. In 1961, at the height of the Cold War, about 50,000 women brought together by Women Strike for Peace marched in 60 cities in the United States to demonstrate against nuclear weapons. In 1964, Peace Marches in several Australian capital cities featured "Ban the Bomb" placards.
Sany Heavy Industry Co., Ltd. is a Chinese multinational heavy equipment manufacturing company headquartered in Changsha, Hunan. It is the 3rd-largest heavy equipment manufacturer in the world, and the first in its industry in China to enter the FT Global 500 and the Forbes Global 2000 rankings. Its founder and main shareholder is Liang Wengen.
Fukushima Daiichi is a multi-reactor nuclear power site in the Fukushima Prefecture of Japan. A nuclear disaster occurred there after a 9.0 magnitude earthquake and subsequent tsunami on 11 March 2011. The earthquake triggered a scram shut down of the three active reactors, and the ensuing tsunami crippled the site, stopped the backup diesel generators, and caused a station blackout. The subsequent lack of cooling led to explosions and meltdowns, with problems at three of the six reactors and in one of the six spent-fuel pools.
The nuclear energy policy of the United States began in 1954 and continued with the ongoing building of nuclear power plants, the enactment of numerous pieces of legislation such as the Energy Reorganization Act of 1974, and the implementation of countless policies which have guided the Nuclear Regulatory Commission and the Department of Energy in the regulation and growth of nuclear energy companies. This includes, but is not limited to, regulations of nuclear facilities, waste storage, decommissioning of weapons-grade materials, uranium mining, and funding for nuclear companies, along with an increase in power plant building. Both legislation and bureaucratic regulations of nuclear energy in the United States have been shaped by scientific research, private industries' wishes, and public opinion, which has shifted over time and as a result of different nuclear disasters.
To date, the nuclear accidents at the Chernobyl (1986) and Fukushima Daiichi (2011) nuclear power plants, are the only INES level 7 nuclear accidents.
The Fukushima disaster cleanup is an ongoing attempt to limit radioactive contamination from the three nuclear reactors involved in the Fukushima Daiichi nuclear disaster that followed the earthquake and tsunami on 11 March 2011. The affected reactors were adjacent to one another and accident management was made much more difficult because of the number of simultaneous hazards concentrated in a small area. Failure of emergency power following the tsunami resulted in loss of coolant from each reactor, hydrogen explosions damaging the reactor buildings, and water draining from open-air spent fuel pools. Plant workers were put in the position of trying to cope simultaneously with core meltdowns at three reactors and exposed fuel pools at three units.
Long one of the world's most committed promoters of civilian nuclear power, Japan's nuclear industry was not hit as hard by the effects of the 1979 Three Mile Island accident (USA) or the 1986 Chernobyl disaster (USSR) as some other countries. Construction of new plants continued to be strong through the 1980s and into the 1990s. However, starting in the mid-1990s there were several nuclear related accidents and cover-ups in Japan that eroded public perception of the industry, resulting in protests and resistance to new plants. These accidents included the Tokaimura nuclear accident, the Mihama steam explosion, cover-ups after accidents at the Monju reactor, and the 21 month shut down of the Kashiwazaki-Kariwa Nuclear Power Plant following an earthquake in 2007. Because of these events, Japan's nuclear industry has been scrutinized by the general public of the country.
