The Three Mile Island accident was the partial meltdown of reactor number 2 of Three Mile Island Nuclear Generating Station (TMI-2) in Dauphin County, Pennsylvania, near Harrisburg and subsequent radiation leak that occurred on March 28, 1979. It was the most significant accident in U.S. commercial nuclear power plant history. The incident was rated a five on the seven-point International Nuclear Event Scale: Accident with wider consequences.
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 Nuclear Regulatory Commission. However, it has been defined to mean the accidental melting of the core of a nuclear reactor, and is in common usage a reference to the core's either complete or partial collapse.
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, radioactive isotope to the environment, or 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.
The H. B. Robinson Steam Electric Station, Unit 2 is a nuclear power station located near Hartsville, South Carolina. The plant consists of one Westinghouse 735 MW pressurized water reactor. The site once included a coal-fired unit that generated 174 MW and a combustion turbine unit that generated 15 MW.
Peach Bottom Atomic Power Station, a nuclear power plant, is located 50 miles (80 km) southeast of Harrisburg in Peach Bottom Township, York County, Pennsylvania, on the Susquehanna River three miles north of the Maryland border.
The Chernobyl disaster, also referred to as the Chernobyl accident, was a catastrophic nuclear accident. It occurred on 25–26 April 1986 in the No. 4 light water graphite moderated reactor at the Chernobyl Nuclear Power Plant near the now-abandoned town of Pripyat, in northern Ukrainian Soviet Socialist Republic, Soviet Union, approximately 104 km (65 mi) north of Kiev.
The Price-Anderson Nuclear Industries Indemnity Act is a United States federal law, first passed in 1957 and since renewed several times, which governs liability-related issues for all non-military nuclear facilities constructed in the United States before 2026. The main purpose of the Act is to partially compensate the nuclear industry against liability claims arising from nuclear incidents while still ensuring compensation coverage for the general public. The Act establishes a no fault insurance-type system in which the first approximately $12.6 billion is industry-funded as described in the Act. Any claims above the $12.6 billion would be covered by a Congressional mandate to retroactively increase nuclear utility liability or would be covered by the federal government. At the time of the Act's passing, it was considered necessary as an incentive for the private production of nuclear power — this was because electric utilities viewed the available liability coverage as inadequate.
The AP1000 is a nuclear power plant designed and sold by Westinghouse Electric Company. The plant is a pressurized water reactor with improved use of passive nuclear safety. The first AP1000 began operations in China at Sanmen Nuclear Power Station, where Unit 1 became the first AP1000 to achieve criticality in June 2018.
NUREG-1150 "Severe Accident Risks: An Assessment for Five U.S. Nuclear Power Plants", published December 1990 by the Nuclear Regulatory Commission (NRC) is a follow-up to the WASH-1400 and CRAC-II safety studies that employs the methodology of plant-specific Probabilistic Risk Assessment (PRA). The research team, led by Denwood Ross, Joseph Murphy, and Mark Cunningham, concluded that the current generation of nuclear power plants exceeded NRC safety goals.
Sweden began research into nuclear energy in 1947 with the establishment of the Atomic Energy Company, which originated in the ongoing military research and development at the Defence Institute FOA. In 1954, the country built its first small research heavy water reactor. It was followed by two heavy water reactors: Ågesta, a small heat and power reactor in 1964, and Marviken which was finished but never operated, due to several safety issues. Both were heavy water reactors, motivated by the option to use Swedish uranium without isotope enrichment. The option to use plutonium from power reactors was closed only in 1968 with the signing of the Non-Proliferation Treaty. The switch to light water reactors started a few years earlier with Oskarshamn 1.
Nuclear safety is defined by the International Atomic Energy Agency (IAEA) as "The achievement of proper operating conditions, prevention of accidents or mitigation of accident consequences, resulting in protection of workers, the public and the environment from undue radiation hazards". The IAEA defines nuclear security as "The prevention and detection of and response to, theft, sabotage, unauthorized access, illegal transfer or other malicious acts involving nuclear material, other radioactive substances or their associated facilities".
Nuclear safety in the United States is governed by federal regulations issued by the Nuclear Regulatory Commission (NRC). The NRC regulates all nuclear plants and materials in the United States except for nuclear plants and materials controlled by the U.S. government, as well those powering naval vessels.
The United States Government Accountability Office reported more than 150 incidents from 2001 to 2006 of nuclear plants not performing within acceptable safety guidelines. According to a 2010 survey of energy accidents, there have been at least 56 accidents at nuclear reactors in the United States. The most serious of these was the Three Mile Island accident in 1979. Davis-Besse Nuclear Power Plant has been the source of two of the top five most dangerous nuclear incidents in the United States since 1979. Relatively few accidents have involved fatalities.
The Fukushima Daiichi nuclear disaster was an energy accident at the Fukushima Daiichi Nuclear Power Plant in Ōkuma, Fukushima Prefecture, initiated primarily by the tsunami following the Tōhoku earthquake on 11 March 2011. Immediately after the earthquake, the active reactors automatically shut down their sustained fission reactions. However, the ensuing tsunami disabled the emergency generators that would have provided power to control and operate the pumps necessary to cool the reactors. The insufficient cooling led to three nuclear meltdowns, hydrogen-air explosions, and the release of radioactive material in Units 1, 2 and 3 from 12 to 15 March. Loss of cooling also raised concerns over the recently loaded spent fuel pool of Reactor 4, which increased in temperature on 15 March due to the decay heat from the freshly added spent fuel rods but did not boil down to exposure.
A unit of the United States Nuclear Regulatory Commission authorized under the Atomic Energy Act, the Atomic Safety and Licensing Board Panel consists of administrative law judges who hear complaints similar to ordinary district court except for subject matter jurisdiction which pertains to matters under the Act, specifically, nuclear safety issues pertaining to licensed nuclear power plants. There are in excess of one hundred such plants in the United States, some of which are subject to litigation before the panel.
