Nuclear and radiation accidents and incidents
A nuclear and radiation accident is defined by the International Atomic Energy Agency 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, or a 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 accident in 2011.
The impact of nuclear accidents has been a topic of debate since the first nuclear reactors were constructed in 1954 and has been a key factor in public concern about nuclear facilities. Technical measures to reduce the risk of accidents or to minimize the amount of radioactivity released to the environment have been adopted; however, human error remains, and "there have been many accidents with varying impacts as well near misses and incidents". As of 2014, there have been more than 100 serious nuclear accidents and incidents from the use of nuclear power. Fifty-seven accidents or severe incidents have occurred since the Chernobyl disaster, and about 60% of all nuclear-related accidents/severe incidents have occurred in the USA. Serious nuclear power plant accidents include the Fukushima nuclear accident, the Chernobyl disaster, the Three Mile Island accident, and the SL-1 accident. Nuclear power accidents can involve loss of life and large monetary costs for remediation work.
Nuclear submarine accidents include the K-19, K-11, K-27, K-140, K-429, K-222, and K-431 accidents. Serious radiation incidents/accidents include the Kyshtym disaster, the Windscale fire, the radiotherapy accident in Costa Rica, the radiotherapy accident in Zaragoza, the radiation accident in Morocco, the Goiania accident, the radiation accident in Mexico City, the Samut Prakan radiation accident, and the Mayapuri radiological accident in India.
The IAEA maintains a website reporting recent nuclear accidents.
In 2020, the WHO stated that "Lessons learned from past radiological and nuclear accidents have demonstrated that the mental health and psychosocial consequences can outweigh the direct physical health impacts of radiation exposure.""
Nuclear plant accidents
The world's first nuclear reactor meltdown was the NRX reactor at Chalk River Laboratories, Ontario, Canada in 1952.The worst nuclear accident to date is the Chernobyl disaster which occurred in 1986 in the Ukrainian SSR, now Ukraine. The accident killed approximately 30 people directly and damaged approximately $7 billion of property. A study published in 2005 by the World Health Organization estimates that there may eventually be up to 4,000 additional cancer deaths related to the accident among those exposed to significant radiation levels. Radioactive fallout from the accident was concentrated in areas of Belarus, Ukraine and Russia. Other studies have estimated as many as over a million eventual cancer deaths from Chernobyl. Estimates of eventual deaths from cancer are highly contested. Industry, UN and DOE agencies claim low numbers of legally provable cancer deaths will be traceable to the disaster. The UN, DOE and industry agencies all use the limits of the epidemiological resolvable deaths as the cutoff below which they cannot be legally proven to come from the disaster. Independent studies statistically calculate fatal cancers from dose and population, even though the number of additional cancers will be below the epidemiological threshold of measurement of around 1%. These are two very different concepts and lead to the huge variations in estimates. Both are reasonable projections with different meanings. Approximately 350,000 people were forcibly resettled away from these areas soon after the accident. 6,000 people were involved in cleaning Chernobyl and were contaminated.
Social scientist and energy policy expert, Benjamin K. Sovacool has reported that worldwide there have been 99 accidents at nuclear power plants from 1952 to 2009, totaling US$20.5 billion in property damages. There have been comparatively few fatalities associated with nuclear power plant accidents. An academic review of many reactor accident and the phenomena of these events was published by Mark Foreman.
List of nuclear plant accidents and incidents
| Date | Location of accident | Description of accident or incident | Numbers of deaths | Cost | INES level |
| Mayak, Kyshtym, Soviet Union | The Kyshtym disaster was a radiation contamination accident at Mayak, a nuclear fuel reprocessing plant in the Soviet Union. | Estimated 200 possible cancer fatalities | 6 | ||
| Sellafield, Cumberland, United Kingdom | Windscale fire at the British atomic bomb project damaged the core and released an estimated 740 terabecquerels of iodine-131 into the environment. A rudimentary smoke filter constructed over the main outlet chimney successfully prevented a far worse radiation leak. | 0 direct, estimated up to 240 possible cancer victims | 5 | ||
| Idaho Falls, Idaho, United States | Explosion at U.S. Army SL-1 prototype at the National Reactor Testing Station. All 3 operators were killed when a control rod was manually lifted too high. The reactor went from complete shutdown to 20 GW in a few milliseconds. It also jumped over in the air. | 3 | 22 | 4 | |
| Frenchtown Charter Township, Michigan, United States | Meltdown of some fuel elements in the Fermi 1 Reactor at the Enrico Fermi Nuclear Generating Station. Little radiation leakage into the environment. | 0 | 132 | 4 | |
| Lucens reactor, Vaud, Switzerland | On January 21, 1969, it suffered a loss-of-coolant accident, leading to meltdown of one fuel element and radioactive contamination of the cavern, which was then sealed. | 0 | 4 | ||
| Greifswald, East Germany | Electrical error in Greifswald Nuclear Power Plant caused a fire in the main trough that destroyed control lines and five main coolant pumps. | 0 | 443 | 3 | |
| Jaslovské Bohunice, Czechoslovakia | Malfunction during fuel replacement. Fuel rod ejected from reactor into the reactor hall by coolant. | 2 | 1,700 | 4 | |
| Three Mile Island, Pennsylvania, United States | Loss of coolant and partial core meltdown due to operator errors and technical flaws. There was a small release of radioactive gases. See also Three Mile Island accident health effects. | 0 | 2,400 | 5 | |
| Saint-Laurent-Nouan, Loir-et-Cher, France | Partial Core damage after a Power excursion at Saint-Laurent Nuclear Power Plant A2 | 0 | 4 | ||
| Athens, Alabama, United States | Safety violations, operator error and design problems forced a six-year outage at Browns Ferry Unit 2. | 0 | 110 | ||
| Athens, Alabama, United States | Instrumentation systems malfunction during startup, which led to suspension of operations at all three Browns Ferry Units. | 0 | 1,830 | ||
| Plymouth, Massachusetts, United States | Recurring equipment problems forced emergency shutdown of Boston Edison's Pilgrim Nuclear Power Plant. | 0 | 1,001 | ||
| Chernobyl, Chernobyl Raion, Kiev Oblast, Ukrainian SSR, Soviet Union | A flawed reactor design and inadequate safety procedures led to a power surge that damaged the fuel rods of reactor no. 4 of the Chernobyl power plant. This caused an explosion and meltdown, necessitating the evacuation of 300,000 people and dispersing radioactive material across Europe. Around 5% of the core was released into the atmosphere and downwind. | 28 direct, 19 not entirely related and 15 children due to thyroid cancer, as of 2008. Estimated up to 4,000 possible cancer deaths. | 6,700 | 7 | |
| Hamm-Uentrop, West Germany | Experimental THTR-300 reactor released small amounts of fission products to surrounding area. | 0 | 267 | ||
| Surry, Virginia, United States | Feedwater pipe break at Surry Nuclear Power Plant killed 4 workers. | 4 | |||
| Delta, Pennsylvania, United States | Peach Bottom units 2 and 3 shutdown due to cooling malfunctions and unexplained equipment problems. | 0 | 400 | ||
| Lycoming, New York, United States | Malfunctions forced Niagara Mohawk Power Corporation to shut down Nine Mile Point Unit 1. | 0 | 150 | ||
| Lusby, Maryland, United States | Inspections at Calvert Cliff Units 1 and 2 revealed cracks at pressurized heater sleeves, forcing extended shutdowns. | 0 | 120 | ||
| Vandellòs, Spain | A fire damaged the cooling system in unit 1 of the Vandellòs Nuclear Power Plant, getting the core close to meltdown. The cooling system was restored before the meltdown but the unit had to be shut down due to the elevated cost of the repair. | 0 | 220 | 3 | |
| Sosnovy Bor, Leningrad Oblast, Russia | An accident at the Sosnovy Bor nuclear plant leaked radioactive iodine into the air through a ruptured fuel channel. | ||||
| Waterford, Connecticut, United States | Leaking valve forced shutdown of Millstone Nuclear Power Plant Units 1 and 2, multiple equipment failures found. | 0 | 254 | ||
| Crystal River, Florida, United States | Balance-of-plant equipment malfunction forced shutdown and extensive repairs at Crystal River Unit 3. | 0 | 384 | ||
| Gironde, France | Flooding of the power plant caused multiple safety system failures at the Blayais Nuclear Power Plant | 0 | 2 | ||
| Ibaraki Prefecture, Japan | Tokaimura nuclear accident killed two workers, and exposed one more to radiation levels above permissible limits. | 2 | 54 | 4 | |
| Oak Harbor, Ohio, United States | Severe corrosion of reactor vessel head forced 24-month outage of Davis-Besse reactor. | 0 | 143 | 3 | |
| Paks, Hungary | Collapse of fuel rods at Paks Nuclear Power Plant unit 2 during its corrosion cleaning led to leakage of radioactive gases. It remained inactive for 18 months. | 0 | 3 | ||
| Fukui Prefecture, Japan | Steam explosion at Mihama Nuclear Power Plant killed 4 workers and injured 7 more. | 4 | 9 | 1 | |
| Forsmark, Sweden | An electrical fault at Forsmark Nuclear Power Plant caused multiple failures in safety systems critical for reactor cooling. | 0 | 100 | 2 | |
| Fukushima, Japan | The Fukushima nuclear disaster was triggered by a tsunami that flooded and damaged the 3 active reactors at the Fukushima Daiichi nuclear power plant, drowning two workers. Loss of backup electrical power led to overheating, meltdowns, and evacuations. One man died suddenly while carrying equipment during the clean-up. The plant's reactors Nos. 4, 5 and 6 were inactive at the time. | 1 and 3+ labour accidents; plus a broader number of primarily ill or elderly people from evacuation stress | 1,255–2,078 | 7 | |
| Marcoule, France | One person was killed and four injured, one seriously, in a blast at the Marcoule Nuclear Site. The explosion took place in a furnace used to melt metallic waste. | 1 |