With three reactors having at least partial meltdowns at the Fukushima Daiichi power plant in Japan, the country raised the alert level from four to five on a seven-point international scale for atomic incidents Friday.
The International Atomic Energy Agency uses the International Nuclear and Radiological Event Scale to assess the damage done by nuclear accidents. Learn more about the event scale below, and read about some of the worst nuclear disasters in history:
The INES scale, image by the International Atomic Energy Agency
Level 7 Major Accident: A major release of radioactive material with widespread health and environmental effects requiring implementation of planned and extended countermeasures.
1986 — Chernobyl, Ukraine
A nuclear reactor located at a power plant in Chernobyl experienced a steam explosion and fire that caused a meltdown, releasing massive quantities of radioactive material. A significant fraction of the reactor core inventory was released, and contaminated areas of Belarus, Ukraine and the Russian Federation. There were widespread health and environmental effects.
Nuclear Energy Agency reports there were 31 fatalities immediately following the incident, with latent deaths estimated at between 9,000 and 33,000 over the 70 years after, based on current radiation dose risks.
More than five million people received low whole-body doses of radiation, about 1,000 emergency workers received the highest doses of radiation, some of them fatal. By 2002, more than 4,000 thyroid cancer cases were diagnosed among people who were children at the time and ingested radioactive iodine, often through contaminated milk.
Serious Accident: A significant release of radioactive material likely to require implementation of planned countermeasures.
1957 — Kyshtym, Soviet Union
An explosion at a Soviet nuclear weapons plant in Kyshtym resulted in the release of “significant” radioactive material to the environment. The incident forced the evacuation of over 10,000 people from the area contaminated by the blast.
Accident with Wider Consequences: A limited release of radioactive material likely to require implementation of some planned countermeasures and several deaths from radiation.
Four people died and six received some doses of radiation from an abandoned highly radioactive medical teletherapy source that ruptured.
1979–Three Mile Island, Pennsylvania
A cooling malfunction caused part of the core to melt in a reactor, resulting in a limited off-site release of radioactivity over a multi-state area. Doses off-site were less than normal background radiation.
The Nuclear Regulatory Commission determined the accident “led to no deaths or injuries to plant workers or members of the nearby community.”
1957–Windscale Pile, Great Britain
A fire in a reactor core resulted in a limited off-site release of radioactivity. Radioactive dust was detected in Belgium, Germany and Norway. It caused an estimated 200 cases of cancer in Britain.
1952– Chalk River, Canada
The first-ever accident at a nuclear reactor. A reactor shutoff rod failure, combined with several worker errors, led to a major power excursion of more than double the reactor’s rated output. Former President Jimmy Carter, then a U.S. Navy officer based in Schenectady, New York, was among those dispatched by the U.S. to help in the emergency response.
Accident with Local Consequences: A minor release of radioactive material unlikely to result in implementation of planned countermeasures other than local food controls.
2006 — Fleurus, Belgium
Severe health effects for a worker at a commercial irradiation facility as a result of high doses of radiation.
1999 — Tokaimura, Japan
An accident at a uranium processing plant in Tokaimura exposed 55 workers to radiation; one died.
1993 –Tomsk, Russia
Pressure buildup led to an explosive mechanical failure. No deaths were reported after the explosion, and no one was evacuated from the contaminated region.
1980 — Saint Laurent des Eaux, France
A fuel rupture resulted in a minor off-site release of radioactivity.
1977– JaslovskÃ© Bohunice, Slovak Republic
Damaged fuel integrity, extensive corrosion damage of fuel cladding and release of radioactivity.
Information sources include: EPA, IAEA
See also: Lists of nuclear disasters and radioactive incidents
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, 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 radioactivity are released, such as in the Chernobyl disaster in 1986.
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 have occurred since the Chernobyl disaster, and about 60% of all nuclear-related accidents have occurred in the USA. Serious nuclear power plant accidents include the Fukushima Daiichi nuclear disaster (2011), Chernobyl disaster (1986), Three Mile Island accident (1979), and the SL-1 accident (1961). Nuclear power accidents can involve loss of life and large monetary costs for remediation work.
Nuclear-powered submarine core meltdown and other mishaps include the K-19 (1961), K-11 (1965), K-27 (1968), K-140 (1968), K-429 (1970), K-222 (1980), and K-431 (1985). Serious radiation accidents include the Kyshtym disaster, Windscale fire, radiotherapy accident in Costa Rica,radiotherapy accident in Zaragoza,radiation accident in Morocco,Goiania accident,radiation accident in Mexico City, radiotherapy unit accident in Thailand, and the Mayapuri radiological accident in India.
The IAEA maintains a website reporting recent accidents.
Nuclear power plant accidents
See also: Nuclear reactor accidents in the United States, List of nuclear power accidents by country, and List of nuclear and radiation fatalities by country
One of the worst nuclear accidents to date was the Chernobyl disaster which occurred in 1986 in Ukraine. The accident killed 31 people directly and damaged approximately $7 billion of property. A study published in 2005 estimates that there will 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.
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 (defined as incidents that either resulted in the loss of human life or more than US$50,000 of property damage, the amount the US federal government uses to define major energy accidents that must be reported), totaling US$20.5 billion in property damages. Fifty-seven accidents have occurred since the Chernobyl disaster, and almost two-thirds (56 out of 99) of all nuclear-related accidents have occurred in the US. There have been comparatively few fatalities associated with nuclear power plant accidents.
|Date||Location of accident||Description of accident or incident||Dead||Cost|
|000000001957-09-29-0000September 29, 1957||Mayak, Kyshtym, Russia||The Kyshtym disaster was a radiation contamination incident that occurred at Mayak, a Nuclear fuel reprocessing plant in the Soviet Union.||6|
|000000001957-07-26-0000July 26, 1957||Simi Valley, California, United States||Partial core meltdown at Santa Susana Field Laboratory’s Sodium Reactor Experiment.||0||32|
|000000001957-10-10-0000October 10, 1957||Sellafield aka Windscale fire, Cumberland, United Kingdom||A fire at the British atomic bomb project destroyed 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 and ensured minimal damage.||0||5|
|000000001961-01-03-0000January 3, 1961||Idaho Falls, Idaho, United States||Explosion at SL-1 prototype at the National Reactor Testing Station. All 3 operators were killed when a control rod was removed too far.||3||22||4|
|000000001966-10-05-0000October 5, 1966||Frenchtown Charter Township, Michigan, United States||Partial core meltdown of the Fermi 1 Reactor at the Enrico Fermi Nuclear Generating Station. No radiation leakage into the environment.||0||132|
|000000001969-01-21-0000January 21, 1969||Lucens reactor, Vaud, Switzerland||On January 21, 1969, it suffered a loss-of-coolant accident, leading to a partial core meltdown and massive radioactive contamination of the cavern, which was then sealed.||0||5|
|000000001975-01-01-00001975||Sosnovyi Bor, Leningrad Oblast, Russia||There was reportedly a partial nuclear meltdown in Leningrad nuclear power plant reactor unit 1.|
|000000001975-12-07-0000December 7, 1975||Greifswald, East Germany||Electrical error causes fire in the main trough that destroys control lines and five main coolant pumps||0||443||3|
|000000001976-01-05-0000January 5, 1976||Jaslovské Bohunice, Czechoslovakia||Malfunction during fuel replacement. Fuel rod ejected from reactor into the reactor hall by coolant (CO2).||2||4|
|000000001977-02-22-0000February 22, 1977||Jaslovské Bohunice, Czechoslovakia||Severe corrosion of reactor and release of radioactivity into the plant area, necessitating total decommission||0||1,700||4|
|000000001979-03-28-0000March 28, 1979||Three Mile Island, Pennsylvania, United States||Loss of coolant and partial core meltdown due to operator errors. There is a small release of radioactive gases. See also Three Mile Island accident health effects.||0||2,400||5|
|000000001984-09-15-0000September 15, 1984||Athens, Alabama, United States||Safety violations, operator error, and design problems force a six-year outage at Browns Ferry Unit 2.||0||110|
|000000001985-03-09-0000March 9, 1985||Athens, Alabama, United States||Instrumentation systems malfunction during startup, which led to suspension of operations at all three Browns Ferry Units||0||1,830|
|000000001986-04-11-0000April 11, 1986||Plymouth, Massachusetts, United States||Recurring equipment problems force emergency shutdown of Boston Edison’s Pilgrim Nuclear Power Plant||0||1,001|
|000000001986-04-26-0000April 26, 1986||Chernobyl, Chernobyl Raion (Now Ivankiv Raion), Kiev Oblast, Ukraininan SSR, Soviet Union||Overheating, steam explosion, fire, and meltdown, necessitating the evacuation of 300,000 people from Chernobyl and dispersing radioactive material across Europe (see Effects of the Chernobyl disaster)||30 direct, 19 not entirely related and 15 minors due to thyroid cancer, as of 2008.||6,700||7|
|000000001986-05-04-0000May 4, 1986||Hamm-Uentrop, West Germany||Experimental THTR-300 reactor releases small amounts of fission products (0.1 GBq Co-60, Cs-137, Pa-233) to surrounding area||0||267|
|000000001987-03-31-0000March 31, 1987||Delta, Pennsylvania, United States||Peach Bottom units 2 and 3 shutdown due to cooling malfunctions and unexplained equipment problems||0||400|
|000000001987-12-19-0000December 19, 1987||Lycoming, New York, United States||Malfunctions force Niagara Mohawk Power Corporation to shut down Nine Mile Point Unit 1||0||150|
|000000001989-03-17-0000March 17, 1989||Lusby, Maryland, United States||Inspections at Calvert Cliff Units 1 and 2 reveal cracks at pressurized heater sleeves, forcing extended shutdowns||0||120|
|000000001992-03-01-0000March 1992||Sosnovyi Bor, Leningrad Oblast, Russia||An accident at the Sosnovy Bor nuclear plant leaked radioactive gases and iodine into the air through a ruptured fuel channel.|
|000000001996-02-20-0000February 20, 1996||Waterford, Connecticut, United States||Leaking valve forces shutdown Millstone Nuclear Power Plant Units 1 and 2, multiple equipment failures found||0||254|
|000000001996-09-02-0000September 2, 1996||Crystal River, Florida, United States||Balance-of-plant equipment malfunction forces shutdown and extensive repairs at Crystal River Unit 3||0||384|
|000000001999-09-30-0000September 30, 1999||Ibaraki Prefecture, Japan||Tokaimura nuclear accident killed two workers, and exposed one more to radiation levels above permissible limits.||2||54||4|
|000000002002-02-16-0000February 16, 2002||Oak Harbor, Ohio, United States||Severe corrosion of control rod forces 24-month outage of Davis-Besse reactor||0||143||3|
|000000002004-08-09-0000August 9, 2004||Fukui Prefecture, Japan||Steam explosion at Mihama Nuclear Power Plant kills 4 workers and injures 7 more||4||9||1|
|000000002006-07-25-0000July 25, 2006||Forsmark, Sweden||An electrical fault at Forsmark Nuclear Power Plant caused one reactor to be shut down||0||100||2|
|000000002011-03-11-0000March 11, 2011||Fukushima, Japan||A tsunami flooded and damaged the plant's 5 active reactors, 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 6th reactor was inactive at the time.||2+||7|
|12 September 2011||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|
Nuclear reactor attacks
Main article: Vulnerability of nuclear plants to attack
See also: Nuclear terrorism
The vulnerability of nuclear plants to deliberate attack is of concern in the area of nuclear safety and security.Nuclear power plants, civilian research reactors, certain naval fuel facilities, uranium enrichment plants, fuel fabrication plants, and even potentially uranium mines are vulnerable to attacks which could lead to widespread radioactive contamination. The attack threat is of several general types: commando-like ground-based attacks on equipment which if disabled could lead to a reactor core meltdown or widespread dispersal of radioactivity; and external attacks such as an aircraft crash into a reactor complex, or cyber attacks.
The United States 9/11 Commission found that nuclear power plants were potential targets originally considered for the September 11, 2001 attacks. If terrorist groups could sufficiently damage safety systems to cause a core meltdown at a nuclear power plant, and/or sufficiently damage spent fuel pools, such an attack could lead to widespread radioactive contamination. The Federation of American Scientists have said that if nuclear power use is to expand significantly, nuclear facilities will have to be made extremely safe from attacks that could release massive quantities of radioactivity into the community. New reactor designs have features of passive nuclear safety, which may help. In the United States, the NRC carries out "Force on Force" (FOF) exercises at all Nuclear Power Plant (NPP) sites at least once every three years.
Nuclear reactors become preferred targets during military conflict and, over the past three decades, have been repeatedly attacked during military air strikes, occupations, invasions and campaigns. Various acts of civil disobedience since 1980 by the peace group Plowshares have shown how nuclear weapons facilities can be penetrated, and the group's actions represent extraordinary breaches of security at nuclear weapons plants in the United States. The National Nuclear Security Administration has acknowledged the seriousness of the 2012 Plowshares action. Non-proliferation policy experts have questioned "the use of private contractors to provide security at facilities that manufacture and store the government's most dangerous military material".Nuclear weapons materials on the black market are a global concern, and there is concern about the possible detonation of a small, crude nuclear weapon or dirty bomb by a militant group in a major city, causing significant loss of life and property.
The number and sophistication of cyber attacks is on the rise. Stuxnet is a computer worm discovered in June 2010 that is believed to have been created by the United States and Israel to attack Iran's nuclear facilities. It switched off safety devices, causing centrifuges to spin out of control. The computers of South Korea's nuclear plant operator (KHNP) were hacked in December 2014. The cyber attacks involved thousands of phishing emails containing malicious codes, and information was stolen.
Radiation and other accidents and incidents
See also: List of civilian radiation accidents and List of nuclear weapons tests of the United States
Serious radiation and other accidents and incidents include:
- May 1945: Albert Stevens was one of several subjects of a human radiation experiment, and was injected with plutonium without his knowledge or informed consent. Although Stevens was the person who received the highest dose of radiation during the plutonium experiments, he was neither the first nor the last subject to be studied. Eighteen people aged 4 to 69 were injected with plutonium. Subjects who were chosen for the experiment had been diagnosed with a terminal disease. They lived from 6 days up to 44 years past the time of their injection. Eight of the 18 died within two years of the injection. All died from their preexisting terminal illness, or cardiac illnesses. None died from the plutonium itself. Patients from Rochester, Chicago, and Oak Ridge were also injected with plutonium in the Manhattan Project human experiments.
- 6–9 August 1945: On the orders of President Harry S. Truman, a uranium-gun design bomb, Little Boy, was used against the city of Hiroshima, Japan. Fat Man, a plutonium implosion-design bomb was used against the city of Nagasaki. The two weapons killed approximately 120,000 to 140,000 civilians and military personnel instantly and thousands more have died over the years from radiation sickness and related cancers.
- August 1945: Criticality accident at US Los Alamos National Laboratory. Harry Daghlian dies.
- May 1946: Criticality accident at Los Alamos National Laboratory. Louis Slotin dies.
- February 13, 1950: a Convair B-36B crashed in northern British Columbia after jettisoning a Mark IVatomic bomb. This was the first such nuclear weapon loss in history.
- December 12, 1952: NRX AECL Chalk River Laboratories, Chalk River, Ontario, Canada. Partial meltdown, about 10,000 Curies released. Approximately 1202 people were involved in the two year cleanup. Future president Jimmy Carter was one of the many people that helped clean up the accident.
- 15/03/1953 – Mayak, Former Soviet Union. Criticality accident. Contamination of plant personnel occurred.
- 1954: The 15 Mt Castle Bravo shot of 1954 which spread considerable nuclear fallout on many Pacific islands, including several which were inhabited, and some that had not been evacuated.
- March 1, 1954: Daigo Fukuryū Maru, 1 fatality.
- September 1957: a plutonium fire occurred at the Rocky Flats Plant, which resulted in the contamination of Building 71 and the release of plutonium into the atmosphere, causing US $818,600 in damage.
- 21/04/1957 - Mayak, Former Soviet Union. Criticality accident in the factory number 20 in the collection oxalate decantate after filtering sediment oxalate enriched uranium. Six people received doses of 300 to 1,000 rem (four women and two men), one woman died.
- September 1957: Kyshtym disaster: Nuclear waste storage tank explosion at Chelyabinsk, Russia. 200+ fatalities, believed to be a conservative estimate; 270,000 people were exposed to dangerous radiation levels. Over thirty small communities were removed from Soviet maps between 1958 and 1991. (INES level 6)
- October 1957: Windscale fire, UK. Fire ignites a "plutonium pile" (an air cooled, graphite moderated, uranium fuelled reactor that was used for plutonium and isotope production) and contaminates surrounding dairy farms. An estimated 33 cancer deaths.
- 1957-1964: Rocketdyne located at the Santa Susanna Field Lab, 30 miles north of Los Angeles, California operated ten experimental nuclear reactors. Numerous accidents occurred including a core meltdown. Experimental reactors of that era were not required to have the same type of containment structures that shield modern nuclear reactors. During the Cold War time in which the accidents that occurred at Rocketdyne, these events were not publicly reported by the Department of Energy.
- 1958: Fuel rupture and fire at the National Research Universal reactor (NRU), Chalk River, Canada.
- 10/02/1958 - Mayak, Former Soviet Union. Criticality accident in SCR plant. Conducted experiments to determine the critical mass of enriched uranium in a cylindrical container with different concentrations of uranium in solution. Staff broke the rules and instructions for working with YADM (nuclear fissile material). When SCR personnel received doses from 7600 to 13,000 rem. Three people died, one man got radiation sickness and went blind.
- December 30, 1958: Cecil Kelley criticality accident at Los Alamos National Laboratory.
- March 1959: Santa Susana Field Laboratory, Los Angeles, California. Fire in a fuel processing facility.
- July 1959: Santa Susana Field Laboratory, Los Angeles, California. Partial meltdown.
- 7 June 1960: the 1960 Fort Dix IM-99 accident destroyed a CIM-10 Bomarc nuclear missile and shelter and contaminated the BOMARC Missile Accident Site in New Jersey.
- 24 January 1961: the 1961 Goldsboro B-52 crash occurred near Goldsboro, North Carolina. A B-52 Stratofortress carrying two Mark 39 nuclear bombs broke up in mid-air, dropping its nuclear payload in the process.
- July 1961: soviet submarine K-19 accident. Eight fatalities and more than 30 people were over-exposed to radiation.
- March, 21 -August 1962: radiation accident in Mexico City, four fatalities.
- May 1962: The Cuban Missile Crisis was a 13-day confrontation in October 1962 between the Soviet Union and Cuba on one side and the United States on the other side. The crisis is generally regarded as the moment in which the Cold War came closest to turning into a nuclear conflict and is also the first documented instance of mutual assured destruction (MAD) being discussed as a determining factor in a major international arms agreement.
- 23 July 1964: Wood River Junction criticality accident. Resulted in 1 fatality
- 1964, 1969: Santa Susana Field Laboratory, Los Angeles, California. Partial meltdowns.
- 1965 Philippine Sea A-4 crash, where a Skyhawk attack aircraft with a nuclear weapon fell into the sea. The pilot, the aircraft, and the B43 nuclear bomb were never recovered. It was not until the 1980s that the Pentagon revealed the loss of the one-megaton bomb.
- October 1965: US CIA-led expedition abandons a nuclear-powered telemetry relay listening device on Nanda Devi
- January 17, 1966: the 1966 Palomares B-52 crash occurred when a B-52G bomber of the USAF collided with a KC-135 tanker during mid-air refuelling off the coast of Spain. The KC-135 was completely destroyed when its fuel load ignited, killing all four crew members. The B-52G broke apart, killing three of the seven crew members aboard. Of the four Mk28 type hydrogen bombs the B-52G carried, three were found on land near Almería, Spain. The non-nuclear explosives in two of the weapons detonated upon impact with the ground, resulting in the contamination of a 2-square-kilometer (490-acre) (0.78 square mile) area by radioactiveplutonium. The fourth, which fell into the Mediterranean Sea, was recovered intact after a 2½-month-long search.
- January 21, 1968: the 1968 Thule Air Base B-52 crash involved a United States Air Force (USAF) B-52 bomber. The aircraft was carrying four hydrogen bombs when a cabin fire forced the crew to abandon the aircraft. Six crew members ejected safely, but one who did not have an ejection seat was killed while trying to bail out. The bomber crashed onto sea ice in Greenland, causing the nuclear payload to rupture and disperse, which resulted in widespread radioactive contamination.
- May 1968: Soviet submarine K-27 reactor near meltdown. 9 people died, 83 people were injured. In August 1968, the Project 667 A - Yankee class nuclear submarine K-140 was in the naval yard at Severodvinsk for repairs. On August 27, an uncontrolled increase of the reactor's power occurred following work to upgrade the vessel. One of the reactors started up automatically when the control rods were raised to a higher position. Power increased to 18 times its normal amount, while pressure and temperature levels in the reactor increased to four times the normal amount. The automatic start-up of the reactor was caused by the incorrect installation of the control rod electrical cables and by operator error. Radiation levels aboard the vessel deteriorated.
- 10/12/1968 - Mayak, Former Soviet Union. Criticality accident. Plutonium solution was poured into a cylindrical container with dangerous geometry. One person died, another took a high dose of radiation and radiation sickness, after which he had two legs and his right arm amputated.
- January 1969: Lucens reactor in Switzerland undergoes partial core meltdown leading to massive radioactive contamination of a cavern.
- 1974–1976: Columbus radiotherapy accident, 10 fatalities, 88 injuries from cobalt-60 source.
- July 1978: Anatoli Bugorski was working on U-70, the largest Sovietparticle accelerator, when he accidentally exposed his head directly to the proton beam. He survived, despite suffering some long-term damage.
- July 1979: Church Rock Uranium Mill Spill in New Mexico, USA, when United Nuclear Corporation's uranium mill tailings disposal pond breached its dam. Over 1,000 tons of radioactive mill waste and millions of gallons of mine effluent flowed into the Puerco River, and contaminants traveled downstream.
- 1980 to 1989: The Kramatorsk radiological accident happened in Kramatorsk, Ukrainian SSR. In 1989, a small capsule containing highly radioactive caesium-137 was found inside the concrete wall of an apartment building. 6 residents of the building died from leukemia and 17 more received varying radiation doses. The accident was detected only after the residents called in a health physicist.
- 1980: Houston radiotherapy accident, 7 fatalities.
- October 5, 1982: Lost radiation source, Baku, Azerbaijan, USSR. 5 fatalities, 13 injuries.
- March 1984: Radiation accident in Morocco, eight fatalities from overexposure to radiation from a lost iridium-192 source.
- 1984: Fernald Feed Materials Production Center gained notoriety when it was learned that the plant was releasing millions of pounds of uranium dust into the atmosphere, causing major radioactive contamination of the surrounding areas. That same year, employee Dave Bocks, a 39-year-old pipefitter, disappeared during the facility's graveyard shift and was later reported missing. Eventually, his remains were discovered inside a uranium processing furnace located in Plant 6.
- August 1985: Soviet submarine K-431 accident. Ten fatalities and 49 other people suffered radiation injuries.
- January 4, 1986: an overloaded tank at Sequoyah Fuels Corporation ruptured and released 14.5 tons of uranium hexafluoride gas (UF6), causing the death of a worker, the hospitalization of 37 other workers, and approximately 100 downwinders.
- October 1986: Soviet submarine K-219 reactor almost had a meltdown. Sergei Preminin died after he manually lowered the control rods, and stopped the explosion. The submarine sank three days later.
- September 1987: Goiania accident. Four fatalities, and following radiological screening of more than 100,000 people, it was ascertained that 249 people received serious radiation contamination from exposure to caesium-137. In the cleanup operation, topsoil had to be removed from several sites, and several houses were demolished. All the objects from within those houses were removed and examined. Time magazine has identified the accident as one of the world's "worst nuclear disasters" and the International Atomic Energy Agency called it "one of the world's worst radiological incidents".
- 1989: San Salvador, El Salvador; one fatality due to violation of safety rules at cobalt-60 irradiation facility.
- 1990: Soreq, Israel; one fatality due to violation of safety rules at cobalt-60 irradiation facility.
- December 16 - 1990: radiotherapy accident in Zaragoza. Eleven fatalities and 27 other patients were injured.
- 1991: Neswizh, Belarus; one fatality due to violation of safety rules at cobalt-60 irradiation facility.
- 1992: Jilin, China; three fatalities at cobalt-60 irradiation facility.
- 1992: USA; one fatality.
- April 1993: accident at the Tomsk-7 Reprocessing Complex, when a tank exploded while being cleaned with nitricacid. The explosion released a cloud of radioactive gas. (INES level 4).
- 1994: Tammiku, Estonia; one fatality from disposed caesium-137 source.
- August — December 1996: Radiotherapy accident in Costa Rica. Thirteen fatalities and 114 other patients received an overdose of radiation.
- 1996: an accident at Pelindaba research facility in South Africa results in the exposure of workers to radiation. Harold Daniels and several others die from cancers and radiation burns related to the exposure.
- June 1997: Sarov, Russia; one fatality due to violation of safety rules.
- May 1998: The Acerinox accident was an incident of radioactive contamination in Southern Spain. A caesium-137 source managed to pass through the monitoring equipment in an Acerinoxscrap metal reprocessing plant. When melted, the caesium-137 caused the release of a radioactive cloud.
- September 1999: two fatalities at criticality accident at Tokaimura nuclear accident (Japan)
- March 2011: Fukushima I nuclear accidents, Japan and the radioactive discharge at the Fukushima Daiichi Power Station.
- January 17, 2014: At the Rössing Uranium Mine, Namibia, a catastrophic structural failure of a leach tank resulted in a major spill. The France-based laboratory, CRIIRAD, reported elevated levels of radioactive materials in the area surrounding the mine. Workers were not informed of the dangers of working with radioactive materials and the health effects thereof.
- February 1, 2014: Designed to last ten thousand years, the Waste Isolation Pilot Plant (WIPP) site approximately 26 miles (42 km) east of Carlsbad, New Mexico, United States, had its first leak of airborne radioactive materials. 140 employees working underground at the time were sheltered indoors. Thirteen of these tested positive for internal radioactive contamination increasing their risk for future cancers or health issues. A second leak at the plant occurred shortly after the first, releasing plutonium and other radiotoxins causing concern to nearby communities.
Worldwide nuclear testing summary
Between 16 July 1945 and 23 September 1992, the United States maintained a program of vigorous nuclear testing, with the exception of a moratorium between November 1958 and September 1961. By official count, a total of 1,054 nuclear tests and two nuclear attacks were conducted, with over 100 of them taking place at sites in the Pacific Ocean, over 900 of them at the NevadaTest Site, and ten on miscellaneous sites in the United States (Alaska, Colorado, Mississippi, and New Mexico). Until November 1962, the vast majority of the U.S. tests were atmospheric (that is, above-ground); after the acceptance of the Partial Test Ban Treaty all testing was regulated underground, in order to prevent the dispersion of nuclear fallout.
The U.S. program of atmospheric nuclear testing exposed a number of the population to the hazards of fallout. Estimating exact numbers, and the exact consequences, of people exposed has been medically very difficult, with the exception of the high exposures of Marshall Islanders and Japanese fishers in the case of the Castle Bravo incident in 1954. A number of groups of U.S. citizens — especially farmers and inhabitants of cities downwind of the Nevada Test Site and U.S. military workers at various tests — have sued for compensation and recognition of their exposure, many successfully. The passage of the Radiation Exposure Compensation Act of 1990 allowed for a systematic filing of compensation claims in relation to testing as well as those employed at nuclear weapons facilities. As of June 2009 over $1.4 billion total has been given in compensation, with over $660 million going to "downwinders".
Trafficking and thefts
See also: Vulnerability of nuclear plants to attack
The International Atomic Energy Agency says there is "a persistent problem with the illicit trafficking in nuclear and other radioactive materials, thefts, losses and other unauthorized activities". The IAEA Illicit Nuclear Trafficking Database notes 1,266 incidents reported by 99 countries over the last 12 years, including 18 incidents involving HEU or plutonium trafficking:
- Security specialist Shaun Gregory argued in an article that terrorists have attacked Pakistani nuclear facilities three times in the recent past; twice in 2007 and once in 2008.
- In November 2007, burglars with unknown intentions infiltrated the Pelindaba nuclear research facility near Pretoria, South Africa. The burglars escaped without acquiring any of the uranium held at the facility.
- In February 2006, Oleg Khinsagov of Russia was arrested in Georgia, along with three Georgian accomplices, with 79.5 grams of 89 percent enriched HEU.
- The Alexander Litvinenko poisoning with radioactive polonium "represents an ominous landmark: the beginning of an era of nuclear terrorism," according to Andrew J. Patterson.
Main articles: Nuclear meltdown and Design basis accident
A nuclear meltdown is a severe nuclear reactor accident that results in reactor core damage from overheating. It has been defined as the accidental melting of the core of a nuclear reactor, and refers to the core's either complete or partial collapse.