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Nuclear and radiation accidents and incidents

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Notable Nuclear Accidents

1940s

  • May 21, 1946 – Canadian physicist Louis Slotin manually assembles a critical mass of plutonium while demonstrating his technique to visiting scientists at Los Alamos, New Mexico. The device consists of two half-spheres of beryllium-covered plutonium, which can be moved together slowly to measure the criticality. Normally the device would be operated by machinery, but Slotin distrusted the devices and manually operated it by holding the upper sphere with his thumb inserted in a hole in the top like a bowling ball. In most experiments, a number of washers would be arranged to prevent the two hemispheres from falling together completely, but he had removed them. In order to slowly bring the two pieces together, he rested one edge on the lower sphere and rotated a slot screwdriver between the other edge to control the separation. At one point, the screwdriver slipped and the assembly went critical while he was still holding onto it. None of the seven observers received a lethal dose, but Slotin died on the 30th from massive radiation poisoning, with an estimated dose of 1,000 rad. This was dramatized in the movie Fat Man and Little Boy, except that the movie placed the event before the Trinity test[3]—in reality, a device that Slotin had helped to assemble.[4]

1950s

  • 1954 – The submarine USS Seawolf (SSN-575) scuttles an experimental sodium-cooled reactor in 9,000 feet of water off the Delaware/Maryland coast. At 33 kCi it's likely the most radioactive single object ever deliberately sunk, and has not been retrieved as of 2003. The reactor had problems with corrosion from the coolant, and was replaced by a conventional light-water reactor.
  • March 1, 1954 – During the early morning of March 1st, a Japanese Fishing boat, the Fukuryu Maru, or "Lucky Dragon," and its crew witness what they believe to be the sun rising to the west of them as they sail in the Pacific Ocean. In fact, they are witnessing the 12 megaton detonation of the hydrogen bomb "Bravo" at the Bikini Atoll, 85 miles away. Several hours later, white ash begins to fall like snow onto the boat. Many of the crew members gather the ash into bags as souvenirs. Before the evening is out, the entire crew has become ill. The 23 crew members are hospitalized in Japan and one later dies of kidney failure due to radiation exposure. The incident brings a rift in relations between Japan and the United States because the US did not warn Japan or any other country of the bomb's testing, leaving the Lucky Dragon exposed to the fallout. (In partial mitigation, the device yielded about 2½ times what was predicted because of an overlooked reaction; the US expanded its exclusion zones in later tests.) The US issued an apology and paid 2 million US dollars in compensation. Additionally, in a similar incident, another 86 people living on Rongelap Atoll are sickened by the accumulation of an inch or more of radioactive dust.[13]
  • 1957 &ndash Keleket Co.: A capsule of radium salt bursts. This causes a five-month decontamination costing US$250,000. The capsule was used to calibrate the radiation-measuring devices produced there.
  • September 29, 1957 – Cooling system failure results in a nuclear waste storage tank explosion at Mayak, a spent nuclear fuel reprocessing facility near Chelyabinsk, Russia, releasing some 20 MCi and subjecting (by various estimates) 124,000 to 270,000 people to dangerously high levels of radiation.[22] Of these, only 7,500 were evacuated, most of them too late to prevent dangerous levels of exposure. A series of less prominent accidents preceded and followed this meltdown, in addition to a polluted water supply for people remaining in the area. More than 500,000 inhabitants of the region have been exposed to radiation as a result.
  • October 7–11, 1957 – Windscale Pile No. 1 at Sellafield north of Liverpool, England begins a process dubbed "annealing" to release Wigner energy from graphite portions of the reactor. Technicians mistakenly overheat the reactor pile because poorly placed temperature sensors indicate the reactor is cooling rather than heating. A fire results in the following days and is finally extinguished on the 11th, but it is discovered that the air-cooled reactor had spewed radioactive gases throughout the surrounding countryside. Milk distribution is banned in a 200 square mile area around the reactor. Over the following years, Pile No. 1 and neighboring Pile No. 2 are shut down, although nuclear decommission work resumes in 1990 and continues at least through 1999. The incident, classified as the same scale as Three Mile Island, is later blamed for dozens of cancer deaths.[23][24][25][26]
  • January 31, 1958 – A B-47 with a fully-armed nuclear weapon crashes and burns for 7 hours at a US Air Force base, 90 miles N.E. of Rabat, Morocco. The Air Force evacuates everyone within 1 mile of the base. Many vehicles and aircraft are contaminated. However, Moroccan officials are not notified.
  • February 5, 1958 – A damaged B-47 off the coast of the US state of Georgia, flying near Tybee Island, jettisons a weapon lacking its nuclear core from 7200 feet after attempting to land three times at Hunter Air Force Base. The plane had suffered a collision with an F-86 during simulated combat near Savannah, Georgia, and could not land safely with the heavy bomb on board. The bomb is never recovered.
  • 1958 – Soviet military reactor near Chelyabinsk releases radioactive dust. 12 villages evacuated.
  • 1958 – In the NRU reactor in Chalk River, Canada, several metallic uranium fuel rods overheat and rupture inside the core. One of the damaged rods catches fire and is torn in two while it is being removed from the core by a robotic crane. As the remote-controlled crane passes overhead carrying the larger portion of the damaged rod, a three-foot length of burning uranium fuel breaks off and falls into a shallow maintenance pit. The ventilation system is jammed in the "open" position, thereby contaminating the accessible areas of the building as well as a sizable area downwind from the reactor site. A relay team of scientists and technicians eventually extinguishes the fire by running past the pit at top speed while wearing full protective gear, dumping buckets of wet sand on the burning uranium fuel.
  • March 11, 1958 – A B-47 from Hunter Air Force Base in Georgia en route to an overseas base drops an unarmed nuclear weapon into the yard of Walter Gregg and his family in Mars Bluff, near Florence, South Carolina. The trigger explodes and destroys Gregg's house, injuring six members of his family. The blast forms a crater 60 feet wide and 30 feet deep. Five houses and a church are also damaged. Residents carry away radioactive pieces of the bomb for souvenirs, which have to be retrieved by an Air Force cleanup crew. Five months later the Air Force pays the Greggs $54,000 of his estimated $300,000 loss.
  • December 30, 1958 – A critical mass of plutonium solution is accidentally assembled during chemical purification at Los Alamos. The crane operator dies of acute radiation sickness. The March 1961 Journal of Occupational Medicine prints a special supplement medically analyzing this accident. Hand-manipulations of critical assemblies are abandoned as a matter of policy in U.S. federal facilities after this accident.
  • October 1959 – One killed and 3 seriously burned in explosion and fire of prototype reactor for the USS Triton (SSRN/SSN-586) at the United States Navy's training center in West Milton, New York. The Navy stated "The explosion was completely unrelated to the reactor or any of its principal auxiliary systems," but sources familiar with the operation claim that the high-pressure air flask that exploded was to feed a crucial reactor-problem backup system.

1960s

  • 1961 – The USS Theodore Roosevelt (SSBN-600) attempts to dump the depleted resin from its demineralization system (used to remove dissolved radioactive minerals and particles from the primary coolant loops of submarines). The ship is contaminated when wind blows resin back onto the ship.
  • January 3, 1961 – At the National Reactor Testing Station in Idaho Falls, Idaho, the experimental SL-1 reactor has a criticality incident with a steam explosion and a severe dispersal of radioactive material, killing three workers at the installation. The radiation is contained. The portable reactor had manually-actuated control rods. Moving a single rod could cause the criticality incident. The rods were known to jam in the lightweight aluminum housing. Some investigators believe that a rod stuck and then suddenly released, causing the criticality incident. One worker was found pinned to the ceiling by a control rod, apparently driven by the steam.
  • December 10, 1961 – An underground nuclear test explosion unexpectedly releases clouds of radioactive steam, causing several New Mexico highways to be closed.
  • April 10, 1963 – The nuclear submarine USS Thresher (SSN-593) sinks east of Boston, Massachusetts with 129 men onboard during sea trials. A year earlier, just before the end of its refit interval, the boat had been abused in a munitions test where it literally tried to approach explosions as closely as possible. The boat was refitted afterward, and sank on its sea trials. In a show of poor planning, the sea trial was conducted where the bottom was below the hull's crush depth. In the yard, destructive tests of a few silver-soldered pipe connections had failed. At the time, nondestructive testing was unknown, and no test records were available. The investigators believed that the sinking was caused by the failure of a major through-hull silver-soldered connection, such as a secondary-loop cooling inlet, and that the reactor and its design was not responsible. The reactor was not recovered.
  • April 1964 – A US nuclear-powered navigational satellite burns up in the atmosphere, releasing 17 kCi of Plutonium-238.
  • January 17, 1966 – Near Palomares, Spain during over-ocean in-flight refueling, a B-52 collides with a United States Air Force KC-135 jet tanker. Eight of the eleven crew members are killed. The KC-135's 40,000 gallons of jet fuel burn. Two hydrogen bombs rupture, dispersing radioactive particles over nearby farms. An intact bomb lands near Palomares. The fourth bomb was lost at sea 12 miles off the coast. A search involving three months and 12,000 men recover it. During the ensuing cleanup, 1,500 tons of radioactive soil and tomato plants are shipped to a nuclear dump in Aiken, South Carolina. The U.S. settled claims by 522 Palomares residents for $600,000. The town also received a $200,000 desalinization plant.
  • January 22, 1968 – 7 miles south of Thule Air Force Base, Greenland, a fire breaks out in the navigator's compartment of a B-52 which crashes, scattering three hydrogen bombs on land and dropping one into the sea. During a cleanup complicated by Greenland's harsh weather, contaminated ice and airplane debris are buried in the U.S. Bomb fragments were recycled by Pantex, in Amarillo, Texas. Danes were outraged by the event because Greenland is a Danish possesion, and Denmark forbids nuclear weapons on its territory. Denmark had massive demonstrations against the U.S. One warhead was recovered by Navy Seals and Seabees (U.S. naval engineers) in 1979, An August 2000 report suggests that the other bomb remains at the bottom of Baffin Bay.
  • May 21, 1968 – The USS Scorpion (SSN-589), a nuclear-powered attack submarine carrying two Mark 45 ASTOR torpedoes with nuclear warheads, is lost with 99 sailors onboard. The nuclear material has not been recovered. The submarine has been photographed at the ocean bottom, and the U.S. Navy periodically monitors the location for radioactivity. Supposedly there has been no plutonium leakage to date.
  • December 9, 1968 – In Nevada, an underground test of nuclear explosives releases clouds of radioactive steam.
  • January 21, 1969 – A coolant malfunction from an experimental underground nuclear reactor at Lucens Vad, Switzerland, released a large amount of radiation into a cavern, which was then sealed.
  • May 11, 1969 – 5 kg of plutonium burns at Rocky Flats. Hundreds of railway cars are used to transport the contamination to Idaho Falls, where it is left in unlined trenches over one of the US's most significant aquifers

1970s

  • December 18, 1970 – The Baneberry underground test vents 6.7 MCi through a fissure in the rock.[29] Fallout later drifts into Canada, violating the 1963 test-ban treaty.[30]
  • March 1972 – Senator Mike Gravel of Alaska submits information to the Congressional Record indicating that a routine check of a nuclear power plant showed radioactivity in the building's water—including the plant drinking fountain—which had been cross-connected with a 3,000 gallon tank of radioactive water.
  • December 1972 – A major fire and two explosions at a plutonium fabrication plant in Pauling, New York cause plutonium to contaminate the plant and grounds, resulting in its permanent shutdown.
  • 1974 – Workers at the Isomedix Co in New Jersey report that radioactive water was flushed down toilets, contaminating sewer pipes. Also that year in a different incident at the same company, a worker receives a dose of radiation considered lethal, but was saved by prompt hospital treatment.
  • 1975 – The USS Guardfish attempts to dump the depleted resin from its demineralization system (used to remove dissolved radioactive minerals and particles from the primary coolant loops of submarines). The ship is contaminated when the wind blows resin back onto the ship. This type of accident is fairly common (see 1961).
  • March 22, 1975 – A fire at the Brown's Ferry nuclear reactor located in Decatur, Alabama causes a dangerous lowering of coolant water levels.
  • July 16, 1979 (34th anniversary of the Trinity test) – In Church Rock, New Mexico, the earth/clay dike of a uranium mill's "temporary" settling/evaporating pond fails. The pond was past its planned and licensed life and had been filled two feet deeper than design despite evident cracking. The incident drains about 100 million gallons of radioactive liquids and 1100 tons of solid wastes, which settle out up to 70 miles down the Rio Puerco[31]
  • September 29, 1979 – Governor Bruce Babbitt of Arizona orders the National Guard to clean up American Atomics' Tucson plant, which he believes has been leaking. (Reports of problems by the Arizona Atomic Energy Commission had been stalled by a commissioner, who was also a vice-president of American Atomics.) At the kitchen for the public school system across the street from the plant, $300,000 of food is found contaminated by radioactive tritium; chocolate cake had 56 nCi/L, 2½ times the "safe" standard. A nuclear official accuses Babbitt of "greed for publicity."[32][33]

1980s

  • September 19, 1980 – An Air Force repairman doing routine maintenance in a Titan II ICBM silo drops a wrench socket which rolls off a work platform and falls to the bottom of the silo. The socket strikes the missile, causing a leak from a pressurized fuel tank. The missile complex and surrounding area is evacuated and eight and a half hours later, vapors within the silo ignite and explode. The explosion fatally injures an Air Force specialist and twenty-one other USAF personnel are injured.
  • November 2, 1981 – At the US Submarine Pens in Scotland, a fully-armed Poseidon missile is accidentally dropped 17 feet from a crane while being transferred from a submarine to its tender.
  • 1982 – International Nutronics of Dover, New Jersey completely contaminates its plant, forcing its closure. IN used radiation to treat gems for color, modify chemicals, and sterilize food and medical supplies. The incident involved a pump siphoning water from the baths to the floor. The water entered the sewer system of Dover. The Nuclear Regulatory Commission was informed of the accident ten months later by a whistleblower.
  • February 25, 1983 – In Salem, New Jersey, the Salem 1 reactor fails to shut down automatically, but the operator detects the problem 90 seconds before an "incident" can occur. Automatic systems had failed to respond three days earlier. Salem 1 also experienced radioactive gas leaks in March 1981 and September 1982.
  • 1986 – The US Government declassifies 19,000 pages of documents indicating that between 1946 and 1986, the Hanford Engineering Works in Hanford, Washington released billions of gallons of radioactive liquids and billions of cubic meters of gases containing plutonium and other isotopes. Detrimental effects were noted as early as 1948, but reports critical of the facilities remained classified. Of 270,000 people living in the affected area, most received low doses of radiation from iodine. About 13,500 received a dose 1,300 times the amount considered safe for civilians. Approximately 1,200 children received doses far in excess of this number.
  • 1986 – International Nutronics of Dover, New Jersey and one of its top executives are convicted by a federal jury of conspiracy and fraud. Radiation remains in the vicinity of the plant, but the NRC says the levels aren't hazardous.
  • January 6, 1986 – At the Kerr-McGee nuclear fuel reprocessing plant in Gore, Oklahoma, a cylinder of nuclear material bursts after being improperly heated. One worker dies, 100 are hospitalized.
  • 1986 – The NRC revokes the license of a Radiation Technology, Inc. (RTI) plant in New Jersey for worker safety violations. A safety device to prevent people from entering the irradiation chamber during operation was bypassed. A worker received a near-lethal dose of radiation. RTI was cited 32 times. Violations also included throwing radioactive garbage out with the regular trash.
  • April 26, 1986 – The worst accident in the history of nuclear power occurred at the Chornobyl nuclear power plant located near Kiev, USSR (now part of the Ukraine). Fire and explosions resulting from an unauthorized experiment leave 31 dead in the immediate aftermath. Radioactive nuclear material is spread over much of Europe. Over 135,000 are evacuated from the areas around Chernobyl. Many of these areas remain uninhabitable for many years later.
  • June 6, 1988 – Radiation Sterilizers in Decatur, Georgia Reports a leak of cesium-137 at their facility. 70,000 medical supply containers and milk cartons were recalled. Ten employees were exposed, and three "had enough on them that they contaminated other surfaces" including their homes and cars. (according to Jim Setser at the Georgia Department of Natural Resources.)
  • October 1988 – At the nuclear trigger assembly facility at Rocky Flats in Colorado, two employees and a Department of Energy inspector inhale radioactive particles, causing closure of the plant. Several safety violations were cited, including uncalibrated monitors, inadequate fire equipment, and groundwater contaminated with radioactivity.
  • January 1989 – A fault was discovered to run under the Savannah River nuclear processing plants in Georgia to an underground aquifer providing drinking water to much of the southeast US. Nearby turtles had radioactive strontium of up to 1,000 times the background level.

1990s

  • January 23, 1990, Bruce A, Ontario, Canada - 12,000 litres of heavy water are accidentially dumped into the containment vault below the reactor when a software failure releases the brakes on a refueling machine.
  • November 24, 1992, Fuel Reprocessing Plant, Gore, Oklahoma - The plant closed after repeated safety and environmental violations. Its record during 22 years of operation included a 1986 accident that killed one worker and injured dozens of others, contamination of the Arkansas River and groundwater. It had been shut down the previous week by the Nuclear Regulatory Commission when an accident released toxic gas, causing thirty-four to seek medical attention. The plant had been shut down in 1991 when the water of a nearby construction pit had high concentrations of uranium. The government cited Carol Couch, the plant's environmental manager, for obstructing the investigation and falsifying documentation.
  • February 15, 1993, 18,000 litres of heavy water are spilled at the Darlington nuclear power plant in Canada.
  • 1997 - Georgian soldiers suffer radiation poisoning and burns eventually traced back to training sources abandoned, forgotten, and unlabelled at the collapse of the Soviet Union. One was a cesium-137 pellet in a pocket of a shared jacket which put out about 130 000× background at 1 m distance.[36]
  • May 1997, Hanford Engineering Works, Hanford, Washington - A 40 gallon tank of toxic chemicals exploded, causing a release of about 25,000 gallons of plutonium-contaminated water. Fluor Daniel Hanford Inc., was cited for violations of the Department of Energy's nuclear safety rules and fined $140,625. Violations included the contractor's failure to assure that breathing devices operated effectively, failure to make timely notifications of the emergency, and failure to conduct proper radiological surveys of workers, failure to assure adherence to "criticality" safety procedures. These procedures prevent the waste from acting like a reactor and generating more heat and radioactivity.
  • 1998 - Recycler Acerinox in Cadiz, Spain unwittingly melts scrap containing radioactive sources; the radioactive cloud drifts all the way to Switzerland before being detected.[37]
  • August 8, 1999, Department of Energy's Gaseous Diffusion Isotope Separation Plant, Paducah, Kentucky - The Washington Post reported that thousands of workers were unwittingly exposed to plutonium and other highly radioactive metals over a 23-year period. Workers were told they were handling uranium rather than the more toxic plutonium. They inhaled radioactive dust as part of a government experiment to recycle used nuclear reactor fuel.
  • September 30, 1999 - Japan's worst nuclear accident ever took place at a uranium reprocessing facility in Tokaimura, Ibaraki prefecture, northeast of Tokyo, Japan. The direct cause of the accident was workers putting uranyl nitrate solution containing about 16.6 kg of uranium, which exceeded the critical mass, into the precipitation tank, which was not designed to dissolve this type of solution and was not configured to prevent eventual criticality. This exposed workers and residents in the surrounding area to extremely high levels of radiation.

2000s

  • February 15, 2000 - The Indian Point II nuclear power plant in New York vented a small amount of radioactive steam when a steam generator failed.
  • June 2000, Portsmouth Gaseous Diffusion Isotope Separation Plant, Piketon, Ohio - U.S. Senator Mike DeWine (R-OH) led a field senate hearing to discover evidence about on and off-site contamination. Testimony indicated that the Piketon plant altered workers' radiation dose readings and worked with medical professionals to fight worker's compensation claims.
  • July 2000, Hanford Engineering Works, Hanford, Washington - Wildfires hit the highly radioactive "B/C" waste disposal trenches. Airborne plutonium levels were raised in the nearby cities of Pasco and Richland to 1,000 times above normal.
  • August 2000, Barents Sea. The Russian submarine Kursk sank after an apparent internal torpedo accident, killing 118. Russia recovered the submarine's nuclear reactor, and stated it had carried no nuclear weapons. Greenpeace, urging Russia to recover the reactor, states there are now ten nuclear reactors and over fifty nuclear warheads on the floors of the world's oceans.

Unconfirmed incidents

  • The (supposedly successful) Japanese program to develop nuclear weapons in World War II. The story is that a prototype was exploded in the China Sea, but the factory in Japanese Korea was not yet on-line when the U.S. began nuclear bombing of Japan. If so, there will be lots of radioactive waste.
  • Reports of glow slaves (intentionally irradiated unwilling nuclear laborers) in the U.S.S.R., China, India, Pakistan, N. Korea, and pre-world-war-II Japanese Korea.
  • British tests of enhanced-fallout nuclear weapons in Australia.
  • South African and Israeli nuclear programs, and radioactive emissions.
  • At-sea decommissionings (simple scuttlings) of naval nuclear reactors by the Soviet, British and French Navies.
  • Undocumented radiation releases in the U.S.S.R., France, India, China, Japan and Pakistan.

See also

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