List of nuclear accidents

From Academic Kids

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Pathways from airborne radioactive contamination to man

This is a list of notable accidents involving nuclear material. In some cases, these incidents involve people being injured or killed due to the release of radioactive contamination. Most incidents involve accidental releases that have caused contamination, but had no other immediate effects. Some incidents only had the potential to release radioactive material, and are included because of the tensions such incidents caused (collisions between nuclear-powered submarines, for instance). Due to government and business secrecy, it is difficult to determine with certainty the extent of some events listed below or, occasionally, whether they happened at all.

An accidental detonation of a nuclear weapon has never happened. For an implosion assembly weapon this risk is lower, because it would require the precisely synchronized simultaneous detonation of its numerous explosive lenses. For a gun-assembly weapon the risk is higher.


Before 1950

  • 1904Menlo Park New Jersey During the early years of X-ray experimentation Thomas Edison’s work on the fluorescence of different materials under X-ray bombardment led to his invention of a practical fluoroscope in 1896. A glassblower named Clarence Madison Dally worked for Edison forming X-ray tubes. He was known to test many of the tubes on his bare hands. In 1896 Dally received a severe X-ray burn, yet he seemed to recover and continued to work for another two years in the X-ray lab. Soon after, he developed skin cancer in both hands that spread quickly. Eventually it required amputation of both of his arms. Dally died of skin cancer in 1904. He is the first person known to die from X-ray exposure. In 1903 Edison decided to stop research on high energy ionizing radiation. He also refused to patent the fluoroscope, so it could freely benefit mankind.[1] ([2] ([3] (
  • December, 1941Germany While conducting an experiment in fast fission Werner Heisenberg and his colleague Robert Doepel were to learn first hand the pyrophoric nature of powdered uranium metal. An assistant causes a uranium fire while transferring uranium powder to a reaction vessel. The fire spread to other uranium stored close by. The fire was eventually smothered but the next morning smoldering uranium was uncovered during clean up. This accident outlined the need to perform future powdered uranium transfers in an inert atmosphere. [4] ( pg 130[5] (
  • June 24, 1942Leipzig Germany Heisenberg and Doepel had an explosion in the Leipzig L-IV atomic pile, which resulted in a major fire. This occurred shortly after L-IV demonstrated Germany’s first signs of neutron propagation. The nearly one ton device was in the process of being checked for a possible heavy water leak to the core. During the investigation air was accidentally introduced into the reactor's uranium powder core which in turn burst into flames. Despite all attempts to extinguish the crude reactor, the fire caused the heavy water jacket to boil, eventually generating enough steam pressure to blow the reactor apart. A spray of burning uranium particles were scattered throughout the lab, igniting a major facility fire. [6] ( pg 137-132[7] (
  • May 21, 1946Canadian physicist Louis Slotin manually assembled a critical mass of plutonium while demonstrating his technique to visiting scientists at Los Alamos and suffered a fatal criticality accident. The device consisted 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. Slotin died on May 30 from massive radiation poisoning, with an estimated dose of 1000 rads (rad), or 10 grays (Gy). While none of the seven observers received a lethal dose, two died suffering symptoms of radiation poisoning a few years later. In the movie Fat Man and Little Boy, John Cusack played a combination of Harry K. Daghlian and Louis Slotin. [10] (


  • August 5, 1950 – A nuclear-armed B-29 Superfortress had problems during take off from Fairfield-Suisun Air Force Base in California. The emergency landing ended in a fiery crash. A fire fighting team was dispatched in an attempt to rescue the crew. In the midst of the rescue effort the intense fire detonated over 10,000-pounds of high explosive used in the primary portion of the nuclear weapon killing 19 people. The explosion formed a twenty-yard crater across in the runway. One of the people killed in the rescue attempt was Gen. Robert F. Travis for whom the base is now named.
  • May 19, 1953 – The United States government detonated the 32-kiloton of TNT (130 TJ) bomb "Harry" at the Nevada test site. The bomb later gained the name "Dirty Harry" because of the tremendous amount of offsite fallout generated by the bomb. [16] ( Winds carried fallout 135 miles (220 km) to St. George, Utah, where residents reported "an oddly metallic sort of taste in the air." [17] ( A 1962 AEC report found that "children living in St. George, Utah, may have received doses to the thyroid of radioiodine as high as 120 to 440 rads" (1.2 to 4.4 Gy). [18] (
  • March 1, 1954 – During the early morning of March 1st, a Japanese Fishing boat, the Daigo Fukuryu Maru, or "Number 5 Lucky Dragon," and its crew witnessed what they believed to be the sun rising to the west of them as they sailed in the Pacific Ocean. In fact, they were witnessing the 15 megaton of TNT (63 PJ) detonation of the hydrogen bomb "Castle Bravo" at the Bikini Atoll, 85 miles (140 km) away. Four hours later, white ash began to fall like snow onto the boat. Many of the crew members gathered the ash into bags as souvenirs. Before the evening was over, the entire crew had become ill. The 23 crew members were hospitalized in Japan, and one later died of kidney failure due to radiation exposure. The incident brought 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.) Fallout was enhanced by debris from coral dispersed by the explosion. The US issued an apology and paid 2 million US dollars in compensation. [19] ( Additionally, in the same incident, 64 natives of Rongelap Atoll were exposed for 50 hours to fallout that produced a whole-body radiation dose of 1.75 Sv, 28 residents of Rongerik atoll were exposed to doses of about 780 mSv before being permanently evacuated, 18 residents of Alininae atoll were exposed to 680 mSv for about 50 hours, and 157 residents of Utirik atoll were exposed to 140 mSv for about 55 to 75 hours.
First notice of radioactivity in the fallout was raised seven hours after the detonation, when fallout reached Rongerik atoll. A group of 28 service members working at the weather station on Rongerik, 160 miles (260 km) east of Bikini, began evacuating about 30 hours after the explosion.
  • 1955 – Unexpected wind shift dropped test fallout on Las Vegas, Nevada [20] (
  • November 29, 1955 – An operator's error destroyed a three-year-old experimental breeder reactor EBR-I. [22] ( [23] (
  • July 26, 1956 – A US B-47 practising landings at Lakenheath Air Base in Suffolk, England, skidded into a nuclear storage mound with three Mark VI bombs inside. The resulting fire was extinguished without sparking explosions, although a secret cable by U.S. 7th Airborne Division General James Walsh in Britain remarked that the bombs were "knocked about," and "Preliminary exam by bomb disposal officer says a miracle that one Mark Six with exposed detonators sheared didn't go." He was presumably referring to the possibility of a high explosive detonation and possible radiological contamination of the area, rather than a nuclear explosion. Accidental ignition of the explosives in a nuclear weapon is insufficient to trigger the nuclear explosion of an implosion assembly weapon, such as those involved in the accident, because this requires the precisely synchronised simultaneous detonation of its numerous explosive lenses (although it could detonate a gun-assembly weapon).
  • March, 1957– Employees of a Houston company licensed by the Atomic Energy Commission to encapsulate sources for radiographic cameras opened a can containing 10 pellets of Iridium192. Using a jeweler's lathe isolated inside a Plexiglas box and 33 inches (840 mm) of concrete, the two operators discovered that two of the pellets were powderized. Some of the dust escaped the containment facility. One of the workers, dressed in street clothes, left the area while another remained, working in lab clothes and wearing a respirator. The contamination was not discovered by company personnel for a month and not by the AEC for about five weeks. The incident was reported in Look Magazine in 1961. By then, at least eight private homes and seven automobiles had been contaminated by the spreading dust. Only the two workers were found to have suffered radiation burns. The widely reported incident, in the early days of AEC civilian licensing administration, reportedly led to families of the workers being alienated from neighbors, who feared contamination. Reports released by the Mayo Clinic four years after the accident found few of the radiological injuries claimed in widespread press reports, but failed to assuage public fears that followed publicity of the accident.
  • 1957Keleket Co.: A capsule of radium salt burst leading to a five-month decontamination that cost US$250,000. The capsule was used to calibrate the radiation-measuring devices produced there.
  • September 11, 1957 – A major fire at Rocky Flats weapon mill 27 km from Denver began in a glove box and spread through the ventilation system into the stack filters. Plutonium (among lesser evils) was released, but no one was sure how much; estimates ranged from 25 mg to 250 kg. [24] ( [25] ( [26] ( [27] (
  • September 29, 1957 – Cooling system failure results in a nuclear waste storage tank steam explosion at Mayak, a spent nuclear fuel reprocessing facility near Chelyabinsk, Russia. The explosion, estimated to have the same energy as 75 tons of TNT (310 GJ), releases some 20 MCi (700 PBq) and subjecting (by various estimates) 124,000 to 270,000 people to dangerously high levels of radiation. [28] ( Of these, only 7,500 were evacuated, most of them too late to prevent dangerous levels of exposure. Inadequate medical records mean that number of people that died as a result is unknown, but probably numbers hundreds. 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. Approximately 41,000 acres (166 km²) of the worst contamination region has been designated a 'nature reserve', where scientists study the effects of it on wildlife. The US government learnt of the accident but kept it secret to avoid turning public opinion against the fledgling US nuclear industry. The accident was revealed by the US government in 1977 as a result of the Freedom of Information Act, and only admitted by the Russian government in 1992.
  • October 812, 1957 – Windscale Pile No. 1 at Sellafield north of Liverpool, England, began an annealing process to release Wigner energy from graphite portions of the reactor. The reactor that burned was one of two air-cooled graphite-moderated natural uranium reactors at the site used for production of plutonium. Technicians mistakenly overheated the reactor pile because poorly placed temperature sensors indicated the reactor was cooling rather than heating, leading to failure of a nuclear cartridge, which allowed uranium and irradiated graphite to react with air. The nuclear fire burned four days, melting and consuming a significant portion of the reactor core. About 150 burning fuel cells could not be lifted from the reactor core, but operators succeeded in creating a fire break by removing nearby fuel cells. A risky effort to cool the graphite core with water eventually quenched the fire. The air-cooled reactor had spewed radioactive gases throughout the surrounding countryside. Milk distribution was banned in a 200 mile² (520 km²) area around the reactor. Over the following years, Pile No. 1 and neighboring Pile No. 2 were shut down, although nuclear decommission work resumed in 1990 and continued at least through 1999. The incident, similar in scale to the Three Mile Island meltdown, was later blamed for dozens of cancer deaths. [29] ( [30] ( [31] ( [32] (
  • 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 (145 km) N.E. of Rabat, Morocco. The Air Force evacuates everyone within 1 mile (1.6 km) 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 (2,200 m) 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. See Tybee Bomb for further information.
  • February 28, 1958 – At the US airbase at Greenham Common, England, a B-47E of the 310th Bomb Wing developed problems shortly after takeoff and jettisoned its two 1,700 gallon external fuel tanks. They missed their designated safe impact area and one hit a hangar whilst the other struck the ground 65 feet (20 m) behind a parked B-47E. The parked B-47E, which was fuelled with a pilot onboard and carrying a 1.1 megaton of TNT (4.6 PJ) B28 thermonuclear free fall bomb, was engulfed by flames. The conflagration took sixteen hours and over a million gallons of water to extinguish, partly because of the magnesium alloys used in the aircraft. The fire detonated the high explosives in the nuclear weapon and convection spread plutonium and uranium oxides over a wide area — foliage up to 13 kilometres away was contaminated with uranium-235. Although two men were killed and eight injured, the US and UK governments kept the accident secret — as late as 1985, the British Government claimed that a taxiing aircraft had struck a parked one and that no fire was involved. However two scientists, F.H. Cripps and A. Stimson, working for the Atomic Weapons Research Establishment at Aldermaston, independently discovered high concentrations of radioactive contamination around the base in 1960. Their secret report referring to the accident was declassified in 1996.
  • 1958Soviet 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 (1 m) 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 (20 m) wide and 30 feet (10 m) 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.
  • June 16, 1958 – A prompt neutron criticality accident occurred in the C-1 wing of building 9212 at the Oak Ridge Tennessee Y-12 complex. This accident was partially due to a lack of supervision during a transfer of material that was thought to be water from a safe geometry container into a 55-gallon drum of unsafe geometry. A supercritical portion of highly enriched uranyl nitrate was allowed to collect in the drum It is estimated that the criticality produced 1.3 x 10*18 fissions. Eight employees were in close proximity to the drum during the accident, one was within three to six feet the other seven ranged fifteen to fifty feet. Afterwards the plant employees indium foil badge dosimeters pointed to thirty-one people with a potential significant neutron dose. [34] (
  • 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.
  • November 20, 1959: A chemical explosion occurred in the radio-chemical processing plant at Oak Ridge National Laboratory in Tennessee during decontamination of processing machinery. The explosion caused extensive plutonium contamination to the building, to adjacent streets and to nearby building exteriors. The explosion was theorized to have occurred after hot nitric acid was exposed to decontamination fluids containing phenol that had been left in an evaporator after operators failed to water-wash the equipment clean of decontamination fluids. (Report ORNL-2989, Oak Ridge National Laboratory). Areas that could not be effectively cleaned in the following weeks were painted with bright warning paint or with concrete. Oak Ridge officials began using secondary containment structures for radio-chemical processing facilities following the accident, which resulted in no reported injuries to personnel. The accident resulted in the release of about 15 grams of plutonium 239.


  • October 13, 1960 – One of the most serious accidents involving a naval reactor occurred on a USSR Northern Fleet vessel. The incident was caused by a loss of coolant to the reactor, and is classified accordingly. The Project 627 – November class submarine K-8 was on exercise in the Barents Sea when a leak developed in the steam generators and in a pipe leading to the compensator reception. The equipment for blocking these leaks was also damaged such that the crew itself began the work of stopping the leak. They mounted a provisional system for supplying water to the reactor to ensure cooling of the reactor and thereby avoid the risk of a core melt in the reactor. Large amounts of radioactive gases leaked out which contaminated the entire vessel. The true activity of the gases could not be determined because the instrumentation only went to a certain level. Three of the crew suffered visible radiation injuries, and according to radiological experts in Moscow, certain crew members had been exposed to doses of up to 1.8 - 2 Sv (180 - 200 rem). [35] (
  • 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.
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SL-1 reactor being removed from the National Reactor Testing Station
At the National Reactor Testing Station in Idaho Falls, Idaho, the experimental SL-1 reactor had a criticality accident with a steam explosion and a severe dispersal of radioactive material, killing three workers at the installation. With the exception of Iodine131, most of the radiation was contained within about a three-acre (12,000 m²) area. Vegetation was contaminated with I131 at levels as high as 100 times background levels as far as 20 miles (30 km) from the reactor. Radio-iodine contaminated vegetation at more than double background levels more than 50 miles (80 km) from the reactor, including about a 50 mile (80 km) stretch along the Snake River near Burley and American Falls. The portable reactor had manually actuate-able 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. Investigators never concluded why the rod had been removed. One worker was found pinned to the ceiling by a control rod, apparently driven by the steam. The accident was discovered by those outside the reactor building when radiation and thermal alarms alerted fire crews and health physicists, who discovered radiation levels exceeding 200 mrad/h (2 mSv/h) hundreds of feet or meters from the reactor building. Emergency crews were at first unable to find either a fire or the workers, but encountered radiation levels as high as 1000 mrad/h (10 mSv/h) inside the reactor building. One of the three workers was removed from the building but died a few hours later. The other two bodies remained in the building for several days while hundreds of rescue workers initiated recovery operations. Of those recovery personnel, 22 received radiation exposures in the range of 30 to 270 mSv, according to 1961 Atomic Energy Commission reports. The reactor was dismantled and the 13 short ton (12 metric ton) core and pressure vessel was removed several months later.
  • January 24, 1961 – A B-52 bomber suffered a fire caused by a major leak in a wing fuel cell and exploded in mid-air 12 miles (20 km) north of Seymour Johnson Air Force Base, Goldsboro, North Carolina. The incident released the bomber's two Mark 39 hydrogen bombs. Five crewmen parachuted to safety, but three died—two in the aircraft and one on landing. Three of the four arming devices on one of the bombs activated, causing it to carry out many of the steps needed to arm itself, such as the charging of the firing capacitors and critically the deployment of a 100-foot (30 m) diameter retardation parachute. The parachute allowed the bomb to hit the ground with little damage. The fourth arming device — the pilot's safe/arm switch — was not activated and so the weapon did not detonate. The other bomb plunged into a muddy field at around 700 miles per hour (300 m/s) and disintegrated. Its tail was discovered about 20 feet (7 m) down and much of the bomb recovered, including the tritium bottle and the plutonium. However, excavation was abandoned because of uncontrollable flooding by ground water, and most of the thermonuclear stage, containing uranium, was left in situ. It was estimated to lie at around 180 feet (55 m). The Air Force purchased the land and fenced it off to prevent its disturbance, and it is tested regularly for contamination, although none has so far been found. See: [Broken Arrow: Goldsboro, NC].
  • July 4, 1961 – The Soviet Hotel-class K-19 submarine experiences a major accident after a reactor cooling system fails off the coast of Norway. The incident contaminates the crew, parts of the ship, and some of the ballistic missiles carried onboard, and several fatalities result. Reactor core temperatures reach 800 °C, nearly enough to melt the fuel rods, although the crew is able to regain temperature control by using emergency procedures. The movie K-19: The Widowmaker, starring Harrison Ford and Liam Neeson, tells a controversially fictionalized story of these events.
  • October, 1961 – On four occasions between mid-October 1961 and August 1962, United States Air Force Jupiter IRBM mobile missiles carrying 1.4 megaton (5.9 PJ) nuclear warheads were struck by lightning at their launch sites near the Gioia Del Colle Air Base, Italy. In each case, thermal batteries were activated, and on two occasions, tritium-deuterium "boost" gas was injected into the warhead pits, partially arming them. After the fourth lightning strike on a Jupiter IRBM, the U.S. Air Force placed protective lightning strike-diversion tower arrays at all of the Italian and Turkish Jupiter IRBM missiles sites. These Jupiter missiles are sometimes called "The Other Missiles Of October". Their deployment in Italy and Turkey prompted the Soviet Union to place its missiles in Cuba in 1962, causing the Cuban Missile Crisis.
  • December 10, 1961 – An underground nuclear test explosion unexpectedly releases clouds of radioactive steam, causing several New Mexico highways to be closed.
  • July 26, 1962 – Nuclear Test attempt Bluegill Prime from Johnston Island in the Pacific Ocean. Second failure to launch a nuclear weapon using the Thor IRBM missile. The payload consisted of two re-entry vehicles, one with an instrument pod, the other with the warhead. The missile engine malfunctioned immediately on ignition. Range safety fired the destruct system while the missile was still on the launch pad. The Johnston Island launch complex was heavily damaged and contaminated with plutonium. Three months of repairs and decontamination were necessary before tests could resume.
  • April 10, 1963 – The nuclear submarine USS Thresher (SSN-593) sinks east of Boston, Massachusetts, with 129 men onboard. 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 during 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 tertiary-loop cooling inlet, and that the reactor and its design were not responsible. The reactor was not recovered.
  • April 12, 1964 – The nuclear-powered navigation satellite Transit 5BN-3 fails to achieve orbit and burns up in the Earth's atmosphere.
  • April 21 1964 – A US nuclear-powered navigational satellite failed to reach orbital velocity and reentered the atmosphere 150,000 feet (46 km) above the Indian Ocean. The satellite's SNAP generator contained 17 kCi (630 TBq) of plutonium-238, which at least partially burned upon reentry. Increased levels of Pu238 were first documented in the stratosphere four months later. About 16 kCi (600 TBq) of Pu238 was estimated to have settled into the atmosphere by 1970. The EPA estimated the abortive launch resulted in far less Pu238 contamination to human lungs (0.06 mrem or 0.6 µSv) compared to fallout from weapons tests in the 1950s (0.35 mrem or 3.5 µSv).
  • July 24, 1964 – A criticality accident occurred at a plant designed to recover uranium from scrap material left over from fuel element production. The Wood River Junction facility was located in Charlestown Rhode Island. An operator (Robert D. Peabody) was in the process of precipitating low concentrations of uranium out of contaminated trichloroethane solvent. This process was carried out in containers of safe geometry (5-inch diameter, 11-liter volume). Due to the large amount of contaminated solvent being processed this operation was moved to an 18 inch diameter by 25 inch deep container that is an unsafe geometry for high concentration solutions. Since the process involved solutions of low concentration this lapse in safety was overlooked. Unfortunately a bottle of high concentration material was mistakenly added to the unsafe container causing a flash of Cherenkov radiation. The criticality resulted in a reaction of 1 x 10^17th fissions and an exposure of 10,000 rad which killed Mr. Peabody within 49 hours. Ninety minutes later a second excursion happened when the container’s stirring unit was shut off exposing a two man clean up crew to a reaction of 2 x 10^16th fissions. This was not discovered until later when their dosimeters were checked because the radiation alarm was still blaring from the first excursion. Their dose was estimated to be 60 rad for one of the men and 100 rad for the other, neither man showed an adverse effect to their exposure.[36] ( pg27[37] (
  • December 5, 1964 – A Minuteman 1B missile was on strategic alert at Launch Facility (LF) L-02, Ellsworth AFB, South Dakota. Two airmen were dispatched to the LF to repair inner zone (IZ) security system. In the midst of their checkout of the IZ system, one retrorocket in the spacer below the Reentry Vehicle (RV) fired, causing the RV/nuclear warhead to fall about 75 feet (23 m) to the floor of the silo. When the RV/nuclear warhead struck the bottom of the silo, the arming and fusing/altitude control subsystem containing the batteries was torn loose, thus removing all sources of power from the RV/nuclear warhead. The RV structure received considerable damage. All safety devices operated properly in that they did not sense the proper sequence of events to allow arming the warhead. There was no detonation or radioactive contamination.
  • December 5, 1965 – An A-4E Skyhawk airplane with one B43 nuclear weapon onboard falls off the USS Ticonderoga into 16,200 feet (4.9 km) of water off the coast of Japan. The ship was traveling from Vietnam to Yokosuka, Japan. The plane, pilot, and weapon are never recovered. There is dispute over exactly where the incident took place—the US Defense Department originally stated it took place 500 miles (800 km) off the coast of Japan, but US Navy documents later show it happened about 80 miles (130 km) from the Ryukyu Islands and 200 miles (320 km) from Okinawa. [38] (
  • 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 US gallons (150,000 L) 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 (20 km) off the coast. A search involving three months and 12,000 men recover it. During the ensuing cleanup, 1,500 metric 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. The motion picture Men of Honor (2000), starring Cuba Gooding, Jr. as USN Diver Carl Brashear, and Robert De Niro as USN Diver Billy Sunday, contained an account of the fourth bomb's recovery.
  • September 1966 – Plutonium fire at Livermore.
  • October 5, 1966 – A sodium cooling system malfunction at the Enrico Fermi demonstration nuclear breeder reactor on the shore of Lake Erie near Monroe, Michigan, caused a partial core meltdown. The radiation was contained. This incident was the basis of the controversial polemic We Almost Lost Detroit by John G. Fuller. The reactor core comprised 105 uranium oxide fuel assemblies, made of pins clad with zirconium. The accident was attributed to a piece of zirconium that obstructed a flow-guide in the sodium cooling system. Automatic sensors isolated the reactor building. No personnel were inside at the time. Workers succeeded in manually shutting down the reactor. Two of the 105 fuel assemblies melted during the incident, but no contamination was recorded outside the containment vessel. The 200 MW reactor was returned to full-power operational status in October, 1970.
  • Winter 1966-1967 (date unknown) – The icebreaker Lenin, the USSR's first nuclear-powered ship, suffers a major accident (possibly a meltdown) in one of its three reactors. It was rumoured that around 30 of the crew were killed. The ship was abandoned for a year to allow radiation levels to drop before the three reactors were removed, to be dumped into the Tsivolko Fjord on the Kara Sea, along with 60% of the fuel elements packed in a separate container. The reactors were replaced with two new ones, and she re-entered service in 1970.
  • April 1967 – A drought dries up Lake Karachay near Chelyabinsk, Russia. From 1951 onwards, the swampy 0.5 square kilometre lake was used as a dump for medium and high level nuclear waste from Chelyabinsk-40, part of the Mayak facility. Whirlwinds spread around 5 MCi (190 PBq) of contaminated lake sediment over approximately 1,800 square kilometres.
  • January 22, 1968 – 7 miles (11 km) 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 possession, 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.
  • April 11, 1968 – A Soviet Golf-class submarine sinks in about 16,000 ft (4900 m) of water, approximately 750 miles (1200 km) northwest of Hawaii's Oahu island. 80 sailors are killed in the incident. Several nuclear torpedoes and three nuclear ballistic missiles were onboard. (Parts of this vessel were later raised by the CIA and Howard Hughes' Glomar Explorer in 1974.) [39] (
  • 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.
  • May 24, 1968 – The nuclear submarine K-27 (Project 645) was out at sea. During sea trials, the nuclear reactor had operated at reduced power, and on May 24, power inexplicably suddenly dropped. Attempts by the crew to restore power levels failed. Simultaneously, gamma radiation in the reactor compartment increased to 150 R/h. Radioactive gases were released to the reactor compartment from the safety buffer tank, and radiation on board the submarine increased. The reactor was shut down, and approximately 20% of the fuel assemblies were damaged. The incident was caused by problems in the cooling of the reactor core The entire submarine was scuttled in the Kara Seain 1981. [40] (
  • August 27, 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. [41] (
  • December 8, 1968 – In Nevada, the 30-kt of TNT (125 TJ) "underground" Plowshare test Schooner leaks radiation which drifts across the Canadian border, a treaty violation. [42] (
  • December 9, 1968 – In Nevada, an underground test of nuclear explosives releases clouds of radioactive steam.
  • 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. The Colorado Committee for Environmental Information deployed scientists with sophisticated measuring equipment, putting officials on notice that the public now had the capacity to discover and report releases of radioactive substances. The committee's work in response to the fire discovered radioactive residue in areas near Rocky Flats that provided evidence of gradual build-up of radioactive compounds during the years of Rocky Flats operation.
  • November 15 or 16, 1969 – The USS Gato (SSN-615) reportedly collides with a Soviet submarine in the White Sea. A former crewmember later states that the Gato was struck in the protective plating around the vessel's reactor. No serious damage resulted, although the ship went on alert and prepared to arm a nuclear-tipped anti-submarine missile and nuclear torpedoes. [43] (


  • December 18, 1970 – The Baneberry underground test vents 6.7 MCi (250 PBq) through a fissure in the rock.[46] ( Fallout later drifts into Canada, violating the 1963 test-ban treaty.[47] (
  • 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 US gallon (11 m³) tank of radioactive water.
  • September 1972 – The PM-3A - 1250 KW nuclear reactor that had been in operation since March 1962 at the U.S. base at McMurdo Station, Antarctica, was shut down due to radioactive leaks. Throughout its 10-years of operations, it had repeated shutdowns and radiation leaks. The reactor was later shipped back to the United Sates, along with 101 drums of radioactive contaminated earth. A further 11,000 cubic metres of contaminated rock were also later removed. It was May 1988 before the site was decontaminated enough for unrestricted use.
  • 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).
  • August 1976 – An explosion at a Hanford, Washington, Plutonium Finishing Plant contaminated several workers. The plant converted plutonium nitrate solutions into metallic form for nuclear weapons production facilities. The explosion blew out a quarter-inch-thick lead glass window that shielded workers from radioactive materials. One 64-year-old worker was showered with nitric acid and radioactive pieces of glass. The worker inhaled the largest dose of americium-241 ever recorded. He inhaled about 500 times the U.S. government occupational standards for the element. The worker was placed in isolation for five months and given an experimental drug to flush the isotope from his body. By 1977, his bodies radiation count had fallen by about 80 percent. When the worker returned home, friends and church members avoided him. His minister finally had to tell people it was safe to be around him. He died of natural causes in 1987 at age 75. [48] (
  • 1977 – The Soviet K-171 accidentally releases a nuclear warhead while off the coast of Kamchatka. After a frantic search involving dozens of ships and aircraft, the warhead is recovered. [49] (
  • February 22, 1977 – The Czechoslovak nuclear power plant A1 in Jaslovske Bohunice experienced a serious accident during fuel loading. This INES level 4 nuclear accident resulted in damaged fuel integrity, extensive corrosion damage of fuel cladding and release of radioactivity into the plant area. As result the A1 power plant was shut down and is being decommissioned.
  • May 22, 1978 – Aboard the USS Puffer near Puget Sound, Washington, a valve was mistakenly opened, releasing up to 500 US gallons (1,900 L) of radioactive water.
  • 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 (60 cm) deeper than design, despite evident cracking. The incident drains about 100 million US gallons (380,000 m³) of radioactive liquids and 1100 short tons (1000 metric tons) of solid wastes, which settle out up to 70 miles (100 km) down the Rio Puerco[50] (
  • 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."[51] ([52] (


  • September 19, 1980 – An Air Force repairman doing routine maintenance in a Titan II ICBM silo in Arkansas 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 with enough force to blow off the two 740-short ton (670 t) silo doors and hurl the nine megaton of TNT (38 PJ) warhead 600 feet (180 m). The explosion kills an Air Force specialist and injures twenty-one other USAF personnel. [53] (
  • February 11, 1981 – A new worker inadvertently opens a valve and more than 110,000 US gallons (420 m³) of radioactive coolant liquid leaks into the containment building of the Tennessee Valley Authority Sequoyah 1 nuclear power plant in rural Tennessee. Eight workers are contaminated with radiation.
  • November 2, 1981 – At the US Submarine Pens in Scotland, a fully armed Poseidon missile is accidentally dropped 17 feet (5 m) from a crane while being transferred from a submarine to its tender.
  • July 1981 – Lycoming New York Nine Mile Point NPP unit 1 An overloaded RADwaste water tank was deliberately flushed into the RADwaste building sub-basement filling it to a depth of four feet. This overturned and spilled some of the approximately one hundred fifty 55 gallon drums that were stored there. These drums were filled with High-level solid radioactive waste. Over the next three months attempts were made to clean up the radioactive water. 50,000 gallons of lesser-contaminated water was discharged into Lake Ontario to make room in a proper container for the extremely contaminated basement water. By October all attempts were abandoned with one foot of water still on the floor. At this point the plant’s owner disclosed the 50,000-gallon “lesser” lake discharge to the NRC but failed to mention the flooded basement or spilled drums. Eight years later the nuclear industry’s own watchdog group the Institute of Nuclear Power Operations issued a secret report harshly criticizing the plant owners for the still flooded basement. This report was leaked to the media. After seeing the story on the news the NRC dispatched inspectors who found radiation levels approaching 500 Rem per hour in the basement. This plant was on the NRC’s heightened “watch list”, for other violations. NRC resident inspectors were stationed at the plant from 1981-1989 none of them knew a thing about the basement until the media alerted them.[54] ([ NRC Region 1 augmented inspection team (AIT) inspection report # (50-220/89-90) of the use of the Radwaste building sub-basement as a long term liquid retention facility at Nine Mile Point unit 1 Oct. 2, 1989 ]
  • 1982International 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, and the water entered Dover's sewer system. The Nuclear Regulatory Commission was only informed of the accident ten months later by a whistleblower. In 1986 International Nutronics and one of its top executives were convicted by a federal jury of conspiracy and fraud. Radiation remains in the vicinity of the plant, but the NRC says the levels are not hazardous.
  • August 8, 1982– While on duty in the Barents Sea, there was a release of liquid metal coolant from the reactor of the Project 705 Alfa class submarine K-123. The accident was caused by a leak in the steam generator. Approximately two tons of metal alloy leaked into the reactor compartment, irreparably damaging the reactor such that it had to be replaced. It took nine years to repair the submarine. [55] (
  • January 3, 1983 – The Russian Kosmos-1402 nuclear-powered spy satellite burns up over the South Atlantic.
  • February 25, 1983 – In Salem, New Jersey, the Salem Nuclear 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.
  • September 23, 1983Buenos Aires, Argentina A criticality accident took place at the RA-2 facility in an experimental test reactor. A technician was in the process of reconfiguring the Materials Testing Reactor (MTR) fuel plates. Although for safety purposes it was standard procedure to drain the water used as a moderator from the reactor vessel during fuel reconfiguration this time SOP was not followed. This omission along with other operational errors result in an excursion of 3x10^17 fissions, the operator absorbed 2000 rad of gamma and 1700 rad of neutron radiation which killed him two days later. Another 17 people outside of the reactor room absorbed doses ranging from 35 rad to less than 1 rad.[56] ( pg103[57] (
  • December 6, 1983Juarez Mexico, A local resident Vicente Sotelo Alardin improperly salvaged materials from a discarded radiation therapy machine. Unfamiliar with the dangers entailed in dismantling the unit he removed the radiation source encased in a tungsten shell. It was damaged in the process this spilled some of its contents in the bed of his truck and some on the road as he drove to sell it at the Jonke Fénix salvage yard. Unknown to him or the junk dealer it was filled with 6010 pellets of the isotope Cobalt - 60. Each pellet contained 70 microcuries of activity that could emit up to 25 röntgen per hr at close range. The container was breached further during its processing at the junkyard this scattered radioactive pellets and dust throughout the yard contaminating 60 employees and most of the metal in the facility with a dose of radiation. Mr. Alardin’s contaminated truck was later parked elsewhere in the city for two months with a flat tire where it contaminated another 200 people who lived and worked nearby with the largest radiation doses in Mexico’s public record. The truck was found to emit 50/R per hour at less than one meter. The junkyard’s contaminated scrap was trucked to another facility for smelting this in turn contaminated another 5000 tons of steel with an estimated 300 curies of activity. This material was sold for kitchen table legs and building materials some of which was sent to the U.S. and Canada. The discovery of this accident was an accident in itself, a truck delivering contaminated building materials months later to the Los Alamos National Laboratory became lost and accidentally drove through a radiation monitoring station setting off an alarm. The Mexican government with the help of special aerial detection equipment loaned by the U S DOE detected “hot spots” on the roads that were used to transport the original damaged radiation source. In some cases pellets were actually found embedded in the roadway. They also condemned 109 houses in the state of Sinaloa due to contaminated building material. This incident prompted the NRC and US Customs Service to install radiation detection equipment at all major border crossings. [58] ( [59] (
  • 1985-1987 A radiation therapy machine called Therac-25 has a software bug that gives massive overdoses of radiation to at least 6 patients, killing 5 of them.
  • August 10, 1985 – About 35 miles (55 km) from Vladivostok in Chazhma Bay, an Echo-class submarine has a reactor explosion, producing fatally high levels of radiation. Ten officers are killed, but the deadly cloud of radioactivity does not reach Vladivostok. [60] (
  • 1986 – The US Government declassifies 19,000 pages of documents indicating that between 1946 and 1986, the Hanford Site in Richland, Washington, released thousands of US gallons (several m³) of radioactive liquids. Of 270,000 people living in the affected area, most received low doses of radiation from iodine.
  • 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 Chernobyl nuclear power plant located near Kiev, USSR (now part of Ukraine). Fire and explosions resulting from an unauthorized experiment left 31 dead in the immediate aftermath. Radioactive nuclear material was spread over much of Europe. Over 135,000 are evacuated from the areas immediately around Chernobyl (or, in Ukrainian, Chornobyl) and over 800,000 from the areas of fallout in Ukraine, Belarus and Russia. About 4,000 miles² (10,000 km²) were taken out of human use for an indefinite time. The official death tolls range from 300 to 300 000 deaths, but many believe it's actually closer to 400 000. See Chernobyl accident.
  • May 4, 1986, – An experimental THTR-300 PBMR located in Hamm-Uentrop, Germany was touted as the beginning of a “new generation” of accident resistant reactor design. After the Chernobyl accident and graphite fire the West German government disclosed that on May 4 the 300-megawatt PBMR at Hamm released radiation after one of its spherical fuel pebbles became lodged in the pipe used to deliver fuel elements to the reactor. Operator actions to dislodge the obstruction during the event damaged the fuel pebble cladding releasing radiation into the environment. Radioactive fallout was found as far as two kilometers from the reactor due to the PBMR inherent lack of containment in its design. The fallout in the region was initially blamed on the Chernobyl accident, which happened nine days earlier. Scientists in the Freiburg area reported that as much as 70 % of the region’s contamination was not of the type released from the Chernobyl disaster, it was due to other sources. An attempt to conceal the reactor malfunction combined with mounting public pressure due to the recent Chernobyl accident caused the German government to order the reactor closed pending a review. Continued technical problems resulted in the unit’s full closure in late 1988. The government refused further funding in lieu of decommissioning the reactor.
  • October 3, 1986 – 480 miles (770 km) east of Bermuda, a Soviet Yankee I-class submarine experienced an explosion in one of its nuclear missile tubes and at least three crew members were killed. Thirty-four nuclear missiles and two reactors were on board. Soviet leader Mikhail Gorbachev privately communicated news of the disaster to U.S. President Ronald Reagan before publicly acknowledging the incident on October 4. Two days later, on October 6, the ship sank in the Atlantic Ocean while under tow in 18,000 feet (5.5 km) of water. [61] (
  • 1987 – In the Goiânia accident, scavengers broke open a radiation-therapy machine in an abandoned clinic of Goiânia, Brazil. They sold the kilocurie (40 TBq) caesium-137 source as a glowing curiosity. 400 were contaminated, four die.[62] (
  • June 6, 1988Radiation Sterilizers in Decatur, Georgia, reports a leak of caesium-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 un-calibrated monitors, inadequate fire equipment, and groundwater contaminated with radioactivity.
  • April 7, 1989 – The Soviet Komsomolets attack submarine catches fire about 300 miles (480 km) off the coast of Norway. 27 crew members escape, but the remaining 42 do not survive as the ship sinks. Two nuclear-armed torpedoes were on-board along with the vessel's nuclear reactor. [63] (
  • 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.


  • June 24, 1990Soreq, Israel An operator at a commercial irradiation facility bypassed the safety systems on the JS6500 sterilizer to clear a jam in the product conveyer area. He was under the false assumption that the rack of 42 stainless steel encased Co-60 rods (a radiation source of 12.6 PBq activity) had been lowered into a 5.5-meter deep pool of water used to shield personnel entering the product irradiation chamber. Unfortunately a box of product that had become misaligned on the conveyor system stopped the source rack on its way down. A misadjusted micro switch gave a false source down indication in the control room. The source down light was offset by the counter indicated blare of a radiation alarm. It was at this point that the operator should have consulted his supervisor and the facility’s radiation safety officer but he was in a hurry to get home. He chose to ignore the radiation alarm because it was known to give false readings in the past whereas the source down light had never been known to fail, this cost him his life. Upon entering the chamber he failed to see the source rack because boxes of product obstructed his line of sight. His eyes began to burn and his head started throbbing so he fled the chamber to summon help. The one to two minute exposure resulted in a whole body dose estimated at 10 Gy or more. His true dose is unknown because he failed to wear his dosimeter during the event. He died 36 days later despite extensive medical care. [65] (
  • September 27, 1991 – While testing a missile in the White Sea, the crew of a Soviet Typhoon-class submarine discovers a defect and surfaces. The missile starts burning upon contacting clear air and leaves its launch tube as a fireball is reported on deck. The ship dives to put out the fire. [66] (
  • October 26 1991Nesvizh Belarus An operator at an atomic sterilization facility bypassed the safety systems to clear a jammed conveyer. Upon entering the irradiation chamber he was exposed to an estimated whole body dose of 11 Gy with some portions of the body receiving upwards of 20 Gy. Prompt intensive medical care managed to keep him alive for 113 days after the accident.[67] (
  • November 24, 1992 – The Fuel Reprocessing Plant in Gore, Oklahoma, is 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 and 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 people 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.
  • April 6, 1993Tomsk Russia A major accident with a release of radiation occurred at the Tomsk-7 Siberian Chemical Enterprise plutonium reprocessing facility. This was due to a build up of pressure in a 34 cubic meter stainless steel reaction vessel buried in a concrete bunker under building 201 of the radiochemical works. The vessel contained a mixture of concentrated nitric acid, uranium (8757kg), plutonium (449g) along with a mixture of radioactive and organic waste from a prior extraction cycle. An effort was made to vent the excess pressure with little effect. It climbed steadily until it reached 5 atm. then it spiked to 18 atm. followed by an explosion which dislodged the concrete lid of the bunker and blew a large hole in the roof of building 201 releasing approximately 6GBq of Pu 239 and 30TBq of various other radio nuclides into the environment. Nineteen hundred forty six various employees were exposed to radiation as a consequence of the accident. The contamination plume extended 28 km NE of building 201, 20 km beyond the facility property. The small village of Georgievka ( pop. 200) was at the end of the fallout plume, but no fatalities or injuries were reported at either Tomsk-7 or in the surrounding countryside according to the IAEA. [70] (
  • 1995 – The EPA mounts a massive clean-up effort in Commerce Township, Michigan, after it was found that the attempted homemade breeder reactor built by David Hahn was leaking dangerous amounts of radiation, in excess of 1,000 times the background level. [71] (
  • November 17, 1996 – The Russian probe Mars 96 fails during launch and crashes back to Earth with an RTG on board. The location of the crash is disputed - either in the Pacific Ocean or in the mountains of Chile.
  • 1997Georgian soldiers suffer radiation poisoning and burns. They are eventually traced back to training sources abandoned, forgotten, and unlabelled after the collapse of the Soviet Union. One was a caesium-137 pellet in a pocket of a shared jacket which put out about 130,000 times background at 1 meter distance.[72] (
  • May 1997 – A 400 US gallon (1,500 L) tank which contained ~3 US gallons (11 L) of toxic chemicals explodes at Hanford Site in Richland, Washington, causing a release of about 25,000 US gallons (95 m³) of water from a ruptured fire sprinkler main. 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 (although they did operate correctly), failure to make timely notifications of the emergency, failure to conduct proper radiological surveys of workers (failure of an employee to follow established procedures), and failure to assure adherence to "criticality" safety procedures (even though the area that the flood occurred had no fissile material) which prevent the waste from acting like a reactor and generating more heat and radioactivity.
  • July, 1999 – A fire broke out during a waste procedure at Livermore when a technician failed to fully assess the bagged materials to be disposed, allowing bulk uranium to remain in the waste. The bag began glowing and starting to expand. The uranium had undergone spontaneous combustion and ignited other materials in the waste package.
  • August 8, 1999The Washington Post reports that thousands of workers at the Department of Energy's Gaseous Diffusion Isotope Separation Plant in Paducah, Kentucky, 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, 1999Japan's worst nuclear accident to date takes place at a uranium reprocessing facility in Tokai-mura, Ibaraki prefecture, northeast of Tokyo, Japan. The direct cause of the criticality accident was workers putting uranyl nitrate solution containing about 16.6 kg of uranium, which exceeded the critical mass, into a precipitation tank. This process was approved by management, yet was not submitted for regulatory approval on the basis that it would obviously be rejected; also the enrichment level of the fuel required a method that had not been used for a number of years, and most of the employees who worked on it had been downsized.The tank was not designed to dissolve this type of solution and was not configured to prevent eventual criticality. The incident exposes workers and residents in the surrounding area to extremely high levels of radiation. See also 5 yen coin.


  • February 15, 2000 – The Indian Point nuclear power plant's reactor 2 in Buchanan, New York, vents a small amount of radioactive steam when a steam generator tube fails. No detectable radioactivity was observed offsite. Con Edison is censured by the NRC for not following the procedures for timely notification of government agencies. Subsequently, Con Edison is required by the NRC to replace all 4 steam generators. Unit 2 is purchased by Entergy, Inc. on 9/6/2001.
  • July 2000 – Wildfires hit the highly radioactive "B/C" waste disposal trenches at Hanford Site in Richland, Washington. The radioactive material is not on the surface, but underground. No measurable airborne contaminants detected outside the Site boundaries. No radioactive contaminants detected in any of the surrounding cities (Richland, Pasco & Kennewick).
  • August 2000 – The Russian submarine Kursk sinks in the Barents Sea after an apparent internal torpedo accident, killing 118. Russia eventually recovers the submarine's nuclear reactor and states that the submarine had carried no nuclear weapons. Greenpeace, in an effort 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. The remains of the Kursk, including her reactors, were recovered in 2001 and scrapped.
  • December 2000 – According to Radiological Protection Institute of Ireland watches sold in France at the Carrefour store chain under the brand name “Trophy” were found to be contaminated with Co-60. Tests carried out by French officials on over 3000 Watches with the serial # T65007.3 found that almost 50% of them had radioactive adjustment hinges. This would give the owner an estimated 300 mSv of wrist exposure after a year of use, six times the public dose allowed in Europe. An investigation has been initiated at the point of manufacture in Hong Kong by the Chinese government to ascertain the contamination source. [74] (
  • May 2001 – Three radioisotope power sources RTG were stolen from lighthouses of Russia’s Defence Ministry on an island in the White Sea, in the area of the Kandalaksha nature reserve in the Murmansk region. This reserve is one of Russia's known centers of ecological tourism. Two looters of non-ferrous metals received severe doses of radiation. The "hot" RTGs were recovered and sent to VNIITFA in June 2001. From there, they were transported to the Urals chemical combine Mayak. The bill for all these works was footed by the government of the Norwegian province of Finnmark under an agreement with the administration of the Murmansk region as part of a bilateral program, which envisions decommissioning of RTGs at Russian lighthouses and replacing the radioactive devices with solar batteries. [75] (
  • February 9, 2002 – Two workers were exposed to a small amount of radiation and suffered minor burns when a fire broke out at the Onagawa Nuclear Power Station Miyagi Prefecture. The fire occurred in the basement of reactor #3, during a routine inspection when a spray can was punctured accidentally igniting a sheet of plastic [76] (
  • March 5, 2002 – During an extended power uprate test designed to extend the power efficiency of aging BWR reactors the Quad Cities Nuclear Generating Station unit 2 (Illinois) began to shake itself apart. On March 29 the plant was manually shut down due to high vibrations causing leaks in the main turbine control system. Unit 2 had a restart on April 2, but vibration broke a main steam pipe drain line. The line was repaired and the restart resumed but by June 7 the main steam lines were showing unexplained aberrations. On June 18 it became obvious that the power uprate was causing damage so the power was reduced but the damage had been done. Once again the plant was taken offline for repairs on July 11. The problem was traced to a hole in the steam dryer - it was repaired and braced, then unit 2 was restarted on July 21, 2002. The steam dryer failed again on May 28, 2003 with a ¾ in x 9 ft (6 mm by 2.7 m) crack. These two failures have not deterred the NRC from continuning the EPU program and offering these extended power uprates to other aging BWR . [77] ([78] (
  • March 2002 – Workers at the Davis-Besse nuclear plant in Ohio were replacing a cracked Control Rod Drive Mechanism (CRDM) nozzle when they discovered a football-sized hole eaten 6 inches (150 mm) into the steel outer shell of the reactor vessel head. This only left a 3/16 inch (5 mm) stainless steel liner to hold back 87,000 U.S. gallons (330,000 liters) of radioactive water at a pressure of 2000 psi (14 MPa). Later investigation of the stainless steel liner found the beginning of a crack [79] ( The damage occurred over a period of nearly six years due to a cracked CRDM nozzle leaking borated water (weak acid) onto the reactor head. On April 22, 2005 the Nuclear Regulatory Commission[80] ( proposed a 5.4 million dollar fine against FirstEnergy, the plant owner, for failure to clean the reactor vessel in 2000. System engineer Andrew Siemaszko was also banned from working in the industry for five years due to his falsification of reactor vessel cleaning logs in May 2000. An excellent drawing of the problem can be found on the NRC website. [81] (
  • February, 2003Oak Ridge Tennessee Y-12 facility. During the final testing phase of a new salt less uranium processing method the test experienced a small explosion followed by a fire. The explosion occurred in an unvented vessel containing unreacted calcium, water and depleted uranium, an exothermic reaction amongst these articles generated enough steam to burst the container. This small explosion breached the glovebox where it was stored. Air filtered into the damaged glovebox igniting some loose uranium powder (uranium is pyrophoric) starting a fire that slightly contaminated three employees. A year later BWTX, a partnership of BXW Technologies and Bechtel National was fined $82,500 for the accident.[82] ( [83] (
  • March 12,2003 – Military personnel at the Leningrad Naval Base discovered a vandalized lighthouse near Kurgolovo. The RTG was looted for scrap metal by thieves. The "hot" strontium capsule melted the ice and went down to the sea floor. But even though the ice covering the spot where the radioactive heat source sank was one meter thick, the gamma radiation exposure dose rate directly above the sunken unit reached over 0.3 Sv/h. A similar case happened in the Leningrad region in 1999. An identical lighthouse was found completely destroyed, and its radioactive power element discarded at a bus station in the city of Kingisepp, 50 kilometres away from the crime scene. Three people who the police established were the perpetrators of the 1999 episode died from radiation poisoning. [84] (
  • August 16, 2003 – According to a report by GAN's branch of the Far Eastern Interregional Territorial District, the monitoring commission, while inspecting RTGs located on the Arctic shore of the Chukotka Autonomous District, found one RTG in a state of utter dilapidation, on the Cape of Navarin in the Bering region. The level of the so-called exposition dose on the surface of the generator was as high as 15 R/h. The commission also concluded that a release of radioactive substances into the surrounding environment may have taken place. The commission found out, that the RTG "self-destroyed as a result of some, not specified yet, inner impact". That was stated in a letter 04-05\1603, sent by VNIITFA director Nikolay Kuzelyov and Ministry of Defence representative A.Kunakov to the Minatom. In July 2004 a second inspection of the RTG at the Cape of Navarin was carried out. The check-up showed, that radiation situation had worsened, gamma radiation had rose to 87 R/h, but the main observation was that strontium-90 began to leak into the environment. [85] (
  • September 2003 – Northern Fleet service personnel discovered a theft of the metals used in the RTG biological protection system casing at a nuclear powered lighthouse on the small island of Golets. The door inside the lighthouse had been forced. The lighthouse contained a particularly powerful RTG with six RHS-90s, which were not taken. Common materials of value stolen from dismantled RTG's are stainless steel aluminum and depleted uranium.[86] (
  • November 12, 2003 – The Hydrographic Service of the Northern Fleet CIS found a ravaged Beta-M RTG located on the Bay of Oleniya. This RTG was one of nearly 1000 RTG’s in use by the CIS to power one of the many nuclear lighthouses and navigational aids they maintain in the Arctic regions. This unit had been damaged and looted by scrap metal thieves. The radioisotope heat source—a strontium capsule—was found sunk in about three meters of water near the shore. The Beta–M system is common in about 700 of the units in service. Its case is not welded and can be dismantled easily with hand tools. The Beta-M has a power of 230 watts. The weight of this RTG is 560 kg. The weight of the radioactive part is around 5 kg, it contains 1.3 to 1.5 PBq (35,000 to 40,000 Ci) of activity. The radioactivity of the RTG fuel element at the distance of 0.02 to 0.5 meter is 800 to 1000 roentgens (0.21 to 0.26 C/kg) per hour.([87] (
  • November 13, 2003 – The same inspection team found a completely dismantled RTG of the same Beta-M type, used to provide electricity to the navigation mark No 437, located on the Island of Yuzhny Goryachinsky in the Kola Bay. The generator's radioactive heat source was found on the ground near the shoreline in the northern part of the island. The incident was classified as a radioactive accident. [88] (
  • August 9, 2004 – An accident in the nuclear power plant of Mihama, in the Fukui prefecture 320 km northwest of Tokyo, causes five deaths and seven injuries, becoming the deadliest nuclear power plant accident in Japan. The cause of the accident was a leak of non-radioactive steam in the reactor number 3 building. The power plant's operator recognized a defect of control procedures in its installations. The broken pipe did not meet the security norms. Local authorities announced that no radioactive leaks occurred outside of the building.
  • September 10 2004Zemlya Bunge, Novosiberian islands, Yakutia. Two Radioisotope thermoelectric generators — Numbers 4 and 5 of the "Efir-MA" model produced in 1982 — were being flown from the "New Siberia" island lighthouse off the Northeastern arctic coast of Siberia. They were suspended by cables below a helicopter so they could be taken to the Russian polar station at Bunge. The helicopter flew into heavy weather and the crew was forced to drop the two RTGs from a height of 50 meters onto the tundra at Zemlya Bunge island, 112 kilometres from the Russian polar station at Sannikova. According to the nuclear regulators, the impact compromised the RTGs' external radiation shielding. At a height of 10 meters above the impact site, the intensity of gamma radiation was measured at 4 milliSieverts per hour. It is reported that the radiation leak was triggered in the incident because the RTGs were being flown without special outer transportation casks. The State Hydrographic Service of the Ministry of Transportation, which owns the RTGs, was therefore in breach of International Atomic Energy Agency regulations. The RTGs can be retrived no earlier than summer 2005. [89] (
  • January 8, 2005 – The U.S. nuclear powered and nuclear armed submarine U.S.S. San Francisco struck an uncharted undersea mountain near Guam while sailing submerged at high speed. One crew member died from injuries related to the collision. The bow of the submarine was severely damaged. No radioactive material was released in the accident. The submarine is expected to be out of service for many months while repairs are being made. [90] (
  • March 26, 2005 – The Scottish Environment Protection Agency SEPA has been monitoring the sporadic discovery of radioactive spent fuel fragment contamination on public beaches in the area of the Dounreay nuclear facility. The Dounreay site is in the process of decommissioning it’s facilities, which contain 3 power reactors along with a fuel manufacturing and fuel re-processing plant. The problem was first detected in 1984 and was seen as an isolated incident at the time but a second particle was found in 1997 at Sandside[91] ( This prompted the formation of the Dounreay Particles Advisory Group DPAG to investigate the true extent and cause of these isolated off-site particle emissions. [92] ( Upon further review likely methods of particle generation, dispersion and transport routes were identified. [93] ( In Dec. 2000 a particle was found buried 1 cm in the soil near Dounreay castle adding an unforeseen piece to the puzzle. Early findings pointed to a transport chain based on improper drain routes allowing radioactive effluents access to “non-active” drains running to the sea. The finding of a particle well outside the influence of the sea opens the possibility of air, man or animal as a concurrent transport mechanism. This moves SEPA to request further investigation into alternate transport methods by the UKAEA [94] ( SEPA is aware that Dounreay is the only nuclear facility in Scotland discharging radioactive effluent without a final particulate filter in operation (since the late 50’s). Filtering will be required by SEPA in the future and in the interim Dounreay’s discharge permit has been reduced by a factor of 4.5 to 270 depending on the process involved to lower the chance of further particle transport. [95] ([96] ( SEPA has required UKAEA to routinely monitor Sandside Bay, the Dounreay Foreshore, Crosskirk, Brims Ness, Scrabster and Thurso Beaches. This program recently turned up another fuel fragment on Dunnet beach in March 2005[97] ( SEPA now requires the UKAEA to monitor the degree of particle contamination on the seabed in an effort to understand the extent of the off shore contamination.
  • April 19, 2005Sellafield, UK. Enough nuclear waste "to half fill an Olympic-size swimming pool" leaked from a cracked pipe into a "huge stainless steel chamber", at the Sellafield reprocessing plant and lay undetected for three months. The leak was reported by The Guardian on May 9 and subsequently reported on BBC News [98] ( [99] ( According to its story the powerplant workers noticed a discrepancy in the amount of fuel going into pipes conducting the waste to a set of centrifuges and the amount of fuel arriving at the centrifuges on April 19. News releases about this incident, issued by the company which operates the plant, can be found at Sellafield News Release 1056 ( and British Nuclear Group Press Release 27 May ( The amount of liquor stated in these news releases, and more generally by the media, is 83m3. The volume of an olympic size swimming pool, mentioned as a comparator in several media articles, is 2,500m3. n:Nuclear fuel leaks at Sellafield facility on Cumbrian coast, England
This section needs to be expanded. Please edit this page ( to add any missing incidents.

See also

External links


fr:Liste des accidents nucléaires ja:原子力事故 fi:Luettelo ydinonnettomuuksista


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