Failure to close a valve at the Tsuruga processing plant allows over 4,000 gallons of highly radioactive water to leak from a storage tank onto the floor of the waste reprocessing building. The water escapes the building through a manhole cover and a crack in the floor to wind up in Urazoko Bay, where high levels of cobalt-60 and manganese-54 are later found in the bay's edible seaweed. The leak is not noticed for three hours. During that time, 56 plant workers are exposed, receiving an average dose of 10 mRem.

The accident is not disclosed to the public until 18 April. Shortly afterward, six officials of Japan Atomic Power Corporation, including the Tsuruga plant's director, are replaced because of their roles in the cover-up. It is also found that serious incidents have occurred previously at the plant.

Located in Buenos Aires, Argentina, the RA-2 Facility houses a low-power (the source says "essentially zero power") experimental reactor assembly. This can hold 19 fuel-element plates, but four of them are normally removed and two cadmium plates inserted for reaction-rate control. There is also a graphite reflector. The reactor vessel is filled with de-mineralized water for tests and is supposed to be drained during changes in fuel-plate configuration, or whenever people are in the room.

The reactor technician, a qualified operator with 14 years experience, is alone in the room making such a configuration change. The tank has not been drained. He inserts two new fuel-element plates while the cadmium plates are not installed. Criticality is apparently achieved during insertion of the second plate, since it is found partially inserted. The excursion yields approximately 4.5x10¹⁷ fissions. The operator's exposure, mostly on the upper right side of his body, is 2,000 rad from gamma rays and 1,700 from neutrons. He dies two days later. Two people in the control room receive doses of about 15 rad from neutrons and 20 from gamma rays. Six others receive smaller doses, down to 1 rad, and nine receive less than one rad.

El Señor Vicénte Soledo Alardín is a scrap dealer in Juarez, Mexico. Unfamiliar with the dangers of radioactive materials, he removes the source from a radiation therapy machine he has acquired. The source consists of 6,010 pellets of cobalt-60 encased in a tungsten shell. This shell is damaged during the dismantling process. When Sr. Alardín drives to the salvage yard Jonke Fénix to sell his prize, some of the pellets spill in the bed of his truck and onto the roads. Each of them reportedly contains 70 microcuries of isotope and can deliver a dose of 25 R/h at close range.

The junkyard operator is equally unfamiliar with radioisotopes. During processing, more pellets are scattered throughout the yard, contaminating 60 employees and most of the metal at the facility. Meanwhile, Sr. Alardín's truck is parked elsewhere for two months with a flat tire. It contaminates another 200 people who live and work nearby. Some of their exposures are the largest ever recorded in Mexico. The truck is later found to emit 50R/h at a distance of one meter.

Scrap from the junkyard is sold to a smelting facility, contaminating 5,000 tons of steel with an estimated 300 curies of activity. The steel is made into building materials and legs for kitchen tables. Some of it winds up in the U.S. and Canada. The situation is only discovered months later when a truck delivering building materials to Los Alamos National Laboratory takes a wrong turn and drives through a radiation monitor, setting off an alarm.

Using special airborne detection equipment loaned by the U.S. Department of Energy, the Mexican government locates hot spots along the roads used to transport the original source. In some cases the highways have to be torn up to recover pellets embedded in the road surface. Mexico also condemns 109 houses in the state of Sinaloa due to contaminated building materials. The incident prompts the U.S. Customs Service and the NRC to install radiation detection equipment at all major border crossings.

Note: If the rating and quantity for the pellets are correct, there's no way they can add up to 300 Curies. My guess is the rating for each pellet should be 7,000 µCuries. This allows for a loss of about one-quarter of the pellets on the way to Jonke Fénix.

At a fossil-fuel power plant under construction in Mohammedia, Morocco, iridium-192 sources are being used to radiograph welds. One of these sources, containing approximately 30 curies of iridium-192, apparently becomes disconnected from its drive cable and is not properly returned to its shielded container. Subsequently, a passing laborer notices the tiny metal cylinder on the ground and takes it home. During May and June of 1984, a total of eight persons, including the laborer and his entire family and some relatives, die with the clinical diagnosis of "lung hemorrhages." Other individuals also receive significant doses of radiation that require medical attention. Three severely exposed individuals are hospitalized at the Curie Institute in Paris and later released in apparently satisfactory condition.

It is initially assumed that the deaths are the result of poisoning. Only after the last family member has died is it suspected that the deaths might be due to radiation. The source is recovered in June 1984. Although the source container is marked by the internationally recognized radiation caution symbol, the source itself bears no markings.

There is no information available on the precautionary radiation surveys that may have been performed at the time of the incident. However, it is apparent from the stated facts that radiation surveys of the type described in the NRC regulations, if performed, would have disclosed the problem and may have prevented the incident.

The USS Kitty Hawk (CV-63) is struck during night operations by a surfacing Soviet Victor-I class nuclear-powered attack submarine in the southern Sea of Japan, approximately 100 miles west of mainline Japan, while en route to the Yellow Sea. The Kitty Hawk sustains a minor hole below the water line in an aircraft fuel tank on her starboard side and continues normal operations. The Soviet vessel is observed dead in the water with a dent across its aft deck. It is aided by the Soviet Kara class cruiser Petropavlovsk and later towed by a Soviet salvage vessel to the naval base at Vladivostok. U.S. Navy officers say there is no evidence of leakage from the submarine.

The Kitty Hawk and her carrier group are taking part in joint U.S.-Korean "Team Spirit 84" exercises. The submarine, along with Soviet surface ships, has been follwoing these exercises for several days. Navy officials report that, after simulating its destruction 15 times, carrier group ships break contact with the submarine to enter a new phase of maneuvers in which the Kitty Hawk attempts to evade the trailing Soviet surface ships. The submarine apparently loses track of the Kitty Hawk during this phase and surfaces in order to locate her, causing the collision.

A Soviet Victor-I class nuclear-powered attack submarine is badly damaged when it collides with a Soviet tanker in the Strait of Gibraltar. The collision rips off the twin-hulled submarine's bow section, exposing the sonar and torpedo-tube compartments. It proceeds to the Soviet anchorage at Hammament, Tunisia for emergency repairs, and returns to its home port on the Kola Peninsula in early October.

Reports are that the submarine was travelling in the "noise shadow" of the tanker to avoid detection while exiting the Mediterranean Sea. Jane's Defense Weekly notes that the alternating layers of cold and warm water in the narrow Strait make it likely for a submarine "to encounter sudden thermal gradients which make her porpoise upwards," and this is thought to be the cause of the accident.

The Fernald Uranium Plant, a 1,050-acre uranium fuel production complex 20 miles northwest of Cincinnati, Ohio is temporarily shut down after the Department of Energy discovers that excessive amounts of radioactive materials have been released through ventilation systems. Subsequent reports document the following discharges into the valley of the Greater Miami River over the previous thirty years:

• 39 tons of uranium dust released into the atmosphere;
• 83 tons of uranium dust released into surface water;
• 230 tons of radioactive substances released into pits and swamps;
• 5,300 tons of hazardous chemicals released into pits and swamps.

Significant quantities of the radioactives and other hazardous materials in those pits and swamps find their way into local groundwater.

In addition, 337 tons of uranium hexafluoride are found to be unaccounted for, their whereabouts completely unknown. Residents of the valley sue in 1988 and are granted a $73 million settlement by the government. Plant operations are not shut down permanently until 1989.

A container of highly toxic gas explodes at the Sequoyah Fuels Corporation uranium processing plant in Gore, OK. One worker dies when his lungs are destroyed; 130 others seek medical treatment. In response, the government fines the plant owner $310,000, citing poorly trained workers, poorly maintained equipment, and a disregard for safety and the environment.

Note: Sequoyah Fuels is owned at this time by Kerr-McGee. See also 13 Nov 1974 and 24 Nov 1992.

The Soviet nuclear-powered ballistic missile submarine K-219 (Project 667A Yankee-I class), patrolling submerged 480 miles east of Bermuda, suffers an explosion and fire in one of its ballistic missile tubes. The explosion kills three crew members and causes a leak in the missile compartment. The submarine surfaces and the second reactor, which was offline at the time of the accident, is quickly started up. Despite the fact that water is entering the missile compartment, a fire breaks out there. The water apparently causes an electrical short circuit, triggering a scram of one of the two reactors. Another life reportedly is lost "in the struggle to lower the control rods." The submarine begins to lose buoyancy as water enters the ballast tanks. When the second reactor breaks down, the crew is transferred to a rescue vessel. The captain and nine crew members remain in the conning tower until the bow begins to sink; then the ship is abandoned.

North American television and newspapers carry pictures of the stricken submarine with steam and smoke issuing from one of its missile tubes. General Secretary Mikhail Gorbachev sends President Reagan a private communication regarding the accident in advance of the public announcement on 4 October, assuring him that there was no danger of nuclear explosion, radioactive contamination, or accidental launch of nuclear missiles. U.S. forces sample the air and water around the submarine and detect no radioactivity. Their conclusion is that the explosion resulted from the missile's nitrogen tetroxide propellant interacting with water in the tube. The submarine sinks under tow at 1103 hours on 6 October in 18,000 feet of water about 600 miles northeast of Bermuda. Her captain is charged with crimes against the state, but Gorbachev orders the charges dropped.

The U.S. government releases 19,000 pages of previously classified documents which reveal that the Hanford Engineer Works in Richland, Washington is responsible for the release of significant amounts of radioactive materials into the atmosphere and the adjacent Columbia River. Between 1948 and 1966, Hanford discharged billions of gallons of liquids and billions of cubic meters of gases containing plutonium and other radioactive substances into the Columbia Basin environment. Although deleterious effects were noticed as early as 1948, all reports critical of the facility remained classified.

By the summer of 1987, the cleanup cost was estimated to be $48.5 billion. In July 1990, the Technical Steering Panel of the government-sponsored Hanford Environmental Dose Reconstruction Project released the following statistics: Of the 270,000 people living in the affected area, most received low doses of radiation from iodine, but about 13,500 received a total dose some 1,300 times the annual amount of airborne radiation considered safe for civilians by the Department of Energy. Approximately 1,200 children received doses in excess of this number, and many more received additional doses from contaminants other than iodine.

Note: Hanford is a bad deal that may fairly be called the American Mayak. But this report is not a clear explanation of the problem. See also May 1997 and July 2000.

The Russian Echo-II class nuclear-powered cruise missile submarine K-192 surfaces in the Norwegian Sea, about 60 nautical miles north-west of Senja in Troms, Norway, after a leak develops in the primary cooling system for one of its two reactors. The reactor is not immediately shut down, and the contaminated coolant is pumped into the sea. The crew supplies additional cooling water from the submarine's fresh water tanks. When this runs out, the newly arrived Soviet Northern Fleet service ship Amur takes over the task of cooling the reactor. Its core temperature starts to come down. The Amur also takes the waste water on board, pumping it into tanks designed for that purpose.

At this point the crew of K-192 try to seal the leaking pipe. Coolant flow from Amur is shut off in order to permit this. For reasons that are in dispute, the support ship is late in restoring the flow; when it is restored, the cold liquid fractures overheated fuel elements. Amur cannot handle the now heavily contaminated water, and again it is pumped into the sea.

Eventually the reactor is brought under control. K-192 returns to the Kola Peninsula under diesel power, arriving on 28 June. The submarine is laid up at the Ara Bay facility until 1994; then it is towed to Navy yard No. 10 at Skval. There it remains, still containing its damaged reactor and fuel elements.

Crew members working on repairs have received significant doses of radiation; they are later treated, but details are not available. Releases of radioactive iodine are detected in the areas immediately surrounding the accident location, and sometime later at a monitoring post at Vardø in northern Norway.

• experienced a broken valve which causes her to "plunge nose down." (May)
• accidentally snagged a tow cable of the tugboat Barcona, sinking the tugboat and drowning one of her crew. (14 June)
• become entangled in the net of the fishing boat Fortuna. Damage to the net is $2,000. No injuries are reported. (19 June)

A report by the Washington-based Nuclear Information and Resource Service shows that, of the 112 commercial nuclear power plants operating in the United States, 59 have not completed safety modifications required by the NRC in the wake of the Three Mile Island accident in 1979.

In addition, Congress is investigating allegations of bribery in the nuclear power industry. John Delcore, a worker who exposed poor safety practices at North East Utilities, was reportedly offered $15,000 for his silence. This may relate to the Millstone nuclear power plant in Waterford, CT. The Texas Utility Electric Company is also under investigation for bribes connected to problems at the Comanche Peak nuclear power plant.

A device used in the Caithness nuclear plant at Dounreay, Scotland to test radiation alarms is reported missing. Investigators discover it has not been seen for a month before that. Investigators suspect that the device, consisting of a steel tube and a glass bead of radioactive caesium-137, may have been stolen or sent to a local waste dump.

In response to a request from the Sunday Herald, Dounreay releases a copy of its internal report on the investigation into the loss in March 2005. This previously secret report describes an extensive search conducted of plant facilities. Personnel and vehicles entering and leaving the site were also examined, but there were gaps attributed to dead batteries in portable radiation monitors and to the lack of police resources. The United Kingdom Atomic Energy Agency informed the public in 1989 of the disappearance of the source, distributed photographs, and publicly appealed for information.

Addressing the possibility that the source had inadvertently been discarded with plant garbage, the report described a search of an industrial waste skip at Dounreay and of Langlands Quarry, a landfill site near Thurso that was formerly used by the UKAEA. These searches, however, found no trace of the missing source. The conclusion was that the source never went into the trash stream or is buried too deep in the landfill to be detected.

The report is very critical of safety procedures in effect at the time. It notes that although the lead pot in which the source was kept was checked as present every working day, its contents were not. This was "not untypical", the report says. In general, it describes inadequate controls, records and guidance and broken radiation monitoring equipment.

Sources at Dounreay confirmed that information about the source has never turned up in the intervening years. According to Dr Michael Clark, a scientist from the government's National Radiological Protection Board, the lost source could still cause radiation burns in close contact with the skin.

Lorraine Mann, from Scotland Against Nuclear Dumping, expressed concern over these facts and criticized current safety standards at the Caithness plant. UKAEA spokesman Colin Punler disagreed, saying "Our records show that new procedures were introduced to improve the control of sources."

As the Sunday Herald predicted two years ago, Dounreay is now facing prosecution for leaking hundreds of thousands of radioactive particles into the sea and onto beaches. But it is unlikely to end up in court for losing the radiation source because that occurred while the plant was still protected by Crown immunity.

In order to test the emergency shutdown system in a new reactor at Greifswald nuclear power plant in East Germany, three of the six cooling water pumps are shut off. When a fourth pump breaks down, the reactor overheats and some local fuel element damage occurs. Apparently the relay that is supposed to trigger shutdown on failure of this pump is sticking.

Note: This facility had serious accidents in 1974, 1976, and 1981. Worse, normal conditions at the plant include sinking foundations, miswired cables, missing equipment, drunken workers... a veritable textbook case of how not to build and run a nuclear plant. The Atom City description is not fully coherent; I'm looking for a better one.