11 Worst Nuclear Accidents

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atomic bomb explosion bikini atoll marshall islands 1946

11 Nuclear Disasters

Since the Manhattan Project began in the late 1930s, nations have experimented with nuclear power and fuel refinement. Unfortunately, there have been quite a few mishaps, accidents and tragedies. The International Atomic Energy Agency (IAEA) classifies these disasters on the International Nuclear and Radiological Event Scale, a seven-point scale ranging from one (an "anomaly") to seven (an "major accident"). We have compiled the worst 11.

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Windscale Pile, Great Britain—INES Level 5, 1957

Britain experimented with a side-loading, air-and-graphite cooled reactor in its race to build an atomic bomb. The reactor caught fire because the technicians had little experience handling superheated graphite. Failing to put out the fire with carbon dioxide, the reactor's technicians were eventually successful in killing the flames with water, according to one of the physicists. Over 16 tons of uranium fuel remains in the reactor; it will be decontaminated in 2037.

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Chernobyl, Ukraine—INES Level 7, 1986

The Chernobyl disaster caused 53 direct deaths, and countless chronic illnesses. Technicians were conducting experimental shutdowns when an unexpected power surge caused the containment vessel to burst and the building to explode. Radioactive clouds quickly spread across Europe. The estimated cost of containing the disaster was $235 billion. In 2011, Igor Gramotkin, former director of the Chernobyl Atomic Energy Station, claimed that it would take 20,000 years for the 19 miles surrounding Chernobyl to be habitable.

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Saint Laurent des Eaux, France—INES Level 4, 1980

In a graphite-annealing incident, the reactor at Saint Laurent experienced a brief heat excursion. France’s worst accident ever may have caused traces of plutonium to be left in the Loire River.

(Photo: Alain Jocard/Getty Images)

3 Mile Island, Pennsylvania—INES Level 5, 1979

According to the Nuclear Regulatory Commission, the worst nuclear accident in U.S. history occurred when a stuck relief valve, caused by control flaws and human error, allowed tons of reactor coolant to escape, thereby resulting in a partial meltdown. Forty thousand gallons of contaminated waste spilled into the Susquehanna River near Harrisburg, Pennsylvania.

(Photo: Jeff Fusco/Getty Images)

jaslovske bohunice slovakia reactor disaster

Jaslovske Bohunice, Slovakia—INES Level 4, 1977

According to the World Nuclear Association, Slovakian scientists failed to properly operate this reactor by forgetting to take out contaminated silica packs—thereby causing fuel rods to overheat. In attempting to cool the machine, the entire reactor was contaminated. It will be fully decontaminated in 2033.

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Chalk River, Canada—INES Level 5, 1952

The first nuclear reactor located outside of the U.S. experienced an accident two years after opening. A combination of mechanical problems and human error led to a power surge and a loss of reactor coolant. This resulted in a hydrogen explosion in the reactor. The reactor vessel roof was blown off and 4,500 tons of radioactive water pooled in the basement.

(Photo courtesy of Canadian Nuclear Association)

Fukushima, Japan—INES Level 7, 2011

Following the devastating 9.0 Tohoku earthquake and tsunami, power outages caused the reactor coolant pumps to stop—a crippling problem considering the backup diesel generators were destroyed in the tsunami. Reactor One overheated, causing a hydrogen explosion and the roof to blow off. Reactors two and three experienced full meltdown as well. Luckily reactors four, five, and six were all off. Because it is the most recent accident, the IAEA Fukushima page continues to provide constant updates.

(Photo: AFP/ Getty Images)

Kyshtym, Russia—INES Level 6, 1957

In the race for the atomic bomb, Russia was fast and furious in its building of an unmapped nuclear fuel processing plant in what is now Ozyorsk. Ignorant of many safety precautions, the technicians were essentially helpless when a coolant tank broke. Eighty tons of contaminated coolant quickly evaporated from the reactor heat, causing an ammonium nitrate explosion with the force of 100 tons of TNT. The 160-ton containment lid was blown off and radioactive waste spread over 350 kilometers of the Eastern Urals.

(Photo: Courtesy of Furman)

Tomsk, Russia—INES Level 4, 1993

The reprocessing plant at Tomsk-7, a secret city in Siberia known today as Seversk, is a prime example of nuclear waste stupidity. The cleaning of an underground tank with nitric acid resulted in an explosion that blew off the top of the reprocessing plant, causing a fire and releasing a cloud of nuclear waste, according to the International Atomic Energy Agency.

(Photo: Courtesy of Global Security)

Tokaimura, Japan—INES Level 4, 1999

Workers preparing a U-235 fuel for the Joyo Reactor ditched proper procedure for speed—instead of pouring excess fuel, they dumped it—causing the containment tank to overfill. Three workers were exposed to high levels of radiation and two of them died in the months following the accident, according to an incident report by System Dynamics.

(Photo: Courtesy of Penn State)

Fleurus, Belgium—INES Level 4, 2006

In a facility that used cobalt 60 to irradiate medical devices, a worker noticed a radiation monitor alarm going off and went to close the door of the containment cell. The hydraulic device lowering the cobalt 60 into a pool was jammed. In the 20 seconds that the worker spent in the cell, he was exposed to 440 REMs of radiation. For comparison, the average person is exposed to a little over .001 REM during a chest x-ray, according to the U.S. Department of Energy. The worker was later admitted to the hospital for radiation poisoning and thankfully survived.

(Photo: Courtesy of Google Earth)

Should the United States abandon nuclear power? Are the risks worth the rewards?

Andrew Freeman is a California native with a degree in history from UCLA. He’s covered a wide range of topics for TakePart, but is particularly interested in politics and policy. Email Andrew |@natureofdabeast