On March 11, 2011, an earthquake measuring 9.0 on the Richter scale struck Japan, bringing a destructive tsunami along with it. One of the sites most affected by the devastation was the Fukushima Daiichi nuclear power plant, which experienced a partial meltdown two days after the quake.
The incident is being called the worst nuclear accident since the 1986 disaster at Chernobyl, and it has shown few signs of slowing down.
Click ahead to see 11 other history-making nuclear disasters.
By Daniel Bukszpan, Special To CNBC.com
Posted 16 Mar 2011
On April 26, 1986, a reactor at the Chernobyl power plant in Ukraine exploded, causing the worst nuclear accident the world has seen. It sent a plume into the atmosphere with radioactive fallout that was 400 times greater than that released in the atomic bombing of Hiroshima. The plume drifted across much of the western Soviet Union. Parts of Eastern, Northern and Western Europe were also affected.
Fifty people were killed at the reactor site at the time of the accident, but the number of people across Europe who found themselves in the path of the radioactive plume is anybody’s guess. A report from the World Nuclear Association (http://world-nuclear.org/info/chernobyl/inf07.html) claims that over one million people may have been exposed to radiation. However, the full extent of the damage is unlikely to ever be known.
Until March 2011, the worst nuclear accident in the history of Japan took place at a uranium facility in Tokaimura on September 30, 1999. Three workers were attempting to mix nitric acid and uranium to form the fuel uranyl nitrate. However, the workers unknowingly used seven times the allowable limit of uranium, and the reactor couldn’t stop the solution from reaching critical mass.
The three technicians were exposed to massive gamma and neutron radiation poisoning, which killed two of them. More than 70 other workers received high doses of radiation as well. After an investigation, the International Atomic Energy Agency saidthat the accident had been caused by "human error and serious breaches of safety principles."
The worst nuclear accident in U.S. history took place on March 28, 1979 at the Three Mile Island plant in Pennsylvania. A cooling system failed, causing a partial meltdown, but a full meltdown was averted and there were no fatalities. However, despite the positive outcome and despite the passage of more than 30 years, the incident remains fresh in the minds of those who are old enough to remember it.
The effect of the accident on the U.S. nuclear power industry was major. The meltdown gave many Americans second thoughts about the risks of using nuclear power, and the construction of new reactors, which had been steadily increasing since the 1960s, slowed substantially. Over 50 nuclear plant construction projects were cancelled in just four years, and the number of ongoing projects declined from 1980 until 1998.
One of the worst nuclear contamination incidents in the world took place in Goiania, Brazil. A radiotherapy institute in the city had relocated, leaving behind a teletherapy unit that still contained cesium chloride.
On September 13, 1987, two scavengers found the unit, carted it away in a wheelbarrow and sold it to a junkyard. The owner invited friends and family to see the glowing blue material inside, inadvertently exposing them to radiation. All of them then went their separate ways and irradiated friends and family all over the city.
In all, 245 people were exposed to radiation and four people died. According to Eliana Amaral of the International Atomic Energy Agency, one good thing came out of the catastrophe."Before the 1987 accident… there was no awareness that sources must be controlled from ‘cradle to grave’ and to prevent the public accessing them. After the accident these concepts were fostered."
On July 4, 1961, the Soviet submarine K-19 was in the North Atlantic Ocean when it developed a radioactive leak. It had no coolant system in place to stop the reactor from overheating and exploding, so with no other options, the crew entered the reactor compartment and fixed the leak, exposing themselves to levels of radiation in the process that were certain to kill them. All eight crew members who had fixed the leak died of radiation poisoning within three weeks of the incident.
The rest of the crew, the submarine and the ballistic missiles that it carried also became contaminated. When K-19 met up with the submarine that had intercepted its distress call, it was towed to base, which it contaminated. Then, as it was repaired over the course of two years, the surrounding area and the repair workers also became contaminated. Twenty of the submarine’s original crew also died of radiation sickness over the next few years.
In the years following World War II, the United States was the foremost nuclear power in the world. In an effort to catch up, the Soviet Union quickly built nuclear power plants and cut corners in order to keep pace.
The Mayak plant near the city of Kyshtym had a tank with a substandard cooling system as a result, and when it failed, the increasing temperature caused an explosion that contaminated almost 500 miles of the surrounding area.
Initially, the Soviet government didn’t disclose what had happened, but one week later they had little choice. 10,000 people were evacuated from the area when some began to show signs of radiation sickness. Although the Soviet government refused to disclose any information about the accident, a study in Radiation and Environmental Biophysicsestimates that at least 200 people died from exposure to radiation. The Soviet government finally declassified information about the disaster in 1990.
On October 10, 1957, Windscale became the site of the worst nuclear accident in British history, and the worst in the world until Three Mile Island 22 years later. A facility had been built there to produce plutonium, but when the US successfully designed a nuclear bomb that used tritium, the facility was used to produce it for the UK. However, this required running the reactor at a higher temperature than its design could sustain, and it eventually caught fire.
Operators at first worried that extinguishing the flames with water would cause a hydrogen explosion, but ultimately gave in and did so as the crisis escalated. It worked, but not before a sizeable amount of radiation had been unleashed into the surrounding area. A 2007 studyestimated that the incident had led to over 200 cases of cancer in the surrounding population.
The Stationary Low-Power Reactor Number One, or SL-1, was a nuclear reactor located in the desert forty miles outside of Idaho Falls, Idaho. On January 3, 1961, the reactor exploded, killing three workers and causing a meltdown. The cause was a control rod that had been withdrawn incorrectly, but even after an investigation that took two years to complete, the actions taken by the workers just prior to the accident were never discovered.
Although the accident released radioactive material into the atmosphere, it was considered a small amount, and the reactor’s remote location helped to minimize damage to the neighboring population. Still, the incident is notable for being the only fatal nuclear reactor accident in US history, and for inspiring a change to the design of nuclear reactors, so that a mishap involving a single control rod would not do this kind of damage.
On January 21, 1968, a US Air Force B-52 bomber was running a “Chrome Dome” mission, a Cold War-era operation in which US bombers with nuclear payloads stayed in the air at all times, all with nearby targets in the Soviet Union that were to be attacked if commanded. The bomber, which was carrying four hydrogen bombs caught fire. The nearest emergency landing location was at Thule Air Base in Greenland, but there was not enough time to reach it, so the crew abandoned the bomber.
When it crashed, the nuclear payload ruptured and the area became contaminated with radiation. The March 2009 issue of Time magazine classified the event as one of the worst nuclear accidents of all time. The 1968 incident caused the immediate discontinuation of “Chrome Dome” missions, and more stable explosives were eventually developed so that nuclear weapons would be less likely to explode in an accident.
The Bohunice nuclear power plant was the first to be built in Czechoslovakia. The reactor was based on an experimental design that was meant to run on uranium mined in Czechoslovakia. However, the first-of-its-kind facility had multiple accidents, and it had to be shut down more than 30 times.
Two workers had been killed in a 1976 incident, but the worst mishap occurred on February 22, 1977 when a worker removed control rods incorrectly during a routine fuel change. This simple error caused a massive radioactive leak, and the ensuing accident earned a level 4 rating on the International Nuclear Event Scale of 1 to 7.
The Soviet government covered up the accident, so no reliable estimates of casualties have been released to the public. However, in 1979, the government decommissioned the plant, and it is expected to be fully dismantled in 2033.
Located one hour from Las Vegas, Yucca Flat is a desert basin that has served as one of Nevada’s nuclear test sites. On December 18, 1970, while detonating a 10 kiloton nuclear bomb buried 900 feet underground, the plug sealing the explosion from the surface cracked, sending a plume of radioactive fallout into the air and contaminating 86 workers who were on the site.
Apart from the radiation that fell locally, radioactive particles were carried to northern Nevada, Idaho, northern California and the eastern portions of both Washington and Oregon states. Radioactive material is also believed to have been carried into the Atlantic Ocean, Canada and the Gulf of Mexico. Two Nevada Test Site workers who had been present at the time died of leukemia in 1974.