Following an earthquake, tsunami, and failure of cooling systems at Fukushima Daiichi Nuclear Power Plant in Japan on March 11, 2011, a nuclear emergency was declared. This was the first time a nuclear emergency had been declared in Japan, and 140,000 residents within 20 km of the plant were moved out. Explosions and a fire resulted in dangerous levels of radiation, resulting in a stock market collapse and panic-buying in supermarkets. As of April 2011, water is still being poured into the damaged reactors to cool melting fuel rods. John Price, a former member of the Safety Policy Unit at the UK's National Nuclear Corporation, has said that it "might be 100 years before melting fuel rods can be safely removed from Japan's Fukushima nuclear plant". Following the Fukushima nuclear disaster, the International Energy Agency halved its estimate of additional nuclear generating capacity to be built by 2035.
Kashiwazaki-Kariwa Nuclear Power Plant, the largest nuclear generating station in the world by net electric power rating, happened to be near the epicenter of the strongest Mw 6.6 July 2007 Chūetsu offshore earthquake. This initiated an extended shutdown for structural inspection which indicated that a greater earthquake-proofing was needed before operation could be resumed. On May 9, 2009, one unit (Unit 7) was restarted, after the seismic upgrades. The test run had to continue for 50 days. The plant had been completely shut down for almost 22 months following the earthquake.
Tomsk-7 explosion, April 6. 1993: The accident in the Siberian city of Tomsk took place after a tank exploded while being cleaned. The explosion released a cloud of radioactive gas drifting from the Tomsk-7 Reprocessing Complex.
Goiania accident, September 13, 1987: More than 240 people were exposed to radiation when a junkyard dealer in Goiania, Brazil, broke open an abandoned radiation therapy machine and removed a small highly radioactive pieces from there. Children, attracted to the bright blue of the radioactive material, touched it and rubbed it on their skin, resulting in the contamination of several city blocks which had to be demolished.
Chornobyl disaster, April 26, 1986: On the morning of April 26, 1986, reactor number four at the Chornobyl Nuclear Power Plant exploded. More explosions followed, and the resultant fires sent radioactive fallout into the air. Four hundred times more fallout was released than that at the atomic bombing of Hiroshima. The Chornobyl disaster is considered to be the worst nuclear power plant disaster in history.
Chornobyl Nuclear Power Plant reactor number 4, the enclosing sarcophagus and the memorial monument, 2009.
K-431 Chazhma Bay, August 10. 1985: During refuelling in Vladivostok, Russia, this Echo II class submarine suffered an explosion, sending a radioactive cloud of gas into the air. Ten sailors were killed in the incident and 49 people suffered radiation injuries.
Three Mile Island accident, March 28, 1979: The partial meltdown of the Three Mile Island Unit 2 nuclear power plant was the most serious nuclear power plant accident in the U.S., despite the fact that it led to no deaths or injuries.
Yucca Flat, December 18. 1970: After a nuclear test involving the detonation of a 10 kiloton nuclear device underneath Yucca Flat in Nevada, the plug sealing the shaft from the surface failed and radioactive material was released into the atmosphere. Eighty six workers at the site were exposed to radiation.
Thule accident, Janury 21, 1968: A cabin fire aboard a B-52 forced the crew of the American bomber to abandon the craft before it could land. The bomber crashed onto sea ice near the Thule Air Base in Greenland, causing the nuclear payload to rupture, which resulted in widespread radioactive contamination.
Palomares incident, January 17, 1966: A U.S. B52 bomber collided with KC-135 tanker during mid-air flight refuelling over the coast of Spain. The tanker was completely destroyed in the accident, while the B52 broke apart, releasing four hydrogen bombs. The non-nuclear weapons in two of the bombs detonated on impact with the ground, contaminating of a 490 acre area with radioactive plutonium.
Windscale fire, October 10, 1957: The accident occurred near Cumberland when the graphite core of a British nuclear reactor caught fire. The fire resulted in a release of much radioactive contamination.