The Fukushima No.1 nuclear power plant in northeast Japan started to leak radioactive material after an hydrogen explosion, which was caused by a devastating earthquake and ensuring tsunamis, occurred Saturday afternoon.

The following are major nuclear accidents around the world since the former Soviet Union set up the world's first nuclear power plant in 1954:

On Oct. 10, 1957, a fire broke out at the Windscale nuclear reactor (later renamed Sellafield) in northwest England, destroying the core and releasing a cloud of radioactive material. The sale of milk and other produces from nearby farms were banned for a month. Scores of people later developed cancer and died because of exposure to radiation.

On March 28, 1979, a partial core meltdown occurred at Three Mile Island in the United States due to its cooling system failure, in the most severe nuclear leak accident in the country which forced the evacuation of at least 150,000 local residents.

On April 26, 1986, the No.4 reactor at the Chernobyl nuclear plant in the former Soviet Union exploded, causing the worst nuclear disaster in history. The explosion killed 30 people on the spot, released more than eight tons of highly radioactive material, contaminated 60,000 square km of land, and caused more than 3.2 million people to be affected by radiation.

On April 6, 1993, a tank containing radioactive liquid exploded at the Tomsk-7 Reprocessing Complex in the Siberian region of Russia. A total of 10 square km of land was contaminated by radioactive material and a number of nearby villages were evacuated.

On Sept. 30, 1999, a nuclear accident occurred at a nuclear fuel plant at Tokai village, Ibaraki prefecture, Japan, killing two workers, exposing dozens of people to radiation and forcing the evacuation of local residents.

On Aug. 9, 2004, four workers were killed and seven others injured by a steam leak at the No.3 reactor at Kansai Electric's Mihama power plant, 350 km west of Tokyo, Japan.