The following nuclear reactor accidents have occurred: 1957, Windscale, UK; 1965, Idaho Falls ID, USA; 1966, Detroit MI, USA; 1969, Saint-Laurent, France; 1975, Brown's Ferry AL, USA; 1979, Three Mile Island PA, USA; 1982, Kozluduj, Bulgaria; 1983, Constituyentes, Argentine; 1984; Greifswald, Germany; 1986, Gore, OK, USA; 1986, Chernobyl, Russia. According to the International Atomic Energy Agency (IAEA) more than 250 nuclear reactor accidents have been kept secret. The costs of such accidents are very high - the Three Mile Island accident was estimated to cost $500 million to clean-up, plus the costs to those inhabitants who lived nearby and left the area either permanently or for a short time, which amounted to $19 million. Nuclear explosion at Chernobyl caused evacuation of 135,000 people, death of 31 workers and immediate fall-out and the poisoning of agricultural land in the Soviet Union and Europe from relatively long-lived radioactive isotopes. The number of fatal cancers that might develop worldwide as a result of the accident could range from zero to 17,400, among local population between 5,000 and 25,000.
In 1991, there were 165 incidents with nuclear reactors in Russia. Fifty-eight incidents involved the Chernobyl RMBK reactor, but twice as many reported incidents involved VVK reactors, which are supposedly of a safer design. Of the 165 incidents, only 37 were regarded as insignificant. There were two serious radiation leaks.