International Nuclear Safety Group the Kyshtym disaster, which occurred at Mayak, a Nuclear fuel reprocessing plant in the Soviet Union. Since then, there have been hundreds of nuclear accidents, some considered minor while others were horrendous, with one of the worst accidents being the Chernobyl disaster of April 26, 1986. Involving a nuclear power plant at Chernobyl, now in Ukraine, a combination of nuclear volatility and the disregard of several safety procedures caused an explosion of its fourth reactor, ending in the worldwide environmental and human catastrophe. Following the Chernobyl accident, the IAEA was forced to create a new branch of their organisation to
Peaceful nuclear explosion many of the "tests" were considered economic applications, not tests, in the Nuclear Explosions for the National Economy program. These included one 30 kiloton explosion being used to close the Uzbekistani "Urtabulak" gas well in 1966 that had been blowing since 1963, and a few months later a 47 kiloton explosive was used to seal a higher pressure blowout at the nearby "Pamuk" gas field. (For more details, see Blowout (well drilling)#Use of nuclear explosions.) The public records for devices that produced the highest proportion of their yield via fusion-only reactions are possibly the Taiga Soviet peaceful nuclear explosions of