Ukraine ousted Khrushchev and became the Soviet leader from 1964 to 1982. Many prominent Soviet sports players, scientists, and artists came from Ukraine. On 26 April 1986, a reactor in the Chernobyl Nuclear Power Plant exploded, resulting in the Chernobyl disaster, the worst nuclear reactor accident in history. This was the only accident to receive the highest possible rating of 7 by the International Nuclear Event Scale, indicating a "major accident", until the Fukushima Daiichi nuclear disaster in March 2011. At the time of the accident, 7 million people lived in the contaminated territories, including 2.2 million in Ukraine. After the
Nuclear explosion (those few nations with capability) has detonated roughly 1,700 nuclear explosions, all but 6 as tests. Of these, six were peaceful nuclear explosions. Nuclear tests are experiments carried out to determine the effectiveness, yield and explosive capability of nuclear weapons. Throughout the 20th century, most nations that have developed nuclear weapons had a staged test of them. Testing nuclear weapons can yield information about how the weapons work, as well as how the weapons behave under various conditions and how structures behave when subjected to a nuclear explosion. Additionally, nuclear testing has often been used as an indicator of scientific