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 weapons and Ukraine by Russia. Ukraine would also have struggled with replacing the nuclear weapons once their service life expired, as Ukraine did not have a nuclear weapons program. In exchange for giving up its nuclear weapons, Ukraine received financial compensation, as well as the security guarantees of the Budapest Memorandum. On December 5, 1994 the leaders of Ukraine, Russia, Britain and the United States signed a memorandum to provide Ukraine with security assurances in connection with its accession to the NPT as a non-nuclear weapon state. The four parties signed the memorandum, containing a preamble and six paragraphs. The memorandum reads as