Памяти ликвидаторов ЧАЭС Андрей Шурков www.shurkov.com The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986, at the Chernobyl Nuclear Power Plant in Ukraine then in the Ukrainian Soviet Socialist Republic, part of the Soviet Union. It is considered the worst nuclear power plant accident in history and is the only level 7 event on the International Nuclear Event Scale. dispersed large quantities of radioactive fuel and core materials into the atmosphere and ignited the combustible graphite moderator