The Chernobyl accident1 was a nuclear accident that occurred on April 26, 1986 at the Vladimir Ilyich Lenin nuclear power plant, located in northern Ukraine, which at that time belonged to the Union of Soviet Socialist Republics, 3 km from the city from Pripyat, 18 km from the city of Chernobyl and 17 km from the border with Belarus. It is considered the worst nuclear accident in history.