Lake Chagan (Kazakh: Шаған, Shaǵan), or Lake Balapan, is a lake in Kazakhstan created by the Chagan nuclear test on January 15, 1965, which was conducted as part of the Soviet Union's Nuclear Explosions for the National Economy program. A 140 kiloton device was placed in a 178-metre-deep (584 ft) hole in the dry bed of the Chagan River. The blast created a crater 400 m (1,300 ft) across and 100 m (330 ft) deep with a lip height of 20 to 38 m (66 to 125 ft); it is often referred to as "Atomic Lake".