В 1946 г. в СССР впервые осуществили  цепную ядерную реакцию

The event that happened at the Atomic Energy Institute, specifically at Testing Lab 2 of the Academy of Sciences of the USSR, was movie-like: at 6 p.m. after the war in 1946. That day with the personal involvement of Igor V. Kurchatov the first nuclear chain reaction in the USSR was conducted on the IGR reactor. “Now nuclear energy has succumbed to the will of a Soviet person,” said the father of the prospective Soviet nuclear bomb.

Nuclear energy had succumbed to the will of a US person 4 years before that, but science has no borders.