First European Nuclear Reaction

Date: December 25, 1946 • Location: Khoroshëvo-Mnevniki, Russian Federation

The first European self-sustaining nuclear chain reaction is initiated within the Soviet Union's F-1 nuclear reactor.

In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series or "positive feedback loop" of these reactions. The specific nuclear reaction may be the fission of heavy isotopes. A nuclear chain reaction releases several million times more energy per reaction than any chemical reaction.