Which scientist developed the first nuclear chain reaction?

Which scientist developed the first nuclear chain reaction? Enrico Fermi developed and led the work that produced the first human-made, self-sustaining nuclear chain reaction.

Fermi directed the construction of Chicago Pile-1, the first artificial nuclear reactor, at the University of Chicago. The reactor used uranium and graphite: uranium fission supplied neutrons, while graphite slowed those neutrons so they could trigger further fissions. The carefully controlled multiplication of neutrons allowed the reaction to sustain itself.

Chicago Pile-1 went critical on 2 December 1942. This achievement demonstrated that a controlled nuclear chain reaction was possible and became a foundation for later reactor development and the Manhattan Project. Fermi’s team included scientists such as Leo Szilard, who had earlier conceived the possibility of a chain reaction and helped develop the reactor design.

The wording can cause a historical mix-up. Robert Oppenheimer later directed the Los Alamos laboratory, and Niels Bohr made major contributions to nuclear theory, but neither led the first self-sustaining chain reaction. Fermi received the 1938 Nobel Prize in Physics for work involving artificial radioactive elements and slow neutrons.