Energy · 1942
Nuclear reactor
Chicago Pile-1 achieves the first self-sustaining chain reaction.
Enrico Fermi's team brought a graphite-and-uranium pile under Stagg Field to criticality on 2 December 1942. Controlled chain reactions made plutonium production, naval propulsion and nuclear electricity possible.
What it built on 2
What it led to 7
Watch
Related measurements
The dashed line marks when it first worked.
Nuclear electricity generation Latest: 2.81k TWh (2025) Source: Our World in Data
Share of electricity from low-carbon sources Latest: 42.6 % (2025) Source: Our World in Data
World energy per person by source since 1800 Latest: 20.1k kWh per person (2025) Source: Our World in Data