The History of Nuclear Power
The effort to harness nuclear fission for electricity, from the first man-made reactor of 1942 through the growth of a global industry, the accidents and public opposition that shaped its regulation, and its renewed role in low-carbon energy policy.
Events
Chicago Pile-1 Achieves the First Chain Reaction
On December 2, 1942, a team led by Enrico Fermi achieved the world's first self-sustaining nuclear chain reaction in Chicago Pile-1, a reactor built under the stands of Stagg Field at the University of Chicago. The experiment, part of the Manhattan Project, proved that controlled fission was possible and laid the technical foundation for both nuclear weapons and, later, civilian power generation.
Location: Chicago, Illinois, USA
Atoms for Peace and the First Nuclear Electricity
On December 20, 1951, the Experimental Breeder Reactor I in Idaho became the first reactor to generate electricity from nuclear fission, lighting four bulbs. President Eisenhower's "Atoms for Peace" speech to the UN General Assembly in December 1953 promoted the peaceful use of nuclear energy, and the International Atomic Energy Agency was established in 1957 to promote and regulate the technology.
Location: Arco, Idaho, USA
Obninsk Connects to the Grid
The Obninsk Nuclear Power Plant in the Soviet Union, connected to the grid in June 1954, became the world's first nuclear power plant to deliver electricity to an external grid, at a capacity of 5 megawatts. Britain's Calder Hall, opened in 1956, became the first commercial-scale plant, and the U.S. Shippingport reactor in Pennsylvania, commissioned in 1957-1958, pioneered the pressurized light-water reactor design that would dominate the industry worldwide.
Location: Obninsk, Soviet Union
The Global Buildout of the 1960s and 1970s
Utilities in the United States, France, Japan, the Soviet Union, Britain, Canada and West Germany ordered hundreds of reactors through the late 1960s and 1970s, and global installed nuclear capacity grew to roughly 100 gigawatts by the late 1970s and about 300 gigawatts by 1990. France in particular built a fleet that came to supply the majority of its electricity. The oil crises of 1973 and 1979 gave nuclear power a stated rationale in energy security, while growing environmental and safety movements began organizing opposition to plant construction.
Three Mile Island Halts the American Buildout
On March 28, 1979, a cooling failure caused a partial meltdown of one reactor at Three Mile Island in Pennsylvania. No deaths or injuries resulted, and studies found negligible off-site health effects, but the evacuation of 144,000 people and confusion in official communication eroded public trust. No new U.S. plant ordered after 1974 was completed for decades; regulators tightened oversight and construction costs rose, while the anti-nuclear movement gained a symbolic focus.
Location: Dauphin County, Pennsylvania, USA
Chernobyl Deepens Public Opposition
The April 26, 1986 explosion and fire at the Chernobyl No. 4 reactor, the worst nuclear accident in history, contaminated large areas of Europe and forced the permanent evacuation of the surrounding region. The disaster hardened public opposition in Western Europe, contributing to referendum defeats for expansion in several countries and eventual phaseout laws in Italy, Sweden, and later Germany, even as France and Japan continued operating large fleets.
Location: Chernobyl, Ukrainian SSR, Soviet Union
Fukushima and the German Phaseout
After the March 11, 2011 earthquake and tsunami caused meltdowns at the Fukushima Daiichi plant in Japan, the German Bundestag voted in June 2011 to amend its Atomic Energy Act and shut down all German nuclear plants by 2022, closing eight reactors immediately. Japan shut down its entire fleet for inspection, with most plants remaining offline for years. Supporters of phaseout cited radiation risk and unresolved waste storage; critics noted that lost nuclear output raised electricity costs and, at times, coal and gas generation. Other countries, including France, China, Britain, and the United States, reaffirmed nuclear power as part of their energy mix.
Location: Berlin, Germany
Nuclear Power in Climate Policy
Nuclear plants supplied about 2,600 terawatt-hours of electricity in 2023, roughly 9 percent of global generation, making fission the second-largest low-carbon power source after hydroelectricity. At the COP28 climate summit in Dubai in December 2023, more than 20 countries pledged to work toward tripling global nuclear capacity by 2050, framing it as a complement to renewables; environmental groups remained divided, with some citing reactor economics and waste, and others pointing to studies finding nuclear among the safest and lowest-carbon sources per unit of energy. Debate over nuclear power's role in decarbonization continues.
Location: Dubai, UAE