Nuclear power

From the discovery of the neutron by James Chadwick in England in 1932 to the nuclear weapons created by J. Robert Oppenheimer and his colleagues in the Manhattan Project (1942–45), many scientists contributed to the discovery of nuclear power and its uses. The first nuclear reactor was built by Enrico Fermi at the University of Chicago. Proving that a nuclear reaction could be initiated, controlled, and stopped, Fermi’s Chicago Pile-1 (CP-1)—the first human-created, self-sustaining nuclear reactor—went “critical” (producing a stable, self-sustaining chain reaction) on December 2, 1942. The reactor was used for research until it was decommissioned in 1953. [1] [2] [3]

The first major use of nuclear power was for the creation of the atomic (nuclear fission) bomb, which was exploded on July 16, 1945, on the desolate plains of the Alamogordo Bombing Range, located 210 miles (193 km) south of Albuquerque, New Mexico. The next two atomic bombs were used by the U.S. military during World War II, dropped on Hiroshima and Nagasaki, Japan, on August 6 and 9, 1945, respectively, effectively ending the war. Nuclear weapons have not been used since. [4] [29]

At the close of World War II, the United States and the Soviet Union entered what would be a decades-long Cold War that increased public unease with nuclear energy—mainly the fear that the Soviet Union would develop nuclear weapons and use them on the United States. On December 8, 1953, U.S. Pres. Dwight D. Eisenhower gave his “Atoms for Peace” speech at the United Nations General Assembly, in which he said:

The United States pledges before you—and therefore before the world—its determination to help solve the fearful atomic dilemma—to devote its entire heart and mind to find the way by which the miraculous inventiveness of man shall not be dedicated to his death, but consecrated to his life. [5] [6]

Click for more on atomic bombs and nuclear weapons.

After World War II, nuclear reactors were built for consumer power generation. The first reactor capable of significant electric power generation and the first to power a small town was in Idaho; it generated electricity for the nearby town of Arco for about two hours on July 17, 1955. Called BORAX-III (short for “Boiling Reactor Experiment”), it was used for experiments until 1956. [3] [4] [7] [8]

The world’s first reactor used for large-scale commercial power production was the Calder Hall A reactor in Cumbria, England. However, the nuclear plant was primarily intended for plutonium production for the United Kingdom’s nuclear weapons program. Providing power to residences, which it did from 1956 to 2003, was a secondary service. [3] [9]

In the United States enthusiasm over nuclear power as a domestic energy source was quelled by the Three Mile Island accident in 1979, during which its TMI-2 nuclear reactor had a partial meltdown. The other reactor, TMI-1, was taken offline for a few years after the accident but later continued power production until being decommissioned in 2019. The subsequent nuclear accidents in Chernobyl, Soviet Union (in what is now Ukraine), in 1986 and in Ōkuma, Fukushima, Japan, in 2011 further fueled concerns about the safety and reliability of nuclear energy. [10] [11] [12] [13]

However, the increasing urgency to slow climate change and the dramatic rise of artificial intelligence (AI) have reignited interest and, some say, the undeniable need for increased nuclear power production. For example, Constellation Energy, which owns the TMI-1 reactor at Three Mile Island, has partnered with Microsoft to restart TMI-1 to power the company’s AI data centers as soon as 2027. [11] [13] [14]

According to the International Atomic Energy Agency (IAEA), there were (as of late 2025) 417 active nuclear power reactors globally, with 23 others in suspended operation, and 62 under construction. The World Nuclear Association notes that nuclear power reactors generate electricity in 31 countries, providing about 9 percent of the world’s electricity. Overall, 14 countries derived at least 25 percent of their energy from nuclear power in 2024. France, which has 57 active nuclear reactors, relied on nuclear power for nearly 70 percent of the country’s electricity. Slovakia (with five reactors) relied on nuclear for almost 61 percent of electricity, whereas Hungary (with four active reactors) and Ukraine (15 reactors) used nuclear power for about 50 percent. [15] [16]

The United States has 54 nuclear power plants with 94 active nuclear power reactors that generated just more than 18 percent of the country’s power in 2024. The oldest operational commercial nuclear power reactor is Nine Mile Point Unit 1 in New York (it began production in December 1969) and the newest is Vogtle Unit 4 in Georgia (began production in April 2024). The U.S. Nuclear Regulatory Commission (NRC) licenses reactors for an initial operation period of 40 years. Extension licenses may be granted for a total of 80 operational years. [16] [17] [18]

Slideshow: Nuclear power plant disasters: Three Mile Island, Chernobyl, and Fukushima

Assessment quiz

Take our assessment quiz to test your knowledge of nuclear power and other alternative energy sources. Good luck!

1-minute survey

After reading this debate, take our quick survey to see how this information affected your opinion of this topic. We appreciate your feedback.

Discussion questions

1. Is nuclear power a good form of energy? Why or why not?
2. Should nuclear power be used to complement renewable energies? Explain your answer.
3. Compare nuclear power to wind, solar, and fossil fuel energies. Which would you choose to power a town and why?
4. What questions do you have after reading the debate above? Where might you find answers?
5. What was the most interesting thing you learned from this debate?
6. Consider how you felt about the issue before reading this article. After reading the pros and cons on this topic, has your thinking changed? How and why?. If your thoughts have not changed, explain how and why you better understand the other side of the debate.
7. Push for the position and policies you support by writing local officials, U.S. senators and representatives, or other people in a position to make the change you champion.