Madhumitha Jaganmohan
Research expert covering climate and environmental sustainability
Nuclear energy is based on the power derived from the process of nuclear fission. During fission, a neutron bombards a large uranium atom, which splits, releasing more neutrons that start a chain reaction as they collide with other atoms. The fission of uranium atoms releases energy that can heat water to extremely high temperatures, the steam of which is used to spin turbines connected to electricity generators. In 1954, the first nuclear power plant came online in the Russian city of Obninsk. Since then, global nuclear power capacity grew from just five megawatts to 390 gigawatts in the last decade.
The world's largest nuclear energy producers
As of May 2023, there were 436 nuclear power reactors in operation across 32 countries. Around 20 percent of them were in the United States, the largest nuclear power generating country in the world, followed by China, France, and Russia. At an over 60 percent share of nuclear in electricity generation output, France relies heavily on this energy source. Meanwhile, motivated by its low emission rate for electricity production, the share of nuclear energy in the Chinese electricity mix has more than doubled in the past decade, reaching five percent in 2021. In 2023, China had the largest number of nuclear reactor projects and was expected to become the largest nuclear power producer within 10 years.Nuclear energy policy: a global snapshot
After the 2011 nuclear disaster at Japan’s Fukushima Daiichi plant, concerns about the safety of nuclear plants regained the spotlight and one in four world countries producing nuclear power as of 2021 vowed to accelerate the shutdown of existing plants and stop investment in new facilities. The first country to put this plan into practice was Germany, which phased out nuclear energy in early 2023. Belgium, the Netherlands, Spain, Sweden, Switzerland, and Taiwan planned to emulate this country, but Belgium, the Netherlands, and Sweden reversed their nuclear policy following the global energy crisis in 2022. The global nuclear power capacity is expected to continue growing in coming years, especially in Asia, where most of the nuclear reactors under construction and planned as of 2023 were located.Uranium production and supply
Fuel supply remains essential for any country wishing to increase its nuclear power generation output. Uranium and plutonium are the most widely used nuclear fuels. Globally, roughly 49,000 metric tons of uranium were produced from mines in 2022, with Kazakhstan, Australia, and Namibia as the leading uranium producers. The Kazakh KazAtomProm is the largest uranium-producing company in the world, accounting for 25 percent of the global market in 2021. It was followed by multinationals Orano and Uranium One, headquartered in France and Canada, respectively.
