Operable nuclear power reactors worldwide 2023, by country

As of May 2023, there were 436 nuclear reactors in operation in 32 countries around the world. The United States had the largest number of nuclear power reactors in operation at the time, at 93 units. Operable nuclear reactors are those connected to the grid.

Nuclear reactors under construction

The largest reactors under construction as of May 2023 were situated in the UK, with a gross electricity generation capacity of 1,720 megawatts. Meanwhile, the country with the largest capacity of nuclear reactors under construction worldwide was China, where reactors with a total capacity of almost 22 gigawatts were being built at the time.

History of nuclear energy generation

In 1954, history was made when nuclear fission technology was approved for commercial purposes and the first nuclear power plant started operation in the Russian city of Obninsk. The new energy proved to be an extremely reliable and stable form of electricity. Since nuclear power plants are only shut down for refueling about every two years, they provide an around-the-clock “baseload” supply of power.

In nuclear fission, uranium atoms are split into lighter elements. Uranium is a radioactive metal that is extracted from mines, mainly in Kazakhstan, Australia, and Namibia. After the uranium splitting process, the used fuel elements are still radioactive and have to be stored in nuclear waste repositories or spent fuel pools. These sites are often underground and require thick metal or concrete walls to shield the public from radiation.