Power Generation: The World Nuclear Fleet Provides the world's electricity supply

According to the International Atomic Energy Agency, there are 444 "operating" nuclear reactors in 32 countries (as of September 27, 2021). Nearly 70% of these are pressurized light water reactors (PWRs), such as those installed in France. In 2020, the world's nuclear fleet generated 2,553 TWh, or 10.2% of all electricity produced in the world that year. The largest producers are the US (93 nuclear reactors) and France (56 reactors).

Reactors in operation

As of September 27, 2021, the total electrical capacity of the world's nuclear power plants was nearly 395 GW. More than half of this capacity is distributed among three countries: the United States, France, and China.

Despite having the largest number of nuclear reactors, the United States had only 19.7% of the country's share of nuclear-generated electricity in 2020. France is the country with the highest share of nuclear electricity: 67.1% in 2020, according to the RTE electricity balance.

There are six types of nuclear reactors in use worldwide

• Pressurized water reactors (PWR);
• Pressurized Heavy Water Reactors (PHWR);
• Boiling Water Reactors (BWR);
• Fast Breeder Reactors (FBR);
• Gas light water reactors (GCRs);
• Light Water Graphite Cooled Reactors (LWGR).

Reactors under construction

As of September 27, 2021, 51 reactors with a total capacity of about 54 GW were under construction in 19 countries. The largest number of reactors under construction is in China (14). Finland and France, with one reactor under construction each, are the other two countries that are building an EPR, a third-generation reactor. The most developed reactor type is still the VVER-type reactor, with a total of 43 units under construction.

Reactors shut down permanently

As of September 27, 2021, the IAEA has recorded the permanent shutdown of 194 reactors in 20 countries since 1963 (the date of the first permanent reactor shutdown). The shutdown reactors are mainly PWRs (61 units), PWRs (53 reactors) and SCRs (38 units) that are to be dismantled. Some are experimental, such as the small Phénix breeder reactor at the Marcoule site (shut down in February 2010), or prototypes, like the Superphénix reactor (shut down in late 1998).

How the world's nuclear fleet is controlled

Created in July 1957 at the initiative of US President Eisenhower, the International Atomic Energy Agency (IAEA) is dedicated to promoting "atoms in the service of peace." Today 173 countries are members of this UN organization.

The main areas of the IAEA's activities are:

• Nuclear safety and security;
• Safeguards and verification of nuclear activities and facilities;
• Promotion of the peaceful uses of nuclear science and technology.

Among the countries with the largest number of reactors:

• Canada - Canadian Nuclear Safety Commission (CNSC);
• China - National Nuclear Safety Administration (NNSA);
• South Korea - Korea Institute for Nuclear Safety (KINS);
• United States - Nuclear Regulatory Commission (NRC);
• France - Agency for Nuclear Safety (ASN);
• India - Atomic Energy Regulatory Board (AERB);
• Japan - Nuclear Regulation Authority (NRA);
• UK - Office for Nuclear Regulation (ONR);
• Russia - Federal Service for Environmental Industrial and Nuclear Supervision (ROSTEKHNADZOR).

Past and Present

Nuclear energy was first used to generate electricity on December 20, 1951. The U.S. pioneered (in Arches, Idaho) the EBR-I experimental reactor. This reactor provided four light bulbs and confirmed the concept of a nuclear generator. In 1954, a nuclear power plant connected to the electrical grid for the first time.

Less than three years later, on June 26, 1954, the world's first nuclear power plant, NPP-1, was connected to the electrical grid for the first time in Obninsk, Russia. This plant, with an electrical capacity of 5 megawatts (MW), was the first to produce nuclear electricity for commercial use.

Since a nuclear power plant was first connected to the grid in 1954, global nuclear capacity has grown almost continuously. This growth was significant between 1970 and 1990 (nuclear reactor construction peaked in the 1980s). In 1970, installed electrical capacity was about 20 GW, and in 1990 it grew to 300 GW, a fifteenfold increase. Today, Western Europe and North America remain the main producers of nuclear-generated electricity, ahead of Asia, Central and Eastern Europe.

Today, global nuclear capacity is growing again, albeit at a slower rate. This growth is mainly due to the construction of reactors in developing countries (China, India, etc.).

What the future holds for the world's nuclear power plants

The IAEA estimates that by 2050, global electricity production as a whole is expected to double. According to the Agency's "high" scenario, nuclear power could account for 12% of the world's energy mix in 2050 (and only 6% in the "low" scenario), compared to about 10.2% in 2020.