Countries With the Most Nuclear Reactors: Ranked

The United States has the most nuclear reactors of any country, operating more than 90 reactors. France runs about 56 reactors and produces the highest share of its electricity from nuclear power, roughly 65 to 70 percent. China leads the world in reactors under construction, followed by Russia, South Korea, Japan, India, and Canada.

Introduction

Nuclear power supplies about 10 percent of the world's electricity from roughly 440 operable reactors spread across some 30 countries. But the raw number of reactors a country operates tells only part of the story. A nation can have many reactors yet still draw most of its power from coal or gas, while another may run fewer reactors but rely on them for the bulk of its grid.

This guide ranks the leading nuclear nations by reactor count and explains the crucial difference between the number of reactors and the share of electricity those reactors actually provide. The two metrics produce very different leaders: the United States for scale, France for dependence.

Countries With the Most Nuclear Reactors

The Leading Nuclear Nations

• United States: More than 90 operable reactors, the largest fleet in the world. Nuclear supplies roughly 18 to 20 percent of American electricity, more total nuclear generation than any other country despite that modest share.
• France: About 56 reactors. France gets the highest share of its electricity from nuclear power of any nation, roughly 65 to 70 percent, the result of a deliberate national program launched after the 1970s oil crises.
• China: Around 55 to 57 operable reactors and rising fast. China leads the world in reactors under construction, adding new capacity more quickly than any other country as it expands its low-carbon grid.
• Russia: Roughly 36 reactors, supplying about 20 percent of the country's electricity. Russia is also a major exporter of reactor technology, building plants abroad through its state nuclear firm.
• South Korea: Around 26 reactors that provide close to 30 percent of national electricity. South Korea is a leading reactor builder and exporter, having constructed plants in the United Arab Emirates.
• Japan: About 33 operable reactors, though many were idled after the 2011 Fukushima accident and only a portion have since restarted. Nuclear once supplied around 30 percent of Japanese power.
• India: Roughly 20 to 24 reactors, with an ambitious expansion program. Nuclear currently supplies only about 3 percent of India's electricity, but the country is building more capacity.
• Canada: Around 19 reactors, most located in Ontario, where nuclear supplies more than half of provincial electricity using homegrown CANDU heavy-water technology.

The United States built most of its fleet in the 1970s and 1980s, and although few new plants have opened since, uprates and high reliability keep American reactors generating enormous amounts of power. France stands apart because it made a national decision to go nuclear, giving it the cleanest large grid in the industrialized world.

China is the story of the future. While its current reactor count sits just behind the United States and France, it has the most units under construction anywhere on Earth and is on track to overtake both leaders within the coming decades.

Reactor Count Versus Share of Electricity

• Most reactors: United States, with over 90 operable units.
• Highest nuclear share: France, at roughly 65 to 70 percent of electricity.
• Most under construction: China, expanding faster than any other nation.
• Other high-share countries: Slovakia, Ukraine, and Hungary all draw around half or more of their power from nuclear.

These two measures rarely point to the same country. The United States has the biggest fleet but relies on nuclear for less than a fifth of its power because its grid is so large and diverse. France, with far fewer reactors, depends on them for most of its electricity. Understanding this distinction is essential to reading any nuclear ranking correctly.

Common Questions

Which country has the most nuclear reactors?

The United States has the most, operating more than 90 commercial reactors. That is the largest nuclear fleet in the world and produces more total nuclear electricity than any other nation, even though nuclear supplies less than 20 percent of American power.

Which country gets the largest share of its electricity from nuclear power?

France leads by share, generating roughly 65 to 70 percent of its electricity from nuclear reactors. This is the highest proportion of any country and stems from a national program begun in the 1970s to reduce dependence on imported oil.

Which country is building the most nuclear reactors?

China is building more reactors than any other country. It has the largest number of units under construction worldwide and is expected to surpass both France and the United States in total reactor count over the coming decades.