China's nuclear power push relies on large reactors

China's nuclear fleet has nearly doubled since 2016, reaching nearly 60 gigawatts of total power capacity. The new facilities are nearly all gigawatt-scale pressurized-water reactors. The US, on the other hand, has built just two reactors in that time—Unit 3 and Unit 4 at Plant Vogtle in Georgia.

While smaller reactors are attracting significant excitement and investment, China is pressing on with large reactors. The world is racing to meet rising electricity demand, and many countries are interested in energy sources like nuclear power that don’t come with greenhouse-gas emissions. The key question is which of these strategies will really pay off in terms of getting electrons on the grid quickly.

Today, the US and France are known as leaders in the nuclear industry, with the US having the world’s largest fleet and France coming in second. France is heavily dependent on nuclear for its grid, with about two-thirds of the country’s power coming from nuclear reactors. However, both countries have hardly added any new reactors to their fleets in recent years.

Building large nuclear reactors is incredibly difficult, with up-front investment running into the billions and designs often changing during the regulatory process, adding cost and time. Many hope that smaller reactors could be the key to turning things around in these countries. The idea behind smaller reactors is that shrinking the footprint cuts down the initial investment needed.

These reactors could even be built in a factory rather than on-site, allowing for a lower price over time. The US Department of Energy has set a goal of having three test reactors reach criticality by July 4, 2026. California-based Antares hit the milestone with its Mark-0 reactor last week.

Antares plans to eventually build microreactors designed to produce between 100 kilowatts and 1 megawatt of electricity. The company plans to produce electricity in late 2027 and deploy in the field by 2028, according to CEO Jordan Bramble. Meanwhile, China is churning out large nuclear reactors at a stunning pace.

Construction started on six new reactors there in 2025, and two more got underway in the first five months of 2026. The country is on course to overtake both the US and the European Union in installed nuclear capacity by 2030. The speed of construction in China is staggering, with an average time to build a new reactor of between five and seven years, compared to the global average of about nine years and 15 years for the two most recent reactors in the US.

Standardization is a key factor, with China using a uniform project management system to design, license, and build new reactors. Larger reactors generally provide more electricity to the grid for a lower price, a key consideration in view of China’s steeply increasing electricity demand. While smaller reactors require less up-front investment, they’ll actually be more expensive per unit of electricity produced.