Power Grid

A Chinese nuclear reactor has made headlines by setting a new national record for uninterrupted operation. The first unit of the third phase of the Qinshan Nuclear Power Plant successfully ran for 738 consecutive days before being shut down on May 1, 2025.

This achievement marks the longest continuous operation for any grid-connected nuclear reactor in China. Additionally, it broke the global record for continuous operation by a CANDU 6 reactor, a type of pressurized heavy water reactor originally developed in Canada.

While the new milestone is significant, the world record for the longest continuous operation by a nuclear reactor still belongs to Darlington Unit 1 in Canada, which ran for 1,106 days before being shut down in February 2021.

The Qinshan Nuclear Power Plant has played a crucial role in China’s nuclear energy development, earning the nickname “glory of the nation.” Since its first connection to the grid in 1991, the plant has expanded to include nine operating units and boasts an installed capacity exceeding 6.66 million kilowatts, making it a major hub for nuclear power in China.

The third phase of the plant includes two heavy water reactor units, built in cooperation with Atomic Energy of Canada Limited. The record-breaking unit began its latest operating cycle on April 24, 2023, generating more than 12.5 billion kilowatt-hours of electricity.

This output is estimated to have saved 3.8 million tonnes of coal and reduced carbon dioxide emissions by nearly 10 million tonnes. As the units near the end of their original 30-year lifespan, a major refurbishment project is underway to extend their service life by another three decades.

This performance underscores the reliability and efficiency of CANDU 6 reactors, which can be refueled while still in operation—a key factor in their extended run times. These reactors are currently in use in several countries, including Canada, Romania, Argentina, South Korea, and China.

Designed with a unique horizontal vessel called a “Calandria,” which houses 480 pressure tubes, CANDU reactors are known for their robust design and operational flexibility. The Qinshan plant’s recent achievements highlight both the strategic importance of nuclear energy in China and the enduring success of international collaboration in nuclear technology.