Unit 7 of the Tianwan Nuclear Power Plant in East China’s Jiangsu Province, developed by China National Nuclear Corporation (CNNC), has completed cold functional testing on July 23, 2025. Photo: courtesy of CNNC
The Tianwan Nuclear Power Plant’s Unit-7 reactor, in East China’s Jiangsu Province, developed by China National Nuclear Corporation (CNNC), completed cold functional testing on Wednesday, marking its full transition from the construction phase to commissioning phase. The milestone sets the basis for the safe and orderly commissioning of subsequent units, according to a statement CNNC sent to the Global Times.
As a major integrated commissioning test for nuclear power plants, the cold functional test serves as the first comprehensive check of reactor performance. It verifies the integrity and functionality of the systems, equipment, and auxiliary pipelines under high pressure, ensuring safe and stable operation in subsequent stages, per the statement.
Since breaking ground in May 2021, the Unit 7 of the Tianwan Nuclear Power Plant has hit several key milestones—including dome installation, main pipeline welding, and cold testing—with a focus on quality and efficiency. Upcoming phases include pressure testing, hot trials, fuel loading, and grid connection, per the statement.
The Tianwan Nuclear Power Plant is designed to house eight reactor units. With Units 1 to 6 already in operation, the station has generated over 480 billion kilowatt-hours of electricity—equivalent to the annual consumption of 130 million households.
Lin Boqiang, director of the China Center for Energy Economics Research at Xiamen University, told the Global Times on Wednesday that China's nuclear power sector has played a prominent role in the nation's low-carbon industrial transformation.
"By integrating China's manufacturing capabilities with the latest Unit 7 reactor technology, the country's nuclear power industry is well positioned to drive sustainable energy transition," he said.
Units 7 and 8 are slated to begin commercial operation in 2026 and 2027. Once operational, Tianwan will have an installed capacity of 9 million kilowatts, delivering more than 70 billion kilowatt-hours of clean energy annually—enough to reduce China’s carbon footprint by an estimated 57.4 million tons each year.
Meanwhile, Tianwan has expanded beyond power generation into integrated nuclear energy use, supporting economic growth and decarbonization. CNNC’s “Heqi-1” steam supply project, now one year in operation, has delivered over 3.17 million tons of clean steam—saving 264,200 tons of coal and reducing carbon dioxide emissions by 706,600 tons.
"Infrastructure plays a leading role in China's economic growth. It's vital to speed up the construction to boost local economic development throughout the landscape of the country," Bian Yongzu, executive deputy editor-in-chief of Modernization of Management magazine, told the Global Times on Wednesday.
Bian noted that large infrastructure projects have boosted China's strength. "We have established standards and experience, allowing us to execute more projects quickly and efficiently, supporting regional development.”
According to data from the National Energy Administration, China’s total installed and under-construction nuclear power capacity has reached 125 million kilowatts, ranking first in the world.
China is the world’s largest clean energy market and plays a pivotal role in global clean energy development, a senior official from the China Council for the Promotion of International Trade (CCPIT) recently stated. In 2024, China’s investment in clean energy reached $625 billion—accounting for one-third of the global total—positioning the country as a stabilizing force in the global clean energy supply and industrial chains.
Editor:Evan
