On February 10, the primary circuit hydrostatic test (cold test) of Unit 3 at China National Nuclear Corporation (CNNC)'s Sanmen Nuclear Power Plant was successfully completed. The milestone marks a key turning point in the commissioning process of the unit, paving the way for its upcoming hot functional test, fuel loading, and startup.

The cold test serves as a comprehensive integrity check of the reactor coolant system — the plant's "artery" — by verifying the pressure boundary of the primary circuit. Through close coordination and dedicated efforts, the team ensured the test was completed successfully on the first attempt.

The Sanmen project plans to build six million-kilowatt-class nuclear power units. Once Phase II's Units 3 and 4 are commissioned, the plant's annual power generation will exceed 40 billion kWh, reducing carbon dioxide emissions by approximately 30 million tons per year and contributing significantly to regional energy optimization and power supply security.