At 12:50 PM on September 6, the cold functional test of Unit 4 at the Huaneng Hainan Changjiang Nuclear Power Phase II project reached its completion. During the test, the unit's pressure boundary remained fully intact, system tightness performed exceptionally well, and all test parameters met required standards.

The successful cold test marks Unit 4's official transition into the commissioning phase, laying a solid foundation for the unit's future high-quality grid connection and power generation. The cold test, essentially a hydrostatic pressure test of the nuclear island's primary loop, serves as one of the key milestones in nuclear engineering construction, with its core purpose being to comprehensively verify the integrity and leak-tightness of pressure boundaries—including primary loop pipe welds, equipment, and high-pressure sections of connected systems—thereby ensuring safe and stable operation in subsequent phases.

As a cornerstone energy project supporting the accelerated development of Hainan's free trade port with Chinese characteristics, the Huaneng Hainan Changjiang Nuclear Power Phase II project will significantly boost the region's energy supply capacity and raise the share of clean energy upon completion. The project adopts China's self-developed Hualong One reactor technology, comprising two pressurized water reactor units with a single-unit capacity of 1.2 million kilowatts. Once operational, the project will deliver 18 billion kilowatt-hours of clean electricity annually, equivalent to reducing standard coal consumption by 6.326 million tonnes and cutting carbon dioxide emissions by 11.68 million tonnes each year.