San’ao Unit 1 Begins Commercial Operation, First Hualong One in Yangtze Delta

San’ao Unit 1 has crossed the line that matters to lenders, grid planners and reactor vendors alike: commercial operation. The 1,116 MWe net domestically designed pressurised water reactor entered service at 11:18 on 29 April 2026 after completing a 168-hour test run, turning a long commissioning sequence into a live operating asset in Cangnan County, Wenzhou, Zhejiang province.

For China General Nuclear, the milestone is bigger than one unit. San’ao is the first Hualong One nuclear power project in the Yangtze River Delta, and Unit 1 is the first of six Hualong One reactors planned for the site. That makes the plant a benchmark for how quickly a standardized Chinese design can move from first concrete to grid connection, hot testing and finally commercial dispatch in one of the country’s most power-hungry regions.

The timeline is unusually clear. China’s State Council approved Units 1 and 2 in September 2020. The National Nuclear Safety Administration issued the construction permit on 30 December 2020, and first concrete for Unit 1 was poured the next day, 31 December 2020. Unit 1 then reached first criticality on 14 February 2026, connected to the grid at 17:28 on 12 March 2026, and reached commercial operation roughly five years and four months after the nuclear island’s first concrete.

That progression matters because the 168-hour test is the gate between a successful startup and bankable operation. Once a unit can hold steady through that full run, it is no longer just a commissioning story. It becomes a repeatable deployment story, one that can be used to measure delivery risk, schedule discipline and the maturity of the supply chain behind Hualong One.

San’ao also carries policy weight. CGN said the project’s first phase includes Units 1 and 2, with Geely Technology Group holding a 2 percent stake. It is the first nuclear power project in China to incorporate private capital, and its six-unit buildout is expected to generate more than 54 TWh a year while cutting more than 16 million tonnes of standard coal use and about 51 million tonnes of carbon dioxide annually.

CGN has also leaned on digital construction tools, including a smart construction site and an AI-based radiographic-film management system. With Units 3 and 4 approved in August 2024 and the full six-unit site still expanding, San’ao Unit 1 now serves as the operating reference point for the next wave of domestic Hualong One construction in China and for the reactor’s commercial pitch abroad.