First concrete pouring has begun for the nuclear island of Unit 4 at the Sanao nuclear power station in eastern Chinese province of Zhejiang, project owner China General Nuclear (CGN) announced on Tuesday (10 November).
The company said the pouring of first concrete began at 08:28 local time on 10 November, marking the official start of main construction.
It said the total volume of concrete poured as of 10 November was approximately 8,820 cubic metres and the process is expected to last 60 hours.
The nuclear island is one of two primary zones of a nuclear power station. It houses the reactor core and safety systems.
Pouring of first concrete for the nuclear island represents the baseline event used by international regulators and industry databases to track a reactor’s official construction start date and schedule.
Sanao-4 is part of the second phase of the Sanao nuclear power project. The first phase of the project was the construction of Units 1 and 2. Phase three will see the construction of Units 5 and 6.
Sanao-1 began commercial operation at the site earlier this year while fuel loading was completed at Sanao-2 earlier this month. Construction of Unit 3 began in November 2025.
When all six units are operating Sanao is expected to produce 52.5 TWh of energy per year and will supply the larger Yangtze River Delta region.
All six units will be indigenous Hualong One pressurised water reactor units that incorporate elements of China National Nuclear Corporation’s ACP1000 and CGN’s ACPR1000+ reactor designs. The Hualong One is also known as the HPR1000.
According to the International Atomic Energy Agency, China has 60 nuclear units in commercial operation and 37 under construction. About half of those under construction are of the Hualong One design.
