Wedoany.com Report-Oct. 22, The civil construction of the main nuclear island for unit 3 at the Haiyang nuclear power plant in Shandong province has been completed with the concreting of the containment water tank, CNNC 24, a subsidiary of China National Nuclear Corporation (CNNC), announced on October 20. The work included pouring concrete for the inner and outer ring walls and the top plate of the CB-20 module, "laying a solid foundation for the subsequent containment sealing test and hot functional test."

The containment water tank, the final module of the nuclear island, was hoisted onto the containment building roof on August 4. Measuring 26 meters in diameter, 10 meters in height, and weighing approximately 419 tonnes, the hoisting process was completed in one hour and 52 minutes. The CB-20 module will hold over 3,000 tonnes of water, which can be used to cool the reactor during emergencies or directed to the reactor's used fuel pool. The tank can also be refilled from other water storage on site.

The module is a key component of the plant’s passive safety systems, which operate without human intervention using natural forces such as gravity, natural circulation, and compressed gas. Alongside other passive safety features, the CB-20 can maintain unit safety for up to 72 hours without operator actions, providing an added layer of reliability.

China’s State Council approved the construction of two CAP1000 reactors — the domestic version of the Westinghouse AP1000 — at the Haiyang, Sanmen, and Lufeng nuclear sites on April 20, 2022. Approvals covered Haiyang units 3 and 4, Sanmen units 3 and 4, and Lufeng units 5 and 6. The Sanmen and Haiyang sites already host two AP1000 units each. Haiyang unit 1 began commercial operation in October 2018, followed by unit 2 in January 2019.

Construction milestones for Haiyang unit 3 began with the first safety-related concrete pour in July 2022. In March, the outer steel dome of the containment building was hoisted into place. Construction of Haiyang unit 4 started in April 2024. The planned construction timeline for both units is 56 months, with full commercial operation expected in 2027.

The completion of the CB-20 module marks a major step in the project, ensuring the structural integrity and safety of the reactor. With passive safety systems and robust containment measures in place, Haiyang unit 3 is on track to strengthen China’s nuclear capacity while adhering to high safety standards. The project reflects continued progress in the deployment of CAP1000 technology across the country, contributing to long-term energy security and the development of advanced nuclear infrastructure.