Containment dome installed at third Haiyang unit

Monday, 24 March 2025

The dome - measuring about 41 metres in diameter, 11 metres in height and weighing almost 1000 tonnes - was lifted into place on the containment walls using a 3200-tonne crawler crane on 23 March. The process took 2 hours and 12 minutes, State Power Investment Corporation subsidiary Shandong Nuclear Power Group announced.

The steel containment shell is an important part of the nuclear island reactor building and the third safety barrier to prevent the leakage of radioactive materials, the company noted.

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The dome's installation "marks the basic completion of the main structure of the nuclear island plant and lays the foundation for the subsequent installation of the iconic module of the third-generation nuclear power - the passive containment cooling water storage tank - on its upper part", the company said.

This storage tank will hold water to help cool the reactor in an emergency. The water can also be directed into the reactor's used fuel pool, while the tank itself can be refilled from water stored elsewhere on site. The tank is part of the plant's passive safety systems which require no operator actions to mitigate potential emergency situations, using natural forces such as gravity, natural circulation and compressed gas to achieve their safety function.

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The construction of two CAP1000 reactors - the Chinese version of the Westinghouse AP1000 - at each of the Haiyang, Sanmen and Lufeng nuclear power plant sites in China was approved by the country's State Council on 20 April 2022. The approvals were for Haiyang 3 and 4, Sanmen units 3 and 4 and units 5 and 6 of the Lufeng plant. The Sanmen and Haiyang plants are already home to two AP1000 units each.

Unit 1 of the Haiyang plant entered commercial operation in October 2018, with unit 2 following in January 2019. Together, Haiyang units 1 and 2 can provide some 20 TWh of electricity to the grid annually, sufficient to meet one-third of household demand in Shandong province.

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The first safety-related concrete was poured for the nuclear island of Haiyang unit 3 in July 2022. Construction of Haiyang 4 began in April last year. The planned construction period for Haiyang 3 and 4 was 56 months, with the two units scheduled to be fully operational in 2027.

"Once the project is fully completed, the four units of the Haiyang nuclear power plant will generate 40 billion kWh of electricity annually, which can meet the electricity needs of half of the residents in Shandong Province and provide more clean heat sources for the Jiaodong Peninsula," Shandong Nuclear Power Group said.