Civil construction of the main nuclear island structure has been completed at unit 3 of China’s Haiyang NPP in Shandong province, marked by the concreting of the containment water tank. China National Nuclear Corporation (CNCC) said its subsidiary, CNNC 24, had completed concrete pouring of the inner and outer ring walls and top plate of the CB20 module, “laying a solid foundation for the subsequent containment sealing test and hot functional test”.
The containment water tank – the final module – was hoisted into place on top of the containment building roof at Haiyang 3 in August. The hoisting of the 419-tonne module, measuring 26 metres in diameter, 10 metres in height, took one hour and 52 minutes.
The tank is part of the passive safety system which requires no operator actions to mitigate potential emergency situations, using natural forces such as gravity, natural circulation and compressed gas to achieve their safety function. The CB-20 module, in conjunction with other passive safety systems, can maintain unit safety for 72 hours without human intervention. It will store more than 3,000 tonnes of water, which can be used to help cool the reactor in an emergency. The water can also be directed into the reactor’s used fuel pool, while the tank can be refilled from water stored elsewhere on site.
The Haiyang NPP hosts two AP1000 reactors (units 1&2), which began commercial operation in 2018 and 2019, some two years behind schedule. Two CAP1000 reactors – the Chinese version of the Westinghouse AP1000 – are under construction (units 3&4). Construction of units 5&6, with CAP1000 reactors received official approval in April.
Construction of Haiyang 4 began in April 2023 and first concrete was poured for the nuclear island of Haiyang 3 in July 2022. This marked the official start of construction of the first of two CAP1000 pressurised water reactors planned as Phase II at the site. The planned construction period is 56 months, with the two units scheduled to be fully operational in 2027.
