The concreting of the outer dome of the containment building has been completed at unit 3 of China’s Changjiang NPP in Hainan province. China National Nuclear Corporation (CNNC) said this marks the completion of the main structure of the reactor building of the nuclear island and “entry of the project construction into a new stage, laying a solid foundation for the full launch of subsequent nuclear island hot testing and commissioning”.
Changjiang 3&4, both with Hualong One reactors, are planned to be fully operational in early 2027. First concrete was poured for the base slab of unit 3’s nuclear island in March 2021, and for unit 4 the following May. Changjiang Phase II (units 3&4) involved estimated investment of CNY40bn ($6.4bn), according to China Huaneng, which holds a 51% share in the project. China National Nuclear Corporation holds the remaining 49%. The construction period is expected to be 60 months. The site is already home to two operating CNP-600 pressurised water reactors (PWRs) – Changjiang 1&2 – which entered commercial operation in 2015 and 2016. In 2021, CNNC also began construction of a demonstration ACP100 small modular reactor (Linglong One) at the site.
The Hualong One reactor design features a double-layered containment building, the main function of which is to ensure the integrity and leak tightness of the reactor building, and it plays a key role in the containment of radioactive substances.
The steel dome for Changjiang 3’s inner containment – measuring more than 46 metres in diameter and 23 metres in height – was placed on top of the walls of the double containment structure in February 2023. Then in October 2024, the outer steel dome – measuring 53 metres in diameter, 13 metres in height and weighing about 415 tonnes – was hoisted into place on top of the containment building in October last year.
Cold hydrostatic testing – carried out to confirm whether components and systems important to safety are properly installed and ready to operate in a cold condition – were completed in April. These will now be followed by hot functional tests, which involve increasing the temperature of the reactor coolant system and carrying out comprehensive tests to ensure that coolant circuits and safety systems are operating as they should.
