The inner dome of the containment building has been installed at the unit 3 of the Changjiang NPP in China’s Hainan province. China National Nuclear Corporation (CNNC) said the steel dome with a diameter of 46.8 metres, a height of 23.4 metres and weighing 518 tons was hoisted to a height of some 70 metres and lowered into place at an altitude of about 45 metres using a 3200-tonne crawler crane. Changjiang 3&4, both with Hualong One reactors, are planned to be fully operational in early 2027. CNNC said this signalled transition from the civil engineering stage of construction to the installation stage.
China Huaneng, which owns 51% of the project’s shares, noted that work platforms and individual suspended cells were used to assemble the internal dome of Changjiang 3, which marks a change from the traditional way of constructing scaffolding, "creating a precedent in the industry with zero scaffolding to complete the assembly of domes with steel cladding and the construction of mounting elements".
The inner dome was suspended using 16 hanger points to connect a wire rope which is connected to a hook through a circular transition beam. After a series of high-precision moves and adjustment of positioning, the whole process went smoothly, with error controlled to less than a millimetre.
First concrete for the foundation plate of the unit 3 nuclear island was poured in March 2021, and for the unit 4 the following December. According to China Huaneng, total investment in the construction of the second phase of the Changjiang project (units 3&4) is estimated at CNY40bn ($6.4bn). The construction period is expected to take 60 months.
Changjiang NPP already hosts two operating CNP-600 pressurised water reactors (units 1&2), which are operated by the Hainan Nuclear Energy Company and began commercial operation in 2015 and 2016. In 2021, CNNC also began construction of its ACP100 small modular reactor at the site. The 125 MWe multi-purpose pressure water reactor (Linglong One) is designed for power production, heating, steam production and desalination of sea water.
Image: Installation of the steel inner dome at Changjiang 3 (courtesy of China Huaneng)
