Three steel rings that comprise the walls of the main containment shell have been installed at unit 3 of China’s Sanmen NPP in Zhejiang province. The total hoisting weight was about 826 tonnes, according to the Shanghai Nuclear Engineering Research and Design Institute (SNERDI).
Each ring has a wall thickness of almost 4.5 centimetres, an inner diameter of about 39.6 metres and an overall height of 11.6 metres. Also installed were temporary stiffening ribs, accessory plates, air deflector brackets, guide devices, lifting ears and other items on the shell, pipelines, electrical, ventilation, steel structures and electric winches to save installation time and improve on-site work efficiency.
The construction of two new units at each of the Sanmen (3&4), Haiyang (3&4) and Lufeng (5&6) NPPs was approved by China’s State Council in April 2021. Two Westinghouse AP1000 units built as Phase I of the Sanmen plant (1&2) started operation in 2018. Two CAP1000 reactors are being constructed as Phase II of the plant (units 3&4). First concrete was poured for the nuclear island of Sanmen 3 in June 2022 and for unit 4 in March 2023.
The CAP1000 is China’s version of the Westinghouse AP1000. It uses modular construction techniques, enabling large structural modules to be built at factories and then installed at the site. This reduces construction time and improves quality control.
First concrete was poured for the nuclear island of Sanmen 3 in June 2022 and first concrete for unit 4 in March 2023. The units are expected to be connected to the grid in 2027 and 2028.
