The containment vessel bottom head (CVBH) for unit 4 at the Haiyang nuclear power plant in China's Shandong province has been installed 40 days ahead of schedule, the Shanghai Nuclear Engineering Research and Design Institute (SNERDI) has announced.

The CVBH is hoisted into place at Haiyang 4 (Image: SNERDI)

The CVBH - weighing about 660 tonnes - is the first of six modules that will make up the unit's steel containment vessel, which will eventually have an inner diameter of 39.62 metres and a height of 65.67 metres. The vessel is designed to confine and contain radiation in the event of an accident.

The CVBH comprises 64 pre-fabricated arc-shaped steel plates, which were assembled and welded on site. It has been installed with 16 temporary supporting short columns, studs, mechanical penetrating parts and other items. In an operation lasting just over one-and-a-half hours, the component - with a total hoisting weight of about 756 tonnes - was hoisted into place on 30 June using a 3200-tonne crawler crane.

Installation of the CVBH marks "the official construction of the main structure of the nuclear island reactor building", SNERDI said. "The smooth hoisting of the CVBH module of unit 4 of the Haiyang Nuclear Power Plant has created good conditions for the subsequent critical path construction in the nuclear island reactor building, and also laid a solid foundation for the continuous construction of unit 4".

First concrete was poured for the nuclear island of Haiyang 4 in April this year. It marks the official start of construction of the second of two CAP1000 pressurised water reactors - the Chinese version of the AP1000 - planned as Phase II of the plant.

The planned construction period for Haiyang 3 and 4 is 56 months.

Researched and written by World Nuclear News