Construction of the second AP1000 unit at Sanmen in China's Zhejiang province reached a milestone yesterday with the installation of the top of the containment vessel.
|The dome is raised prior to being placed on top of the containment walls (Image: CNEC)
In an operation lasting two hours, the containment vessel top head - measuring some 40 meters in diameter, 11.5 meters high and weighing about 655 tonnes - was raised by crane and lowered into place on top of the fourth ring of the containment building. The installation of the containment dome marks the end of general construction works of the unit's nuclear island, State Nuclear Power Technology Corporation reported.
The containment vessel is a high integrity, freestanding steel structure with a wall thickness of almost 4.5 cm. The containment is 39.6 meters in diameter. The ring sections and vessel heads are constructed of steel plates pre-formed in an off-site fabrication facility and shipped to the site for assembly and installation using a large-capacity crane.
Two AP1000s are under construction at the Sanmen site, with another two being built at Haiyang in Shandong province. Sanmen unit 1, construction of which began in April 2009, is expected to be the first AP1000 to begin operating. First concrete for Sanmen 2 was poured in December 2009. All four Chinese AP1000s are scheduled to be in operation by 2016.
Last month, plant constructor China Nuclear Engineering Corporation (CNEC) announced that the second steam generator - measuring 24 metres in length, 5.5 metres in diameter and weighing 640 tonnes - was hoisted into place by crane on 15 June. The first was installed in late April.
Four further AP1000 reactors are currently being built in the USA - two each at Vogtle and Summer - while three AP1000s are also proposed for the Moorside site in the UK.
Researched and written
by World Nuclear News