The construction of the world's first AP1000 unit reached a major milestone today with the installation of the top of the containment vessel at unit 1 of China's Sanmen nuclear power plant.
|The head of the containment vessel is lowered into place (Image: SNPTC)
In a process lasting almost two hours, the containment vessel top head (CVTH) - measuring some 40 m in diameter, 11.5 m 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 operation was successfully completed on 29 January, marking the end of general construction works of the unit's nuclear island, State Nuclear Power Technology Corporation (SNPTC) 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 m 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. The 700-tonne containment vessel bottom head (CVBH) for Sanmen 1 was set in December 2009 and since then the four prefabricated ring sections of the containment vessel have been installed one on top of the other.
The installation of the CVTH follows the recent putting into place of the polar crane near the top of the fourth containment vessel ring. This crane will be used to lift reactor components and main pump components. Installation of the pressure vessel was completed in September 2011.
In September 2007, Westinghouse and its partner the Shaw Group received authorization to construct four AP1000 units in China: two at Sanmen in Zhejian province and two more at Haiyang in Shandong province.
Sanmen unit 1 is expected to be the first AP1000 to begin operating. The unit is expected to begin generating electricity in 2014. All four Chinese AP1000s are scheduled to be in operation by 2016.
Researched and written
by World Nuclear News