The outer containment dome has been installed at unit 6 of China’s Fuqing NPP under construction in Fujian province, China National Nuclear Corporation (CNNC) has announced.

The dome, which weighs about 420 tonnes with a base diameter of about 53 metres, provides protection for the primary containment. The outer steel dome will now be covered with a concrete shell.

Fuqing 6 is the second of two demonstration Generation-III Hualong One units being built at the site. Construction began in December 2015 and commercial operation is expected in 2020 or 2021. There are six units at the Fuqing four domestic CNP1000s in commercial operation and the two Hualong One units under construction. 

The Hualong One uses a double-layer safety shell design. Together with the inner protective dome, the outer dome protects the reactor and prevents the release of radioactive materials into the environment in the event of a serious accident. The 340-tonne inner steel dome, which measures some 47 metres in diameter and over 23m in height, was installed in March 2018. CNNC said the double-layer containment shell can withstand the impact of large aircraft. The outer dome is "currently the largest shell structure of nuclear power plants under construction in the world”.

CNNC announced in 2014 that Fuqing 5&6 would the domestically-developed Hualong One pressurised water reactor design instead of the ACP1000 design previously planned. China's State Council gave final approval for construction of the two units in April 2015. First concrete for Fuqing 5  was poured in May 2015 and hot testing was completed in March this year. Fuqing 5 and 6 are scheduled to be completed in 2020 and 2021.

The outer containment dome of unit 6 at the Fuqing nuclear power plant is lifted, ready to be installed on July 25. [Photo/CNNC]