Inner dome installed at first Zhangzhou Hualong One

The steel dome - measuring 45 metres in diameter and almost 14 metres in height, and weighing about 260 tonnes - was raised by crane and placed on top of the walls of the double containment structure. An outer dome will subsequently be installed over the inner one.

CNNC said the installation of the dome is an important milestone in the construction of nuclear power projects. The dome is located on top of the nuclear island. Its main function is to ensure the integrity and leak tightness of the reactor building, and it plays a key role in the containment of radioactive substances.

The company noted that, with the installation of the inner dome now complete, the project has now "shifted from the construction stage to the installation stage."

The reactor pressure vessel (RPV) was installed at Zhangzhou 1 earlier this month. At that time, CNNC said the main nuclear island equipment - including the RPV and steam generators - were now in place, "a prerequisite for the subsequent dome hoisting and main pipeline welding."

China's Ministry of Ecology and Environment issued construction licences for Zhangzhou units 1 and 2 on 9 October 2019 to CNNC-Guodian Zhangzhou Energy Company, the owner of the Zhangzhou nuclear power project which was created by CNNC (51%) and China Guodian Corporation (49%) in 2011. The licences are valid for 10 years. Construction of unit 1 began one week after the issuance of the construction licence, with that of unit 2 starting in September 2020. The units are scheduled to enter commercial operation in 2024 and 2025, respectively.

CNNC began construction of two demonstration Hualong One units at its Fuqing plant in Fujian province in May and December 2015, respectively. The first of these, Fuqing 5, was connected to the grid on 27 November last year, having achieved first criticality on 21 October, and entered commercial operation on 30 January this year. Fuqing 6 is expected to begin operating by the end of 2021.

Construction of two demonstration Hualong One (HPR1000) units is also under way at China General Nuclear's Fangchenggang plant in the Guangxi Autonomous Region. Those units are expected to start up in 2022. CNNC has also started construction of the first of two Hualong One units at Taipingling in Guangdong.

Two HPR1000 units are under construction at Pakistan's Karachi nuclear power plant. Construction began on Karachi unit 2 in 2015 and unit 3 in 2016; the units are planned to enter commercial operation in 2021 and 2022.