Containment dome of Hinkley Point C unit 2 installed

Thursday, 17 July 2025

The dome of the containment building has been hoisted into place at the second unit of the Hinkley Point C nuclear power plant under construction in the UK. The milestone marks the end of the major civil engineering works on the plant’s reactor buildings.

Using one of the world’s largest cranes, known as Big Carl, the dome – with a diameter of almost 47 metres, height of 14 metres and weighing 245 tonnes – was lifted and then slowly lowered onto the 44-metre-high reactor building.

The dome is made up of 38 prefabricated panels which were shipped to Hinkley Point C and welded together in an onsite factory.

_{(Image: EDF Energy)}

Work will now begin to weld an air-tight seal around the joint between the dome and the reactor building, which will then be encased with 7000 tonnes of concrete.

Construction of the first of two 1630 MWe EPR reactors at Hinkley Point C began in December 2018, with construction of unit two beginning a year later. The dome of unit 1 was put in place in December 2023.

_{(Image: EDF Energy)}

EDF Energy noted that work on unit 2 was stopped during the Covid-19 pandemic, but teams are catching up on lost time.  Their progress, it said, is helped by innovation and experience from unit 1, which means unit 2 is taking 20-30% less time to build.

Although the second dome was lifted 18 months after the first, unit 2 is further ahead, compared with the same moment for unit 1. On unit 2’s civil construction, 30% fewer people achieved 40% more work than on unit 1 with prefabrication of structures now approaching 60%, EDF Energy said. In addition, more equipment has been fitted and 300 tonnes of internal steel installed, compared with just 10 tonnes at the same stage for unit 1.

_{(Image: EDF Energy)}

“Restarting the industry has been hard, but the second of our two identical units shows the big benefits of repeating an identical design,” said Stuart Crooks, CEO of Hinkley Point C. “Build and repeat is the best way to build new nuclear with time savings already at 20-30%. All our experience and innovation will benefit Sizewell C from the start.”

Sizewell C will feature two EPRs and would essentially be a replica of the Hinkley Point C plant, with the aim of building it more quickly and at lower cost as a result of the experience gained from what is the first new nuclear construction project in the UK for about three decades.

A video of the dome lift .