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Dome lift happening with the title 'Hinkley Point C in 2023'

Lifting The Dome

Posted April 24, 2024

What is it?
The dome is the top part of the reactor building’s ‘inner containment’, which is a steel barrier encased in concrete. It prevents radioactive particles from escaping in the unlikely event of an incident and has been built to withstand an aircraft impact or an earthquake. 

Understanding the importance
The closing of the roof now allows the installation of vital equipment that can’t be exposed to the weather. The domed roof has been placed onto the first reactor building, taking advantage of a weather window so the lift could be completed in calm conditions.

What’s next?
Now the dome is in place, progress can be made in a weatherproof building, a pivotal shift to focusing on the installation of the mechanical and electrical phase of the power station – including its heating, ventilation and air conditioning systems. This phase of work will also involve fitting the necessary pipes and cables.

What preparation was involved?
Before the lift, key equipment needed to be fitted. The Reactor Pressure Vessel support ring was installed. This will keep the reactor itself in position. The tanks that hold cooling water were also fitted. The installation of the Polar Crane was another essential step.

How did it happen?
Big Carl, the world’s largest land-based crane, lifted the dome into place. The team hooked up hydraulic units underneath the crane to the framework of steel that helps keep heavy loads balanced. 

The lifting gear was moved into position and connected a set of slings attached to the dome. The slings were individually adjusted in sequence, and readings were taken to ensure the weight of the dome was evenly distributed.

With the slings in position, the weight of the dome was gradually lifted off its supports. It then made its way onto the reactor building before landing safely on a set of adjustable jacks. The dome was levelled up using the jacks before the crane equipment was released.

How does it measure up?
The dome weighs 245 tonnes and measures 47 metres in diameter. It’s made up of 38 prefabricated panels that were shipped to Hinkley Point C and welded together onsite using around 900 metres of welds.

Did you know?
This dome is wider than the dome of St Paul’s Cathedral.

We have lift-off!
Click here to see the dome lift in action.

They did it!
As you can imagine, successfully lifting the dome into position was no small feat. It took preparation, consideration, and cooperation, with hundreds of people working thousands of hours.

Sixteen contractors – including Bylor, Tissot and Framatome – played their part inside the building, getting the internal structures, equipment and fitting ready for the dome lift. There were also 17 different suppliers involved, with Sarens, Fayat, APCO and the MEH Alliance being just a few examples.

It took a huge collaborative effort to complete the lift, which has been described as ‘historic’, ‘symbolic’, and ‘monumental’.

Contributor comments

This dome lift is a significant milestone for Hinkley Point C and the wider energy industry. It’s been the result of outstanding collaborative working across the project. I’m one of three family members lucky enough to work on the project. I feel honoured and proud to play my part in delivering our commitment to net zero.

Emma Draper, Hold Point Manager, EDF


I was humbled to see the great efforts from the dome lift team to not only deliver the plan but to overcome the challenges. The commitment and dedication of everyone involved has led to this achievement.

Matt Hargreaves, Area Delivery Manager, EDF


Four years ago, we landed the first cup into the Reactor 1 building. The pressure was enormous. We’ve now landed the dome in full confidence. Over the years on site the team has constantly learned and improved, securing a strong reputation.

Simon Gould, Construction Superintendent, Tissot


I am so proud of the whole team in achieving this historic milestone. The work that has happened to make the dome lift possible is incredible. We’ve worked as an integrated team. The team worked day and night to construct the complex puzzle that is the reactor building internal structures.

Mike Dowling, Project Leader, Bylor


I watched it with a lot of the bus drivers on site who’d brought people in that morning. It felt like something monumental. For the last few metres when it was being put in place, everything came to a standstill. It really was symbolic and memorable. Everything’s changed because of it. When you go to site now, the dome that was sat on the floor, is now part of the skyline. Being local, someone who has brought up children in and around the area, I know they are going to reap the benefits of this project.

Jon Peters, Duty Operations Manager, Somerset Passenger Solutions

A cause to celebrate
To mark the momentous milestone, more than 350 team members who played their part in the dome lift attended a special event as a thank you for their contributions.

Catering contractor Somerset Larder baked 12,000 biscuits and cupcakes for the workforce to enjoy during the celebrations. Chefs Rosemary Overall and Jackie Davies baked a showstopping sponge which was decorated to look like the dome and weighed a mighty 50kg.

Rosemary said: "We’ve never baked anything quite like this before – in fact, it took us four days to prepare before we could even pop it in the oven!”

Our Dome Lift cake was made from:
  • 60kg flour
  • 350 eggs
  • 25kg icing


As I stood in the early morning light at site and watched the 245-tonne dome being lifted by the crane known as ‘Big Carl’, I was filled with an immense sense of pride. Through great teamwork and dogged determination, we have delivered.

Stuart Crooks, Managing Director – Hinkley Point C

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