EDF has installed the dome at unit 1 of the Hinkley Point C NPP.

The installation of the reactor building dome was undertaken using one of the world's largest cranes, known as Big Carl. The 245-tonne dome, with a diameter of almost 47 metres and a height of 14 metres, was lifted and then slowly lowered into place onto the 44-metre-high reactor building. This marked the end of the major civil engineering works on the reactor buildings. Work will now start to weld an air-tight seal around the joint between the dome and the reactor building, which will then be encased with 7,000 tonnes of concrete.

The dome is made up of 38 prefabricated panels which were shipped to Hinkley Point C and welded together in an onsite factory.  Prefabrication and modular construction are key features of Hinkley Point C’s construction, which EDF said involves around 10,000 workers and 3,500 British companies. Earlier in December, the 750 tonne polar crane was lifted into place in a single piece above the reactor building’s third – and final – steel liner ring. This internal crane will rotate 360° above the reactor and be used for refuelling and installing equipment.

Hinkley Point C, when complete, will comprise two 1,630 MWe EPR reactors supplied by EDF. Construction began in December 2018 but the project has faced delay challenges. In May 2022 EDF, following a review of the project, confirmed that the plant would begin operating a year later than planned and could cost up to £3bn ($3.7bn) more to build than originally budgeted. This put the start date for unit 1 at June 2027, with the cost estimated at £25-26bn, an increase on the previous estimate of £23bn.

"Building the first nuclear power station in a generation is a challenging job and the success of this complex operation is due to the determination and commitment of our fantastic teams," said Simon Parsons, Nuclear Island Area Director. "Lifting the dome allows us to get on with the fitting of equipment, pipes and cables, including the first reactor which is on-site and ready to be installed next year."

UK Nuclear Minister Andrew Bowie said this is “a major milestone in building Britain’s first nuclear reactor in a generation, and a key part of the UK Government’s plans to revitalise nuclear”. He added: "Generating enough zero-carbon power for six million homes, Hinkley Point C will reduce our reliance on imported energy and support our shift to net-zero."

In 2021, EDF said the start of electricity generation from unit 1 had been rescheduled to June 2026. Moreover, delays arising from the COVID-19 pandemic will also increase the cost of the project by £500m to £22-23bn. EDF the following year announced a further delay in operation to June 2027 and that project completion costs would be in the range of £25-26bn.


Image courtesy of EDF