Work on EDF’s Hinkley Point C nuclear power station reached a key milestone today with contractor Balfour Beatty lowering the last of six water intake tunnel head structures into position in the Bristol Channel.
The final 5,000t concrete structure was positioned in 25m water depth using two floating cranes each with a lifting capacity of 7,300t.
The six head structures – formed by four intakes fitted on two tunnels and two outfall heads on the third tunnel – form caps on the tunnels constructed by Balfour Beatty which will supply the nuclear power plant with cooling water at a rate of 120,000 litres per second. In total 9km of tunnels have been constructed – the two intake tunnels are 3.5km in length and the outfall tunnel is 1.8km long.
The size and positioning of the structures has been designed to minimise the impact of the water intake on aquatic life. The scale of structure means that the water will flow slowly into them to reduce the number of fish entering the pipes, although there are screens to allow the fish to be returned to the water, and they have also been positioned sideways on to the tidal flow.
Lifting of the structures started in mid-July and Hinkley Point C marine work project director Ian Beaumont said: “The successful installation of all six marine heads completes a summer of complex offshore operations in the most challenging of environments. Not only is it a significant milestone for the Hinkley Point C project, it also represents an incredible feat of engineering by the teams that have worked in close collaboration to design, construct and place with such precision these massive structures.”
The next phase of the work will see the connection made between the tunnels and the shafts and then with the power station itself.
The progress comes after EDF confirmed that there will be a year-long delay and £3bn cost increase to the Hinkley project.
The start date for the Unit 1 reactor at the Somerset power station will be pushed back to June 2027, with the cost now sitting at £25bn to £26bn, an increase on the previous £23bn figure.
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