A tunnelling machine has broken through the seabed under the Bristol Channel after finishing a 620-metre fish return tunnel at Hinkley Point C.
EDF says the machine, named Sarah Guppy, dug its way out of the seabed five months after setting off from dry land.
It has now been lifted clear by a floating crane and will be taken away to be cleaned before being used on another site.
The tunnel is the last of the marine tunnels on the project, bringing the total length of tunnels under the channel to 8km.
The power station is moving into its fit-out phase, with both nuclear reactors now installed and work under way to fit the world’s largest turbine.
The fish return system is one of three measures designed to protect marine life around the site.
EDF says the combined package will give the station more fish protection than any other power station in the world.
The other measures are an acoustic fish deterrent and four low-speed water intakes. The intakes are designed so that fish can swim clear from as close as two metres in the 20km-wide channel. Any fish that do enter the cooling system are to be carried back out to sea through the new tunnel.
The tunnel boring machine was named Sarah Guppy by local schoolchildren, after the pioneering 19th-century engineer from Bristol. Engineers prepared to start the drive in March. The tunnel is 1.8 metres in diameter.
Hinkley Point C is due to open in 2031. Once running, the two reactors are expected to supply enough electricity for up to six million homes.
