620m Hinkley Point C Tunnel Breaks Through Seabed

A 620-metre tunnel beneath the Bristol Channel has been completed at Hinkley Point C, with the tunnel boring machine subsequently recovered from the seabed by floating crane.

The tunnel forms part of the nuclear power station’s fish return system and was completed five months after the TBM, named Sarah Guppy by local schoolchildren, began its drive from dry land.

Following breakthrough, the machine was lifted from the seabed and will now be cleaned and prepared for use on another project.

The tunnel forms part of Hinkley Point C’s wider fish protection system, designed to reduce the impact of cooling-water intake operations on marine life.

Alongside the return tunnel, the project includes an acoustic fish deterrent and four low-speed water intakes designed to allow fish to swim away from the system.

The completion of the drive marks another major tunnelling milestone at Hinkley Point C, combining subsea construction with a complex offshore recovery operation.