THE cause of a mystery sound which has been heard along the Somerset coastline from Minehead and Watchet to Weston-super-Mare has been identified as off-shore work for the Hinkley Point C nuclear power station.

Concern had been expressed by people living in coastal communities about an eerie-sounding banging noise and vibrations in the ground.

Earlier this month, two huge jack-up vessels, Neptune and Sea Challenger, arrived off-shore at Hinkley C to on the seabed install vital components for the power station’s cooling water system.

The platforms will be used for creating six vertical shafts at a depth of more than 65 feet to help connect six miles of tunnels with the seabed.

Miners will dig a horizontal connection from the shafts and the tunnels to link to 5,000 tonne intake and outfall heads which will circulate water to the power station’s two nuclear reactors.

Hinkley C senior stakeholder relations manager Andrew Cockcroft said: “Over the next three months, Hinkley Point C will move into the final phase of its marine works.

“We have notified residents living near the site that this activity has the potential to cause intermittent noise disturbance.

“We will monitor noise levels and are committed to ensuring these works are delivered with minimal disruption to residents and apologise for any inconvenience caused.”

Hinkley C area delivery director Jonathan Smith said: “This is one of the final stages of our off-shore operations, which will see teams from EDF, Balfour Beatty, and New Wave Solutions working together to deliver yet another incredible feat of engineering.

“The cooling water system is critical to the power station, which will help Britain fight climate change and achieve stronger energy security.”

Balfour Beatty project director Roger Frost said: “The arrival of Neptune and Sea Challenger marks another significant step forward in the successful delivery of the first new nuclear power station in the UK for over 20 years.

“We now look forward to utilising our unique capability and unrivalled expertise to continue with the linking up of the six miles of tunnels which are buried below the Bristol Channel.

“This is another important chapter in the off-shore works required for Hinkley C’s critical water-cooling system.”

Residents living near Hinkley Point were told in a letter from EDF earlier this month the construction would move into the final phase of off-shore marine works from the middle of April. 

The letter stated: “This activity has the potential to cause intermittent noise disturbance over the next three months.

“We will monitor noise levels and adjust working times to limit any disturbance to residents close to the Hinkley Point C site.

“There is the possibility that, for short periods of time, noise levels will be above the limits set out in the Development Consent Order.”