Skip to main content

Hinkley Point C reaches another key milestone as tunnelling commences

By Hinkley Point C media team | Posted September 19, 2019

Work has started to install the 38,000 concrete segments required to support the three underground marine tunnels at up to 33 metres below the seabed of the Bristol Channel. Once complete, the tunnels will form a critical part of Hinkley Point C’s cooling system and will have the capacity to transfer 120,000 litres of water per second. Hinkley Point C will be the first power station in the Bristol Channel to include fish protection measures.

In a first for the UK and made at Balfour Beatty’s innovative manufacturing facility in Avonmouth, pre-fabricated nuclear-grade concrete segments will be constructed to ensure that each of the three tunnel boring machines is able to deliver significant efficiency savings whilst excavating over 11 tonnes of rock per minute.

The first machine has been named Mary by local primary school children. This was in honour of Mary Anning, a local palaeontologist and fossil finder who lived her life in Lyme Regis. Mary will be able to reach a maximum speed of 120mm per minute. The 1200 tonne machine will be run by 12 operators including a pilot, with supporting teams at the surface. The team includes industry experts along with apprentices and graduate students playing a vital role in its success.

Alistair Geddes, said: “This is a significant milestone, critical to the successful delivery of the first new nuclear power station in the UK for over 20 years. Having installed the first permanent segment ahead of schedule, this milestone is testament to Balfour Beatty’s expertise and to the collaborative approach required to deliver a project of this scale and complexity.”

Rob Jordan, Hinkley Point C Construction Director said; “The start of tunnelling at Hinkley Point C represents a hidden but vitally important milestone in the construction of the UK's first new nuclear power station in a generation. The achievement underlines the continued progress being made to ensure that Hinkley Point C will be ready to supply the UK with the reliable low carbon electricity that it needs to combat climate change.”

The new power station will supply safe, secure low carbon electricity to around 6 million homes.

UK-based Balfour Beatty is contracted to three major packages of works at Hinkley Point C. It was appointed to deliver the electrical works package in a joint venture in 2015, the tunnelling and marine package in 2017 and most recently the 400kV overhead line project on behalf of National Grid in 2019. 

Related articles

Parking at Brean Beach
August 14, 2026

Supporting Local Tourism - Free Beach Parking at Brean and Berrow this Summer

Hinkley Point C is helping to make a trip to the seaside a little more affordable this summer by providing free parking at both Brean and Berrow beach car parks. Available throughout the school holidays and into October, the initiative is part of Hinkley Point C’s support for tourism businesses in Brean. The initiative has already proved extremely successful with visitors to the beach more than double the number seen in July last year.
Rebar Loading Avonmouth
August 05, 2026

What can this ship teach us about the future of nuclear construction?

This summer, a ship sailed quietly out of Bristol Port bound for Hinkley Point C in Somerset for the last time. After more than 100 sailings, the voyage marked the end of a first-of-a-kind innovation that is transforming nuclear construction in Britain.
The polar crane carefully lowered the reactor into place inside the building.
June 01, 2026

Big Carl lifts Hinkley Point C’s second nuclear reactor into place

Big Carl, the world’s largest crane, has lifted Hinkley Point C’s second nuclear reactor into place before its precision installation inside the reactor building.