Onshore tunnelling completed at Hinkley Point

This milestone marks the completion of Balfour Beatty’s sprayed concrete lining works at Hinkley Point C.

Excavating through 600 metres of ground to create the tunnels, the team sprayed the ground with 9000 m3 of concrete to stabilise the underground structures. More than 1.6 million hours of work across the tunnels was completed to schedule.

The five onshore tunnels will now undergo secondary lining works, installing rebar concrete structures to further stabilise the sprayed concrete.

Balfour Beatty’s team has now completed all five onshore tunnels for the cooling water system; they will be used for transferring more than 120,000 litres of water per second to the reactors from the Bristol Channel.

The same team has also prepared three portals to facilitate the launch of the tunnel boring machines (TBM) that will excavate the tunnels for the main cooling water system. The first TBM has already set out, having travelled 2.5km at a depth of 33 metres under the Bristol Channel.

Balfour Beatty project director Alistair Geddes said: “This is a significant step forward in the successful delivery of the first new nuclear power station in the UK for over 20 years. Achieving this incredible milestone is testament to Balfour Beatty’s unrivalled expertise in delivering projects of this scale and complexity.”

Balfour Beatty is contracted to three major packages of works at Hinkley Point C. It was first appointed to deliver the electrical 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.

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