Cooling system progress at Hinkley Point 08 Oct 2020

Excavation of the onshore cooling water systems for the new nuclear power plant at Hinkley Point in the UK is complete with three TBM headings under the sea for two intake and one outlet tunnels progressing. News from Balfour Beatty, the contractor for the cooling water system tunnels for EDF Energy, owner of the new nuclear power project, reports successful breakthrough of the longest and final onshore cooling-water tunnel. The breakthrough marks the end of 600m of sprayed concrete lining works for the project. The five onshore tunnels will undergo casting of the secondary rebar reinforced concrete lining.

Last of five SCL on-shore cooling water headings now complete

At the same time, Balfour Beatty crews are managing excavation of the three marine cooling water system TBM headings. The first TBM launched at the end of August 2019 and has progressed more than 2.5km into the first 3.5km x 6m i.d. segmentally lined drive, 33m out under the Bristol Channel. The cooling water system will transfer more than 120,000 litre/sec of water to the new power plant from the Bristol Channel.

Alistair Geddes, Project Director for the Balfour Beatty Hinkley Point C tunnelling and marine project, said that "this is significant progress towards delivery of the first new nuclear power station in the UK for more than 20 years. It is an achievement 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 £460 million electrical package in a joint venture with NG Bailey in 2015 to delivery design and installation of more than 3,000km of cabling, installation of fire and environmental sealing, and design and installation of earthing systems.

In 2017 it was awarded the four-year contract to construct the three tunnels of the cooling water system, both onshore and offshore. The package includes two 3.3km cooling water intake tunnels, one for each of the two pressurised water reactors of the new plant, and a shared 1.8km long x 7m diameter water outfall tunnel (Fig 1). Balfour Beatty took over the contract from Costain, the original preferred bidder for the works.

Most recently, in 2019, it is awarded the £214 million to design, supply, install, test and commission a new 400kV overhead line spanning 48.4km on behalf of National Grid.

TBMs 2 and 3 are yet to launch on their undersea marine headings.