US engineering and technology services contractor Amentum has been awarded a £22.3 million, ten-year contract by the Civil Works Alliance to design the marine and tunnelling works at Sizewell C in Suffolk. The contract runs as a three-year design project followed by seven years of design support, extending Amentum’s role from Hinkley Point C, where it led equivalent scope.

The design scope includes three 3.5km offshore tunnels, marine shafts, tunnel-to-shaft connections, marine heads, onshore galleries, connections to the main civil works and a fish return system.

A fish return system will send fish that are accidentally drawn into the cooling circuit back to the sea, in a plant whose cooling water demand Amentum puts at “enough water to fill 4,200 Olympic swimming pools every day.”

Jacobs will provide major tunnelling design support under subcontract to Amentum, while Adda will handle 3D reinforced concrete detailing. Amentum says the team is working together again after Hinkley Point C.

Amentum senior vice president Loren Jones said: “We will bring proven nuclear design experience, replicating and enhancing lessons learned from Hinkley Point C, where we led equivalent scope.”

Jones added: “Working together again enables us to maintain continuity, leverage experience from Hinkley Point C to optimise the design, and reduce delivery risk on one of the UK’s most significant infrastructure projects.”

The structural driver is the reuse of Hinkley Point C experience, where tunnelling for the fish return system was recently completed, to reduce design risk on Sizewell’s marine works.

The Civil Works Alliance comprises Balfour Beatty, Bouygues Travaux Publics and Laing O’Rourke, which are also working on Hinkley Point C in Somerset, and preliminary construction work at Sizewell C began in January 2024.

For the sector, the award carries the firm that led equivalent scope at Hinkley Point C through to Sizewell, with design support continuing across a ten-year term.

Source: newcivilengineer.com / sustainableconstruction-now.com