Amentum has been awarded a £22.3m contract by Sizewell C's civils contractor, the Civil Works Alliance, to design the nuclear power station's marine and tunnelling works, New Civil Engineer reported this week.

The deal runs for ten years: three years of design work followed by seven years of ongoing design support through construction. The scope covers three 3.5km offshore tunnels, marine shafts, the connections between tunnels and shafts, marine heads, onshore galleries, the tie-ins to the main civils works, and a fish return system. Amentum has subcontracted the heavy tunnelling design work to Jacobs, with Adda taking on 3D reinforced concrete detailing.

Why it matters

Sizewell C's marine and tunnelling package is one of the hardest pieces of civil engineering on the whole site: three long offshore bores driven from a nuclear construction platform, with a fish return system bolted on to satisfy environmental consent. Design contracts of this size and length do not get let unless a client expects the underlying construction programme to run for years, and a ten-year support tail tells you the Civil Works Alliance is planning for exactly that.

It is also the latest in a run of Sizewell C awards. Hinkley Point C's own fish return tunnel finished earlier this autumn, and the Avonmouth factory building the marine tunnel segments for Sizewell is already up and running. Between them, the nuclear new-build programme is now moving from early groundworks into the specialist marine and tunnelling phase, which is where the bulk of the skilled civils recruitment happens.

What it means for your career

For tunnelling engineers, marine civils specialists and anyone with offshore shaft or segmental lining experience, this is a direct signal: Amentum and Jacobs will be building design teams around this contract now, and the Civil Works Alliance will need site-side design liaison and construction management roles to follow as the work moves from drawing board to the Suffolk coast.

It is also a useful marker for QSs and commercial managers tracking the nuclear sector. A ten-year design and support contract carries its own commercial structure, change control and interface risk between designer, contractor and the wider Sizewell C supply chain, which is exactly the kind of complex contract administration that gets commercial careers built. If you are already in or around Sizewell C, or weighing a move into nuclear new-build from rail or water, this is a sign the programme has years of specialist work still to let, not months.

For project managers and engineers currently on Hinkley Point C, the timing is notable too: as Hinkley's own tunnelling work winds down, Sizewell's is only just getting going, and firms like Amentum and Jacobs are a natural landing spot for people with directly transferable experience.