Amentum-Cavendish joint venture named owner's engineer for UK SMR project at Wylfa

Great British Energy has selected a joint venture between Amentum and Cavendish Nuclear as owner's engineer for its Rolls-Royce SMR project at Wylfa, North Wales. The 14-year contract, valued up to £300 million, provides independent technical assurance from design through commissioning to support final investment decision.

Great British Energy has selected a joint venture between Amentum and Cavendish Nuclear as owner's engineer for its flagship small modular reactor project at the Wylfa site in North Wales, according to an official announcement.

The contract, with a maximum value of $406 million over up to 14 years, covers independent assurance and technical advice across design, safety, engineering, construction, and commissioning. Amentum is a US-based engineering and project management firm specialising in nuclear and environmental sectors. Cavendish Nuclear is a UK-based nuclear services company.

The joint venture, operating as Litmus Nuclear, will support GBE-N's preferred reactor technology from Rolls-Royce SMR, which comprises 470 MWe reactors designed for faster construction than traditional nuclear plants. This development matters for the UK's nuclear energy strategy, where SMRs are positioned to complement large-scale plants like Hinkley Point C and Sizewell C. Wylfa was selected as the site for the UK's first SMRs in November 2025 by the Department for Energy Security and Net Zero.

For the nuclear industry, the owner's engineer appointment signals progress toward a final investment decision for the SMR programme. Stakeholders including reactor designers, construction contractors, and supply chain companies stand to benefit from project development. The contract reinforces Amentum's role in UK nuclear expansion, building on its existing work at Hinkley Point C and Sizewell C.