ILIOS selected for STEP fusion prototype: civil design and risk notes for engineers
Reviewed by Tom Sullivan
First reported on The Construction Index
30 Second Briefing
ILIOS, a Kier–Nuvia joint venture backed by Aecom, AL_A Architects and Turner & Townsend, has secured a £200m principal design-and-build contract for the STEP spherical tokamak fusion prototype at the former West Burton power station in Nottinghamshire. Under STEP Fusion and UKAEA’s UK Fusion Energy, ILIOS will manage all enabling works, civil engineering, buildings and site infrastructure, including design integration, logistics and supply chain coordination. The build programme targets first operation around 2040, with the key technical objective of achieving net energy output to prove commercial fusion viability.
Technical Brief
- ILIOS must coordinate design integration across reactor structures, buildings and site-wide infrastructure under STEP leadership.
- Responsibilities extend to supply chain management, logistics and construction sequencing to suit complex nuclear-grade assembly.
- Programme director Simon Matthews flags development of a long-term, UK-based fusion supply chain as a core objective.
Our Take
Kier’s role at the West Burton STEP site comes as it is simultaneously securing major UK public frameworks in roads, hospitals and schools in our database, suggesting the group is positioning its construction arm as a go‑to delivery partner for complex, long‑horizon public infrastructure.
With STEP aiming for operation around 2040, the West Burton project sits at the extreme long end of the 713 Infrastructure stories in our coverage, meaning early design and enabling works will need unusually robust risk allocation and inflation assumptions compared with typical 5–10 year UK frameworks.
Locating a fusion prototype in Nottinghamshire rather than traditional nuclear hubs implies UKAEA and UK Fusion Energy are testing how far existing regional supply chains and skills bases can be repurposed, which will matter for contractors like Nuvia and Aecom looking to build a repeatable fusion delivery model beyond this single site.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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