IN Brief:
- The proposed early works package carries an indicative value of £730m–£1.1bn and a core delivery period from 2028 to 2034.
- Scope includes RIBA Stage 4 design, remediation, earthworks, utilities, drainage, access, buildings, and MEP.
- GBE-N has consolidated previously separate scopes to reduce interfaces before the main SMR construction programme.
Great British Energy – Nuclear has opened preliminary market engagement on a Wylfa early works package valued at £730 million to £1.1 billion, combining civils, infrastructure, buildings, mechanical and electrical work, and bulk earthworks ahead of the main small modular reactor programme.
The proposed contract covers design from RIBA Stage 4 and delivery of ground-related enabling activities, including species relocation, remediation, site clearance, site establishment, construction utilities, drainage, haul roads, and works required to establish final ground levels. GBE-N has brought scopes previously considered as separate packages into a single procurement route to reduce interface risk between closely linked activities.
The current timetable indicates a contract running from late May 2028 to May 2034, with a possible extension to June 2037. Those dates, values, and sequencing remain indicative while the programme develops, and the notice is a market-engagement exercise rather than the launch of a final tender or a commitment to spend the upper value.
A preliminary market-engagement webinar is scheduled for 3 September 2026, between 10:00 and 11:45, giving prospective contractors an early opportunity to examine the proposed packaging, scope, and indicative contracting approach. The notice currently points to a competitive flexible procedure, with publication of the tender notice estimated for March 2027.
Preparing the site for main construction
The scope extends well beyond a conventional bulk earthworks job. Ground engineering, temporary infrastructure, utilities, drainage, access, buildings, and MEP will need to be sequenced so that later reactor and balance-of-plant packages inherit a stable, serviced, and buildable site rather than a collection of partially complete interfaces.
GBE-N’s wider Owner’s Scope includes associated developments, engineering services, main balance-of-plant, mechanical, electrical and HVAC activities, civils, and specialist works covering areas such as marine offloading and tunnelling. The early works package sits at the physical boundary between the existing site and those later construction packages, placing design coordination, programme control, and handover information alongside the more visible earthworks and infrastructure activity.
Wylfa was selected in November 2025 for the UK’s first GBE-N small modular reactor project. GBE-N and Rolls-Royce SMR signed their main contract in April 2026 for a three-unit programme expected to provide at least 1.4GW, while government support for the SMR project exceeds £2.5 billion.
The programme is also being used to build domestic nuclear delivery capacity. By June, GBE-N said it had awarded nearly £900 million of contracts since 2023, with more than 70% going to UK-registered companies, while the initial Wylfa project is expected to support around 3,000 jobs on site at peak construction.
The early works package gives the civils and building supply chain a more concrete view of the work needed before reactor installation can gather pace. Site establishment, ground preparation, drainage, haul roads, utilities, and supporting infrastructure all have to be resolved before later packages can mobilise efficiently, which places considerable programme value on work that will largely disappear beneath the finished plant.
Interface risk shapes the procurement
Combining large workstreams can simplify responsibility at programme level, although it also raises the capability threshold for the lead contractor. Managing remediation, bulk earthworks, roads, drainage, temporary utilities, structures, and MEP under one contract requires strong design management and a supply chain able to operate within nuclear governance, quality assurance, and programme-control requirements.
The market-engagement stage allows those assumptions to be tested before the tender structure is fixed. Risk allocation, sequencing, insurance, inflation exposure, temporary works, design responsibility, and the division of specialist scopes between delivery tiers will influence whether the consolidated model attracts sufficient competition and remains commercially workable.
GBE-N has explicitly stated that the current positions and timelines are based on programme assumptions that may change as design and validation progress. That qualification is important on a package whose core delivery date remains almost two years away: contractors are being asked to engage with the intended shape of the work rather than price a frozen construction scope.
Wylfa’s location on Ynys Môn adds another delivery constraint. A package approaching £1.1 billion will draw on national specialist capacity, while haulage, plant, accommodation, concrete, utilities, environmental mitigation, and workforce logistics must be coordinated around an island location over several years of construction activity.
The notice does not award work, and its upper value remains indicative. It does, however, define one of the largest construction packages yet attached to the UK’s first SMR programme, with a six-year core period and a procurement structure deliberately designed to remove interfaces before the main works arrive. The 3 September engagement session will begin testing whether that consolidation remains practical once contractors start examining where the risks actually sit.
