As reported on 8 October 2026, Nuclear Restoration Services handed responsibility for the reactor buildings area at Trawsfynydd to Costain, following the award of a contract in October 2025 to deliver reactor height reduction. The project, one of the largest programmes across the NRS estate, is intended to reduce the height of both reactor buildings by nearly half.

NRS said the handover marked the move from planning and preparation into on-site delivery, and that a key project review had confirmed plans were progressing as expected. A crane was already on site for early activities including scaffolding, hoist installation and electrical works. Large crawler cranes were expected later in 2026, followed in early 2027 by two tower cranes inside the reactor buildings.

At its peak the programme was expected to create more than 100 jobs with Costain. Site Director Tom Williams said the milestone reflected years of planning and that experience gained would inform future decommissioning programmes across the NRS estate.