Distant view of Trawsfynydd nuclear power station with sheep in foreground.
Trawsfynydd Nuclear Power Station was constructed between 1959 and 1963 to architectural specifications by Sir Basil Spence. It started service in 1965 and its twin Magnox reactors generated electricity for 26 years before it reached the end of its service life in 1991. The first inland civil nuclear power station in the UK, it used fresh water for cooling drawn from Trawsfynydd lake, originally created in the 1920s as part of a hydro-electric project at Maentwrog.
The complex comprised accommodation grouped in four buildings, each of which fulfilled one of the station's distinct functions - reactor buildings, a turbine hall, fuel disposal areas and an electricity substation. These were arranged compactly and linked by covered walkways. The reactor buildings, which housed the station's twin Magnox reactors, were constructed of reinforced concrete and, at 180 feet in height, were the most dominant feature of the site. The Central Electricity Generating Board was keen to recognise that Trawsfynydd was a Welsh power station and so the practice produced a vast 'mosaic' in boulder-sized pebbles in the form of a Welsh dragon which formed the paving of the central court.
Trawsfynydd Power Station is unique in that the power station was built inland adjacent to a lake which provided cooling water when the station was operational. The power station is set within extensive landscaped grounds designed by Sylvia Crowe, who also commented on the setting of the building to complement its wider landscape within the Snowdonia National Park. After 26 years in production, the decommissioning of Trawsfynydd began in 1991. It is expected that site clearance will be carried out over the next 100 years. The reactor buildings, which remain on the site, have been be clad to become safestore buildings.
All fuel has been removed from the reactors and decommissioning is well underway. 2010 saw the implementation of the Accelerated Care and Maintenance Business Case, and activity during the reporting period was focused on the delivery of an accelerated decommissioning plan.