Font Size

100% 150% 200%

Background Colour

Default Contrast
Close Reset

Trawsfynydd Nuclear Power Station

Power Station (20th Century)

Site Name Trawsfynydd Nuclear Power Station

Classification Power Station (20th Century)

Alternative Name(s) Wales

Canmore ID 286966

Site Number SH63NE 1

NGR SH 6910 3803

Datum OSGB36 - NGR


Ordnance Survey licence number 100057073. All rights reserved.
Canmore Disclaimer. © Copyright and database right 2019.

Toggle Aerial | View on large map

Digital Images

Administrative Areas

  • Council Gwynedd
  • Parish Maentwrog
  • Former Region Not Applicable
  • Former District Not Applicable
  • Former County Not Applicable

Sir Basil Spence

Building Notes

In 1958 the Central Electricity Generating Board received consent from the Minister of Power to construct their fourth nuclear power station. The station was located in North Wales, at the heart of Snowdonia National Park, near the village of Lyn Trawsfynydd. As the first station of this kind to be built inland, Trawsfynydd obtained water for its cooling system from a man-made, freshwater reservoir built in the 1920s to service a nearby hydroelectric project. Basil Spence & Partners acted as Architectural Consultants in the design of the power station, which was in full operation by 1965. Sylvia Crowe, who worked with Spence at a number of his other buildings, was Landscape Architect for the project.

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.

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, will be clad to become safestore buildings.

Archive Details and Summary

The Sir Basil Spence Archive holds two manuscript files, 23 drawings and 24 photographs relating to Trawsfynydd. The manuscript material explains the importance of landscaping in Trawsfynydd's design: located in national parkland, it was felt that the plant should intrude as little as possible upon the sensitive nature of its surroundings. Soil and rock, which had been removed during the excavations, were used to soften the newly constructed areas and a further attempt to unify the building with the site was made by the use of local stone aggregate for the concrete. Also included are a project description, a visitor's pass for the station, and a journal article about 'Boiling Water Nuclear Reactors'.

The photographs of the project include views of Sir Basil Spence and Dame Sylvia Crowe meeting HRH Queen Elizabeth II at the Trawsfynydd Royal Opening Ceremony on 10 August 1963. The drawings include perspective sketches produced by Spence himself.

This text was written as one of the outputs of the Sir Basil Spence Archive Project, supported by the Heritage Lottery Fund, 2005-08.

Archaeology Notes

SH63NE 1 6910 3803

The Royal Commission on the Ancient and Historical Monuments of Wales has further information on this site which is accessible through their online database Coflein; for details, follow this link:

Information from B Malaws (RCAHMW) 27 February 2008


MyCanmore Image Contributions

Contribute an Image

MyCanmore Text Contributions