Trawsfynydd
Blaenau Ffestiniog, Gwynedd
Reactor Data
Reactor Units
Every power reactor at this site as listed in the IAEA Power Reactor Information System (PRIS): reactor type and model, net electrical capacity, grid connection and commercial operation dates, and current status.
2 units: 2 permanent shutdown.
| Unit | Type | Model | Net MWe | Construction | Grid | Commercial Op | Shutdown | Status |
|---|---|---|---|---|---|---|---|---|
| Trawsfynydd 1 | GCR | MAGNOX | 195 | 1959-07-01 | 1965-01-14 | 1965-03-24 | 1991-02-06 | Permanent Shutdown |
| Trawsfynydd 2 | GCR | MAGNOX | 195 | 1959-07-01 | 1965-02-02 | 1965-03-24 | 1991-02-04 | Permanent Shutdown |
Capacity, milestones and suppliers
| Unit | Design MWe | Gross MWe | Thermal MWt | First Criticality | Reactor Supplier | Turbine Supplier | Notes |
|---|---|---|---|---|---|---|---|
| Trawsfynydd 1 | 250 | 235 | 850 | 1964-09-01 | ATOMIC POWER CONSTRUCTION, LTD. | Richardsons Westgarth | |
| Trawsfynydd 2 | 250 | 235 | 850 | 1964-12-01 | ATOMIC POWER CONSTRUCTION, LTD. | Richardsons Westgarth |
Lifetime performance, through 2025
| Unit | Electricity Supplied | Load Factor | Energy Availability | Operating Factor |
|---|---|---|---|---|
| Trawsfynydd 1 | 35.2 TWh | 79.4% | 78.4% | 91.8% |
| Trawsfynydd 2 | 35.2 TWh | 79.4% | 78.4% | 91.8% |
Operator: MAGNOX, LTD
Owner: Nuclear Decommissioning Authority
Source: IAEA Power Reactor Information System (PRIS), as of 2026-10-19.
Working Here
Per Diem Rates FY 2026
Per diem covers lodging and meals & incidental expenses (M&IE) for government and contractor travel near this facility. Rates are from the U.S. State Department foreign per diem tables for FY 2026.
$252
Lodging/Night
$108
M&IE/Day
$360
Total/Day
United Kingdom: rate for locations the State Department does not list separately
U.S. Department of State foreign per diem, for U.S. government and contractor travel.
Photos
Photos of this facility from the NukeWorker photo gallery. Click the header or any photo to browse the full album.
Facility Map
Interactive satellite map showing the facility's geographic location. Marker color indicates current status: green for online, red for offline, orange for reduced power. Click the header to open in Google Maps satellite view.
52.9252, -3.94828
Location & Contact
Physical address, phone number, and website for this facility. Use the directions link to get driving directions via Google Maps.
Plant Facts
About This Site
Written by NukeWorker from public records: facts that do not change. Operator, status and capacity come from the live data elsewhere on this page. Sources: Wikipedia: Trawsfynydd nuclear power station.
Trawsfynydd is a nuclear power station site in Gwynedd, Wales, within Snowdonia National Park. It was built inland beside Llyn Trawsfynydd, an artificial reservoir that supplied its cooling water. It had two Magnox reactors.
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Construction began in July 1959. Both reactors were operating by March 1965, and the station was fully opened in October 1968. Both reactors were permanently shut down in February 1991. Between 1993 and 1997, the spent fuel was removed and sent by rail to Sellafield, and the last train carrying nuclear material left the site on 22 April 1997.