Trawsfynydd nuclear power plant
Trawsfynydd nuclear power plant is a nuclear site in United Kingdom with 2 units on record. None is currently operating.
Units
| Unit | Status | Type | Model | Gross MW | Online |
|---|---|---|---|---|---|
| Unit 1 | Retired | GCR | MAGNOX | 235 | 1965 |
| Unit 2 | Retired | GCR | MAGNOX | 235 | 1965 |
Unit by unit
Each unit's rating, type and milestone dates as recorded by the Global Nuclear Power Tracker, with any correction we made to it. A dash or "not disclosed" means the source does not give the value.
Trawsfynydd nuclear power plant 1 Retired
| Reactor type | Gas-cooled reactor (GCR) |
|---|---|
| Model | MAGNOX |
| Size class | Small |
| Gross capacity | 235MW |
| Net capacity | 195MW |
| Thermal output | 850MWt |
| Enrichment | Natural uranium to 2.5–3.5% U-235no enrichment required |
| NSSS vendor | not on record |
| Owner | Nuclear Decommissioning Authority (United Kingdom)100% |
| Operator | Magnox |
| Construction start | 1 Jul 1959 |
|---|---|
| First criticality | 1 Sep 1964 |
| Grid connection | 14 Jan 1965 |
| Commercial operation | 24 Mar 1965 |
| Permanent shutdown | 6 Feb 1991 |
Trawsfynydd nuclear power plant 2 Retired
| Reactor type | Gas-cooled reactor (GCR) |
|---|---|
| Model | MAGNOX |
| Size class | Small |
| Gross capacity | 235MW |
| Net capacity | 195MW |
| Thermal output | 850MWt |
| Enrichment | Natural uranium to 2.5–3.5% U-235no enrichment required |
| NSSS vendor | not on record |
| Owner | Nuclear Decommissioning Authority (United Kingdom)100% |
| Operator | Magnox |
| Construction start | 1 Jul 1959 |
|---|---|
| First criticality | 1 Dec 1964 |
| Grid connection | 2 Feb 1965 |
| Commercial operation | 24 Mar 1965 |
| Permanent shutdown | 4 Feb 1991 |
Trawsfynydd nuclear power plant in context
The 2 units with both construction and grid dates on record took 5.5 to 5.6 years (median 5.6) from construction start to grid connection; the median across all reactors connected in the 1960s is 5.0 years.
The nearest other tracked nuclear sites are Heysham nuclear power plant (141 km), Hinkley Point nuclear power plant (199 km) and Hartlepool nuclear power plant (263 km).
Build time by unit
| Unit | Construction start | Grid connection | Years | Fleet median, same decade |
|---|---|---|---|---|
| Unit 1 | 1959 | 1965 | 5.5 | 5.0 (1960s) |
| Unit 2 | 1959 | 1965 | 5.6 | 5.0 (1960s) |
Nearest tracked nuclear sites
| Site | Country | Distance | Operating GW gross |
|---|---|---|---|
| Heysham nuclear power plant | United Kingdom | 141 km | 2.6 |
| Hinkley Point nuclear power plant | United Kingdom | 199 km | - |
| Hartlepool nuclear power plant | United Kingdom | 263 km | 1.3 |
How these are worked out: ranks use gross operating capacity; ages count from the start-up year on record, as on the age page; build times run from construction start to grid connection, as on the build-times page; ratings are the tracker's net and design net capacity, as on the uprates page. Distances are straight-line between exact positions, so a site with only an approximate position gets none. A unit missing a date or a rating is left out of the figure that needs it.
| Location | Wales, United Kingdom |
|---|---|
| Coordinates | 52.9252, -3.9474 |
| Elevation | about 200 mabove sea level |
| Setting | 7.9 km from the sea |
| Region | Northern Europe |
| Units by status | Retired: 2 |
Elevation is read at the listed coordinates from a 30 m terrain model (SRTM 30 m). Two independent models differ by a median of 6 m across our plants and by up to about 40 m on steep or coastal ground, and a point on a shoreline can read as sea level. Distance to the water is measured to a generalised 1:10 million coastline, so a few kilometres or less is not resolved. This is context, not a design-basis or flood-risk figure.
| Owners | Nuclear Decommissioning Authority (United Kingdom) |
|---|---|
| Operators | Magnox |
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Sources
- Global Nuclear Power Tracker, Global Energy Monitor, August 2026 release , CC BY 4.0 · retrieved 2026-09-06
- GEM.wiki entry (further reading) , CC BY-SA 4.0, linked, not quoted
How these sources are used, including the corrections applied on top of them and what is deliberately left blank · download the underlying data