Sizewell nuclear power plant
Sizewell nuclear power plant is a nuclear power station in United Kingdom with 1 operating unit totalling 1,250 MW gross. The site has 5 units on record in total.
Units
| Unit | Status | Type | Model | Gross MW | Online |
|---|---|---|---|---|---|
| Unit B | PWR | SNUPPS | 1,250 | 1995 | |
| Unit A1 | Retired | GCR | MAGNOX | 245 | 1966 |
| Unit A2 | Retired | GCR | MAGNOX | 245 | 1966 |
| Unit C1 | Pre-construction | PWR | EPR | 1,600 | - |
| Unit C2 | Pre-construction | PWR | EPR | 1,600 | - |
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.
Sizewell nuclear power plant B
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | SNUPPS |
| Size class | Large |
| Gross capacity | 1,250MW |
| Net capacity | 1,198MW |
| Thermal output | 3,425MWt |
| Enrichment | 3–5% U-235 |
| NSSS vendor | not on record |
| Owner | EDF Energy Ltd100% |
| Operator | EDF Energy |
| Construction start | 18 Jul 1988 |
|---|---|
| First criticality | 31 Jan 1995 |
| Grid connection | 14 Feb 1995 |
| Commercial operation | 22 Sep 1995 |
Live status, outage record and fuel chain for Sizewell nuclear power plant B
Sizewell nuclear power plant A1 Retired
| Reactor type | Gas-cooled reactor (GCR) |
|---|---|
| Model | MAGNOX |
| Size class | Small |
| Gross capacity | 245MW |
| Net capacity | 210MW |
| Thermal output | 1,010MWt |
| 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 Apr 1961 |
|---|---|
| First criticality | 1 Jun 1965 |
| Grid connection | 21 Jan 1966 |
| Commercial operation | 25 Mar 1966 |
| Permanent shutdown | 31 Dec 2006 |
Sizewell nuclear power plant A2 Retired
| Reactor type | Gas-cooled reactor (GCR) |
|---|---|
| Model | MAGNOX |
| Size class | Small |
| Gross capacity | 245MW |
| Net capacity | 210MW |
| Thermal output | 1,010MWt |
| 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 Apr 1961 |
|---|---|
| First criticality | 1 Dec 1965 |
| Grid connection | 9 Apr 1966 |
| Commercial operation | 15 Sep 1966 |
| Permanent shutdown | 31 Dec 2006 |
Sizewell nuclear power plant C1 Pre-construction
GNPT types the unit as a pressurized heavy water reactor, but its model is the UK EPR, which is a pressurised water reactor. Sizewell C Ltd states that the UK EPR design used at Sizewell C is the same as at Hinkley Point C and that EPRs are a type of PWR. The fuel family follows the type: an EPR takes square-lattice PWR fuel, not CANDU-style bundles.
reactor_type:
phwr → pwr
· Sizewell C Ltd, Building Sizewell C (FAQ on the UK EPR design)
· verified 2026-10-22
GNPT types the unit as a pressurized heavy water reactor, but its model is the UK EPR, which is a pressurised water reactor. Sizewell C Ltd states that the UK EPR design used at Sizewell C is the same as at Hinkley Point C and that EPRs are a type of PWR. The fuel family follows the type: an EPR takes square-lattice PWR fuel, not CANDU-style bundles.
fuel_family:
phwr → pwr
· Sizewell C Ltd, Building Sizewell C (FAQ on the UK EPR design)
· verified 2026-10-22
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | EPR |
| Size class | Large |
| Gross capacity | 1,600MW |
| Net capacity | not disclosed |
| Thermal output | not disclosed |
| Enrichment | 3–5% U-235 |
| NSSS vendor | Framatome |
| Owner | Government of United Kingdom83% EDF Energy Ltd16% |
| Milestones | no dates on record |
|---|
Sizewell nuclear power plant C2 Pre-construction
GNPT types the unit as a pressurized heavy water reactor, but its model is the UK EPR, which is a pressurised water reactor. Sizewell C Ltd states that the UK EPR design used at Sizewell C is the same as at Hinkley Point C and that EPRs are a type of PWR. The fuel family follows the type: an EPR takes square-lattice PWR fuel, not CANDU-style bundles.
reactor_type:
phwr → pwr
· Sizewell C Ltd, Building Sizewell C (FAQ on the UK EPR design)
· verified 2026-10-22
GNPT types the unit as a pressurized heavy water reactor, but its model is the UK EPR, which is a pressurised water reactor. Sizewell C Ltd states that the UK EPR design used at Sizewell C is the same as at Hinkley Point C and that EPRs are a type of PWR. The fuel family follows the type: an EPR takes square-lattice PWR fuel, not CANDU-style bundles.
fuel_family:
phwr → pwr
· Sizewell C Ltd, Building Sizewell C (FAQ on the UK EPR design)
· verified 2026-10-22
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | EPR |
| Size class | Large |
| Gross capacity | 1,600MW |
| Net capacity | not disclosed |
| Thermal output | not disclosed |
| Enrichment | 3–5% U-235 |
| NSSS vendor | Framatome |
| Owner | Government of United Kingdom83% EDF Energy Ltd16% |
| Milestones | no dates on record |
|---|
Sizewell nuclear power plant in context
By gross operating capacity Sizewell nuclear power plant is the 4th largest of 4 operating nuclear sites in the United Kingdom, holding 19% of the country's operating capacity, and ranks 129th of 172 worldwide.
Its operating unit started up in 1995; the unit is 31.0 years old, younger than the median of 37.0 in the United Kingdom.
The 3 units with both construction and grid dates on record took 4.8 to 6.6 years (median 5.0) 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 Gravelines nuclear power plant (138 km), Borssele nuclear power plant (168 km) and Doel nuclear power plant (207 km).
The current net rating of Unit B differs from its design net capacity by +0.8% (1,188 MW at design, 1,198 MW now).
Build time by unit
| Unit | Construction start | Grid connection | Years | Fleet median, same decade |
|---|---|---|---|---|
| Unit A1 | 1961 | 1966 | 4.8 | 5.0 (1960s) |
| Unit A2 | 1961 | 1966 | 5.0 | 5.0 (1960s) |
| Unit B | 1988 | 1995 | 6.6 | 8.0 (1990s) |
Nearest tracked nuclear sites
| Site | Country | Distance | Operating GW gross |
|---|---|---|---|
| Gravelines nuclear power plant | France | 138 km | 5.7 |
| Borssele nuclear power plant | Netherlands | 168 km | 0.5 |
| Doel nuclear power plant | Belgium | 207 km | 1.1 |
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.
Earthquakes nearby
Loading the latest USGS check…
| Time (UTC) | Mag | Depth | Epicentre | Distance |
|---|
Magnitude 4.0 and above within 200 km of Sizewell nuclear power plant's listed coordinates, past 30 days. This is distance, not shaking: it says nothing about damage or any change in operation. Every plant.
| Location | East Suffolk, England, United Kingdom |
|---|---|
| Coordinates | 52.2123, 1.6195 |
| Elevation | about 20 mabove sea level |
| Setting | On the sea coast, 0.7 km from the water |
| Region | Northern Europe |
| Units by status | Operating: 1 Retired: 2 Pre-construction: 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) EDF Energy Ltd Government of United Kingdom |
|---|---|
| Operators | Magnox EDF Energy |
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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