San Onofre nuclear power plant
San Onofre nuclear power plant is a nuclear site in United States with 3 units on record. None is currently operating.
Units
| Unit | Status | Type | Model | Gross MW | Online |
|---|---|---|---|---|---|
| Unit 1 | Retired | PWR | - | 456 | 1968 |
| Unit 2 | Retired | PWR | CE (2-loop) DRYAMB | 1,127 | 1983 |
| Unit 3 | Retired | PWR | CE (2-loop) DRYAMB | 1,127 | 1984 |
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.
San Onofre nuclear power plant 1 Retired
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | not disclosed |
| Size class | Large |
| Gross capacity | 456MW |
| Net capacity | 436MW |
| Thermal output | 1,347MWt |
| Enrichment | 3–5% U-235 |
| NSSS vendor | not on record |
| Owner | Southern California Edison Co100% |
| Operator | Southern California Edison |
| Construction start | 1 May 1964 |
|---|---|
| First criticality | 14 Jun 1967 |
| Grid connection | 16 Jul 1967 |
| Commercial operation | 1 Jan 1968 |
| Permanent shutdown | 30 Nov 1992 |
San Onofre nuclear power plant 2 Retired
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | CE (2-loop) DRYAMB |
| Size class | Large |
| Gross capacity | 1,127MW |
| Net capacity | 1,070MW |
| Thermal output | 3,438MWt |
| Enrichment | 3–5% U-235 |
| NSSS vendor | Combustion Engineering |
| Owner | Southern California Edison Co100% |
| Operator | Southern California Edison |
| Construction start | 1 Mar 1974 |
|---|---|
| First criticality | 26 Jul 1982 |
| Grid connection | 20 Sep 1982 |
| Commercial operation | 8 Aug 1983 |
| Permanent shutdown | 7 Jun 2013 |
San Onofre nuclear power plant 3 Retired
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | CE (2-loop) DRYAMB |
| Size class | Large |
| Gross capacity | 1,127MW |
| Net capacity | 1,080MW |
| Thermal output | 3,438MWt |
| Enrichment | 3–5% U-235 |
| NSSS vendor | Combustion Engineering |
| Owner | Southern California Edison Co100% |
| Operator | Southern California Edison |
| Construction start | 1 Mar 1974 |
|---|---|
| First criticality | 29 Aug 1983 |
| Grid connection | 25 Sep 1983 |
| Commercial operation | 1 Apr 1984 |
| Permanent shutdown | 7 Jun 2013 |
San Onofre nuclear power plant in context
The 3 units with both construction and grid dates on record took 3.2 to 9.6 years (median 8.6) from construction start to grid connection; the median across all reactors connected in the 1980s is 7.3 years.
No other nuclear site with an exact position in this dataset lies within 300 km.
Build time by unit
| Unit | Construction start | Grid connection | Years | Fleet median, same decade |
|---|---|---|---|---|
| Unit 1 | 1964 | 1967 | 3.2 | 5.0 (1960s) |
| Unit 2 | 1974 | 1982 | 8.6 | 7.3 (1980s) |
| Unit 3 | 1974 | 1983 | 9.6 | 7.3 (1980s) |
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 | California, United States |
|---|---|
| Coordinates | 33.3689, -117.5548 |
| Elevation | about 25 mabove sea level |
| Setting | On the sea coast, 0.4 km from the water |
| Region | Northern America |
| Units by status | Retired: 3 |
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 | Southern California Edison Co |
|---|---|
| Operators | Southern California Edison |
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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