Millstone nuclear power plant
Millstone nuclear power plant is a nuclear power station in United States with 2 operating units totalling 2,198 MW gross. The site has 3 units on record in total.
Units
| Unit | Status | Type | Model | Gross MW | Online |
|---|---|---|---|---|---|
| Unit 2 | PWR | CE 2LP (DRYAMB) | 918 | 1975 | |
| Unit 3 | PWR | WH 4LP (DRYSUB) | 1,280 | 1986 | |
| Unit 1 | Retired | BWR | - | 684 | 1971 |
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.
Millstone nuclear power plant 2
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | Combustion Engineering 2-loop |
| Size class | Large |
| Gross capacity | 918MW |
| Net capacity | 869MW |
| Thermal output | 2,700MWt |
| Enrichment | 3–5% U-235 |
| NSSS vendor | Combustion Engineering |
| Owner | Dominion Resources Inc100% |
| Operator | Dominion Energy |
| Construction start | 1 Nov 1969 |
|---|---|
| First criticality | 17 Oct 1975 |
| Grid connection | 9 Nov 1975 |
| Commercial operation | 26 Dec 1975 |
Live status, outage record and fuel chain for Millstone nuclear power plant 2
Millstone nuclear power plant 3
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | Westinghouse 4-loop |
| Size class | Large |
| Gross capacity | 1,280MW |
| Net capacity | 1,210MW |
| Thermal output | 3,650MWt |
| Enrichment | 3–5% U-235 |
| NSSS vendor | Westinghouse Electric Company |
| Owner | Dominion Resources Inc100% |
| Operator | Dominion Energy |
| Construction start | 9 Aug 1974 |
|---|---|
| First criticality | 23 Jan 1986 |
| Grid connection | 12 Feb 1986 |
| Commercial operation | 23 Apr 1986 |
Live status, outage record and fuel chain for Millstone nuclear power plant 3
Millstone nuclear power plant 1 Retired
| Reactor type | Boiling water reactor (BWR) |
|---|---|
| Model | not disclosed |
| Size class | Large |
| Gross capacity | 684MW |
| Net capacity | 641MW |
| Thermal output | 2,011MWt |
| Enrichment | 3–5% U-235 |
| NSSS vendor | not on record |
| Operator | Dominion Energy |
| Construction start | 1 May 1966 |
|---|---|
| First criticality | 26 Oct 1970 |
| Grid connection | 29 Nov 1970 |
| Commercial operation | 1 Mar 1971 |
| Permanent shutdown | 1 Jul 1998 |
Millstone nuclear power plant in context
By gross operating capacity Millstone nuclear power plant is the 20th largest of 54 operating nuclear sites in the United States, holding 2% of the country's operating capacity, and ranks 76th of 172 worldwide.
Its operating units started up between 1975 and 1986; the median unit is 45.5 years old, older than the median of 45.0 in the United States.
The 3 units with both construction and grid dates on record took 4.6 to 11.5 years (median 6.0) from construction start to grid connection; the median across all reactors connected in the 1970s is 5.4 years.
The nearest other tracked nuclear sites are Seabrook nuclear power plant (207 km).
2 operating units are rated differently now from their design net capacities: Unit 2 -0.1% and Unit 3 +4.4%.
Build time by unit
| Unit | Construction start | Grid connection | Years | Fleet median, same decade |
|---|---|---|---|---|
| Unit 1 | 1966 | 1970 | 4.6 | 5.4 (1970s) |
| Unit 2 | 1969 | 1975 | 6.0 | 5.4 (1970s) |
| Unit 3 | 1974 | 1986 | 11.5 | 7.3 (1980s) |
Nearest tracked nuclear sites
| Site | Country | Distance | Operating GW gross |
|---|---|---|---|
| Seabrook nuclear power plant | United States | 207 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.
Earthquakes nearby
Loading the latest USGS check…
| Time (UTC) | Mag | Depth | Epicentre | Distance |
|---|
Magnitude 4.0 and above within 200 km of Millstone 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 | Connecticut, United States |
|---|---|
| Coordinates | 41.3107, -72.1677 |
| Elevation | about 10 mabove sea level |
| Setting | On the sea coast, 1.2 km from the water |
| Region | Northern America |
| Units by status | Operating: 2 Retired: 1 |
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 | Dominion Resources Inc |
|---|---|
| Operators | Dominion 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