Mihama nuclear power plant
Mihama nuclear power plant is a nuclear power station in Japan with 1 operating unit totalling 826 MW gross. The site has 3 units on record in total.
Units
| Unit | Status | Type | Model | Gross MW | Online |
|---|---|---|---|---|---|
| Unit 3 | PWR | M (3-loop) | 826 | 1976 | |
| Unit 1 | Retired | PWR | WH 2LP | 340 | 1970 |
| Unit 2 | Retired | PWR | M (2-loop) | 500 | 1972 |
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.
Mihama nuclear power plant 3
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | Mitsubishi 3-loop |
| Size class | Large |
| Gross capacity | 826MW |
| Net capacity | 780MW |
| Thermal output | 2,440MWt |
| Enrichment | 3–5% U-235 |
| NSSS vendor | Mitsubishi Heavy Industries |
| Planned retirement | 2036planned, not actual |
| Owner | Kansai Electric Power Co100% |
| Operator | Kansai Electric Power |
| Construction start | 7 Aug 1972 |
|---|---|
| First criticality | 28 Jan 1976 |
| Grid connection | 19 Feb 1976 |
| Commercial operation | 1 Dec 1976 |
Mihama nuclear power plant 1 Retired
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | Westinghouse 2-loop |
| Size class | Large |
| Gross capacity | 340MW |
| Net capacity | 320MW |
| Thermal output | 1,031MWt |
| Enrichment | 3–5% U-235 |
| NSSS vendor | Westinghouse Electric Company |
| Owner | Kansai Electric Power Co100% |
| Operator | Kansai Electric Power |
| Construction start | 1 Feb 1967 |
|---|---|
| First criticality | 29 Jul 1970 |
| Grid connection | 8 Aug 1970 |
| Commercial operation | 28 Nov 1970 |
| Permanent shutdown | 27 Apr 2015 |
Mihama nuclear power plant 2 Retired
| Reactor type | Pressurised water reactor (PWR) |
|---|---|
| Model | Mitsubishi 2-loop |
| Size class | Large |
| Gross capacity | 500MW |
| Net capacity | 470MW |
| Thermal output | 1,456MWt |
| Enrichment | 3–5% U-235 |
| NSSS vendor | Mitsubishi Heavy Industries |
| Owner | Kansai Electric Power Co100% |
| Operator | Kansai Electric Power |
| Construction start | 29 May 1968 |
|---|---|
| First criticality | 10 Apr 1972 |
| Grid connection | 21 Apr 1972 |
| Commercial operation | 25 Jul 1972 |
| Permanent shutdown | 27 Apr 2015 |
Mihama nuclear power plant in context
By gross operating capacity Mihama nuclear power plant is the 7th largest of 9 operating nuclear sites in Japan, holding 6% of the country's operating capacity, and ranks 156th of 172 worldwide.
Its operating unit started up in 1976; the unit is 50.0 years old, older than the median of 35.0 in Japan.
The 3 units with both construction and grid dates on record took 3.5 to 3.9 years (median 3.5) 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 Ohi nuclear power plant (33 km), Takahama nuclear power plant (46 km) and Shimane nuclear power plant (269 km).
The tracker lists a planned retirement year, a forecast and not a decision on record, for 1 operating unit: Unit 3 (2036).
Build time by unit
| Unit | Construction start | Grid connection | Years | Fleet median, same decade |
|---|---|---|---|---|
| Unit 1 | 1967 | 1970 | 3.5 | 5.4 (1970s) |
| Unit 2 | 1968 | 1972 | 3.9 | 5.4 (1970s) |
| Unit 3 | 1972 | 1976 | 3.5 | 5.4 (1970s) |
Nearest tracked nuclear sites
| Site | Country | Distance | Operating GW gross |
|---|---|---|---|
| Ohi nuclear power plant | Japan | 33 km | 2.4 |
| Takahama nuclear power plant | Japan | 46 km | 3.4 |
| Shimane nuclear power plant | Japan | 269 km | 0.8 |
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 Mihama 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 | Fukui, Japan |
|---|---|
| Coordinates | 35.7024, 135.9634 |
| Elevation | about 15 mabove sea level |
| Setting | On the sea coast, 0.1 km from the water |
| Region | Eastern Asia |
| Units by status | Operating: 1 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 | Kansai Electric Power Co |
|---|---|
| Operators | Kansai Electric Power |
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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