Which of Japan's reactors are running?
On 16 Sep 2026 the regulator lists 11 of Japan's reactors as in operation (10.6 GW gross). 22 more are built and suspended (22.5 GW gross), and 26 are being decommissioned. Our fleet record counts 15 units as operating, so 4 of them are suspended on the regulator's list.
A snapshot of the Nuclear Regulation Authority's own list, not a live feed: the list was last updated on 16 Sep 2026, and we last compared it with the NRA's page on 28 Oct 2026 and found it unchanged. "Suspended" is the regulator's word and does not say why a unit is idle: a unit stopped for a periodic inspection and one idle since 2011 are both suspended. The NRA updates its list on its own schedule, so a unit that has started or stopped since the date above may not show here yet.
In operation
| Unit | Type | Gross MW | Started |
|---|---|---|---|
| Genkai 4 | PWR | 1,180 | 1997 |
| Ikata 3 | PWR | 890 | 1994 |
| Kashiwazaki Kariwa 6 | BWR | 1,356 | 2026 |
| Mihama 3 | PWR | 826 | 1976 |
| Ohi 4 | PWR | 1,180 | 1993 |
| Sendai 1 | PWR | 890 | 1984 |
| Sendai 2 | PWR | 890 | 1985 |
| Shimane 2 | BWR | 820 | 2024 |
| Takahama 1 | PWR | 826 | 1974 |
| Takahama 2 | PWR | 826 | 1975 |
| Takahama 4 | PWR | 870 | 1985 |
Built and suspended
Units that exist and are not running on the regulator's list. Our fleet record's own status is shown beside each: where it says operating, our record counts the unit as operating while the regulator lists it as stopped on 16 Sep 2026.
| Unit | Type | Gross MW | Started | Our fleet record |
|---|---|---|---|---|
| Genkai 3 | PWR | 1,180 | 1994 | Operating |
| Hamaoka 3 | BWR | 1,100 | 1987 | Mothballed |
| Hamaoka 4 | BWR | 1,137 | 1993 | Mothballed |
| Hamaoka 5 | BWR | 1,380 | 2005 | Mothballed |
| Higashidori (Tohoku) 1 | BWR | 1,100 | 2005 | Mothballed |
| Kashiwazaki Kariwa 1 | BWR | 1,100 | 1985 | Mothballed |
| Kashiwazaki Kariwa 2 | BWR | 1,100 | 1990 | Mothballed |
| Kashiwazaki Kariwa 3 | BWR | 1,100 | 1993 | Mothballed |
| Kashiwazaki Kariwa 4 | BWR | 1,100 | 1994 | Mothballed |
| Kashiwazaki Kariwa 5 | BWR | 1,100 | 1990 | Mothballed |
| Kashiwazaki Kariwa 7 | BWR | 1,356 | 1997 | Mothballed |
| Ohi 3 | PWR | 1,180 | 1991 | Operating |
| Onagawa 2 | BWR | 825 | 2024 | Operating |
| Onagawa 3 | BWR | 825 | 2002 | Mothballed |
| Shika 1 | BWR | 540 | 1993 | Mothballed |
| Shika 2 | BWR | 1,206 | 2006 | Mothballed |
| Takahama 3 | PWR | 870 | 1985 | Operating |
| Tokai 2 | BWR | 1,100 | 1978 | Mothballed |
| Tomari 1 | PWR | 579 | 1989 | Mothballed |
| Tomari 2 | PWR | 579 | 1991 | Mothballed |
| Tomari 3 | PWR | 912 | 2009 | Mothballed |
| Tsuruga 2 | PWR | 1,160 | 1987 | Mothballed |
Where our record and the regulator differ
Our fleet record (the Global Nuclear Power Tracker) calls Onagawa 2, Ohi 3, Takahama 3, Genkai 3 operating, and the regulator lists them as suspended on 16 Sep 2026. The two answer different questions: the fleet record gives a unit's standing status, while the regulator's list says what is running on its date. The gap closes when a stopped unit resumes.
These have all run since the 2011 shutdown: Onagawa 2 resumed in 2024, Ohi 3 resumed in 2018, Takahama 3 resumed in 2016, Genkai 3 resumed in 2018 (World Nuclear Association, updated 22 September 2026). That the regulator lists them as suspended on 16 Sep 2026 therefore most likely means an outage or inspection on that date, not a unit that has stopped for good. We have no dated source for why each was stopped.
Being decommissioned
26 units at 13 plants: Fugen, Fukushima Daiichi, Fukushima Daini, Genkai, Hamaoka, Ikata, Mihama, Monju, Ohi, Onagawa, Shimane, Tokai, Tsuruga. These are permanently shut down and are not expected to restart; see each unit's page for its shutdown date.
This page does not say how close a suspended unit is to restarting. The review and approval stages for each unit are published elsewhere; the Japan Atomic Industrial Forum keeps a monthly status table (as of 7 August 2026) with outage start dates, review applications and approvals for each unit.
Sources
- Nuclear Regulation Authority, Present States of Operation, last updated 16 Sep 2026 , Government of Japan Standard Terms of Use v2.0, compatible with CC BY 4.0 · retrieved 2026-10-28 · edited by NuclearChain: plant-and-unit rows matched to our reactor records and the NRA wording reduced to three states; not a Government of Japan publication
- Capacity, type and start year: Global Nuclear Power Tracker, Global Energy Monitor, August 2026 release , CC BY 4.0
How these sources are used, including the corrections applied on top of them and what is deliberately left blank · download the underlying data