Tomari 3 is Hokkaido Electric's 866 MWe (net) PWR, Japan's newest power reactor (2009). It won NRA approval in July 2025 and Hokkaido governor consent in December 2025; restart awaits a 19-metre seawall now scheduled for completion in August 2027.
Background: Palisades fuel loading: Holtec restart timeline and what comes next · NRC reactor licensing process, explained
Current state
| Status | Approved |
| Country | Japan |
| Location | Tomari, Hokkaido |
| Plant | Tomari |
| Unit | 3 |
| Operator | Hokkaido Electric Power |
| Reactor type | PWR |
| Net capacity (MWe) | 866 |
| Restart type | Post-Fukushima restart |
| Shut down | 2012-05-05 |
| Restart target | 2027 |
| Years offline | 14.4 |
| Regulator | NRA installation-change permit 2025-07-30 (18th reactor to pass); construction plan and pre-use inspections pending |
| Local consent | Hokkaido governor Naomichi Suzuki consented 2025-12-10 and conveyed acceptance to METI 2025-12-18 |
Notes
restart target '2027' per JAIF ('as early as possible in 2027'); Bloomberg cites a Hokkaido Shimbun report that the utility had aimed for mid-December 2027. A 2022 Sapporo District Court injunction against operating the plant was under appeal as of mid-2025 (WNN).
Timeline
- 2012-05-05 — Tomari 3 stopped for a regular inspection; all three Tomari units have been offline since. (source)
- 2013-07-08 — Hokkaido Electric applied for the NRA conformity review. (source)
- 2025-07-30 — The NRA formally approved Tomari 3 after a 12-year review. (source)
- 2025-12-10 — Hokkaido Governor Naomichi Suzuki announced consent to the restart. (source)
- 2026-07-30 — Hokkaido Electric scheduled completion of the 19.0 m seawall for August 2027. (source)
- 2026-08-18 — A worker died in a gravel silo at the seawall construction site, raising risk of further delay. (source)
The timeline is append-only: corrections are added as new entries. Stated targets appear in the current-state table, never as milestones.
Related units
- Genkai Unit 3 Restarted · Japan
- Genkai Unit 4 Restarted · Japan
- Hamaoka Unit 3 Cancelled · Japan
- Hamaoka Unit 4 Cancelled · Japan
- Higashidori Unit 1 (Tohoku Electric) Under review · Japan
- Ikata Unit 3 Restarted · Japan
- Kashiwazaki-Kariwa Unit 6 Restarted · Japan
- Kashiwazaki-Kariwa Unit 7 Approved · Japan
See all 45 units in the Nuclear Plant Restarts Tracker →
Sources
- Current Status of Nuclear Power Plants in Japan as of August 7, 2026 — Japan Atomic Industrial Forum (JAIF) (primary), checked 2026-10-11
- Nuclear Power in Japan — World Nuclear Association, checked 2026-10-11
- Tomari 3 meets safety requirements, regulator concludes — World Nuclear News, checked 2026-10-11
- Hokkaido governor approves Hokkaido Elec Tomari nuclear power plant restart — Reuters, checked 2026-10-11
- Notice Regarding the Timing of Completion of the Seawall at Tomari Power Station — Hokkaido Electric Power (primary), checked 2026-10-11
- Japanese Nuclear Power Plant Death Threatens to Delay Restart — Bloomberg, checked 2026-10-11
- Japan's Nuclear Power Targets from Impossible (2030) to Hardly Achievable (2040) — Renewable Energy Institute, checked 2026-10-11