Low-confidence record: sources are thin or conflict. Figures below are the best available public statements, not confirmed facts.
Tohoku Electric decided in October 2018 to scrap Onagawa 1, a 524 MWe BWR from 1984 whose cramped containment made post-Fukushima safety upgrades impractical. Its decommissioning plan, filed with the NRA in August 2019, budgets JPY 41.9 billion, of which JPY 30 billion is for dismantling.
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Current state
| Status | Active dismantling |
| Country | Japan |
| Location | Onagawa, Miyagi Prefecture |
| Site | Onagawa |
| Units | Unit 1 |
| Unit count | 1 |
| Reactor types | BWR |
| Owner / licensee | Tohoku Electric Power |
| Strategy | Immediate dismantling |
| Final shutdown | 2018 |
| Cost estimate | JPY 41.9bn (as of 2019-08) |
| Notable issue | Closest plant to the 2011 quake epicentre; survived with a turbine-building fire. |
Notes
final shutdown = year of retirement decision. Plan approval and current stage of work not confirmed in the sources reviewed.
Timeline
- 1984 — Onagawa 1 began operating. (source)
- 2018-10 — Tohoku announced Onagawa 1 would be decommissioned. (source)
- 2019-08-02 — Tohoku applied to the NRA for approval of its decommissioning plan. (source)
The timeline is append-only: corrections are added as new entries. Stated targets appear in the current-state table, never as milestones.
Related sites
- Biblis Nuclear Power Plant (Units A and B) Active dismantling · Germany
- Brokdorf Nuclear Power Plant (KBR) Active dismantling · Germany
- Brunsbüttel Nuclear Power Plant (KKB) Active dismantling · Germany
- Chinshan Nuclear Power Plant Fuel removal · Taiwan
- Chooz A Active dismantling · France
- Crystal River Unit 3 Site restoration · United States
- Doel Nuclear Power Plant (Units 1-3) Shut down · Belgium
- Dounreay (DFR and PFR fast reactors) Active dismantling · United Kingdom
See all 72 sites in the Nuclear Decommissioning Tracker →
Sources
- Tohoku submits decommissioning plan for Onagawa 1 — World Nuclear News, checked 2026-10-11
- Nuclear Power in Japan — World Nuclear Association, checked 2026-10-11