Fukushima Daini
Twelve kilometres from Daiichi, four reactors hit by the same tsunami reached cold shutdown without a release. It is the control experiment for the accident everyone remembers.
| Date | 2011-03-11 |
|---|---|
| INES rating | 3 Serious incident |
| Facility | power reactor |
| Unit | Fukushima Daini nuclear power plant 1 |
| Reactor type | Boiling water reactor (BWR) |
| Country | Japan |
| Deaths at the time | 0 |
|---|---|
| Acute radiation deaths | not established |
No deaths, no injuries and no significant release.
The same earthquake and tsunami that destroyed Fukushima Daiichi
What happened
The tsunami flooded seawater pumps and knocked out the heat sink for three of the four units. One of the site's external power lines survived, which Daiichi's did not. Staff laid about nine kilometres of cable by hand over three days to restore cooling to the affected units, and all four reached cold shutdown by 15 March.
Consequences
Rated INES 3 for the loss of safety functions rather than for any release. No significant radioactivity escaped. The units never restarted and decommissioning was decided in 2019.
What changed afterwards
Daini is the reason Daiichi is understood as a preventable accident rather than an unsurvivable one. The two sites faced the same earthquake and a comparable wave; the differences were the height of the site, where the emergency generators and switchgear were placed, and whether one external power connection stayed up.
Other accidents
| Accident | INES | Date |
|---|---|---|
| Chernobyl | 7 | 1986-04-26 |
| Fukushima Daiichi | 7 | 2011-03-11 |
| Kyshtym (Mayak) | 6 | 1957-09-29 |
| Chalk River NRX | 5 | 1952-12-12 |
| Windscale Pile 1 fire | 5 | 1957-10-10 |
| Three Mile Island Unit 2 | 5 | 1979-03-28 |
| SL-1 | 4 | 1961-01-03 |
| Lucens | 4 | 1969-01-21 |
| Saint-Laurent A1 fuel melt | 4 | 1969-10-17 |
| Bohunice A1 refuelling accident | 4 | 1977-02-22 |
| Saint-Laurent A2 fuel melt | 4 | 1980-03-13 |
| Tokaimura criticality accident | 4 | 1999-09-30 |
| Browns Ferry cable fire | 3 | 1975-03-22 |
| Greifswald cable fire | 3 | 1975-12-07 |
| Vandellòs I turbine fire | 3 | 1989-10-19 |
| Tomsk-7 reprocessing explosion | 3 | 1993-04-06 |
| Davis-Besse vessel head corrosion | 3 | 2002-03-06 |
| Paks fuel cleaning accident | 3 | 2003-04-10 |
Sources
- World Nuclear Association, Fukushima Daiichi Accident · retrieved 2026-09-07
How these sources are used, including the corrections applied on top of them and what is deliberately left blank · download the underlying data