Greifswald cable fire
A cable fire in a VVER-440 at Greifswald destroyed the power supply to most of the main coolant pumps. It became public only after German reunification.
| Date | 1975-12-07 |
|---|---|
| INES rating | 3 Serious incident
Retrospective. INES was introduced in 1990, so this rating is an attribution made
afterwards rather than an assessment a regulator issued at the time.
|
| Facility | power reactor |
| Unit | Greifswald nuclear power plant 1 |
| Reactor type | Pressurised water reactor (PWR) |
| Country | Germany |
| Deaths at the time | 0 |
|---|---|
| Acute radiation deaths | not established |
No deaths and no release. The event was concealed by the East German authorities.
A short circuit during unauthorised switching, and an incorrectly fitted diode
What happened
An electrician bridging a fuse during unauthorised switching caused a short circuit that started a cable fire. The fire destroyed control and power cables for five of the six main coolant pumps. One pump kept running and the core stayed covered.
Consequences
No radiological release. The unit was repaired and returned to service, and the event was not disclosed outside the German Democratic Republic at the time.
What changed afterwards
A near-identical mechanism to Browns Ferry nine months earlier, on the other side of the Iron Curtain, with the same lesson about redundant cables sharing a route. Neither operator knew what the other had learned, which is the strongest single argument for the international event reporting that INES was later built to serve.
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 |
| 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 |
| Fukushima Daini | 3 | 2011-03-11 |
Sources
- International Atomic Energy Agency INIS, Characterization of the cable fire in Block 1 of the Greifswald nuclear power plant · 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