Saint-Laurent A1 fuel melt
Fifty kilograms of uranium melted during refuelling, eleven years before the same station did something similar again. France's two worst reactor accidents happened at the same site.
| Date | 1969-10-17 |
|---|---|
| INES rating | 4 Accident with local consequences
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 | Saint-Laurent nuclear power plant A-1 |
| Reactor type | Gas-cooled reactor (GCR) |
| Country | France |
| Deaths at the time | 0 |
|---|---|
| Acute radiation deaths | not established |
No deaths or injuries. Contamination stayed inside the containment.
A loading error during on-load refuelling
What happened
The refuelling machine loaded fuel into a channel that had not been correctly configured, restricting coolant flow. Five fuel elements melted. The reactor was shut down for about a year.
Consequences
Contamination was confined to the reactor building. The unit returned to service and ran until 1990.
What changed afterwards
The precedent for the 1980 accident at Saint-Laurent A2, which had a different immediate cause and the same outcome, a fuel melt in a gas-cooled reactor being refuelled on load. Two events of the same kind at one station is the reason this design family's refuelling arrangements are studied as a case in themselves.
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 |
| 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 |
| Fukushima Daini | 3 | 2011-03-11 |
Sources
- International Atomic Energy Agency INIS, Nuclear incidents and accidents at Saint-Laurent-des-Eaux · 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