On Monday 14 November 2022, the Cattenom nuclear power plant (CNPE), operated by Electricité de France (EDF), confirmed that a level 1 safety event occured on Monday 7 November 2022.
On 7 November, during a round on production unit no. 4, currently in scheduled shutdown, the teams from CNPE observed that the water level in a retention basin was lower than the minimum required by the general operating rules. In the event of an accident, this retention provides an additional reserve of water to be injected into the reactor building for cooling. To do this, a pump ensures the recirculation of water from the retention to the reactor building. The lack of water in the retention could have led to the malfunction of the circulation pump, a system which was required when a deviation is detected.
Immediately after detection, the teams resolved the issue by adding more water to the retention basin.
This unavailability had no real impact on safety, but in an accident situation, the recirculation function could potentially not have performed its functions. Due to its late detection, the Cattenom nuclear power plant declared a significant level 1 safety event, on the International Nuclear and Radiological Event Scale (INES) which has seven levels, to the Nuclear Safety Authority (Autorité de sûreté nucléaire - ASN) on Wednesday 9 November 2022.
