Cattenom nuclear plant ignored ventilation failure for six hours: investigation launched

French nuclear regulators have launched a probe into a safety violation incident at the Cattenom nuclear power plant, located near the border with Luxembourg. On 3 June, the site was found to have a blocked valve in the ventilation system of the spent fuel building, one of the key elements of emergency safety.

According to regulations, in the event of such a failure, operation should be shut down within one hour. However, the technicians continued to work for almost six hours, and in two separate sessions - a direct violation of the current rules for operating nuclear facilities.

Operator EDF denied the immediate threat, saying the situation was under control. Nevertheless, on 10 June, the French Nuclear Safety Agency (ASN) was officially notified of the incident, and the incident was classified as Level 1 on the International Nuclear Event Scale (INES) - the lowest level, but still indicating a deviation from safe operation.

The ventilation system in a fuel storage building is critical: it regulates temperature and prevents the accumulation of radioactive gases. A blocked valve could potentially disrupt air circulation in an emergency. Therefore, even if there was no direct threat at the time of detection, non-compliance raises questions about corporate safety culture and staff supervision.

The Cattenom plant has long been a concern for its neighbours - especially Luxembourg, which has no nuclear power of its own but is in close proximity to the facility. Any failure - even a minimal one - is viewed through the prism of potential cross-border risk.

French nuclear regulators will investigate why there was such a long deviation from procedure and what actions Électricité de France (EDF) will take to address such failures in the future. This is not the first time that discipline and compliance issues at EDF facilities have been the subject of public criticism.