EDF has reported three “significant safety events” involving equipment at the Flamanville EPR reactor since its commissioning in early May.
These anomalies were linked to non-compliance with operating rules but had no consequences for “people and the environment,” according to ASN, the nuclear safety watchdog.
INES Level 1 Classification
“Since the commissioning of the reactor (on May 8th), the operator has reported several significant events for safety, three of which were classified as Level 1 on the INES scale,” ASN stated on Tuesday in an information letter on its website.
The INES scale has eight levels, ranging from deviation (0) to major accident (7). According to the nuclear watchdog, these incidents did not “have any consequences on people and the environment.”
Temporary Suspension of Start-Up Operations
However, they led EDF to “temporarily suspend the reactor’s start-up operations to analyze the root causes of the reported events, implement corrective actions, and secure future activities for the continuation of the reactor’s start-up.”
EDF’s Response
When contacted, EDF indicated that “downtimes” were observed to “take into account the lessons learned from these events,” without affecting the reactor’s start-up schedule.
“The grid connection is still planned for the summer,” said an EDF spokesperson. This “coupling” to the grid will occur after the first nuclear reaction expected in July, according to EDF, and will mark the start of the reactor’s electricity production at 25% of its capacity.
Nature of the Incidents
“These events are anomalies with no real impact on the safety of the facilities. They concern the non-compliance with a requirement or specification outlined in the general operating rules,” EDF emphasized in an information note, detailing the nature of these incidents on safety equipment, which occurred between May 15th and June 3rd.
Latest Incident and Delayed Detection
The most recent incident involved the “late detection of the non-closure of a valve between the safety injection system and the intermediate cooling system,” according to EDF. Although an alarm associated with this anomaly was triggered, it was not immediately addressed. “The deviation was detected two hours later by the operations manager, and the installation was brought back into compliance,” according to ASN.
86 Level 1 Events Across the Fleet in 2023
In addition to these three Level 1 incidents, there were seven other events classified as Level 0 deviations.
The Flamanville EPR, the most powerful reactor (1,600 MW) in the current nuclear fleet of 57, entered service on May 8th, with a 12-year delay compared to the expected schedule.
In 2023, ASN received 1,098 reports of significant safety events, 86 of which were classified as Level 1 on the scale.