The Olkiluoto 3 ( OL3 ) nuclear plant , operated by the Finnish company Teollisuuden Voima Oyj ( TVO ), recorded a leak of radioactive coolant of approximately 100 cubic meters, during the filling of the reactor pool during its annual shutdown. The incident took place on March 7, 2025, and was due to human error in closing a hatch, which allowed coolant to leak into the containment rooms and the floor drainage system.
Radioactive coolant leak assessment
According to TVO, the leak did not pose a danger to nuclear safety , the environment, or plant workers. Furthermore, OL3’s containment systems are designed to prevent this type of liquid from reaching the outside, allowing radioactive waste to be treated according to established protocols.
As an immediate response, cleaning measures were implemented in the affected areas and new instructions were issued for maintenance personnel. TVO has also launched an internal investigation to identify corrective measures to prevent similar incidents in the future.
Despite the leak, TVO confirmed that the plant’s annual shutdown continues unabated and is scheduled to begin in early May. During this period, inspections, overhauls, and improvements to the plant’s infrastructure are being carried out to ensure its safe and efficient operation.
The incident has generated attention within the nuclear sector, as Olkiluoto 3 is one of the most advanced EPR reactors in operation. TVO reaffirmed its commitment to safety and transparency, ensuring that the results of the investigation will be used to strengthen safety procedures at the plant.
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Source and photo: TVO
