Olkiluoto 3 nuclear reactor experiences coolant leak during maintenance
A leak of approximately 100 cubic meters of radioactive coolant occurred at Finland’s Olkiluoto 3 nuclear reactor, the largest in Europe, operator TVO confirmed on Monday. The company assured that the incident posed no safety risk to personnel or the environment.
Leak occurred during scheduled maintenance
The leakage took place on Friday during the reactor’s annual maintenance outage, occurring “in connection with the filling of the reactor pool,” TVO stated.
“The coolant flowed into containment rooms closed to the environment and into the floor drain system of the containment. The incident did not pose any risk to the personnel, the environment, or nuclear safety,” TVO said.
Human error to blame for leak
TVO attributed the leak to “a human error,” explaining that a hatch to the pool had not been properly closed during the process.
“The significance of the event to radiation safety was low, in the end, owing to the safety actions taken,” TVO said.
The company further confirmed that the incident would not impact the planned duration of the annual maintenance outage, which is scheduled to last until May.
Olkiluoto 3: A key part of Finland’s energy supply
The next-generation European Pressurized Water Reactor (EPR), constructed by the French-led Areva-Siemens consortium, supplies over 10% of Finland’s electricity.
Like several other EPR projects, the reactor—located on Finland’s southwest coast—faced multiple construction delays and billions of dollars in cost overruns before finally becoming operational.
Olkiluoto 3 remains the largest single nuclear reactor in Europe, while Ukraine’s Zaporizhzhia plant, with six reactors, holds the title of the largest nuclear plant on the continent.
