Alarm in Finland: details of the leak at the EU's most powerful nuclear reactor

On Friday, March 7, the Olkiluoto 3 (OL3) EPR nuclear reactor in Finland, the most powerful operating in Europe, leaked 100 m3 of radioactive coolant. EADaily reported the first information received from the country in an earlier publication.

But the Finnish company TVO, which operates this French-designed power plant, has already announced that the incident "does not pose a risk." According to the AFP news agency, the leak occurred during the annual maintenance "when filling the reactor pool."

"The coolant has leaked into the sealed insulation rooms and into the soil drainage system in the insulation casing," TVO added.

"The incident did not pose any danger to personnel, the environment or nuclear safety," the company said.

According to an official statement, the leak occurred "due to human error: the pool hatch was not closed properly."

"The threat of this event to the general radiation protection ultimately turned out to be low due to the security measures taken," the Finnish operator also said.

The maintenance schedule has not changed, its completion is scheduled for May. But TVO still "launched an investigation into the causes of the incident and will subsequently submit a report" to the Finnish Nuclear Safety Authority (STUK), in particular, "on measures aimed at preventing its recurrence." The department itself informed about this.

OL3 is the most powerful operating nuclear reactor in Europe, providing 14% of Finland's electricity. Like other ERP construction sites, it was marked by countless delays and huge cost overruns, which was one of the main reasons for the restructuring of the developer — the French Areva group, later renamed Orano.