OL3: Successful filling of the plant unit’s cooling water pumping station


On July 31, the water gate between the Gulf of Bothnia, in the Baltic Sea, and the seawater intake structures of Olkiluoto 3 nuclear power plant unit was opened successfully to start the filling operation of the cooling water pumping station, according to the action plan approved by the plant operator, TVO.

This operation is an important pre-requisite for the upcoming commissioning tests to be performed on the service water* and cooling water systems of both the nuclear and conventional islands of the plant unit.

Once the leak tightness of the structures was checked and confirmed, the filling operation was successfully completed on August 1 by reaching equilibrium with sea level after a total filling duration of 7.5 hours.

The pumping station now contains 30.000 m³ of seawater safely isolated from the rest of the plant unit by concrete walls and physical blockings. The water will later supply the plant unit’s cooling systems.

“This important project milestone was successfully achieved thanks to the commitment and smooth cooperation of the multiple operational project teams involved from AREVA, Siemens and TVO”, declared Jean-Pierre Mouroux, OL3 Project Director.


*Sea or spring water directly taken form the natural environment and not having been subject to any kind of preliminary treatment.