OL1 & OL2 structure

The OL1 and OL2 power plant units can each be divided into three structural entities: the reactor building, the turbine plant and the auxiliary buildings.

The highest building in both units is the reactor building enclosing the reactor containment, which in turn houses the reactor pressure vessel.

The principal components in the turbine plant are the high-pressure turbine, the four low-pressure turbines, the generator and the condenser.

Besides the reactor building and the turbine plant, there are facilities for the control room and for waste management. The OL1 unit also houses a laboratory shared by the two units. 

Differences between the nuclear power plant units

The two nuclear power plant units at Olkiluoto, which are on stream, Olkiluoto 1 and Olkiluoto 2 (OL1 and OL2), are identical. Both have a boiling water reactor. The third unit currently under construction, Olkiluoto 3 (OL3), is a pressurized water reactor.

Read more about the differences between a boiling water reactor and a pressurized water reactor.