The unit 2 at Olkiluoto will be shut down to a cold state so that the cause of the fault can be determined- the situation is stable

A severe abnormal disturbance occurred at the Olkiluoto nuclear power plant Unit 2 today at 12.22 that led to reactor shut down. The disturbance was possibly caused by a fault in the purification system for the reactor water. The rise of the radiation levels inside the containment caused a full scale emergency response at STUK and at the Olkiluoto power plants. The situation is now stable and the unit in a safe state. There was no radioactive release to the environment and the workers were not exposed to radiation. STUK's radiation measuring car “HÄRKÄ” will tomorrow make verifying measurements in the near-by area.

The event does not affect the operation of Units 1 and the construction of unit 3 at Olkiluoto. There are two operating units (OL1 and OL2) and one unit under construction at Olkiluoto site.

Unit 2 is facing a shutdown which length at this stage is not known.

“TVO must thoroughly investigate the day's events, as the operator is responsible for the safety of the nuclear power plant. STUK will continue to monitor the situation. The plant will only be started up when safety has been ensured,” says Petteri Tiippana, Director General of the Radiation and Nuclear Safety Authority

Unless there are significant changes during the night, we will inform further in the morning.