10 Dec 2020 17:48 Press release
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 situation is now stable and the unit in a safe state. There was no radioactive release to the environment.
There is no need for protective measures due to the situation. There is no danger outside the unit and no radioactive release is expected. Iodine tablets shall not be taken, and it is no need for other actions as staying inside. The radiation situation outside the unit is normal.
The abnormal operation occurrence was initiated when the radiation measurement instrumentation inside the unit alarmed for increased radiation levels. The higher levels were detected in spaces where the levels are high even during normal operation. Consequently, there are no workers during operation. The personnel has not been exposed to radiation and there are no personnel injuries.
The containment building was isolated so that the plant and plant environment safety was ensured. Both the power company and STUK started their emergency organisations and activities according to emergency preparation plans. There is no indications of fuel leakage and there are no more abnormal radiation levels at the unit.
The occurrence is an exceptional safety event. The safety systems functioned as designed. Consequently the risks for radiation exposure for personnel and environment was very low.