OL3, the third reactor unit at Olkiluoto Nuclear Power Plant in Eurajoki, Western Finland, was photographed on 9 September 2021. (Heikki Saukkomaa – Lehtikuva)


TWO SCRAMS, or emergency reactor shutdowns, have occurred during commissioning testing of the third reactor unit at Olkiluoto Nuclear Power Plant in Eurajoki, Western Finland, reveals the Radiation and Nuclear Safety Authority (STUK).

The first scram occurred on 14 January and the second on 29 January.

STUK on Monday underscored that all plant systems functioned as intended during both emergency shutdowns, which are a mechanism to ensure the plant does not pose a threat to nuclear safety. The safety significance of the two events, it added, was so low that they could not be placed on the International Nuclear and Radiological Event Scale (INES).

The commissioning tests conducted thus far indicate that the reactor unit is safe, it clarified.

Read more:

Teollisuuden Voima (TVO), the operator of Olkiluoto Nuclear Power Plant, on 3 February announced the start of electricity production by the third unit will be postponed by roughly a month on grounds of development needs detected during the commissioning stage.

The unit is thus expected to start producing electricity at a roughly 25-per-cent capacity in late February instead of late January. Raising the capacity over 30 per cent will require the approval of STUK.

“A need to, for example, implement automation related to the adjustment functions of the plant unit and to conduct additional testing related to the changes was detected during the commissioning phase of OL3,” it said. “The rectifying measures have been initiated, but they will cause a delay in the commissioning schedule.”

The unit is presently scheduled to start electricity production at full capacity in July.

The long-delayed project was originally scheduled for completion in 2009.

Aleksi Teivainen – HT