OL2, OL1 nuke plants to undergo annual outages this month

Electricity production at the Olkiluoto 2 plant unit (OL2) will be shut down for a refuelling outage on April 6, said the owner of the plant Teollisuuden Voima Oyj (TVO) in a press release on Thursday.

Following the completion of this outage, on 19 April, the service outage for Olkiluoto 1 (OL1) will begin and last until mid-June.

The refuelling outage for OL2, which will begin on Monday, is expected to last for about ten days.

Various annual preventive maintenance tasks, inspections, repairs and tests will be carried out at the plant unit in addition to refuelling.

The plant unit’s power reduction for the annual outage will begin on April 5, when the unit’s output will be reduced to about half to enable the tests carried out at that time.

OL2 is scheduled to resume electricity production on 16 April.

This year, a more extensive service outage lasting about 55 days will take place at OL1.

The long duration of the outage is due to the implementation of several extensive work tasks and plant modifications. The most significant tasks include a repair of the turbine condenser’s front chamber, reactor I&C modernisation, high pressure turbine service, replacement of some electrical penetrations in the containment and a pressure test of the primary circuit.

The annual outage for OL1 will conclude on 13 June.

The OL1 and OL2 plant units alternate between shorter refuelling outages and longer service outages. The number of scheduled tasks determines the length of a service outage.

About 500 tasks are performed during OL2’s refuelling outage, whereas OL1’s annual outage includes approximately 1,350 tasks.

In addition to TVO’s in-house personnel, approximately 1,400 contractor employees participate in the annual outages this spring.

The outage for Olkiluoto 3 (OL3) will take place in September and October, following the plant unit's 18-month operating cycle.

Annual outages are always carefully planned and scheduled, and work is performed in several shifts around the clock.

“Annual outages are a substantial effort, and their success depends on careful planning, strong competences and fluent cooperation between various organisations. They can be compared to a Grand Prix pit stop: work is prepared carefully in advance and then implemented efficiently as one team during the outage,” said Marjo Mustonen, Senior Vice President for Electricity Production of TVO.