Annual outages completed - normal electricity production resumed in Olkiluoto

9.6.2016

The annual outages of 2016 ended on Thursday, 9 June, at 02:17, with the completion of the outage at the Olkiluoto 1 plant unit. This year OL1 underwent more extensive maintenance work, while OL2 was in turn for a refuelling outage. The total duration of the outages was one month.

At Olkiluoto 1, the key works carried out during the maintenance outage included replacement of one main circulation pump and the associated frequency converter, renewal of the neutron flux calibration system, replacement of low-voltage switchgears as well as modernisation in one sub-system of the heating system that contributes to residual heat removal. A containment leak-tightness test was also carried out. In addition to TVO's own personnel, up to about one thousand employees of external contractors were involved in the outage works.

The refuelling outage of OL2 included also maintenance work scheduled for performance once a year, in addition to refuelling. The refuelling outage started on 8 May and lasted for ten days.

All in all, the annual outage period was about five days longer than expected. The schedule was affected e.g. by delays in work carried out on control rod actuators. In all other respects the annual outages were implemented according to plans.

- Our track record in the execution of annual outages has been good over the years. This year the outage programme included also some challenging activities, but we tackled them with a good attitude according to our motto "it's all about the attitude". The thanks for this must primarily go to our professional and committed staff, says Mikko Kosonen, Senior Vice President, Electricity Production.

Olkiluoto nuclear power plant has been modernised over the years through extensive modernisation projects and the annually alternating refuelling and maintenance outages. The maintenance and replacement schedules specified for each device and component are adhered to without fail in the annual outages. Good advance planning is the key to avoid failures of safety-critical equipment and equipment parts and to secure the long operating life of the plant units.

For more information, please contact:
Mikko Kosonen, Senior Vice President, Electricity Production, Tel. +358 2 8381 2100

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