The maintenance outage planned for Olkiluoto 1 is scheduled to start on 18 May. ?The estimated duration of the refuelling outage at OL2 is eight days.

In addition to refuelling, the work list includes various maintenance activities, repairs and tests that are executed once a year. According to plans, OL2 will be restored to electricity generation on 17 May.

OL1 will undergo a longer maintenance outage expected to last about 16 days. The biggest jobs include replacement of the recirculation pump and the associated frequency converter, renewal of the neutron flux calibration system, and modernisation in one sub-system of the heating system that contributes to residual heat removal. A containment leak-tightness test will also be conducted. The annual outage is scheduled to be completed at OL1 on 3 June.

The number of employees of external contractors involved in the annual outages, in addition to TVO’s own personnel, will rise to up to 1,100 people this year.

It’s all about attitude in outages

The alternating refuelling and maintenance outages of the plant units are designed to maintain the Olkiluoto nuclear power plant in good condition at all times, in terms of both production and operability.

Outage preparations are started well in advance, as thorough planning is the only route to the desired end result. The schedule for OL1 contains about 1,300 work activities this year, with a total of 4,000 different work phases. At OL2, the figures are 560 and 1,200, respectively. The execution of the entire outage process will take approximately 200,000 person-hours.

– This year our theme is "It’s all about attitude". We are placing special emphasis on highlighting safety issues. Without attitude and professional pride, we would not be able to carry out the outages according to plans, says Mikko Kosonen, Senior Vice President, Electricity Production.