Power generation at OL3 to halt for 50 days due to service outage

The Olkiluoto 3 (OL3) nuclear power plant unit will be disconnected from electricity production for a service outage on Thursday, said the owner of the plant Teollisuuden Voima Oyj (TVO) in a press release on Tuesday.

According to plans, electricity production at the plant unit will resume on 30 October after an outage of about 50 days.

“The first operating cycle of 18 months has been extremely successful for OL3. The fact that there have been no disruptions to production reflects the high availability of the plant and the strong competence of our personnel. The upcoming service outage is an important part of the safe and reliable operation of the plant,” said TVO’s Senior Vice President for Operations, Jukka Vastamäki in a press release.

Some 2,000 service activities are to be carried out during the outage, consisting of a total of about 6,000 work phases. In addition to TVO’s own staff, about 1,000 external partners are involved in the service works.

The most important activities to be implemented during the service outage at OL3 include refuelling and associated inspections, as well as corrective work and inspections on the reactor coolant pumps.

Certain technical issues were detected in the reactor coolant pumps towards the end of the operating cycle, but electricity production could be continued with a reduced power output of about 1,300 MW.

Further important activities include cleaning and inspections of steam generators as well as pressure tests of the turbine process systems. In addition to these, numerous recurring preventive maintenance works, inspections, repairs and tests will be carried out.

All work is carefully planned and scheduled and executed in several shifts 24 hours a day.

“The service outage of OL3 is an extensive and complex undertaking requiring precise planning, high professional skills and seamless cooperation to ensure the successful completion of thousands of work phases. The objective is to implement the work safely and to a high standard, so as to ascertain reliable electricity production at OL3 also during the next 18-month operating cycle,” said Marko Kesti, the Senior Vice Preside for Maintenance at TVO.

The next scheduled service outage at OL3 will take place in the spring of 2028.

The OL1 and OL2 plant units remain in normal production operation.