The first outage of the 1600 MWe EPR at unit 3 of Finland’s Olkiluoto NPP (OL3) will be extended by a week. Initially the outage was supposed to end on 8 April, but owner operator Teollisuuden Voima Oyj (TVO) says the outage will now be completed by 20 April. Announcing a previous delay to 15 April, TVO said the shutdown of the unit and preparation for the fuel unloading had taken more time than planned. TVO now says more time than was planned is needed for the plant unit’s fuel inspections.

“Earlier, we reported slower-than-expected cooling of components and some technical problems that caused a week-long extension to annual maintenance. A five-day extension is now needed, particularly for extended fuel inspections. When the fuel is transferred back to the reactor at the end of the annual maintenance, we still want to ensure its purity so that the bulk parts do not end up in the process.” OL3’s annual maintenance started on 2 March and the rest of the work has progressed well, TVO noted. About 1,100 external professionals participated in the maintenance.

OL3 began regular electricity production in April 2023 following the completion of trial operation. Construction of OL3 began in 2005 and various setbacks and delays mean the plant is some 14 years behind the original schedule and significantly over budget. OL3’s final price tag is put at some $11bn ($12bn), some three times what was initially estimated. OL3 attained first criticality in December 2021 and was connected to the grid on in March 2022. The EPR was operated at full capacity for the first time in late September 2022. However, cracks were identified in the impellers of the feedwater pumps located in the turbine island, causing further delays.


Image: Olkiluoto 3 (courtesy of TVO)