The third reactor of Olkiluoto Nuclear Power Plant in Eurajoki, western Finland, on 5 October 2022. Teollisuuden Voima (TVO), the operator of the power plant, said this week it has yet to determine the cause of the cracks detected in several feedwater pumps at the reactor unit. (Olivier Morin – AFP / Lehtikuva)


TEOLLISUUDEN VOIMA (TVO) is continuing to investigate the damage detected in the feedwater pumps of the third reactor of Olkiluoto Nuclear Power Plant.

TVO on Monday stated that it is unable to set a date for resuming the test programme because of unanswered questions about the cracks detected in the internals of all four feedwater pumps on the turbine island during routine inspections and maintenance in October.

The company estimated after detecting the damage that test use of the reactor would continue at full capacity on 13 November.

“The cause and failure mechanism of the damage are still open. We also don’t know the possible effects on the schedule,” Johanna Aho, the director of communications at TVO, stated to Helsingin Sanomat on Monday.

TVO highlighted in its press release that the feedwater pumps were supplied by a proven pump supplier.

The damage prompted the company to push back its timetable for the start of commercial electricity generation at the reactor unit to 27 December. Test use of the reactor unit began earlier this year, with the unit reaching its full capacity of 1,600 megawatts for the first time on 30 September.

Aho on Monday stated to the newspaper that the test programme was moving forward smoothly and that the company had moved on to full-capacity testing just before the scheduled maintenance break during which the cracks were detected. The unit still has to undergo roughly a dozen tests at full capacity.

Helsingin Sanomat pointed out that tests at lower capacity are usually more challenging because plants have been designed to operate at full capacity.

Aleksi Teivainen – HT