TVO had originally planned to return to test production after maintenance and repairs on 20 February, but now expects the plant being reconnected to the grid on 25 February.
On 11 February TVO said inspections of the turbine island had been completed. However, during the startup a valve fault was identified, which will need to be repaired before the test production phase resumes.
Last month TVO said it would install “more robust” impellers in all four of the 1,600-MW EPR plant plant’s feedwater pumps with electricity production to resume immediately following the work.
After the installation of the new impellers, electricity production wills continue with a demonstration phase, during which the plant will produce electricity to the grid at mainly full power.
The delays to test production and commercial operation have been caused by an investigation into damage in Olkiluoto-3’s feedwater pumps.
Project Has Seen Number Of Delays
Cracks in the impellers of the feedwater pumps, discovered in October, were most likely caused by the test production process, during which the pumps were deliberately operated outside the normal range, TVO said.
The Olkiluoto-3 project has seen a number of delays. In April TVO announced that regular electricity production had been pushed back from the end of July 2022 to September 2022 because of an inspection and possible repairs related to the cooling system of the plant’s generator.
The company then said test production had been interrupted for more than a month causing a further delay in the start of regular electricity production. That delay was caused by “foreign material issues” in the turbine’s steam reheater.
In May, foreign material detached from the steam guide plates was found in the turbine’s steam reheater, which needs inspection and repair work.
During testing in September, Olkiluoto-3’s output reached full capacity of 1,600 MW for the first time, making it the most powerful electricity production facility in Europe and the third-most powerful globally, according to TVO.