Olkiluoto units 1 and 2 - which were first connected to the grid in September 1978 and February 1980, respectively - currently meet 15% of Finland's electricity demand.
In September 2018, the Finnish government approved a 20-year extension to the operating licences of both units. The new licence replaced TVO's then current operating licences, issued in 1998, which were valid until the end of 2018. The two boiling water reactors are currently permitted to operate until the end of 2038.
TVO said it is now considering extending the operating licences by at least a further 10 years.
"Extending the lifespan would support domestic year-round and weather-independent electricity production as well as Finland's and Europe's climate goals," said TVO's Director of Electricity Production, Marjo Mustonen.
The company noted the units have been modernised throughout their service lives by means of annual maintenance and major investments, which means "they remain in excellent operational condition". TVO said about EUR50 million (USD53 million) are invested annually in Olkiluoto 1 and 2.
The investments, it said, have also enabled power uprates of the units from their original capacities of 660 MWe (net) to the current 890 MWe.
In addition to the operating licence extension, TVO said it has also looked at opportunities to further uprate the power of the units. An uprating of 80 MWe is being investigated for both units, increasing power levels from 890 MWe to about 970 MWe. This would mean an annual production increase of 1.2 TWh, TVO noted.
The company said that decisions regarding the licence extensions and power uprates will be made after the completion of the EIA report.
Unit 3 of the Olkiluoto plant attained first criticality on 21 December 2021 and was connected to the grid on 12 March 2022. The EPR, a 1600 MWe pressurised water reactor, then entered a phase of test production during which some 3300 tests were conducted and more than 9000 test reports collated. It entered commercial operation on 1 May this year. OL3 produces about 15% of Finland's total electricity consumption.
