TVO completes Final Takeover of Olkiluoto 3

Friday, 20 June 2025

Marjo Mustonen, TVO Senior Vice President for Electricity Production, said Olkiluoto 3 (OL3) had "operated reliably during the first two years. The annual outage this spring, the second one at the unit, was also completed successfully. The Final Takeover of OL3 was based on the fulfilment of the terms and conditions laid down in the Plant Supply Contract, but the many benefits we promised OL3 would bring to society have been realised already since 2023".

TVO said that the new EPR unit, a 1600 MWe pressurised water reactor, had helped make Finland nearly self-sufficient in electricity and "contributes to the stability of the electricity price, and as Finland's greatest climate act, also accelerates the clean transition towards a carbon-neutral society".

The Areva-Siemens consortium constructed the OL3 plant under a fixed-price turnkey contract. Construction began in 2005, with completion of the reactor originally scheduled for 2009, but the project has had various delays and setbacks. OL3 attained first criticality on 21 December 2021 and was connected to the grid on 12 March 2022 before entering commercial operation the following May.

TVO issued an acceptance certificate to the Areva-Siemens consortium for the Olkiluoto 3 EPR in April 2023. They had joint liability for the contractual obligations until the end of the two-year warranty period of the unit, which is when the final acceptance of the plant unit took place.

TVO is 27% owned by Fortum and 57% owned by Pohjolan Voima Oy (the major shareholders of which are pulp and paper manufacturers UPM Oyj and Stora Enso Oyj). Owners take their shares of electricity at cost, with any unwanted portion being sold by them into the Nordic market. This means that output is effectively contracted to each owner over the life of the plant. The private owners are mostly heavy industry with a high demand for base-load power, and hence low costs are critical for them.

The French Government Shareholding Agency (Incarner l'État actionnaire) called it a "historic moment for the French nuclear industry, the first commercially operated EPR in Europe, has now been officially handed over".

In a Linkedin post it added: "This final takeover marks a major milestone for Areva, whose activities were refocused on the completion of the OL3 reactor after the restructuring of the French nuclear sector in 2015. It is also a significant step for France, whose Government is the reference shareholder of Areva and a key supporter of the French nuclear industry. Despite the many challenges encountered since the project's kick-off, the commitment of the Areva and Siemens teams, supported by the expertise of Framatome and EDF, enabled the successful completion ... the final delivery of the plant to our Finnish partner closes a major chapter in the history of the French nuclear sector."

"The collective experience gained from this project will directly contribute to the development of the EPR technology, which remains a strategic priority for France and its industry."

Finland has five operable reactors - two at Loviisa and three at Olkiluoto - providing about a third of its electricity. The world's first operational EPRs were China's Taishan 1 in 2018 and Taishan 2 in 2019. Flamanville 3 in France was connected to the grid in December 2024 and two more EPRs are under construction at Hinkley Point C in the UK, with two more planned at Sizewell C.