Fourteen years behind schedule, commercial operation of the 1600 MW Olkiluoto EPR finally got under way on 1 May, the owner/operator Teollisuuden Voima Oyj (TVO) having submitted the provisional takeover certificate to the plant supplier on 20 April. Regular electricity production started on 16 April, with completion of a test production run. The much-delayed plant was constructed by a consortium of Areva GmbH, Areva NP SAS, and Siemens AG, under a fixed-price turnkey contract.

“What a wonderful moment this is”, said Jarmo Tanhua, president and CEO, TVO. ”Olkiluoto 3 is ready and we can follow through on the four promises we made 20 years ago to our shareholders and Finnish society: These promises were to meet increased electricity demand and replace plants to be shut down, to allow Kyoto obligations to be fulfilled, to ensure a stable and predictable price of electricity, and to reduce dependency on imported energy.

The final acceptance of the plant unit will take place on termination of the two-year warranty period, TVO says, and even after that, the plant suppliers’ liabilities under the warranty will remain in force ‘to a certain extent’ for a maximum of eight years beyond that.

During the long project, the attitude of Finland’s public has changed. When the project was launched, nuclear power was supported by about 60% of Finns, says TVO, but at present, “the popularity of nuclear power is at a record level with 83% in favour.”

TVO estimates that the new unit will meet about 14 % of Finland's electricity needs, with all three Olkiluoto reactors together providing some 30 %.

According to the original plan, OL3 was to have been completed in 2009.

But the project, ordered from the Areva-Siemens consortium ran into difficulties quite quickly due to delays in the design work and other issues. These led to a series of lengthy, costly legal disputes.

Some of the problems were owing to the fact that at the time it was a new type of pressurised water reactor, designated EPR for ‘European pressurised water reactor’. OL3 was to have been the world's first EPR, but in the event that title went to China's Taishan 1, which began commercial operations in 2018. Two more EPRs are expected to come online in France (Flamanville) and the United Kingdom (Hinkley Point C) in 2024 and 2027 respectively.