Test production has been completed at the Olkiluoto 3 (OL3) EPR in Finland and the plant has now started regular electricity production, operator Teollisuuden Voima Oyj (TVO) has announced. TVO said the reactor will soon be declared to be in commercial operation.

Olkiluoto 3 (Image: TVO)

OL3 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.

The completion of test production was initially delayed after material that had detached from the steam guide plates was found in the turbine's steam reheater in May, which required inspection and repair work. Later, in October, damage was discovered in the internals of the feedwater pumps located in the plant's turbine island during maintenance and inspection work.

The plant was operated at full capacity for the first time in late-September last year.

TVO announced on 16 April that test production at the plant had been completed and regular electricity production has now started.

"This is a historical day, the benefits that we promised OL3 would bring to the Finnish society are realised," said Marjo Mustonen, TVO Senior Vice President for Electricity Production. "I am proud of all the nuclear professionals involved in the project."

OL3 will produce about 15% of Finland's total electricity consumption, while the Olkiluoto plant as a whole will generate about 30% of the country's electricity.

"The production of Olkiluoto 3 stabilises the price of electricity and plays an important role in the Finnish green transition," said TVO President and CEO Jarmo Tanhua. "The electrification of the society continues and environmentally friendly electricity production is undoubtedly one of the top trump cards that Finland has."

The first annual outage at OL3 is scheduled to take place in March 2024.

The Areva-Siemens consortium constructed the OL3 plant under a fixed-price turnkey contract. Construction began in 2005 but there have been various setbacks and delays.

TVO said the contractual end of the Olkiluoto 3 project will occur "once the analyses from the latest test production phase are completed and TVO is in a position to make appropriate decisions on the acceptance of the plant unit and the start of commercial operation. These decisions will be made in the near future".

The first EPR units came online at Taishan in China, where unit 1 became the first EPR to enter commercial operation in 2018 followed by Taishan 2 in September 2019. In Europe, EPRs are currently under construction in France and the UK: Flamanville 3, currently expected to start up in 2023 with commercial operation in 2024; and two units at Hinkley Point C, currently slated for grid connection in 2027 (unit 1) and 2028 (unit 2).

Researched and written by World Nuclear News