Image: Jari Pelkonen / Yle

The startup date for the Olkiluoto 3 (OL3) nuclear reactor on Finland's southwest coast has been pushed back again. Plant owner Teollisuuden Voima (TVO) said on Thursday that it had been informed of the new schedule by the main supplier, the Areva-Siemens Consortium.

The supplier now says that fuel will be loaded into the reactor next summer ahead of grid connection in November 2020. Regular electricity production would start in March 2021, instead of September 2020 as most recently announced.

Faulty components found

TVO says the latest delays are due to slow progress in system testing and shortcomings in spare part deliveries. For instance auxiliary diesel generators were found to have faulty components.

"Because of numerous delays we have to do maintenance to equipment and components already installed to ensure fluent start-up and continuous operation. The manufacturing and deliveries of the spare parts take time," OL3 Project Director Jouni Silvennoinen said in a TVO statement.

Construction work on OL3 started nearly 15 years ago. According to the original timetable, it was to have gone online in 2009. Since then there have been many delays, lawsuits and massive cost overruns.

With a total cost estimate of at least 8.5 billion euros, it has been described as the second-most expensive building in human history, behind a hotel complex in Mecca.

Construction of the original atomic power station began in 1973. The first unit began commercial operations six years later, becoming the country's second reactor after one in Loviisa.

The Fennovoima consortium hopes to build Finland's first entirely new nuclear plant since the 1970s in Pyhäjoki, near Raahe. That project too has been beset by delays and is yet to receive a construction permit.