The issue of foreign material in the steam reheater of the Olkiluoto 3 EPR's turbine has delayed the start of regular electricity generation by a further three months, operator Teollisuuden Voima Oyj (TVO) has announced.

The Olkiluoto 3 EPR (Image: TVO)

Material that had detached from the steam guide plates was found in the turbine's steam reheater in May this year, which requires inspection and repair work, TVO said. According to investigations from the plant supplier, this repair work will last until the end of July.

The company noted that OL3's test production programme and electricity production can only be continued after the completion of the repair work. Additional time has been reserved in the schedule for the unit's upcoming tests and their analyses based on previous experiences from the test production phase.

"The test production phase will be completed in December 2022, which is when the plant unit's regular electricity production starts," TVO said. Regular electricity production at the EPR unit had previously been expected to begin in September.

The Areva-Siemens consortium constructed the OL3 plant under a fixed-price turnkey contract. They have joint liability for the contractual obligations until the end of the guarantee period of the unit. Construction of Olkiluoto 3 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 last year and was connected to the grid on 12 March. At that time, TVO said a test production phase, lasting about four months, would follow during which OL3's power output will be gradually increased to 100%.

Once regular electricity production has started, OL3 will produce about 14% of Finland's total electricity consumption.

Researched and written by World Nuclear News