Olkiluoto-3 test production phase resumes after repair work

Teollisuuden Voima Oyj (TVO), owner and operator of the Olkiluoto nuclear power plant in Finland, has resumed Olkiluoto-3's test production phase, following completion of maintenance and repair work at the new reactor's turbine island, the company announced this week.

TVO had announced in June a delay to the unit's commercial start of some three months-from September to December-after material that had detached from the steam guide plates was found in the turbine's steam reheater in May, necessitating repair work and a halt to testing.

Nearing the finish line: In its August 8 announcement, TVO said the unit's test production phase is now at a 60 percent power level, roughly equal to an output of 850 MW.

"According to the test schedule given by the plant supplier, test operation will proceed to 80 percent power level tests after mid-August," the announcement continued. "With a power output of approximately 1,300 MW at that power level, the Olkiluoto-3 plant unit will be bigger than any other Finnish power plant unit. The first full-power tests where the power unit will produce electricity with an output of about 1,600 MW are scheduled in September. . . . The test production phase of the plant unit will be completed in December 2022, allowing Olkiluoto-3 to move forward to regular and normal electricity production."

Background: Olkiluoto-3 was connected to Finland's power grid on March 12 of this year. At the time, TVO projected that commercial operation would begin in late July. In April, however, the company announced a postponement to September, due to inspection and repair needs regarding the cooling system of the unit's generator.

Europe's first EPR, the Framatome-supplied, 1,600-MWe Generation III+ Unit 3 is also the first new Finnish reactor in four decades and one of only three new reactors in Europe in the past 15 years. (Romania's Cernavoda-2 began supplying electricity to the grid in August 2007, and Belarus's Belarusian-1 in November 2020.) Once up and running, Olkiluoto-3 is expected to produce approximately 14 percent of Finland's electricity demand.

Located in western Finland, Olkiluoto also houses two 890-MWe boiling water reactors. Units 1 and 2 began commercial operation in October 1979 and July 1982, respectively.