Long-Delayed EPR Nuclear Plants Face Further Holdups

Teollisuuden Voima Oyj (TVO), owner of the Olkiluoto 3 EPR (European Pressurized Water Reactor) nuclear unit that is under construction in Finland, has said fuel will not be loaded in the reactor before the end of August, while it awaits completion of a schedule review being conducted by the construction consortium. Meanwhile, EDF, which is building an EPR at its Flamanville site in France, was informed by the French nuclear safety regulator, Autoriti(C) de Sireti(C) Nucli(C)aire (ASN), that eight welds in the main steam transfer pipes that penetrate the two walls of the containment must be repaired before the reactor is commissioned.

Setbacks have plagued the two under-construction units. Olkiluoto 3 was ordered as a turnkey delivery from a consortium formed by AREVA GmbH, AREVA NP SAS, and Siemens AG. The plant was originally expected to commence commercial operation at the end of April 2009. However, according to the latest schedule update by the plant supplier, regular production was planned to begin in January 2020. Now, it appears that timeline won't be met.

In April, TVO said that work during the first quarter of the year at Olkiluoto 3 had not progressed according to the updated schedule issued by the plant supplier in November 2018. Last week, it said a new schedule review would be completed in July rather than as expected in June.

TVO announced some good news in May, however. It said vibration detected in the cooling circuit's pressurizer surge line during hot functional testing in the first half of 2018 would be eliminated using "liquid absorbers." The company reported that the bitumen material used in the absorbers had been approved by the Finnish Radiation and Nuclear Authority (STUK). Other positive developments in roughly the past year include completion of hot functional testing in May 2018, STUK granting licenses to operating personnel in December 2018, and the Finnish government granting an operating license for the EPR in March 2019.

At the Flamanville site-where work began in December 2007 and the unit was originally expected to start commercial operation in 2013-weld quality deviations have been the most-recent problem. On Dec. 3, 2018, EDF submitted to ASN a technical file presenting the procedures for repairing and upgrading the main secondary circuit welds, which had showed deficiencies with respect to break preclusion requirements. The company also submitted the specific justification method for the eight welds located in the reactor containment building structure.

Earlier this month, EDF reportedly asked ASN about the possibility of repairing the welds in 2024, after the unit was commissioned. While ASN said that would be technically feasible, it would pose a number of problems, notably with regard to demonstrating the safety of the reactor during the interim period.

In a statement, EDF said it "is currently analysing the impact of this decision on the Flamanville EPR schedule and cost, and, in the upcoming weeks, it will give a detailed update on the next steps in the project."

-Aaron Larson is POWER's executive editor (@AaronL_Power, @POWERmagazine).

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