Delays in construction of the Flamanville 3 EPR means Fessenheim, France's oldest nuclear power station may continue operation until 2019. Fessenheim's two 880MWe pressurised water reactors have been in operation since 1977 and 1978. A 2017 decree paved the way for closure of Fessenheim as soon as Flamanville 3 reactor became operational.

Former President Francois Hollande had pledged during his election campaign that Fessenheim would retire by 2017. Flamanville 3 was due to enter service this year, but EDF said on 31 May that "quality deviations" on welds in the reactor piping connecting the steam generator and the turbine could delay commissioning until summer 2019.  

In February owner/operator EDF noted that some welds on the Flamanville 3 secondary cooling circuit did not meet specifications. But it added that the issue would not affect safety or the schedule to start up the plant at the end of 2018. However, in April EDF acknowledged that problems with the weldings were worse than initially expected and might impact the reactor’s cost and schedule. The problems were discovered during an initial comprehensive inspection of the plant in March – a regulatory requirement before startup.

EDF then decided to carry out additional checks on the 150 welds in question in order to identify exactly which ones were subject to quality deviations. It also ordered a report into the causes and nature of the deviations, so it could define the necessary corrective actions to be proposed to the French nuclear safety regulator, in order to meet safety requirements.   ASN requested EDF to extend the checks on welds to other systems.

Construction of the 1650MWe EPR began in 2007 and was originally expected to start commercial operation in 2013.  However a series of delays resulted in changes to the schedule. EDF's roadmap for Flamanville 3, drawn up in 2015, put fuel loading and reactor startup at the end of the fourth quarter of 2018. Construction costs for the project were put at  €10.5bn, a significant increase on the July 2011 cost estimate of €8bn.  

Cold functional tests began in December and were completed in January. Testing of the reactor building leak tightness was completed on 3 April. Hot functional tests had been due to start in July but will now be postponed.

EDF said, "As a delay of several months to the startup of the Flamanville 3 EPR reactor is one of the possible outcomes, EDF preparing to continue operating the two reactors at the Fessenheim nuclear power station until the summer of 2019."

Photo: Fessenheim nuclear plant (Credit: EDF)