Corrosion: review of the nuclear fleet in progress, too early to say if shutdowns will be necessary, says ASN

In France, five nuclear reactors are shut down due to corrosion problems. EDF is reviewing all the fleet until the end of the month to ensure that other reactors are not affected.

EDF is reviewing until the end of the month l the entire French nuclear fleet looking for new corrosion problems, the Nuclear Safety Authority (ASN) said on Friday, which does not know at this stage whether new reactor shutdowns will be necessary in the event of suspicion.

“EDF today initiated the re-examination of all the checks that had been carried out in the past and this for all the reactors of the park”, declared Julien Collet, deputy director general of the ASN.

Five unscheduled stops

Currently, of the 56 reactors in the French nuclear fleet, five are shut down due to corrosion problems on one system of security. Problems identified for four of them and suspected for the fifth. These unplanned shutdowns increase the tension a little more on the security of electricity supply this winter in France, when the availability of the fleet is already low.

The fault on this security system originally concerned the family of the most powerful (1.450 MW) and recent EDF reactors. But it has since been seen on a less powerful reactor (1.300 MW), that of Penly 1 (Seine-Maritime). In France, there are reactors of 1.300 MW, of which are of the exact same generation (or level) as that of Penly.

At this stage, it is a documentary work consisting of re-examining the results of past checks in search of the corrosion problem. “This is work that is in progress and should continue until the end of the month. On this basis, EDF will propose to ASN a program for monitoring the reactors in the fleet”, explained Julien Collet.

Will the reactors have to be shut down if a suspicion of corrosion appears during the documentary examination? “It will depend on the elements that will come out of this review and also on the understanding that we have of the phenomena”, he replied.

“Checks could be made, perhaps over the course of the normal shutdown of the reactors, but perhaps a certain number of them will have to be done in advance. This is something that remains to be determined”, he pointed out. “This is a phenomenon that was not expected for this type of steel at this location and the causes of these defects are not well understood today, so there is a expert work which is in progress”, he underlined.

Because of these shutdowns, EDF had to revise its estimate of nuclear production in 202201060347, descendant of 330/450 TWh at 300/300.