For the director of the Criirad laboratory, France has not taken enough measure of the seismic risk in the country. The typical shake on which the safety margins are based is only 5.2 while the Monday earthquake was 5.4.
franceinfo: What are we monitoring in a "thorough audit" like the one underway at the Cruas plant?
Bruno Chareyron: The importance after an earthquake is to verify that a whole series of devices that are vital to the safety of the nuclear installation have not been weakened. However, we have known for many years now that in France – and this concerns a large number of reactors – a number of these devices are not seismic standards. For example, in 2017, out of 26 nuclear reactors, anchor failures of certain equipment were highlighted. In the event of an earthquake and uncoupling, this would lead to emergency generators not being able to operate. It was also discovered in 2017 that out of 20 French reactors, in the event of a major earthquake, there would no longer be a possibility of pumping cooling water, the so-called cold source. All that to say that in fact, in France, contrary to what citizens may believe, nuclear power plants are not properly designed or exploited to withstand earthquakes yet realistic.
Has France not taken the measure of the seismic risk on its territory?
Absolutely not. We see it well on what is happening right now. We are facing an earthquake that occurred, say, 13 kilometers from the Cruas plant, 28 km from the Tricastin plant. An earthquake that has a magnitude of 5.4 while the earthquake plus safety, is the largest earthquake taken into account to ensure the safety of facilities, is only 5.2. This means that even with safety margins, the specialists could not have predicted that we would have to deal with an earthquake so important today. For example, on the Tricastin site, there is a dike that holds the Donzere-Mondragon canal. And this dike is not seismic standards. ASN (the Nuclear Safety Authority) has authorized EDF and Orano to continue operating their facilities and to postpone until 2022 the upgrading of this dyke.
If this earthquake had not occurred at 13 km or 28 km, but had occurred much closer to the nuclear facilities, they were not necessarily sized to resist.at franceinfo
Do we have the capacity to strengthen nuclear facilities so that they can deal with a significant seismic risk?
What we see is that EDF is not able to do it. On a recurring basis, it is fortuitous to discover that facilities important for safety in our plants are not seismic standards. For example, the worker who comes to do maintenance work and who sees that there are anchors that are defective, pipes that can give up because they are rusted. It can be seen that EDF, today, is no longer able to guarantee the safety of nuclear installations in relation to a whole series of risks and in particular the seismic risk.