“There is no risk for the environment or for public health”, assures on franceinfo Karine Herviou, deputy director general of the Institute for radiation protection and nuclear safety (IRSN). A leak that occurred on Wednesday November 2 within the primary circuit of reactor No. 1 of the Civaux nuclear power plant (Vienne) risks delaying its restart scheduled for January 8, 2023.
franceinfo: Is this leak worrying?
Karine Herviou: There is no risk to the environment or to public health. This is an event that took place during what is called a hydraulic test of the primary circuit. This is the circuit that cools the nuclear fuel and transports this heat to heat exchangers that will vaporize water and turn the turbines. This is the second radioactivity containment barrier.
In normal operation, a reactor runs at 155 bars. Every ten years, there is a hydraulic test of this circuit. This means that EDF increases the pressure to more than 200 bars and will inspect this circuit to check that there is no leak. This is an operation that is done without fuel inside the tank.
What caused the leak?
It’s a kind of plug that was put there to prevent water from leaking. It was this plug that broke and caused the leak. It is not a serious or heavy event in terms of repair.
“It’s relatively simple to repair and the repair times are not very long. EDF will bring in a robot to recover the contaminated elements at the level of the leak and isolate the leak. It will take a few days.”
Karine Herviou, Deputy Director General of IRSNat franceinfo
Are these frequent incidents?
No, this is the first time this has happened in France. The event on Civaux is a problem of assembly of this famous stopper. This is not a maintenance defect but a problem when fitting this plug or a failure of the plug itself. This is not related to the maintenance of the reactors in particular.
Should we worry about the state of the French nuclear fleet?
There is an accumulation of delays on reactor outages for stress corrosion problems which require inspections and sometimes repairs. There are also reactors that have been shut down for safety improvements, since as part of the 40-year upgrade to 900 megawatt reactors, EDF has undertaken to carry out a large number of works, in particular to add safety circuits . So this also generates significant unavailability. The two are cumulative, hence a large number of reactor shutdowns.