Despite the automatic shutdown of the reactor, EDF and the experts want to be reassuring

After 12 years of delay, a new hitch in the start-up of the EPR in Flammanville, in the Manche department. Only 24 hours after its start-up, the nuclear reactor automatically shut down on Wednesday, September 4. The divergence process has therefore been stopped. EDF has announced that its teams are carrying out technical checks. But the energy company and the experts want to be reassuring.

First of all, there is no fear of a risk of a nuclear accident. Moreover, with this emergency shutdown, it proves that the EPR safety system is working well, EDF emphasizes. The divergence process has been completely interrupted. “The automatic shutdown of a reactor is precisely to stifle the chain reaction, to prevent it from leading to an accident, explains Emmanuelle Galichet, teacher-researcher in nuclear physics at the National Conservatory of Arts and Crafts. So you just have to understand which sensor triggered an emergency stop.”

Ultra-sensitive sensors, calibrated to the nearest measurement. This hazard is therefore not surprising for Emmanuelle Galichet. “It’s been 25 years since we started up a reactor in this way. We obviously restart them at each maintenance shutdown, but starting from scratch is the first time. IThere have been many additions of sensors to the EPR compared to the existing fleet, they need to be tested and there may be failures.”

As a reminder, the EPR must reach 25% power to be connected to the national electricity grid. What must happen “by the end of fall” according to EDF, which must therefore start the whole procedure again.