Finally ! A quick word to sum up such a long wait. Due to slips in the schedule, this sixteen year and five month project (including eleven years and eleven months late, since it was initially supposed to be completed in June 2012) seemed endless. But, obviously, everything ends up happening: with the imminent announcement of the first fuel load, the public group EDF is preparing to formalize, in the days to come, the commissioning of its third generation nuclear reactor, the now famous EPR (European Pressurized Reactor) at the Normandy Flamanville power station (Manche). The Nuclear Safety Authority (ASN) gave it authorization on May 7, or exactly six thousand days after the laying of the first concrete in the nuclear building, on December 3, 2007.
The first loading, the real start of the EPR, requires several days of work – without further details, at this stage, from EDF. A meticulous task awaits the teams: from a storage pool, they have to lower 241 fuel assemblies to the bottom of the reactor vessel, 10.6 meters high.
Already received between October 2020 and June 2021, all these “fagots” include “pencils”, that is to say sheaths stacking uranium pellets. The exercise is similar to another, more usual one: every year or every year and a half, depending on the model, the operator carries out the partial reloading of its fifty-six reactors already operating in the country.
Full power
Several stages, after that of the first loading, will still be on the schedule for the fifty-seventh reactor. First, in the coming weeks, tests to allow divergence, that is to say the start of nuclear fission. Then, in principle from summer, it will be time for connection to the electricity network. It is only from this coupling, when the reactor has reached 25% of its power, that its 70 meter long turbine will be able to start supplying French homes with electricity.
“Fission, in other words the chain reaction of neutrons, can only take place very graduallyrecalls Emmanuelle Galichet, teacher-researcher in nuclear sciences and technologies at the National Conservatory of Arts and Crafts. You can’t be 100% right away. » Full power is instead announced for the end of the current year.
“Certain tests can only be carried out once the reactor is loaded, to verify the hypotheses of the safety demonstration”, adds Karine Herviou, deputy director general of the Institute of Radiation Protection and Nuclear Safety. For example, EDF must test the behavior of the reactor and its ability to stop the chain reaction within the planned time frame, in the event of an incident or accident. “This parameter requires checking the fall time of the control clusters [matériaux chutant automatiquement pour absorber les neutrons et stopper le réacteur en cas de problème] »specifies Mme Herviou.
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