how the “large fairing” of nuclear power plants tries to extend their operating life

Securely attached helmet, full suit and dosimeter for radioactivity in position: everything is ready to enter the reactor core of the Saint-Laurent-des-Eaux nuclear power plant. In front of the entrance hall, Magali Lefèvre, technical director of the plant: “At the exit of this airlock, a double door, we will really find ourselves in the reactor building.” We enter one of two 900 megawatt reactors. It is shut down for its fourth ten-year inspection. This in-depth examination should make it possible to obtain the authorization to operate for another ten years. “It’s a huge check-up of the installation, where we will check a lot of equipment, explains Magali Lefèvre. These are visual checks, but also by ultrasound, such as ultrasounds, to ensure that our equipment has the expected performance.”

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This time, for this reactor commissioned in August 1983, it is more than a ten-year inspection. Forty years is a milestone for the reactors in the fleet: it is the minimum lifespan given to them by their designers. EDF has therefore planned a reinforced program, called “grand fairing”. Launched in 2015, it aims to upgrade reactor safety standards, for example by adding heavy equipment. “We have an emblematic modification, explains Arnaud Bénard, head of activities in reactor number 2 at Saint-Laurent-des-Eaux, this is the corium modification: a device for recovering molten fuel is installed in the event of a serious accident. It’s very hypothetical, but we’re preparing for the worst to reach EPR standards.”.

Towards a lifespan “beyond 60 years”

With feedback from Fukushima and adaptation to climate change, EDF hopes to make its plants part of the long-term future. Sylvie Richard is director of the “grand carénage” program from EDF. “We have created a new project for the fifth ten-year inspections of the 900 megawatt series, which will allow these units to obtain authorization for continued operation between 50 and 60 years. It also projects us onto all the components of a nuclear power plant, to reflect on their renovation and replacement, with a view to lifespan, including beyond 60 years”.

Last year in Belfort, the President of the Republic reconsidered the objective of closing 12 reactors, enshrined in law. The “large fairing” therefore now applies to all 56 units. When it is finished, this second youth of the historic fleet will have cost 66 billion euros, more than the estimated cost of the new EPR 2 reactors.