Fixing EDF’s reactors corrosion mystery to take several years, French regulator warns

The nuclear power plant of Tricastin, France. [F. ENOT / Shutterstock]

The head of French nuclear regulator ASN said on Tuesday (17 May) that fixing corrosion problems at some of state-controlled utility EDF’s nuclear reactors would require a “large scale” plan and “several years” as he warned of a risk more reactors could be halted.

Bernard Doroszczuk told a parliamentary hearing that while EDF had checked 35 weldings for corrosion and would look at a further 105 by end-June, the cause of the problem was still unknown.

Corrosion problems have also been gaining speed, though at this stage they could not be linked to the age of the reactors, he added.

It also seemed that EDF’s 32 reactors of 900 MW, which makes up the bulk of its fleet, were not or not much affected by the corrosion problems, he said.

One possible cause for the default could be the “frenchifying of the design” of 900 MW reactors originally based on a Westinghouse design.

Separately, work to repair weldings at the Flamanville EPR plant in France will continue until August 2022, according to EDF’s timetable.

EDF faces delays and budget over-runs on new nuclear plants in France and abroad, and corrosion problems in some of its ageing reactors.

Its next-generation EPR reactors have a troubled history. EPR projects at Flamanville and Hinkley Point in Britain are running years behind schedule and billions over budget, while EPR reactors in China and Finland have been hit by technical issues.

While the safety of French nuclear plants remained at “satisfying levels” in 2021, nuclear safety must be at the heart of energy policies, ASN also said in its annual report.

France’s nuclear sector received a boost when President Emmanuel Macron in February announced plans to build at least six new nuclear reactors in the decades to come, placing nuclear power at the heart of his country’s drive for carbon neutrality by 2050.

Macron has also said at the time he wanted to extend the lifespan of older nuclear plants in the world’s most nuclear-intensive country to more than 50 years from more than 40 years currently for certain reactors, provided it was safe.

Nuclear safety still divides Europe after Japan’s Fukushima disaster in 2011.

Doroszczuk said that, as of today, the option of extending the life span of some reactors beyond 50 years was not granted.

Nuclear accounts for around 70% of France’s electricity mix.

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