French nuclear reactor on English Channel has a 'deep' crack in cooling system

France is heavily dependent on its nuclear power sector for its energy needs, so the latest news that a coolant pipe in one of its nuclear reactors along the Channel coast is seriously corroded is a major cause for concern.

The French energy group EDF discovered the 2.3cm deep crack in a 2.7cm-thick cooling pipe for the Penly power plant on March 6, the French nuclear power regulator Autorité de Sûreté Nucléaire (Nuclear Safety Authority, or ASN) said in a statement. The Penly plant is located near Dieppe along the English Channel, across from Brighton in the UK.

The crack in the safety injection circuit of the Penly plant's Reactor 1 is the result of stress corrosion and was submitted to the regulator as an update to another report of stress corrosion in Reactor 3 of the Cattenom nuclear power plant, as well as corrosion reports in three other reactors at different plants, including Penly. The notice does not mention the depth of the corrosion at the plants other than Penly, so it's not clear whether the crack in Reactor 1 is the deepest one found.

The 15.5cm long crack runs about a quarter of the circumference of the damaged pipe and is located near a weld point in the pipe.

"This line was considered by EDF as not susceptible to stress corrosion cracking due in particular to its geometry," the ASN statement reads. "However, this weld underwent a double repair during the construction of the reactor, which is likely to modify its mechanical properties and the internal stresses of the metal in this zone."

ASN goes on to state that while this crack is concerning, the safety system for the nuclear reactor is designed so that it could tolerate a rupture of one of these coolant pipes. The ASN statement goes on to note that some of the corroded pipes at the Penly and Cattenom nuclear power plants have already been replaced as part of the ongoing safety inspection process, but it does not say if the severely cracked pipe has been replaced as well.

"This [stress corrosion] event had no consequences on the personnel or on the environment," ASN said. "Nevertheless, it affects the safety function related to reactor cooling. Due to its potential consequences and the increased probability of a rupture, ASN classifies it at level 2 on the INES scale with regard to reactor 1 of the Penly nuclear power plant and at level 1 for other reactors concerned."

Maintenance of power plants in France comes at a critical time

This latest problem with a nuclear reactor comes at a tough time for France, which has been struggling to meet its energy needs due to the war in Ukraine affecting the supply of natural gas from Russia.

Normally, France receives about 70% of its energy from nuclear power, with other sources making up the remainder, but with Russian gas cut off from Europe, France was recently forced to turn to Germany and other European nations for energy to make up for the shortfall.

What's more, France's nuclear power infrastructure has encountered a number of maintenance issues in recent years, according to French news outlet RFI, leading to a deepening of concerns over France's energy security.

To layer yet another problem on top of everything else, EDF, which is a state-owned utility, is heavily in debt to the tune of €64.5 billion as of 2022, with losses hitting €17.9 billion last year, only compounding the crisis.

With these new maintenance costs and the prospect of many more to come as France's nuclear infrastructure continues to age, those losses could very well grow even further.