French utility EDF said on 18 September that the discovery of problems with weldings at some of its nuclear reactors would not lead to any closures.
“At this stage of the technical investigations being carried out on these components, EDF believes that the observed deviations do not adversely affect the components’ fitness for service and do not require immediate action,” EDF said in a statement.
Problems had been identified with 16 steam generators installed on six operating reactor units: Blayais 3&4, Bugey 3, Fessenheim 3, Dampierre-en-Burly 4 at Dampierre-en-Burly and Paluel 2. The generators were affected by non-compliance in a stress-relieving heat-treatment process but are deemed safe to continue in operation, EDF said. Earlier in September, EDF had informed the French Nuclear Safety (ASN), of its initial investigations concerning deviations in certain nuclear-related components produced at Framatome's Saint-Marcel site. Investigations at Saint-Marcel are ongoing.
EDF confirmed the non-compliance concerned an excursion from temperature ranges in certain areas during manufacturing operations, specifically involving detensioning heat treatment on some steam generator welds and pressuriser seals.
In a separate statement, Framatome said the investigations "confirm at this stage that the mechanical integrity of the components is not called into question”. The stress-relieving heat treatment process is not being used while the investigations are being completed, but other activities at Saint-Marcel are continuing, Framatome has said. Framatome is owned by EDF (75.5%), Mitsubishi Heavy Industries (19.5%) and Assystem (5%).
Affected components not yet in service include four steam generators and the pressuriser that have been installed at the EPR under construction at Flamanville 3. Three replacement steam generators have been delivered to Gravelines NPP units 5 and 6, but are not yet installed. EDF and Framatome said they are continuing their technical investigations "with extreme diligence" and will keep ASN informed.
The Saint-Marcel site, in Saône-et-Loire, assembles the heavy equipment for nuclear reactors, including vessels, steam generators and pressurisers. Since it was established in 1975, the plant has supplied components for 106 nuclear reactors worldwide, according to Framatome. Following its statement, EDF’s shares rose more than 3%, recovering to some extent from the 7.1% fall, which followed discovery of the component faults.
Meanwhile, France announced on 17 September that it would give out free iodine tablets to 2.2 million people living near to nuclear power plants to help protect them from radiation in case of an accident. ASN said people living within 10-20km of a nuclear power plant, as well as some 200,000 institutions, would receive a letter informing them they can pick up the tablets from the nearest pharmacy. Previously, iodine tablets were distributed to those living within a 10km radius of a plant.