Framatome is carrying out further studies at its Saint-Marcel site in France after discovering temperature ranges in some stress-relieving heat treatments carried out on steam generator welds and pressuriser seals had deviated from technical standards, the company said today.The Saint-Marcel site (Image: Framatome)
According to Framatome's majority owner EDF, the deviation concerned an excursion from temperature ranges in certain areas during manufacturing operations, specifically involving detensioning heat treatment on some steam generator welds. In-service components, as well as new components which have not yet been installed, are concerned, it said.
"Work conducted by a team of experts has made it possible to characterise the causes more precisely whilst gathering the data to establish that the integrity of the components is not questioned. Studies are continuing to finalise the analysis," Framatome said today.
EDF said today the deviation concerned in-service components as well as new components which have not yet been installed on any sites.
"From the time it was informed of the deviation, EDF - along with Framatome - has been conducting in-depth investigations to identify all affected components and reactors, as well as to ascertain their fitness for service," EDF said. The company on 9 September informed the French nuclear regulatory authority of its initial investigations and will provide provide additional information as characterisation work progresses, it said.
The specific stress-relieving heat treatment process is not being used while the investigations are being completed, but other production activities at the Saint-Marcel site are not affected, Framatome said.
The Saint-Marcel site, in Saône-et-Loire, assembles the heavy equipment for the primary loop of nuclear reactors, including vessels, steam generators and pressurisers. Since its establishment in 1975, the plant has supplied components for 106 nuclear reactors worldwide, according to company information.
Framatome is owned by EDF (75.5%), Mitsubishi Heavy Industries (19.5%) and Assystem (5%).