ASN announced in April 2015 the discovery of an anomaly in the composition of the steel in certain zones of the vessel closure head and the vessel bottom head of the Flamanville EPR reactor. The detection of this anomaly led ASN to ask Areva NP and EDF to "learn all possible lessons from this event". The forge has been out of operation since December 2015. However, in June this year, ASN provisionally ruled that Flamanville 3 can start up safely, but that the head of its reactor pressure vessel will need to be replaced by the end of 2024.
In May 2016, the regulator said an ongoing quality audit at Areva's Le Creusot forge - which Areva bought in 2006 - had identified "irregularities" in paperwork on some 400 plant components produced there since 1965. The issues "comprise inconsistencies, modifications or omissions in the production files, concerning manufacturing parameters and test results", it said.
In June last year, ASN said it had identified 18 French nuclear power reactors operated by EDF - of both 900 MWe and 1450 MWe capacity - whose steam generators could contain high carbon concentrations. The regulator ordered EDF in October to carry out additional inspections on the steam generator channel heads of certain reactors, within three months.
Areva submitted an action plan to ASN on 1 August 2016 aimed at guaranteeing the quality of future production at the Le Creusot facility. The company has informed ASN of its intention to resume forging operations there.
ASN has conducted several inspections of the forging facility, including a multinational inspection carried out in accordance with the inspection protocol of the Multinational Design Evaluation Program (MDEP). The aim of this inspection - carried out from 28 November to 2 December 2016 - was to examine the review method for the component files already assessed and those currently undergoing assessment. It examined the organisational and technical changes, as well as the changes in terms of quality and nuclear safety culture implemented within the Creusot Forge plant.
In April, ASN wrote to both Areva and EDF informing them of the preconditions required for resumption of forging of components for use in French nuclear power plants.
"Prior to the restart of manufacturing, ASN will check that the action plan is complete and that the actions already taken have proved to be effective," ASN said. "Subsequently, ASN will maintain increased oversight and monitoring of Areva's Creusot Forge plant."
Researched and written
by World Nuclear News