France's nuclear safety authority, Autorité de Sûreté Nucléaire (ASN), has detailed the conditions to be satisfied, before Areva can resume operations at its Le Creusot forge, which was closed in December 2015 following the discovery of quality assurance issues.
In April 2015 ASN discovered an anomaly in the composition of the steel in certain zones of the vessel closure head and the vessel bottom head of the EPR reactor under construction at the Flamanville NPP. ASN asked Areva NP and EDF to "learn all possible lessons from this event".
Then in May 2016, ASN said an ongoing quality audit at the forge - had identified "irregularities" in paperwork on some 400 plant components produced there since 1965. Areva bought the facility in 2006. The issues "comprise inconsistencies, modifications or omissions in the production files, concerning manufacturing parameters and test results", ASN said.
Areva submitted an action plan to ASN in August 2016 intended to guarantee the quality of future production at Le Creusot and ASN carried out a number of inspections. These included a multinational inspection in line with the inspection protocol of the Multinational Design Evaluation Programme (MDEP) in late 2016. This examined the review method for the component files already assessed and those undergoing assessment. It also examined organisational and technical changes, as well as changes in quality and nuclear safety culture at the plant.
ASN told Areva the inspectors had noted that the action plan was "in the process of being implemented” but considered a certain number of subjects needed to be adapted and supplemented, such as management of change, human resources, exhaustiveness of root cause analyses, detection of irregular practices, reviews of manufactured component files, management of current manufacturing processes, internal monitoring, and the quality and nuclear safety culture.
Areva recently informed ASN that it intended to resume forging operations.
Three processes are still under way, according to ASN:
- The search for technical anomalies on other EDF reactor components similar to those detected at Flamanville, which has enabled EDF to identify similar anomalies on the channel heads of certain steam generators;
- Manufacturing quality reviews on parts at Areva NP manufacturing plants, which enabled Areva NP to detect irregularities in the manufacturing files from Creusot Forge; and
- Initiation of a review of basic nuclear installation licensee monitoring of their contractors and subcontractors, of ASN oversight and of alert mechanisms.
ASN has now written to both Areva and EDF informing them of the preconditions required for resumption of forging. "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."