French nuclear regulator Autorité de Sûreté Nucléaire (ASN) has advised the UK Office for Nuclear Regulation (ONR) that paperwork related to the manufacture of components for use in UK NPPs by Areva's Le Creusot forge may contain "inconsistencies, modifications or omissions". The Sizewell B reactor is the only UK reactor which has these components. ONR announced on 13 May that it is "engaged" with and EDF "concerning the reports of anomalies and inconsistencies in quality documentation".
Earlier this month, the ASN said an ongoing quality audit at the 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". Areva said some 50 of these parts are thought to be in service at French NPPs.
Areva said in early May, "At this preliminary stage, no information has come to light that would jeopardize the mechanical integrity of the parts." However, ASN has asked Areva to provide a list of the parts concerned as soon as possible, "along with its assessment of the consequences for the safety of the facilities, jointly with the licensees concerned".
ONR said, "Areva is in the process of completing the characterization of these historical irregularities and their consequences, and has committed to contact affected foreign customers by 31 May". It added: "We will await the conclusion of the Areva review before deciding whether there is a need for any specific intervention in the UK." ONR believes the irregularities in paperwork occurred before any procurement of forged parts for the two EPR reactors planned for Hinkley Point C. Sizewell B is the only reactor in the UK that has a small number of reactor components supplied by the Areva facility, ONR said. The 1,198MWe pressurised water reactor, which started up in 1995, is currently shut down for its scheduled outage. "We will be seeking the necessary assurances for the reactor components before we permission the restart of the Sizewell B reactor," ONR noted.
The upper and bottom heads of the reactor pressure vessel for the EPR under construction as Flamanville 3 EPR were manufactured at the Le Creusot facility in September 2006 and January 2007, respectively. A high carbon content in those parts prompted Areva to review the company's quality process in 2015.
Areva's Creusot Forge and Creusot Mécanique subsidiaries supply big forgings and castings mainly for the nuclear industry. Creusot Forge is one of a few facilities that can produce the heavy nuclear-grade forgings required for large components such as steam generators, reactor pressure vessels and primary pumps. Creusot Mécanique carries out precision finish machining on large components.