Inquiry into French nuclear plant pressure vessel problems reveals series of "irregularities"
18 May 2016
The upper and bottom head of the reactor pressure vessel for the EPR reactor installed at the Flamanville nuclear power plant, currently under construction, were manufactured at Areva’s Le Creusot Forge facility in central France in 2006 and 2007. In 2014, tests on a vessel head similar to that of the Flamanville EPR revealed the steel had "lower than expected mechanical toughness values".
Flamanville - Image: EDF
Following this discovery, ASN (Autorité de Sûreté Nucléaire) asked Areva to conduct a review of the quality of production at the Le Creusot plant. The review covered parts quality, the organisation and practices at the plant, and its safety culture.
At the end of April, AREVA informed ASN of the first results of this review, highlighting irregularities in the production of about 400 parts produced since 1965, of which 50 are in service within French nuclear power plants.
The ASN said, "These irregularities consist of inconsistencies, modifications or omissions in the production files, concerning manufacturing parameters and test results." It 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.
"The review process will need to be seen through to completion in order to assess all the anomalies which may have affected past manufacturing operations and draw any relevant conclusions regarding the safety of the facilities," ASN said.
Areva has set up a technical committee with EDF, which operates French nuclear plants, and it will pass on its findings to ASN. It said: "At this preliminary stage, no information has come to light that would jeopardise the mechanical integrity of the parts."
Le Creusot Forge specialises in the supply of big forgings and castings destined mainly for the nuclear industry. It is one of a few facilities worldwide that can produce the heavy nuclear-grade forgings required for large components such as steam generators, reactor pressure vessels and primary pumps.
A Le Creusot Forge-built reactor pressure vessel destined for the Hinkley Point C nuclear power plant in the UK is now being used in tests to assess the safety of the Flamanville component. A replacement vessel for the proposed Hinkley plant is to be made in Japan.
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