The company building the Hinkley Point C nuclear plant has been accused of mismanaging faults in a similar plant under construction in France.
EDF has been rebuked by French safety regulators for failings in the construction of a prototype reactor in Normandy.
The Autorité de Surété Nucleaire (ASN) has now demanded EDF carries out a thorough analysis of welds in a critical part of the Flamanville 3 EPR reactor.
Welds in a critical part of the Hinkley Point C-style reactor in France are still showing anomalies despite two previous warnings the French nuclear safety body has said.
ASN also said it considered that the “observed discrepancies indicate a failure of the monitoring carried out by EDF” on certain activities on the site.
Weld anomalies were found in the main steam evacuation pipes of the Flamanville 3 EPR reactor – the same reactor technology being used in Hinkley Point C also being built by EDF.
The ASN said the welds were affected by deviations in design and construction.
It said that in July EDF submitted proposals for a “gap treatment approach” it intended to put in place to resolve the issue.
The proposal to upgrade part of the welds, was accepted by ASN. It involved a welding process that would meet the required rupture exclusion value for the pipes.
But the more detailed plans have now fallen short of the regulator’s requirements. The ASN said a “substantial programme of tests to analyse the mechanical properties of the welds” should now be carried out before the repairs take place.
EDF’s proposals will be examined by the ASN with technical support from the French nuclear risk body, Institut de radioprotection et de sûreté nucléaire (IRSN).
An EDF spokesperson said this was part of an ongoing communication with the regulator and that the company stood by its July estimates for the project’s completion – the loading of nuclear fuel is now scheduled for the end of next year with commercial activity starting in 2020 and costs revised up again from €10.5bn (£9.23bn) to £9.6bn.
“Our position is we will carry on with the safety demonstration and of course we will take into account the recommendations and the requirements of the ASN,” the spokesperson said.
Like what you’ve read? To receive New Civil Engineer’s daily and weekly newsletters click here.