24 Oct (NucNet): France’s nuclear operator EDF has confirmed the shutdown dates of five nuclear reactor units that have been ordered to undergo checks for high carbon concentrations on the primary bottom heads of steam generators. Last week the nuclear regulator, the Autorité de Sûreté Nucléaire (ASN), said it had asked EDF to carry out the checks within three months and that the reactors should be shut down without waiting for planned refuelling outages. ASN said the steel in the heads might be affected by high carbon concentrations similar to those found at the company’s Flamanville-3 EPR under construction in northern France. The reactors and shutdown dates are: Tricastin-4 (22 October 2016 to 19 December 2016); Fessenheim-1 (10 December 2016 to 3 January 2017); Gravelines-4 (17 December 2016 to 10 January 2017); Civaux-1 (23 December 2016 to 15 January 2017); Tricastin-2 (23 December 2016 to 15 January 2017). Earlier analysis had shown that steel from Areva’s Le Creusot forge facility and Japan Casting and Forging Corporation in Japan might have significant carbon concentrations. This steel was used in the primary bottom heads for 18 reactors, six of which have already been cleared for restart and normal commercial operation. The six are: Blayais-1, Chinon-1, Chinon-2, Dampierre-2, Dampierre-4 and St. Laurent B1. EDF was then asked to carry out the additional checks on the remaining 12 reactors. The checks have either been completed or are under way on seven of the reactors (Civaux-2, Dampierre-3, Gravelines-2 Tricastin-1, Tricastin-3, Saint-Laurent B2 and Bugey-4. Problems with manufacturing records were first discovered at Le Creusot in April 2016. Areva told ASN at the time that an internal audit had found irregularities in manufacturing checks on about 400 parts produced since 1965, about 50 of which were still in use at French nuclear power stations. The irregularities consisted of “inconsistencies, omissions or changes in manufacturing files”.
