London — French nuclear operator EDF has identified 16 steam generators with "discrepancies" installed at six nuclear reactors, but they remain fully operational with "no immediate need for repairs," it said Wednesday.
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The reactors hosting the faulty generators, manufactured by Framatome, are Blayais 3 and 4, Bugey 3, Fessenheim 2 and Dampierre 4 (all 900 MW units) and Paluel 2 (a 1,300 MW reactor), EDF said in a brief note.
"At this stage considering the technical instructions relating to these components, EDF considers that the observed discrepancies do not call into question the serviceability of equipment and do not require immediate treatment," it said.
EDF and Framatome were continuing technical analysis "with extreme diligence" and will keep the nuclear safety regulator ASN informed, EDF said.
Last week, ASN chairman Bernard Doroszczuk said the regulator would decide within a month what action needed to be taken by EDF following detection of steam generator weld deviations.
EDF first informed ASN on September 9, causing French winter power prices to spike by around 20%.
French Q4 base power fell back 8% in Wednesday trading at Eur55.90/MWh by 1 pm London time after closing Tuesday at Eur60.94/MWh, EEX exchange data show.ed
Concerning components not yet in service, EDF and Framatome identified four steam generators and the pressurizer for the new Flamanville 3 EPR reactor as well as three new replacement steam generators not yet installed at the 900 MW Gravelines 5 and 6 reactors, it said.
'No structural flaw'
During a conference call Wednesday, EDF's deputy head of its French nuclear fleet, Regis Clement, said the first results of its investigation showed "it was not a structural flaw" and there was "no necessity at present to stop any reactors."
ASN gave EDF a "no objection" to proceed with the replacement works, Clement added.
He also said that EDF was not "prejudging the outcome" of ASN's investigations and potential requests, but that he was confidant on a positive outcome for ASN's investigation.
The actual physical replacement of the steam generators at Gravelines 5 was not due to be completed before October, which allowed time for ASN to "give its verdict" on the seriousness of the deviations, Clement also said.
Steam generators are a very large component (weighing up to 500 mt) in the primary system of a nuclear plant with three of the units in each 900 MW reactor to be replaced after approximately 20 years of operation.
While steam generator replacements were not expensive -- at around Eur30 million each ($33 million) -- any outages would be time extensive, according to analysts at SocGen.
Replacing them was "a major operation, involving an extended maintenance outage. The generator also needs to be manufactured on purpose, with a long industrial lead time," the bank said.
Of the 16 generators, three are at Fessenheim 2, which is set to close in June 2020, although its license does not expire until summer 2022.
At Paluel 2, meanwhile, inspection of a steam generator in 2015 led to a three-year outage after the steam generator was dropped and had to be replaced.
EDF operates 58 reactors with 63 GW capacity across 19 sites in France.
It has one new plant in construction at Flamanville 3 EPR. Operation has been delayed by sub-standard weldings in the containment area, with EDF yet to announce a new start-up timetable after ASN rejected its initial solution.
--Andreas Franke, firstname.lastname@example.org
--Edited by Jonathan Loades-Carter, email@example.com