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The black series continues to EDF. And each new episode reinforces concerns. The Nuclear Safety Authority (ASN) has revealed, in a note published Thursday, June 23, “some EDF reactors steam generators could have a similar anomaly to that of the tank of the Flamanville EPR “. In concrete terms, were found in large areas of concentration of carbon, “that could lead to lower mechanical properties than expected” . No less than eighteen reactors are concerned, the fifty eight of the French nuclear power plants. But unlike the EPR Norman still in the works, they are active.
In April 2015, ASN found that the steel sheets (bottom and lid) of the tank of the EPR under construction at Flamanville (Manche) was weakened by excessive carbon content in some areas. This reduces the resistance of this crucial piece, where the fission of atoms and therefore must operate to be foolproof. This anomaly had been called “very serious” with the ASN Chairman, Pierre-Franck Chevet. Tests are still ongoing and it is possible that EDF was finally forced to replace these caps
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following the discovery of these defects, the supervisor asked EDF to conduct audits on other parts may pose, too, too high in carbon concentration. It turns out that this is actually the case of “primary substance” – a steel part forged in the shape of a hemisphere. – Certain steam generators
Two reactors families are concerned
These are like the tank, “essential for security” says ASN. A steam generator is in effect a heat exchanger between the primary circuit water, brought to high temperature (320 ° C) and high pressure (155 bar) in the heart of the reactor, and the water of the secondary circuit, which is converted into steam in contact with and feeds the turbine. The lower cap itself plays an important role, since it participates in the containment of the primary circuit water. So it must be a flawless resistance
potentially defective steam generators equip says ASN, eighteen reactors at nine plants. Reactor 1 Blayais (Gironde), 4 Bugey (Ain), B1 and B2 of Chinon (Indre-et-Loire), 1 and 2 Civaux (Vienne), 2, 3 and 4 of Dampierre (Loiret), 1 Fessenheim (Haut-Rhin ), 2 and 4 of Gravelines (North), B1 and B2 of Saint-Laurent-des-Eaux (Loir-et-Cher) and four slices of Tricastin (Drôme).
two families of reactors are therefore concerned: modern units of 1,400 megawatts (MW) in the case of the central Civaux, commissioned in the late 1990s, and other, older 900 MW, on other nuclear sites. The first, more powerful, are equipped with four steam generators each, the three seconds only. The funds for these generators have been forged, for some in the Areva plant in Chalon / Saint-Marcel (Saône-et-Loire) – as the caps of the tank of the EPR – others in Japan by the company JCFC. Of the 900 MW models, these are not original equipment, which have been replaced, but more recent steam generators, and their age is not involved.
“the situation is very worrying,”
EDF ensures that “analyzes conducted since September 2015 and presented at ASN demonstrated that there are significant margins [in the steel strength], that guarantee the operation of reactors operating safely. “ she said the abnormalities do not require discontinuation of any nuclear power plant.
But the ASN considers that “the first justifications provided, on which EDF has maintained the equipment involved in service shall be comforted” . It therefore asked the company to conduct “further investigations” . These may consist of in situ measurements by ultrasound, or checks in connection with outages. The goal, said the gendarme of nuclear power, is “precisely locate the area having a high carbon concentration” and “ensure that funds do not present any defect (cracks in particular) could lead to a break in the room “.
” at this stage, there is a suspicion, that does not justify the time the reactor shutdown , says Julien Collet, Assistant Director General of the ASN . However, according to the results of future inspections, we may have to revise this position. “
Nuclear Exit Network is more radical. He claims, without waiting, “an audit of the entire nuclear fleet and the suspension of the authorization of operation of all facilities concerned” . “The situation is very worrying, judge one of its directors, William Blavette . It confirms that in terms of quality control, the French nuclear industry is not up to par and never has been. “
Whatever the outcome of further investigations, the suspicion could weigh durably on the nuclear power industry. Especially as the ASN said that “other forged components of the vessel, pressurizer and steam generator” eighteen incriminated reactors are “likely to be affected also by this anomaly “. And the same suspicion applies to other parts installed on French or foreign reactors, which came out of the factory at Le Creusot (Saône-et-Loire) Areva, whose production tracking is vitiated ” anomalies “irregularities and falsifications
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