EDF has brought elements tending to show "
the behavior
" of the pipes concerned by corrosion cracks on the safety systems of certain nuclear reactors, indicated Thursday the Nuclear Safety Authority (ASN), which however requests more investigations. to go around the circuits.
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"
With regard to the safety of the reactors in operation, EDF has provided justifications for the mechanical strength of the pipes concerned, and elements tending to show that the cracks only propagate over a limited thickness
", underlines the ASN in a note released Thursday.
However, the nuclear policeman is asking for additional analyses, in particular to ensure that the phenomenon does not concern other pipes linked to the main primary circuit.
In fact, the investigations carried out on the four reactors at Chooz and Civaux and at Penly 1 have revealed indications that may correspond to this phenomenon of "
stress corrosion
" also on the pipes of the cooling system of the reactor on shutdown (RRA ), according to ASN.
Until now, this problem had been spotted on the pipes of the cooling system in the event of an accident (known as “
RIS
”, for “
safety injection
”).
ASN is requesting additional analyzes to possibly confirm the problem on the RRAs, which are made of the same steel.
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"
The objective is to identify all the areas concerned and to limit the scope of the subject
", explains to AFP Julien Collet, deputy director general of the ASN.
For RRAs, the safety issue differs from RISs, as it concerns cooling during scheduled outages and not in the event of an accident.
On the other hand, there is an “
industrial issue
” if it is necessary to repair, notes Mr. Collet.
EDF had first spotted this phenomenon of corrosion on the RIS at Civaux and Penly, before having to look at other sites, forcing it to lower its forecast for nuclear production this year.
At this stage, EDF has identified six priority reactors to recheck during scheduled outages by the end of April: Bugey 3 and 4, Cattenom 3, Chinon 3 and Flamanville 1 and 2. The electrician, "
to complete his understanding of the phenomenon
“, will also control reactors representative of its various models and already stopped, underlines the ASN: Penly 1, Civaux 1, but also Fessenheim 2, for its part definitively stopped.
