EDF was summoned this Tuesday by the nuclear police to “review its strategy” to solve the problems that have seriously afflicted its plants since the end of 2021, after the discovery of a new fissure in an emergency circuit of a stopped reactor, Penly. 1, in Seine-Maritime.
Unnoticed until its media coverage on Tuesday by the Context site, an EDF note published on February 24 indicates that it detected at Penly 1 a “significant stress corrosion defect” in an emergency piping used to cool the reactor in the event of a “emergency”. . In the process, the Nuclear Safety Authority (ASN), nuclear police in France, asked EDF to “review its strategy” on dealing with stress corrosion cracking in some of these reactors.
A “dark” year 2022 for EDF
Although EDF believed that it would emerge from the crisis in dealing with this phenomenon, this announcement casts new uncertainties on the electrician’s prospects for 2023, after a dark year weighed down by the setbacks at its nuclear park, which contributed to deepening its losses. and debt
In fact, the EDF nuclear fleet (56 reactors) has suffered an unprecedented crisis since the discovery in October 2021 of a stress corrosion phenomenon in the most recent reactors. This problem had forced EDF to shut down many reactors for large-scale inspection and repair operations, contributing to the colossal losses recorded by the electrician in 2022. France thus experienced its lowest level of electricity production in 2022 since 1992. and had to import electricity from its European neighbors.
A crack in a strategic place
At the Seine-Maritime reactor, the new defect was detected during a “metallurgical survey” on “a weld deposited in January,” according to the note published on the group’s website. Until now, it was only about microcracks, on the order of a few millimeters. But the new crack is near a weld in an emergency pipe used to cool the reactor in an emergency. It “extends over 155mm, or about a quarter of the circumference of the pipe, and its maximum depth is 23mm, for a pipe thickness of 27mm,” according to the ASN.
The pipe may have been weakened by a repair operation aimed at “realigning” the circuits, at the same time as the reactor was built. “This line was considered by EDF as not susceptible to stress corrosion cracking due in particular to its geometry. However, this weld was subjected to a double repair during the construction of the reactor, which probably modifies its mechanical properties and internal stresses of the metal at the level of this zone”, explains the ASN.
Question about keeping the 6 reactors of the same type P’4 in operation
“The novelty is the depth of the crack, that is to say 85% of the thickness of the pipe, and the explanatory factor linked to this notion of double repair during a circuit realignment operation,” says Yves Marignac, an expert in energy and member of ASN advisory groups. For the expert, “the fact that larger cracks are possible raises the question of keeping the 6 reactors of the same P’4 type in operation pending their preventive repair, announced in December by EDF for the current 2023.
The Penly plant, made up of two reactors, was put into operation between 1990 and 1992. It is part of the series of the most powerful reactors, known as “P’4”, with a power of 1,300 MW.
Source: BFM TV
