Nuclear Monitor #926

Jan van Evert

The French electricity company EDF has decided to completely recompose the core of the new EPR reactor in Flamanville. There are problems with the water tightness of the nuclear fuel rods. This decision is based on feedback from the Taishan reactor in China, which experienced the same type of problem during the second cycle of the EPR production cycle.

After more than two months of shutdown, the Flamanville 3 reactor prepares to be reconnected to the electricity grid on Monday 21st April. EDF has also announced the future replacement of part of the fuel.

The energy company has to deal with neutron flux disturbances at the bottom of the reactor vessel. This problem could lead to the fuel rods losing their seals. These problems have already been observed at the Taishan EPR in China, during its second production cycle.

As a preventive measure, the core of the Flamanville EPR reactor will therefore be rebuilt with reinforced fuel rods after its first unit outage, at the end of 2026 or early 2027. “This is a precautionary measure”, stresses EDF, “To date, there have been no leakage problems. We are simply taking into account international experience feedback”.

This is not the first incident with this reactor: it has already been shut down three times since it was connected to the grid on December 21st last year. The problems are piling up: faulty temperature sensors, alternator problems and so on (see Nuclear monitor 925).