French safety authority IPSN has said that it needs more information before it can rule on a requiest from EdF to reload fuel into Cattenom 3 in spite of a number of fuel failures in the 1300MWe reactor’s last operating cycle. The cause of these fuel failures has still not yet been determined.

The unit was shut down on 27 January for a 10-year outage. Operators had noted a rise in primary circuit activity during the last cycle, but this had remained within specification. However, when the core was examined, it was found to have a total of 92 leaking fuel rods in 28 assemblies.

Fretting has been postulated as the probable cause of the failures, but it is not yet known what has caused the fretting.