[en] The spring is made by a strip folded into two arms gripping a plate of the grid, welds joining the arms through windows of the plate and a U-shaped section to one of the arms bearing against the other arm and of the same width as it

[en] One of the criteria for rejecting COntrol Rod Assemblies is the clad cracking linked to the diameter increase at the bottom of the rods. Examinations in Hot Cells have been performed to understand the rod behaviour under operating conditions. Swelling of absorber rod is due to transmutations which lead to modification in the chemical composition of the alloy and, further, to a new phase formation. The cold worked structure of the clad is replaced by many small dislocation loops which lead to grain hardening and low ductility. Under the combined effects of swelling under irradiation and absorber slumping because of creep and repeated shocks, the absorber comes into contact with the cladding. When the gap is closed, the absorber applies a strain to the cladding which cracks. However, the intergranular cracking cannot be only explained by the drastic decrease of cladding ductility under irradiation. As a short-term remedial action, FRAMATOME combines a reduction of diameter in the lower part of the rod with helium rod filling and, in some cases, a decrease of the spring hold down force. (authors). 6 figs., 6 tabs., 11 refs