Method of handling fuel assemblies and rods when reloading a nuclear reactor

Method of handling fuel assemblies and rods in the reloading with fuel of a nuclear reactor containing assemblies closed by two caps and having a framework inside which fuel rods are disposed vertically, the reloading being effected with the vessel of said reactor in open position and the swimming pool surrounding said vessel filled with water, and comprising transfers of fuel assemblies from one position to another inside the core of said reactor, replacement of unsuitable assemblies by suitable assemblies, and various tests, each replaced assembly being taken from the vessel of said reactor, placed in a transfer container and conveyed, in horizontal position, into the swimming pool for the fuel adjoining the reactor, said method comprising the steps of

• (a) placing said assembly in a vertical position inverted relative its operative position in the core of the reactor, i.e., with its lower cap uppermost;
• (b) de-mounting said lower cap so that access can be had to the ends of said fuel rods;
• (c) identifying fuel rods requiring replacement in said assembly if such identification has not been carried out previously;
• (d) simultaneously taking up a set of rods to be replaced;
• (e) continuing the taking up of rods in sets until all the rods to be replaced have been taken up;
• (f) depositing said sets of rods in a storage area;
• (g) taking up replacement rods corresponding precisely to the sets of rods to be replaced;
• (h) depositing said replacement rods in sets in the framework of said fuel assembly;
• (i) replacing the lower cap of said assembly;
• and
• (j) conveying said assembly into said reactor vessel at its new location.