Patent Number: 046559965
Section: claims

1. A fast neutron nuclear reactor, which comprises a vessel containing a liquid cooling metal, a core immersed in this metal, the vessel having a flooring on which rests a structure for the core, said core being constituted by a juxtapositioning of assemblies fixed into the structure, the liquid cooling metal circulating in an upwards manner in the core, the liquid metal being called "cold liquid metal" before its circulation in the core and "hot liquid metal" after it has passed into the latter, wherein it comprises a fuel element storage structure, which is independent of the core structure and is arranged concentrically with respect to the latter and rests on the flooring, the core structure and the independent storage structure each comprising upper and lower perforated plates and stays, each stay having an inner cylindrical through housing for receiving a foot of a fuel assembly, said stays being fitted in the plates, relative labyrinth upper and lower sealing means provided between the foot of said assembly and said stay, said relative sealing means letting leaks go through them, the plates of said core structure determining a volume which is communicated with a volume underneath said lower plate, so that the leaks which take place through said lower labyrinth sealing means feed the volume underneath the lower plate with cold liquid metal and, then, the fuel assemblies of the independent core structure. 2. A reactor according to claim 1, wherein the storage structure hydraulically connected to the flooring is constituted by several modules. 3. A reactor according to claim 1, wherein the storage structure connected hydraulically to the flooring is constituted by a complete one-piece ring. 4. A reactor according to claims 2 or 3, wherein the transfer of the assemblies out of the reactor vessel is effected by means of a loading and unloading container, the storage structure having a free space in which is located the reactor assembly loading and unloading station. 5. A reactor according to claim 3, wherein the storage structure is formed in one piece with the flooring. 6. A reactor according to claim 2, wherein the modules constituting the storage structure are placed and fixed on the flooring. 7. A reactor according to claim 1, wherein the storage structure hydraulically connected to the flooring is constituted by two half-rings.