Patent Number: 045171530
Section: claims

1. In a fast neutron nuclear reactor comprising a core consisting of fuel assemblies arranged side by side with their lateral faces in contact in va vessel containing a reactor cooling fluid circulated by means of pumping, so as to traverse the core in the longitudinal direction of said assemblies, and a device incorporating means for detecting and localizing defective assemblies by detecting fission products in the cooling fluid, consisting of at least one localizing module and sampling conduits for abstracting the cooling fluid, each being associated with a fuel assembly, independently joining each of the zones situated at the exit of each of said assemblies to the localizing module and assuring the transport of said cooling fluid from the core exit as far as said modules, the improvement consisting of at least two completely independent localizing modules and an arrangement of the sampling conduits joining the exit of said assemblies to said modules such that, for each assembly of said core, there is at least one adjacent assembly in contact through the intermediary of one of its lateral faces, which is connected by its sampling conduit to a localizing module different from the module to which the first assembly is connected by its sampling conduit. 2. The improvement according to claim 1, wherein said core is divided into at least two parts, each comprising a set of assemblies, sampling conduits being associated with the assemblies of a set connected to one or the other of two localizing modules which are independent of the localizing modules to which the sampling conduit associated with the assemblies of the other sets are connected. 3. The improvement according to claim 2, wherein said core is divided into three parts, comprising three pairs of totally independent localizing modules, each associated to the set of assemblies in a part of said core, the sampling conduits of which are connected to either of the two localizing modules of the corresponding part of said core. 4. The improvement according to any one of claims 1 to 3, the sampling conduits of said assemblies being connected to one or the other of two independent localizing modules, respectively, arranged over rings coaxial with the axis of said core.