Device for removing cooling fluid, making it possible to locate defective arrays in a nuclear reactor in operation

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.