Abstract: Apparatus for the purification of the liquid metal for cooling the core of a fast neutron reactor comprising a heat insulating envelope immersed in the reactor core and suspended from the protective slab surmounting the latter, a removable plug disposed in said slab and giving access to the upper part of the inside of the envelope and, within the latter, a cooling coil for cooling a liquid metal flow taken from the reactor core to a temperature which ensures the solidification of impurities, a filter cartridge for filtering the cooled liquid metal, a heat exchanger for the at least partial heating of the purified metal prior to its return to the reactor core and a valve for regulating the purified metal flow returned to the core, wherein it comprises a passage for returning to the upper part of the envelope purified metal from the filter cartridge, the purified metal being returned to the reactor core with the purified metal in heat exchange with the metal to be purified in a regulated flow, the regulating va

Abstract: For location of failed fuel cans in a sodium-cooled nuclear reactor, a gas flow under a pressure slightly higher than that of the sodium at the outlet of the fuel assemblies is supplied to the outlets of each of the assemblies in seriatim order. The resulting emulsion is raised by air-lift and collected in a tank located at a level higher than that of the outlet. The gas separates from the emulsion and a gas output from the tank is monitored to detect the presence of radioactive products therein.