Abstract: A heat exchanger comprising an outer casing closed at its hot and cool ends by two tube plates, a cluster of tubes which is connected to the tube plates to discharge into inlet and outlet collectors of a fluid flowing inside the tubes, and inlet and outlet tubings of a liquid flowing in the casing and around the tubes, wherein the exchanger comprises at its hot end a device for protecting the tube plate, such device comprising two plates united by a casing to define a first zone filled with such liquid in the static state forming a thermal screen, such plates being substantially parallel with the tube plate and a first one of such plates being disposed adjacent the tube plate, the protective device also comprising passages extending through such zone from one plate to another, and means for setting up a negative pressure between such first plate and the tube plates, to ensure that such liquid flows towards the tube plate inside such passages.

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