[en] In the technology of liquid sodium cooled fast reactors, the necessary processes for washing and decontamination have been demonstrated. For sodium removal, different solutions have been considered and tested in France. The studies have been progressively oriented toward defining a process using a fine dispersion of water in a gas (atomization). The results obtained by that method on non-radioactive components were satisfactory insofar as the efficiency and safety of the operation was concerned. The purpose of decontaminating components from the reactor primary circuits is to reduce the level of surface activity to a level compatible with personnel access without biological shielding. The treatment Is comprised of two stages: (i) washing, to remove any residual sodium, and (ii) decontamination which alternately applies alkaline and acid solutions, to dissolve the deposited radionuclides without significant attack on the surface. The treatment, recently applied to components from in-service reactors, generally met the design objective. (author)