[en] New ultrafiltration processes developed for the treatment of low and medium active radioactive wastes, were applied successfully to a variety of simulated and real wastes, including magnesium alloy clad spent storage fuel pond waters, reprocessing plant solvent wash liquors, plutonium production effluents and mixed site effluents. After initial laboratory scale feasibility experiments the process was scaled up successfully, using a variety of different ultrafiltration modules. The information accumulated on membrane performance, membrane fouling and flux restoration techniques, and ancillary equipment performance was used to design a much larger demonstration pilot plant. This plant has been constructed and is now processing continuously each day over 1m³ of a real radioactive effluent. (author)