Aqueous waste which is a by-product of nuclear fuel reprocessing plants, is contaminated with tritium in the form of HTO. This waste must be disposed of in a suitable compact manner. In order to minimize waste volume, tritiated water is enriched by several orders of magnitude of its original concentration. This task is accomplished by using the existing combined electrolysis catalytic exchange (CECE)-Process, which is presently in pilot operation with tritium in a German nuclear research facility (Kernforschungszentrum Karlsruhe, KfK, FRG). Substantial energy reduction can be achieved by substituting the conventional water electrolysis by high-temperature steam electrolysis (HOT ELLY) for separating tritiated water into its components. Further and even more important advantages of implementing HOT ELLY is that the amount of radioactive inventory is minimized and no secondary waste is produced. The process engineering and safety aspects arising through the combination of the above two processes (CECE-Process and HOT ELLY) are explained.