The most common basic process of air detritiation employing oxidation of tritiated gases in a catalytic recombiner and subsequent collection of HTO on molecular sieve driers can also be used for a large scale detritiation system for the next step DT fusion device. Performance, economy and reliability can be improved by modifying the design of basic elements ie recombiners and molecular sieve driers, and by re-arranging them in a system permitting multiple process path choices for optimum performance depending on demand. The proposed system is shown to be: ­ free of secondary tritium releases by permeation, ­ economical, with less than 1KW power required in a ready-to-operate "Hot Standby" condition, ­ capable of reducing inlet humidity in the order of 10.000ppm (Volume) to 0.01ppm at the outlet by using two adsorber stages in series, ­ capable of providing the best starting condition for water processing: little or no dilution by H2O from isotopic swamping due to use of two adsorber stages. The system detritiation factor DF is defined and discussed, demonstrating the overriding importance of high water retention efficiency.