Water – hydrogen catalytic isotopic exchange is the front-end detritiation technology that is used in the pilot plant at ICSI Rm. Valcea. It is also chosen as the main technology for the Tritium Removal Facility will be built at the Cernavoda NPP, Romania. The performance of the isotopic exchange process is mainly determined by the composition of the packing used in the catalytic isotopic exchange columns of the installations. In order to have a good working the packing should consist out of two components: i) a catalyst to enable the isotopic exchange and ii) a hydrophilic packing to maximize the fluid surface that can participate in the isotopic exchange. It is important that these two components of the packing are arranged in such a way that a uniform flow along and across the exchange column is ensured. To achieve a high performance packing theoretical and experimental research that took several years was necessary. The impact of the catalyst /hydrophilic packing ratio, the structure of these materials and their mutual arrangement were investigated. Theoretical analyses based on mathematical models contributed were used to select the optimal exchange column compositions for experimental research. This paper presents a theoretical analysis developed to set up a high performance catalyst-packing mixture, as well as the developed graphical and numerical mathematical models that allowed for this analysis.