The mass transfer parameters of Liquid Phase Catalytic Exchange (LPCE) column have been evaluated as a part of conceptual design study of a water detritiation facility for JET. Height of Transfer Unit (HTU), Height Equivalent to Theoretical Plate (HETP) and overall mass transfer coefficient (KG) were evaluated for tritium and deuterium isotopic exchange between gaseous hydrogen and liquid water using the LPCE column operated with the same three-isotope mixture. The HTU and KG were the same for tritium and deuterium. This indicates that mass transfer in gaseous phase and isotopic exchange reaction limit the overall mass transfer rate in the LPCE column. However, a deviation from this behaviour has been observed for the small water load to the column.