Development of specific software for hydrogen isotopes separation by cryogenic distillation of ICSI Pilot Plant

•“In-house software” developed and used for the design and simulation of multicomponent distillation column with multiple feed and extraction.•Multiple feed and extraction points H2 cryogenic distillation column design and simulation.•Mathematical model for design and simulation of H2 cryogenic distillation process. ITER Isotope Separation System (ISS) is based on cryogenic distillation process and is one of the main systems within the ITER Fuel Cycle. Similar to ITER ISS, one of the key systems of a detritiation plant for low level tritiated light or heavy water is the cryogenic distillation. Provisions are being made in ICSI to design and build an experimental facility based on CECE (Combined Electrolytic Catalytic Exchange) process coupled to a cryogenic distillation system able to process these kinds of waters. The aim of this work is to present the results of the design and simulation activities in support to the development of a cryogenic distillation system capable to achieve the required decontamination factor and tritium enrichment better than 90 %. This is done by using a software developed “in house”, based on heat and mass transfer model. Based on the input data like, flow rates, composition of the feeding gas, pressure drop, the simulation provides the distribution of all the molecular species involved, temperature profile and also the liquid and vapor enthalpies along the column. The results may provide useful information for the ITER ISS decontamination factor during dynamic operation due to the ISS transient feed flow rate coming from the WDS (Water Detritiation System).