The simulation of the units for hydrogen isotope separation by cryogenic distillation with packed columns can be carried out with a very efficient tool based on a non equilibrium model [1]. This new approach enables a better representation of the physical phenomena involved in the columns to be obtained and consequently, better accuracy for the tritium inventory in the whole process. At the TSTA facility, one of main systems is the Isotope Separation System (ISS), fitted with an on-line laser Raman spectroscopy system : it allows to obtain very accurate composition profiles in the columns, rapidly and safely. Using experimental data, provided by TSTA, CEA, associated with PROSIM S.A., have carried out calculations on column 1. This study clearly demonstrates :

  1. - the high efficiency of the experimental device.
  2. - the good accuracy of the results in comparison with experimental data (composition profiles).
  3. - the powerful of the method for design activities.