Commissioning of Water Detritiation and Cryogenic Distillation Systems at TLK in View of ITER Design

The Water Detritiation System (WDS) of ITER is one of the key systems to control the tritium content in the effluents streams, to recover as much tritium as possible and consequently to minimize the impact on the environment. In order to mitigate the concern over tritium release into the environment during pulsed operation of the Torus, the WDS and Isotope Separation System (ISS) will operate in such way that WDS will be a final barrier for the processed protium waste gas stream discharged from ISS. The ITER ISS consists of a cascade of four cryogenic distillation columns with the aim to process mainly two gas streams, one from Torus exhaust and other from WDS mixed with the returned stream from Neutral Beam Injectors (NBI). The behavior of the CD cascade has to be characterized with high accuracy with respect to thermal and isotopic fluctuations during Torus pulses. To support the research activities needed to characterize the performances of various components for WDS and ISS processes in various working conditions and configurations as needed for ITER design, an experimental facility called TRENTA based on the combination Combined Electrolysis Catalytic Exchange (CECE) - Cryogenic Distillation (CD), representative of the ITER WDS and ISS protium separation column, is under full commissioning at TLK. The CECE process consists of a solid polymer electrolyser unit as envisaged to be used in ITER WDS, and an 8 m Liquid Phase Catalytic Exchange Column (LPCE). The Electrolysis unit was commissioned with tritiated water and the enrichment factor was measured. The experimental program on the Cryogenic distillation facility at TLK is conducted to provide the necessary design and operation information for ITER ISS. It is focused on two major issues: - To investigate the separation performances and liquid hold up of different packings in cryogenic distillation process and to validate the steady-state mathematical modeling of the process. - To investigate the CD process during isotopic and thermal transitory regimes. The experimental data obtained on TRENTA facility will allow the dynamic modeling code to be improved and benchmarked against ITER relevant operation conditions. The refrigeration unit of 250 W capacity at 16 K was commissioned and tests related to separation performances of a 3 m CD column are on-going. (author)