Heavy water decontamination tests through a Pd-Ag membrane reactor: Water Gas Shift and Isotopic Swamping performances

Highlights: • In the HCPB blanket, helium will recover tritium in molecular and oxidised form (Q₂O). • A small amount of Q₂O has to be extracted via technologies under investigation. • A Pd-Ag membrane reactor in a new ENEA facility performed heavy water decontamination. • Two catalysts have been tested via Water Gas Shift (WGS) and Isotopic Swamping (IS). • Gas Chromatographic and FTIR analysis and comparisons have been reported in this work. - Abstract: A Pd-Ag membrane reactor has been studied to assess its ability in heavy water decontamination through Isotopic Swamping (IS) and Water Gas Shift (WGS) reactions under different operating conditions (i.e. reactor temperature, lumen pressure, feeding molar ratio and isotopic swamping). The reactor has been installed in a new facility of the ENEA Membrane Laboratory called HyFraMe, by testing two catalysts. The results are reported in terms of decontamination factor or DF (the amount of gaseous deuterium recovered from heavy water). Both catalysts demonstrate, in the WGS reactions, low methane production (1.72 mol% in the worst case) and high DF, almost 80%, at pressure of 400–500 kPa at 623 K. The IS reaction tests exhibited a lower performance (DF = 67% at the best).