Multiple-pass photoreactor for laser isotope separation of tritium

As much as 10/sup 6/ Ci of tritium is expected to be released annually in the effluent water from a nuclear fuel reprocessing plant that will be constructed in the next ten years in Japan. While many conventional hydrogen isotope separation processes are considered for the recovery of this tritium, laser isotope separation is believed in principle to have the advantage for this application, since the energy required for separation is directly related to the laser beam absorption by tritiated molecules present in the ppm level, while major untritiated molecules are unaffected. Tritium isotope separation by CO/sub 2/ laser-induced multiphoton dissociation was first demonstrated by the author's group, and the selectivity increased dramatically afterward. Among the several working substances we found, chlorotetrafluoroethane was found to yield very high T/H selectivity and low dissociation threshold. A new continuous-flow photoreactor with multiple-beam reflection was designed for this molecule. The design procedure of this photoreactor was experimentally validated