Abstract: [Background] The solid polymer tritium electrolysis enrichment method is the mainstream to concentrate low-level tritium water. Its performance depends on whether it can obtain high tritium recovery. As the volume concentration factor is constant, the tritium separation coefficient determines the value of tritium recovery. [Purpose] This paper aims to enhance the tritium recovery of solid polymer electrolysis tritium enrichment system and improve the performance of tritium enrichment system. [Methods] The separation coefficient was adopted as an index to optimize the solid polymer tritium enrichment system on cathode and anode materials, electrolytic current and electrolysis temperature. [Results] With the initial volume ≥ 400 mL, the current of electrolytic water electrolysis device at 15 A, the temperature at 5℃, electrolysis residual volume ≤ 25 mL, we have been obtained the optimized tritium separation coefficient of 6.5, the tritium concentration system recovery factor ≥ 65%. [Conclusion] The performance of solid polymer electrolysis tritium enrichment system almost achieves international level.

Key words: Solid polymer electrolysis tritium enrichment, Tritium recovery factor, Separation coefficient, Electrocatalysts, Membrane electrode assembly