Removal of Co²⁺ and Sr²⁺ from a Primary Coolant by Continuous Electrodeionization Packed with Weak Base Anion Exchange Resin

The rapid development of the nuclear power plant (NPP) in China leads to increasing attention to the minimization of radioactive waste. The primary coolant is one of the sources of low-level radioactive wastewater and must be decontaminated before its discharge to the environment. One of the possibilities is by means of continuous electrodeionization (CEDI) technology. In this paper the lab-scale experiments demonstrate that CEDI can offer favorable decontamination of primary coolant in NPP, with minimized radioactive spent resin production. Displacement of the anion exchanger by weak base anion exchangers in a CEDI module can improve the Co²⁺ and Sr²⁺ removal. In the dilute effluent of the modified module, Co²⁺ and Sr²⁺ concentrations are below 2 ngl-1 and 58 to 114 ngl-1 , respectively, which is much lower than the commercial one of 205 to 289 ngl-1 and 268 to 326 ngl-1 . This displacement has a negligible influence on the electrical resistance of the module.