Lithium Uptake on Fe-Saturated Resin at CANDU PHTS Purification Conditions

Abstract

The use of ion exchange (IX) resin to remove ionic impurities from solution is prevalent in industrial process systems, including in the primary heat transport system purification circuit of nuclear power plants. Despite its extensive use in the nuclear industry, our general understanding of ion exchange cannot fully explain some of the complex chemistry in IX beds, particularly when operated at their saturation limit. This work investigates the behaviour of mixed-bed IX resin, saturated with species representative of corrosion products from a CANDU PHTS, particularly with respect to the removal of Li⁺ ions from solution and the resulting effect on system pH. Experiments were performed under reducing conditions, representative of normal operation. The results show interesting iron chemistry, suggesting the hydrolysis of cation resin-bound Fe species and their subsequent removal as a solid hydrolysis product or as the soluble, anionic Fe(OH)_3^-.