Immobilized ion-exchange polyurethanes (IEPU) were prepared as ion conducting spacers in continuous electrodeionization (CEDI) for the treatment of a synthetic primary coolant. Ion exchange resins were immobilized by using allophanate/biuret cross-linking in preparation of polyurethane. Synthesized IEPU was characterized in terms of mechanical strength, ion exchange capacity (IEC), electrical conductivity and the porous plug model, which schematically represents the transport pattern through the IEPU. CEDI was carried out in a laboratory scale with an effective area of 20 cm². The CEDI operation with a layered bed configuration showed the main removal mechanism of cobalt ion was dependent on the active surface area between ion conducting materials. The performance of the CEDI operation showed over 98% removal of cobalt ions, suggesting the feasibility of IEPU as ion conducting spacers in a CEDI system.