Performance influence of polyacrylic acid dispersant on nuclear grade anion exchange resin

Abstract

Secondary circuit water chemistry control is vital for the safe operation of nuclear power plants. Polyacrylic acid (PAA) is used in the secondary circuit water system to reduce the fouling of the steam generator (SG) because of its good dispersion effect. However, PAA as a macromolecular organic matter possibly causes organic fouling for anion exchange resin of the water purification system and affects its performance. Some research reported that the performance of resin changes after PAA application. But it is not clear whether this change is related to PAA. In this research, the anion resins were performed for five cycles, and each cycle included batch PAA adsorption, dynamic PAA desorption and resin rinse. Results showed that NaOH solution could realize the desorption of PAA on anion resin, but desorption solution and rinse water consumption slightly increased with the cycle number. Meanwhile, residual PAA linearly increased with the cycle number, but the rate was relatively slow. Furthermore, the performance influence of PAA on anion resin was investigated. The exchange capacity and kinetic performance for anion resin slightly decreased after PAA cycle. The effluent conductivity of anion resin bed increased after PAA cycle, but it could not cause the adverse influence of sodium leakage. The contrast experiment of H2SO4 cycle showed that resin aging was the primary reason for the change of resin performance, rather than residual PAA. Within the fewer cycles, PAA and anion resin had better compatibility.