Poly(acrylic acid-co-maleic acid), a polymer dispersant for the control of oxide deposition over nuclear steam generator surfaces

Abstract

Nuclear reactors face extended outages due to Steam Generator (SG) tube failure. Study was carried out to evaluate Poly (acrylic acid-co-maleic acid) [PAMA], as polymeric dispersant for online cleaning of SGs. The transfer of iron from carbon steel surfaces in presence of PAMA to SG tube materials viz., alloy-400 and alloy-800 in deoxygenated and alkaline conditions at 240 °C was investigated. Addition of PAMA will not only prevent the deposition on the SG tube surfaces but also help in forming a better protective inner oxide layer on the surfaces. The oxides so formed were characterised by X-ray Diffraction (XRD), Raman Spectroscopy, X-ray Photoelectron Spectroscopy (XPS) and electrochemical techniques viz., Potentio-Dynamic Anodic Polarization (PDAP) and Electrochemical Impedance Spectroscopy (EIS) to establish their protectiveness and to understand the dispersive action of PAMA. Furthermore, aqueous solution of PAMA was thermally stable besides it was also found to scavenge Dissolved Oxygen (DO).