A study on physicochemical properties of epoxy coating system for nuclear power plants

In this work, the thermal properties of epoxy coating system on the liner plate in the containment structure have been investigated by irradiation dose rate and design basis accident (DBA) conditions. Also, the effect of immersion in hot water on adhesion strengths of epoxy coating system has been studied. The glass transition temperature (Tg) and thermal stability of the epoxy coating system after DBA tests were measured by differential scanning calorimeter (DSC) and thermogravimetric analyser (TGA) analyses, respectively. Contact angle measurements were used to determine the effect of immersion on the surface energetics of epoxy coating system, including surface free energy and work of adhesion. Adhesion tests were also executed to evaluate the adhesion strength at interfaces between carbon steel plate and epoxy resins. As a result, the DBA test led to the improvement of the internal structure in cured epoxy systems, resulting in significantly increasing the thermal stability, as well as the Tg. Also, the immersion in hot water had a role in the post curing of epoxy resins and increased the mechanical interlocking of the network system, resulting in increasing the adhesion strengths of the epoxy coating system.