Preparation and properties of water-soluble coatings resistant to scratching on the surface of nuclear cladding

•A water-soluble coating was prepared on the surface of nuclear fuel rods.•The coating has optimized scratch resistance.•The water contact Angle of coating is 32.78o after adding neutralizer and filler.•Ethanolamine, polyacrylic acid and quartz sand improves the scratch resistance of coating. As the second barrier of radioactivity in the reactor core, Zr alloy nuclear cladding tubes are easily to be scratched by the fixed grid during assembly process. In order to protect them from possible damage during their insertion through the skeleton, it is proposed to use water-soluble coatings with excellent scratch resistance to protect nuclear cladding tubes, and then wash away the coating to prevent the impeding the normal operation of the assembly. In this study, polyacrylate emulsion, neutralizer and filler were used to synthesize the coating. The chemical composition, thermal stability and hydrophilic performance of the coating were analysed by Fourier Transform Infrared Spectroscopy (FT-IR), thermal gravimetric analysis (TGA) and water contact angle (WCA) respectively. TGA analysis showed that the weight loss rate of the coating was less than 10 % at 200 °C, indicating the good thermal stability of coating at 200 °C. The water contact Angle of the coating was reduced to 32.78°, indicating that the coating had good hydrophilicity. Scanning electron microscopy displayed that the micro-structure of coating was dense, which was one reason of the good scratching resistant. By adjusting the curing conditions, the optimized preparation parameters of the coating were obtained. When the curing temperature was 90 °C and the curing time was 30 min, the coating had more optimized scratch resistance and water solubility.