Microstructure and hydrogen content of electrodeposited chromium coating on the inner surface of EP823-SH steel cladding

To reduce corrosion damage to the inner surface of ferritic-martensitic steel fuel rod claddings, additional measures must be taken to increase the corrosion resistance of this steel. One potential approach is applying a chromium coating to the cladding's inner surface. This study investigates the microstructure and hydrogen content of chromium coatings electrodeposited onto the inner surface of fuel rod cladding tubes (internal diameter: 8.7 mm). Under the tested conditions, an electrolyte temperature of 30–35 °C yielded crack-free, equiaxed coatings at a current density ≤ 0.2 A/cm 2 . Higher electrolyte temperatures produce coatings with a columnar structure. Hydrogen accumulation of ∼2 at.% was observed in coatings deposited under optimal conditions. Annealing chromium-coated claddings at 420 °C enables complete hydrogen degassing. Consequently, hydrogen uptake during the chromium plating process will not degrade the cladding's original performance characteristics.