Following the Fukushima Daiichi accident, new nuclear fuel cladding designs
improving the performance and enhancing nuclear power plants' safety have been
extensively investigated. The chromium-based accident tolerant fuel cladding
coating designs were developed by ALVEL in the frame of the project sponsored
by the Ministry of Industry and Trade and UJP PRAHA in collaboration with CTU
in Prague. This study introduces a set of experiments determining a wide range
of coated cladding material properties. Metallic Cr, CrAl and multicomponent
CrN + Cr were tested, focusing on long-term corrosion resistance during normal
operating conditions, high-temperature oxidation in the steam environment and
mechanical properties during an accidental transient. All coatings revealed
enhancement in corrosion resistance when compared to Zr alloy. However, diffusion
of chromium into the zirconium substrate was observed for the metallic chromium
coatings at temperatures above Cr-Zr eutectic. Coating deposition is further
beneficial for claddings' mechanical properties. Overall, all tested coatings may be
attractive candidates as possible ATF claddings.
