Review on chromium coated zirconium alloy accident tolerant fuel cladding

The Fukushima-Daiichi accident revealed that the zirconium fuel claddings have the significant safety risk of hydrogen detonation due to the strong oxidation and hydrogen release during the design basis accidents (DBA) and beyond design basis accidents (BDBA). Therefore, research and development of accident tolerant fuel (ATF) concepts that aim to improve nuclear fuel safety during normal operation, operational transients and possible accident scenarios have been boosted in the last decade. Deposition of protective coatings on Zircaloy cladding tubes has been considered as a near-term solution of enhanced ATF cladding. Among the candidate coating materials, there is no doubt that the research progress of Cr coating is the fastest around the world because of the advantages of such type of coating: excellent good chemical stability (including oxidation resistance and hydrothermal corrosion resistance), low thermal neutrons absorption cross-section, and excellent adherent. In this paper, the oxidation, diffusion, and mechanical properties of Cr-coated Zr alloys in normal operation conditions and accident conditions of nuclear reactors are reviewed. ... mehrThe factors that cause the failure of the coating are analyzed, and some questions that need to be clarified and further studied are proposed.