Research progress in high-temperature thermo-mechanical behaviors for modelling Cr-coated cladding under loss-of-coolant accident condition

Chromium (Cr)-coated zirconium cladding has emerged as a leading candidate for accident tolerant fuel (ATF) cladding in near-term engineering applications. This cladding demonstrates enhanced resistance to high-temperature oxidation, superior mechanical properties at elevated temperatures, and a relatively high level of technological maturity. Its performance under loss-of-coolant accident (LOCA) conditions is critical to reactor safety, making it a key focus of the present study. The present work introduces an overview of research progress on high temperature thermo-mechanical behaviors for Cr-coated cladding and provides a set of fundamental safety analysis models tailored for LOCA scenarios. First, essential models for LOCA safety analysis of Cr-coated cladding are identified, including a high-temperature oxidation model (along with a Cr coating consumption model), a high-temperature creep model, a high-temperature burst model, and an embrittlement criterion. Second, based on the evaluation of experimental data from high-temperature oxidation studies, models for the growth of Cr₂O₃ layer and oxygen absorption are recommended to estimate the oxidation rate of Cr-coated cladding. Additionally, a model for Cr coating consumption is proposed. Subsequently, through a comprehensive review and reevaluation of high-temperature creep and burst data, corresponding models for Cr-coated cladding are developed respectively. Finally, embrittlement data for Cr-coated cladding are analyzed, and embrittlement criteria for both one-sided oxidation and two-sided oxidation conditions are proposed.