Research progress in high-temperature thermo-mechanical behavior for modelling FeCrAl cladding under loss-of-coolant accident condition

Abstract

FeCrAl cladding has been proposed as one of the most promising accident tolerant fuel cladding candidates since the Fukushima Daiichi accident due to its excellent high-temperature mechanical properties, outstanding high-temperature steam oxidation resistance and low radiation-induced swelling rate. Cladding behavior under loss-of-coolant accident (LOCA) conditions would significantly affect reactor safety. Hence, the main focus of the present study is to provide fundamental safety analysis models for FeCrAl cladding under LOCA conditions. First, the fundamental models involved in LOCA safety analysis are identified, including high-temperature oxidation model, high-temperature failure model, high-temperature creep model, and high-temperature burst model. Second, by evaluating the research progress of high-temperature oxidation studies, the Robb model is recommended to estimate the oxidation rate of FeCrAl cladding, and the model of maximum tolerable temperature is also proposed. Then, the high-temperature creep and burst models of FeCrAl cladding are subsequently developed respectively by summarizing and reevaluating of high-temperature creep and burst data. Additionally, it has been verified that FeCrAl cladding has a much smaller burst strain than that of Zircaloy cladding, which may result in much smaller flow blockage, is verified by analyzing the deformation of FeCrAl cladding in burst experiment.