Validation of a multimodal set-up for the study of zirconium alloys claddings' behaviour under simulated LOCA conditions

In a previous paper, Campello et al. presented a combined experimental/numerical approach to identify the creep behaviour of as-fabricated Zircaloy-4 claddings under simulated LOCA conditions. The current paper deals with the uncertainties and errors estimation of the two key methods used to measure the thermal and kinematic full fields during the creep tests: near infrared thermography (NIRT) and two-dimensional digital image correlation (2D-DIC). The NIRT uncertainties are evaluated as 0.7% of the actual temperature. They are mainly due to the thermocouple measurements used to calibrate the radiometric model of the NIRT. A combined 2D-DIC/edge detection approach is proposed to quantify the error related to 2D-DIC when measuring the ballooning of the tubular specimen. The 2D-DIC error is evaluated as 0.1% of the actual equivalent strain even for ballooning inducing a radius increase of 20%.