Behavior of high burnup fuels under Reactivity-Initiated Accident (RIA) and Loss-of-Coolant Accident (LOCA) conditions, 6; Fracture conditions of fuel rods in a LOCA

Nagase, Fumihisa ; Chuto, Toshinori; Hatakeyama, Yuichi; Fuketa, Toyoshi

LOCA-simulated experiments were conducted with irradiated PWR and BWR fuel cladding (77 GWd/t) to investigate high burnup effect on LWR fuel behavior under LOCA conditions. In the experiments, MDA, NDA, ZIRLO, M5 and Zircaloy-2 cladding specimens were sampled from the high burnup fuels irradiated at European power plants, and they were oxidized at 1563 to 1480 K and quenched. The cladding specimens oxidized to 18.3 to 27.3% ECR did not fracture during the quench. Consequently, the fracture boundary is not significantly reduced in the examined burnup range. Obvious high burnup effect was not seen also in the ballooning, rupture, fracture behavior.