The effect of fuel rod oxidation on PCMI-induced fuel failure

► We examined Zry-4 oxide thickness and oxidation-induced failure root cause. ► Some fuel rods having greater than about 120 μm oxide were failed. ► Failed rods showed several axial cracks on the outer cladding surface. ► Axial cracks were generated by PCMI-induced stresses during a power ramp. ► Peak PCMI stresses were estimated by considering pellet-clad friction coefficients.