Effect of hydride precipitation on the fatigue cracking behavior in a zirconium alloy cladding tube

•Ex-situ observations on crack initiation and propagation behavior are performed.•The relation between hydrides crack and the maximum principal stress is investigated.•The effect of circumferetial and radial hydrides on fatigue cracking is illustrated.•Fatigue crack propagation is facilitated along the Zr matrix-hydrides interface.•Fatigue crack nucleation and propagation proceeds along slip bands in Zr matrix.