Measurements of delayed hydride cracking propagation rate in the radial direction of Zircaloy-2 cladding tubes

► The delayed hydride cracking (DHC) velocity of Zircaloy-2 was measured. ► The velocity followed the Arrhenius law up to 270 °C. Activation energy was 49 kJ/mol. ► The threshold stress intensity factor for the DHC was from 4 to 6 MPa m1/2. ► An increase in material strength accelerated the DHC. ► Precipitation and fracture of hydrides at a crack tip is responsible for the DHC.