Ductile tearing criteria and failure probability estimation of hydrided Zircaloy-4 cladding under axial loads

To maintain a safe management of spent nuclear fuel (SNF), it is necessary to understand the characteristics of fuel cladding associated with material degradation and failure criteria. This study aims to establish strain-based failure criteria for Zircaloy-4 cladding from uniaxial tensile tests considering hydride distribution. An investigation of the hydrogen effect on mechanical properties of cladding was presented using the design of experiment method. The applicability of the proposed criteria for transverse tearing failure mode was demonstrated in energy-limited events using finite element analysis. The failure probabilities of cladding were estimated for normal transportation and hypothetical accident conditions. The proposed failure criteria provide an advancement on the existing studies that only implemented transverse tearing failure mode by considering hydride distribution. This effort could be particularly valuable to the regulatory institutes and those utility planners who are evaluating structural integrity concerning the critical characteristics of SNF for potential licensing considerations.