Analysis of the fracture behavior of hydrided fuel cladding by fracture mechanics

In order to elucidate the fracture behavior of light water reactor (LWR) fuel rods under reactivity initiated accident (RIA) conditions, an analysis based on fracture mechanics has been performed for several types of hydrided cladding tubes. Fracture mechanics parameters such as stress intensity factor (SIF), J-integral and plastic yield load were estimated by finite element method (FEM) analysis, and the failure assessment diagram (FAD) was constructed using the fracture mechanics parameters to estimate the failure stress of the claddings. It was found from the FAD that the predicted fracture stress of the claddings was qualitatively consistent with the experimental results obtained by pulse irradiation tests in the Nuclear Safety Research Reactor (NSRR) and high-pressurization-rate burst tests at Japan Atomic Energy Research Institute (JAERI).