Numerical Simulation of Fatigue Crack Propagation in Nuclear Fuel Cladding Tube

The integrity of nuclear fuel cladding tubes is of great importance to ensure the safe operation of nuclear power plants. The cladding tubes operates under conditions of high temperature and pressure and experiences cyclic loads due to changes in reactor power. In this paper, a finite element analysis model of the cladding tube is established, and FRANC3D is combined with ABAQUS to numerically simulate the fatigue crack propagation on the inner surface of the cladding tube. The effects of different axial tilt angles, axial positions of cracks, and fusion of two axial cracks on the remaining fatigue life of the cladding tube are investigated. The simulation results indicate that an increase in the axial tilt angle corresponds to an increase in the remaining fatigue life of the crack. Furthermore, the cracks predominantly occur within 0–2 mm from the point of maximum stress in the cladding tube. Moreover, when two cracks merge into one, the crack propagation rate suddenly increases to a certain point, then decreases, and gradually increases again after the decrease. These research findings can provide reference guidelines for the safe operation of nuclear fuel cladding tube.