Stress analysis of aspherical TRISO-coated particle with X-ray computed tomography

Abstract

The failure probability of TRISO-coated particle is directly dependent on the asphericity and the layer thickness. Local asphericity of the SiC layer will contribute to the concentrated stress region, increasing failure probability of the particle. In this paper, we utilized micro X-ray computed tomography (CT) to obtain the 3D volume rendering of the SiC layer with the real geometric shape before irradiation. The stress distribution of the aspherical reconstructed SiC was then simulated with finite element method (FEM) based on the pressure vessel model. The maximum and mean principle stress were compared between the analytical methods and FEM simulation. The maximum deviation between the SiC principle stress with the real shape and ideal shape is 64.56 % for the inner gas pressure 17 MPa. The preliminary failure probability using the aforementioned stress was calculated and compared with the analytical solution. There is obvious increment with the maximum principle stress. The local stress concentration of the acquired aspherical model is 1.86. The stress discrepancy between the FEM simulation and the theoretical calculation increases with the inner gas pressure. The SiC asphericity measured with X-ray CT will contribute to a higher failure probability under irradiation.

Keywords

• Stress analysis
• Aspherical TRISO
• X-ray CT
• Finite element method