Thermally Induced Deformations in Nuclear Fuel Elements
thesisposted on 23.05.2021, 15:11 by Haihui (Stella) Yang
Nonlinear three-dimensional multibody surface-surface contacts, thermally induced deformations, and the curvature transfer factor in CANDU fuel elements are investigated using the finite element method in this thesis. ANSYS is selected to obtain numerical solutions for CANDU fuel elements under several operating conditions. In the ANSYS models, the 20-node structural elements (SOLID186) are employed to mesch individual solids; the surface-to surface contact pairs (TARGE170 and CONTA174) are used to handle contacts between solids. Sensitivity studies on the curvature transfer factor are conducted for several key operational parameters. If there is full radial contact between the pellets and the sheath, a CANDU fuel element may be considered as a composite beam because of the large length-to-diameter ratio. The Timoshenko beam theory is used in conjunction with a three-node mean element to explore the thermal deformation behaviours of a fuel element. A program written in MATLAB is much more efficient compared with the ANSYS solutions.