A Three Dimensional Finite Element Analysis of a CANDU Fuel Element

A three-dimensional treatment has been developed using ABAQUS finite-element software to model the thermal-mechanical behavior of a CANDU nuclear reactor fuel element. This model couples the heat transfer characteristics with the mechanical behaviour of the UO2 fuel pellets and sheath, and accounts for the interaction effects which arise due to contact between the fuel pellets and sheath and the adjacent fuel pellets. This analysis therefore provides a means to describe the structural deformation of a fuel element that may occur during in-reactor operation. The objective of this work was therefore to assess the capability of the ABAQUS software suite to specifically model such deformation behavior.;Due to memory limitations, a half-size fuel element could only be simulated in this work with ABAQUS installed on the High Performance Computation Virtual Laboratory (HPCVL). The model was successfully benchmarked against an analytical beam calculation by applying a load at the mid-point axial position in order to predict the deflection of the fuel element. This treatment was also validated against temperature predictions derived from the ELESTRES-IST fuel performance code. The model was further used to assess the flexural rigidity of a fuel element with and without the occurrence of contact between the fuel pellets and sheath. The limitations of the software suite are discussed in this work. Despite these limitations, the ABAQUS software suite shows promise for simulating the thermal and mechanical characteristics of a CANDU fuel element in a complete three-dimensional representation.