Integral Simulation on the Thermo-Mechanical Behavior of the UMo/Al Dispersion Fuel Plate Using Finite Element Method

Fuel plate performance under irradiation is an important topic for the research reactor. The fuel plate is expected to deform after a long-time operation, which is a threat to the reactor safety. In this research, irradiation behaviors like interaction layer growth, swelling, creep and plasticity of the UMo/Al dispersion fuel plate are carefully reviewed from literatures. Taking these behaviors into consideration, the longtime three-dimensional stress update algorithms for the fuel meat and cladding are developed respectively based on the large-deformation incremental constitutive relation. Since local properties in the fuel meat change with burnup, equivalent material properties models are used to take account of this characteristic. These models and algorithms are implemented into Abaqus user subroutines to simulate the thermo-mechanical performance of the fuel plate under the typical operating condition in research reactors. In order to illustrate the macroscopic deformation of the fuel plate and reduce the computational cost, 1/4 symmetrical geometry of the fuel plate is employed in the simulation. The evaluation and distribution of temperature, stress and deformation of the fuel plate are obtained and analyzed. Results show that the growth of interaction layer affects the temperature profiles heavily. The stress concentration mainly locates at the contact interface between fuel meat and cladding, especially at the side of the interface.