Development of a three-dimensional thermo-mechanical deformation model of a horizontal nuclear fuel element

Nuclear fuel of a horizontal orientation, as in a CANDU reactor, may experience deformation phenomena during irradiation known as sagging and bowing. Sagging occurs over time due to the self-weight of the pellets within the sheath, and sheath creep. Bowing occurs due to temperature gradients across the element (i.e. during dryout). In this analysis, a three-dimensional finite element model is developed of a quarter fuel element, which is equivalent to a full fuel element using symmetry, to analyze sagging and bowing of a horizontal fuel element. The model is developed using the Multiphysics Object-Oriented Simulation Environment (MOOSE) framework developed at Idaho National Laboratory. Results from the flexural rigidity analysis are presented. Code-to-code comparisons are provided for benchmarking purposes. (author)