Simulation of the thermomechanical effects originated on a fuel pin with a creacked pellet by different power ramp velocities, using a two dimensional finite element model

Abstract

Thermomechanical effects originated on a fuel pin with a cracked pellet by different power ramp velocities has been studied. To such purpose, the response of a simplified two dimensional finite element model including viscoelastic properties on the pellet and elastoplastic properties on the clad was investigated, under the influence of various ramps with durations ranging from 0 s (instantaneous ramp) to 200 s (slow ramp).The importance of both, the viscoelastic relaxation effects and their interaction with the plastic behaviour of the clad was put in evidence. It has been observed, that the mechanical response of this fuel pin model strongly depends on the ramp's duration.