Modelling of fully-flexible fuel bundles

摘要

This work presents an analytical framework to model fully flexible fuel bundles. The model is capable of predicting the vibration response of fuel bundles with a large number of elements and various end conditions, such as flexible endplates. The fuel bundle and the supporting structure were modelled utilizing finite beam and plate elements. The contacts between the system components, such as fuel-to-fuel and fuel-to-boundary, were modelled using the single point contact method (SPC). Fluid excitations, such as turbulence, pressure pulsation, and fluidelastic forces, were modelled. The results of the model were compared with the available experimental data. This framework was utilized to study the dynamics of CANDU fuel bundles. The investigation included fretting wear parameters, such as response, impact force, and normal work rates. In addition, a prediction was made of the stresses on the endplates due to the vibration of the tubes. The results revealed that endplate cracking can arise as a result of the aforementioned excitation mechanisms.