Experimental characterization of the dynamic response of a mock-up CANDU fuel bundle

Abstract

This thesis discusses the vibration response of a mock-up CANDU 37M fuel bundle. The experiments are performed using non-invasive methods of vibration measurement by means of high-speed cameras and laser displacement sensors. The contact dynamics between the fuel bundle and the pressure tube are replicated using a high precision custom-made setup. Also, the contact between the fuel bundle and the neighboring fuel bundles are replicated using dummy endplates. The results show that the fundamental frequency of the fuel elements changes depending on the contact conditions with the neighboring fuel bundles. Furthermore, the endplates exhibit a complex vibration response with multiple dominant vibration frequencies that include the fundamental frequency of the fuel rods. The results of this experimental work provide a consistent and accurate characterization of the damping ratios and mode shapes of the fuel rods and the whole bundle including the endplates.