This paper presents a numerical dynamic analysis performed to estimate the maximum expected change in the mechanical vibrations of CANDU feeder pipes as a result of a change in flexural support conditions. Finite Element Analysis models are constructed to represent 480 nuclear fuel channels along with their attached inlet and outlet feeder pipes. Each of the 480 models is excited using a random white noise forcing function and the corresponding peak vibration levels are recorded. Two cases are considered to compare the vibration response with the designed support system (On-bearing) and without one support point (Off-bearing). Two types of excitations are considered; flow induced feeder bend and end-fitting excitations. The finite element results obtained from these two independent excitations are used to calculate the ratio between the feeder vibration levels with and without the west inboard end-fitting journal ring support. It is observed that the maximum increase in the expected feeders' vibration peak levels is 20% with the feeder bend excitation while only 2% increase is realized with the application of the end-fitting excitation. It is also observed that the average feeder dynamic peak response to the feeder bends excitation did not significantly change considering the full feeders population. End-fitting excitation results showed a reduction in the calculated average feeders vibration peak responses.
展开▼
