Modeling of Fuel Bundle Vibration and the Associated Fretting Wear in a CANDU Fuel Channel
NURETH-14 - 2011 September 25-30

Presented at:
2011 September 25-30
Toronto, Canada
Session Title:
A7-1 Mini Symposium on Flow-induced Vibration in Nuclear Components

Atef Mohany (University of New Brunswick)
Marwan Hassan (University of New Brunswick)


In this paper a numerical model is developed to predict the vibration response of a CANDU

® fuel

bundle and the associated fretting wear in the surrounding pressure tube. One excitation

mechanism is considered in this model; turbulence-induced excitation caused by coolant flow

inside the fuel channel. The numerical model can be easily adapted to include the effects of

seismic events, fuel bundle impact during refuelling and start-up of the reactor, and the acoustic

pressure pulsations caused by the primary heat transport (PHT) pumps. The simulation is

performed for a typical CANDU fuel bundle with 37 fuel elements. The clearances between the

buttons of the inner fuel elements, and between the bearing pads of the outer fuel elements and

the pressure tube were measured from an actual fuel bundle. Some variability among the

measured clearance values was observed. Therefore, probability density functions of the

measured clearance values were established and the simulation was performed for the

probabilistic distribution of the clearance values. The contact between the fuel bundle and the

pressure tube is modeled using pseudo-force contact method. The proposed modelling technique

can be used in future CANDU reactors to avoid fuel and pressure tube fretting damage due to the

aforementioned excitation mechanisms.

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