Modeling lateral contact constraints among CANDU fuel rods

An effective procedure based on the linear complementary problem (LCP) formulation is presented in this paper to deal with lateral contact constraints among a system of closely packed and parallel fuel rods at a cross section where spacer pads and bearing pads are introduced. The total number of potential contact constraints exceeds the number of available degrees of freedom (DOF's). Numerical results for an example application involving deformations of seven rods at the midspan cross section indicate that the proposed procedure is accurate and robust. The scheme is currently being implemented into a computer code for computing vibration of CANDU®2 fuel bundles under normal operating conditions.

► Developed a node-to-node (NTN) scheme for handling large number of internal and external unilateral contact constraints.
► Demonstrated the proposed scheme is accurate, robust and applicable to CANDU fuel bundles in a pressure tube.
► The scheme can be used with the beam model of CANDU fuel rods for efficient simulation of bundle vibration.