Dynamics and Control of a Nuclear Refueling Machine

This paper presents an active control scheme for suppressing the vortex-induced vibrations of a nuclear fuel rod transported under water. A refueling machine (RM), which is an overhead crane, is used for transporting the rod, vertically, such that one end of the rod is fixed to the RM and the other one hangs free (i.e., in cantilever configuration). First, Hamilton's principle is used in developing a hybrid lumped-mass (i.e., the RM) and distributed parameter (i.e., the rod) model of the considered system. Then, a boundary control scheme is developed to suppress the vortex-induced vibrations of the rod by utilizing control actuation only at the top boundary (i.e., the rod/RM interface). Further, Lyapunov function-based analyses are performed to prove the uniform ultimate boundedness of the closed-loop system. To demonstrate the effectiveness of the proposed control scheme, simulations have been performed.