Abstract: In order to facilitate refueling operations, cables, which provide control and power linkages between control element drive mechanisms (CEDMS), and a terminal panel supported on a side wall of the reactor cavity, are disposed in a cylindrical extension of a cylindrical enclosure which encloses the CEDMS, with sufficient slack that they can be drawn out of the cylindrical extension through windows and supported on a drawbridge type of arrangement comprised of pivotal window tray type structures which are respectively hingedly connected to the cylindrical extension and either the wall or the terminal panel, and which span the gap between the cylindrical extension and the terminal panel when pivoted to their respective supporting positions.