Abstract: A fuel bundle positioning and ejecting apparatus comprising two piston members, one slidable along a stem on the other piston member, and a compression spring urging the pistons apart, is secured in a horizontally extending fuel channel upstream of the coolant flow therealong. The downstream one of the piston members has a shield plug attached thereto and the piston members are urged together in a fuel channel with he compression spring compressed, by a series of fuel element bundles along the fuel channel. When the downstream end of the fuel channel is opened using a fuelling machine, with pressurized coolant therein and continued circulation of coolant along the fuel channel, the compression spring expands causing the piston members to become entrained in the coolant and urge the fuel element bundles out of the fuel channel and into the fuelling machine.