Replacement spindle, for restoration of positioning unit of fuel rod assembly at core of water-cooled nuclear reactor, has cone and shaft sections, and ring flange to be fitted under water without tapping

摘要

For the restoration of a positioning unit of a fuel rod assembly, in a water-cooled nuclear reactor, a replacement positioning spindle (28) is used with, in succession, in an axial direction, a positioning cone (28a) to fit into an opening at the lower member (15) of the fuel rod assembly, and a shaft section (28b). A ring flange (30) is between the cone and the shaft, at right angles to the axis (23) of the spindle, with a diameter equal to the diameter of a counterbore (26) at the core support plate. The spindle fits in place, under water, without tapping. The replacement spindle is secured by an elastic tubular bolt (31) through an opening (32) in the ring flange and the core support plate.