REPLACEMENT SUPPORT PIN FOR GUIDE TUBES IN OPERATING PLANTS

摘要

A retaining pin mounting assembly for nuclear reactor guide tubes including a pin (16) having a one end portion for disposition within a bore in the upper core plate (12) of a reactor, while the other end (24) is to extend through a bore (22) of the guide tube flange (14) and has a threaded region (30) for threadedly receiving a nut (32) provided with a locking cap (46). The pin has a flange and a shank (24) of a diameter smaller than the bore (22) with guide tube flange (14) and the nut (32) has a skirt (33) adapted to engage the flange (14) and having an inner diameter larger than the shank (24) such that an annular space is formed around the shank. Radial flow apertures 60 extend through the skirt (33) of the nut 32 so as to permit coolant flow through the annular space around the pin shank (24) in order to prevent corrosion by differences in the concentrations of the reactor coolant from that around the pin shank (24).