Tapered leaf support pin for operating plant guide tubes

摘要

A mounting system for removably mounting the lower flange of a control rod guide tube over an opening in the upper core plate of a nuclear reactor includes support pins having first and second pin portions. The first pin portion passes through the guide tube flange and has an externally threaded section. The second pin portion is secured within the bore of the upper core plate and has a solid body section and a split-leaf section. The solid body section has an outer diameter which is accommodated in the bore by a close clearance fit. The split-leaf section has a split intermediate section and a split end section. The split intermediate section extends from the solid body section, has an outer diameter which is less than the outer diameter of the solid body section, and tapers uniformly between the solid body section and the split end section to form a conical shape. The split end section biasingly engages at least a portion of the bore wall. A locking nut threadedly engages an externally threaded section of the first pin portion. A washer is disposed around the first pin portion between the locking nut and the control rod guide tube flange and includes a concave spherical upper surface which is shiftable during mounting of the locking nut to compensate for nonperpendicular alignment between the support pin and the control rod guide tube flange.