Inspection of the turbine coupling bolt holes showed extensive damage resulting from repeated installation and removal of conventional coupling bolts, indicating ,considerable lost time during previous outages.
To prevent repeating this issue the Nuclear Corp of India specified PILGRIM Radial Fit Bolts and CHAT tools on the HP-LP!; LP1-LP2; LP2-Generator.
PILGRIM Radial Fit Bolts were selected for the coupling bolts. The Radial Fit Bolts have an outer sleeve with a tapered bore, the outer sleeve diameter is parallel, which expands when the bolt is hydraulically actuated to draw the taper shank bolt in to the matching sleeve, creating a true interference fit between the bolt sleeve and coupling. resulting in assembly in 10 minutes.
In addition the CHAT tool was purchased to assist with quick coupling alignment, resulting in accurate alignment within 15 minutes.