Locking fastener for securing components in a nuclear reactor

A threaded fastener includes a head, a threaded shank extending from a bottom face of the head along a longitudinal axis of the fastener, and an annular flange oriented transverse to the longitudinal axis and surrounding the bottom face of the head. A surface has a receiving hole in which the shank of the threaded fastener is disposed with the bottom face of the head contacting the surface. The surface further has a crimping recess spaced apart from the receiving hole. A portion of the annular flange overlaps and is deformed into the crimping recess. The fastener may be a screw or bolt. In the case of a bolt, a nut engages the distal end of the threaded shank. The nut also includes an annular flange that is deformed into a crimping recess on a surface proximate to the nut.