Nuclear fuel rod loader for pulling fuel rods into a fuel assembly skeleton

Claim 1

In a nuclear fuel rod loader for pulling a nuclear fuel rod from a fuel rod magazine into spacer grids of a nuclear reactor fuel assembly skeleton, a nuclear fuel rod gripper for releasably engaging an internal circumferential groove of a nuclear fuel rod end plug cavity, said gripper comprising: (a) an outer tube having an end portion, said end portion having a plurality of longitudinal slots each having a closed slot end and an open slot end, said slots defining fingers therebetween, said fingers each having inwardly-biased finger ends, said inwardly-biased finger ends each having a generally outwardly-projecting rim portion, said rim portions together defining a generally circular and circumferential rim, said rim longitudinally insertable into said nuclear fuel rod end plug cavity; and (b) an inner shaft insertable in said outer tube, said inner shaft having a terminus portion, said terminus portion longitudinally engagable with said inwardly-biased finger ends to spread them apart to open said rim for said rim portions to releasably engage said internal circumferential groove of said nuclear fuel rod end plug cavity; and wherein the outer surface of said outer tube is connected to the inner surface of said outer tube at said closed slot end of each said slot by a transition surface, each said transition surface including a generally outwardly-facing, longitudinally-running, chamfer surface and a generally open-slot-end-facing stress relief surface, with said chamfer surface coextensive with said outer surface of said outer tube and said stress relief surface coextensive with said inner surface of said outer tube, wherein said chamfer surface has a radially-transverse depth and a longitudinal length, with said radially-transverse depth smaller than said longitudinal length, and wherein said stress relief surface has a stress relief radius.