Patent ID: 8213563

Claim:
A control rod, comprising: a tie-rod; a handle mounted to an upper end portion of said tie-rod; a connector plate mounted to a lower end portion of said tie-rod; four sheaths having a U-shaped cross-section, welded intermittently to said tie-rod at a plurality of locations of a weld portion in the axial direction of said tie-rod, extending in four directions from said tie-rod, said sheaths having an upper end in the axial direction welded to said handle and a lower end in the axial direction welded to said connector plate; and a neutron absorbing member disposed inside each of said sheaths, wherein an upper end of said weld portion located at an uppermost position in the axial direction of said tie-rod among the plurality of said weld portions between said tie-rod and said sheath in the axial direction is disposed at a position within a range between 0.8 and 13% of total axial length Ls of said sheath below an upper end of said sheath.