Fuel assembly

Object: To permit ready and safe mounting and removal of fuel rods to and from the upper tie plate by fitting a rotary engagement member capable of engaging with the upper tie plate in the tie rod of the fuel rods. Structure: The upper tie plate is raised against a rod spring mounted on a tie rod, thereby preventing the rise of the upper tie plate in a stop section. Then, the rotary engagement member which is in pressure contact with a stopper rotates to bring the check section into engagement in a notched groove formed in the upper tie rod, to thereby render the upper tie plate removable. In this way, the upper tie rod may be removed from the fuel rods without separating various parts provided on the tie rod from the same but by only simple operation of a single part. (Kamimura, M.)