Spacer grating for nuclear fuel element rods - has inward projections to locate rods but permit expansion

摘要

A spacer grating for a number of fuel rods combined to form a complete nuclear fuel element consists of vertically on-edge metal strips in an orthogonal pattern. Each rod is centered in the grating by lugs projecting inwards from the strips of the grating and bearing laterally against studs projecting outwards from the fuel rod. Each rod is accurately restrained in position, but is free to expand and slide relatively to the grating. The lugs bear against opposite sides of the studs. Each grating is pref. formed of upper and lower halves; the shaded lugs are attached to one half, the other lugs to the other half. With this arrangement, the two halves are positioned initially with a slight relative offsetting to facilitate the insertion of the rods and then, when the rods are in position, are brought into alignment.