Spring assembly for biasing fuel rods in adjoining ferrules and spacer formed of the ferrules and spring assemblies

摘要

Spring assemblies (52) are employed in adjoining ferrules (50) of a spacer (24) in a nuclear fuel bundle to bias the fuel rods against stops and hence position the fuel rods in the spacer. The spring assemblies (52) in one form include back-to-back spring bodies (56a,56b) having central leaves (58) with forward projections (64) extending through rectilinear openings (82) in adjacent ferrules to engage fuel rods to bias the rods against stops at the opposite sides of the ferrules. Outer pairs of leaves (60) straddle the central leaf (58) and project rearwardly and join the spring bodies (56a,56b) one with the other whereby the central leaves (58), end portions (62) of the springs connected to the central and outer leaves, and the outer leaves (56a,56b) act as paired springs in series, providing a low spring constant. In another form, a single spring body (88) has a central leaf (90) with a projection (96) extending through an aperture (102) of a ferrule (100) to bias the fuel rod. The outer leaves (94) bear against the outer surface of the adjoining ferrule. In this latter form, pins (106) may be used to compress the springs to facilitate insertion of the fuel rods into the ferrules.