Nuclear fuel assembly spacer and spring

A spring-and-spacer assembly for maintaining fuel rods (82) in a upright preferred position in a fuel assembly of a nuclear reactor core is provided. The spring 92 has a leg portion 106 and two loop portions 116,118, one at each end of the leg. Each loop engages an ear 132,134 formed in a ferrule 136 of the spacer. Each loop contains a dimple 122,124 which contacts an ear 132,134 of the ferrule 136. The central leg portion 106 has a dimple 108, or a projection, which contacts a fuel rod 82 and biases the fuel rod against stops 148,152. The spring load is transmitted to the ferrule ears 132,134 by the dimples 122,124 in the spring loops. Preferably, the spring rotates about the dimple 122,124 when flexed, contributing to spring flexibility. The high spring flexibility permits use of the spring in connection with small rod-to-rod spacing fuel assemblies. This construction permits providing a low-mass, low-surface area spring, in turn providing for low neutron absorption and low flow obstruction.