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A spring-and-spacer assembly for maintaining fuel rods upright in a fuel assembly of a nuclear reactor core is provided. The spring is in the form of a continuous loop with first and second legs having mid-leg rod-contact regions. Bend regions are positioned on each side of each contact region exten

A spring-and-spacer assembly for maintaining fuel rods upright in a fuel assembly of a nuclear reactor core is provided. The spring is in the form of a continuous loop with first and second legs having mid-leg rod-contact regions. Bend regions are positioned on each side of each contact region extending toward the interior of the loop spring. In most positions, the spring is used to load two adjacent fuel rods. In configurations in which there is an unpaired fuel rod, a plate having a tab for contacting the spring is provided. The spring provides the desired force, such as about 2.5 pounds per fuel rod, in a small rod-to-rod spacing of less than about 0.14 inches.

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A loop spring for maintaining fuel rods in spaced apart relation in a fuel bundle spacer, said spacer including; first and second overlying spring supporting elements for supporting a spring, said spring supporting elements disposing said spring on opposite sides to and towards a ferrule for contain

A loop spring for maintaining fuel rods in spaced apart relation in a fuel bundle spacer, said spacer including; first and second overlying spring supporting elements for supporting a spring, said spring supporting elements disposing said spring on opposite sides to and towards a ferrule for containing fuel rods, said spring elements of the type formed from a continuous elongated loop of spring material, said spring element in the unstressed state having said loop defining an upper C-shaped end in said loop for surrounding and being supported from said first spring support member from said spacer; a lower C-shaped end in said loop for surrounding and being supported from a second and underlying spacer member; paired spring leg members on either side of said loop for closing said loop between said C-shaped ends; said paired spring leg member further defining medially thereof a convex and outwardly disposed arch shaped rod contacting portion, said rod contacting portions on each of said paired spring leg members being medially located in said spring leg members between said upper and lower C-shaped sections; the improvement in said loop spring member comprising: two inwardly disposed U-shaped bends formed in either spring leg, said U-shaped bends being joined to and on either side of said convex and outwardly disposed arch shaped rod contacting portion, each said U-shaped bend being immediately adjacent said convex and outwardly disposed arch shaped rod contacting portion at one end and attached to said spring leg at the other end, each rod containing portion and said U-shaped bend on each side of said rod contacting portion defining offsets in the unstressed state of said spring from paired planes on each side of said loop spring, each said paired planes generally defined by and including the substantially linear portion of said paired spring leg members beginning at said C-shaped ends and including said paired spring leg members and ending at the beginning of said U-shaped members, said plane being defined across said rod contacting portion and said U-shaped bends on either side of said rod contacting portion so that said rod contacting portion is offset on one side of said plane away from the opposite side of said spring and said U-shaped bends on either side of said rod contacting portion are offset on the other side of said plane to and toward the center of said loop spring whereby said U-shaped bends in the stressed state of said spring expand the effective length of said spring and equalize bending stresses between said two convex and outwardly disposed rod contacting portions and said C-shaped ends.