A nuclear fuel assembly having a top end fitting and a bottom end fitting connected together by a structural assembly having an axial dimension that extends from the bottom end fitting to the top end fitting, the top end fitting having a spring assembly projecting above an upper surface of the top end fitting, the spring assembly comprising: a primary spring member extending above the top end fitting, including a first straight leg portion extending from a point of attachment proximate one end of the primary spring member with the one end attached to a frame of the top end fitting at an acute angle to a plane orthogonal to the axial dimension, with the acute angle greater than zero degrees, an arcuate transition portion at the other end of the first leg, and a straight second leg portion extending from the transition portion toward the frame at an acute included angle with the first leg, the primary spring member being oriented on the top end fitting so that the transition portion is at the vertical highest elevation, whereby movement of the end fitting and an upper plate of a reactor that the nuclear fuel assembly is designed to operate in, relatively toward each other primarily loads the transition portion and deflects the first leg portion about the attachment to the top end fitting frame; at least one secondary spring having a first and second end, the first end attached to the top end fitting adjacent the first end of the primary spring first leg, and the second end terminating adjacent the transition portion, and means at the second end of the secondary spring for interacting with the transition portion to resist downward movement of the transition portion as the primary spring member deflects in a cantilever fashion; wherein the one end of the primary spring that is attached to the frame of the top end fitting is clamped on a first portion of a surface on the frame that extends substantially at the acute angle, a periphery of the first portion of the surface of the frame under the primary spring being radiused to transition to a second portion of the surface of the frame under the primary spring that extends substantially parallel to the plane orthogonal to the axial dimension; characterized in that said at least one secondary spring is in the form of a straight flat beam that extends from said first end to an intermediate portion near said second end where the flat beam is radiused in the direction of the frame. a primary spring member extending above the top end fitting, including a first straight leg portion extending from a point of attachment proximate one end of the primary spring member with the one end attached to a frame of the top end fitting at an acute angle to a plane orthogonal to the axial dimension, with the acute angle greater than zero degrees, an arcuate transition portion at the other end of the first leg, and a straight second leg portion extending from the transition portion toward the frame at an acute included angle with the first leg, the primary spring member being oriented on the top end fitting so that the transition portion is at the vertical highest elevation, whereby movement of the end fitting and an upper plate of a reactor that the nuclear fuel assembly is designed to operate in, relatively toward each other primarily loads the transition portion and deflects the first leg portion about the attachment to the top end fitting frame; at least one secondary spring having a first and second end, the first end attached to the top end fitting adjacent the first end of the primary spring first leg, and the second end terminating adjacent the transition portion, and means at the second end of the secondary spring for interacting with the transition portion to resist downward movement of the transition portion as the primary spring member deflects in a cantilever fashion; wherein the one end of the primary spring that is attached to the frame of the top end fitting is clamped on a first portion of a surface on the frame that extends substantially at the acute angle, a periphery of the first portion of the surface of the frame under the primary spring being radiused to transition to a second portion of the surface of the frame under the primary spring that extends substantially parallel to the plane orthogonal to the axial dimension; characterized in that said at least one secondary spring is in the form of a straight flat beam that extends from said first end to an intermediate portion near said second end where the flat beam is radiused in the direction of the frame.