A tube grid cell for a grid assembly including a plurality of tube grid cells and intended to hold a plurality of elongated fuel rods in a fuel bundle in a nuclear reactor, the tube grid cell is cylinder-shaped, has an essentially circular cross-section and an elongated extension along a longitudinal axis A, and has a length L, and that axis A has an essentially vertical direction during normal use; - the tube grid cell comprises a cell housing comprising a tubular housing wall defining a top opening and a bottom opening configured to receive a fuel rod, - the cell housing comprises, along the longitudinal axis A, a lower section, an upper section and a middle section placed between the upper and lower sections; - the middle section is provided with two pairs of support members each having a radially inward directed extension, one of said pairs is arranged close to an upper part of the middle section, and the other of said pairs is arranged close to a lower part of the middle section, the support members of each pair are arranged at a same plane being perpendicular to axis A and are positioned approximately 120 degrees apart seen along axis A, and the support members of one pair are arranged above the support members of the other pair, the middle section is further provided with a resilient member configured to generate a resilient force in an inward radial direction, the resilient member is arranged between said planes of the pairs of support members and at essentially equal distance from the planes of the support members, and positioned approximately 120 degrees apart from the support members seen along axis A, and characterized in that the upper section and the lower section have respectively a length L1 and L2 along axis A that is larger than 0.1L and smaller than 0.3L, i.e. 0.1L < L1 < 0.3L, and is provided with a solid housing wall, having an even thickness and no openings, indentations or protrusions, except for optional welding members extending from the housing wall along axis A, wherein the solid housing walls of the upper and lower sections are structured to improve lateral properties of the grid assembly which is made up of a plurality of tube grid cells welded together, and wherein the upper and lower sections are structured such that the welding can be performed at the upper and lower sections, e.g. by laser welding. - the tube grid cell comprises a cell housing comprising a tubular housing wall defining a top opening and a bottom opening configured to receive a fuel rod, - the cell housing comprises, along the longitudinal axis A, a lower section, an upper section and a middle section placed between the upper and lower sections; - the middle section is provided with two pairs of support members each having a radially inward directed extension, one of said pairs is arranged close to an upper part of the middle section, and the other of said pairs is arranged close to a lower part of the middle section, the support members of each pair are arranged at a same plane being perpendicular to axis A and are positioned approximately 120 degrees apart seen along axis A, and the support members of one pair are arranged above the support members of the other pair, the middle section is further provided with a resilient member configured to generate a resilient force in an inward radial direction, the resilient member is arranged between said planes of the pairs of support members and at essentially equal distance from the planes of the support members, and positioned approximately 120 degrees apart from the support members seen along axis A, and characterized in that the upper section and the lower section have respectively a length L1 and L2 along axis A that is larger than 0.1L and smaller than 0.3L, i.e. 0.1L < L1 < 0.3L, and is provided with a solid housing wall, having an even thickness and no openings, indentations or protrusions, except for optional welding members extending from the housing wall along axis A, wherein the solid housing walls of the upper and lower sections are structured to improve lateral properties of the grid assembly which is made up of a plurality of tube grid cells welded together, and wherein the upper and lower sections are structured such that the welding can be performed at the upper and lower sections, e.g. by laser welding.