[en] The invention proposes a nuclear fuel assembly spacer grid holding the rods with elasticity and efficiency, involving only a small pressure loss in the coolant, ensuring a good mixing of the fluid layers and representing a low quantity of neutron absorber materials. A spacer grating for a nuclear fuel assembly of an under-moderated reactor comprising parallel rods consists of a surrounding band encompassing the entire rod cluster and groups of parallel wires passing between adjacent rows of the rods to form a honeycomb through which they pass. The wires are arranged in layers, spaced axially along the rods and each layer comprises two groups of wires; in each group all the wires are parallel to one another and to one side of the surrounding band, so that with two such layers the groups of wires involved (usually four in number) provide wires in all the necessary directions, i.e. in three directions spaced at 120 deg in the case of a triangular fuel rod lattice