A storage rack for nuclear fuel assemblies, comprising a rigid structure defining a plurality of adjacent cells, and comprising in each cell a sleeve defining a cavity intended to receive a nuclear fuel assembly, the sleeve having, in cross-sectional orthogonal to the longitudinal direction, a generally polygonal shape whereof the sides are produced using plates made from a neutron-absorbing material. According to the invention, the sleeve also includes: profiles each forming a corner piece, arranged on at least several angles of the generally polygonal cross-section, these profiles serving as a mounting bracket for the plates made of a neutron-absorbing material; and a structure for maintaining the profiles therebetween.