[en] A rack is provided for storage of fuel assemblies in water-filled pools, particularly for use in seismically active areas. The rack is formed of four independent grid structures, each restrained on only its two adjacent walls in a manner that will limit forces perpendicular to but not parallel to the wall. The interaction between two adjacent walls permits the absorption of forces in all directions. The grid structures are slidably supported between the adjacent grids so that all expansion forces are taken at central slidable supports