The present invention discloses a stacker for a tray feeder including: a plurality of frames for forming an outer portion of the stacker; an elevator capable of moving upwardly and downwardly and positioned at a side of an auxiliary frame of the plurality of frames; a driving means for driving the elevator; and a magazine for receiving the tray plates and mounted to the elevator. The fuel rods include a plurality of short-length fuel rods each having a fuel active length shorter than that of each of remaining ones of the fuel rods. Production of said electromechanical component incurs drastically reduced costs compared to electromechanical components produced using silicon-based technology because simple injection-moulding andor embossing processes, instead of the complicated silicon-based technology, can be used for producing said electromechanical component. The louvered panel includes a plurality of adjustable parallel slats for obtaining an optimum deployment angle.