[en] A can for introducing a fuel-rod into/an irradiation reactors in which comprises its own upper and lower polygonal plates as well as connecting members, axially aligned between said plates and radially resilient, each of which is provided with an inwardly directed radial protrusion, characterized in that said can is in the form of a cylinder with C-shaped cross-section, the concave surface of which is adapted to receive a fuel rod so that said rod can freely move both axially and radially along a portion of its periphery whereas the cylinder convex surface mates with the inner polygonal surfaces of at least one of the above polygonal plates, the can being provided with axial slots so arranged as to receive the above mentioned radial protrusions, whereby the sides of said slots clamp the niddle portions of the connecting members outwardly