Abstract: The support is constituted by a spool comprising a base (F), and outer wall (1) having openings (4) therethrough, an inner wall (2) having openings (5) therethrough, and at least one cylinder (3). An outer ring (A) between the inner and outer walls serves to store slack lengths of fiber-carrier, and an inner ring (B) between said inner wall and said cylinder(s) serves to store slack lengths of optical fiber together with connection devices (11) for interconnecting the fibers. Lugs are provided on the inner and outer walls and on the cylinder(s) in order to hold the fiber-carriers and the fibers in place while the supports are being manipulated. The cylinders may be provided with rotatable covers, in which case the cylinder lugs are fixed to the covers.

Abstract: Tracer gases are contained in a capsule which is closed-off by a fusible seal and placed within the interior of each fuel-pin can. The capsule is formed of material having a melting point above the operating temperature of the fuel pins within a nuclear reactor. The fusible seal is formed of material having a melting point below said temperature, with the result that the tracer gases are released into the interior of each fuel pin at that temperature.