Transit flask for radioactive objects

1,103,787. Shielded containers for radioactive material. COMMISSARIAT A L'ENERGIE ATOMIQUE. 5 May, 1966 [21 May, 1965], No. 19862/66. Heading B4Q. A flask for transporting an irradiated fuel element to a hot cell and having means whereby it may be sealed to an aperture in a vertical wall of the cell (Fig. 4, not shown) to permit transfer of the element through the aperture, comprises a lead-filled casing 10 provided with a removable dome 14. The flask is used horizontally with a shielding plug 30 facing upwards so that when the dome 14 is removed a frusto-conical nose 12 may be engaged with a similar-shaped surface surrounding the aperture in the hot cell wall. A stepped passageway 18 on the axis of the casing 10 normally sealed at the rear end by a plug 26 receives a tube 34 containing a cradle (36) (Fig. 2, not shown), the cradle carrying the fuel element. The front end of the passageway 18 is sealed by a screwthreaded plug 22 and by a plug 24, the latter plug being removed at the same time as the dome 14. The front ends of the tube 34 and cradle (36) are normally locked together by interengaging lugs (44, 48) and may be disengaged by relative rotation through 30 degrees. In use, after mating of the nose 12 with the hot cell aperture, the plug 26 is removed and a push-rod (52) (Fig. 3, not shown) is coupled to the rear end of the tube 34. The plug 30 is removed and the plug 22 raised by a screwing motion whereupon the tube 34 is advanced by the rod (52) until the front end of the cradle (36) constituted by a stopper (38) engages a stopper (381) locked by interengaging lugs (441, 481) in an opening formed in a collar (68) defining an entry in a liner (66) of the hot cell (Fig. 4, not shown). The tube 34 is rotated through 30 degrees by the rod (52) to lock together the stoppers (38, 381) by interengaging lugs (74, 741) and also to lock the tube 34 with the collar (68) by interengaging lugs (42, 421). A manipulator (not shown) in the hot cell now rotates the stoppers (38, 381) as a unit to disengage the lugs (48, 481) and permit withdrawal of the stoppers together with the cradle (36) into the hot cell.