Procédé de fermeture étanche d'un élément combustible de pile atomique comprenant une gaine en matériau fritté

934,009. Nuclear fuel elements. COMMISSARIAT A L'ENERGIE ATOMIQUE. Oct. 9, 1961 [Oct. 18, 1960], No. 36171/61. Class 39 (4). A nuclear fuel element having a sheath 1 of fritted aluminium, magnesium or beryllium is sealed by a plug 3 of similar material, the sheath 1 with the plug 3 disposed inside one end being gripped in one jaw 5 of a welding machine, a counter-plug 4 being gripped in the other jaw 6, and the sheath 1, the plug 3 and the counter-plug 4 being flash-welded together. The exterior of the plug 3 and the interior of the sheath 1 are either both screw-threaded or both tapered and the plug 3 is accordingly either screwed or driven into the sheath 1 before welding. A considerable amount of degassing occurs on welding but, with the above arrangement, no gas is trapped within the sheath proper, only within the cavity 8 (Fig. 3), and this is released by cutting along the plane a-a. The material forming the bulge 7 is then machined away.