| 摘要 |
<p>972,466. Fuel elements. COMMISSARIAT A L'ENERGIE ATOMIQUE. Oct. 7,1963 [Oct. 26, 1962], No. 39507/63. Heading G6C. A nuclear fuel element comprising a tubular fuel rod clad internally and externally with metal sheaths connected by a thin annular plug enclosing the fuel, is characterized in that the inner surface of the plug has a larger area than the mean crosssectional area of the fuel rod. In Fig. 2 the tubular fuel 8a is clad with sheaths 10a 12a, of which the outer sheath 12a has a flared end. The plug 14a closes the ends of the sheaths and a spacing member 22 is interposed between the plug and the fuel rod. The member 22 may be of heat insulating material such as alumina, or may be of heat conducting material. A bearing ring 20a fits in a groove in the plug. The increased area of the plug improves its resistance to creep, and preferably one or both of its surfaces are roughened, as shown at 24, to prevent radial distortion and allow greater axial stresses. In an alternative construction, Fig. 3, the area of the plug 14b is increased by making it of frusto-conical form. In a further alternative, Fig. 4 (not shown), the outer sheath is flared, as in Fig. 2, and the plug is frusto-conical, as in Fig. 3.</p> |
