| 摘要 |
<p>1,063,631. Fuel elements. UNITED KING- DOM ATOMIC ENERGY AUTHORITY. Jan. 21, 1965 [Feb. 6, 1964], No. 5172/64. Heading G6C. A fuel element, comprising a uranium or uranium base alloy in a sheath of a magnesium base alloy also containing zirconium, has a substance diffused through at least part of the sheath wall thickness which prevents diffusion of plutonium through the sheath by forming an intermetallic compound with the plutonium. The substance is preferably aluminium, although it may alternatively be aluminium-silicon, copper, nickel, or copper and nickel based alloys. The substance is preferably applied initially to the fuel body in the form of a wrapping of foil, although it can be applied to the sheath interior, and may in both cases be applied alternatively by vacuum deposition, electro deposition, spraying or dipping. The fuel and sheath are assembled with a layer of the substance between them, and heat and pressure applied. In the case of aluminium, it forms an intermetallic compound with the sheath zirconium, and consequently sufficient aluminium must be used to ensure that an uncompounded layer has diffused into the can which will combine with the plutonium as it is formed during fission of the fuel element. The diffusion is not necessarily completed during manufacture ; it may continue to take place from the remaining layer between the fuel and sheath during use in the reactor.</p> |
