| 摘要 |
<p>The nuclear fuel rod comprises fuel pellets enclosed in a cladding which has an inner layer of Zircaloy 4 and an outer layer of a zirconium-based alloy. The outer layer contains, apart from zirconium and unavoidable impurities: - from 0.35 to 0.65 % by weight of tin, - from 0.18 to 0.25 % of iron, - from 0.07 to 0.13 % of chromium, and - from 0.19 to 0.23 % by weight of oxygen, the sum of the contents of iron, chromium and tin being lower than 1.03 %. In an alternative form the outer layer contains 0.8 to 1.20 % by weight of niobium, the oxygen content being then between 0.10 and 0.16 % by weight. The thickness of the outer layer is between 10 and 25 % of the total thickness of the cladding.</p> |
