Study of hydrogen permeation through oxide layer of zircaloy with tritium microautoradiography

用氚显微放射自显影技术研究了锆合金氧化层中氚的空间分布。锆合金（zircaloy-2）在723k的蒸汽中氧化。氧化后，在室温下用氚水阴极充电法在锆-2表面形成氧化层，通过氧化层引入氚。用扫描电子显微镜（SEM）观察了氧化膜的表面和截面的自射线照相。氢在内基合金的晶界和晶粒中有较密集的分布，而在氧化层中分布较少。然而，氢是局部分布的，在与嵌入氧化物层的金属间析出相对应的区域。

Spatial distribution of tritium in the oxide layer formed on zirconium alloy was examined by tritium microautoradiography. The zirconium alloy (zircaloy-2) was oxidized in steam at 723 K.After the oxidation, tritium was introduced through the oxide layer formed on zircaloy-2 by the cathodic charging method using tritium water at room temperature. The autoradiographs of the surface and cross-section of the formed oxide films were observed with a scanning electron microscope (SEM). Hydrogen was densely distributed on the grain boundary and in the grain of the inner base alloy, but it was scarcely distributed in the oxide layer. Hydrogen was locally distributed, however, in the region corresponding to the intermetallic precipitates embedded in the oxide layer.