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

2000 Fiscal Year Final Research Report Summary

• Project/Area Number: 11480127
• Research Category: Grant-in-Aid for Scientific Research (B).
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Nuclear engineering
• Research Institution: KYUSHU UNIVERSITY
• Principal Investigator: SUGISAKI Masayasu Kyushu Univ., Interdisciplinary Graduate School of Engineering Sciences. Prof., 大学院・総合理工学研究院, 教授 (10037905)
• Co-Investigator(Kenkyū-buntansha): SAKAMOTO Kan Kyushu Univ., Interdisciplinary Graduate School of Engineering Sciences. Research Associate, 大学院・総合理工学研究院, 助手 (50301346)
• Project Period (FY): 1999 – 2000
• Keywords: Zircaloy / Tritium / Microautoradiography / High Burn-up / Hydrogen embrittlement

Research Abstract

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.