Clarification of Mechanism of Hydrogen Accelerated Oxidation and Development of Hydrogen Charging Technique in High Temperature and High Pressurized Water

本研究旨在阐明低碳奥氏体不锈钢在模拟沸水堆环境中的氢加速氧化（HAO）机理，发展高温高压水充氢技术。实验结果证实，在钢中充氢后，内层氧化膜中Cr浓度降低，空位浓度增加。此外，在模拟沸水堆环境中的小冲杆试验表明，充氢后的钢中观察到应力腐蚀开裂（SCC），并加速了裂纹尖端的氧化。这一结果表明，SCC的启动可能受到HAO的强烈影响。

The purpose of this study was the clarification of hydrogen accelerated oxidation (HAO) mechanism of low carbon austenitic stainless steel in simulated BWR environment and development of hydrogen charging technique in high temperature and high pressurized water. The experimental results have confirmed that by charging hydrogen into the steel, the Cr concentration decreases and the vacancy concentration increases in the inner layer oxide film. Additionally, the small punch test in the simulated BWR environment revealed that the stress corrosion cracking (SCC) was observed in the hydrogen charged steel and the oxidation of crack tip was accelerated. This result suggests that the initiation of SCC may be strongly influenced by the HAO.