炭素鋼オーバーパックの性能保証に関わる腐食挙動評価ツールの現状

Status of Assessment Tools of Corrosion Behavior for Performance Guarantee on Overpacks

谷口 直樹 ; 川上 進; 神徳 敬; 油井 三和

Taniguchi, Naoki; Kawakami, Susumu; Jintoku, Takashi; Yui, Mikazu

国が策定するオーバーパックに関わる安全基準,指針等に資するため,これまでのオーバーパック腐食研究成果を基に,オーバーパック性能保証に関する評価ツールの検討を行った。ここでは,処分環境で考慮すべき腐食現象を挙げ,それぞれの現象に対する評価手法と評価例を現状の知見から整理した。処分環境において考慮すべき現象として,不動態化,全面腐食,局部腐食(孔食,すきま腐食,応力腐食割れ),水素脆化を挙げ,各現象の生起・進展挙動に関する実験的な評価方法を提示した。また,第2次取りまとめなどの研究成果を基に評価事例を示した。

In order to contribute to the safety standards and guidelines for overpacks on which the administration decides, the tools for performance guarantee on overpacks were studied based on the present research products for overpack corrosion. The corrosion modes that should to be considered in repository environments were extracted, and then the assessment methods and examples for each mode was summarized based on current understandings of corrosion behavior of overpacks.The passivation, general corrosion, localized corrosion (pitting corrosion, crevice corrosion, and stress corrosion cracking) and hydrogen embrittlement were extracted and the experimental methods to evaluate the initiation and propagation behavior were presented. The assessment examples based on research products such as second progress report (H12 report) were given.