Quantitative characterization of steel corrosion products and bentonite alteration in a 21-year experiment

21年間の炭素鋼ーベントナイト接触試験における鉄腐食生成物とベントナイト変質の定量評価

石渡 翔丸*; 菊池 亮佑*; 川喜田 竜平  ; 安楽 総太郎 ; 三ツ井 誠一郎 

Ishiwata, Tobimaru*; Kikuchi, Ryosuke*; Kawakita, Ryohei; Anraku, Sohtaro; Mitsui, Seiichiro

The engineered barrier system (EBS) in the geological disposal of high-level radioactive waste includes the iron- or steel-based overpack and a compacted bentonite buffer. Over long timescales, interactions between iron and bentonite may alter the barrier's performance. To ensure the long-term stability of the EBS, it is essential to quantitatively evaluate these interactions, providing fundamental data for predictive modelling. In this study, we performed a quantitative micro-scale analysis of mineralogical alterations and their spatial distributions across the steel-bentonite interface after 21 years of contact under controlled conditions, thereby providing a reliable basis for validating the observed alterations and supporting predictive modelling.