[2F01-04] Waste Disposal from the Fukushima Daiichi Accident

[2F02] Basic Studies for Developing Rational Treatment and Disposal System of Radioactive Wastes Generated by Fukushima Dai-ichi Nuclear Accident

(56) Precipitation of Calcium Carbonate in Compacted Bentonite by Electrokinetic Method

＊Jaka Rachmadetin¹, Masaya Mizuto³, Shingo Tanaka², Naoko Watanabe², Tamotsu Kozaki² (1.Graduate School of Engineering Hokkaido University, 2.Faculty of Engineering Hokkaido University, 3.Tokyo Nuclear Services Co., Ltd.)

Keywords:Radioactive waste disposal, Compacted bentonite, Calcium carbonate, Electromigration

Calcium carbonate precipitation may occur in bentonite which will be used as an engineered barrier in disposal of radioactive waste generated from Fukushima nuclear accident. In this study, an electrokinetic method was used to enhance the calcium and carbonate migration in saturated sodium bentonite. Sequential extraction method was developed to quantify different states of cations and anions in compacted bentonite after the electromigration experiment. The conditions for CaCO₃ precipitation are discussed based on the spatial distribution and chemical states of ions both in the interlayer and in the pore water of bentonite.