Retention mechanisms of selenium in deep subsurface sedimentary formations in Horonobe area, Hokkaido, Japan

Dei, Shuntaro  ; Tachi, Yukio  ; Amano, Yuki   ; Sugiura, Yuki  ; Francisco, P. C. M.  ; Takahashi, Yoshio*

Se is one of the key radionuclides for safety assessment of the high-level radioactive waste (HLW) due to its long half-life and complex speciation depending on the redox condition. Since selenium is considered to be easily migrates as an anion, it is important to understand the retention mechanism of Se in the subsurface environment. The aim of this study is to elucidate the retention mechanisms of Se in the deep subsurface by clarifying the speciation of Se.