Acquisition of saltwater infiltration behavior data in unsaturated compacted bentonite

Sato, Hisashi*; Takayama, Yusuke; Suzuki, Hideaki*; Sato, Daisuke*

JAEA-Data/Code 2023-010, 47 Pages, 2023/09

JAEA-Data-Code-2023-010.pdf:1.45MB

When a high-level radioactive waste repository is constructed in a coastal area, it is necessary to fully evaluate the impact of seawater-based groundwater on engineered barriers, including buffer materials. In this report, one-dimensional saltwater infiltration tests were conducted to obtain data to understand the impact of seawater-based groundwater on the migration phenomena of water and solutes in the buffer material during the transient period. As a result, it was confirmed that the infiltration rate increased as the NaCl concentration in the infiltration solution increased. And it was confirmed that the water content ratio distribution changed as the NaCl concentration in the infiltration solution increased. As a result of analysis of the chloride ion concentration of the post-test specimens confirmed that chloride ion enrichment was occurred with infiltration. As a result of verifying the mechanism by which chloride ion enrichment occurs, it was confirmed that the phenomenon of chloride ion enrichment due to infiltration depends on the initial water content ratio.

Effects of water radiolysis on the corrosive environments of overpack at the transition period

Sato, Tomonori; Hata, Kuniki; Igarashi, Takahiro; Otani, Kyohei; Kato, Chiaki

no journal, , 

It is estimated that the outer surface of the overpack of high-level radioactive waste during the transition period of the geological disposal is exposed to the groundwater percolated into the bentonite under irradiation. So, evaluations of water radiolysis considering the contribution of bentonite is one of the important factors to understand the corrosive environment. In this study, the results of the contribution of impurities leaching from bentonite and coexistence of bentonite in the water radiolysis are reported.