Water-Rock Interaction of Granite From Borehole BS34 at Different Temperatures

Abstract

In the process of deep geological disposal of high-level radioactive waste, the decay of nuclide will generate a large amount of heat, which is released into the surrounding environment and affects the water-rock interaction of the deep geological environment. In order to explore the impact of temperature on the chemical environment of the deep groundwater in the Xinchang site, the undisturbed groundwater and deep granite samples at the Xinchang site were used to carry out water-rock interaction study at different temperatures. The research results show that the granite sample from borehole BS34 reacts with the undisturbed groundwater. The final pH value of the aqueous phase is between 6.4-8.5, and the TDS is between 1 653.9-1 759.6 mg/L. With the increase in temperature of the reaction system, the concentrations of Na+ and K+ in the aqueous phase increase, resulting from the dissolution of albite and cation exchange for Na+, and the dissolution of K-feldspar for K+, respectively. Meanwhile, the concentrations of Ca2+, Mg2+ and HCO-3 decrease, mainly due to the precipitation of calcite and dolomite. The higher the reaction temperature, the more calcite and dolomite are precipitated.

Keywords

• water-rock interaction
• different temperature
• hydrochemical characteristics
• high-level radioactive waste disposal
• undisturbed groundwater