Evaluation of Water Suction for Compacted Bentonite Buffer Under Elevated Temperature Conditions

A compacted bentonite buffer is a major component of engineered barrier systems, which are designed for the disposal of high-level radioactive waste. In most countries, the target temperature required to maintain safe functioning is below 100 degrees C. If the target temperature of the compacted bentonite buffer can be increased above 100 degrees C, the disposal area can be dramatically reduced. To increase the target temperature of the buffer, it is necessary to investigate its properties at temperatures above 100 degrees C. Although some studies have investigated thermal-hydraulic properties above 100 degrees C, few have evaluated the water suction of compacted bentonite. This study addresses that knowledge gap by evaluating the water suction variation for compacted Korean bentonite in the 25-150 degrees C range, with initial saturations of 0 and 0.22 under constant saturation conditions. We found that water suction decreased by 5-20% for a temperature increase of 100-150 degrees C.