In-situ Demonstration of Engineered Barrier System (In-Debs) at KURT: Coupled Thermal-Hydro-mechanical Behavior of Buffer

Demonstration tests of engineered barrier systems are essential to ensure the performance and safety of high-level radioactive waste repositories. An In-DEBS test was performed and the coupled thermal-hydro-mechanical (THM) behavior of the buffer was investigated. The In-DEBS test started operation on July 19, 2016, and has been successful so far. The THM behavior of the buffer was analyzed using the experimental data of the temperature, relative humidity, and total pressure. The distribution of temperature, relative humidity, and total pressure was observed with respect to time and sensor location. The temperature reached a steady state within a few days to several weeks after heating the heater. On the other hand, changes in relative humidity and total pressure over 1118 days were much lower than expected, which was thought to be because the amount of groundwater inflow from the rock mass around the test deposition borehole was local and limited. (C) 2021 Elsevier Ltd. All rights reserved.