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Impact of Coupled Gas Migration Phenomena on Barriers for Highly Pollutant Wastes
Abstract
The present investigation deals with the thermal-hydro-mechanical behavior of barrier materials intended for the isolation of high-level nuclear waste (HLW). The study encompasses clayed soils typically considered for the engineered barriers (e.g. compacted bentonite, clay pellets and mixtures of MX80 bentonite powder with clay pellets) and it also investigates the interaction between the clay barrier and the surrounding rocks (i.e. the natural barrier). There have been several national and international efforts focus on the design of repositories for HLW and excellent progress has been made in this area. However, there are still some aspects that require further research, for example, gas migration phenomena through both clay barriers and interfaces between dissimilar materials typically present in the repository for HLW. An essential component of this research is a state-of-the-art multipurpose cell, developed in collaboration with Polytechnic University of Catalonia (UPC Barcelona). The experimental setup allows replicating on a scaled barrier’s prototype realistic conditions anticipated in geological repositories. Thus, throughout this research, laboratory experiments under controlled conditions in the lab are conducted to elucidate the effect of different factors that play a critical role in this problem, such as, effects of gas production flow rate inside barrier’s prototype, effect of temperature, initial dry density, swelling pressure of bentonite pellets and their mixtures, re-sealing ability of the barrier’s material, homogeneity/heterogeneity of barrier materials, micro and macroscopic changes in barrier’s material during hydration, the effect of interface roughness on gas flow and breakthrough pressure. In parallel, 3D printed physical models of fractures will be used to gain a better understanding of the fracture properties that rules fluid flow through them.
Citation
Ali, Muhammad (2022). Impact of Coupled Gas Migration Phenomena on Barriers for Highly Pollutant Wastes. Doctoral dissertation, Texas A&M University. Available electronically from https : / /hdl .handle .net /1969 .1 /198532.