Thermal effect on long-term shale behavior in nuclear waste storage

R. Y. Makhnenko, H. Kim, K. Kim

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Shale-like formations can serve as barriers for geologic disposal of high-level nuclear waste. Adopting these tight materials has an advantage that any radionuclides emitted from the canisters would stay with hardly mobile pore water within the rock. However, there are a few issues associated with the sealing capacity of shales as high temperatures experienced in nuclear waste disposal can strongly affect their geomechanical and flow properties. In this study, we investigate how the continuous heating and hydromechanical loading are affecting the flow properties of a shale with the clay content above 50% and the dominant pore size on the order of tens of nanometers. Both intact and fractured specimens are considered, and parameters associated with a coupled hydromechanical model are measured in high-pressure laboratory experiments, including the time-dependent deformation introduced to the model through bulk viscosity. It appears that even a small increase in temperature from 24℃ to 40℃ significantly impacts long-term (viscoelastic) response of shale, while the effect on the short-term (poroelastic) behavior is less pronounced. At the same time, the thermal effect on the fluid flow is ambiguous: the permeability increases with temperature but is predicted to eventually decrease due to the accelerated rock compaction at elevated temperatures.

Original languageEnglish (US)
Title of host publication57th US Rock Mechanics/Geomechanics Symposium
PublisherAmerican Rock Mechanics Association (ARMA)
ISBN (Electronic)9780979497582
DOIs
StatePublished - 2023
Event57th US Rock Mechanics/Geomechanics Symposium - Atlanta, United States
Duration: Jun 25 2023Jun 28 2023

Publication series

Name57th US Rock Mechanics/Geomechanics Symposium

Conference

Conference57th US Rock Mechanics/Geomechanics Symposium
Country/TerritoryUnited States
CityAtlanta
Period6/25/236/28/23

ASJC Scopus subject areas

  • Geochemistry and Petrology
  • Geophysics

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