Nuclear Waste Disposal

Advancing knowledge of coupled subsurface processes to enhance long-term disposal solutions

Research in this program addresses the need for secure disposal of the high-level radioactive waste that has been, and will continue to be, produced from nuclear power generation (and weapons production) across the world. After making key contributions to the research and licensing activities for the proposed Yucca Mountain repository in Nevada, Berkeley Lab scientists are now leading research and technology development to enable long-term waste disposal in other host-rock environments, such as shale, salt rock, and crystalline rock, and alternative repository designs.

We focus on the complex coupled subsurface processes–thermal, hydrological, mechanical, and chemical (THMC)–that are triggered by perturbations from repository construction, engineered barrier emplacement, and waste disposal. Advanced methods for evaluating and predicting these coupled processes are tested against experiments conducted at multiple scales, from micro-scale imaging of clay swelling and clay rock damage in laboratory settings to large in situ experiments in subsurface field observatories. What we learn from these studies on coupled processes helps us evaluate the potential long-term impacts on repository site safety. For example, temperature rise from radioactive decay triggers an increase in pore pressure, mechanical deformations, and chemical reactions, possibly generating rock damage and mineralogical changes that can strongly affect radionuclide transport. Without the ability to predict the long-term consequences of these early-stage subsurface perturbations, it is difficult to assess whether natural and engineered barriers can provide safe disposal options over thousands to millions of years.

Supported through DOE’s Office of Nuclear Energy, most of our research centers on waste disposal needs in the U.S., however, we work with partners from around the world and are heavily engaged in international collaborations such as the DECOVALEX Project and the Mont Terri Partnership in Switzerland.

Recent science & program advances

  • Developed the first fully coupled THMC simulation methods to model the behavior of strongly perturbed engineered barrier systems and host rocks for radioactive waste disposal
  • Used insights from cryo-TEM on the pore structures in smectites to conduct the first chemically informed predictive model of radionuclide retention by clay rock barriers
  • Established the scientific basis for a higher-temperature repository option with maximum temperature up to 200 oC based on micro- to meso-scale lab testing and long-term predictions of bentonite mineral alterations; and finalizing a test plan with partners to demonstrate this option in a full-scale in situ experiment in Switzerland
  • Developed and tested new monitoring technologies in several prominent field experiments testing a variety of host rock options. Examples include novel crosswell electro-magnetic sensing to measure brine migration in a salt heater test at the Waste Isolation Pilot Plant (WIPP) in New Mexico, and real-time continuous seismic acquisition to monitor potential for radionuclide transport pathways generated by fault slip at the Mont Terri underground research lab
  • Tested a workflow for characterization of hydrologically active fractures in deep crystalline rock in Sweden based on new borehole logging and deformation tools combined with detailed hydro-mechanical core analysis
  • Coordinated international collaboration between DOE’s disposal research program and various international waste disposal research and implementation organizations in an example of bringing together collective capabilities to tackle challenges that are difficult to solve alone
  • Led the international DECOVALEX project, a unique international research collaboration for advancing the understanding and modeling of coupled THMC processes in geological systems

Relevant Projects


EESA benefits from rich partnerships with our collaborators and sponsors. See project & program links above for more information.

Publication Highlights

DECOVALEX-2015: an international collaboration for advancing the understanding and modeling of coupled thermo-hydro-mechanical-chemical (THMC) processes in geological systems. Environ Earth Sci, 2018

Coupled Processes Modeling in Rock Salt and Crushed Salt Including Halite Solubility Constraints: Application to Disposal of Heat-Generating Nuclear Waste. Transp Porous Med, 2018

Complexity of fault rupture and fluid leakage in shale: Insights from a controlled fault activation experiment. Journal of Geophysical Research: Solid Earth, 2020

Effects of bentonite heating on U(VI) adsorption. Applied Geochemistry, 2019

Fully Coupled Hydro-Thermal-Mechanical Modeling of Brine Migration in Salt for Heat-Generating Nuclear Waste. Computational Geosciences, 2020

On the relationship between water flux and hydraulic gradient for unsaturated and saturated clay. Journal of Hydrology, 2012

Modeling of Coupled Thermo-Hydro-Mechanical Processes with Links to Geochemistry Associated with Bentonite-Backfilled Repository Tunnels in Clay Formations. Rock Mechanics and Rock Engineering, 2014

Structural Implications of Interfacial Hydrogen Bonding in Hydrated Wyoming-Montmorillonite Clay. The Journal of Physical Chemistry, 2020

On the impact of temperatures up to 200 °C in clay repositories with bentonite engineer barrier systems: A study with coupled thermal, hydrological, chemical, and mechanical modeling. Engineering Geology, 2015

Coupled THMC models for bentonite in an argillite repository for nuclear waste: Illitization and its effect on swelling stress under high temperature. Engineering Geology, 2017

The hydration of bentonite buffer material revealed by modeling analysis of a long-term in situ test. Applied Clay Science, 2019

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