Rock salt could be less effective than believed as a subsurface container for nuclear waste, according to new research from the University of Texas at Austin.
Salt beds are already used for safe storage of low-level nuclear waste at the Waste Isolation Pilot Plant in New Mexico, and have been discussed as a storage option should the stalled Yucca Mountain repository in Nevada go permanently moribund. They are also used for waste storage in Germany, according to a UT press release.
While salt in the ground has been considered as a “sealant” around nuclear waste in storage, as reported by The New York Times last year, UT researchers using field tests and laboratory-based 3-D micro-CT imaging determined that rock salt might be more porous than believed and less capable than figured of keeping nuclear waste from groundwater following potential failure of the storage container.
The problem might be “deformation” of rock salt, according to the press release: “Deformation can stretch the tiny isolated pockets of brine that form between salt crystals and link them into a connected pore network that allows fluid to move.”
“The critical takeaway is that salt can develop permeability, even in absence of mining activity,” assistant professor Marc Hesse of the Jackson School’s Department of Geological Sciences, said in the release. “Further work is necessary to study the quantity of flow that can occur.”
The research was published in the Nov. 27 issue of Science magazine.
