Waste Management

Final Disposal / Repository Materials Could Degrade Faster Than Previously Thought, Says Research

By David Dalton
29 January 2020

Repository Materials Could Degrade Faster Than Previously Thought, Says Research
The US began work on a final repository at Yucca Mountain in Nevada, but the project was shelved.
The materials the US and other countries plan to use to store high-level radioactive waste will probably degrade faster than anyone previously knew because of the way those materials interact, new research shows.

The findings, published in the journal Nature Materials, show that corrosion of nuclear waste storage materials accelerates because of changes in the chemistry of the nuclear waste solution, and because of the way the materials interact with one another.

“This indicates that the current models may not be sufficient to keep this waste safely stored,” said Xiaolei Guo, lead author of the study and deputy director of Ohio State’s Centre for Performance and Design of Nuclear Waste Forms and Containers, part of the university’s College of Engineering. “And it shows that we need to develop a new model for storing nuclear waste.”

The team’s research focused on storage materials for high-level nuclear waste — primarily defence waste, the legacy of past nuclear arms production. It suggests that corrosion could be significantly accelerated at the interfaces of different barrier materials, which has not been considered in the current safety and performance assessment models in the US.

The US currently has no disposal site for that waste and it is typically stored near the plants where it is produced. A permanent site has been proposed at Yucca Mountain in Nevada, though plans have stalled. Other countries have debated the best way to deal with nuclear waste; only one, Finland, has started construction on a long-term repository for high-level nuclear waste.

But the long-term plan for high-level waste disposal and storage around the globe is largely the same. It involves mixing the nuclear waste with other materials to form glass or ceramics, and then encasing those pieces of glass or ceramics inside metallic canisters. The canisters then would be buried deep underground in a repository.

In this study, the researchers found that when exposed to an aqueous environment, glass and ceramics interact with stainless steel to accelerate corrosion, especially of the glass and ceramic materials holding nuclear waste.

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