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Current model for storing nuclear waste is incomplete: Study finds the materials -- glass, ceramics and stainless steel -- interact to accelerate corrosion:

The materials the United States and other countries plan to use to store high-level nuclear waste will likely degrade faster than anyone previously knew because of the way those materials interact, new research shows.

The findings, published today 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 Center 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 defense waste, the legacy of past nuclear arms production. The waste is highly radioactive. While some types of the waste have half-lives of about 30 years, others — for example, plutonium — have a half-life that can be tens of thousands of years. The half-life of a radioactive element is the time needed for half of the material to decay.

The United States currently has no disposal site for that waste; according to the U.S. General Accountability Office, it is typically stored near the plants where it is produced. A permanent site has been proposed for Yucca Mountain in Nevada, though plans have stalled. Countries around the world 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 defense 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 -- now radioactive -- inside metallic canisters. The canisters then would be buried deep underground in a repository to isolate it.

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.

The study qualitatively measured the difference between accelerated corrosion and natural corrosion of the storage materials. Guo called it "severe."

Journal Reference:

Xiaolei Guo, Stephane Gin, Penghui Lei, Tiankai Yao, Hongshen Liu, Daniel K. Schreiber, Dien Ngo, Gopal Viswanathan, Tianshu Li, Seong H. Kim, John D. Vienna, Joseph V. Ryan, Jincheng Du, Jie Lian, Gerald S. Frankel. Self-accelerated corrosion of nuclear waste forms at material interfaces. Nature Materials, 2020; DOI: 10.1038/s41563-019-0579-x

Original Submission