nuclear-news

Vitrified nuclear waste: glass corrodes and melts long before the radioactive trash is inert

What causes nuclear waste glass to dissolve? Phys Org,   University of Houston  October 10th, 2018  

Immobilizing nuclear waste in glass logs—a process known as vitrification—is currently used in the United States to safeguard waste from sites associated with defense activities. Some other countries also use the process to capture waste from nuclear power plants.

Researchers know, however, that the glass can begin to dissolve after a long period of time, and the durability of these glass logs remains an active area of research.

Researchers from the University of Houston, the Department of Energy’s Pacific Northwest National Laboratory and the University of Pittsburgh are working on one of the most pressing issues—what causes the glass to begin to deteriorate relatively quickly at some point, potentially releasing radioactive waste at levels exceeding regulatory thresholds?……….”We have long observed from laboratory studies that zeolite formation in glass corrosion tests resulted in an increase in the glass corrosion rate,” said Neeway, a researcher at PNNL.   ………
Zeolite P, the zeolite that forms from the glass, is affected by temperature—Rimer said researchers synthesize it in the lab at 100 °C—but they don’t yet know how crystallization proceeds at lower temperatures and they don’t have methods to deter its formation. But controlling temperatures in the geologic formations designated as nuclear waste repositories is not necessarily practical, thus researchers are looking for other factors that might affect crystal growth, including components of the glass. https://phys.org/wire-news/300629772/what-causes-nuclear-waste-glass-to-dissolve.html

October 11, 2018 - Posted by Christina Macpherson | Reference, safety, wastes