That's how much nuclear waste is hanging around the U.S. — a good bit of it in Illinois — with no feasible solution in sight that would provide long-term (or even middle-term), safe storage. The waste is comprised of spent fuel from nuclear reactors. As this report by Brian Wingfield explains:
With no place to send their waste, power plants in 30 states — which
generate about 20 percent of the nation’s electricity — are doubling as
dumps for spent fuel that remains dangerous for thousands of years.
Another four states without operating reactors store spent fuel at
closed plants. It is an expensive and, according to some critics, unsafe
practice for which the plants weren’t designed and that may end up
costing taxpayers billions of dollars.
It's not a good situation. Read the whole story.