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Solar modules deployed in France in 1992 still provide 75.9% of original output power
(www.pv-magazine.com)
This is a most excellent place for technology news and articles.
I'm speaking strictly of the mass. Most the volume on those containers are likely structure to make sure there is no accidental leak, similar to Switzerland.
I also misremembered, it was all of US' waste that could fit on a single football.
Unfortunately, there's not much structure to these, no. It's nuclear waste from the 60s and early 70s, when there were practically no safety laws in place yet. They just got dumped down there in steel barrels. In a salt mine, which now has water entering it. I'm hoping, the barrels got at least filled up with concrete, but I have no idea.