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Originally Posted by Xenophon
As cast, they're minimally radioactive, and stable over quite long time-scales.
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Don't you mean they emit a minimum amount of radiation relative to the SAME AMOUNT of radioactivity? A curie of cobalt 60 or strontium 90 will emit the same number of gamma rays whether it's diluted in fifty liters of lead glass or not. The difference is the flux density at the surface. And stability is only in terms of chemical stability. Radioactive material is by definition unstable and all the dilution in the world will not make it less so.
Quote:
Originally Posted by Xenophon
The resulting billets are stable for 20,000+ years. (Really! The French nuclear agency did some super-careful research on ancient Egyptian glass that's over 5K years old in order to learn about the long-term stability of glass. From there, it's cube-square-law on the dimensions with leaching rates and such as measured. Very solid data!)
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Quote:
Originally Posted by Xenophon
The secure dry storage is overkill even for the small billets, but it makes the public feel safer, so that's what they do. Note that maintaining that dry storage, and providing security for it(!) is a major fraction of their reprocessing cost -- the original big-billet plan would be much cheaper.
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In terms of life spans of civilizations, 20K years is a long time! Long enough to see several civilizations come and go. Would you have us believe that, say, middle age Europe would expend the resources to maintain dry storage and provide security for Egyptian glass?