3 ms·
> Vitrified nuclear waste, immersed, would become porous and friable long before its radioactivity decayed significantly. Not quite. Silicates form a passive g
by kergonath 4y ago
> Vitrified nuclear waste, immersed, would become porous and friable long before its radioactivity decayed significantly.
Not quite. Silicates form a passive gel layer when put in water, they are quite resistant to leaching (we have examples of ancient Egyptian glass items recovered from the sea). Over very long time frames, way longer than millennia, the glass just dissolves. But for this you’d need them to be immersed and constant water circulation; silica is very stable. In this case you’re not worried about radionuclides release too much anyway, as the seas tend to be very large and have already quite a bit of them. Plus, only the low-activity isotopes remain isotopes after that time.
- ncmncm 4y agoRadionuclide glasses should be expected to be less stable than ordinary silicates.
- kergonath 4y agoIt depends on what you call “ordinary silicates”. The matrix is mostly sodium borosilicate with a bunch of additives and is as stable as a glass could be. There are precipitates caused by some of the waste elements (things like ruthenium, rhodium and palladium, for example). They have issues but still quite far from making the glass crumble. As with all glasses, crystallisation is an open question but won’t happen for a very long time either.