Coal involves burning tons of minerals, concentrating the non-carbon elements of those minerals into coal ash and exhaust. A lot of those other minerals are radioactive or otherwise toxic.
However, to make a fair comparison you should also consider the toxic byproducts of uranium extraction and purification. Coal is not refined in anywhere near the same degree as reactor-grade uranium.
If you're going to consider those for uranium you also need to consider them for coal.
The energy density of uranium makes it a non-issue. A 1GW reactor fissions about 1 ton of enriched uranium per year. You need about 10x as much raw material, so we're talking about 10 tons of uranium per year.
If you can't reprocess, then you lose about 95% of the fissionable material in the uranium. So you use up 20 tons of material per year, and you need to mine about 200 tons.
In comparison, a 1GW coal plant uses about 3 million tons of coal per year. And be real, coal isn't particularly clean to mine either. You need to wash it, and that water ends up just as polluted with heavy metals as the fly ash. Not to mention the human toll - black lung disease still killed about 25k people in the year 2013, and incidence rates (in the active miner population) have actually been rising since the 1990s.
It's the difference between a small-scale mining operation and large-scale strip mining.
> However, to make a fair comparison you should also consider the toxic byproducts of uranium extraction and purification. Coal is not refined in anywhere near the same degree as reactor-grade uranium.
If I understand correctly, these waste products are liquid or solid that can be stored, rather than dispersed into the atmosphere like coal byproducts. (Of course, storage poses its own technical challenges, like warning people in fifty thousand years not to mess with them, and the Hanford site's current leakage problems.)
Fission by-products include irradiated water, radiactive xenon (a problem as that turns out to be a neutron-absorbant and resulted in unexplained power-loss on early nuclear reactors), and other gasses.
My understanding is that this is from the radioactive carbon-14 isotope which is in the CO2 emitted, at something like one part per trillion. So it should apply to any non-CCS powerplant.
But it's still misleading, since essentially all of that CO2 will remain in the atmosphere, while radioactivity in the form of uranium, plutonium etc. will all rain down to the ground quickly (i.e. "fallout").
Edit: I remembered wrong, carbon-14 isn't the problem. It's uranium etc. in the ash from coal powerplants. Disregard this post.
