Hacker News new | past | comments | ask | show | jobs | submit login

It's mostly due to the chemistry required to liberate the Uranium from the ore. What you have in the ore is mostly Uranium oxides. You have to strip away those pesky oxygen atoms in order to further process the Uranium. And in that process quite the amount of CO2 is produced. Now keep in mind that this must be done to all the Uranium, before it undergoes enrichtment. So for every atom of U235 you get about 200 (give or take) atoms of U238 and you have to account for all of them on the chemical side of things.

It's not that much better with Throrium either.

Throrium is produced anyway as a waste product. No additional mining is needed.

What part of that process produces CO2? I'm reading up on it but everything I find gives a fairly simplified view of things. The chemical reactions discussed on Wikipedia (https://en.wikipedia.org/wiki/Uranium_hexafluoride) don't involve any carbon, but maybe it's from some secondary aspect?

How is that compared to mining for battery and solar material? It's a double standard to hold nuclear accountable for manufacturing when the same is not applied to solar/wind.

I didn't compare it to battery/solar at all. I just wanted to point out one source for the chemical environmental impact of Uranium refinement.

Alas, if we really compare to solar, then keep in mind that for a solar cell you can use 100% of the refined silicon, whereas with uranium you end up throwing away a large fraction (over 95%) with low enriched fuel, and an even larger fraction (over 99%) with high enriched fuel.

Add to that that uranium is not among the most abundant elements on Earth (about 1ppm), whereas silicon is the second most abundant element in the Earth's crust (about 27%). That alone gives silicon a huge advantage in energy/chemical impact on the environment compared to uranium.

Oh, and maybe I should point out that the chemistry to work with uranium is also a lot more nastier than with silicon. Uranium is a heavy metal, so it all happens through complexes and acidic chemistry, which limits the options on chemical pathways. Silicon OTOH is very similar to carbon in its chemistry, so there are vastly more options to process silicon, and that alone allows for far more efficient processes.

batteries and solar components need numerous extracts of minerals and a bunch of chemistry as well but as.you pointed out the solar lobby is happy to ignore all that when claiming they are a clean source of energy.

No source of energy is clean, in that respect. The best you can do is separate one time production and continuing operating pollution, and account for both. Using that to show pollution per Mhh at 5, 10 and 20 year intervals should be sufficient.

Reiterating my original comment, it would also be good to distinguish between the whole-lifecycle pollution generated now, with current electrical and transportation infrastructure, and the whole-lifecycle pollution you could achieve if you applied the "clean" technology to the whole lifecycle.

For example, solar panel production requires a lot of electricity. That electricity is mostly generated from fossil fuels. But if you supplied that electricity with solar panels instead, it would be way cleaner. Which is correct? We should probably present both numbers, if possible.

An optimistic upper bound (unlikely but possible renewable adoption for material production energy), and pessimistic lower bound (current mix of evnergy for material production), and a best guess. That might convey enough information to give someone a good guess as to how things might turn out.

It starts to sounds complicated, and to be a lot of information to digest for a decision, but another way of looking at it is that correctly assessing and planning for energy needs in the future is so important that ignoring information like that when making an assessment is irresponsible. We need more nytimes.com style widgets that allow you to tweak the values to easily digest data like this, and that clearly reference where the data and assumptions come from.

I agree that the full environmental cost should be known in all cases, but I hope you expect that the bias is somewhat justified by the fact that uranium functions as a fuel while solar and battery materials are multiple-use.

One can compare, but the nuclear industry pointedly ignores those areas, so I sort of assume it doesn't win on those points. Also solar/wind materials I would think are fairly recyclable.

The figures in TFA don't talk about solar, and the parent comments don't mention it. Who is making the supposed double-standard here?

Then you need to count the whole refining process that goes in making usable petrol, too. This is not totally unique to nuclear.

Of course you also need to count that. But accounting for extraction and refining adds something like 20% to fossil fuel emissions, whereas it's claimed to vastly increase total nuclear emissions.

Sure, but this is a percents vs quantities problem. If nuclear has almost zero emissions in power production even the smallest increase will look like a massive increase percentage wise. It still may compare very favorably to fossil fuels for lifecycle emissions.

The original comment linked to https://www.stormsmith.nl/i05.html which claims that, when you account for the full lifecycle, CO2 emissions from nuclear are comparable to CO2 emissions from coal. If true, then no, it's not a percents vs quantities problem, it's just a quantities problem.

> So for every atom of U235 you get about 200 (give or take) atoms of U238

How is that even a problem? Nuclear power plants do not require much fissionable material at all. Compare that with any fossil fueled power plant.

It means that you have to invest a lot of energy in extracting material that's thrown away later without going to extract one bit of energy at all.

For making solar cells you don't have to be picky in which isotope you make them from.

Also there's only about 1ppm of uranium in the Earth's crust, whereas silicon is the second most abundant material (27%). So you don't even have to spend a that much energy just to separate the non-silicon stuff from the silicon-stuff, whereas a huge amount of energy in uranium production is preoccupied with doing just that.

If you go outside and take any rock, you're holding in your hands mostly silicon and oxygen. Strip away the oxygen and you get pure silicon.

Thanks for the info. It's seeming that solar and wind are better from a full-lifecycle perspective, and if we can just solve that pesky energy storage issue then it's done.

Nuclear is oddly politicized, both pro- and anti-, whereas I think the truth is somewhere in the middle. It's not the worst power source but it's also not the best. It's not worth continuing to invest in for the future because better sources are already coming online that don't have the associated fallout risk, hazardous materials disposal issue, and intensive mining/refining processes.

Applications are open for YC Winter 2020

Guidelines | FAQ | Support | API | Security | Lists | Bookmarklet | Legal | Apply to YC | Contact