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Comment by supert56 | Hacker News Reader

My only question about nuclear is why is it okay to bury the nuclear waste?

I can understand that it might be fine to bury small amounts in specific stores but if countries slowly adopt nuclear energy at scale then over time won’t we be burying a lot of waste that, correct me if I’m wrong, has to be stored for thousands of years? I don’t understand how this can be sustainable long term. I also think it’s maybe arrogant of us to assume that it will always be safe to just store it and that something won’t happen that could disrupt that.

I’m no expert on this though so if someone has a great explanation I’d love to understand it.

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https://en.wikipedia.org/wiki/Onkalo_spent_nuclear_fuel_repo...

Is a good starting point. There has been a lot of thought put into this.

I think it becomes palatable when compared to the alternative. Coal power puts out nuclear material into the air. I would rather see it buried in the stable locations picked so far.

Think about it this way.

All of the uranium used as fuel came from the ground. Now, we will be putting smaller quantity of other, also radioactive, materials into ground. Lot of places have high natural levels of radiation[0], sometimes they even make it as a spa location[1].

People were living around radiation since before they were people. And they managed. We still do.

In the end the question is if we want some radioactive pollution that is easy to contain in the near term, or a lot more carbon pollution that is impossible to contain in the near term.

One is destroying the planet as we speak. The other might be a problem few centuries in the future, if there is one.

[0]https://en.wikipedia.org/wiki/Background_radiation#Areas_wit...

[1]https://en.wikipedia.org/wiki/J%C3%A1chymov#Spa

It's really not that simple. Enriching the raw materials and subjecting them to fission results in a waste product with quite different characteristics than the input.

I know nothing about nuclear physics; could you elaborate? How are the input and output different?

You can hold natural uranium in your hand for a long time before it becomes a health concern. It's toxicity (heavy metal!) is more dangerous than its radioactivity. You shouldn't try the same with spent fuel or you will lose you arm quickly.

Uranium 235 can decay by splitting into two smaller nuclei and releasing some free neutrons. Frequently those smaller nuclei are themselves radioactive. Uranium has a very long half life, on the order of billions of years, so the natural rate of decay is very low. This makes it relatively safe, since there is not too much radiation produced per second. Many of the product nuclei that can be formed have a much shorter half life. So they emit more radiation, though on the plus side they don't last as long. In nature, these smaller nuclei are still formed, but at a very low rate. In a nuclear reactor, the uranium is bombarded with a large number of neutrons, and it has a chance of splitting whenever a neutron hits it. So there's a high rate of decay, and as a result, once the fuel has been in the reactor for a while, it contains a large amount of those fission products. That's what makes the waste more dangerous: it has isotopes in it that decay faster and therefore emit more radiation per second than pure uranium.

This is a really helpful explanation. I didn't have a clue that the long half life actually results in lower levels of radiation.

Thanks to everyone for your replies below, they provided me with some really useful insights and I understand that it's definitely less directly polluting than fossil fuels and that it's also part of an interim plan.

However. I still think humanity can do better.

If we put all the energy, resources and research that we are putting into nuclear into truly sustainable energy like wind, solar, wave and geothermal, which to my knowledge produce less or no byproducts, then that would be best.

It's unfortunate that the world can't take an aligned approach and build solar farms in deserts, wind farms at sea, wave energy on coastlines and then just export it all fairly to countries. I think I'm almost campaigning for energy as a global right and not for sale as a commodity.

It is not risk free, but it is "okay"

Most of newer reactor design produce very little waste -- the newest type of reactor produce only a few pounds of spent fuel a year per 1GW.

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