Why can’t we dump nuclear waste in the same place we mine nuclear fuel?
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Old mining shafts are the most common places to store nuclear waste, so we kind of do that.
Its just that these shafts have to be checked and prepeared because if there is for example leaking water, it could radiate whole lakes and countries.
There are relatively reasonable methods to dispose of nuclear wastes, in fact quite a few of them. None of them really very new either.
The problem is not technology, it is political.
If someone takes a decidedly anti-nuclear position, they aren’t particularly interested in seeing practical solutions weakening their arguments. So it becomes an eternal round of demonstrating methods, only to be met with conspiracy theories and accusations of lies and demands of perfection beyond feasibility. And this is a tough battle that few governments were interested in confronting – so it simply becomes gridlock and eternal arguments.
As others have said you don’t find uranium ore in huge chunks and even those are not highly radioactive. Once the the highly concentrated/enriched uranium has been used in a reactor it becomes highly radioactive and cannot be simply put back into a mine or pit. That’s also just the uranium, a lot of the other parts of the reactor are now contaminated and must be stored properly.
Uranium ore is radioactive, but it is not quite the same amount of radiation. You need to refine and process in such a way that makes the material volatile enough to produce power. You can find uranium ore on the surface of a mountain if you know where to look and hiking around it is harmless.
Not all uranium is the same. Spent uranium fuel is “spent” because all the fissile uranium has decayed already. Fissile uranium is U^238 which means there are 92 protons and 146 neutrons in this isotope of uranium. This is the most common form of uranium [*in* Earth about 99.3%](https://www.radioactivity.eu.com/site/pages/Uranium_238_235.htm#:~:text=The%20half%2Dlife%20of%20uranium,and%20only%200.70%25%20uranium%20235). Enriching uranium gets you to a higher ratio of U-235 to U-238.
The fissile kind of uranium is U^235 which means 92 protons and 143 neutrons in the nucleus. [This isotope is fissile because when it is hit by a neutron the now U^236 fissions into barium-141 and krypton-92](https://chem.libretexts.org/Bookshelves/General_Chemistry/Map%3A_General_Chemistry_%28Petrucci_et_al.%29/25%3A_Nuclear_Chemistry/25.08%3A_Nuclear_Fission).
As the fissile uranium is used in fission less of U-235 exists in the fuel and eventually there’s a point of diminishing returns and at this point most of the fuel is U-238. So at this point the spent material no longer has sufficient U-235 to be useful for fission and is instead used in [military applications as armor piercing rounds, tank armor](https://www.epa.gov/radtown/depleted-uranium).
Because nuclear waste is not the same as nuclear fuel. Once the stuff is mined, it first must go through a long process where it’s concentrated and all the unwanted parts are stripped out.
Next, a portion is consumed in a nuclear reaction. A nuclear reaction physically changes one element to another. (Think gold into lead.) In this case, the reaction changes a radioactive material to a different element that’s a really REALLY radioactive material that can kill you if you just happen to walk past it unshielded.
Also, nuclear waste is not just the spent fuel. Everything that came into contact with the substance is now some level of nuclear waste. All the water used in a reactor, the clothes of the workers, any brooms used to sweep up, tools used in maintenance, even the nuclear plant itself will eventually become nuclear waste and need to be stored indefinitely.
Nuclear engineer here.
When you split atoms, the leftovers are different and extremely more radioactive than uranium.
Uranium from the ground is a very weak radiation emitter. Its only a problem if you eat it. The alpha radiation from uranium can’t penetrate a piece of paper.
Split atoms (fission products) are extremely radioactive. Millions of times more radioactive and can penetrate up to a foot of lead. So putting THAT in the ground is bad.
If we developed the technology, we could separate the unused uranium and put that back in the ground or remix it into new fuel. But the 7% of the nuclear fuel that is waste products needs to be stored still.
Because the countries who mine nuclear fuel don’t want it back? Plus most of the waste isn’t the fuel (which almost all recycled, even depleted uranium is used for artillery shells & armour), it’s other things that are contaminated like fuel rod casings, reactor shielding, pipes etc..etc..
If you’re interested in nuclear storage technology Kyle hill has a good video on how using drilling inspired from fracking is used for just that [https://youtu.be/4aUODXeAM-k](https://youtu.be/4aUODXeAM-k)
One basic issue is that nuclear power plants aren’t next door to uranium mines. After paying to ship the rocks to the plant, now you have to pay to ship the rocks back.
This is a massive outlay in money and fossil fuel emissions just to get the uranium there. Paying about the same to get it back would make nuclear power completely unfeasible even with its massive subsidies. Nuclear power already uses too much fossil fuel to be a real alternative to fossil fuel, shipping the rods back would make a coal power plant seem positively green by comparison.
If a corporation remembers to check the seals on the storage barrels, and the concrete tank’s lack of leaks, on a regular basis, storing the barrels at the plant under 30′ of water is actually a pretty good place. Trusting them to do this is another matter.
Water is amazing at blocking radiation, so much so that were you to *swim* in such a pool, about 1 inch below the surface, you would experience *less overall radiation exposure than at the surface.* This is because the 1 inch of water is blocking the natural background radiation of the Earth’s surface.
Don’t go 6′ down though, water is great at blocking radiation but the spent fuel rods are producing **way** more radiation than the Earth’s surface background radiation.
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