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> by every other country that is pursuing a nuclear waste management program. This claim is simply false. Many countries reprocess nuclear waste: https://en.w

by pdonis 3y ago

> by every other country that is pursuing a nuclear waste management program. This claim is simply false. Many countries reprocess nuclear waste: https://en.wikipedia.org/wiki/Nuclear_reprocessing#List_of_sites https://en.wikipedia.org/wiki/Nuclear_reprocessing#List_of_s...

acidburnNSA 3y ago
Countries that reprocess nuclear waste still need a deep geologic repository for the fission products and minor actinides due to process losses. Reprocessing reduces the number of repositories you need for a given fleet size, but you still need a repository.
- pdonis 3y ago
  > Countries that reprocess nuclear waste still need a deep geologic repository That's possible, but even if it's done, it's only necessary for hundreds of years (because the radioactive isotopes left over have much shorter half-lives), not 100,000 years. Big difference.
  - acidburnNSA 3y ago
    Radiotoxicity does indeed drop to ore levels in 300-500 years but even then there are a few problem actors. Partitioning and transmutation can help with these, probably. https://en.wikipedia.org/wiki/Long-lived_fission_product https://en.wikipedia.org/wiki/Long-lived_fission_product
    - pfdietz 3y ago
      I consider the elements containing those isotopes to be prime candidates for space disposal, not burial.
pfdietz 3y ago
That list includes the US, which hasn't had commercial reprocessing in many decades. The truth is that reprocessing is an economic loser at this point; even France admits it. Separated plutonium literally has negative value; you lose money trying to fabricate fuel elements from it instead of using freshly enriched natural uranium. France still does reprocessing because whatever is done with spent fuel is not that expensive compared to the cost of just building and operating nuclear reactors, so the boondoggle is not that big.
- pdonis 3y ago
  > reprocessing is an economic loser at this point Not on a time scale of 100 years or so, let alone the 100,000 years that are being imposed as a requirement on geologic storage. On that time scale recovering unburned fuel from reprocessing will be cheaper than mining and refining fuel. > France still does reprocessing because whatever is done with spent fuel is not that expensive Yes, particularly when you factor in that reprocessing gives you a source of additional fuel (most of the "spent" fuel removed from reactors is actually not spent, and reprocessing recovers it for future use) that, as noted above, is expected to be cheaper than mining it in the not too distant future. > the boondoggle It's not a boondoggle at all, it's a rational way of anticipating future nuclear fuel requirements, as above. It's certainly much more rational than requiring spent fuel to be stored for 100,000 years as if that was the only possible thing that could be done with it.
  - pfdietz 3y ago
    > Not on a time scale of 100 years or so AT THIS MOMENT it's an economic loser. If you need reprocessed fuel in 100 years, by the miracle of nonzero interest rates you save money by doing it closer to then instead of right now. The cost of storing the fuel until then is low enough that this works out. > It's not a boondoggle at all, it's a rational way of anticipating future nuclear fuel requirements, as above. No, it's a waste of money to do it right now.
    - pdonis 3y ago
      > it's a waste of money to do it right now If you're allowed to store the current waste in a facility that's only good for 100 years or so, then yes. But not if you're required to store any waste you don't reprocess for 100,000 years.
      - pfdietz 3y ago
        Where does that requirement come from, though? If society is going to collapse in 100 years, I suggest the money be better spent preparing for the consequences of that, not worrying about whether the documentation on dry casks will satisfy some licensing requirement.

by pdonis 3y ago

acidburnNSA 3y ago

Countries that reprocess nuclear waste still need a deep geologic repository for the fission products and minor actinides due to process losses. Reprocessing reduces the number of repositories you need for a given fleet size, but you still need a repository.

pdonis 3y ago
> Countries that reprocess nuclear waste still need a deep geologic repository That's possible, but even if it's done, it's only necessary for hundreds of years (because the radioactive isotopes left over have much shorter half-lives), not 100,000 years. Big difference.
- acidburnNSA 3y ago
  Radiotoxicity does indeed drop to ore levels in 300-500 years but even then there are a few problem actors. Partitioning and transmutation can help with these, probably. https://en.wikipedia.org/wiki/Long-lived_fission_product https://en.wikipedia.org/wiki/Long-lived_fission_product
  - pfdietz 3y ago
    I consider the elements containing those isotopes to be prime candidates for space disposal, not burial.

pfdietz 3y ago

That list includes the US, which hasn't had commercial reprocessing in many decades. The truth is that reprocessing is an economic loser at this point; even France admits it. Separated plutonium literally has negative value; you lose money trying to fabricate fuel elements from it instead of using freshly enriched natural uranium. France still does reprocessing because whatever is done with spent fuel is not that expensive compared to the cost of just building and operating nuclear reactors, so the boondoggle is not that big.

pdonis 3y ago
> reprocessing is an economic loser at this point Not on a time scale of 100 years or so, let alone the 100,000 years that are being imposed as a requirement on geologic storage. On that time scale recovering unburned fuel from reprocessing will be cheaper than mining and refining fuel. > France still does reprocessing because whatever is done with spent fuel is not that expensive Yes, particularly when you factor in that reprocessing gives you a source of additional fuel (most of the "spent" fuel removed from reactors is actually not spent, and reprocessing recovers it for future use) that, as noted above, is expected to be cheaper than mining it in the not too distant future. > the boondoggle It's not a boondoggle at all, it's a rational way of anticipating future nuclear fuel requirements, as above. It's certainly much more rational than requiring spent fuel to be stored for 100,000 years as if that was the only possible thing that could be done with it.
- pfdietz 3y ago
  > Not on a time scale of 100 years or so AT THIS MOMENT it's an economic loser. If you need reprocessed fuel in 100 years, by the miracle of nonzero interest rates you save money by doing it closer to then instead of right now. The cost of storing the fuel until then is low enough that this works out. > It's not a boondoggle at all, it's a rational way of anticipating future nuclear fuel requirements, as above. No, it's a waste of money to do it right now.
  - pdonis 3y ago
    > it's a waste of money to do it right now If you're allowed to store the current waste in a facility that's only good for 100 years or so, then yes. But not if you're required to store any waste you don't reprocess for 100,000 years.
    - pfdietz 3y ago
      Where does that requirement come from, though? If society is going to collapse in 100 years, I suggest the money be better spent preparing for the consequences of that, not worrying about whether the documentation on dry casks will satisfy some licensing requirement.