3 ms·

Ten Thousand Years (2014)

27 points by rahuldottech 8y ago

dang 8y ago
Discussed at the time: https://news.ycombinator.com/item?id=8090759 https://news.ycombinator.com/item?id=8090759
Symmetry 8y ago
I wonder how radioactive this waste would be after just 1,000 years and if that's a level we really need to worry about people being exposed to. That is, how long will it take for the waste to become less dangerous than naturally occurring asbestos deposits, say?
- tcmb 8y ago
  It depends on which elements it contains exactly. The isotope Plutonium-239, often used in nuclear weapons, has a half-life of ca. 24.000 years, meaning that after 24.000 years, half of the material is still the same isotope, while the other half will have decayed to other elements. https://en.wikipedia.org/wiki/Radioactive_decay https://en.wikipedia.org/wiki/Radioactive_decay https://en.wikipedia.org/wiki/Radioactive_waste https://en.wikipedia.org/wiki/Radioactive_waste
  - Koshkin 8y ago
    > other elements ...some of which, too, are pretty nasty: Plutonium-239 → Uranium-235 → Thorium-231 → Protactinium-231 → Actinium-227 → Thorium-227 → Radium-233 → Radon-219 → Polonium-215 → Lead-211 → Bismuth-211 → Thallium-207 → Lead-207
  - Symmetry 8y ago
    The thing about things with longer half lives is that while they last a longer time they're also less radioactive. The same decay events that cause dangerous radiation are the same decay events that lead to the material's half life. I would guess that it's worse to breath in Plutonium-239 than to breath in asbestos but I'm not sure and the Wikipedia page is short on information that would convince me either way. https://en.wikipedia.org/wiki/Plutonium#Toxicity https://en.wikipedia.org/wiki/Plutonium#Toxicity
lurquer 8y ago
This may sound counterintuitive, but perhaps the best way to warn future generations of the danger of the area would be to make the area MORE dangerous. That is, install a highly radioactive cube of something that will kill -- very quickly -- anyone who comes within a mile or two of the site. People will learn to avoid the area very quickly.
roenxi 8y ago
We saw an article on this subject the other day [0]; rehashing what I said there: This is an intellectually interesting problem, but not a practical one. There are two scenarios: 1) Society is similar or more advanced than we are - they'll figure out what is going on pretty quickly. Any damage done is irrelevant given that human population is measured in billions. It would be like someone falling in to old mine workings today - to be prevented, but not something the original miners need to feel responsible for. 2) Society has regressed to the point where they no longer understand what nuclear waste is - discovering a radioactive waste dump will be a boon to their scientific efforts and they'll be so busy hailing the people who discover the magic rock as heroic discoverers that they won't be worried about the cost. We're going to leave behind some much nastier residues than nuclear waste with longer half lives. There is not a single practical issue that a human would worry about 10,000 years ago that is relevant to us today. That length of time isn't something civilization copes with. [0] https://news.ycombinator.com/item?id=19763131 https://news.ycombinator.com/item?id=19763131

27 points by rahuldottech 8y ago

dang 8y ago

Discussed at the time: https://news.ycombinator.com/item?id=8090759 https://news.ycombinator.com/item?id=8090759

I wonder how radioactive this waste would be after just 1,000 years and if that's a level we really need to worry about people being exposed to. That is, how long will it take for the waste to become less dangerous than naturally occurring asbestos deposits, say?

tcmb 8y ago
It depends on which elements it contains exactly. The isotope Plutonium-239, often used in nuclear weapons, has a half-life of ca. 24.000 years, meaning that after 24.000 years, half of the material is still the same isotope, while the other half will have decayed to other elements. https://en.wikipedia.org/wiki/Radioactive_decay https://en.wikipedia.org/wiki/Radioactive_decay https://en.wikipedia.org/wiki/Radioactive_waste https://en.wikipedia.org/wiki/Radioactive_waste
- Koshkin 8y ago
  > other elements ...some of which, too, are pretty nasty: Plutonium-239 → Uranium-235 → Thorium-231 → Protactinium-231 → Actinium-227 → Thorium-227 → Radium-233 → Radon-219 → Polonium-215 → Lead-211 → Bismuth-211 → Thallium-207 → Lead-207
- Symmetry 8y ago
  The thing about things with longer half lives is that while they last a longer time they're also less radioactive. The same decay events that cause dangerous radiation are the same decay events that lead to the material's half life. I would guess that it's worse to breath in Plutonium-239 than to breath in asbestos but I'm not sure and the Wikipedia page is short on information that would convince me either way. https://en.wikipedia.org/wiki/Plutonium#Toxicity https://en.wikipedia.org/wiki/Plutonium#Toxicity

lurquer 8y ago

This may sound counterintuitive, but perhaps the best way to warn future generations of the danger of the area would be to make the area MORE dangerous. That is, install a highly radioactive cube of something that will kill -- very quickly -- anyone who comes within a mile or two of the site. People will learn to avoid the area very quickly.

roenxi 8y ago

We saw an article on this subject the other day [0]; rehashing what I said there: This is an intellectually interesting problem, but not a practical one. There are two scenarios: 1) Society is similar or more advanced than we are - they'll figure out what is going on pretty quickly. Any damage done is irrelevant given that human population is measured in billions. It would be like someone falling in to old mine workings today - to be prevented, but not something the original miners need to feel responsible for. 2) Society has regressed to the point where they no longer understand what nuclear waste is - discovering a radioactive waste dump will be a boon to their scientific efforts and they'll be so busy hailing the people who discover the magic rock as heroic discoverers that they won't be worried about the cost. We're going to leave behind some much nastier residues than nuclear waste with longer half lives. There is not a single practical issue that a human would worry about 10,000 years ago that is relevant to us today. That length of time isn't something civilization copes with. [0] https://news.ycombinator.com/item?id=19763131 https://news.ycombinator.com/item?id=19763131