4 ms·

Do you think those aren't solved problems? First, fast reactors yield waste products that principally live only a couple of hundred years. [1] And even to answe

Do you think those aren't solved problems? First, fast reactors yield waste products that principally live only a couple of hundred years. [1] And even to answer your original question directly, there's a whole area of study that's fascinating on how to provide long-term warnings. [3] Not necessarily in the Australian outback, Yucca Mountain is a great choice. [2] [edit](That area is adjacent to the Nevada Test Site which is already some of the most radioactive land on earth). What greed exactly are you talking about? I've no financial interest in the success of nuclear power. I recognize it's more expensive than some competing options but it's a better solution. As for hubris, again, you're not exactly coming to the table with data on the risks, especially since we've got 80 years of experience with nuclear power. [1] https://en.wikipedia.org/wiki/Fast-neutron_reactor https://en.wikipedia.org/wiki/Fast-neutron_reactor [2] https://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_repository https://en.wikipedia.org/wiki/Yucca_Mountain_nuclear_waste_r... [3] https://en.wikipedia.org/wiki/Long-term_nuclear_waste_warning_messages https://en.wikipedia.org/wiki/Long-term_nuclear_waste_warnin...

jsmith45 4y ago
Exactly right. The goal with nuclear waste is basically to get it back down to levels similar the original ore. At that point, it isn't especially dangerous. Many radioactive products are either very short lived, and will decay down to minimal levels within a few hundred years, or are very long lived, causing very low radioactivity. The problem are the elements that are in between which is mostly the other actinides. Those are the ones that would require tens of thousands of years or more to reach safe activity levels. Fast reactor designs don't have significant amounts of such elements in the waste. The waste will decay to uranium ore-ore like levels within only hundreds of years. The biggest issue is that they need relatively enriched uranium to operate at first. After they are started, they can be used as a breeder reactor that can take in natural uranium and convert it to the enriched uranium it needs to continue running.
markvdb 4y ago
> fast reactors yield waste products that principally live only a couple of hundred years. Hundreds of years is not acceptable. Humanity is not able to handle projects spanning hundreds of years time. Look at the Zaporizhia atomic energy site for an extreme example of what I mean. The problem is not just the time scale either. There are other areas humanity fails at time and again. P.S. Thank you nevertheless for pointing out several advantages of fast breeder reactors.
- gattilorenz 4y ago
  > Humanity is not able to handle projects spanning hundreds of years time. There's plenty of buildings that took centuries to make, this projects are comparatively simple/require less coordination once started.
pfdietz 4y ago
Fast reactors are also in principle subject to Chernobyl-like criticality accidents (only worse) in case of meltdowns.
- arcticbull 4y ago
  I mean, any bad design is subject to failure. Aircraft are subject to catastrophic failure too, so we iterate and improve until they're super safe.
  - pfdietz 4y ago
    Fast reactor inherently have more fissionable material in a smaller volume, and don't have a moderator that can either keep things separated or remove itself in an accident to kill the chain reaction. If a supercriticality on prompt neutrons alone occurs in a fast reactor the neutron population will increase orders of magnitude faster than in a thermal reactor, because the neutrons are moving so much faster. Edward Teller in 1967 famously expressed his skepticism about fast reactors because of this safety issue.
    - arcticbull 4y ago
      That's not the argument I was making. I said anything of sufficient scale carries significant risk, and we can in time reduce that risk to acceptable levels via engineering practices and principles. As with airplanes, which are metal tubes full of humans we load up with kerosene and send into the atmosphere. A bad plane will crash, a bad reactor will melt down. We can overcome the risks to reap the rewards. That's like our whole thing, as humans. Chernobyl happened for a very specific reason - you know, the late-night tests and the positive void coefficient. Do you think we haven't learned? Please cite sources. The thing is, we have learned. That's why reactors are so expensive. You're double-dipping by citing the risks and the costs. It's really one or the other if you're not being disingenuous.
      - pfdietz 4y ago
        It's not the argument you were making, but it's a point your argument is compelled to address. Yes, any system of sufficient scale carries risks. In the case of breeder reactors, one of those risks is the possibility of something approaching an actual nuclear explosion, with fast neutron physics similar to what happens in actual fission bombs, not pitiful low yield moderated explosions as happened in Chernobyl.

jsmith45 4y ago

Exactly right. The goal with nuclear waste is basically to get it back down to levels similar the original ore. At that point, it isn't especially dangerous. Many radioactive products are either very short lived, and will decay down to minimal levels within a few hundred years, or are very long lived, causing very low radioactivity. The problem are the elements that are in between which is mostly the other actinides. Those are the ones that would require tens of thousands of years or more to reach safe activity levels. Fast reactor designs don't have significant amounts of such elements in the waste. The waste will decay to uranium ore-ore like levels within only hundreds of years. The biggest issue is that they need relatively enriched uranium to operate at first. After they are started, they can be used as a breeder reactor that can take in natural uranium and convert it to the enriched uranium it needs to continue running.

markvdb 4y ago

> fast reactors yield waste products that principally live only a couple of hundred years. Hundreds of years is not acceptable. Humanity is not able to handle projects spanning hundreds of years time. Look at the Zaporizhia atomic energy site for an extreme example of what I mean. The problem is not just the time scale either. There are other areas humanity fails at time and again. P.S. Thank you nevertheless for pointing out several advantages of fast breeder reactors.

gattilorenz 4y ago
> Humanity is not able to handle projects spanning hundreds of years time. There's plenty of buildings that took centuries to make, this projects are comparatively simple/require less coordination once started.

pfdietz 4y ago

Fast reactors are also in principle subject to Chernobyl-like criticality accidents (only worse) in case of meltdowns.

arcticbull 4y ago
I mean, any bad design is subject to failure. Aircraft are subject to catastrophic failure too, so we iterate and improve until they're super safe.
- pfdietz 4y ago
  Fast reactor inherently have more fissionable material in a smaller volume, and don't have a moderator that can either keep things separated or remove itself in an accident to kill the chain reaction. If a supercriticality on prompt neutrons alone occurs in a fast reactor the neutron population will increase orders of magnitude faster than in a thermal reactor, because the neutrons are moving so much faster. Edward Teller in 1967 famously expressed his skepticism about fast reactors because of this safety issue.
  - arcticbull 4y ago
    That's not the argument I was making. I said anything of sufficient scale carries significant risk, and we can in time reduce that risk to acceptable levels via engineering practices and principles. As with airplanes, which are metal tubes full of humans we load up with kerosene and send into the atmosphere. A bad plane will crash, a bad reactor will melt down. We can overcome the risks to reap the rewards. That's like our whole thing, as humans. Chernobyl happened for a very specific reason - you know, the late-night tests and the positive void coefficient. Do you think we haven't learned? Please cite sources. The thing is, we have learned. That's why reactors are so expensive. You're double-dipping by citing the risks and the costs. It's really one or the other if you're not being disingenuous.
    - pfdietz 4y ago
      It's not the argument you were making, but it's a point your argument is compelled to address. Yes, any system of sufficient scale carries risks. In the case of breeder reactors, one of those risks is the possibility of something approaching an actual nuclear explosion, with fast neutron physics similar to what happens in actual fission bombs, not pitiful low yield moderated explosions as happened in Chernobyl.