Finland's plan to bury spent nuclear fuel for 100k years
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Re: Finland's plan to bury spent nuclear fuel for 100k years
#2What I don't get is the following:
If your nuclear waste is that "hot" (highly radioactive), then you're not draining as much energy out of the material.
Ideally, the closer to lead you are, the more energy is drained out. And that's what I'd hope to see from the mining required for uranium. Instead, we seem to run it once and then go "whoop have to stop".
Re: Finland's plan to bury spent nuclear fuel for 100k years
#3I'm excited that Onkalo will be coming onine soon, so we don't have to hear the myth that there's no solution for spent nuclear fuel anymore. The solution that enjoys a solid scientific consensus is the deep geologic repository.
Another thing that is weird to me is that everyone says nuclear waste is hazardous for a uniquely long time, but it become less hazardous over time. Many non-radioactive materials, like arsenic and mercury, are toxic forever.
In the US we have WIPP operating, but it stores weapons-related radioactive material rather than commercial spent fuel, so I guess it doesn't count.
Re: Finland's plan to bury spent nuclear fuel for 100k years
#4What I don't get is the following: If your nuclear waste is that "hot" (highly radioactive), then you're not draining as much energy out of the material. Ideally, the closer to lead you are, the more energy is drained out. And that's what I'd hope to see from the mining required for uranium. Instead, we seem to run it once and then go "whoop have to stop".
Not sure I'm following. Fission reactors split uranium into smaller atoms like barium and krypton. The remaining energy that comes out as afterglow heat in the repository is a small fraction of what already came out during fission. less than 1% remains an hour after fissioning.
Re: Finland's plan to bury spent nuclear fuel for 100k years
#5How interesting, I was just reading about this in the context of nuclear semiotics and how to pass down warnings about the danger of nuclear waste. (This is a really interesting topic without much in the way of clear answers, depending on what you're optimising for. Highly recommend reading the Wikipedia page[0] at a minimum.)
There's apparently a documentary on this project, "Into Eternity," released in 2010, which has been on my list since earlier this morning (i.e., since I read about its existence).
0. https://en.wikipedia.org/wiki/Long-term_nuclear_waste_warnin...
Re: Finland's plan to bury spent nuclear fuel for 100k years
#6What I don't get is the following: If your nuclear waste is that "hot" (highly radioactive), then you're not draining as much energy out of the material. Ideally, the closer to lead you are, the more energy is drained out. And that's what I'd hope to see from the mining required for uranium. Instead, we seem to run it once and then go "whoop have to stop".
Yeah, you could reprocess spent fuel but one of the byproducts would be plutonium. So we'd rather bury everything than using the plutonium for other projects because of fear that we can't handle nuclear byproducts.
Re: Finland's plan to bury spent nuclear fuel for 100k years
#7The mechanical container solution is top notch, but 99% of the safety is just geological stability and selecting right place. Over 2 billion year old granite with very few cracks far from any fault lines.
The worst possible scenario they calculated:
1) the nuclear canister would corrode in a thousand years instead of the calculated hundred thousand years,
2) and at the same time installed clay buffer surrounding canisters would inexplicably disappear.
3) In addition, the groundwater would magically flow upwards and
4) a city would be built on the site. A person who would live on the most polluted square meter from cradle to grave and would only eat food grown there and drink the most polluted water
Result: people would only receive three times the radiation dose compared to people currently living in a city of Tampere.
Re: Finland's plan to bury spent nuclear fuel for 100k years
#8Personally I'm rooting for the future where a fleet of falcon 9's launch escape velocity stage 2's that head straight for the sun.
Underground is nice until you get radioactive groundwater. The time cost of 100k years of maintaining safety seems more than the financial cost of maintaining a F9 fleet and disposing of second stages.
Re: Finland's plan to bury spent nuclear fuel for 100k years
#9Personally I'm rooting for the future where a fleet of falcon 9's launch escape velocity stage 2's that head straight for the sun. Underground is nice until you get radioactive groundwater. The time cost of 100k years of maintaining safety seems more than the financial cost of maintaining a F9 fleet and disposing of second stages.
Until one of them fails to launch or reach orbit
Re: Finland's plan to bury spent nuclear fuel for 100k years
#10What I don't get is the following: If your nuclear waste is that "hot" (highly radioactive), then you're not draining as much energy out of the material. Ideally, the closer to lead you are, the more energy is drained out. And that's what I'd hope to see from the mining required for uranium. Instead, we seem to run it once and then go "whoop have to stop".
There are three issues with trying to get more energy out of hot 'spent' fuel rods
(1) the radiation levels increase, making it more dangerous for workers to do maintenance and safety operations (so overall reactor design would need to take this into account),
(2) some fission products and transuranics (plutonium etc.) act as neutron poisons (absorbing neutrons rather than generating energy-productive fission events), resulting in reduced reactor output and instability issues as the accumulate in the fuel rods.
(3) since you are actually transmuting elements, physical and chemical changes take place resulting in fuel rod corrosion and degradation, swelling and structural changes, etc. which could lead to catastrophic failure by clogging the reactor core and preventing coolant circulation.
[edit] note that reprocessing the spent fuel (plutonium recovery) for use in MOX reactors is possible, but since this is also how you run a nuclear weapons program, there are additional concerns and the costs are really high:
https://world-nuclear.org/information-library/nuclear-fuel-c...