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Finland's plan to bury spent nuclear fuel for 100k years

bbc.com

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Re: Finland's plan to bury spent nuclear fuel for 100k years

#41

Post by phkahler »

acidburnNSA wrote: post #19
nabla9 wrote: post #15

Earlier quoted context omitted.

You have the numbers reversed. In spent nuclear fuel 96% of the mass is the remaining uranium is still usable. Spend nuclear fuel (=LEU) used in these reactors have almost all potential energy left. You can use them if you close the nuclear fuel cycle with fast neutron reactors. The downside of it is that they FNR's are also good for making fuel for nuclear weapons.

I don't have the numbers reversed. I'm talking about when a single atom actually undergoes fission, it releases 93% of its energy promptly as fission product kinetic energy, gamma rays, and neutron kinetic energy. An hour later, another 6% of the energy goes out as delayed betas and gammas. After that, only 1% remains to emerge as heat in the repository. What you're referring to is the fact that some reactors (aka br…

>> don't have the numbers reversed. I'm talking about when a single atom actually undergoes fission...

Well then maybe you should talk about the problem at hand, which is the stuff people are considering "nuclear waste" and wanting to bury.

Re: Finland's plan to bury spent nuclear fuel for 100k years

#42

Post by ScoobleDoodle »

acidburnNSA wrote: post #21
PinguTS wrote: post #18

Earlier quoted context omitted.

Burying things in the ground is not a solution. It's more an Ostrich policy.

Lots of scientists disagree strongly with your statement. "The conclusion that disposal is needed and that deep geologic disposal is the scientifically preferred approach has been reached by every expert panel that has looked at the issue and by every other country that is pursuing a nuclear waste management program." https://www.energy.gov/ne/articles/blue-ribbon-commission-am... One thing that drives me craziest of…

I think the people you're referring to want us to stop producing nuclear waste in the first place.

This approach of geological sequestration, while being the scientifically preferred solution, still has potential very negative consequences for some future generation many years in the future. By some people calling this safe, it enables the nuclear proponents to leverage that to say there is no issue with the waste so it's fine to create more.

Re: Finland's plan to bury spent nuclear fuel for 100k years

#43

Post by ilyt »

chrisbrandow wrote: post #31

“ The digital emissions from this story are an estimated 1.2g to 3.6g CO2 per page view” I’m a little surprised that the emissions are so high per page view. I’ve never looked at co2 emission calculations for web pages before, but this seems a little high.

napkin math on https://www.eia.gov/tools/faqs/faq.php?id=74&t=11

0.855 pounds/0.38kg of CO2 per kWh.

or 0.38g per Wh

so 3.6g would be ~9.4 Wh, let's assume 10Wh

Site takes ~700ms to render, . So it would need to consume the equivalent of over 5kW of compute for a second to get that amount of CO2 per view.

That assuming it would be 100% load, and not just "waiting on various network RTTs"

I think it's safe to assume it's pure bullshit, even including every device along the way

Re: Finland's plan to bury spent nuclear fuel for 100k years

#44

Post by phkahler »

Out_of_Characte wrote: post #6
pierat wrote: post #2

What 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.

I see what you did there.

Re: Finland's plan to bury spent nuclear fuel for 100k years

#45

Post by simmerup »

pintxo wrote: post #17
elif wrote: post #8

Personally 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.

How would this ever be acceptable, given that rockets have a failure rate that’s not zero?

The impossibility of getting an insurance policy to cover this downside probably makes it dead in the water unless a state starts doing it

Re: Finland's plan to bury spent nuclear fuel for 100k years

#47

Post by kuratkull »

elif wrote: post #8

Personally 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.

Kurzgesagt: "Why Don't We Shoot Nuclear Waste Into Space?" https://www.youtube.com/watch?v=Us2Z-WC9rao

Bad idea, it boils down to 1) too much of it (yes really, in an almost definitive sense) 2) exploding rockets + nuclear fuel is bad

Re: Finland's plan to bury spent nuclear fuel for 100k years

#48

Post by pfdietz »

soulbadguy wrote: post #34
pfdietz wrote: post #29

If we're burying spent fuel, that's a tacit admission that nuclear will not be powering the world, because a once-through fuel cycle with thermal reactors (like the ones used in Finland) powering the world runs out of cheap uranium very quickly. In any case, the lack of a geological repository for commercial high level waste in the US is mostly because there's no stakeholder who really needs it. Storing spent fuel in…

> the world runs out of cheap uranium very quickly. Citations ?

World uranium resource information is readily available. For example:

https://world-nuclear.org/information-library/nuclear-fuel-c...

gives a resource, as of 2017, of 8 million tonnes. Note that the recent expansion in uranium exploration didn't increase the resource very much.

A 3000 MW(th) thermal burner reactor uses about 250 tonnes of natural uranium per year.

https://material-properties.org/what-is-natural-uranium-cons...

To "power the world" (by which I mean provide, as heat, the 18 TW of current world primary energy consumption) would therefore require 6000 x 250 or 1.5 million tonnes of natural U per year.

It has long (like, since shortly after WW2) been known that powering the world with fission will require some kind of breeding, which implies some kind of reprocessing. If you are committed to that, burying spent fuel as is makes no sense.

Re: Finland's plan to bury spent nuclear fuel for 100k years

#49

Post by rektide »

Out_of_Characte wrote: post #6
pierat wrote: post #2

What 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.

This was one of the advantages of Integral Fast Reactor. It had on site pyroprocessing, which doesn't have the same nuclear proliferation risks. https://en.wikipedia.org/wiki/Nuclear_reprocessing#Pyroproce...

Re: Finland's plan to bury spent nuclear fuel for 100k years

#50

Post by penteract »

chrisbrandow wrote: post #31

“ The digital emissions from this story are an estimated 1.2g to 3.6g CO2 per page view” I’m a little surprised that the emissions are so high per page view. I’ve never looked at co2 emission calculations for web pages before, but this seems a little high.

It's including the amount used by your machine while viewing the page, so if you're using a desktop with a 500W PSU (and you're using all 500W, which is probably an overestimate) and you spend a minute reading the article, that's 30kJ, which is roughly 1/2 a gram of methane[1], so roughly a gram of CO2 (more if it's coal, more if you take into account the fact that generators don't capture all the energy as electricity).

[1]https://en.wikipedia.org/wiki/Methane#Combustion

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