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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

#61

Post by pfdietz »

nabla9 wrote: post #15
acidburnNSA wrote: post #4

Earlier quoted context omitted.

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.

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.

That 96% of the mass is 238U. It's usable in breeder reactors. It's not useful for today's burner reactors. We have far too much 238U for those already; enrichment is the process of stripping out 238U from natural uranium. It would be utterly pointless to recover more 238U for them. We already have great stockpiles of depleted U sitting around. The stuff is not worth very much right now.

Reprocessing can recover some plutonium, which can be reused (once more) in MOX fuel. Spent MOX fuel cannot be reprocessed further for use in today's thermal reactors, though.

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

#62

Post by pfdietz »

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.

Falcon 9s are still too expensive, especially if you want to armor the spent fuel in case of launch failure.

Disposal of troublesome fission products and actinides, on the other hand, could be much easier. There are seven fission products with troublingly long half lives that would be difficult to retain in geological repositories. Extraction and space disposal of the elements of those isotopes could make sense.

In any case, space disposal can wait until launchers are mature and the technology has stopped improving. We have centuries before spent fuel stops being self-protecting against diversion due to its radioactivity, so stick the stuff in dry casks and wait.

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

#63

Post by pfdietz »

pfdietz wrote: post #48
soulbadguy wrote: post #34

Earlier quoted context omitted.

> 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-urani…

There's a question of how cheap "cheap" has to be. But saying "uranium cost doesn't matter because capital cost of the power plants is so much larger" is a left-handed argument.

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

#64

Post by iso1631 »

PinguTS wrote: post #38
iso1631 wrote: post #24

Earlier quoted context omitted.

As Ostrich policy is ignoring the problem -- specifically not looking at the problem. Burying the Geiger counters would be an Ostrich policy

It is exactly that. We are putting it deep into the ground and ignoring the problem.

My guniea pigs hide from predators by burying themselves in hay. It's fairly effective.

That's not what as Ostrich does. An Ostrich leaves itself exposed and just closes its eyes.

Mankinds attitude to all sorts of threats is an ostrich policy, but burying nuclear waste is not one of those. Leaving it in a barrel and saying "nothing to see here" would be.

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

#65

Post by aPoCoMiLogin »

PinguTS wrote: post #32
acidburnNSA wrote: post #21

Earlier quoted context omitted.

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…

The thing is, that to human knowledge it is currently the only viable way to handle the situation. But still it is not a solution. A solution would be to make it non-hazardous. But there is no viable way to do it right now.

highly recommended to watch https://www.youtube.com/watch?v=4aUODXeAM-k

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

#66

Post by linksnapzz »

this_user wrote: post #40
linksnapzz wrote: post #23

Earlier quoted context omitted.

Burying things securely until a better solution can be found is a better than letting them sit onsite in storage pools...

"Securely" being the key term here. Something that is buried securely today may not be buried securely tomorrow, or in 100 or a 1000 years, because the geology of the planet is not static. This can become even more of a problem if the knowledge should be lost what was buried where.

The subterranean geology of granitic shield provinces doesn't change much over the course of ...human-accessible timescales.

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

#67

Post by linksnapzz »

phkahler wrote: post #35
linksnapzz wrote: post #23

Earlier quoted context omitted.

Burying things securely until a better solution can be found is a better than letting them sit onsite in storage pools...

But may not be better than shutting it all down.

Sorry, I like reliable electricity, I don't live near a hydro plant, and I'd prefer not to burn coal. Nuclear does what I want, and if the desire for a perfect solution for waste handling gets in the way of a good method for keeping the lights on while we work towards improving the isolation and transmutation of waste-that desire needs to be set aside.

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

#68

Post by linksnapzz »

PinguTS wrote: post #36
linksnapzz wrote: post #23

Earlier quoted context omitted.

Burying things securely until a better solution can be found is a better than letting them sit onsite in storage pools...

I agree to in way that this is currently the only viable way to handle the situation. But it is not a solution.

"Live in Idaho" isn't THE solution to deaths from tropical diseases; but let's not pretend that it isn't A solution...

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

#69

Post by pdonis »

pfdietz wrote: post #59
pdonis wrote: post #52

Earlier quoted context omitted.

> 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_s...

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 exp…

> 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.

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

#70

Post by pdonis »

pfdietz wrote: post #59
pdonis wrote: post #52

Earlier quoted context omitted.

> 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_s...

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 exp…

> That list includes the US, which hasn't had commercial reprocessing in many decades.

But it also includes many countries that reprocess currently.

The US has not reprocessed fuel in many decades, and never on any significant scale, because the Carter Administration outlawed it based on mistaken concerns about proliferation, and it's been a political pariah ever since. It has nothing to do with any rational technical assessment.

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