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Comment by whycome | Hacker News Reader

It’s a constant heat producer. Can’t we use it just for that? Store it somewhere and transfer the heat with traditional liquid cooling/heat exchanger methods? Store it up in the permafrost regions. Heat greenhouses.

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Radioactive materials that produce enough heat to warm a greenhouse in a conveniently sized package are extremely hazardous if uncontained. It's relatively easy to encapsulate radioactive materials against accidental exposure, but much harder to guard against misinformed or malicious deliberate exposure. Then you get expensive and lethal incidents like these:

https://en.wikipedia.org/wiki/List_of_orphan_source_incident...

I don’t really foresee it being packaged out. But maybe a heat exchanger that uses the main long term storage pile

The Soviets did this with RTGs for remote on site power production. They're now abandoned and dangerous sources of nuclear material for those with evil intent.

Ok, but couldn't we just do the part where we somehow extract usable energy from nuclear waste without the subsequent abandonment?

The Soviet Union wasn't exactly intending to fall apart, and yet it did.

If you look at the current state of US politics, it should be pretty obvious that we can't even count on the richest and most advanced countries to remain stable for even a couple of decades: your "no abandoning nuclear sources" policy can be completely gone in the blink of an eye.

When it comes to something as dangerous as nuclear material you should hope for the best but plan for the worst. Using latent heat might be a neat idea in a best-case scenario, but quickly turns into an absolute nightmare in a worst-case scenario.

Theoretically yes, but you seriously complicate the storage of nuclear materials when you start packing it all together and trying to create heat or keep it at any elevated temperature for harvesting heat. That is basically the entire concept of a nuclear reactor, except now its either a random mash of nuclear stuff unless you spend a ton of money categorizing and actively monitoring the state of all the material put in, but with a less robust cooling system than an actual nuke plant and far lower output.

With the expenses involved with all of that, it would probably be better to just build multiple geothermal plants instead and you don't have to worry about nuclear materials at all for similar power output.

To me the only 2 economically feasible strategies I see with high level nuclear waste is recycling with some sort of breeder reactor program, or dumping it in a deep stable hole that is trapped away from any water tables on the order of 100,000 years or more, by which point it will just be a uniquely rich and and diverse nuclear mineral deposit.

With a breeder reactor though and all the supporting nuclear reprocessing facilities, even though it would be a lot of work and money, it would be recovering the vast majority of potential energy from previously mined and refined nuclear materials that you are talking about recovering heat from, and in a far more controlled manner that allows us to just chuck the material into pretty much any other reactor without any significant modifications.

I had considered submitting a YC application for a startup that would do this, take waste radioactive material and turn it into uniform physical pellets or cubes for district heating via vitrification, but it seemed like between the capital costs and regulatory hurdles, it's just really, really hard to make commercial economics work. At least with electrical generation with nuclear, you can get some buy in from people willing to tie up billions of dollars for decades even with a high risk of failure, or get someone with deep pockets like big tech to sign a power purchase agreement for existing nuclear capacity.

If the waste has to sit somewhere generating heat, might as well get some value from it.

(global district heating TAM is only ~$200B, idea sprung from xkcd spent fuel pool what if: https://what-if.xkcd.com/29/)

So your business plan is commoditization (democratization?) of dirty-bombs, backed by a pop-sci science comic, with the only remaining problem to overcome (apart to getting funding) is the regulation... that involves state-level-actors even start wars and bombings if needed, to stop this kind of contingency?

When will there be an IPO?

Vitrified low grade nuclear waste weighing several tons submerged in a liquid medium for heat exchange in an underground facility poses limited risk assuming physical access controls. The containers are otherwise simply buried in a permitted trench and covered with soil.

https://www.hanfordvitplant.com/low-activity-waste-law-vitri...

by vitrification you mean the radioactive material is turned into glass cubes for the storage/distro?

And yeah, that was my thought re: 'might as well get some value from it' I mean what if that heat transfer was mostly passive? So that a nuclear waste storage depot in the arctic creates some other value.

Yep, the waste is turned into an insoluble glass product to stabilize it for long term storage.

https://www.hanfordvitplant.com/vitrification-101

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

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