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Comment by PaulHoule | Hacker News Reader

... and then they'll dig it up and reprocess it when they really need the energy contained in it.

If it's anything like the Finnish facility there would be no digging, the facility has tunnels leading to the different storing locations. It will be continually used for centuries to place new spent fuel. They different rooms with spent fuel could easily be opened again.

Planned lifespan of ONKALO is around a hundred years, not multiple centuries.

A hundred years should be enough time to make enough renewable energy to replace nuclear.

...or have Covid 2055 that wipes out 90% of the population.

The Finnish site is based on the Swedish method (KBS-3 if you want to read more) so not only is it anything like it, they are the same :)

Sweden could have uranium mines themselves but don't want that dirty stuff happening in their own backyard, so buy fuel needed from other places (Canada, I think?)

Sweden used to have their own uranium mine, but since it was cheaper to buy it than to mine it they shut it down. Pretty sure most of it is purchased from Russia.

Yes, they just did start buying from Russia. It is a security concern these days and was discussed as recently as yesterday in Swedish media.

It's a security concern but it is not as big a one as Russian gas.

If you import 10 years of gas you import 10 years of gas.

If you import 10 years of uranium for the LWR you imported more like 1000 years of uranium for fast reactors.

Gas is difficult to ship long distances and dependent on pipeline networks. It is hard to substitute American or Middle Eastern gas for Russian gas but easy to replace Russian uranium with uranium from South Africa, Australia and many other places.

Could be. My unpopular prediction is that within 100 years, well-engineered deep-ocean burial will be considered good enough, given all else which is likely to become clear by then.

praying irrationally for shipping the junk to the moon.

that'll show em.

If you can get it to the moon isn't it almost as easy to just shoot it into the Sun?

Actually nope. It takes more energy to slow yourself down enough to crash into the sun, starting from the earth, than it does to hop on over to the moon.

Definitely a stupid question, because I actually have no idea how they work: can a solar sail be "tacked" so as to decelerate towards the sun, like a sailboat sailing into the wind?

(Setting aside the risky problem of getting this waste off earth and into space to begin with)

I have not done any calculations now, but given how small the solar wind is in drag, it would have to be a very, very big sail.

Tacking works because boats have a second "sail" interacting with a second fluid moving differently than the wind (the keel is in the water). There's no second thing to push against in space.

If you "tack" your solar sail, you'll spin.

It's a misconception that shooting things to the Sun is easy, it's actually extremely difficult due to the fact that when you launch off of the Earth, after escaping Earth's gravity you're left with ~30km/s of leftover momentum that you have to do something with in order to not wind up in an orbit around the Sun.

Why can't you just aim for a direct hit at 30km/s?

The exact same reason why planets don't immediately fall into the sun

The momentum you inherit from Earth isn't in the direction of the sun, but roughly perpendicular to that direction.

It's similar to a car going down the freeway at high speed that needs to make an immediate 90 degree right turn. It can't do that without slowing down first, if it did, it would slide sideways off the sideroad. It's harder in space because the car is going 30 km/s and there's no friction that slows you down.

That's not how orbital mechanics works. Objects move in elliptical orbits around the sun, not in straight lines.

https://space.stackexchange.com/a/45619

Imagine sitting on a huge carousel spinning fast, like 100 times the speed of sound fast. Now imagine jumping off and trying to get to the center of it.

Yes, gravity is holding us back from yeeting of into space but to get closer to the sun you need to slow down. A lot. It takes way less rocket fuel to speed up enough to leave the solar system than to get to the sun.

I think it would be a pretty big difference in delta-v.

https://upload.wikimedia.org/wikipedia/commons/9/93/Solar_sy...

There's a few major issues with disposing of nuclear waste into the sun. First and foremost is that if the rocket explodes you'll contaminate a huge radius with dirty bomb like material. Probably not great.

Further, if you do decide to launch it, it takes significantly more energy to shoot it out of the solar system than towards the sun. [1]

[1] https://www.forbes.com/sites/startswithabang/2019/09/20/this...

Did you mean to word that the other way around? It takes less energy to shoot it out of the solar system than towards the sun.

Ooof, good catch. Thank you, yes, that's what I intended to say. Too late to edit.

No. Getting to the Sun requires scrubbing off nearly all the orbital speed of the Earth (30km/s), or the payload just orbits at a smaller radius.

The delta v to the Moon is something like 7 times less than to the Sun (3 vs 20ish).

The delta v need of the Parker Space Probe, which still "only" gets to 8.5 solar radii is so high it will use 7 Venus assists to get it close enough (it can't do big Jupiter assists because the solar panels it would need at Jupiter wouldn't be able to fit behind the sun shield at perihelion, and they didn't want to give it an RTG because they're saving plutonium for future missions).

You can eventually hit the Sun with enough Venus assists and Earth assists, for a total delta v of under 4 km/s, but it'll take a very, very long time, and your nuclear waste will be doing Earth flybys until finally it hits the Sun. Also it might be tricky to get the ball of sun-melted radioactive slag to do accurate assists after the sun melts it on the last few close encounters.

why not mars? didn't falcon heavy do that with a car?

Yeah, water is a very good radiation shield, and seafloor gunk doesn't hurt. The concrete casks probably sink pretty easily too.

Also, salty seawater will eat through any metal at about the rate of a Windows 95 install process indicator. At that point, the nuclear gunk will disperse in the water, enter the food chain, and soon be part of your romantic lobster dinner. Enjoy!

The casks aren't metal on the outside, they're a specialized concrete. These casks have been dropped from building, exploded, struck by speeding trains, and burned at incredibly high temp all without losing integrity. Even still, uranium and similar waste products aren't water soluble and being more dense than any surrounding material so they would sink through the sediment and become locked in place. Here's a really old survey on the topic[1]. Here's another study [2]. Basically most of the waste would be short-lived beta and gamma emitters that are no longer dangerous after a few years. The longer lived alpha emitters aren't dangerous because alpha particles are easily stopped. You can safely hold a small amount of uranium in you hand.

With respect to ocean life, there is also very little life in these trenches, and what life there is doesn't mix with food chains at higher levels. All of the food comes from biological material sinking, and nothing really goes the other direction.

[1] https://www.iaea.org/sites/default/files/31404684750.pdf [2] https://www.swr.de/-/id=13132940/property=download/nid=23345...

Also, last time I estimated Bequerels (aka decays) in the ocean already, compared to what extremely dilute waste would add, well as I recall it was "a drop in the ocean."

Need to recheck this sometime.

Most of the talk about deep-ocean burial has assumed that we're burying (worthless) fission products.

Leftover uranium and plutonium in the fuel contains more than 95% of the energy from the original uranium so it is madness to bury it in a place we can't get it.

I was thinking about writing a science fiction story about the Mormons and Scientologists fighting over Yucca Mountain 2000 years from now but now I don't think the Scientologists are going to last that long.

Yes, in terms of eventual ocean burial, as one option, I was assuming after reprocessing, burning in a fast breeder or Moltex, etc.

This thought might be more for additional existence proof right now.

+1 for Moltex.

I presented at the first thorium energy conference put on by Kirk Sorenson and it has been breathtaking to watch the focus shift away from thermal to fast and fluoride to chloride and now static fuels.

Moltex really looks like the one and it will be wonderful if Canada develops a world-beating nuclear technology like what they attempted with CANDU.

To be fair, most people don't understand the storage problem. They think we have to store it for hundreds of thousands of years (ironically we don't think about this with plastics, heavy metals, or other products that don't decay). But it's storing for hundreds of thousands of years and assuming that the future civilizations don't know our language, we lost maps of these sites, and there's no reason to dig them up. This is left over cold war era thinking where WW3 brings us back to the stone age. But in reality it's fine to sit on the material, in place, and hope we figure out better things in the next few hundred years that we can safely do that. I've heard a complaint that this is passing the buck, like we did with climate, but I think that's only true if we assume no technological advancements. Or in other words, we stop researching. But also nuclear waste is a slowly building problem with a positive feedback loop so I think the comparison is bad anyways. In a few hundred years we'll probably pretty easily be able to extract the 95% of the energy that's left in our waste material and put it to good use. After all, France can already do a bit. It's just not cost effective for most because it's cheaper to mine than recycle.

> But in reality it's fine to sit on the material, in place, and hope we figure out better things in the next few hundred years that we can safely do that.

This is a very optimistic view. There are 56 nuclear power plants in the US alone. It is entirely believable that one or more of them will be shut down and then outright abandoned at some point in the next few hundred years, leaving nuclear waste with no long term containment story. Over the course of history, abandonment of once-important areas has been pretty common. I see no reason to believe it cannot happen to a nuclear plant.

I can easily imagine a plant being turned off and a future government deciding that it’s just not worth dealing with a proper decommissioning, so they just walk away. It’s easy to imagine this because it’s exactly the same stance you are proposing. “It’s good enough for now, someone else can deal with it later when magic (technical advancements) shows up.”

I’m also quite concerned about what happens if one of these “just store it on site” facilities gets bombed at some point.

> I've heard a complaint that this is passing the buck, like we did with climate, but I think that's only true if we assume no technological advancements.

Of course you’ve heard that complaint, because it is passing the buck. Betting on future technological advancements without actually investing in those technological advancements is 100% passing the buck.

> Over the course of history, abandonment of once-important areas has been pretty common. I see no reason to believe it cannot happen to a nuclear plant.

https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident

Of course, that wasn't waste.

It's a reason why we need to implement a solution for nuclear waste. With the carbon crisis the fear of proliferation is more dangerous than proliferation.

It's passing the buck but it also isn't a problem that needs to be solved for several hundred years. And you'll notice I said this isn't a problem as long as we keep researching, aka. not abandonment. My bigger point is that it wasn't like climate change where every day we ignore or don't solve the problem then the problem gets worse (a positive feedback loop). In the case of nuclear, this is not actually true. We also have a substantially larger timeframe to solve the problem. I believe it is naive to also believe that we can come up with a perfect storage solution (long term, doesn't rely on known languages, can handle apocalyptic events, loss of history, and many other factors that only matter when we're looking 10k years out). I think it is a bit naive to believe that a solution we could implement today would be a descent solution. It is better to continue researching and sitting on it (which is safe for now and the next few hundred years. Which is only unsafe because geological effects come into play). No matter what we do you can define it as "passing the buck" simply due to the underlying issue of humans being dumb.

You don't need to predict anything. It's already been done: https://en.wikipedia.org/wiki/Ocean_disposal_of_radioactive_...

We need it.

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