Could the Sun be used to dispose nuclear fission waste??

[Lord Baal]

Ok, I know this is kind of silly, but IF the price where reasonable, could be the sun used as a dumpster for fission waste?

I think it would not, of course I'm not a astrophysicist, so I wonder about this possibility. But also have some questions other questions related to this:

How much does it cost the current disposal methods per kilogram?

How much will cost sending of matter to the sun per kilogram?

Would there be any consequences on sending this kind of material to the sun?

I instinctively think that from the astrophysics point of view there's no risk (beyond a rocket with tons of radioactive material malfunctioning and exploding, becoming a very messy bomb :S ) involved in this. The difference of volume of the bodies involved, it would be like a drop on the ocean. What do you think?

[Iroscato]

Hmm, there was a topic exactly like this a few months ago...use the search function next time you make a new topic.

[Lord Baal]

I did, didn't find it. On the internet there's are some pages and articles, all say it's very costly so is impractical. I would like to know what if it's practical...

[Sea Skimmer]

Go look up how much space launches have failed; the whole idea is stupid, unsafe as well as too costly and totally pointless. The real waste we have a problem with is liquid stuff anyway, not the spent fuel rods everyone talks about which we could reprocess if not for massive stupidity in most nations who would rather see more toxic uranium mine waste created in foreign countries then bite the bullet on reprocessing.

[Lord Baal]

I did mention the possibility of a disaster using this method., but yet again, I'm interested more I what could happen if we [n]successfully[/n] manage to put those waste on the sun. What would happen [n]then[/n]? What would happen to the waste as it's getting closer to the sun? Is there any risk for us at that [n]point[/n]?

The cost questions where simply to know those things that have no real importance to the hypothetical case, but the main question remain. Could be the sun used as a dumpster for fission waste? What would happen if its so?

[Cykeisme]

If there's an accident that occurs near the ground during the launch, the explosion is going to disperse the waste over a pretty big area, depending on weather conditions.

Now, correct me if I'm wrong, but if the launch vehicle has a mishap in the upper atmosphere, that's just going to be much, much worse. Radioactive waste is going to get spread over a huge portion of the planet. The effect is going to be insanely horrible, likely far worse than a reactor containment breach.

Bad idea.

[Batman]

By the point space launches become economic and reliable enough to use for waste disposal my guess (mind you, a guess is all it is) would be we're long past using fission for power generation.
As for the negative side effects of dumping our fission waste products into the sun-there aren't any (at least for the sun, as others have mentioned, a lot of spent rods could actually reprocessed, which is sorta out the window in this scenario).
Why do you think there may be negative side effects of us dumping spent fissionables (or anything else, for that matter) into the sun?
I don't think you realize the massive mass difference between the sun and Earth (nevermind the fraction of Earth's mass that's actually fissionables, leave alone the portion we actually manage to convert into waste before we finally get fusion (or something even better) working, nor the incredible distances involved.
Let's assume that at a distance of 10 million km from the sun the radioactive waste (let's assume it's a thousand tons) decides to go 'screw fission, we'll go E=mc^2 just because we're feeling malevolent' (massively more than you'd get out of a fission or fusion reaction), that would result in the energy hitting Earth being...a goodly number of orders of magnitude lower than Earth receives in radiation from the sun as it is anyway.

The problem with dumping our fission waste into the sun was never, and never will be, it being dangerous (other than at the launch end).

[Lord Baal]

And finally thanks!!!! That was what I believed! I indeed pointed out the difference in volume (I forgot to mention the mass) between.

So there wouldn't be any risk to earth if we dump "massive"(relative speaking for us) amounts of nuclear waste to the sun. There's no chance of the thing blowing up and particles going back to earth or something... And yes, by the time is cheap enough we probably will be using other power sources... Thanks again.

[Eternal_Freedom]

If it blows up in space somewhere, harmful radiation getting back to us will be precisely jack diddly squat comparaed to the usual solar wind.

Biggest problem is cost. Space launches are expensive as is, and that's just to Earth orbit. If we want to launch a lot of waste, we'll also have to launch all the shielding needed to stop that waste being harmful on the ground. That means huge payloads and massive rockets, or small payloads and dozens of launches. Either way is expensive and dangerous (One big launch going wrong will seriously fuck up the area around it. On the flip side, a small launch going wrong is less bad but statistically more likely).

[Darth Wong]

What would be the point of dumping it into the Sun? You could just launch it in any random direction and it would be fine. It's still a stupid idea because of the risk of something going wrong on the liftoff. You can't just wave your hands and say "more advanced in future". There's always a risk. You're better off simply burying it in a really deep hole. The biggest reason why we can't do this is hysterical fearmongering. The fearmongering even becomes self-fulfilling: much of the radiation released from Fukushima was because spent fuel was stored on-site rather than being moved to a geologically stable storage site, because nobody likes the idea of a geologically stable storage site. So there was this big pile of spent fuel sitting there, right in the path of the wave. And then same people who opposed any kind of storage site went apeshit and said that Fukushima proved them right.

[Lord of the Abyss]

What would be the point of dumping it into the Sun? You could just launch it in any random direction and it would be fine.

Probably better; IIRC the Sun is the energetically hardest spot to reach in the Solar system from Earth. It would be easier to just shoot it out of the system past escape velocity. Not that we should; it's safer to just bury it, and what if we actually want to use it in the future? Hard to do that if it's past Pluto.

[FedRebel]

Isn't 'feeding' a G-type main sequence star (which kind of, sort of, DIES after it's mostly made up of iron) transuranic elements a very bad idea anyway? Sure comparative "trace" amounts shouldn't do much harm, but over the course of time continued transuranic dumps into the sun are going to accumulate until we reach that magic point wear solar fusion begins struggling (the sun will then swell into a red giant, swallowing the inner solar system before shedding itself into a white dwarf)

I can't see how in any sense this is a good idea, even if hypothetically we perfect space travel the objective is catastrophically counterproductive in the long run.

[CaptainChewbacca]

All the nuclear waste earth produces in a century is less than 1% of the transuranics the sun absorbed during its initial formation. Thats not an issue.

You've been watching too much Stargate.

[andrewgpaul]

Are they even going to make it into the core in a meaningful timeframe? I mean, a few uranium atoms bouncing about in the photosphere aren't going to affect the fusion in the core, after all.

[Hamstray]

Better and more realistic idea: dump the spent fuel rods inside a fusion reactor. That will also provide an energy boost.

[MrDakka]

Better and more realistic idea: dump the spent fuel rods inside a fusion reactor. That will also provide an energy boost.

How's this supposed to provide an energy boost? Transuranium elements are too massive to fuse.

[Hamstray]

How's this supposed to provide an energy boost? Transuranium elements are too massive to fuse.

for the gazillionth time: uranium 238 is fissionable by fast neutrons from the fusion reaction.

[Eternal_Freedom]

What would be the point of dumping it into the Sun? You could just launch it in any random direction and it would be fine.

Probably better; IIRC the Sun is the energetically hardest spot to reach in the Solar system from Earth.

I'm curious, why is the Sun, at the bottom of the gravity well, the energetically hardest point to reach? Surely if you give it a kick sufficient to get it out of Earth's immediate vicinity it will fall into a decaying solar orbit?

Presumably, launch it to just beyond the Earth-Sun L1 point and leave it to fall in on it's own.

[Eternal_Freedom]

Thanks for explaining that DXIII, it's been puzzling me for some time why it's easier to fly out of a gravity well than into it.

[MrDakka]

for the gazillionth time: uranium 238 is fissionable by fast neutrons from the fusion reaction.

My bad, I thought you were somehow expecting U-238 to somehow fuse ; completely overlooked fast fission.

On a side note, are there any fusion reactors today that can reach or exceed the break even condition? And if not, would it be possible to use fissionable but not fissile materials to boost the power output of reactors utilizing D-T fuel cycle? Seems like a waste of neutrons.

[StarSword]

On a side note, are there any fusion reactors today that can reach or exceed the break even condition?

Yes there are, mainly the magnetic-confinement type. The trick is getting them to exceed the break-even condition for more than a few seconds.

[Hamstray]

And if not, would it be possible to use fissionable but not fissile materials to boost the power output of reactors utilizing D-T fuel cycle? Seems like a waste of neutrons.

As opposed to neutrons leaving the core needing to be contained by expensive gadolinium?

[Zixinus]

No point.

If it blows up in space somewhere, harmful radiation getting back to us will be precisely jack diddly squat comparaed to the usual solar wind.

That depends on when it blows up: if it blows up while the rocket has archived Earth-orbit escape velocity, essentially you won. That radiation won't be going back to us.

If it blows up while still halfway from getting orbit-leaving velocity, then the container will eventually drift back, burn up in the atmosphere and disperse widely. Not the best scenario, but fairly harmless as the distribution of the materials will be very wide.

Isn't 'feeding' a G-type main sequence star (which kind of, sort of, DIES after it's mostly made up of iron) transuranic elements a very bad idea anyway?

Not really. You could feed Earth, the Moon and every rocky planet in-between and the Sun would be fine.
Besides, the Sun probably already has a massive pile of transuranic elements. Adding what amounts a few specks more won't do much.

On a side note, are there any fusion reactors today that can reach or exceed the break even condition? And if not, would it be possible to use fissionable but not fissile materials to boost the power output of reactors utilizing D-T fuel cycle? Seems like a waste of neutrons

There is (one, I think that's actually built).

I don't think that it would work.

Fusion is the combing lighter atoms into heavier atoms, a process that releases energy. Essentially any element lighter than iron can be fused to create energy.

Fission is the opposite: it uses super-heavy elements and fissile materials to have heavy atoms split and release energy.

Putting fissile elements into the middle of a fusion reactor will likely mess with the fusion process, if not outright grind it to a halt.

If not, then you have the problem of the neutrons being too energetic. Unless I got my physics wrong, I think it might only just heat up the fissile material, not make it fission.
Oh, and that's not even mentioning the problem of how the hell will you control this reaction to prevent your fusion reactor to become a meltdown.

Besides, at that rate, you might as well just put a heat-exchange cycle atop some concentrated radioactive waste and plug it into a heat engine. Neutrons create heat and that's to my knowledge the only way to gain energy from them.

At which rate, you might actually use a reprocessing fission reactor.

[Korto]

Out of idle curiosity, if you did dump spent rods into the sun:
Would it eventually reach the core?
How long would it take?

[Omeganian]

Out of idle curiosity, if you did dump spent rods into the sun:
Would it eventually reach the core?
How long would it take?

Well, for starters, they'll vaporize...