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With the rising bulk energy consumption and the CO2 problem, nuclear plants appear once again to be a feasible long term source of (industrial) energy.

However a big show stopper is the problem with the radioactive waste which we have to store and isolate possibly for millions of years. As of 2010, there must have been 250 kt of it globally. It might get better if fusion energy becomes largely available, but also in this case you will have to deal with "removable parts'" remaining for 200 years or so.

Given launch prices will become cheap, who knows, maybe one day it might become economically feasible to transport radioactive waste to space where it can be put on say Venus or maybe better in the Sun (given acceptable launch safety levels can be guaranteed!). For sure this is an economic equation where however you make the case against those millions of years mentioned above.

Now my question: is there any scientific research/concepts for that? Is there an estimation of how low the launch price must become to make this topic less of science fiction babble? (Who knows maybe after all, nuclear plants plus space waste dump is really nonsense as compared to orbital solar cells plus microwave energy downstream)

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    $\begingroup$ There's several parts to an answer 1) how will cost per ton drop over time, 2) how low will it have to drop to be a competitive method of waste disposal, and 3) how safe/reliable will the launch have to be; if it fails at some point, where will the nuclear waste land and what problems will that cause? $\endgroup$
    – uhoh
    Oct 13 at 8:11
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    $\begingroup$ You should clarify what you mean by radioactive waste. Only burned nuclear fuel or also parts of decommissioned nuclear power plants (for example reactor pressure vessel, fuel rods). Curious what can be total mass of burned uranium which is stored in spent fuel pools. It should be only very small part of total radioactive waste mass. But since it is always most radioactive part and only small part from total RW mass, it could be worth it. Launch of course must take place from remote area (like isolated pacific island) to limit fallout in case of potential launch failure. $\endgroup$
    – David Cage
    Oct 13 at 11:29
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    $\begingroup$ @David Cage launch from a remote site might help limit risk, but there would remain a risk that some sort of failure would leave the rocket in the wrong orbit (this has happened on a number of occasions). This might well lead to an uncontrolled re-entry almost anywhere on Earth leading to radioactive contamination of the atmosphere and/or the surface. $\endgroup$
    – Slarty
    Oct 13 at 15:25
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    $\begingroup$ The problems with containing nuclear waste on Earth aren't technical but rather political. Nevada politicians make a show of opposing the Yucca Mountain Project on the basis that the DOE can't prove it will contain waste safely for ten thousand years while supporting any number of policies likely to be disastrous in the next fifty. As for space disposal, the environmental consequences of one failed launch carrying nuclear waste could be horrific as well; it's simply a bad idea. $\endgroup$ Oct 13 at 16:25
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It seems likely that launch costs may reduce in the years to come, especially if SpaceX’s Starship meets expectation, however this is not guaranteed and even if it does, reduction in launch cost does not necessarily equate to reduction in launch price. And even if there is a reduction in launch price that would need to be weighed against the cost of indefinite storage on Earth.

We might also hope that a profitable high flight rate rocket would allow ongoing refinement and might achieve improved levels of safety. However safety and risk are relative terms and compared to other forms of transport rockets are likely to remain hazardous and not the sort of vehicle to fly highly radioactive materials on in the foreseeable future.

Finally even if radioactive waste could be put into orbit it would not be remotely practical to “put it in the Sun”. Earth orbits the Sun at around 19 miles per second and most of that velocity would have to be removed to send the payload to the Sun. Either by exorbitant use of rocket propellant or some exotic interplanetary sling shot arrangement perhaps with large solar sails.

Space is not a good place to dispose of radioactive waste.

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  • $\begingroup$ What would happen if spacecraft with containers of burned nuclear fuel in Earth orbit collide with other spacecraft, for example comsat. If it orbit is high enough radioactive debris should never reach the Earth, but can collision of for example 15t to 100t spacecraft full of burned nuclear fuel significantly increase radiation levels in high Earth orbits. Overall launching of all burned nuclear fuel into high Earth orbits shouldn't increase too much chance of creating new space debris compare to launching of multiple planned satellite constellations to LEO. $\endgroup$
    – David Cage
    Oct 13 at 16:57
  • $\begingroup$ I imagine radioactive debris would slowly be spread out around whatever orbit was selected and over time a range of adjacent orbits. This might make any access and repair difficult. But ultimately the danger of raining many tens of tonnes of highly radioactive waste down onto some random part of the Earth is the killer problem to the whole project. $\endgroup$
    – Slarty
    Oct 13 at 20:34
  • $\begingroup$ Keep in mind that the Outer Space Treaty and the Liability Convention provide for "strict liability" (that's a legal term of art) for damage caused on the ground by space operations. This liability flows directly to the launching state, even if it wasn't their fault or a government mission. Strict liability means you have to pay for damages even if you weren't negligent or did anything "wrong." $\endgroup$ Oct 15 at 15:57

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