And if something goes wrong and nuclear waste is scattered through the atmosphere? I think we'll get to a point where we can do it safely, but there's always a chance. Maybe if costs are low, generating energy in space and shipping it back (either as batteries or a literal wire) would be better.
It’s not a good idea, but it could be done very safely. Personally, I think nuclear power is simply to expensive to be particularly useful going forward, but IMO waste is a smaller issue than generally perceived.
Sure, you would encase them in something that could survive reentry or detonation of the rocket. Choosing a launch location and trajectory for easy recovery is also possible.
However, paying 1,000+$/lb to get rid of Nuclear waste is extremely expensive. Simply storing it in a pond for ~120 years and the stuff gets vastly less radioactive as short half-life material decays. Strontium-90 and cesium-137 have half-lives of about 30 years so you get 6% as much of them and essentially everything with a shorter half life is gone. Plutonium-238 has a longer half life of 87 years, but you also get rid of ~2/3 of that.
You still have almost off the Plutonium-239 with a half-life of 24,000 years, but that stuff is not nearly as nasty and can be reprocessed for fuel. Further, reprocessing becomes cheaper after waiting for it to cool down.
