We aren't even responsible enough with the nuclear assets and waste we already have, and we're going to have to actively look after that lot for millennia to come. You can't just walk away from a spent fuel waste facility - you have to run it, or it will eventually leak radioactive isotopes into the environment. We aren't even doing that right now, so how do we expect our decendents to have the will and knowledge to do that in 2200? If we're still around at all.