Be a long time before we could repopulate the earth after some Nuke drops. With the tech you you talked about and in a more advanced futer, sounds like a viable plan lol. Hell, on a simulation of even 40 nukes dropped at the same time there is enough dust put into the upper atmosphere to blot out the sun for 10 years and cause many other substatial problems with the ecosystem. Imagine a war that used most of our nuclear arsenal, we would most likely obliterate the earth. I read somewere that the world has enough warhead stockpile to kill the human race over 10 times. Thats pretty bad.