Peak uranium? I've known (and probably you as well) about this for a while, but here is a decent article about it. I love that they broach the "zombie" issue, LOL.
"Uranium mines provide us with 40,000 tons of uranium each year. Sounds like that ought to be enough for anyone, but it comes up about 25,000 tons short of what we consume yearly in our nuclear power plants. The difference is made up by stockpiles, reprocessed fuel and re-enriched uranium — which should be completely used up by 2013. And the problem with just opening more uranium mines is that nobody really knows where to go for the next big uranium lode. Dr. Michael Dittmar has been warning us for some time about the coming shortage (PDF) and has recently uploaded a four-part comprehensive report on the future of nuclear energy and how socioeconomic change is exacerbating the effect this coming shortage will have on our power consumption. Although not quite on par with zombie apocalypse, Dr. Dittmar's final conclusions paint a dire picture, stating that options like large-scale commercial fission breeder reactors are not an option by 2013 and 'no matter how far into the future we may look, nuclear fusion as an energy source is even less probable than large-scale breeder reactors, for the accumulated knowledge on this subject is already sufficient to say that commercial fusion power will never become a reality.'"