Depends on the fuel used and cooling techniques. Looking at the predominant fuel mix currently used internationally, there is only 80-90 years of nuclear material left - perhaps worse than peak oil. That's why the new emphasis by the Chinese and a few other governments on Thorium Energy & Molen-Salt Technology Inc (iThEMS) is really, really interesting. The US should begin to invest in this technology too- we invented the concept in teh 1950s and 60s, but dropped Thorium because it didn't produce any useful Plutonium byproducts needed for Nuclear Bombs. Here's a good article about the Chinese use of this: http://www.theregister.co.uk/2011/02/01/china_thorium_bet/
What I dont understand is the way we build nuclear plants - why are they not built in very large pits, with huge silos that hold a concrete slurry mix that can be realeased to flood the pit and encase the whole thing in concrete should the need arise.
