Reserves for a thousand years? Is that U-235, or is that what could potentially be achieved with breeder reactors? One of the other downsides to the fast-breeder reactor is the need for a core of weapons-grade uranium to actually initiate the process. So that means having to enrich enough U-235 to start the cycle, which could get difficult as supplies of the rare isotope become depleted. Thorium does look more promising, although we should try to invest in a variety of sources. The only thing which is for sure is that conventional LWR will quickly kill nuclear power unless a more sustainable source of fuel can be procured. Until that happens, I reluctantly have to side with economics over environmental concerns. LWR actually produce very little waste in the grand scheme of things. The annual byproducts from a single 1 GW coal plant represents more than 60 years' worth of spent fuel rods from a hundred reactors. In other words, 59,000 tons of spent fuel rods actually is quite small for the electricity they generated. And although we really should secure them in repository facilities like Yucca Mountain(assuming it'll ever be completed), they'll just be kept on the back burner for the foreseeable future.