> 200 years / 5 gives about 40 years useful life.
Well, no, it's not that simple. Some advances would require new reactors, such as breeders, but even in a closed system with breeders there would be maybe a 2:1 ratio of traditional burner reactors to breeders (producing fuel for the burners). So even in such a scenario existing LWR's wouldn't be a stranded investment.
But even if we forget breeding for a moment, an increase in usage of uranium would make it economical to exploit poorer deposits (that 200 year figure is at current prices and with current extraction technology), increasing the total economically recoverable deposits (this is similar to practically all other mining, as technology progresses and price increases the economically recoverable deposits also increase). And at some point we will hit the crossover point where, like in the SA article you linked to earlier, extraction from seawater becomes economic. Giving an additional 60000 years of deposits with current usage.
So between breeding (about a factor of 200 improvement in resource utilization) and seawater extraction, we have enough uranium for at least 60000*200 = 12 million years with current usage. Even if we increase usage by a factor of 100 (say, getting rid of fossil fuels thus increasing electricity usage by about ~3x, and increasing the share of nuclear to, say, 50% of the total electricity usage, and still have quite some room for increasing consumption), we still have fuel for 120000 years. Probably more than enough time to get fusion working, or if not, we're hosed anyway in the long run.
> we're going to go into this with the designs we have now.
I agree with that. While there's exiting things on the horizon, it makes sense to start with what's available and mature now.
That, however, doesn't mean we're locked into that forever and ever. We can start deploying traditional LWR designs today, while at the same time commercializing breeders, seawater extraction of U, Th, and whatnot.
None of this means that a "nuclear future" will be inevitable, certainly. I just don't think that the availability of fuel is the limiting factor. AFAICS, the biggest threats to nuclear energy is an inability to deliver on time and on budget combined with political opposition killing the industry.
If wind, solar, geothermal, storage, smart grids etc. manage to kill of the fossil industry without the help of nuclear, hey, I'm ecstatic. I just think having the nuclear option on the table makes success more likely.
