Reply #22: The energy reserves available in Uranium (and Thorium) depend on how [View All]

[NNadir]

they are used. If we simply use Uranium in the once through cycle (as is policy in the United States) using enrichment technologies, the world reserves are about 60 years. If we use the (much wiser) technology of Uranium recycling, plutonium burning/denaturation, Thorium based fuel cycles, and we develop safe fast spectrum reactors, the world reserves of fissionable would be about 2,000 to 3,000 years. This assumes a base load consumption stabilized at the expected 2050 consumption level of 1000 exajoules, all of which is supplied by nuclear energy.

These calculations are mine, and are based on known reserves of Uranium and Thorium, chiefly available as land based ores. My figures are close to other estimates I've seen, although some people come up with much higher estimates, though I think these are dubious or assume the use of nuclear power only for electrical generation, and not for the manufacture of motor fuels and industrial heat, applications that are certainly available.

There are additionally three billion tons of Uranium in seawater, and this material would be commercially available right now if the price of Uranium were to rise to about $200-300/kg. (It is between $15-20/kg right now.) Thorium is often discarded today, as a side product from the mining of rare-earth metals with which it is often geologically associated. It has a minor use in refractory materials and gas lantern mantles.

I am a strong advocate of nuclear energy, but I believe that we should use the minimal amount of nuclear resources that we can get away with, in order to extend these resources to as many generations as is possible. In the strictest sense, nuclear resources are not renewable, but are in fact exhaustible. Although nuclear energy is the safest and cleanest option available now (except for wind power) I believe that each generation has some responsibility to accept the additional risks posed by the use of solar energy and biomass. In this way we might make nuclear energy available for tens of thousands of years, rather than thousands of years.

For the long term, we need to (ethically) reduce our population, which has already far exceeded the carrying capacity of the earth in my view.