Al Fin notes that we have 40 million years’ worth of uranium, at 10 times our current use — and we have three times as much thorium as uranium in Earth’s crust:
According to Brian Wang, there is an estimated 40 trillion tons of Uranium in Earth’s crust, and over 120 trillion tons of Thorium. Only 67,000 tons of Uranium are “consumed” yearly. If rational fuel enrichment and re-cycling is incorporated into the fission cycle, Earth would never run out of fissionable uranium.The Thorium cycle is safer and less prone to weapons proliferation. Fortunately, we have over 100 million years worth of Thorium.