Nuclear Power Forever

Bernard Cohen studied the renewability of uranium for breeder fast-reactors back in 1983…

Breeder Reactors: A renewable energy source

…concluding that uranium pulled from seawater at 6,500 tons per year was sustainable for 5 billion years. That’s 18.5 TW.yr of raw energy since uranium in a breeder can have virtually 100% of its energy potential liberated. As we humans use about 15 TW.yr from all sources annually that’s pretty good news. He argues that as crustal matter is continually dissolved and carried into the sea the total level in the ocean (over 4 billion tons) will remain much the same for aeons.

Deuterium – a fusion fuel – is available too. Some 44 trillion tons in the ocean. It produces about 300 TJ/kg energy, thus it too could last for aeons at modest power usage levels. Thorium is more plentiful than uranium in the crust, but its solubility is much lower, thus it has to be mined. In the long term, so the crust isn’t overturned for mining, uranium is the fission fuel of choice.