Uranium is extremely rare. Thorium is everywhere. Uranium uses just 1% of its potential energy. Thorium is 200 times more efficient. China has decided to convert its economy to a Thorium economy. Thorium has 1 million times the energy of a carbon/oxygen bond. Its energy can never run out.
The US Thorium energy programme was cancelled in 1971, for political reasons – lobbyists for conventional nuclear won the day.