So why aren't we using Thorium reactors?

Government of Norway and Westinghouse (USA and Japan) are developing a Thorium reactor program in Norway.

The place where thorium is proven either way could be China. The country is serious about weaning itself off of fossil fuels and making nuclear power their primary energy source. Fourteen nuclear power reactors are in operation in China today, another 25 under construction, and there are plans to build more. And in 2011 they announced plans to build a thorium, molten salt reactor. So whether it be Norway, the UK, China, or some other forward-thinking countries, we’ll soon find out if thorium reactors are better than uranium ones, at which point more countries may want to join the thorium chain reaction.