There have been hundreds of billions to trillions of dollars spent on various efforts at breeder reactors over the years. Most of them catch fire every month o

There have been hundreds of billions to trillions of dollars spent on various efforts at breeder reactors over the years. Most of them catch fire every month or dissolve themselves from the inside after a year. Turns out the idea probably needs materials that don't exist yet (but might soon?). The Russian BN 800 is the closest if you believe their government, and the chinese LFTR project has some promise. Even with the basic possibility issues solved there are a bunch of economic, resource and political issues to work through after that.