My comment was really about uranium 233, which is very hard to work with because it emits a ton of gamma rays, which means you need great care in handling it as

My comment was really about uranium 233, which is very hard to work with because it emits a ton of gamma rays, which means you need great care in handling it as you purify it from thorium waste. Yes, if you got a hold of a ton of depleted uranium and had a ton of money to burn and somehow hide what you were doing, you could breed it. I suspect you could use a neutron generator to do it at a staggering cost in electricity (at least until you bred enough fissile material that you could then sustain the rest of the breeding). But these things are not remotely trivial, and they're definitely not cheap. They're within reach of large corporations, but not small ones or individuals.