Anyone who has, and can run, a fusion reactor (Or some super-powerful laser array) is more than capable of making their own nuclear bombs more easily by another method.

>I'm going to have some very angry-looking men carrying automatic weapons showing up at my front door very quickly.

You can buy it online in the US, though not in particularly large amounts. Buy a company with a legitimate use for it, order it in bulk and voila, you have Uranium 238.