You don't have to use the ultracentrifuge, though I don't suppose the power plant you would need for a diffusion plant would be much more attainable.
In theory, there's also direct laser-based isotope separation. It's a technology that is being actively suppressed, and that's one case where I very much in favor of that.
In theory, there's also direct laser-based isotope separation. It's a technology that is being actively suppressed, and that's one case where I very much in favor of that.