I think it's fair to say our expertise in Uranium cycle fuel came out of the fact it generates substantially more plutonium for nuclear weapons. This was a huge reason it was selected over Thorium initially. Now, it may just be momentum. I argue it's because back in the day, it didn't product Pu.
Also keep in mind that the Uranium cycle is SIGNIFICANTLY easier. I'd argue that that played a major role. But I'm also not denying that weapons didn't play a role.
