You can make nukes with material (U-233) bred in the thorium fuelcycle.
https://en.wikipedia.org/wiki/Uranium-233
There are serious diverse problems with the thorium fuelcycle, including MSR. This is the reason it is not being developed vigorously. But China and India particularly are looking into it.
Thanks. From the details I can't tell whether this https://www.nature.com/articles/s41586-022-05108-y is the process used or something else.
It could be a variation on https://pubs.rsc.org/en/content/articlehtml/2022/cc/d2cc01345b but not enough details provided, so I'll stop guessing.