They were used and the design was modified into small portable nuclear reactor, the SVBR-100, a 100MW(e) reactor that can be sold containerised and delivered on a rail flatcar.

The problem is that a) the project owners have issues getting money to finish certification b) we don't mine enough bismuth.

The second problem is pretty major issue, because as far as I know, we don't actually mine bismuth - all the bismuth available worldwide is from processing of tailings in other mines, and isn't under any kind of high production rate.

Making just a dozen or so reactors for submarines was easy. Making mass-production line would actually mean a noticeable drain on world-wide supply of bismuth!

Then there are political problems involving buying russian tech.. :(

They are, but this is because the Soviet designers thought that the improvement in power density were worth the serious disadvantage of having coolant that freezes well above room temperature.