Westinghouse has made nuclear submarine reactors. The UK small modular reactor project is being run by Rolls-Royce who make the equivalent submarine reactors.

Westinghouse has made nuclear submarine reactors. The UK small modular reactor project is being run by Rolls-Royce who make the equivalent submarine reactors. Both SMR projects seem to be about 10x the power output of a submarine reactor. I'm guessing they have to use a very different level of fuel enrichment than is in subs.