I wouldn't hold your breath but even if you don't, you will never see it.
Admittedly, all the reactors I ever worked on were large for ship propulsion
, but in addition to being, large they were heavy, complex, contaminating, expensive and dangerous for the neophyte. Everyone who worked on, or around them, had to be schooled, qualified, tested, and experienced. All directions for use and operation had to be in writing and complied with to the letter or the job stopped and the paper had to be changed. Then when the paper was changed the change had to be approved by just about the whole world.
I wouldn't want one if I ever thought they would work in a boat.