> wouldn't consider what the US navy does scifi.

Military small reactor designs use fuel enriched to levels higher than what we want to be standard in civillian reactors. Second, military nuclear reactors are expensive as hell, and we wouldn't want to power our society with them.

We build nuclear submarines because operationally they are unsurpassed, there's no alternative, and the operational benefits are worth sky-high costs. When it comes to the grid, we have cheaper, more flexible, and faster to deploy options.