I STM reading (via HN!) that submarine nuke plants are designed not to require (or even have the affordances for) significant maintenance — that when they are “done” (fuel spent?) the power plant is discarded. If this is in fact the case I can imagine it would make for a more reliable and less expensive device.

The economics of nuclear powered subs is quite different from a commercial product. But it’s interesting to consider.

(And just for fun: imagine what effect a “right to repair” law would have…)

Good points.

In addition, military spend capabilities will more readily compensate for the other two sides of the project management triangle. And AIUI a lot of those systems, once initial development occurred, were cookie-cutter / evolutionary designs.

I also understand the mini-reactors for seafaring vessels are much less efficient - but they don't need to be hugely efficient, primarily for the reason you mention.

In any case, I expect the regulatory-driven quality of those devices is ridiculously high. Well the USA systems at least -- obviously Russia had a much less pleasant experience with small reactors on submarines.

Yes, the cost per MWh must be insane. Any nation building nuclear-powered subs and carriers have essentially unlimited R&D and construction budgets.

that only further proves the point, those cases may have more lax safety thresholds but they still wind up wildly over budget all the time.