chaniarts wrote:
....

subs don't have 'large' plants because they skip a lot of the safety and
containment bits. if they get a meltdown, it just goes out the bottom of the
hull.

Not really. The prime reason is they're highly enriched, much higher
power density (and much smaller total power output/reactor) than
commercial power reactors.

They have design bases that are much more stringent in terms of load
swing, maneuvering rates, ability to restart immediately after shutdown,
etc., owing to the demands placed upon them by combat readiness. Hence,
they're much more expensive per MW also.

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