alt Hacker NewsThose reactors were also very expensive, though, weren't they? I've heard lots of people look to them as a reason that SMRs might work, but not because the naval reactors were cheap. Plus they use uranium enriched to levels that we typically don't allow in civilian reactors...
Even at military contracting prices, estimates put them at $100-200M each IIRC. That's not terrible.
The highly enriched fuel is used because it simplifies the design and maintenance. It eliminates all the machinery you'd need to support things like operational refueling of the reactor. Old designs still needed to be rebuilt every 25 years but the new ones are sealed systems that are never supposed to be cracked open over their design life.
I think the main reason we don't use HEU in civilian reactors is non-proliferation concerns, valid or not. Ideally you'd want maximally simple, sealed reactors for the same reason the US Navy does.