I don't need to 'make a cogent counter argument', although I have. While your faith that government can move mountains is touching, your pie in the sky ideas don't really merit one.
We've now moved on to having whole spare power plants instead of just cores for refueling available, with no basis beyond "certainly there is ample fuel". Before you present such a thing as a baseline assumption you might at least look into the situation...or listen to someone who has been a lot closer to it.
Naval propulsion reactors run on enriched fuel. That's
how they are so small. But to make that small reactor requires about the same amount of raw Uranium ore as a gigantic civilian plant does, because the 'enrichment' process is actually just a process of discarding 99.7 percent of the Uranium you start with. So no, even 'by now' there aren't just mountains of fuel sitting around.
Second point where you are way off track, power production. While a naval propulsion plant is hell on wheels for shoving a submarine around, you are not doing the math when you put it in this hole in the ground if you are thinking it can power a 'shelter of huge proportions'. A normal small town, which uses
sunlight rather than powering LEDs to grow food, and having only a moderate amount of heavy industry, will consume about 10kW per home. So 2000 homes,
without even considering the LED food business or the fact that just maintaining the reactor will require more than a normal amount of heavy industry, will need a 20 MW power supply...and that's the electrical output capacity of a standard 100 MW submarine reactor. Now, I freely admit that I have no clue how much power would be required to grow this food, but I'm willing to assume that it cuts down the 2000 homes by at least half. So your 'massive' shelter is down to a thousand homes.