The commercial versions of these are bigger than that. Economies of scale are still very much at play in nuclear due to the unique regulatory and supply chain i

The commercial versions of these are bigger than that. Economies of scale are still very much at play in nuclear due to the unique regulatory and supply chain issues, as well as how much not-highly-enriched fuel you need to go critical. But some folks working on nuclear farms (fields of small nukes with one security force) are dreaming of interesting new options. Regarding economics, there are lots of reactors in the USA that have their capital cost completely paid off but they're still expensive because of high Operation and Maintenance costs. A lot of this is expensive retrofits and added security costs post 9/11. More of it is that cheap natural gas in deregulated markets has brought electricity prices way down and therefore electricity sales revenue way down. This is why some nuclear plants in the US are shutting down early before their lifetime is up. It's a great tragedy because these plants are massive carbon-free baseload electricity sources. Nukes in the US make 60%+ of the carbon-free energy of the country.