Quantity. One of the big issues with nuclear power is that we aren’t building frequently enough, and therefore lose expertise and capability, which drives up costs, both from screw-ups and from not being able to amortize over a large production run. To give an analogy, imagine if Boeing only made one 737 every five years. That aircraft would be insanely expensive.
Personally, I’m bullish on the companies in the micro reactor space that have minimal site construction. I’m less bullish on Oklo, given that their application had some glaring omissions and got denied an NRC license.
The question is “What are the numbers?”
Clearly the navy uses nukes due to advantageous performance characteristics. What are the numbers that a civilian small nuke must make to be viable?