Well, the fuel is only like 20% of the cost of nuclear power, with the majority being capex, so there’s really little reason to build even more expensive reactors with more regulatory issues to save on opex which isn’t even significant.
Opex "isn't significant" only in comparison to capex for nukes. Nukes' opex is, like capex, outrageously huge compared to both for renewables. Every penny spent on building nukes instead of building out renewables/storage adds to global climate disruption.