The main challenge is peak uranium, as "The amount of uranium present in all currently known conventional reserves alone ((...)) is enough to last over 200 years at current consumption rates." https://en.wikipedia.org/wiki/Economics_of_nuclear_power_pla... therefore a real nuclear 'renaissance' implies a dangerous bet (on new uranium reserves, industrializing breeder reactors, or GenIV...)

Nuclear power: about 10% of global electricity generation ( https://en.wikipedia.org/wiki/Nuclear_power#Production ) which is about 22% of final energy ( https://en.wikipedia.org/wiki/World_energy_supply_and_consum... ). Therefore the nuclear fleet (~440 reactors) now provides a meek ~2.2 of final energy. To reach about 11% implies building 2200 reactors (good luck with this), and would only let known uranium reserves provide each reactor for ~40 years, with few hopes towards the discovery of new reserves ( https://news.ycombinator.com/item?id=38288706 ).

In such a context uranium will become more and more rare, and therefore more and more expensive... and strategic (keyword: 'embargo').