As with pretty much any energy source, (including wind, solar, gas..) nuclear tends to get cheaper the more you build. You can look up FOAK vs NOAK and note the curves. Not sure what you're referring to re difficulty of increasing %share?
How are you measuring "fuel rod lifecycle"? And how does that possibly comparable to "$/kWh solar"?
Here's [0] a good source for some facts. You should note that accounting for the whole lifecycle of mining/processing/operating/defueling/decommissioning, nuclear is ~1/4 of the emissions of solar. And this is only considering electricity; we still have 2-3x the kwh to source for our heating requirements. You're suggesting we get that all sorted with solar & wind too?
0 - https://world-nuclear.org/information-library/energy-and-the...