I have a lot of sympathy for what you're saying. The electrical grid badly needs to be made robust to EMP/solar flares, because even if no one detonates a nuke in orbit, eventually there will be a solar flare that will be powerful enough to have the same effect. Or some sort of cascading failure. Smaller modular grids are inherently more robust, on that you cannot be disputed.
You are also right that nuclear has much less of a carbon footprint than burning coal or any other fossil fuel. What I'm not confident of is that nuclear power of any sort can be competitive, economically, with alternatives.
Don't get me wrong, I like nuclear power in principle, but when it comes down to money, people have argued, pretty convincingly, that the fact that you have to generate heat and then convert it to power incurs so much capital expense that direct electrical generation will always be cheaper.
Direct electrical generation means that the fuel directly spins a turbine or generates electricity, examples of direct conversion:
natural gas fired turbines (the burning gas turns the turbine directly)
All flavors of nuclear power (except possibly aneutronic fusion) heat water which is converted to steam which turns turbines which generates electricity.
Here's the link that goes into the argument more thoroughly: